Camptothecin compound and conjugate containing same and use thereof

Abstract

The present invention provides a novel camptothecin compound and a conjugate containing same. The present invention also provides a use of the camptothecin compound and the conjugate in the treatment or prevention of diseases.

Description

Camptothecin compounds, conjugates thereof and uses thereof

[0001] This international patent application claims priority to Chinese patent application No. 202410635906.4, filed on May 21, 2024, the entire contents of which are incorporated herein by reference for all purposes. TECHNICAL FIELD

[0002] The present application belongs to the field of medicine, and specifically relates to camptothecin compounds, conjugates thereof and uses thereof. BACKGROUND

[0003] The concept of antibody-drug conjugate (ADC) or ADC drug has a long history. As early as 1913, Professor Paul Ehrlich, a Nobel Prize winner, first proposed the concept of "magic bullet", that is, installing cytotoxic drugs on specific monoclonal antibodies to achieve targeted killing of tumor cells. The currently marketed ADC drug is based on this theory, which connects cytotoxic drugs to monoclonal antibodies, so that monoclonal antibodies act as carriers to transport small molecule cytotoxic drugs to target tumor cells in a targeted manner.

[0004] The first generation of ADC drugs was an attempt to use anti-mouse white blood cell immunoglobulin and methotrexate conjugation for the treatment of leukemia in 1958. Mylotarg was the first ADC drug to be marketed, approved by FDA in 2000 for the treatment of acute myeloid leukemia, but it was withdrawn from the market due to serious fatal liver damage and no obvious survival benefit. The shortcomings of the first generation of ADC drugs are: the antibody is a mouse antibody, the cytotoxin is insufficient and the site is low expression.

[0005] The second generation of ADC drugs started with trastuzumab emtansine, which was the first ADC drug targeting breast cancer to be approved. The most successful ADC drug in the field of hematological tumors is brentuximab vedotin, which mainly targets classical Hodgkin's lymphoma and anaplastic large cell lymphoma. The advantages of the second generation of ADC drugs are: diversified target antigen development, humanized antibodies, and the disadvantages are: too low or too high drug loading rate, narrow therapeutic window and low effectiveness.

[0006] The third generation of ADC drugs is represented by enfortumab, which is the second ADC drug targeting solid tumors, suitable for patients who do not respond to PD-1 / PD-L1 antibody therapy, but it is not sensitive to microtubule inhibitors.

[0007] The drug conjugate compound that targets the biologically active molecule for transport into a target cell can also be a ligand-drug conjugate (LDC), in which the ligand can be a peptide or a small molecule. In comparison with the antibody-drug conjugate in which the antibody is used for targeted localization, the ligand-drug conjugate can adopt the peptide or small molecule orientation, and the ligand and drug with targeting effect in the ligand-drug conjugate usually have accurate values. However, the application of LDC also faces many challenges in terms of bioavailability, stability, efficacy, toxicity and the like.

[0008] At present, there is still a need to develop drug molecules and conjugates thereof with reasonable molecular structure design and improved pharmacological activity. SUMMARY

[0009] In one aspect, the present application provides a compound of formula (D), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof:

[0010] wherein,

[0011] * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0012] A1is selected from -C 0-6 alkylene-OH, -C 0-6 alkylene-NH2or -C 0-6 alkylene-SH;

[0013] A2is selected from -(CR a R b ) k - or -(CR a R b ) k -O-(CR a R b ) k -;

[0014] R a and R b are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0015] Alternatively, two R a on two different carbon atoms are connected together with the carbon atoms to which they are attached to form a C 3-10 cycloalkylene, 3-10 membered heterocyclylene, C 6-10 arylene or 5-10 membered heteroarylene;

[0016] k is 2, 3, 4, 5, or 6;

[0017] A3is selected from -C 0-6 alkylene-NH-C 0-6 alkylene-, -C 0-6 alkylene-C(O)-C 0-6 alkylene-, -C 0-6 alkylene-NHC(O)-C 0-6 alkylene-, -C 0-6 alkylene-C(O)NH-C 0-6 alkylene-, -C 0-6 alkylene-NHC(O)O-C 0-6 alkylene- or -C 0-6 alkylene-NHC(O)NH-C 0-6 alkylene-;

[0018] A1, A2, and A3are optionally substituted with 1, 2, 3, 4, or 5 R A groups, as chemically allowed;

[0019] R1and R2are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or C 1-6 haloalkoxy;

[0020] Alternatively, R1and R2, or R2and the carbon atom to which R2is attached, are connected to form a C 5-10 cycloalkyl, 5-10 membered heterocyclyl, C 6-10 aryl, or 5-10 membered heteroaryl;

[0021] R1, R2, and the ring formed by R1and R2are optionally substituted with 1, 2, 3, 4, or 5 R B groups;

[0022] R3and R4are independently selected from halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or C 1-6 haloalkoxy;

[0023] Alternatively, R3and R4are connected, together with the carbon atom to which both are attached, to form a C 4-10 cycloalkyl, 4-10 membered heterocyclyl, C 6-10 aryl, or 5-10 membered heteroaryl;

[0024] R3, R4, and the ring formed by R3and R4are optionally substituted with 1, 2, 3, 4, or 5 R Csubstituted;

[0025] R5is selected from -NH2or -OH, preferably OH;

[0026] R6is selected from C 3-10 cycloalkyl, 3-10 membered heterocyclyl, C 6-10 aryl, 5-10 membered heteroaryl, -C 1-6 alkylene-C 3-10 cycloalkyl, -C 1-6 alkylene-3-10 membered heterocyclyl, -C 1-6 alkylene-C 6-10 aryl or -C 1-6 alkylene-5-10 membered heteroaryl, preferably -C 1-6 alkylene-C 3-10 cycloalkyl;

[0027] R6is optionally substituted with 1, 2, 3, 4, or 5 R D substituted;

[0028] each R A , R B , R C , and R D is independently selected from deuterium, halogen, -C 0-6 alkylene-OH, -C 0-6 alkylene-CN, -C 0-6 alkylene-NH2, C 1-6 alkyl, -C 0-6 alkylene-C 1-6 alkoxy, -C 0-6 alkylene-C 1-6 haloalkyl, -C 0-6 alkylene-C 1-6 haloalkoxy, -C 0-6 alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10 membered heterocyclyl, -C 0-6 alkylene-C 6-10 aryl or -C 0-6 alkylene-5-10 membered heteroaryl.

[0029] In another aspect, the present application relates to a linker-drug conjugate selected from a compound of Formula (LD), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof:

[0030] L1— L2— L3— D (LD)

[0031] wherein,

[0032] D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity;

[0033] L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0034] L 1a is a thiol reactive group, for example

[0035] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; optionally 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced with a heteroatom of O, S, N, while each -CH2- in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1a ;

[0036] each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can join to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0037] L 1b is optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0038] L 1c is selected from a chemical bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0039] L 1d is selected from a chemical bond, C 1-10 alkylene, C 2-10 alkenylene or C2-10 Imyynyl group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2- 10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1c replace;

[0040] Each R 1c Independently selected from H, halogen, C 1-6 Alkyl, C 1-6 Haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -NHC(O)-(OC) 1- 4-alkylene) n -C 1-4 Alkyl, -C(O)-(OC) 1-4 Alkylene) n -C 1-4 Alkyl group; or, any two R atoms on the same or different carbon atoms. 1c Can be connected to form C 3-10 Cycloalkylene or 3-10 membered heterocyclic cycloalkylene groups;

[0041] n is selected from 1, 2, 3, 4, 5, or 6;

[0042] L 1c and L 1d It can be a chemical bond at the same time;

[0043] L 1e Selected from -C(O)-, -NHC(O)-, or -C(O)-NHC(O)-;

[0044] L2 is selected from a divalent peptidic group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0045] L3 is an optionally substituted or unsubstituted spacer.

[0046] In another aspect, the present application relates to a Ligand Drug Conjugate of formula (X), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0047] T— [L1’— L2— L3— D] y (X)

[0048] wherein,

[0049] T is a targeting moiety;

[0050] D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity;

[0051] y is selected from 1 to 20;

[0052] L1’ is -L 1a ’-L 1b -L 1c -L 1d -L 1e -;

[0053] L 1a ’ is formed by reaction of a thiol reactive group L 1a with the targeting moiety T, for example L 1a ’ is attached to T through the # end;

[0054] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10Isomerynethiol; the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2-10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1a replace;

[0055] Each R 1a Independently selected from H, halogen, C 1-6 Alkyl or C 1-6 Haloalkyl; or, two R atoms on any same or different carbon atoms. 1a Can be connected to form C 3-10 Cycloalkylene or 3-10 membered heterocyclic cycloalkylene groups;

[0056] L 1b Optionally replaced by a hydrophilic group, said hydrophilic group being selected from: R 1b and R 1b’ Independently selected from H and C 1-6 Alkyl or C 1- 6-Hydroalkyl; or, R 1b R 1b’ Together with the carbon atoms they are attached to, they form C 3-7 Cycloalkylene or 3-7 membered heterocyclic alkylene;

[0057] L 1c Selected from chemical bonds, -C(O)-, -C(O)NH-, or -NHC(O)-;

[0058] L 1d Selected from chemical bonds, C 1-10 Alkylene, C 2-10 imide or C 2-10 Imyynyl group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2- 10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1c replace;

[0059] Each R 1c Independently selected from H, halogen, C 1-6 Alkyl, C1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0060] n is selected from 1, 2, 3, 4, 5 or 6;

[0061] L 1c and L 1d may simultaneously be a chemical bond;

[0062] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0063] L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0064] L3 is an optionally substituted or unsubstituted spacer.

[0065] In another aspect, the present application relates to a pharmaceutical composition comprising at least one compound selected from the group consisting of:

[0066] a compound of Formula (D) as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof; and / or

[0067] a Ligand Drug Conjugate of Formula (X) as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof.

[0068] In another aspect, the present application relates to a method for preventing and / or treating a disease in a subject in need thereof, comprising administering to the subject: a compound of Formula (D) as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof; or

[0069] a Ligand Drug Conjugate of Formula (X) as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof.

[0070] In another aspect, the present application relates to a compound of Formula (D) as described herein, a compound of Formula (LD) as described herein, or a Ligand Drug Conjugate as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof, for use in the prevention and / or treatment of a disease.

[0071] In another aspect, the present application relates to the use of a compound of Formula (D) as described herein, a compound of Formula (LD) as described herein, or a Ligand Drug Conjugate as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof, for the manufacture of a medicament for the prevention and / or treatment of a disease.

[0072] In a more particular aspect, the disease is selected from a tumor, such as a sarcoma or a carcinoma;

[0073] Preferably, the disease is selected from the group consisting of leukemia, fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma, lymphoma, lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, gastric cancer, colon cancer, rectal cancer, small intestine cancer, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinoma, cystadenocarcinoma, medullary carcinoma, bronchogenic carcinoma, esophageal carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilms' tumor, cervical cancer, uterine cancer, testicular cancer, lung cancer, small cell lung carcinoma, non-small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, schwannoma, meningioma, melanoma, neuroblastoma, and retinoblastoma.

[0074] More preferably, the disease is cancer selected from the group consisting of breast cancer and gastric cancer.

[0075] DETAILED DESCRIPTION

[0076] DEFINITIONS

[0077] CHEMICAL DEFINITIONS

[0078] The definitions of specific functional groups and chemical terms are more fully described below.

[0079] When a range of values is listed, it is intended to include each value and sub-range within the range. For example, "C 1-6 "alkyl" includes C1, C2, C3, C4, C5, C6, C 1-6 , C 1-5 , C 1-4 , C 1-3 , C 1-2 , C 2-6 , C 2-5 , C 2-4 , C 2-3 , C 3-6 , C 3-5 , C 3-4 , C 4-6 , C 4-5 and C 5-6 alkyl groups.

[0080] "C 1-10 alkyl" means a straight or branched chain saturated hydrocarbon group having from 1 to 10 carbon atoms. In some embodiments, C 1-8 alkyl, C 1-6 alkyl and C 1-4 alkyl groups are preferred. C 1-6Examples of alkyl groups include: methyl (Ci), ethyl (C2), n-propyl (C3), i-propyl (C3), n-butyl (C4), t-butyl (C4), sec-butyl (C4), i-butyl (C4), n-pentyl (C5), 3-pentyl (C5), amyl (C5), neopentyl (C5), 3-methyl-2-butyl (C5), t-amyl (C5), and n-hexyl (C6). The term "C 1-6 Alkyl also includes heteroalkyl, wherein one or more (e.g., 1, 2, 3, or 4) carbon atoms are replaced by a heteroatom (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus). Alkyl groups can be optionally substituted by one or more substituents, e.g., by 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. Conventional alkyl abbreviations include: Me (-CH3), Et (-CH2CH3), iPr (-CH(CH3)2), nPr (-CH2CH2CH3), n-Bu (-CH2CH2CH2CH3), or i-Bu (-CH2CH(CH3)2).

[0081] "C 2-10 Alkenyl refers to a straight or branched chain hydrocarbon group having from 2 to 10 carbon atoms and at least one carbon-carbon double bond. In some embodiments, C 2-6 Alkenyl is preferred. C 2-6 Examples of alkenyl groups include: ethenyl (C2), 1-propenyl (C3), 2-propenyl (C3), 1-butenyl (C4), 2-butenyl (C4), butadienyl (C4), pentenyl (C5), pentadienyl (C5), hexenyl (C6), and the like. The term "C 2-6 Alkenyl also includes heteroalkenyl, wherein one or more (e.g., 1, 2, 3, or 4) carbon atoms are replaced by a heteroatom (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus). Alkenyl groups can be optionally substituted by one or more substituents, e.g., by 1 to 5 substituents, 1 to 3 substituents, or 1 substituent.

[0082] "C 2-10 Alkynyl refers to a straight or branched chain hydrocarbon group having from 2 to 10 carbon atoms, at least one carbon-carbon triple bond, and optionally one or more carbon-carbon double bonds. In some embodiments, C 2-6 Alkynyl is preferred. C 2-6 Examples of alkynyl groups include, but are not limited to: ethynyl (C2), 1- propynyl (C3), 2-propynyl (C3), 1-butynyl (C4), 2-butynyl (C4), pentynyl (C5), hexynyl (C6), and the like. The term "C 2-6"Alkyne" also includes heteroyne, wherein one or more (e.g., 1, 2, 3 or 4) carbon atoms are replaced by heteroatoms (e.g., oxygen, sulfur, nitrogen, boron, silicon, phosphorus). The alkynyl group may be optionally substituted by one or more substituents, for example, by 1 to 5 substituents, 1 to 3 substituents or 1 substituent.

[0083] "Halogen" or "halogen" refers to fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

[0084] Therefore, "C" 1-6 "Halogenated alkyl" refers to the above "C 1-6 "alkyl" is substituted with one or more halogen groups. In some embodiments, C 1-4 Halogenated alkyl groups are particularly preferred, and C4 groups are more preferred. 1-2 Halogenated alkyl groups. Exemplary alkyl halogenated groups include, but are not limited to: -CF3, -CH2F, -CHF2, -CHFCH2F, -CH2CHF2, -CF2CF3, -CCl3, -CH2Cl, -CHCl2, 2,2,2-trifluoro-1,1-dimethyl-ethyl, etc. The alkyl halogenated group can be substituted at any available connection point, for example, 1 to 5 substituents, 1 to 3 substituents, or 1 substituent.

[0085] “C 1-6 "Alkoxy" refers to the -OR group, where R is C as defined above. 1-6 Alkyl group. C 1-4 Alkyl groups are preferred.

[0086] “C 1-10 "alkylene" refers to the alkylene group after removing C 1-10 The alkyl group is a divalent group formed by another hydrogen atom, and can be substituted or unsubstituted. In some embodiments, C 1-8 Alkylene, C 1-6 Alkylene, C 1-4 Alkylene and C 1-2 Alkylenes are preferred. Unsubstituted alkylenes include, but are not limited to: methylene (-CH2-), ethylene (-CH2CH2-), propylene (-CH2CH2CH2-), butylene (-CH2CH2CH2CH2-), pentylene (-CH2CH2CH2CH2CH2-), hexylene (-CH2CH2CH2CH2CH2CH2-), and so on. Exemplary substituted alkylenes, for example, those substituted with one or more alkyl (methyl) groups, include, but are not limited to: substituted methylene (-CH(CH3)-, -C(CH3)2-), substituted ethylene (-CH(CH3)CH2-, -CH2CH(CH3)-, -C(CH3)2CH2-, -CH2C(CH3)2- substituted propylene groups (-CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -CH2CH2CH(CH3)-, -C(CH3)2CH2CH2-, -CH2C(CH3)2CH2-, -CH2CH2C(CH3)2-), and the like.

[0087] "C 2-10 alkenylene" refers to a divalent radical formed by the removal of two hydrogens from a C 2-10 alkenyl group, and can be substituted or unsubstituted. In some embodiments, C 2-8 alkenylene, C 4-6 alkenylene, C 1-4 alkenylene, C 2-4 alkenylene is preferred.

[0088] "C 2-10 alkynylene" refers to a divalent radical formed by the removal of two hydrogens from a C 2-10 alkynyl group, and can be substituted or unsubstituted. In some embodiments, C 2-8 alkynylene, C 4-6 alkynylene, C 1-4 alkynylene, C 2-4 alkynylene is preferred.

[0089] "C 3-10 cycloalkyl" refers to a non-aromatic hydrocarbon radical of from 3 to 10 ring carbon atoms and zero heteroatoms. In some embodiments, C 5-7 cycloalkyl, C 3-7 cycloalkyl and C 3-5 cycloalkyl is particularly preferred, more preferred C 5-6 cycloalkyl. Cycloalkyl also includes ring systems in which the above cycloalkyl ring is fused with one or more aryl or heteroaryl rings, where the point of attachment is on the cycloalkyl ring, and in such cases the number of carbons represents the number of carbons in the cycloalkyl ring system. Exemplary cycloalkyl groups include, but are not limited to, cyclopropyl (C3), cyclopropenyl (C3), cyclobutyl (C4), cyclobutenyl (C4), cyclopentyl (C5), cyclopentenyl (C5), cyclohexyl (C6), cyclohexenyl (C6), cyclohexadienyl (C6), cycloheptyl (C7), cycloheptenyl (C7), cycloheptadienyl (C7), cycloheptatrienyl (C7), and the like. The cycloalkyl radical can be optionally substituted by one or more substituents, for example, by one to five substituents, one to three substituents, or one substituent.

[0090] "3-10 membered heterocyclyl" refers to a 3- to 10-membered non-aromatic ring system having ring carbon atoms and 1 to 5 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon. In heterocyclyl groups containing one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valence permits. In some embodiments, 4-9 membered heterocyclyl groups are preferred, which are 4- to 9-membered non-aromatic ring systems having ring carbon atoms and 1 to 5 ring heteroatoms; in some embodiments, 5-8 membered heterocyclyl groups are preferred, which are 5- to 8-membered non-aromatic ring systems having ring carbon atoms and 1 to 5 ring heteroatoms; in some embodiments, 3-8 membered heterocyclyl groups are preferred, which are 3- to 8-membered non-aromatic ring systems having ring carbon atoms and 1 to 4 ring heteroatoms; 3-7 membered heterocyclyl groups are preferred, which are 3- to 7-membered non-aromatic ring systems having ring carbon atoms and 1 to 3 ring heteroatoms; 3-5 membered heterocyclyl groups are preferred, which are 3- to 5-membered non-aromatic ring systems having ring carbon atoms and 1 to 2 ring heteroatoms; 4-7 membered heterocyclyl groups are preferred, which are 4- to 7-membered non-aromatic ring systems having ring carbon atoms and 1 to 3 ring heteroatoms; 4-6 membered heterocyclyl groups are preferred, which are 4- to 6-membered non-aromatic ring systems having ring carbon atoms and 1 to 3 ring heteroatoms; 3-5 membered heterocyclyl groups are preferred, which are 3- to 5-membered non-aromatic ring systems having ring carbon atoms and 1 to 3 ring heteroatoms; and 5-6 membered heterocyclyl groups are preferred, which are 5- to 6-membered non-aromatic ring systems having ring carbon atoms and 1 to 3 ring heteroatoms. Heterocyclyl also includes ring systems in which the above heterocyclyl ring is fused with one or more cycloalkyl rings, wherein the point of attachment is on the cycloalkyl ring, or with one or more aryl or heteroaryl rings, wherein the point of attachment is on the heterocyclyl ring; and in such cases the number of ring members continues to refer to the number of ring members in the heterocyclyl ring system. Exemplary 3-membered heterocyclyl groups containing one heteroatom include, but are not limited to: aziridinyl, oxiranyl, thiorenyl. Exemplary 4-membered heterocyclyl groups containing one heteroatom include, but are not limited to: azetidinyl, oxetanyl, and thietanyl. Exemplary 5-membered heterocyclyl groups containing one heteroatom include, but are not limited to: tetrahydrofuranyl, dihydrofuranyl, tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl, and pyrrolyl-2,5-dione. Exemplary 5-membered heterocyclyl groups containing two heteroatoms include, but are not limited to: dioxolanyl, oxasulfuranyl, disulfuranyl, and oxazolidin-2-one. Exemplary 5-membered heterocyclyl groups containing three heteroatoms include, but are not limited to: triazolinyl, oxadiazolinyl, and thiadiazolinyl. Exemplary 6-membered heterocyclyl groups containing one heteroatom include, but are not limited to: piperidinyl, tetrahydropyranyl, dihydropyridinyl, and thianyl. Exemplary 6-membered heterocyclyl groups containing two heteroatoms include, but are not limited to: piperazinyl, morpholinyl, dithianyl, dioxanyl.Exemplary 6-membered heterocyclyl groups containing three heteroatoms include, without limitation, hexahydrotriazinanyl. Exemplary 7-membered heterocyclyl groups containing one heteroatom include, without limitation, azepanyl, oxepanyl, and thiepanyl. Exemplary 5-membered heterocyclyl groups fused to a C6aryl ring (also referred to herein as 5,6-bicyclic heterocyclyl groups) include, without limitation, indolinyl, isoindolinyl, dihydrobenzofuranyl, dihydrobenzothienyl, benzoxazolinonyl, and the like. Exemplary 6-membered heterocyclyl groups fused to a C6aryl ring (also referred to herein as 6,6-bicyclic heterocyclyl groups) include, without limitation, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and the like. Heterocyclyl groups can be optionally substituted by one or more substituents, for example, by 1 to 5 substituents, 1 to 3 substituents, or 1 substituent.

[0091] "C 6-10 Aryl" refers to a monocyclic or polycyclic (e.g., bicyclic) 4n+2 aromatic ring system (e.g., having 6 or 10 p electrons shared in a cyclic array) having from 6-10 ring carbon atoms and zero heteroatoms. In some embodiments, the aryl group has six ring carbon atoms ("C6 aryl"; e.g., phenyl). In some embodiments, the aryl group has ten ring carbon atoms ("C10 aryl"; e.g., naphthyl, e.g., 1-naphthyl and 2-naphthyl). Aryl also includes ring systems in which the above-described aryl ring is fused to one or more cycloalkyl or heterocyclyl rings, with the point of attachment being on the aryl ring, in which case the number of carbon atoms designates the number of carbon atoms in the aryl ring system. Aryl groups can be optionally substituted by one or more substituents, for example, by 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. 10 Aryl" refers to a monocyclic or polycyclic (e.g., bicyclic) 4n+2 aromatic ring system (e.g., having 6 or 10 p electrons shared in a cyclic array) having from 6-10 ring carbon atoms and zero heteroatoms. In some embodiments, the aryl group has six ring carbon atoms ("C6 aryl"; e.g., phenyl). In some embodiments, the aryl group has ten ring carbon atoms ("C10 aryl"; e.g., naphthyl, e.g., 1-naphthyl and 2-naphthyl). Aryl also includes ring systems in which the above-described aryl ring is fused to one or more cycloalkyl or heterocyclyl rings, with the point of attachment being on the aryl ring, in which case the number of carbon atoms designates the number of carbon atoms in the aryl ring system. Aryl groups can be optionally substituted by one or more substituents, for example, by 1 to 5 substituents, 1 to 3 substituents, or 1 substituent.

[0092] "5-10 membered heteroaryl" refers to a radical of a 5-10 membered monocyclic or bicyclic 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in a cyclic array) having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur. In heteroaryl groups containing one or more nitrogen atoms, the point of attachment can be a carbon or a nitrogen atom, as valence permits. Heteroaryl bicyclic systems can include one or more heteroatoms in one or both rings. Heteroaryl also includes ring systems wherein an above-described heteroaryl ring is fused with one or more cycloalkyl or heterocyclyl rings, and the point of attachment is on the heteroaryl ring, in which case the number of carbon atoms indicates the number of carbon atoms in the heteroaryl ring system. In some embodiments, 5-9 membered heteroaryl is preferred, which is a 5-9 membered monocyclic or bicyclic 4n+2 aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms. In other embodiments, 5-6 membered heteroaryl is particularly preferred, which is a 5-6 membered monocyclic or bicyclic 4n+2 aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms. Exemplary 5-membered heteroaryl groups containing one heteroatom include, but are not limited to, pyrrolyl, furanyl, and thiophenyl. Exemplary 5-membered heteroaryl groups containing two heteroatoms include, but are not limited to, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, and isothiazolyl. Exemplary 5-membered heteroaryl groups containing three heteroatoms include, but are not limited to, triazolyl, oxadiazolyl (e.g., 1,2,4-oxadiazolyl), and thiadiazolyl. Exemplary 5-membered heteroaryl groups containing four heteroatoms include, but are not limited to, tetrazolyl. Exemplary 6-membered heteroaryl groups containing one heteroatom include, but are not limited to, pyridinyl. Exemplary 6-membered heteroaryl groups containing two heteroatoms include, but are not limited to, pyridazinyl, pyrimidinyl, and pyrazinyl. Exemplary 6-membered heteroaryl groups containing three or four heteroatoms include, but are not limited to, triazinyl and tetrazinyl, respectively. Exemplary 7-membered heteroaryl groups containing one heteroatom include, but are not limited to, azepinyl, oxepinyl, and thiepinyl. Exemplary 5,6-bicyclic heteroaryl groups include, but are not limited to, indolyl, isoindolyl, indazolyl, benzotriazolyl, benzothiophenyl, isobenzothiophenyl, benzofuranyl, benzoisofuranyl, benzoimidazolyl, benzoxazolyl, benzoisoxazolyl, benzoxadiazolyl, benzothiazolyl, benzoisothiazolyl, benzothiadiazolyl, indolizinyl, and purinyl. Exemplary 6,6-bicyclic heteroaryl groups include, but are not limited to, naphthyridinyl, pteridinyl, quinolinyl, isoquinolinyl, cinnolinyl, quinoxalinyl, phthalazinyl, and quinazolinyl. Heteroaryl groups can be optionally substituted with one or more substituents, for example, with 1 to 5 substituents, 1 to 3 substituents, or 1 substituent.

[0093] "Carbonyl," whether used alone or in combination with other terms, refers to -C(O)-.

[0094] "Oxo" refers to =O.

[0095] "thio" denotes =S.

[0096] Alkyl, alkenyl, alkynyl, alkylene, alkenylene, alkynylene, cycloalkyl, heterocyclyl, aryl, and heteroaryl groups defined herein are optionally substituted groups.

[0097] Exemplary substituents on carbon atoms include, but are not limited to: halogen, -CN, -NO2, -N3, -SO2H, -SO3H, -OH, -OR aa , -ON(R bb )2, -N(R bb )2, -N(R bb )3 + X - , -N(OR cc )R bb , -SH, -SR aa , -SSR cc , -C(=O)R aa , -CO2H, -CHO, -C(OR cc )2, -CO2R aa , -OC(=O)R aa , -OCO2R aa , -C(=O)N(R bb )2, -OC(=O)N(R bb )2, -NR bb C(=O)R aa , -NR bb CO2R aa , -NR bb C(=O)N(R bb )2, -C(=NR bb )R aa , -C(=NR bb )OR aa , -OC(=NR bb )R aa , -OC(=NR bb )OR aa , -C(=NR bb )N(R bb )2, -OC(=NR bb )N(R bb )2, -NR bb C(=NR bb )N(R bb )2, -C(=O)NR bb SO2R aa , -NR bb SO2R aa , -SO2N(Rbb )2, -SO2R aa , -SO2OR aa , -OSO2R aa , -S(=O)R aa , -OS(=O)R aa , -Si(R aa )3, -OSi(R aa )3, -C(=S)N(R bb )2, -C(=O)SR aa , -C(=S)SR aa , -SC(=S)SR aa , -SC(=O)SR aa , -OC(=O)SR aa , -SC(=O)OR aa , -SC(=O)R aa , -P(=O)2R aa , -OP(=O)2R aa , -P(=O)(R aa )2, -OP(=O)(R aa )2, -OP(=O)(OR cc )2, -P(=O)2N(R bb )2, -OP(=O)2N(R bb )2, -P(=O)(NR bb )2, -OP(=O)(NR bb )2, -NR bb P(=O)(OR cc )2, -NR bb P(=O)(NR bb )2, -P(R cc )2, -P(R cc )3, -OP(R cc )2, -OP(R cc )3, -B(R aa )2, -B(OR cc )2, -BR aa (OR cc ), alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd groups;

[0098] or two geminal hydrogens on a carbon atom are replaced with a group =O, =S, =NN(R bb )2, =NNR bb C(=O)R aa, =NNR bb C(=O)OR aa , =NNR bb S(=O)2R aa , =NR bb or =NOR cc substituted;

[0099] R aa each independently is selected from alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl, or two R aa groups are combined to form a heterocyclyl or heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd groups;

[0100] R bb each independently is selected from: hydrogen, -OH, -OR aa , -N(R cc )2, -CN, -C(=O)R aa , -C(=O)N(R cc )2, -CO2R aa , -SO2R aa , -C(=NR cc )OR aa , -C(=NR cc )N(R cc )2, -SO2N(R cc )2, -SO2R cc , -SO2OR cc , -SOR aa , -C(=S)N(R cc )2, -C(=O)SR cc , -C(=S)SR cc , -P(=O)2R aa , -P(=O)(R aa )2, -P(=O)2N(R cc )2, -P(=O)(NR cc )2, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl, or two R bb groups are combined to form a heterocyclyl or heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd groups;

[0101] R cc each independently is selected from hydrogen, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl, or two Rcc groups to form a heterocyclyl or heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd groups;

[0102] R dd is independently selected from the group consisting of: halogen, -CN, -NO2, -N3, -SO2H, -SO3H, -OH, -OR ee , -ON(R ff )2, -N(R ff )2, -N(R ff )3 + X - , -N(OR ee )R ff , -SH, -SR ee , -SSR ee , -C(=O)R ee , -CO2H, -CO2R ee , -OC(=O)R ee , -OCO2R ee , -C(=O)N(R ff )2, -OC(=O)N(R ff )2, -NR ff C(=O)R ee , -NR ff CO2R ee , -NR ff C(=O)N(R ff )2, -C(=NR ff )OR ee , -OC(=NR ff )R ee , -OC(=NR ff )OR ee , -C(=NR ff )N(R ff )2, -OC(=NR ff )N(R ff )2, -NR ff C(=NR ff )N(R ff )2, -NR ff SO2R ee , -SO2N(R ff )2, -SO2R ee , -SO2OR ee , -OSO2R ee , -S(=O)R ee , -Si(R ee)3, -OSi(R ee )3, -C(=S)N(R ff )2, -C(=O)SR ee , -C(=S)SR ee , -SC(=S)SR ee , -P(=O)2R ee , -P(=O)(R ee )2, -OP(=O)(R ee )2, -OP(=O)(OR ee )2, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R gg groups, or two geminal R dd substituents can combine to form =O or =S;

[0103] each R ee is independently selected from alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, and heteroaryl, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R gg groups;

[0104] each R ff is independently selected from hydrogen, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl, or two R ff groups combine to form a heterocyclyl or heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R gg groups;

[0105] each R gg is independently halogen, -CN, -NO2, -N3, -SO2H, -SO3H, -OH, -OC 1-6 alkyl, -ON(C 1-6 alkyl)2, -N(C 1-6 alkyl)2, -N(C 1-6 alkyl)3 + X - , -NH(C 1-6 alkyl)2 + X - , -NH2(C 1-6 alkyl) + X - , -NH3 + X - , -N(OC 1-6Alkyl)(C 1-6 Alkyl), -N(OH)(C 1-6 Alkyl groups, -NH(OH), -SH, -SC 1-6 Alkyl, -SS(C 1-6 Alkyl), -C(=O)(C 1-6 Alkyl group, -CO2H, -CO2(C 1- 6-alkyl), -OC (=O)(C 1-6 Alkyl), -OCO2(C 1-6 Alkyl groups, -C(=O)NH2, -C(=O)N(C 1-6 Alkyl)2、-OC(=O)NH(C 1-6 Alkyl), -NHC(=O)(C 1-6 alkyl), -N(C) 1-6 Alkyl)C(=O)(C 1-6 alkyl), -NHCO2(C 1-6 Alkyl), -NHC(=O)N(C 1-6 Alkyl)2、-NHC(=O)NH(C 1-6 Alkyl groups, -NHC(=O)NH2, -C(=NH)O(C 1-6 Alkyl), -OC (=NH)(C 1-6 Alkyl group), -OC (=NH)OC 1-6 Alkyl group, -C(=NH)N(C 1-6 Alkyl)2、-C(=NH)NH(C 1-6 Alkyl groups, -C(=NH)NH2, -OC(=NH)N(C 1-6 Alkyl)2、-OC(NH)NH(C 1- 6-alkyl), -OC(NH)NH2, -NHC(NH)N(C 1-6 Alkyl)2, -NHC(=NH)NH2, -NHSO2(C 1-6 Alkyl), -SO2N(C 1-6 alkyl)2、-SO2NH(C 1-6 Alkyl groups, -SO2NH2, -SO2C 1-6 Alkyl, -SO2OC 1-6 Alkyl, -OSO2C 1-6 Alkyl, -SOC 1-6 Alkyl, -Si(C) 1-6 Alkyl)3、-OSi(C 1-6 Alkyl)3, -C(=S)N(C 1-6 Alkyl)2、C(=S)NH(C 1-6 Alkyl), C(=S)NH2, -C(=O)S(C 1-6alkyl, -C(=S)SC 1- 6alkyl, -SC(=S)SC 1-6 alkyl, -P(=O)2(C 1-6 alkyl), -P(=O)(C 1-6 alkyl)2, -OP(=O)(C 1-6 alkyl)2, -OP(=O)(OC 1-6 alkyl)2, C 1-6 alkyl, C 1-6 haloalkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C7cycloalkyl, C6-C 10 aryl, C3-C7heterocyclyl, C5-C 10 heteroaryl; or two geminal R gg substituents can combine to form =O or =S; wherein X - is a counterion.

[0106] Exemplary substituents on a nitrogen atom include, but are not limited to: hydrogen, -OH, -OR aa , -N(R cc )2, -CN, -C(=O)R aa , -C(=O)N(R cc )2, -CO2R aa , -SO2R aa , -C(=NR bb )R aa , -C(=NR cc )OR aa , -C(=NR cc )N(R cc )2, -SO2N(R cc )2, -SO2R cc , -SO2OR cc , -SOR aa , -C(=S)N(R cc )2, -C(=O)SR cc , -C(=S)SR cc , -P(=O)2R aa , -P(=O)(R aa )2, -P(=O)2N(R cc )2, -P(=O)(NR cc )2, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl, or two R cc groups attached to a nitrogen atom combine to form a heterocyclyl or heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd groups, and wherein Raa R bb R cc and R dd As described above.

[0107] Other definitions

[0108] As used herein, "biomolecule" includes, but is not limited to, a functional protein, enzyme, antigen, antibody, peptide, nucleic acid (e.g., mononucleotide or nucleoside, oligonucleotide, polynucleotide, and single and higher chain nucleic acids), lectin, receptor, or combinations thereof. Preferably, the biomolecule is a nucleic acid.

[0109] As used herein, unless otherwise indicated, a bivalent structure can be attached to the remainder of the compound in either direction, left to right or right to left. In one embodiment, the bivalent structure is preferably attached to the remainder of the compound in the left to right orientation.

[0110] The term "amino acid residue" means comprising any natural or synthetic amino acid residue, not limited to the amino acid residues in the group consisting of the 20 naturally occurring amino acids, wherein the residue refers to the moiety remaining after removal of water from an amino acid linked by a peptide bond. The 20 naturally occurring amino acid residues are selected from the group consisting of alanine (Ala or A), cysteine (Cys or C), aspartic acid (Asp or D), glutamic acid (Glu or E), phenylalanine (Phe or F), glycine (Gly or G), histidine (His or H), isoleucine (lie or I), lysine (Lys or K), leucine (Leu or L), methionine (Met or M), asparagine (Asn or N), proline (Pro or P), glutamine (Gin or Q), arginine (Arg or R), serine (Ser or S), threonine (Thr or T), valine (Val or V), tryptophan (Trp or W), and tyrosine (Tyr or Y) residues.

[0111] The term "pharmaceutically acceptable salt" as used herein means those carboxylate salts, amino acid addition salts of the compounds of the present application which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of patients without considerable toxic, irritating, allergic and like effects, commensurate with a reasonable benefit / risk ratio, effective for their intended use, including, where possible, the zwitterionic form of the compounds of the present application.

[0112] The present application includes tautomers, which are functional group isomers that result from the rapid movement of an atom in a molecule between two positions. Where a compound exists in different tautomeric forms, one said compound is not limited to any particular tautomer, but is intended to cover both tautomeric forms.

[0113] The compounds of the present application can include one or more asymmetric centers and can thus occur as various stereoisomeric forms, such as enantiomeric and / or diastereomeric forms. For example, the compounds of the present application can be individual enantiomers, diastereomers or geometric isomers (such as cis- and trans-isomers), or can be mixtures of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomer. Isomers can be separated by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts; or the preferred isomer can be prepared by asymmetric synthesis.

[0114] Those skilled in the art will appreciate that organic compounds can exist in solvated forms, in which the compound is complexed or coordinated with a solvent, usually water, but also including less polar solvents such as methanol, ethanol, acetic acid, DMSO, THF, ether, and the like. These solvated forms are equivalent to unsolvated forms. The present application encompasses both solvated and unsolvated forms of the compounds of the present application.

[0115] The term "solvate" refers to a form of a compound or salt thereof in combination with a solvent, usually formed by solvolysis. This physical association can include hydrogen bonding. Conventional solvents include water, methanol, ethanol, acetic acid, DMSO, THF, ether, and the like. The compounds described herein can be prepared as, and isolated as, a solvate. Suitable solvates include pharmaceutically acceptable solvates and further include stoichiometric solvates and non-stoichiometric solvates. In some cases, the solvate will be capable of isolation, for example, where one or more solvent molecules are incorporated into the crystal lattice of the solid state form of the compound. "Solvate" includes both solution-phase solvates and isolatable solvates. Representative solvates include hydrates, ethanolates, and methanolates.

[0116] The term "hydrate" refers to a compound in combination with water. Typically, the ratio of water molecules to compound molecules in a hydrate of a compound is defined. Thus, a hydrate of a compound can be represented, for example, by the general formula R x H2O, where R is the compound, and x is a number greater than 0. A given compound can form more than one hydrate type, including, for example, monohydrates (x is 1), lower hydrates (x is a number greater than 0 and less than 1, for example, hemihydrates (R 0.5 H2O)), and polyhydrates (x is a number greater than 1, for example, dihydrates (R 2 H2O) and hexahydrates (R 6 H2O)).

[0117] The compounds of the present application can be in the amorphous or crystalline form (polymorphs). Furthermore, the compounds of the present application can exist in one or more crystalline forms. Accordingly, the present application includes within its scope all amorphous or crystalline forms of the compounds of the present application. The term "polymorph" refers to crystalline forms of a compound (or salts, hydrates or solvates thereof) that have the same elemental composition but different crystal packing arrangements. All polymorphs of a compound have the same elemental makeup. Different polymorphs of a compound often have different X-ray diffraction patterns, infrared spectra, melting points, density, hardness, crystal shape, optical and electrical properties, stability, and solubility. The recrystallization solvent, the rate of crystallization, storage temperature, and other factors can cause one crystalline form to dominate over another. Various polymorphs of a compound can be prepared by crystallization under different conditions.

[0118] The present application also includes isotopically-labelled compounds (isotopic variants) which are identical to those recited in Formula (I) but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes that can be suitably substituted into the compounds of the present application include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, sulphur, fluorine, and chlorine, for example 2 H, 3 H, 13 C, 11 C, 14 C, 15 N, 18 O, 17 O, 31 P, 32 P, 35 S, 18 F, and 36 Cl. The present application includes within its scope prodrugs of the compounds of the present application, as well as the pharmaceutically acceptable salts of said compounds or of said prodrugs. Certain isotopically-labelled compounds of the present application, for example those into which radioactive isotopes such as 3 H, and 14 C, can be useful in drug and / or substrate tissue distribution assays. Tritiated, i.e., 3 H, and carbon-14, i.e., 14 C, isotopes are particularly preferred for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium, i.e., 2 H, can afford certain therapeutic advantages resulting from greater metabolic stability, such as increased in vivo half-life or reduced dosage requirements. Isotopically labelled compounds of Formula (I) of the present application and prodrugs thereof can generally be prepared by carrying out the procedures disclosed in the schemes and / or in the examples and BRIEF DESCRIPTION OF DRAWINGS

[0119] Figure 1 is a plot of tumor volume change in NCI-N87 xenograft mice after administration of representative antibody drug conjugates (ADC-51, ADC-52 and ADC-69) of the present application.

[0120] Figure 2 is a plot of body weight change in NCI-N87 xenograft mice after administration of representative antibody drug conjugates (ADC-51, ADC-52 and ADC-69) of the present application.

[0121] Figure 3 is a plot of tumor volume change in JIMT-1 xenograft mice after administration of representative antibody drug conjugates (ADC-40, ADC-63, ADC-72, ADC-78 and ADC-79) of the present application.

[0122] Figure 4 is a plot of body weight change in JIMT-1 xenograft mice after administration of representative antibody drug conjugates (ADC-40, ADC-63, ADC-72, ADC-78 and ADC-79) of the present application.

[0123] Figure 5 is the stability of representative antibody drug conjugates (ADC-1, ADC-2, ADC-14, ADC-16, ADC-19 and ADC-20) of the present application in human plasma.

[0124] Figure 6 is the stability of representative antibody drug conjugates (ADC-1, ADC-2, ADC-14, ADC-16, ADC-19 and ADC-20) of the present application in monkey plasma. DETAILED DESCRIPTION

[0125] As used herein, "a compound described herein" refers to a compound of Formula (D) and the like (and sub-generic compounds thereof, such as Formula (D-1), Formula (D-2), Formula (D-3) or Formula (D-4), and the like) or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof.

[0126] As used herein, compounds are named using standard nomenclature. Compounds having asymmetric centers should be understood as encompassing all optical isomers and mixtures thereof, unless otherwise indicated. In addition, unless otherwise indicated, all isomeric compounds included in the present application are meant to include Z and E forms of carbon-carbon double bonds. Where compounds exist in different tautomeric forms, one compound is not intended to exclude the other tautomeric form(s).

[0127] I. Compounds and conjugates of the present application

[0128] 1.1 Compounds of Formula (D)

[0129] In one embodiment, the present application relates to a compound of Formula (D), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0130] wherein,

[0131] * is a chiral center selected from the (S) or (R) absolute configuration, or mixtures thereof;

[0132] A1is selected from -C 0-6 alkylene-OH, -C 0-6 alkylene-NH2, or -C 0-6 alkylene-SH;

[0133] A2is selected from -(CR a R b ) k - or -(CR a R b ) k -O-(CR a R b ) k -;

[0134] R a and R b are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or C 1-6 haloalkoxy;

[0135] Alternatively, two R a on two different carbon atoms are joined together to form, together with the carbon atoms to which they are attached, a C 3-10 cycloalkylene, 3-10 membered heterocyclylene, C 6-10 arylene, or 5-10 membered heteroarylene;

[0136] k is 2, 3, 4, 5, or 6;

[0137] A3is selected from -C 0-6 alkylene-NH-C 0-6 alkylene-, -C 0-6 alkylene-C(O)-C 0-6 alkylene-, -C 0-6 alkylene-NHC(O)-C 0-6 alkylene-, -C 0-6 alkylene-C(O)NH-C 0-6 alkylene-, -C 0-6 alkylene-NHC(O)O-C 0-6alkylene- or -C 0-6 alkylene-NHC(O)NH-C 0-6 alkylene-;

[0138] A1, A2and A3are optionally substituted with 1, 2, 3, 4 or 5 R A , as chemically allowed;

[0139] R1and R2are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0140] or R1and R2, or the carbon atom to which R2is attached, are connected to form a C 5-10 cycloalkyl, 5-10 membered heterocyclyl, C 6-10 aryl or 5-10 membered heteroaryl;

[0141] R1, R2and the ring formed by R1and R2are optionally substituted with 1, 2, 3, 4 or 5 R B ;

[0142] R3and R4are independently selected from halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0143] or R3and R4are connected to form, together with the carbon atom to which both are attached, a C 4-10 cycloalkyl, 4-10 membered heterocyclyl, C 6-10 aryl or 5-10 membered heteroaryl;

[0144] R3, R4and the ring formed by R3and R4are optionally substituted with 1, 2, 3, 4 or 5 R C ;

[0145] R5is selected from -NH2or -OH, preferably OH;

[0146] R6is selected from C 3-10 cycloalkyl, 3-10 membered heterocyclyl, C 6-10 aryl, 5-10 membered heteroaryl, -C 1-6 alkylene-C 3-10 cycloalkyl, -C 1-6 alkylene-3-10 membered heterocyclyl, -C 1-6 alkylene-C 6-10 aryl or -C 1-6 alkylene-5-10 membered heteroaryl, preferably -C1-6 alkylene-C 3-10 cycloalkyl;

[0147] R6is optionally substituted with 1, 2, 3, 4, or 5 R D substituents;

[0148] each R A , R B , R C , and R D is independently selected from deuterium, halogen, -C 0-6 alkylene-OH, -C 0-6 alkylene-CN, -C 0-6 alkylene-NH2, C 1-6 alkyl, -C 0-6 alkylene-C 1-6 alkoxy, -C 0-6 alkylene-C 1-6 haloalkyl, -C 0-6 alkylene-C 1-6 haloalkoxy, -C 0-6 alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10 membered heterocyclyl, -C 0-6 alkylene-C 6-10 aryl, or -C 0-6 alkylene-5-10 membered heteroaryl.

[0149] *, *1, *2, and *3

[0150] In one embodiment, * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof.

[0151] In one embodiment, *1 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof.

[0152] In one embodiment, *2 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof.

[0153] In one embodiment, *3 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof.

[0154] A1

[0155] In one embodiment, A1is -C 0-6 alkylene-OH; in another embodiment, A1is -C 0-6 alkylene-NH2; in another embodiment, A1is -C 0-6 alkylene-SH.

[0156] In a particular embodiment, A1is -OH; in another embodiment, A1is -CH2OH; in another particular embodiment, A1is -NH2; in another embodiment, A1is -CH2NH2; in another embodiment, A1is -SH; in another embodiment, A1is -CH2SH.

[0157] A2

[0158] In one embodiment, A2is -(CR a R b ) k -; in another embodiment, A2is -(CR a R b ) k -O-(CR a R b ) k -.

[0159] R a and R b

[0160] In one embodiment, R a is H; in another embodiment, R a is halogen; in another embodiment, R a is CN; in another embodiment, R a is OH; in another embodiment, R a is NH2; in another embodiment, R a is C 1-6 alkyl; in another embodiment, R a is C 1-4 alkyl; in another embodiment, R a is C 1-6 alkoxy; in another embodiment, R a is C 1-6 haloalkyl; in another embodiment, R a is C 1-6 haloalkoxy.

[0161] In one embodiment, two R a on two different carbon atoms are joined together to form, together with the carbon atoms to which they are attached, a C 3-10 cycloalkylene; in another embodiment, two R a on two different carbon atoms are joined together to form, together with the carbon atoms to which they are attached, a C 3-7 cycloalkylene, preferably a C 3-5 cycloalkylene, such as cyclopropyl; in another embodiment, two Ra are attached, together with the carbon atom to which they are attached, form a 3-10 membered heterocyclylenyl group, for example a 3-7 membered heterocyclylenyl group; in another embodiment, two R a are attached, together with the carbon atom to which they are attached, form a C 6-10 arylene group; in another embodiment, two R a are attached, together with the carbon atom to which they are attached, form a 5-10 membered heteroarylenyl group.

[0162] In one embodiment, R b is H; in another embodiment, R b is halogen; in another embodiment, R b is CN; in another embodiment, R b is OH; in another embodiment, R b is NH2; in another embodiment, R b is C 1-6 alkyl; in another embodiment, R b is C 1-4 alkyl; in another embodiment, R b is C 1-6 alkoxy; in another embodiment, R b is C 1-6 haloalkyl; in another embodiment, R b is C 1-6 haloalkoxy.

[0163] In one embodiment, R a and R b are not simultaneously H.

[0164] In one embodiment, R a is not H, and R b is H.

[0165] k and k’

[0166] In one embodiment, k is 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2.

[0167] In one embodiment, k’ is 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 1, 2 or 3, more preferably 1.

[0168] A3

[0169] In one embodiment, A3 is -C 0-6 alkylene-NH-C 0-6alkylene-; in another embodiment, A3 is -C 0-6 alkylene-C(O)-C 0-6 alkylene-; in another embodiment, A3 is -C 0-6 alkylene-NHC(O)-C 0-6 alkylene-; in another embodiment, A3 is -C 0-6 alkylene-C(O)NH-C 0-6 alkylene-; in another embodiment, A3 is -C 0-6 alkylene-NHC(O)O-C 0-6 alkylene-; in another embodiment, A3 is -C 0-6 alkylene-NHC(O)NH-C 0-6 alkylene-.

[0170] In a particular embodiment, A3 is -NH-; in another particular embodiment, A3 is -C(O)-; in another particular embodiment, A3 is -NHC(O)-; in another particular embodiment, A3 is -C(O)NH-.

[0171] A1-A2-A3-

[0172] In a particular embodiment, A1-A2-A3- is selected from

[0173] In a particular embodiment, A1, A2, and A3 are unsubstituted; in another particular embodiment, A1, A2, or A3 is optionally substituted with 1, 2, 3, 4, or 5 R A , as chemically allowed.

[0174] R1and R2

[0175] In one embodiment, R1is H; in another embodiment, R1is halogen; in another embodiment, R1is CN; in another embodiment, R1is OH; in another embodiment, R1is NH2; in another embodiment, R1is C 1-6 alkyl; in another embodiment, R1is C 1-6 alkoxy; in another embodiment, R1is C 1-6 haloalkyl; in another embodiment, R1is C 1-6 haloalkoxy.

[0176] H; in another embodiment, R2is halogen; in another embodiment, R2is CN; in another embodiment, R2is OH; in another embodiment, R2is NH2; in another embodiment, R2is C 1-6 alkyl; in another embodiment, R2is C 1-6 alkoxy; in another embodiment, R2is C 1-6 haloalkyl; in another embodiment, R2is C 1-6 haloalkoxy.

[0177] In one embodiment, R1and R2, or the carbon atom to which R2is attached, are joined to form a C 5-10 cycloalkyl, preferably a C 5-7 cycloalkyl, for example, cyclohexyl; in another embodiment, R1and R2, or the carbon atom to which R2is attached, are joined to form a 5-10 membered heterocyclyl, for example, a 5-7 membered heterocyclyl; in another embodiment, R1and R2, or the carbon atom to which R2is attached, are joined to form a C 6-10 aryl; in another embodiment, R1and R2, or the carbon atom to which R2is attached, are joined to form a 5-10 membered heteroaryl.

[0178] In one embodiment, R1, R2, and the ring formed by R1and R2are unsubstituted; in another embodiment, R1, R2, or the ring formed by R1and R2is optionally substituted with 1, 2, 3, 4, or 5 R B substituents.

[0179] R3and R4

[0180] In one embodiment, R3is halogen; in another embodiment, R3is CN; in another embodiment, R3is OH; in another embodiment, R3is NH2; in another embodiment, R3is C 1-6 alkyl; in another embodiment, R3is C 1- 6alkoxy; in another embodiment, R3is C 1-6 haloalkyl; in another embodiment, R3is C 1-6 haloalkoxy.

[0181] In one embodiment, R4is halogen; in another embodiment, R4is CN; in another embodiment, R4is OH; in another embodiment, R4is NH2; in another embodiment, R4is C 1-6 alkyl; in another embodiment, R4is C 1- 6alkoxy; in another embodiment, R4is C 1-6haloalkyl; in another embodiment, R4 is C 1-6 haloalkyl; in another embodiment, R4 is C

[0182] in one embodiment, R3 and R4 are joined to form, together with the carbon atom to which they are attached, a C 3-10 cycloalkyl; in another embodiment, R3 and R4 are joined to form, together with the carbon atom to which they are attached, a 3-10 membered heterocyclyl; in another embodiment, R3 and R4 are joined to form, together with the carbon atom to which they are attached, a C 6-10 aryl; in another embodiment, R3 and R4 are joined to form, together with the carbon atom to which they are attached, a 5-10 membered heteroaryl.

[0183] in one preferred embodiment, R3 is C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl.

[0184] in one preferred embodiment, R4 is halogen, preferably F.

[0185] in one embodiment, R3, R4 or the ring formed by R3 and R4 is unsubstituted; in another embodiment, R3, R4 or the ring formed by R3 and R4 is optionally substituted with 1, 2, 3, 4 or 5 R C substituted.

[0186] R5

[0187] in one embodiment, R5 is -NH2; in another embodiment, R5 is -OH.

[0188] R6

[0189] in one embodiment, R6 is C 3-10 cycloalkyl; in another embodiment, R6 is 3-10 membered heterocyclyl; in another embodiment, R6 is C 6-10 aryl; in another embodiment, R6 is 5-10 membered heteroaryl; in another embodiment, R6 is -C 1-6 alkylene-C 3-10 cycloalkyl; in another embodiment, R6 is -C 1-6 alkylene-3-10 membered heterocyclyl; in another embodiment, R6 is -C 1-6 alkylene-C 6-10 aryl; in another embodiment, R6 is -C 1-6 alkylene-5-10 membered heteroaryl

[0190] in one preferred embodiment, R6 is -C 1-6 alkylene-C 3-10cycloalkyl, more preferably -CH2-cyclopropyl. 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl.

[0191] In one embodiment, R6is optionally substituted with 1, 2, 3, 4, or 5 R D substituted.

[0192] Ring A and Ring B

[0193] In one embodiment, Ring A is C 3-10 cycloalkylene, for example C 3-7 cycloalkylene; in another embodiment, Ring A is 3-10 membered heterocyclylidenyl, for example 3-7 membered heterocyclylidenyl; in another embodiment, Ring A is C 6-10 arylene; in another embodiment, Ring A is 5-10 membered heteroarylenyl.

[0194] In one preferred embodiment, Ring A is C 3-7 cycloalkylene, preferably C 3-5 cycloalkylene, for example cyclobutylidene.

[0195] In one embodiment, Ring B is C 3-10 cycloalkylene, for example C 3-7 cycloalkylene; in another embodiment, Ring B is 3-10 membered heterocyclylidenyl, for example 3-7 membered heterocyclylidenyl; in another embodiment, Ring B is C 6-10 arylene; in another embodiment, Ring B is 5-10 membered heteroarylenyl.

[0196] In one preferred embodiment, Ring B is C 3-7 cycloalkyl, preferably C 3-5 cycloalkyl, for example cyclopropyl.

[0197] R A , R B , R C , and R D

[0198] In one embodiment, each R A is independently selected from deuterium, halogen, -C 0-6 alkylene-OH, -C 0-6 alkylene-CN, -C 0-6 alkylene-NH2, C 1-6 alkyl, -C 0-6 alkylene-C 1-6 alkoxy, -C 0-6 alkylene-C 1-6 haloalkyl, -C 0-6 alkylene-C1-6 Halogenated alkoxy groups, -C 0-6 Alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10-membered heterocyclic group, -C 0-6 Alkylene-C 6-10 Aryl or -C 0-6 Alkylene-5-10-membered heteroaryl.

[0199] In one implementation scheme, each R B Independently selected from deuterium, halogens, and -C 0-6 alkylene -OH, -C 0-6 Alkylene-CN, -C 0-6 Alkylene-NH2, C 1-6 Alkyl, -C 0-6 Alkylene-C 1-6 Alkoxy, -C 0-6 Alkylene-C 1-6 Halogenated alkyl, -C 0-6 Alkylene-C 1-6 Halogenated alkoxy groups, -C 0-6 Alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10-membered heterocyclic group, -C 0-6 Alkylene-C 6-10 Aryl or -C 0-6 Alkylene-5-10-membered heteroaryl.

[0200] In one implementation scheme, each R C Independently selected from deuterium, halogens, and -C 0-6 alkylene -OH, -C 0-6 Alkylene-CN, -C 0-6 Alkylene-NH2, C 1-6 Alkyl, -C 0-6 Alkylene-C 1-6 Alkoxy, -C 0-6 Alkylene-C 1-6 Halogenated alkyl, -C 0-6 Alkylene-C 1-6 Halogenated alkoxy groups, -C 0-6 Alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10-membered heterocyclic group, -C 0-6 Alkylene-C 6-10 Aryl or -C 0-6 Alkylene-5-10-membered heteroaryl.

[0201] In one implementation scheme, each R D Independently selected from deuterium, halogens, and -C 0-6alkylene-OH, -C 0-6 alkylene-CN, -C 0-6 alkylene-NH2, C 1-6 alkyl, -C 0-6 alkylene-C 1-6 alkoxy, -C 0-6 alkylene-C 1-6 haloalkyl, -C 0-6 alkylene-C 1-6 haloalkoxy, -C 0-6 alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10 membered heterocyclyl, -C 0-6 alkylene-C 6-10 aryl or -C 0-6 alkylene-5-10 membered heteroaryl.

[0202] Any of the technical solutions in any of the above specific embodiments or any combination thereof can be combined with any of the technical solutions in other specific embodiments or any combination thereof. For example, any of the technical solutions of Al or any combination thereof can be combined with any of the technical solutions of A2, A3, R1, R2, R3, R4, R5, R6, k, ring A, ring B, R A , R B , R C , R D , *, *1 to *3, etc. or any combination thereof. The present application is intended to include all combinations of these technical solutions, which are not listed one by one due to the limited space.

[0203] In more specific embodiments, the present application relates to the above-mentioned compounds of formula (D), wherein,

[0204] * is a chiral center selected from (S) or (R) absolute configuration, or a mixture thereof;

[0205] A1is selected from -OH, -CH2OH, -NH2, -CH2NH2, -SH or -CH2SH;

[0206] A2is -(CR a R b ) k -;

[0207] R a and R b are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-6 alkyl;

[0208] Alternatively, two R atogether with the carbon atom to which they are attached form C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0209] k is 2, 3 or 4;

[0210] A3is selected from -NH-, -C(O)-, -NHC(O)- or -C(O)NH-;

[0211] A1-A2-A3- can optionally be further substituted by 1, 2 or 3 substituents selected from halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, C 1-6 haloalkoxy;

[0212] R1and R2are independently selected from H, C 1-6 alkyl, C 1-6 haloalkyl, C 1-6 alkoxy or C 1-6 haloalkoxy;

[0213] or R1and R2, or the carbon atom to which R2is attached, are linked to form C 5-7 cycloalkyl or 5-7 membered heterocyclyl;

[0214] R3and R4are independently selected from halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0215] or R3and R4, or the carbon atom to which R4is attached, are linked to form C 4-10 cycloalkyl or 4-10 membered heterocyclyl;

[0216] R5is OH;

[0217] R6is selected from -C 1-6 alkylene-C 3-7 cycloalkyl or -C 1-6 alkylene-3-7 membered heterocyclyl.

[0218] In more specific embodiments, the present application relates to compounds of formula (D) as described above, wherein

[0219] * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0220] A1-A2-A3- is selected from

[0221] A1-A2-A3- is optionally substituted with 1, 2, or 3 substituents selected from the group consisting of halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, C 1-6 haloalkoxy, further substituted with 1, 2, or 3 substituents selected from the group consisting of halogen, CN, OH, NH2, C

[0222] R1and R2are independently selected from H or C 1-6 alkyl;

[0223] or R1and R2, or the carbon atom to which R2is attached, are joined to form a C 5-7 cycloalkyl, preferably a six-membered cycloalkyl;

[0224] R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl;

[0225] R4is selected from halogen, OH, NH2, or C 1-6 alkyl, preferably halogen, more preferably F;

[0226] R5is OH;

[0227] R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl.

[0228] In more specific embodiments, the present application relates to the above-mentioned compounds of formula (D), wherein said compounds have the structure of formula (D-1), formula (D-2), formula (D-3), or formula (D-4):

[0229] wherein,

[0230] *1, *2, *3 are chiral centers independently selected from (S) or (R) absolute configuration, or a mixture thereof;

[0231] Ring A is selected from C 3-10 cycloalkylene, 3-10 membered heterocyclylene, C 6-10 arylene, or 5-10 membered heteroarylene;

[0232] Ring B is selected from C 3-10 cycloalkyl, 3-10 membered heterocyclyl, C 6-10 aryl, or 5-10 membered heteroaryl;

[0233] the other variables are as defined herein.

[0234] In more specific embodiments, the present application relates to the above-mentioned compounds of formula (D), wherein said compounds have the structure of formula (D-1) or formula (D-2):

[0235] wherein,

[0236] *1 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0237] *2 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0238] *3 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0239] A1 is selected from -OH, -CH2OH, -NH2, -CH2NH2, -SH or -CH2SH, preferably -OH or -CH2OH;

[0240] R a and R b are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0241] R3 is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl;

[0242] R4 is selected from halogen, OH or C 1-6 alkyl;

[0243] or R3 and R4, taken together with the carbon atom to which they are attached, form a C 3-7 cycloalkyl or 3-7 membered heterocyclyl;

[0244] Ring B is selected from C 3-7 cycloalkyl or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkyl;

[0245] Preferably, in formula (D-2), R a and R b are preferably not both H;

[0246] Preferably, R b is preferably H;

[0247] More preferably,

[0248] *1 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0249] *2 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof, preferably the (R) absolute configuration;

[0250] *3 is a chiral center, selected from (S) or (R) absolute configuration, or a mixture thereof, preferably (S) absolute configuration;

[0251] A1is selected from -OH, -CH2OH, -NH2, or -CH2NH2, preferably -OH or -CH2OH;

[0252] R a is selected from H or C 1-4 alkyl, for example H or methyl; when R a is not H, *1 is preferably in (S) or (R) configuration, and *2 is preferably in (R) absolute configuration;

[0253] R b is independently selected from H or C 1-4 alkyl, for example H or methyl, preferably H;

[0254] In formula (D-2), R a and R b are preferably not both H;

[0255] R3is C 1-6 alkyl, preferably C 1-4 alkyl, for example methyl;

[0256] R4is halogen, preferably F;

[0257] Ring B is C 3-7 cycloalkyl, preferably C 3-5 cycloalkyl, for example cyclopropyl.

[0258] In more specific embodiments, the present application relates to the above-mentioned compounds of formula (D) having the above-mentioned structure of formula (D-1), wherein R b is H, i.e. the carbon atom to which R b is attached does not have chirality, so that formula (D-1) also comprises the structure of formula (D-1a).

[0259] In specific embodiments, the present application relates to the above-mentioned compounds of formula (D) having the above-mentioned structure of formula (D-1), (D-2), (D-3), (D-4), (D-1a), wherein, when described as "*1, *2, *3 are chiral centers", both the case when R a or R b is not H, *1, *2, *3 are chiral centers, independently selected from (S) or (R) absolute configuration, or a mixture thereof; and the case when R a or R b are each independently H, in which case *1, *2, *3 are not chiral.

[0260] In more particular embodiments, the present application relates to the above-mentioned compounds of formula (D), wherein said compounds have the structure of formula (D-3) or formula (D-4):

[0261] wherein,

[0262] *1 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0263] A1 is selected from -OH, -CH2OH, -NH2, -CH2NH2, -SH or -CH2SH, preferably -OH or -CH2OH;

[0264] Ring A is selected from C 3-7 cycloalkylene or 3-7 membered heterocyclylene, preferably C 3-7 cycloalkylene;

[0265] R3 is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl;

[0266] R4 is selected from halogen, OH or C 1-6 alkyl;

[0267] or R3 and R4 are linked together with the carbon atom to which they are attached to form a C 3-7 cycloalkyl or 3-7 membered heterocyclyl;

[0268] Ring B is selected from C 3-7 cycloalkyl or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkyl;

[0269] Preferably,

[0270] *1 is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0271] A1 is selected from -OH, -CH2OH, -NH2 or -CH2NH2, preferably -OH;

[0272] Ring A is C 3-7 cycloalkylene, preferably C 3-5 cycloalkylene, such as cyclobutylene;

[0273] R3 is C 1-6 alkyl, preferably C 1-4 alkyl, such as methyl;

[0274] R4 is halogen, preferably F;

[0275] Ring B is C 3-7 cycloalkyl, preferably C3-5 Cycloalkyl, for example cyclopropyl.

[0276] In more particular embodiments, the present application relates to the following compounds 1-21, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0277] 1.2 Linker-drug conjugates

[0278] In one embodiment, the present application relates to a linker-drug conjugate selected from the group consisting of compounds of formula (LD), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0279] L1— L2— L3— D (LD)

[0280] wherein,

[0281] D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity;

[0282] L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0283] L 1a is a thiol reactive group, for example

[0284] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; optionally 1, 2 or 3 non-adjacent carbon atoms of said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced by a heteroatom of O, S, N, while each -CH2- of C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted by 1 or 2 R 1a ;

[0285] each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1amay be connected to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0286] L 1b optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0287] L 1c is selected from a bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0288] L 1d is selected from a bond, C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene, any 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced with a heteroatom of O, S, N, and each -CH2- in said C 1-10 alkylene, C 2- 10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1c ;

[0289] each R 1c is independently selected from H, halogen, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0290] n is selected from 1, 2, 3, 4, 5, or 6;

[0291] L 1c and L 1d may simultaneously be a bond;

[0292] L 1e is selected from -C(O)-, -NHC(O)-, or -C(O)-NHC(O)-;

[0293] L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valine (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0294] L3is an optionally substituted or unsubstituted spacer.

[0295] L1

[0296] In one embodiment, L1is L 1a -L 1b -L 1c -L 1d -L 1e -.

[0297] In one particular embodiment, L1is

[0298] In one more particular embodiment, L1is:

[0299] m, w and n

[0300] In one embodiment, each m is independently selected from 1, 2, 3, 4, 5 or 6.

[0301] In one embodiment, each w is independently selected from 1, 2, 3, 4, 5 or 6.

[0302] In one embodiment, each n is independently selected from 1, 2, 3, 4, 5 or 6.

[0303] R 1a and R 1a’

[0304] In one embodiment, each R 1a is independently selected from H, halo, C 1-6 alkyl or C 1-6 haloalkyl.

[0305] In one embodiment, each R 1a’ is independently selected from H, halo, C 1-6 alkyl or C 1-6 haloalkyl.

[0306] In one embodiment, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene, preferably a C 3-5 cycloalkylene or 3-5 membered heterocyclylene.

[0307] L 1a

[0308] In one embodiment, L 1a is a thiol reactive group; in another embodiment, L 1a is In another embodiment, L 1a is

[0309] L 1b

[0310] In one embodiment, L 1b is C 1-10 alkylene; in another embodiment, L 1b is C 2-10 alkenylene; in another embodiment, L 1b is C 2-10 alkynylene; in another embodiment, the aforementioned C 1-10 alkylene, C2-10 imide or C 2-10 Any one, two, or three non-adjacent carbon atoms in the ynynyl group may optionally be replaced by heteroatoms of O, S, or N; in another embodiment, the aforementioned C 1-10 Alkylene, C 2-10 imide or C 2-10 Each -CH2- in the ynylene group is optionally surrounded by one or two R groups. 1a replace.

[0311] In one implementation, L 1b C 1-8 Alkylene; in another embodiment, L 1b -(CH2CH2O) w -C 1-4 alkylene-; in another embodiment, L 1b C 2-8 alkenyl; in another embodiment, L 1b C 2-8 Idemynyl; in another embodiment, the above C 1-8 Alkylene, -(CH2CH2O) w -C 1-4 Alkylene-, C 2-8 imide or C 2-8 Each -CH2- in the ynylene group is optionally surrounded by one or two R groups. 1a replace;

[0312] In one implementation, L 1b Not replaced; in another implementation, L 1b Replaced by a hydrophilic group; in another embodiment, the hydrophilic group is selected from: In another implementation, L 1b Replaced by a hydrophilic group, the hydrophilic group being selected from:

[0313] In a preferred embodiment, L 1b At least one of -CH2- in it is affected by one or two R 1a replace.

[0314] In a preferred embodiment, each R 1a Independently selected from halogens, C 1-6 Alkyl or C 1-6 Haloalkyl. Or, two R atoms on any same or different carbon atoms. 1a Connection forms C 3-10 Cycloalkyl or 3-10 membered heterocyclic groups.

[0315] In a preferred embodiment, L 1b is substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene.

[0316] R 1b and R 1b’

[0317] In one embodiment, R 1b is H; in another embodiment, R 1b is C 1-6 alkyl; in another embodiment, R 1b is C 1-6 haloalkyl.

[0318] In one embodiment, R 1b’ is H; in another embodiment, R 1b’ is C 1-6 alkyl; in another embodiment, R 1b’ is C 1-6 haloalkyl.

[0319] In one embodiment, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene, for example C 3-7 cycloalkylene or 3-7 membered heterocyclylene.

[0320] L 1c

[0321] In one embodiment, L 1c is a bond; in another embodiment, L 1c is -C(O)-; in another embodiment, L 1c is -C(O)NH-; in another embodiment, L 1c is -NHC(O)-.

[0322] L 1d

[0323] In one embodiment, L 1d is a bond; in another embodiment, L 1d is C 1-10 alkylene; in another embodiment, L 1d is C 2-10 alkenylene; in another embodiment, L 1d is C2-10 alkynylene; in another embodiment, the C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1c groups.

[0324] In one embodiment, L 1d is a bond; in another embodiment, L 1d is C 1-8 alkylene or -(CH2CH20) w -C 1-4 alkylene-; in another embodiment, L 1d is the C 1-8 alkylene optionally substituted with -NHC(O)-(CH2CH20) n -C 1-4 alkyl or -C(O)NH-(CH2CH20) n -C 1-4 alkyl.

[0325] In one embodiment, L 1c and L 1d are simultaneously a bond.

[0326] R 1c

[0327] In one embodiment, each R 1c is independently selected from H, halo, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1-4 alkylene) n -C1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; in another embodiment, two R 1c may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl, preferably C 3-7 cycloalkylene or 3-7 membered heterocyclyl, more preferably C 3-5 cycloalkylene, such as cyclopropylene.

[0328] L 1e

[0329] In one embodiment, L 1e is -C(O)-; in another embodiment, L 1e is -NHC(O)-; in another embodiment, L 1e is -C(O)-NHC(O)-.

[0330] L2

[0331] In one embodiment, L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of one another, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine.

[0332] In one particular embodiment, L2is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, preferably each amino acid residue is independently selected from glycine, phenylalanine and alanine, more preferably -GlyGlyPheGly- or -AlaAlaAla-.

[0333] In one particular embodiment, each amino acid residue in said L2is optionally substituted with 1, 2 or 3 R 2a groups.

[0334] In one embodiment, L2 is: L2 is attached at end a to L1 and at end b to L3.

[0335] R 2a

[0336] In one embodiment, each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3 or OCH3.

[0337] L3

[0338] In one embodiment, L3 is an optionally substituted or unsubstituted spacer.

[0339] In one embodiment, L3 is -NH-CH2-(AM); in another embodiment, L3 is (PABC).

[0340] In one embodiment, the L3 is unsubstituted, in another embodiment, the L3 is optionally substituted with 1, 2 or 3 R 3a .

[0341] R 3a

[0342] In one embodiment, R 3a is H; in another embodiment, R 3a is C 1-6 alkyl; in another embodiment, R 3a is C 1- 6alkoxy; in another embodiment, R 3a is C 1-6 haloalkyl; in another embodiment, R 3a is C 1-6 haloalkoxy.

[0343] D

[0344] In one embodiment, D is a biologically active fragment; in another embodiment, D is a molecular fragment having anti-tumor biological activity; in another embodiment, D is a DNA topoisomerase I inhibitor; in another embodiment, D is a camptothecin derivative.

[0345] In one embodiment, D is derived from a monovalent radical of a compound of Formula (D) as described herein, or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof.

[0346] In one embodiment, D is a compound of Formula (D’), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof:

[0347] wherein,

[0348] A1’ is selected from -O-C 0-6 alkylene-, -NH-C 0-6 alkylene-, or -S-C 0-6 alkylene-;

[0349] each variable is as defined herein.

[0350] In one specific embodiment, D is selected from a monovalent radical derived from a compound of Formula (D’), Formula (D-1’), Formula (D-2’), Formula (D-3’), or Formula (D-4’), (D-5’), (D-6’), wherein each variable is as defined herein.

[0351] In one specific embodiment, D is selected from a monovalent radical derived from a compound of Formula (D’), Formula (D-1’), Formula (D-2’), Formula (D-3’), or Formula (D-4’), (D-5’), (D-6’), wherein each variable is as defined herein.

[0352] Any of the above specific embodiments, or any combination thereof, can be combined with any of the other specific embodiments, or any combination thereof. For example, any of the embodiments of L1, or any combination thereof, can be combined with any of the embodiments of L2, L3, L 1a , L 1b , L 1c , L 1d , L 1e , D, etc., or any combination thereof. The present application is intended to include all such combinations of embodiments, which are limited in number only by the number of embodiments described herein.

[0353] In one embodiment, the present application relates to a linker-drug conjugate of Formula (LD) as described above, wherein D is derived from a monovalent radical of a compound of Formula (D) as described herein, or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof;

[0354] Preferably, D is a compound of Formula (D’), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or a mixture thereof:

[0355] wherein,

[0356] A1’ is selected from -O-C 0-6 alkylene-, -NH-C 0-6 alkylene-, or -S-C 0-6 alkylene-;

[0357] each variable is as defined herein.

[0358] In a more specific embodiment, the present application relates to the linker-drug conjugate of the above Formula (LD), wherein L 1b or L 1d C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally replaced by a heteroatom of O, S, N at any 1, 2, or 3 non-adjacent carbon atoms.

[0359] In a more specific embodiment, the present application relates to the linker-drug conjugate of the above Formula (LD), wherein two R 1a together form a C 3-10 cycloalkyl or 3-10 membered heterocyclyl.

[0360] In a more specific embodiment, the present application relates to the linker-drug conjugate of the above Formula (LD), wherein L 1b is substituted with a hydrophilic group R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene.

[0361] In a more specific embodiment, the present application relates to the linker-drug conjugate of the above Formula (LD), wherein:

[0362] L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0363] L 1a is

[0364] L 1bselected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; each -CH2- in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1a ;

[0365] each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be linked to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0366] L 1b is optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0367] L 1c is selected from a bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0368] L 1d is selected from a bond, C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene, said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene, any 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2- 10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1c ;

[0369] each R 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl;

[0370] L 1c and L 1d may simultaneously be a bond;

[0371] L 1eselected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0372] L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or unnatural amino acid residues, each of said amino acid residues being the same or different and independently of each other selected from the group consisting of residues of the amino acids alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (Ile), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine, preferably L2is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine;

[0373] each amino acid residue in L2is optionally substituted with 1, 2 or 3 R 2a ;

[0374] each R 2a is independently selected from halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0375] L3is an optionally substituted or unsubstituted spacer,

[0376] with the proviso that the linker-drug conjugate at least meets one of the following conditions:

[0377] 1) at least one -CH2- in L 1b is substituted with 1 or 2 R 1a ;

[0378] each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or two R 1a on any identical or different carbon atom can be linked to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0379] 2) L 1bsubstituted with a hydrophilic group selected from: R 1b R 1b’ and the carbon atom to which they are attached together form a C 3- 7 cycloalkylene or 3-7 membered heterocyclylene;

[0380] 3) at least one amino acid residue in said L2 is substituted with 1, 2, or 3 R 2a ;

[0381] each R 2a is independently selected from halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or C 1-6 haloalkoxy;

[0382] Preferably,

[0383] L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0384] L 1a is

[0385] L 1b is C 1-8 alkylene; at least one -CH2- in said C 1-8 alkylene is substituted with 1 or 2 R 1a ;

[0386] each R 1a is independently selected from halogen or C 1-6 alkyl; or, two R 1a on any identical or different carbon atom can join to form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene, preferably C 3-7 cycloalkylene;

[0387] L 1b is optionally substituted with a hydrophilic group selected from: R 1b R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0388] L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-;

[0389] L1d a chemical bond or C 1-8 alkylene, said C 1-8 alkylene optionally has 1, 2, or 3 non-adjacent carbon atoms replaced by a heteroatom of O, S, N, while said C 1-8 each -CH2- in said alkylene is optionally replaced by 1 or 2 R 1c substituents;

[0390] each R 1c is independently selected from H, halogen, or C 1-6 alkyl;

[0391] L 1c and L 1d may simultaneously be a chemical bond, L 1c and L 1d are preferably a chemical bond;

[0392] L 1e is selected from -C(O)- or -NHC(O)-, preferably -C(O)-;

[0393] L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine, and alanine;

[0394] each amino acid residue in said L2 is optionally substituted by 1, 2, or 3 R 2a substituents;

[0395] each R 2a is independently selected from halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or C 1-6 haloalkoxy;

[0396] L3 is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-;

[0397] said L3 is optionally substituted by 1, 2, or 3 R 3a substituents;

[0398] said R 3a is selected from H, C 1-6 alkyl, or C 1-6 haloalkyl;

[0399] with the proviso that said linker-drug conjugate at least meets one of the following conditions:

[0400] 1) L 1b has at least one -CH2- replaced by 1 or 2 R 1a substituents;

[0401] each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a groups on the same or different carbon atoms are joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0402] 2) L 1b is substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3- 7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0403] 3) at least one amino acid residue in said L2is substituted with 1, 2, or 3 R 2a ;

[0404] each R 2a is independently selected from halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy.

[0405] In a more particular embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein:

[0406] D is derived from a monovalent radical of a compound of formula (D) as described herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof, for example, selected from a compound of formula (D’) as described herein;

[0407] L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0408] L 1a is

[0409] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; said C 1-10 alkylene, C 2-10 alkenylene or C 2-10any 1, 2, or 3 non-adjacent carbon atoms in the alkylene, alkenylene, or alkynylene is optionally replaced with a heteroatom of O, S, or N, while C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkylene, alkenylene, or alkynylene is optionally replaced with a heteroatom of O, S, or N, while C 1a substituted;

[0410] each R 1a is independently selected from H, halogen, C 1-6 alkyl, or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be joined to form a C 3-10 cycloalkylene, or 3-10 membered heterocyclyl;

[0411] L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-;

[0412] L 1d is selected from a chemical bond, C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, said C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally replaced with a heteroatom of O, S, or N, while C 1-10 alkylene, C 2- 10 alkenylene, or C 2-10 alkynylene is optionally replaced with a heteroatom of O, S, or N, while C 1c substituted;

[0413] each R 1c is independently selected from H, halogen, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene)n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c may join to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0414] n is selected from 1, 2, 3, 4, 5, or 6;

[0415] L 1c and L 1d may simultaneously be a bond;

[0416] L 1e is selected from -C(O)-, -NHC(O)-, or -C(O)-NHC(O)-;

[0417] L2 is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0418] L3 is an optionally substituted or unsubstituted spacer.

[0419] In a more particular embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein:

[0420] D is a compound of formula (D’), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0421] wherein,

[0422] A1’ is selected from -O-C 0-6 alkylene-, -NH-C 0-6alkylene- or -S-C 0-6 alkylene-;

[0423] A2is selected from -(CR a R b ) k -, -(CR a R b ) k -O-(CR a R b ) k -, C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0424] k is 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6;

[0425] each variable in formula (D’) is as defined herein;

[0426] L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0427] L 1a is

[0428] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; optionally 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are replaced by a heteroatom of O, S, N, and, optionally, each -CH2- in C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is substituted with 1 or 2 R 1a ;

[0429] each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be linked to form C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0430] L 1b is optionally substituted with a hydrophilic group selected from: R 1band R 1b’ is independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0431] L 1c is selected from a chemical bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0432] L 1d is selected from a chemical bond, C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene, any 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene, each -CH2- in said C 1-10 alkylene, C 2- 10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1c ;

[0433] each R 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1c on any identical or different carbon atom can be linked to form C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0434] L 1c and L 1d may simultaneously be a chemical bond;

[0435] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0436] L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different and independently of each other selected from the group consisting of the residues of the amino acids alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0437] L3is an optionally substituted or unsubstituted spacer;

[0438] with the proviso that the linker-drug conjugate at least meets one of the following conditions:

[0439] 1) m is selected from 2, 3, 4, 5 or 6;

[0440] 2) L1— L2— L3— is not of the structure:

[0441] In a more specific embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein L1is L 1a -L 1b -L 1c -L 1d -L 1e -;

[0442] L 1a is selected from

[0443] L 1b is selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene is optionally substituted with 1 or 2 R 1a , R1a H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may join to form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0444] L 1b optionally substituted with a hydrophilic group selected from:

[0445] L 1c is selected from a bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0446] L 1d is selected from a bond, C 1-8 alkylene or -(CH2CH2O) w -C 1-4 alkylene; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH2O) n -C 1-4 alkyl or -C(O)NH-(CH2CH2O) n -C 1-4 alkyl;

[0447] w and n are independently selected from 1, 2, 3, 4, 5 or 6;

[0448] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0449] preferably,

[0450] L1is selected from

[0451] each m, w and n are independently selected from 1, 2, 3, 4, 5 or 6;

[0452] each R 1a and R 1a’ are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0453] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene or 3-5 membered heterocyclyl ene;

[0454] more preferably,

[0455] L1is selected from the group consisting of:

[0456] In a more specific embodiment, the application relates to a linker-drug conjugate of formula (LD) as described above, wherein L2is selected from the group consisting of divalent peptidic radicals comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0457] each amino acid residue in said L2is optionally substituted by 1, 2 or 3 R 2a ;

[0458] each R 2a is independently selected from the group consisting of H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0459] Preferably,

[0460] L2is selected from the group consisting of divalent peptidic radicals comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0461] each amino acid residue in said L2is optionally substituted by 1, 2 or 3 R 2a ;

[0462] each R 2a is independently selected from the group consisting of H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3or OCH3;

[0463] More preferably,

[0464] L2is selected from the group consisting of:

[0465] L2is linked to L1via the a terminus and to L3via the b terminus.

[0466] In a more specific embodiment, the application relates to a linker-drug conjugate of formula (LD) as described above, wherein L1is L 1a -L 1b -L 1c -L 1d -L1e -;

[0467] L 1a selected from

[0468] L 1b selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene is optionally substituted with 1 or 2 R 1a substituents, R 1a selected from H, halo, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0469] L 1b optionally substituted with a hydrophilic group selected from:

[0470] L 1c selected from a bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0471] L 1d selected from a bond, C 1-8 alkylene or -(CH2CH20) w -C 1-4 alkylene-; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH20) n -C 1-4 alkyl or -C(O)NH-(CH2CH20) n -C 1-4 alkyl;

[0472] w and n are independently selected from 1, 2, 3, 4, 5 or 6;

[0473] L 1e selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0474] L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0475] each amino acid residue in L2 is optionally substituted with 1, 2 or 3 R 2a ;

[0476] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0477] L3 is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-;

[0478] L3 is optionally substituted with 1, 2 or 3 R 3a ;

[0479] each R 3a is selected from H, C 1-6 alkyl or C 1-6 haloalkyl; 1-6 1-6 haloalkoxy.

[0480] In a more specific embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein L1 is selected from

[0481] each m, w and n is independently selected from 1, 2, 3, 4, 5 or 6;

[0482] each R 1a and R 1a’ are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0483] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene or 3-5 membered heterocyclylene;

[0484] Preferably,

[0485] L1 is selected from:

[0486] ​L2is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0487] each amino acid residue in L2is optionally substituted with 1, 2 or 3 R 2a ;

[0488] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3or OCH3;

[0489] Preferably,

[0490] L2is selected from:

[0491] L2is attached to L1via the a terminus and to L3via the b terminus;

[0492] L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-.

[0493] In a more specific embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein D is selected from a compound of formula (D’), formula (D-1’), formula (D-2’), formula (D-3’), or formula (D-4’), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof:

[0494] wherein,

[0495] A1’is a divalent group resulting from the attachment of A1to the linker and is selected from -O-, -OCH2-, -NH-, -NHCH2-, -S- or -SCH2-;

[0496] the other variables are as defined herein.

[0497] In a more specific embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein D has the structure of formula (D-1’), wherein R b is H, i.e. the carbon atom to which R b is attached does not have chirality, and therefore formula (D-1’) also comprises the structure of Formula (D-1a').

[0498] In a more particular embodiment, the present application relates to a linker-drug conjugate of the above Formula (LD) wherein D is derived from a monovalent radical of a compound 1-21, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof, preferably the monovalent radical of a compound 1-21 has the structure:

[0499] In a more particular embodiment, the present application relates to a linker-drug conjugate of Formula (LD-1), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0500] wherein,

[0501] each R 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0502] alternatively, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0503] m is selected from 2, 3, 4, 5 or 6;

[0504] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0505] with the proviso that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0506] D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, such as a DNA topoisomerase I inhibitor;

[0507] preferably,

[0508] each R 1a and R 1a’ is independently selected from H or C 1-6alkyl;

[0509] or, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene;

[0510] m is selected from 2, 3, 4, 5, or 6;

[0511] each R 2a is independently selected from H, halo, C 1-6 alkyl, or C 1-6 alkoxy;

[0512] with the proviso that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0513] D is a camptothecin derivative, preferably selected from a compound of formula (D) described herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or a mixture thereof;

[0514] More preferably,

[0515] each R 1a and R 1a’ is independently selected from H or C 1-4 alkyl, for example methyl;

[0516] or, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene, for example cyclopropylene;

[0517] m is selected from 2, 3, 4, 5, or 6;

[0518] each R 2a is independently selected from H, halo, C 1-6 alkyl, or C 1-6 alkoxy, for example H, F, methyl, or methoxy;

[0519] with the proviso that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0520] said D is selected from a compound of formula (D-5’), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or a mixture thereof:

[0521] k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2;

[0522] each R a and R b is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0523] * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0524] R1and R2are independently selected from H or C 1-6 alkyl;

[0525] or, R1and R2, or the carbon atom to which R2is attached, are joined to form a C 5-7 cycloalkyl, preferably a six-membered cycloalkyl;

[0526] R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl;

[0527] R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F;

[0528] R5is OH;

[0529] R6is -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl;

[0530] said D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined herein.

[0531] In a more particular embodiment, the present application relates to a linker-drug conjugate of formula (LD-2), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0532] each R 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0533] or, R 1a , R1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0534] m is selected from 1, 2, 3, 4, 5 or 6;

[0535] w and v are independently selected from 1, 2, 3 or 4;

[0536] each R 2a is independently selected from H, halo, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0537] provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0538] D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, such as a DNA topoisomerase I inhibitor;

[0539] Preferably,

[0540] each R 1a and R 1a’ is independently selected from H or C 1-6 alkyl;

[0541] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene;

[0542] m, w and v are independently selected from 1, 2, 3 or 4;

[0543] each R 2a is independently selected from H, halo, C 1-6 alkyl or C 1-6 alkoxy;

[0544] provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0545] D is a camptothecin derivative, preferably selected from a compound of formula (D) as described herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof;

[0546] More preferably,

[0547] Each R 1a and R 1a’ Independently selected from H or C 1-4 Alkyl groups, such as methyl groups;

[0548] Or, R on any carbon atom 1a R 1a’ Together with the carbon atoms they are attached to, they form C 3-5 Cycloalkylene compounds, such as cyclopropylene compounds;

[0549] m is selected from 2, 3, or 4;

[0550] w is selected from 1, 2, or 3;

[0551] v is selected from 1, 2, or 3;

[0552] Each R 2a Independently selected from H, halogens, C 1-6 Alkyl or C 1-6 Alkyl groups, such as H, F, methyl, or methoxy groups;

[0553] The premise is that all R 1a R 1a’ And 5 Rs 2a Not both H;

[0554] The D is selected from compounds of formula (D-5'), or pharmaceutically acceptable salts, isotopic variants, tautomers, stereoisomers, racemates, polymorphs, hydrates or solvates, or mixtures thereof:

[0555] k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, more preferably 2, 3 or 4, and even more preferably 2;

[0556] Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups;

[0557] * indicates a chiral center, selected from the (S) or (R) absolute configuration, or a mixture thereof;

[0558] R1 and R2 are independently selected from H or C. 1-6 alkyl;

[0559] Alternatively, R1 connects to R2 or the carbon atom bonded to R2 to form C. 5-7 Cycloalkyl groups, preferably six-membered cycloalkyl groups;

[0560] R3 is selected from C 1-6 Alkyl or C1-6 Halogenated alkyl groups, preferably C 1-6 Alkyl, more preferably C 1-4 Alkyl groups, such as methyl groups;

[0561] R4 is selected from halogen, OH, NH2, or C. 1-6 Alkyl groups, preferably halogens, more preferably F;

[0562] R5 is OH;

[0563] R6 is -C 1-4 Alkylene-C 3-5 Cycloalkyl groups, such as -CH2-cyclopropyl;

[0564] The D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is defined as defined herein.

[0565] In a more specific embodiment, the present invention relates to a linker-drug conjugate of formula (LD-3), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof:

[0566] in,

[0567] Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups;

[0568] Or, R on any carbon atom 1a R 1a’ Together with the carbon atoms they are attached to, they form C 3-7 Cycloalkylene or 3-7 membered heterocyclic alkylene;

[0569] m and n are independently selected from 1, 2, 3, 4, 5 or 6;

[0570] Each R 2a Independently selected from H, halogens, C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Halogenated alkyl or C 1-6 Halogenated alkoxy groups;

[0571] D is selected from compounds of formula (D) described herein, or pharmaceutically acceptable salts, isotopic variants, tautomers, stereoisomers, racemates, polymorphs, hydrates or solvates, or mixtures thereof;

[0572] Preferably,

[0573] Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl;

[0574] Or, R on any carbon atom 1a R 1a’ Together with the carbon atoms they are attached to, they form C 3-5 Cycloalkylene compounds, such as cyclopropylene compounds;

[0575] m is selected from 2, 3, 4, 5, or 6;

[0576] n is selected from 2, 3, or 4;

[0577] Each R 2a Independently selected from H, halogens, C 1-6 Alkyl or C 1-6 Alkyl groups, such as H, F, methyl, or methoxy groups;

[0578] D is selected from compounds of formula (D-6'), or pharmaceutically acceptable salts, isotopic variants, tautomers, stereoisomers, racemates, polymorphs, hydrates or solvates, or mixtures thereof:

[0579] k' is selected from 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, more preferably 1;

[0580] Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups;

[0581] R1 and R2 are independently selected from H or C. 1-6 alkyl;

[0582] Alternatively, R1 connects to R2 or the carbon atom bonded to R2 to form C. 5-7 Cycloalkyl groups, preferably six-membered cycloalkyl groups;

[0583] R3 is selected from C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably C 1-6 Alkyl, more preferably C 1-4 Alkyl groups, such as methyl groups;

[0584] R4 is selected from halogen, OH, NH2, or C. 1-6 Alkyl groups, preferably halogens, more preferably F;

[0585] R5 is OH;

[0586] R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl;

[0587] D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined herein.

[0588] In a more specific embodiment, the present application relates to a linker-drug conjugate of formula (LD-4), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0589] wherein,

[0590] R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0591] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0592] with the proviso that all R 1b , R 1b’ and 5 R 2a are not simultaneously H;

[0593] D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, for example a DNA topoisomerase I inhibitor;

[0594] Preferably,

[0595] R 1b and R 1b’ are independently selected from H or C 1-6 alkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene;

[0596] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy;

[0597] provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H;

[0598] D is a camptothecin derivative, preferably selected from the compounds of formula (D) described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof;

[0599] More preferably,

[0600] R 1b and R 1b’ are independently selected from H or C 1-4 alkyl, for example H or methyl; alternatively, R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene;

[0601] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy;

[0602] provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H;

[0603] D is selected from the compounds of formula (D-5’), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof:

[0604] k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2;

[0605] each R a and R b is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0606] * is a chiral center selected from the (S) or (R) absolute configuration, or mixtures thereof;

[0607] R1and R2are independently selected from H or C 1-6 alkyl;

[0608] or R1and R2or the carbon atom to which R2is attached are joined to form a C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl;

[0609] R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl;

[0610] R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F;

[0611] R5is OH;

[0612] R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl;

[0613] said D is more preferably a compound of formula (D-1') or (D-2'), wherein the various groups are as defined herein.

[0614] In a particular embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein said D has the structure of formula (D-1'), (D-1a'), (D-2'), (D-3'), (D-4'), (D-5') or (D-6') as described above, wherein when described as "*, *1, *2, *3 are chiral centers", both the case when R1, R a or R b when R1, R a or R b each independently H, in which case *, *1, *2, *3 are not chiral.

[0615] In a more particular embodiment, the present application relates to a linker-drug conjugate selected from the group consisting of the compounds of Table 1, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0616] Table 1. Representative linker-drug conjugates described herein

[0617] 1.3 Ligand drug conjugate

[0618] In one embodiment, the present application relates to a ligand drug conjugate; in a preferred embodiment, the present application relates to an antibody drug conjugate.

[0619] In one embodiment, the present application relates to a ligand drug conjugate of formula (X), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0620] T— [L1’— L2— L3— D] y (X)

[0621] wherein,

[0622] T is a targeting moiety;

[0623] D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity;

[0624] y is selected from 1 to 20;

[0625] L1’ is -L 1a ’-L 1b -L 1c -L 1d -L 1e -;

[0626] L 1a ’ is formed by reacting a thiol reactive group L 1a with the targeting moiety T, for example L 1a ’ is attached to T through the # end;

[0627] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; optionally 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are replaced by a heteroatom of O, S, N, while each -CH2- in C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1a ;

[0628] each R 1a is independently selected from H, halo, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on the same or different carbon atom can be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0629] L 1b optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0630] L 1c is selected from a bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0631] L 1d is selected from a bond, C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene, any 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced with a heteroatom of O, S, N, and each -CH2- in said C 1-10 alkylene, C 2- 10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1c ;

[0632] each R 1c is independently selected from H, halo, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c may be linked to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0633] n is selected from 1, 2, 3, 4, 5 or 6;

[0634] L 1c and L 1d may simultaneously be a chemical bond;

[0635] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0636] L2 is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0637] L3 is an optionally substituted or unsubstituted spacer.

[0638] T

[0639] In one embodiment, T is a targeting moiety.

[0640] In one embodiment, T is a small molecule ligand, such as a folate derivative, a glutamic acid urea derivative, a somatostatin derivative, an arylsulfonamide derivative (e.g. a carbonic anhydrase IX inhibitor), an ICG dye, a cyanine dye or a derivative thereof.

[0641] In one embodiment, T is an antibody or antigen binding fragment thereof, said antibody being selected from a chimeric antibody, a humanized antibody or a fully human antibody, preferably a monoclonal antibody (mAb).

[0642] In one particular embodiment, T is an anti-CD20 antibody; in another particular embodiment, T is an anti-CD22 antibody; in another particular embodiment, T is an anti-; in another particular embodiment, T is an anti-CD30 antibody; in another particular embodiment, T is an anti-CD33 antibody; in another particular embodiment, T is an anti-CD44 antibody; in another particular embodiment, T is an anti-CD56 antibody; in another particular embodiment, T is an anti-CD70 antibody; in another particular embodiment, T is an anti-CD73 antibody; in another particular embodiment, T is an anti-CD105 antibody; in another particular embodiment, T is an anti-CEA antibody; in another particular embodiment, T is an anti-A33 antibody; in another particular embodiment, T is an anti-Cripto antibody; in another particular embodiment, T is an anti-EphA2 antibody; in another particular embodiment, T is an anti-G250 antibody; in another particular embodiment, T is an anti-HER2 (ErbB2) antibody; in another particular embodiment, T is an anti-EGFR antibody; in another particular embodiment, T is an anti-B7-H3 antibody; in another particular embodiment, T is an anti-c-Met antibody; in another particular embodiment, T is an anti-HER3 (ErbB3) antibody; in another particular embodiment, T is an anti-HER4 (ErbB4) antibody; in another particular embodiment, T is an anti-MUC1 antibody; in another particular embodiment, T is an anti-Lewis Y antibody; in another particular embodiment, T is an anti-VEGFR antibody; in another particular embodiment, T is an anti-GPNMB antibody; in another particular embodiment, T is an anti-Integrin antibody; in another particular embodiment, T is an anti-PSMA antibody; in another particular embodiment, T is an anti-Tenascin-C antibody; in another particular embodiment, T is an anti-SLC44A4 antibody or an anti-Mesothelin antibody; in another particular embodiment, the aforementioned antibodies can be bispecific antibodies or multispecific antibodies.

[0643] In one specific embodiment, T is Trastuzumab; in another specific embodiment, T is Patritumab; in another specific embodiment, T is Pertuzumab; in another specific embodiment, T is Nimotuzumab; in another specific embodiment, T is Enoblituzumab; in another specific embodiment, T is Emibetuzumab; in another specific embodiment, T is Inotuzumab; in another specific embodiment, T is Pinatuzumab; in another specific embodiment, T is Brentuximab; in another specific embodiment, T is Gemtuzumab; in another specific embodiment, T is Bivatuzumab; in another specific embodiment, T is Lorvotuzumab; in another specific embodiment, T is cBR96; in another specific embodiment, T is Glematumamab; in another specific embodiment, T is Glembatumumab.

[0644] L1’

[0645] In one embodiment, L1’ is -L 1a ’-L 1b -L 1c -L 1d -L 1e -.

[0646] In one specific embodiment, L1’ is: wherein each variable is as defined herein. In one specific embodiment, L1’ is: L1’ is connected to T via the # end.

[0647] L

[0648] In one embodiment, L 1a ’ is formed by reacting a thiol reactive group L 1a with a targeting moiety T.

[0649] In one embodiment, L 1a ’ is In another embodiment, L 1a ’ is In another embodiment, L 1a ’ is L 1a ’ is connected to T via the # end.

[0650] L 1b , L 1c , L 1d , L 1e , L2, L3 and D

[0651] L 1b , L 1c , L 1d , L 1e , L2, L3 and D are as defined herein.

[0652] y

[0653] In one embodiment, y is an integer or decimal number selected from 0 to 20; in another embodiment, y is an integer or decimal number selected from 0 to 10; in another embodiment, y is an integer or decimal number selected from 4 to 10.

[0654] In one particular embodiment, y is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15; in another particular embodiment, y is 5.5, 6.5, 7.5, 8.5, 9.5; in another particular embodiment, y is 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9 or 9.0.

[0655] Any of the technical solutions in any of the above particular embodiments or any combination thereof can be combined with any of the technical solutions in other particular embodiments or any combination thereof. For example, any of the technical solutions of T or any combination thereof can be combined with any of the technical solutions of y, L1, L2, L3, L 1a , L 1b , L 1c , L 1d , L 1e , D, etc. or any combination thereof. The present application is intended to include all combinations of these technical solutions, which are not listed one by one due to the length.

[0656] In a more particular embodiment, the present application relates to the ligand drug conjugate of formula (X) above, wherein T is a small molecule ligand, such as a folic acid derivative, a glutamic acid urea derivative, a somatostatin derivative, an arylsulfonamide derivative (e.g. a carbonic anhydrase IX inhibitor), an ICG dye, a cyanine dye or a derivative thereof;

[0657] The preferred ligand is selected from an antibody or an antigen binding fragment thereof, said antibody being selected from a chimeric antibody, a humanized antibody or a fully human antibody; preferably a monoclonal antibody (mAb);

[0658] Preferably, the antibody or antigen-binding fragment thereof is selected from at least one antibody or antigen-binding fragment thereof of an anti-CD20 antibody, an anti-CD22 antibody, an anti-CD30 antibody, an anti-CD33 antibody, an anti-CD44 antibody, an anti-CD56 antibody, an anti-CD70 antibody, an anti-CD73 antibody, an anti-CD105 antibody, an anti-CEA antibody, an anti-A33 antibody, an anti-Cripto antibody, an anti-EphA2 antibody, an anti-G250 antibody, an anti-HER2 (ErbB2) antibody, an anti-EGFR antibody, an anti-B7-H3 antibody, an anti-c-Met antibody, an anti-HER3 (ErbB3) antibody, an anti-HER4 (ErbB4) antibody, an anti-MUC1 antibody, an anti-Lewis Y antibody, an anti-VEGFR antibody, an anti-GPNMB antibody, an anti-Integrin antibody, an anti-PSMA antibody, an anti-Tenascin-C antibody, an anti-SLC44A4 antibody, or an anti-Mesothelin antibody, which can be a bispecific antibody or a multispecific antibody;

[0659] Preferably, the antibody or antigen-binding fragment thereof is selected from at least one antibody or antigen-binding fragment thereof of Trastuzumab, Pertuzumab, Nimotuzumab, Enoblituzumab, Emibetuzumab, Inotuzumab, Pinatuzumab, Brentuximab, Gemtuzumab, Bivatuzumab, Lorvotuzumab, cBR96, and Glematumamab or Glembatumumab.

[0660] More preferably, T is Trastuzumab, Patritumab, Pertuzumab, or Nimotuzumab, more preferably Trastuzumab.

[0661] In a more specific embodiment, the present application relates to a Ligand Drug Conjugate of the above formula (X), wherein D is derived from a monovalent group of a compound of formula (D) as described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof.

[0662] In a more specific embodiment, the present application relates to a Ligand Drug Conjugate of the above formula (X), wherein D is a compound of formula (D’), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof:

[0663] wherein,

[0664] A1' is selected from -O-C 0-6 alkylene-, -NH-C 0-6 alkylene-, or -S-C 0-6 alkylene-;

[0665] The other variables are as defined herein.

[0666] In a more particular embodiment, the application relates to a Ligand Drug Conjugate of formula (X) as described above, wherein L1' is -L 1a '-L 1b -L 1c -L 1d -L 1e -;

[0667] L 1a ' is selected from L 1a ' is attached to T via the # end;

[0668] L 1b is selected from C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene; each -CH2- in said C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1a ;

[0669] each R 1a is independently selected from halogen, C 1-6 alkyl, or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be connected to form a C 3-10 cycloalkylene, or 3-10 membered heterocyclylene;

[0670] L 1b is optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ , and the carbon atom to which they are attached, together form a C 3-7 cycloalkylene, or 3-7 membered heterocyclylene;

[0671] L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-;

[0672] L 1d is selected from a chemical bond, C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, said C1-10 alkylene, C 2-10 alkenylene or C 2-10 any 1, 2 or 3 non-adjacent carbon atoms in the alkynylene group are optionally replaced by a heteroatom of O, S, N, while, C 1-10 alkylene, C 2- 10 alkenylene or C 2-10 each -CH2- in the alkynylene group is optionally substituted by 1 or 2 R 1c ;

[0673] each R 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl;

[0674] L 1c and L 1d may simultaneously be a chemical bond;

[0675] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0676] L2 is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (Ile), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valinol (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine, preferably L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine;

[0677] each amino acid residue in said L2 is optionally substituted by 1, 2 or 3 R 2a ;

[0678] each R 2a is independently selected from halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C1-6 haloalkoxy;

[0679] L3 is an optionally substituted or unsubstituted spacer,

[0680] provided that the Ligand Drug Conjugate meets at least one of the following conditions:

[0681] 1) L 1b is substituted with 1 or 2 R 1a ;

[0682] each R 1a is independently selected from the group consisting of halogen, C 1-6 alkyl, or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0683] 2) L 1b is substituted with a hydrophilic group selected from the group consisting of: R 1b , R 1b’ , and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene;

[0684] 3) at least one amino acid residue in L2 is substituted with 1, 2, or 3 R 2a ;

[0685] each R 2a is independently selected from the group consisting of halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, or C 1-6 haloalkoxy;

[0686] Preferably,

[0687] L1’ is -L 1a ’-L 1b -L 1c -L 1d -L 1e -;

[0688] L 1a ’ is selected from L 1a ’ is connected to T via the # end;

[0689] L 1b is C 1-8 alkylene; at least one -CH2- in said C 1-8 alkylene is substituted with 1 or 2 R1a substituted;

[0690] each R 1a is independently selected from halogen or C 1-6 alkyl; or, two R 1a on the same or different carbon atoms can be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkylene;

[0691] L 1b optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl;

[0692] L 1c is selected from a bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0693] L 1d is selected from a bond or C 1-8 alkylene, any 1, 2 or 3 non-adjacent carbon atoms in said C 1-8 alkylene are optionally replaced with a heteroatom of O, S, N, while each -CH2- in said C 1-8 alkylene is optionally substituted with 1 or 2 R 1c ;

[0694] each R 1c is independently selected from H, halogen or C 1-6 alkyl;

[0695] L 1c and L 1d may both be a bond, L 1c and L 1d are preferably a bond;

[0696] L 1e is selected from -C(O)- or -NHC(O)-, preferably -C(O)-;

[0697] L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine;

[0698] each amino acid residue in said L2 is optionally substituted with 1, 2 or 3 R 2a ;

[0699] each R 2a is independently selected from halogen, C 1-6alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0700] L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-;

[0701] said L3is optionally substituted with 1, 2, or 3 R 3a ;

[0702] said R 3a is selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0703] with the proviso that the Ligand Drug Conjugate at least meets one of the following conditions:

[0704] 1) L 1b is substituted with 1 or 2 R 1a ;

[0705] each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be connected to form C 3-10 cycloalkylene or 3-10 membered heterocyclyl ene;

[0706] 2) L 1b is substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0707] 3) at least one amino acid residue in said L2is substituted with 1, 2, or 3 R 2a ;

[0708] each R 2a is independently selected from halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy.

[0709] In a more specific embodiment, the present application relates to Ligand Drug Conjugates of Formula (X) as described above, wherein D is derived from a monovalent radical of a compound of Formula (D) as described herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or mixtures thereof, for example, selected from a compound of Formula (D’):

[0710] L1’is -L 1a L1’is -L 1b L1’is -L 1c L1’is -L 1d L1’is -L 1e L1’is -L

[0711] L1’is -L 1a L1’is -L L1’is -L 1a L1’is -L

[0712] L1’is -L 1b L1’is -L 1-10 L1’is -L 2-10 L1’is -L 2-10 L1’is -L 1-10 L1’is -L 2-10 L1’is -L 2-10 L1’is -L 1-10 L1’is -L 2-10 L1’is -L 2-10 L1’is -L 1a L1’is -L

[0713] L1’is -L 1a L1’is -L 1-6 L1’is -L 1-6 L1’is -L 1a L1’is -L 3-10 L1’is -L

[0714] L1’is -L 1c L1’is -L

[0715] L1’is -L 1d L1’is -L 1-10 L1’is -L 2-10 L1’is -L 2-10 L1’is -L 1-10 L1’is -L 2-10 L1’is -L 2-10 L1’is -LAny 1, 2, or 3 non-adjacent carbon atoms in the alkylene group are optionally replaced with a heteroatom of O, S, or N, while C 1-10 alkylene, C 2- 10 alkylene, C 2-10 each -CH2- in the alkylene group is optionally replaced with 1 or 2 R 1c substituents;

[0716] each R 1c is independently selected from H, halo, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c on any identical or different carbon atom can be joined to form a C 3-10 cycloalkylene, or 3-10 membered heterocyclyl ene;

[0717] n is selected from 1, 2, 3, 4, 5, or 6;

[0718] L 1c and L 1d may both be a bond at the same time;

[0719] L 1e is selected from -C(O)-, -NHC(O)-, or -C(O)-NHC(O)-;

[0720] L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different and independently of each other selected from the group consisting of the residues of the amino acids alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (Ile), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0721] L3is an optionally substituted or unsubstituted spacer.

[0722] In a more particular embodiment, the present application relates to a Ligand Drug Conjugate of formula (X) as described above, wherein:

[0723] D is a compound of formula (D’), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0724] wherein,

[0725] A2is selected from -(CR a R b ) k -, -(CR a R b ) k -O-(CR a R b ) k -, C 3-7 cycloalkyl or 3-7 membered heterocyclyl;

[0726] k is 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6;

[0727] each of the other variables in formula (D’) is as defined herein;

[0728] L1’is -L 1a ’-L 1b -L 1c -L 1d -L 1e -;

[0729] L1a Selected from L 1a 'Connect to T via the # terminal;

[0730] L 1b Selected from C 1-10 Alkylene, C 2-10 imide or C 2-10 Isomerynethiol; the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2-10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1a replace;

[0731] Each R 1a Independently selected from H, halogen, C 1-6 Alkyl or C 1-6 Haloalkyl; or, two R atoms on any same or different carbon atoms. 1a Can be connected to form C 3-10 Cycloalkylene or 3-10 membered heterocyclic cycloalkylene groups;

[0732] L 1b Optionally replaced by a hydrophilic group, said hydrophilic group being selected from: R 1b and R 1b’ Independently selected from H and C 1-6 Alkyl or C 1-6 Haloalkyl; or, R 1b R 1b’ Together with the carbon atoms they are attached to, they form C 3-7 Cycloalkylene or 3-7 membered heterocyclic alkylene;

[0733] L 1c Selected from chemical bonds, -C(O)-, -C(O)NH-, or -NHC(O)-;

[0734] L 1d Selected from chemical bonds, C 1-10 Alkylene, C 2-10 imide or C 2-10 Imyynyl group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2-10 alkylene or C 2-10 each -CH2- in the alkynylene group is optionally substituted with 1 or 2 R 1c substituted;

[0735] each R 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1c may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene;

[0736] L 1c and L 1d may simultaneously be a chemical bond;

[0737] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0738] L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or non-natural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valinol (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine;

[0739] L3is an optionally substituted or unsubstituted spacer;

[0740] with the proviso that the linker-drug conjugate at least meets one of the following conditions:

[0741] 1) m is selected from 2, 3, 4, 5 or 6;

[0742] 2) L1’— L2— L3— is not the following structure:

[0743] In a more specific embodiment, the present application relates to the ligand drug conjugate of formula (X) above, wherein:

[0744] L1' is L 1a L1' is L 1b L1' is L 1c L1' is L 1d L1' is L 1e L1' is L

[0745] L1' is L 1a L1' is L L1' is L L1' is L

[0746] L1' is L 1b L1' is L 1-8 L1' is L w L1' is L 1-4 L1' is L 2-8 L1' is L 2-8 L1' is L 1-8 L1' is L w L1' is L 1-4 L1' is L 2-8 L1' is L 2-8 L1' is L 1a L1' is L 1a L1' is L 1-6 L1' is L 1-6 L1' is L 1a L1' is L 3-7 L1' is L

[0747] L1' is L 1b L1' is L

[0748] L1' is L 1c L1' is L

[0749] L1' is L 1d L1' is L 1-8 L1' is L w L1' is L 1-4 L1' is L 1-8 L1' is L n L1' is L 1-4 L1' is L n L1' is L 1-4 L1' is L

[0750] L1' is L

[0751] L1' is L 1eselected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0752] Preferably,

[0753] L1' is selected from L1' is attached to T via the # end;

[0754] each m, w and n is independently selected from 1, 2, 3, 4, 5 or 6;

[0755] each R 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0756] or, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene or 3-5 membered heterocyclyl ene;

[0757] More preferably,

[0758] L1' is selected from: L1' is attached to T via the # end.

[0759] In a more particular embodiment, the application relates to a Ligand Drug Conjugate of formula (X) as described above, wherein:

[0760] L2 is selected from a divalent peptidyl group consisting of 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0761] each amino acid residue in said L2 is optionally substituted with 1, 2 or 3 R 2a ;

[0762] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0763] Preferably,

[0764] L2 is selected from a bivalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0765] each amino acid residue in L2 is optionally substituted with 1, 2 or 3 R 2a ;

[0766] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, such as H, F, CH3 or OCH3;

[0767] More preferably, L2 is selected from:

[0768] L2 is selected from:

[0769] L2 is connected to L1 via the a terminus and to L3 via the b terminus.

[0770] In a more specific embodiment, the application relates to a Ligand Drug Conjugate of formula (X) as described above, wherein:

[0771] L1' is L 1a ' - L 1b - L 1c - L 1d - L 1e ;

[0772] L 1a ' is selected from connected to T via the a terminus;

[0773] L 1b is selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene is optionally substituted with 1 or 2 R 1a , R 1a is selected from H, halogen, C 1-6 alkyl or C 1-6haloalkyl; or, two R 1a may be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0774] L 1b optionally substituted with a hydrophilic group selected from:

[0775] L 1c is selected from a chemical bond, -C(O)-, -C(O)NH- or -NHC(O)-;

[0776] L 1d is selected from a chemical bond, C 1-8 alkylene or -(CH2CH2O) w -C 1-4 alkylene-; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH2O) n -C 1-4 alkyl or -C(O)NH-(CH2CH2O) n -C 1-4 alkyl;

[0777] w and n are independently selected from 1, 2, 3, 4, 5 or 6;

[0778] L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-;

[0779] L2 is selected from a divalent peptidyl group consisting of 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0780] each amino acid residue in said L2 is optionally substituted with 1, 2 or 3 R 2a ;

[0781] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0782] L3 is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-.

[0783] In a more specific embodiment, the application relates to Ligand Drug Conjugates of formula (X) as described above, wherein:

[0784] L1’ is selected from

[0785] each m, w and n is independently selected from 1, 2, 3, 4, 5 or 6;

[0786] each R 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0787] or, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene or 3-5 membered heterocyclylene;

[0788] Preferably,

[0789] L1’ is selected from: L1’ is connected to T via the a end;

[0790] L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-;

[0791] each amino acid residue in said L2 is optionally substituted with 1, 2 or 3 R 2a ;

[0792] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3 or OCH3;

[0793] Preferably,

[0794] L2 is selected from:

[0795] L2 is connected to L1 via the a end and to L3 via the b end;

[0796] L3 is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-.

[0797] In a more specific embodiment, the present invention relates to ligand drug conjugates of formula (X) above, wherein D is selected from compounds of formula (D'), (D-1'), (D-2'), (D-3') or (D-4'), or pharmaceutically acceptable salts, isotopic variants, tautomers, stereoisomers, racemates, polymorphs, hydrates or solvates, or mixtures thereof:

[0798] in,

[0799] A1' is a divalent group formed by A1 and a linker, selected from -O-, -OCH2-, -NH-, -NHCH2-, -S-, or -S-CH2-;

[0800] Other variables are as defined in this paper;

[0801] Preferably, D is selected from:

[0802] In a more specific embodiment, the present invention relates to a ligand drug conjugate of formula (X) above, wherein D has the structure of formula (D-1') above, wherein R b For H, i.e. R b The attached carbon atom is not chiral, therefore equation (D-1) also contains The structure shown in equation (D-1a').

[0803] In a more specific embodiment, the present invention relates to ligand drug conjugates of formula (X-1a), (X-1b) or (X-1c), or pharmaceutically acceptable salts, isotopic variants, tautomers, stereoisomers, racemates, polymorphs, hydrates or solvates, or mixtures thereof:

[0804] in,

[0805] mAb is a monoclonal antibody;

[0806] y is selected from 1 to 20, preferably from 1 to 10;

[0807] Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups;

[0808] Or, R on any carbon atom 1a R 1a’ Together with the carbon atoms they are attached to, they form C 3-7 Cycloalkylene or 3-7 membered heterocyclic alkylene;

[0809] m is selected from 1, 2, 3, 4, 5 or 6;

[0810] each R 2a is independently selected from H, halo, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0811] provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0812] D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, such as a DNA topoisomerase I inhibitor;

[0813] Preferably,

[0814] mAb is a monoclonal antibody;

[0815] y is selected from an integer or a decimal number from 1 to 10;

[0816] each R 1a and R 1a’ is independently selected from H or C 1-6 alkyl;

[0817] Alternatively, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene;

[0818] m is selected from 1, 2, 3, 4, 5 or 6;

[0819] each R 2a is independently selected from H, halo, C 1-6 alkyl or C 1-6 alkoxy;

[0820] provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0821] D is a camptothecin derivative, preferably selected from a compound of formula (D) herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof;

[0822] More preferably,

[0823] the mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab;

[0824] y is selected from an integer or a decimal number from 4 to 10;

[0825] each R 1a and R 1a’ is independently selected from H or C 1-4 alkyl, for example methyl;

[0826] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene;

[0827] m is selected from 2, 3, 4, 5 or 6;

[0828] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy;

[0829] with the proviso that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0830] D is selected from a compound of formula (D-5’), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0831] k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2;

[0832] each R a and R b is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0833] * is a chiral center selected from the (S) or (R) absolute configuration, or mixtures thereof;

[0834] R1and R2are independently selected from H or C 1-6 alkyl;

[0835] or, R1is linked to R2or the carbon atom to which R2is attached to form C 5-7cycloalkyl, preferably forming a six-membered cycloalkyl group;

[0836] R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl;

[0837] R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F;

[0838] R5is OH;

[0839] R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl;

[0840] said D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is defined as herein.

[0841] In a more specific embodiment, the present application relates to a Ligand Drug Conjugate of formula (X-2a), (X-2b) or (X-2c), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0842] mAb is a monoclonal antibody;

[0843] y is selected from 1 to 20, preferably 1 to 10;

[0844] each R 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0845] or, R 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0846] m is selected from 1, 2, 3, 4, 5 or 6;

[0847] w and v are independently selected from 1, 2, 3 or 4;

[0848] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6haloalkyl or C 1-6 haloalkoxy;

[0849] provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0850] D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, such as a DNA topoisomerase I inhibitor;

[0851] Preferably,

[0852] mAb is a monoclonal antibody;

[0853] y is selected from an integer or decimal number from 1 to 10;

[0854] each R 1a and R 1a’ is independently selected from H or C 1-6 alkyl;

[0855] Alternatively, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene;

[0856] m, w and v are independently selected from 1, 2, 3 or 4;

[0857] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy;

[0858] provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0859] D is a camptothecin derivative, preferably selected from a compound of formula (D) as described herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof;

[0860] More preferably,

[0861] mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab;

[0862] y is selected from an integer or decimal number from 4 to 10;

[0863] each R 1a and R1a’ independently selected from H or C 1-4 alkyl, for example methyl;

[0864] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene;

[0865] m is selected from 2, 3 or 4;

[0866] w is selected from 1, 2 or 3;

[0867] v is selected from 1, 2 or 3;

[0868] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy;

[0869] with the proviso that all R 1a , R 1a’ and 5 R 2a are not simultaneously H;

[0870] said D is selected from a compound of formula (D-5’), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0871] k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2;

[0872] each R a and R b is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0873] * is a chiral center selected from the (S) or (R) absolute configuration, or mixtures thereof;

[0874] R1and R2are independently selected from H or C 1-6 alkyl;

[0875] or, R1and R2or the carbon atom to which R2is attached are connected to form C 5-7 cycloalkyl, preferably a six-membered cycloalkyl;

[0876] R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C1-6 alkyl, more preferably C 1-4 alkyl, for example methyl;

[0877] R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F;

[0878] R5is OH;

[0879] R6is -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl;

[0880] said D is more preferably a compound of formula (D-1') or (D-2'), wherein the groups are as defined herein.

[0881] In a more particular embodiment, the present application relates to a Ligand Drug Conjugate of formula (X-3), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0882] wherein,

[0883] mAb is a monoclonal antibody;

[0884] y is selected from 2 to 20, preferably 3-10;

[0885] each R 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl;

[0886] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene;

[0887] m and n are independently selected from 1, 2, 3, 4, 5 or 6;

[0888] each R 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy;

[0889] D is derived from a monovalent radical of a compound of formula (D) described herein, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof;

[0890] Preferably,

[0891] mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab;

[0892] y is selected from an integer or a decimal number from 4 to 10;

[0893] each R 1a and R 1a’ is independently selected from H or C 1-6 alkyl;

[0894] or, R 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene;

[0895] m is selected from 2, 3, 4, 5 or 6;

[0896] n is selected from 2, 3 or 4;

[0897] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0898] D is selected from a compound of formula (D-6’), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0899] k’ is selected from 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, more preferably 1 ;

[0900] each R a and R b is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0901] R1and R2are independently selected from H or C 1-6 alkyl;

[0902] or, R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably a six-membered cycloalkyl;

[0903] R3is selected from C 1-6 alkyl or C1-6 Halogenated alkyl groups, preferably C 1-6 Alkyl, more preferably C 1-4 Alkyl groups, such as methyl groups;

[0904] R4 is selected from halogen, OH, NH2, or C. 1-6 Alkyl groups, preferably halogens, more preferably F;

[0905] R5 is OH;

[0906] R6 is selected from -C 1-4 Alkylene-C 3-5 Cycloalkyl groups, such as -CH2-cyclopropyl;

[0907] The D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is defined as defined herein.

[0908] In a more specific embodiment, the present invention relates to ligand drug conjugates of formula (X-4a), (X-4b) or (X-4c), or pharmaceutically acceptable salts, isotopic variants, tautomers, stereoisomers, racemates, polymorphs, hydrates or solvates, or mixtures thereof:

[0909] in,

[0910] mAb is a monoclonal antibody;

[0911] y is selected from 2 to 20, preferably 3-10;

[0912] R 1b and R 1b’ Independently selected from H and C 1-6 Alkyl or C 1-6 Haloalkyl; or, R 1b R 1b’ Together with the carbon atoms they are attached to, they form C 3-7 Cycloalkylene or 3-7 membered heterocyclic alkylene;

[0913] Each R 2a Independently selected from H, halogen, C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Halogenated alkyl or C 1-6 Halogenated alkoxy groups;

[0914] The premise is that all R 1b R 1b’ And 5 Rs 2a Not both H;

[0915] D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity, such as a DNA topoisomerase I inhibitor;

[0916] Preferably,

[0917] mAb is a monoclonal antibody;

[0918] y is selected from an integer or a decimal number from 4 to 10;

[0919] R 1b and R 1b’ are independently selected from H or C 1-6 alkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene group;

[0920] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy;

[0921] with the proviso that all R 1b , R 1b’ and 5 R 2a are not simultaneously H;

[0922] D is a camptothecin derivative, preferably derived from a compound of formula (D) as described herein, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof;

[0923] More preferably,

[0924] mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab;

[0925] y is selected from an integer or a decimal number from 4 to 10;

[0926] R 1b and R 1b’ are independently selected from H or C 1-4 alkyl, such as H or methyl; or, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene group, such as cyclopropylene;

[0927] each R 2a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, such as H, F, methyl or methoxy;

[0928] provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H;

[0929] D is selected from a compound of formula (D-5’), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof:

[0930] k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2;

[0931] each R a and R b is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-4 alkyl, for example H or methyl;

[0932] * is a chiral center selected from the (S) or (R) absolute configuration, or mixtures thereof;

[0933] R1and R2are independently selected from H or C 1-6 alkyl;

[0934] or R1and R2, or the carbon atom to which R2is attached, are connected to form a C 5-7 cycloalkyl group, preferably a six-membered cycloalkyl group;

[0935] R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl;

[0936] R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F;

[0937] R5is OH;

[0938] R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl;

[0939] More preferably, said D is a compound of formula (D-1’) or (D-2’), wherein the group definitions are as defined herein.

[0940] In a particular embodiment, the present application relates to a linker-drug conjugate of formula (LD) as described above, wherein D has the structure of formula (D-1'), (D-1a'), (D-2'), (D-3'), (D-4'), (D-5'), or (D-6') as described above, wherein when described as "*, *1, *2, *3 are chiral centers", both the case when R1, R a or R b are not H, *, *1, *2, *3 are chiral centers independently selected from (S) or (R) absolute configuration, or mixtures thereof; and also the case when R1, R a or R b are each independently H, in which case *, *1, *2, *3 are not chiral centers.

[0941] In a more particular embodiment, the present application relates to a Ligand Drug Conjugate selected from the group consisting of the compounds of Table 2-1, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof;

[0942] Preferably, the Ligand Drug Conjugate is selected from the group consisting of the compounds of Table 2-2, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof:

[0943] Table 2-1. Representative Ligand Drug Conjugate general formulae described herein

[0944] Wherein, mAb is a monoclonal antibody, preferably Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab;

[0945] y is selected from an integer or decimal number from 0 to 20, preferably from an integer or decimal number from 0 to 10; more preferably, y is selected from an integer or decimal number from 4 to 10.

[0946] Preferably, the -LD structure in the ADC is linked to a cysteine ​​residue in the mAb.

[0947] Table 2-2. Representative ligand-drug conjugates described in this article

[0948] wherein y in ADC-31, ADC-34 and ADC-77 is selected from an integer or decimal number from 0 to 20, preferably from an integer or decimal number from 0 to 10; more preferably, y is selected from an integer or decimal number from 4 to 10;

[0949] Preferably, the -L-D structure in the ADC is linked to a cysteine in an antibody, such as Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab.

[0950] II. Examples

[0951] The structure of the compounds is determined by nuclear magnetic resonance (NMR) or mass spectrometry (MS). The chemical shift δ is given in 10 -6 (ppm) units. The NMR is measured with a Bruker NMR spectrometer, the measuring solvent is deuterated dimethyl sulfoxide (DMSO-d6), deuterated chloroform (CDCl3), deuterated methanol (CD3OD), and the internal standard is tetramethylsilane (TMS).

[0952] LCMS is measured with: Agilent 1260 Infinity II (ESI) mass spectrometer, Waters UPLC H Class plus (ESI) or Shimadzu LCMS-2020 (ESI).

[0953] High performance liquid chromatography (HPLC) analysis uses Agilent 1260 or Shimadzu LC-20AD.

[0954] Preparative high performance liquid chromatography (pre-HPLC) uses GILSON GX-281 or Agilent 1260 Infinity II preparative liquid.

[0955] Chiral preparation uses supercritical fluid chromatography (SFC), and the instrument uses Shimadzu LC-30Adsf or Shimadzu LC-20AD.

[0956] Thin layer chromatography silica gel plate uses Anhui Liangchen Silicon Source Material Co., Ltd. GF254 acrylic adhesive silica gel plate. The silica gel plate used in thin layer chromatography (TLC) adopts a specification of 0.2 mm silica gel plate, and the thin layer chromatography separation and purification product adopts a specification of 0.5 mm silica gel plate.

[0957] Column chromatography generally uses 200-300 mesh silica gel from Anhui Liangchen Silicon Source Material Co., Ltd. as the carrier.

[0958] Kinase average inhibition rate and IC 50 The determination of the value was performed using a SpectraMax i3X microplate reader (Molecular Devices, USA).

[0959] The known starting materials of the present disclosure can be synthesized using or according to methods known in the art, or purchased from companies such as Bide Pharmatech, Leyan, Shaoyuan Chemical Technology, and An'egeli Chemicals.

[0960] Unless otherwise specified, the reactions in the following examples were carried out under an argon or nitrogen atmosphere.

[0961] An argon or nitrogen atmosphere refers to a reaction flask connected to an argon or nitrogen balloon with a volume of about 1 L.

[0962] A hydrogen atmosphere refers to a reaction flask connected to a hydrogen balloon with a volume of about 1 L.

[0963] The hydrogenation reaction was usually performed by repeatedly operating 3 times of vacuuming and filling with hydrogen.

[0964] An oxygen atmosphere refers to a reaction flask connected to an oxygen balloon with a volume of about 1 L.

[0965] Unless otherwise specified, the solution in the following examples refers to an aqueous solution, and the reaction temperature is room temperature, which is 20-30°C.

[0966] The monitoring of the reaction progress in the examples used thin layer chromatography (TLC), and the developing agent used in the reaction, the eluent system used in column chromatography for purifying compounds, and the developing agent system of thin layer chromatography included: A: dichloromethane / methanol system, B: petroleum ether / ethyl acetate system, the volume ratio of the solvents was adjusted according to the polarity of the compounds, and a small amount of triethylamine and acetic acid or other basic or acidic reagents could also be added for adjustment.

[0967] Example 2-1: Preparation of compound 1

[0968] (1R,3S)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1-yl)-3-hydroxycyclobutane-1-carboxamide 1

[0969] First step

[0970] Dissolve 1a (1.01 g, 3.31 mmol, prepared by the method disclosed in patent application “WO2019238046A1” page 28, example 30) in 15 mL of acetonitrile, add bromomethylcyclopropane (894.93 mg, 6.63 mmol) and potassium carbonate (916.16 mg, 6.63 mmol), stir at 80 °C for 13 hours. Add 10 mL of water, dilute the reaction solution with ethyl acetate (15 mL x 2), wash the organic phase with saturated sodium chloride solution (10 mL x 2), then dry over anhydrous sodium sulfate, filter, concentrate the filtrate by distillation under reduced pressure, and purify the obtained residue by silica gel column chromatography (mobile phase: A-petroleum ether, B-ethyl acetate; gradient elution: B%: 10%-50%), to obtain the title product 1b (1.12 g, yield: 92%) in the form of a yellow solid.

[0971] MS m / z (ESI): 359.1 [M+1].

[0972] Second step

[0973] Dissolve 1b (1.12 g, 3.05 mmol) in a mixture solvent of 5 mL of water, 5 mL of acetonitrile and 5 mL of formic acid, protect under nitrogen, add Raney nickel (261.72 mg), replace with hydrogen three times, and stir the reaction solution under hydrogen (15 Psi) at 60 °C for 4 hours. Filter the reaction solution with diatomite, wash the filter cake with dichloromethane (50 mL x 3), wash the filtrate with hydrochloric acid aqueous solution (4M, 20 mL) and then with sodium carbonate aqueous solution (12M, 50 mL), dry the organic phase over anhydrous sodium sulfate, filter, concentrate the filtrate by distillation under reduced pressure, and purify the obtained residue by reverse phase liquid chromatography (separation conditions: column: 120g Flash Coulmn Welch Ultimate XB_C18 20-40μm; mobile phase: A-water: B-acetonitrile, gradient elution, flow rate: 85 mL / min, instrument: ISCO), to obtain the title product 1c (680 mg, yield: 60%) in the form of a yellow solid.

[0974] MS m / z (ESI): 362.1 [M+1].

[0975] Third step

[0976] Dissolve 1c (680 mg, 1.85 mmol) in 10 mL of dichloromethane, protect under nitrogen, and cool to 0 °C in an ice water bath. Add sodium borohydride (108.02 mg, 2.86 mmol) in portions. Stir the reaction at 0 °C for 30 min. Add acetic acid (133.15 mg, 2.22 mmol) dropwise at 25 °C. Gas is generated. Continue stirring for 2 h. Add 30 mL of water dropwise at 15 °C. Gas is generated. Stir at 15 °C for 1.5 h. Wash the reaction with water (50 mL). Add p-toluenesulfonic acid monohydrate (35.15 mg, 184.78 µmol) to the washed organic phase at 15 °C. Stir at 15 °C for 12 h. Add 50 mL of water. Extract the reaction with dichloromethane (45 mL x 3). Dry the organic phase over anhydrous sodium sulfate. Filter and concentrate the filtrate by distillation under reduced pressure. Purify the residue obtained by silica gel column chromatography (mobile phase: A-petroleum ether, B-ethyl acetate; gradient elution: B%: 10%-50%). The title product 1d (200 mg, yield: 32%) is obtained as a yellow oil.

[0977] MS m / z (ESI): 318.1 [M+1].

[0978] Fourth step

[0979] Dissolve 1d (202.13 mg, 598.74 µmol) in 0.5 mL of methanol. Cool to 0 °C in an ice water bath. Add potassium carbonate (82.75 mg, 598.74 µmol) in portions. Stir at 0 °C for 5 h under oxygen bubbling (15 psi). Pour the reaction into 10 mL of saturated aqueous ammonium chloride solution. Concentrate by distillation under reduced pressure to remove methanol. Extract the reaction with dichloromethane (20 mL x 3). Dry the organic phase over anhydrous sodium sulfate. Filter and concentrate the filtrate by distillation under reduced pressure. The crude title product 1e (140 mg) is obtained as a yellow oil. The product is used directly in the next step without purification.

[0980] MS m / z (ESI): 334.1 [M+1].

[0981] Fifth step

[0982] Separate 1e (1.30 g, 3.88 mmol) by SFC (separation conditions: column: DAICEL CHIRALPAK AS 250 mm x 50 mm, 10 µm; mobile phase: A-carbon dioxide: B-methanol (0.1% NH3·H2O), isocratic elution: B: 20%, flow rate: 120 mL / min, instrument: Shimadzu LC-30AD sf). The title product 1e-1 (301 mg, yield: 22.1%) is obtained as a yellow solid. The title product 1e-2 (285 mg, yield: 19.4%) is obtained as a yellow solid.

[0983] Single configuration compound 1e-1

[0984] SFC analysis: Retention time 1.392 min. (Chromatography column: Chiralpak AS-3 50 x 4.6 mm I.D., 3 pm, Mobile phase: A-Carbon dioxide, B-Methanol (0.05% diethylamine), Gradient elution: B%: 5%-40%, Flow rate: 3 mL / min, Instrument: Shimadzu LC-30ADsf).

[0985] MS m / z (ESI): 334.0 [M+1].

[0986] Single configuration compound 1e-2

[0987] SFC analysis: Retention time 1.762 min. (Chromatography column: Chiralpak AS-3 50 x 4.6 mm I.D., 3 pm, Mobile phase: A-Carbon dioxide, B-Methanol (0.05% diethylamine), Gradient elution: B%: 5%-40%, Flow rate: 3 mL / min, Instrument: Shimadzu LC-30ADsf).

[0988] MS m / z (ESI): 333.9 [M+1].

[0989] Step six

[0990] Dissolve 1e-1 (301 mg, 857 pmol) in 2 mL of a mixed solution of trifluoroacetic acid and 0.5 mL of water, stir at 25 °C for 4 hours. Concentrate the reaction solution under reduced pressure, and the obtained residue gives the crude title product 1f-1 (209 mg) as a yellow solid without purification. The product is directly used in the next step reaction without purification.

[0991] MS m / z (ESI): 290.1 [M+1].

[0992] Step seven

[0993] Dissolve 1f-1 (50.0 mg, 159 pmol) and 1g (48.0 mg, 192 pmol), 4-methylbenzenesulfonic acid pyridine (8.0 mg, 31.8 pmol) in 2 mL of toluene, protect under nitrogen, stir at 120 °C for 16 hours. Filter the reaction solution with diatomite, add 20 mL of water to the filtrate, extract with dichloromethane (15 mL x 3), dry the organic phase with anhydrous sodium sulfate, filter, and concentrate the filtrate under reduced pressure. Purify the obtained residue on a silica gel chromatography column (mobile phase: A-dichloromethane, B-methanol; gradient elution: B%: 0%-10%), and obtain the title product 1h-1 (190 mg, yield: 56%) as a yellow solid.

[0994] MS m / z (ESI): 504.1 [M+1].

[0995] Eighth step

[0996] Dissolve 1h-1 (60.0 mg, 111 μmol) in 4.5 mL ethyleneglycol dimethyl ether, add 1.5 mL methanesulfonic acid and 1.5 mL water, stir at 85 °C for 16 hours. Add the reaction solution dropwise into 10 mL water with stirring, extract with dichloromethane (10 mL x 5), wash the organic phase with 25 mL 0.05 M aqueous hydrochloric acid, filter the aqueous phase, combine all the aqueous extraction phases, adjust the pH of the aqueous phase to 7-8 with saturated potassium bicarbonate solution at 0 °C, extract with a mixed solvent (dichloromethane / methanol: 20 / 3, 15 mL x 5), dry the organic phase over anhydrous sodium sulfate, filter, and concentrate the filtrate under reduced pressure to obtain the crude title product 1i-1 (22 mg) as a brown solid. The product is used directly in the next reaction without purification.

[0997] MS m / z (ESI): 462.1 [M+1].

[0998] Ninth step

[0999] Separate 1i-1 (550 mg, 1.10 mmol) by SFC (separation conditions: column: DAICEL CHIRALPAK IC 250 mm x 50 mm, 10 μm; mobile phase: A-n-hexane: B-ethanol, isocratic elution: B: 45%), to obtain the title product 1i-1-1 (260 mg, yield: 41%) as a yellow solid, and the title product 1i-1-2 (290 mg, yield: 46%) as a yellow solid.

[1000] Single configuration compound 1i-1-1

[1001] SFC analysis: retention time 3.039 min. (column: Chiralpak IC-3 50 x 4.6 mm I.D., 3 μm, mobile phase: A-n-hexane (0.05% isopropylamine), B-ethanol and acetonitrile (0.05% isopropylamine), isocratic elution: B: 45%, flow rate: 1 mL / min, instrument: Shimadzu LC-20AD).

[1002] MS m / z (ESI): 462.3 [M+1].

[1003] Single configuration compound 1i-1-2

[1004] SFC analysis: Retention time 4.951 min. (Chromatographic column: Chiralpak IC-3 50 x 4.6 mm I.D., 3 pm, Mobile phase: A - n-Hexane (0.05% isopropylamine), B - Ethanol and Acetonitrile (0.05% isopropylamine), Isocratic elution: B: 45%, Flow rate: 1 mL / min, Instrument: Shimadzu LC-20AD).

[1005] MS m / z (ESI): 462.3 [M+1].

[1006] Tenth step

[1007] The trifluoroacetate salt of 1i-1-1 (10 mg, 17.93 pmol), trans-3-hydroxycyclobutane-1- carboxylic acid (2.05 mg, 19.73 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (8.18 mg, 21.52 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (9.27 mg, 71.74 pmol) was added and stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (Chromatographic column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; Mobile phase: A - Water (0.1% formic acid), B - Acetonitrile; Gradient elution: B%: 20% - 80%), to obtain the title product 1 (5.51 mg, yield: 53%) as a white solid.

[1008] MS m / z (ESI): 560.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.39 (d, J = 8.8 Hz, 1H), 7.77 (d, J = 11.0 Hz, 1H), 7.36 (s, 1H), 6.58 (s, 1H), 5.60 - 5.52 (m, 1H), 5.47 - 5.34 (m, 2H), 5.20 - 5.08 (m, 2H), 5.07 (d, J = 6.3 Hz, 1H), 4.44 - 4.29 (m, 1H), 3.25 - 3.07 (m, 2H), 2.96 - 2.85 (m, 1H), 2.48 - 2.31 (m, 5H), 2.20 - 1.95 (m, 4H), 1.87 - 1.70 (m, 2H), 0.86 - 0.75 (m, 1H), 0.40 - 0.24 (m, 2H), 0.10 - 0.02 (m, 1H), -0.04 - -0.13 (m, 1H).

[1009] Example 2-2: Preparation of compound 2

[1010] (1S,3R)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin- 1-yl)-3-hydroxycyclobutan-1 -carboxamide 2

[1011] The trifluoroacetate salt of 1i-1-1 (10 mg, 17.93 pmol), cis-3-hydroxycyclobutane-1- carboxylic acid (2.05 mg, 19.73 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'- tetramethyluronium hexafluorophosphate (8.18 mg, 21.52 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (9.27 mg, 71.74 pmol) was added and stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%) to give the title product 2 (6.97 mg, yield: 67%) as a white solid.

[1012] MS m / z (ESI): 560.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.42 (d, J = 8.8 Hz, 1H), 7.77 (d, J = 10.9 Hz, 1H), 7.35 (s, 1H), 6.58 (s, 1H), 5.60 - 5.51 (m, 1H), 5.47 - 5.34 (m, 2H), 5.19 - 5.05 (m, 3H), 4.02 - 3.86 (m, 1H), 3.26 - 3.06 (m, 2H), 2.49 - 2.35 (m, 5H), 2.35 - 2.24 (m, 1H), 2.21 - 2.01 (m, 4H), 1.89 - 1.70 (m, 2H), 0.87 - 0.75 (m, 1H), 0.40 - 0.23 (m, 2H), 0.10 - 0.01 (m, 1H), -0.04 - -0.13 (m, 1H).

[1013] Example 2-3: Preparation of compound 3

[1014] (R)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin- 1-yl)-3-hydroxybutanamide 3

[1015] The trifluoroacetate salt of 1i-1-1 (12 mg, 21.52 pmol), (R)-3-hydroxybutanoic acid (2.46 mg, 23.67 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.82 mg, 25.83 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (11.13 mg, 86.08 pmol) was added, and stirring was performed at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 3 (8.49 mg, yield: 69%) as a white solid.

[1016] MS m / z (ESI): 548.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.42 (d, J = 8.7 Hz, 1H), 7.78 (d, J = 10.9 Hz, 1H), 7.36 (s, 1H), 6.58 (s, 1H), 5.59 - 5.50 (m, 1H), 5.47 - 5.35 (m, 2H), 5.20 (s, 2H), 4.66 (d, J = 4.7 Hz, 1H), 4.15 - 3.96 (m, 1H), 3.25 - 3.06 (m, 2H), 2.43 - 2.36 (m, 3H), 2.35 - 2.26 (m, 1H), 2.26 - 2.04 (m, 3H), 1.89 - 1.68 (m, 2H), 1.09 (d, J = 6.2 Hz, 3H), 0.87 - 0.75 (m, 1H), 0.41 - 0.24 (m, 2H), 0.11 - 0.02 (m, 1H), -0.03 - -0.13 (m, 1H).

[1017] Example 2-4: Preparation of compound 4

[1018] (R)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin- 1-yl)-3-hydroxy-2-methylpropanamide 4

[1019] The trifluoroacetate salt of 1i-1-1 (12 mg, 21.52 pmol), (R)-3-hydroxy-2- methylpropanoic acid (2.46 mg, 23.67 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (9.82 mg, 25.83 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (11.13 mg, 86.08 pmol) was added, and stirring was performed at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 4 (7.73 mg, yield: 64%) as a white solid.

[1020] MS m / z (ESI): 548.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.43 (d, J = 8.8 Hz, 1H), 7.77 (d, J = 10.9 Hz, 1H), 7.36 (s, 1H), 6.58 (s, 1H), 5.62 - 5.50 (m, 1H), 5.48 - 5.33 (m, 2H), 5.25 - 5.08 (m, 2H), 4.72 (t, J = 5.2 Hz, 1H), 3.63 - 3.53 (m, 1H), 3.40 - 3.35 (m, 1H), 3.26 - 3.07 (m, 2H), 2.49 - 2.43 (m, 1H), 2.42 - 2.33 (m, 3H), 2.21 - 2.05 (m, 2H), 1.88 - 1.69 (m, 2H), 1.13 - 0.99 (m, 3H), 0.87 - 0.75 (m, 1H), 0.41 - 0.24 (m, 2H), 0.10 - 0.02 (m, 1H), -0.03 - -0.13 (m, 1H).

[1021] Example 2-5: Preparation of compound 5

[1022] N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b] quinolin-1-yl)-3-hydroxypropanamide 5

[1023] The trifluoroacetate salt of 1i-1-1 (12 mg, 21.52 pmol), 3-hydroxypropanoic acid (2.13 mg, 23.67 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.82 mg, 25.83 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (11.13 mg, 86.08 pmol) was added, and stirring was performed at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 5 (6.52 mg, yield: 55%) as a white solid.

[1024] MS m / z (ESI): 534.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.44 (d, J = 8.7 Hz, 1H), 7.78 (d, J = 11.0 Hz, 1H), 7.36 (s, 1H), 6.59 (s, 1H), 5.62 - 5.50 (m, 1H), 5.49 - 5.34 (m, 2H), 5.21 (s, 2H), 4.60 (t, J = 5.1 Hz, 1H), 3.74 - 3.62 (m, 2H), 3.16 (d, J = 7.0 Hz, 2H), 2.39 (d, J = 1.9 Hz, 3H), 2.33 (t, J = 6.5 Hz, 2H), 2.20 - 2.05 (m, 2H), 1.89 - 1.69 (m, 2H), 0.88 - 0.73 (m, 1H), 0.41 - 0.24 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.13 (m, 1H).

[1025] Example 2-6: Preparation of compound 6

[1026] (S)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b] quinolin-1-yl)-3-hydroxybutanamide 6

[1027] The trifluoroacetate salt of 1i-1-1 (10 mg, 17.93 pmol), (S)-3-hydroxybutanoic acid (2.29 mg, 19.73 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (8.18 mg, 21.52 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (9.27 mg, 71.74 pmol) was added, and stirring was performed at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 6 (6.16 mg, yield: 61%) as a white solid.

[1028] MS m / z (ESI): 548.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.42 (d, J = 8.7 Hz, 1H), 7.79 (d, J = 10.9 Hz, 1H), 7.36 (s, 1H), 6.59 (s, 1H), 5.61 - 5.50 (m, 1H), 5.47 - 5.35 (m, 2H), 5.31 - 5.14 (m, 2H), 4.64 (d, J = 4.6 Hz, 1H), 4.11 - 3.98 (m, 1H), 3.23 - 3.09 (m, 2H), 2.39 (s, 3H), 2.32 - 2.24 (m, 1H), 2.22 - 2.05 (m, 3H), 1.88 - 1.70 (m, 2H), 1.08 (d, J = 6.1 Hz, 3H), 0.87 - 0.74 (m, 1H), 0.40 - 0.24 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.12 (m, 1H).

[1029] Example 2-7: Preparation of compound 7

[1030] (1R,3S)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo- 3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3- hydroxycyclobutane-1-carboxamide 7

[1031] First step

[1032] Dissolve 2-amino-4-fluoro-5-methylbenzaldehyde hydrochloride (138 mg, 686 pmol, prepared using the method disclosed in patent application “WO2022140504 A1”, page 73, example 1) and 1f-1 (200 mg, 686 pmol) in 35 mL of toluene, add 4-methylbenzenesulfonic acid pyridine (103 mg, 412 pmol) and o-methylphenol (596 mg, 5.52 mmol), stir at 135 °C for 3 hours. Concentrate the reaction under reduced pressure, purify the obtained residue by silica gel chromatography column (mobile phase: A dichloromethane, B - methanol; gradient elution: B%: 0%-10%), obtain the title product 7a (213 mg, yield: 73%) as a yellow solid.

[1033] MS m / z (ESI): 407.2 [M+1].

[1034] Second step

[1035] Dissolve 7a (250 mg, 479 pmol) in 12 mL of acetic acid, add hydrogen peroxide (4.41 g, 38.9 mmol, content 30%), stir at 70 °C for 1.5 hours. Quench the reaction at 0 °C with 20 mL of sodium thiosulfate, extract with ethyl acetate (25 mL x 2), wash the organic phase with saturated sodium chloride solution (25 mL x 2), dry the organic phase with anhydrous sodium sulfate, filter, concentrate the filtrate under reduced pressure, purify the obtained residue by silica gel chromatography column (mobile phase: A dichloromethane, B - methanol; gradient elution: B%: 0%-10%), obtain the title product 7b (120 mg, yield: 55%) as a yellow solid.

[1036] MS m / z (ESI): 423.2 [M+1].

[1037] Third step

[1038] Dissolve 7b (120 mg, 263 μmol) in 2 mL of N,N-dimethylformamide, protect under nitrogen, and cool to 0 °C in an ice-water bath. Add oxalyl chloride (167 mg, 1.32 mmol) and stir at 0 °C for 1 h. Pour the reaction into 10 mL of water and collect the solid by filtration. Dry the solid to obtain the title product 7c (115 mg) as a yellow solid. The product is used directly in the next step without purification.

[1039] MS m / z (ESI): 441.1 [M+1].

[1040] Fourth Step

[1041] Dissolve 7c (90.0 mg, 167 μmol) in 3 mL of a mixture of dioxane and 0.2 mL of water. Add potassium N-tert-butyi carbonylmethyl trifluoroborate (198 mg, 838 μmol), 1,1-bis(diphenylphosphino)ferrocene palladium dichloride (24.5 mg, 33.5 μmol), and cesium carbonate (163 mg, 503 μmol). Protect under nitrogen and stir at 105 °C for 5 h. Add 5 mL of water to the reaction and extract with ethyl acetate (8 mL x 3). Dry the organic phase over anhydrous sodium sulfate, filter, and concentrate the filtrate by distillation under reduced pressure to obtain the title product 7d (110 mg) as a yellow solid. The product is used directly in the next step without purification.

[1042] MS m / z (ESI): 536.1 [M+1].

[1043] Fifth Step

[1044] Dissolve 7d (110 mg, 205 μmol) in 3 mL of aqueous hydrochloric acid (6 M) and stir at 40 °C for 10 h. Add 5 mL of water to the reaction and extract with dichloromethane (10 mL x 3). Lyophilize the aqueous phase to obtain the hydrochloride salt of the title product 7e (70 mg) as a yellow solid. The product is used directly in the next step without purification.

[1045] MS m / z (ESI): 436.0 [M+1].

[1046] Sixth Step

[1047] To a solution of 7e (12 mg, 27.56 pmol), trans-3-hydroxycyclobutane-1- carboxylic acid (3.19 mg, 27.56 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 pmol) in 1 mL of N,N- dimethylformamide was added N,N-diisopropylethylamine (14.25 mg, 110.23 pmol) and stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%) to give the title product 7 (5.05 mg, yield: 33%) as a white solid.

[1048] MS m / z (ESI): 534.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.57 (t, J = 5.8 Hz, 1H), 8.31 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.59 (s, 1H), 5.49 - 5.35 (m, 4H), 5.10 - 4.97 (m, 1H), 4.83 (d, J = 5.8 Hz, 2H), 4.29 - 4.18 (m, 1H), 3.32 (s, 3H), 2.89 - 2.79 (m, 1H), 2.31 - 2.21 (m, 2H), 2.02 - 1.91 (m, 2H), 1.89 - 1.80 (m, 1H), 1.80 - 1.69 (m, 1H), 0.86 - 0.75 (m, 1H), 0.41 - 0.25 (m, 2H), 0.11 - 0.03 (m, 1H), -0.04 - -0.12 (m, 1H).

[1049] Example 2-8: Preparation of compound 8

[1050] (1S,3R)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo- 3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3- hydroxycyclobutane-1-carboxamide 8

[1051] Dissolve 7e (12 mg, 27.56 µmol), cis-3-hydroxycyclobutane-1-carboxylic acid (3.19 mg, 27.56 µmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 µmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (14.25 mg, 110.23 µmol), stir at 25 °C for 1 hour. Purify the reaction solution by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 8 (5.14 mg, yield: 34%) in the form of a white solid.

[1052] MS m / z (ESI): 534.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.58 (t, J = 5.8 Hz, 1H), 8.31 (d, J = 8.3 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.59 (s, 1H), 5.52 - 5.28 (m, 4H), 5.09 (d, J = 6.9 Hz, 1H), 4.83 (d, J = 5.8 Hz, 2H), 3.96 - 3.83 (m, 1H), 3.32 (s, 3H), 2.45 - 2.35 (m, 1H), 2.31 - 2.19 (m, 2H), 1.98 - 1.80 (m, 3H), 1.79 - 1.69 (m, 1H), 0.88 - 0.72 (m, 1H), 0.42 - 0.23 (m, 2H), 0.13 - 0.01 (m, 1H), -0.03 - -0.15 (m, 1H).

[1053] Example 2-9: Preparation of compound 9

[1054] (R)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14- tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3-hydroxybutanamide 9

[1055] Dissolve 7e (12 mg, 27.56 µmol), (R)-3-hydroxybutanoic acid (2.86 mg, 27.56 µmol) and 2-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 µmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (14.25 mg, 110.23 µmol), stir at 25 °C for 1 hour. Purify the reaction solution by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 9 (5.36 mg, yield: 36%) as a white solid.

[1056] MS m / z (ESI): 522.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.65 (t, J = 5.8 Hz, 1H), 8.34 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.59 (s, 1H), 5.57 - 5.32 (m, 4H), 4.82 (d, J = 5.8 Hz, 2H), 4.62 (d, J = 4.6 Hz, 1H), 4.01 - 3.88 (m, 1H), 3.33 (s, 3H), 2.28 - 2.19 (m, 1H), 2.17 - 2.08 (m, 1H), 1.89 - 1.80 (m, 1H), 1.80 - 1.69 (m, 1H), 0.99 (d, J = 6.1 Hz, 3H), 0.87 - 0.75 (m, 1H), 0.40 - 0.26 (m, 2H), 0.11 - 0.03 (m, 1H), -0.04 - -0.12 (m, 1H).

[1057] Example 2-10: Preparation of compound 10

[1058] (S)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14- tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3- hydroxybutanamide 10

[1059] Dissolve 7e (12 mg, 27.56 µmol), (S)-3-hydroxybutanoic acid (2.86 mg, 27.56 µmol) and 2-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 µmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (14.25 mg, 110.23 µmol), stir at 25 °C for 1 hour. Purify the reaction solution by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 10 (5.84 mg, yield: 39%) as a white solid.

[1060] MS m / z (ESI): 522.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.64 (t, J = 5.8 Hz, 1H), 8.33 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.59 (s, 1H), 5.54 - 5.34 (m, 4H), 4.81 (d, J = 5.8 Hz, 2H), 4.61 (d, J = 4.6 Hz, 1H), 4.03 - 3.87 (m, 1H), 3.33 (s, 3H), 2.28 - 2.19 (m, 1H), 2.17 - 2.09 (m, 1H), 1.89 - 1.81 (m, 1H), 1.79 - 1.70 (m, 1H), 1.00 (d, J = 6.2 Hz, 3H), 0.88 - 0.75 (m, 1H), 0.41 - 0.25 (m, 2H), 0.11 - 0.02 (m, 1H), -0.03 - -0.12 (m, 1H).

[1061] Example 2-11: Preparation of compound 11

[1062] (R)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14- tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3-hydroxy-2- methylpropanamide 11

[1063] Dissolve 7e (12 mg, 27.56 µmol), (R)-3-hydroxy-2-methylpropanoic acid (2.86 mg, 27.56 µmol) and 2-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 µmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (14.25 mg, 110.23 µmol), stir at 25 °C for 1 hour. Purify the reaction solution by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 11 (5.58 mg, yield: 38%) in the form of a white solid.

[1064] MS m / z (ESI): 522.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.61 (t, J = 5.8 Hz, 1H), 8.33 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.58 (s, 1H), 5.55 - 5.28 (m, 4H), 4.83 (d, J = 5.7 Hz, 2H), 4.63 (t, J = 5.2 Hz, 1H), 3.53 - 3.44 (m, 1H), 3.33 (s, 3H), 3.31 - 3.25 (m, 1H), 2.45 - 2.34 (m, 1H), 1.89 - 1.80 (m, 1H), 1.78 - 1.69 (m, 1H), 0.92 (d, J = 6.9 Hz, 3H), 0.87 - 0.75 (m, 1H), 0.41 - 0.25 (m, 2H), 0.12 - 0.03 (m, 1H), -0.03 - -0.12 (m, 1H).

[1065] Example 2-12: Preparation of compound 12

[1066] (S)-N-((4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14- tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3- hydroxypropanamide 12

[1067] Dissolve 7e (12 mg, 27.56 µmol), 3-hydroxypropanoic acid (2.48 mg, 27.56 µmol) and 2-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 µmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (14.25 mg, 110.23 µmol), stir at 25 °C for 1 hour. Purify the reaction solution by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 12 (4.08 mg, yield: 28%) in the form of a white solid.

[1068] MS m / z (ESI): 508.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.67 (t, J = 5.8 Hz, 1H), 8.35 (d, J = 8.2 Hz, 1H), 7.90 (d, J = 10.7 Hz, 1H), 7.38 (s, 1H), 6.59 (s, 1H), 5.55 - 5.32 (m, 4H), 4.83 (d, J = 5.7 Hz, 2H), 4.56 (t, J = 5.1 Hz, 1H), 3.65 - 3.54 (m, 2H), 3.33 (s, 3H), 2.27 (t, J = 6.4 Hz, 2H), 1.89 - 1.80 (m, 1H), 1.79 - 1.70 (m, 1H), 0.87 - 0.74 (m, 1H), 0.40 - 0.24 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.12 (m, 1H).

[1069] Example 2-13: Preparation of compound 13

[1070] (1R,3S)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1- yl)-3-(hydroxymethyl)cyclobutane-1-carboxamide 13

[1071] To a solution of 1i-1-1 trifluoroacetate salt (12 mg, 21.52 pmol), trans-3- (hydroxymethyl)cyclobutane-1 -carboxylic acid (3.08 mg, 23.67 pmol, prepared using the method disclosed in patent application "WO2021164351 Al" page 47, example 35) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.82 mg, 25.83 pmol) in 1 mL of N,N-dimethylformamide was added N,N-diisopropylethylamine (11.13 mg, 86.08 pmol) and stirred at 25 °C for 1 h. The reaction was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 80%) to give the title product 13 (9.15 mg, yield: 73%) as a white solid.

[1072] MS m / z (ESI): 574.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.34 (d, J = 8.7 Hz, 1H), 7.77 (d, J = 10.9 Hz, 1H), 7.36 (s, 1H), 6.59 (s, 1H), 5.58 - 5.48 (m, 1H), 5.48 - 5.32 (m, 2H), 5.13 (s, 2H), 4.46 (t, J = 5.3 Hz, 1H), 3.37 - 3.34 (m, 2H), 3.24 - 3.08 (m, 2H), 2.98 - 2.86 (m, 1H), 2.38 (s, 3H), 2.34 - 2.21 (m, 1H), 2.19 - 2.01 (m, 4H), 2.00 - 1.89 (m, 2H), 1.87 - 1.70 (m, 2H), 0.87 - 0.74 (m, 1H), 0.41 - 0.24 (m, 2H), 0.10 - 0.02 (m, 1H), -0.04 - -0.14 (m, 1H).

[1073] Example 2-14: Preparation of compound 14

[1074] (1R,3S)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14- dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11- yl)methyl)-3-(hydroxymethyl)cyclobutane-1-carboxamide 14

[1075] To a solution of 7e (12 mg, 27.56 pmol), trans-3-(hydroxymethyl)cyclobutane-1- carboxylic acid (3.59 mg, 27.56 pmol, prepared using the method disclosed in patent application “WO2021164351 Al” page 47, example 35) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 pmol) in 1 mL of N,N- dimethylformamide was added N,N-diisopropylethylamine (14.25 mg, 110.23 pmol) and stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%) to give the title product 14 (7.24 mg, yield: 47%) as a white solid.

[1076] MS m / z (ESI): 548.3 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.51 (t, J = 5.8 Hz, 1H), 8.32 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.59 (s, 1H), 5.53 - 5.32 (m, 4H), 4.81 (d, J = 5.8 Hz, 2H), 4.41 (t, J = 5.3 Hz, 1H), 3.33 (s, 3H), 3.27 (t, J = 5.8 Hz, 2H), 2.92 - 2.81 (m, 1H), 2.30 - 2.18 (m, 1H), 2.07 - 1.96 (m, 2H), 1.89 - 1.70 (m, 4H), 0.88 - 0.73 (m, 1H), 0.40 - 0.26 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.12 (m, 1H).

[1077] Example 2-15: Preparation of compound 15

[1078] (1S,3R)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13- dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)-3-(hydroxymethyl)cyclobutane-1-carboxamide 15

[1079] The trifluoroacetate salt of 1i-1-1 (12 mg, 21.52 pmol), cis-3-(hydroxymethyl)cyclobutane-1 -carboxylic acid (3.08 mg, 23.67 pmol, prepared using the method disclosed in patent application “WO2021164351 Al” page 47, example 35) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.82 mg, 25.83 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (11.13 mg, 86.08 pmol) was added and stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 80%), to obtain the title product 15 (7.93 mg, yield: 64%) as a white solid.

[1080] MS m / z (ESI): 574.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.33 (d, J = 8.7 Hz, 1H), 7.78 (d, J = 10.9 Hz, 1H), 7.36 (s, 1H), 6.59 (s, 1H), 5.65 - 5.51 (m, 1H), 5.47 - 5.33 (m, 2H), 5.22 - 5.08 (m, 2H), 4.55 (t, J = 5.3 Hz, 1H), 3.42 (t, J = 5.8 Hz, 2H), 3.25 - 2.97 (m, 3H), 2.38 (s, 3H), 2.36 - 2.21 (m, 3H), 2.20 - 2.02 (m, 2H), 1.96 - 1.70 (m, 4H), 0.87 - 0.73 (m, 1H), 0.42 - 0.23 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.13 (m, 1H).

[1081] Example 2-16: Preparation of compound 16

[1082] (1S,3R)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo- 3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-3- (hydroxymethyl)cyclobutane-1-carboxamide 16

[1083] A solution of 7e (12 mg, 27.56 pmol), cis-3-(hydroxymethyl)cyclobutane-1- carboxylic acid (3.59 mg, 27.56 pmol, prepared using the method disclosed in patent application “WO2021164351 Al” page 47, example 35) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 pmol) in 1 mL of N,N-dimethylformamide was stirred at 25 °C for 1 hour. N,N-diisopropylethylamine (14.25 mg, 110.23 pmol) was added. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%) to give the title product 16 (5.95 mg, yield: 39%) as a white solid.

[1084] MS m / z (ESI): 548.3 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.52 (t, J = 5.9 Hz, 1H), 8.32 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.37 (s, 1H), 6.59 (s, 1H), 5.51 - 5.30 (m, 4H), 4.82 (d, J = 5.8 Hz, 2H), 4.52 (t, J = 5.3 Hz, 1H), 3.42 - 3.35 (m, 2H), 3.33 (s, 3H), 3.04 - 2.92 (m, 1H), 2.34 - 2.21 (m, 1H), 2.18 - 2.06 (m, 2H), 1.88 - 1.68 (m, 4H), 0.87 - 0.77 (m, 1H), 0.40 - 0.25 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.12 (m, 1H).

[1085] Example 2-17: Preparation of compound 17

[1086] (S)-N-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin- 1-yl)-3-hydroxy-2-methylpropanamide 17

[1087] The trifluoroacetate salt of 1i-1-1 (12 mg, 21.52 pmol), (S)-3-hydroxy-2- methylpropanoic acid (2.46 mg, 23.67 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (9.82 mg, 25.83 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (11.13 mg, 86.08 pmol) was added, and stirring was performed at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 17 (4.08 mg, yield: 33%) as a white solid.

[1088] MS m / z (ESI): 548.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.38 (d, J = 8.6 Hz, 1H), 7.80 (d, J = 11.0 Hz, 1H), 7.36 (s, 1H), 6.59 (s, 1H), 5.62 - 5.51 (m, 1H), 5.48 - 5.34 (m, 2H), 5.30 - 5.15 (m, 2H), 4.61 (t, J = 5.0 Hz, 1H), 3.63 - 3.51 (m, 1H), 3.33 - 3.29 (m, 1H), 3.23 - 3.11 (m, 2H), 2.46 - 2.35 (m, 4H), 2.21 - 2.03 (m, 2H), 1.89 - 1.69 (m, 2H), 1.01 (d, J = 6.8 Hz, 3H), 0.88 - 0.74 (m, 1H), 0.41 - 0.25 (m, 2H), 0.11 - 0.02 (m, 1H), -0.03 - -0.13 (m, 1H).

[1089] Example 2-18: Preparation of compound 18

[1090] (S)-N-(((S)-4-(Cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14- tetrahydro-lH-pyrano[3',4':6,7]indolizino[l,2-b]quinolin-l l-yl)methyl)-3-hydroxy-2- methylpropanamide 18

[1091] Dissolve 7e (12 mg, 27.56 µmol), (S)-3-hydroxy-2-methylpropanoic acid (2.86 mg, 27.56 µmol) and 2-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (11.53 mg, 30.31 µmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (14.25 mg, 110.23 µmol), stir at 25 °C for 1 hour. Purify the reaction solution by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product 18 (2.9 mg, yield: 20%) in the form of a white solid.

[1092] MS m / z (ESI): 522.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.62 (t, J = 5.7 Hz, 1H), 8.34 (d, J = 8.2 Hz, 1H), 7.90 (d, J = 10.8 Hz, 1H), 7.38 (s, 1H), 6.59 (s, 1H), 5.55 - 5.33 (m, 4H), 4.83 (d, J = 5.7 Hz, 2H), 4.63 (t, J = 5.1 Hz, 1H), 3.52 - 3.43 (m, 1H), 3.33 (s, 3H), 3.31 - 3.25 (m, 1H), 2.44 - 2.35 (m, 1H), 1.90 - 1.79 (m, 1H), 1.78 - 1.70 (m, 1H), 0.93 (d, J = 6.9 Hz, 3H), 0.87 - 0.76 (m, 1H), 0.41 - 0.25 (m, 2H), 0.11 - 0.03 (m, 1H), -0.04 - -0.12 (m, 1H).

[1093] Example 2-19: Preparation of compound 19

[1094] (S)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11- yl)methyl)-2-hydroxypropanamide 19

[1095] (S)-2-hydroxypropanoic acid (2.1 mg, 23.3 μmol) was dissolved in 0.5 mL of N,N-dimethylformamide, followed by the addition of 1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate (13.1 mg, 25.2 μmol), N,N-diisopropylethylamine (14.9 mg, 155 μmol) and 7e (10.2 mg, 23.4 μmol) in sequence, stirred at 25 °C for 0.5 h. The reaction solution was concentrated by distillation under reduced pressure, and the obtained residue was purified by pre-HPLC (separation conditions: column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 um, mobile phase: A-water (0.1% formic acid), B-acetonitrile, gradient elution, B%: 10%-70%), to give the title product 19 (5.3 mg, yield: 44.56%) as a white solid.

[1096] MS m / z (ESI): 508.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.71 (t, J = 6.0 Hz, 1H), 8.42 (d, J = 8.3 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.38 (s, 1H), 6.58 (s, 1H), 5.61 (d, J = 4.9 Hz, 1H), 5.49 (d, J = 2.1 Hz, 2H), 5.43 (d, J = 2.6 Hz, 2H), 4.92 - 4.75 (m, 2H), 4.05 - 3.94 (m, 1H), 3.09 - 2.95 (m, 4H), 1.89 - 1.75 (m, 2H), 1.75 - 1.68 (m, 4H), 1.20 (d, J = 6.8 Hz, 3H), 0.86 - 0.76 (m, 1H), 0.41 - 0.25 (m, 2H), 0.11 - 0.02 (m, 1H), -0.04 - -0.13 (m, 1H).

[1097] Example 2-20: Preparation of compound 20

[1098] (R)-N-(((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-2-hydroxypropanamide 20

[1099] (R)-2-hydroxypropanoic acid (2.1 mg, 23.3 pmol) was dissolved in 0.5 mL of N,N-dimethylformamide, followed by the addition of 1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate (13.1 mg, 25.2 pmol), N,N-diisopropylethylamine (14.9 mg, 155 pmol) and 7e (10.2 mg, 23.4 pmol) in sequence, stirred at 25 °C for 0.5 h. The reaction solution was concentrated by distillation under reduced pressure, and the obtained residue was purified by pre-HPLC (separation condition: column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 um, mobile phase: A-water (0.1% formic acid), B-acetonitrile, gradient elution, B%: 10%-70%), to give the title product 20 (3.6 mg, yield: 30.27%) as a white solid.

[1100] MS m / z (ESI): 508.4 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.71 (s, 1H), 8.42 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 10.8 Hz, 1H), 7.38 (s, 1H), 6.59 (s, 1H), 5.61 (d, J = 4.9 Hz, 1H), 5.49 (s, 2H), 5.43 (d, J = 3.0 Hz, 2H), 4.91 - 4.75 (m, 2H), 4.04 - 3.96 (m, 1H), 3.03 - 3.00 (m, 4H), 1.89 - 1.77 (m, 2H), 1.76 - 1.73 (m, 4H), 1.19 (d, J = 6.8 Hz, 3H), 0.85 - 0.76 (m, 1H), 0.40 - 0.25 (m, 2H), 0.12 - 0.03 (m, 1H), -0.04 - -0.13 (m, 1H).

[1101] Example 2-21: Preparation of compound 21

[1102] (S)-N-((4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14-dioxo-3,4,12,14- tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)methyl)-2- hydroxyacetamide 21

[1103] The hydrochloride salt of 7e (30.0 mg, 68.8 μmol) and glycolic acid (5.76 mg, 75.7 μmol) were dissolved in 2 mL of N,N-dimethylformamide, N,N- diisopropylethylamine (26.7 mg, 206 μmol), 1-(3-dimethylaminopropyl)-3- ethylcarbodiimide hydrochloride (19.8 mg, 103 μmol) and 1-hydroxybenzotriazole (13.9 mg, 103 μmol) were added, and stirring was performed at 25 °C for 1.5 hours. 2 mL of water was added to the reaction solution, extraction was performed with dichloromethane (5 mL x 3), the organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated by distillation under reduced pressure, and the obtained residue was purified by pre-HPLC (separation conditions: column: Phenomenex Luna C18 150 x 25 mm x 10 μm, mobile phase: A-water (0.225% formic acid), B-acetonitrile, gradient elution, B%: 19%-49%), to obtain the title product 21 (1.63 mg, yield: 5%) as a yellow solid.

[1104] MS m / z (ESI): 494.3 [M+1]. 1 H NMR (400 MHz, CD3OD) δ 8.34 - 8.29 (m, 1H), 7.83 - 7.77 (m, 1H), 7.73 - 7.70 (m, 1H), 5.64 - 5.58 (m, 1H), 5.56 - 5.49 (m, 2H), 5.44 - 5.37 (m, 1H), 5.07 - 5.01 (m, 2H), 4.06 - 3.99 (m, 2H), 2.62 - 2.51 (m, 3H), 1.95 - 1.83 (m, 2H), 0.93 - 0.88 (m, 1H), 0.50 - 0.38 (m, 2H), 0.15 - 0.08 (m, 1H), 0.07 - -0.01 (m, 1H).

[1105] III. Preparation of intermediate linker-drug conjugates

[1106] Example 3-1: Preparation of LD-1

[1107] N-((4S,12S)-12-benzyl-1-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)- 4-methyl-3,8,11,14,17-pentaoxo-5-oxa-2,7,10,13,16-pentaazaoctadecan-18-yl)-6-(2,5- dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamide LD-1 MS m / z (ESI): 494.3 [M+1]. 1 H NMR (400 MHz, CD3OD) δ 8.34 - 8.29 (m, 1H), 7.83 - 7.77 (m, 1H), 7.73 - 7.70 (m, 1H), 5.64 - 5.58 (m, 1H), 5.56 - 5.49 (m, 2H), 5.44 - 5.37 (m, 1H), 5.07 - 5.01 (m, 2H), 4.06 - 3.99 (m, 2H), 2.62 - 2.51 (m, 3H), 1.95 - 1.83 (m, 2H), 0.93 - 0.88 (m, 1H), 0.50 - 0.38 (m, 2H), 0.15 - 0.08 (m, 1H), 0.07 - -0.01 (m, 1H).

[1105] III. Preparation of intermediate linker-drug conjugates

[1106] Example 3-1: Preparation of LD-1

[1107] N-((4S,12S)-12-benzyl-1-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)- 4-methyl-3,8,11,14,17-pentaoxo-5-oxa-2,7,10,13,16-pentaazaoctadecan-18-yl)-6-(2,5- dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamide LD-1 MS m / z (ESI): 494.3 [M+1]. 1 H NMR (400 MHz, CD3OD) δ 8.34 - 8.29 (m, 1H), 7.83 - 7.77 (m, 1H), 7.73 - 7.70 (m, 1H), 5.64 - 5.58 (m, 1H), 5.56 - 5.49 (m, 2H), 5.44 - 5.37 (m, 1H), 5.07 - 5.01 (m, 2H), 4.06 - 3.99 (m, 2H), 2.62 - 2.51 (m, 3H), 1.95 - 1.83 (m, 2H), 0.93 - 0.88 (m, 1H), 0.50 - 0.38 (m, 2H), 0.15 - 0.08 (m, 1H), 0.07 - -0.01 (m, 1H).

[1108] LD-1a (10 mg, 15.87 µmol, prepared by the method disclosed in patent application “WO2023178641 A1” page 40, example 10) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (6.63 mg, 17.46 µmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (10.25 mg, 79.36 µmol) and 7e (6.90 mg, 15.87 µmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-1 (7.05 mg, yield: 41%) as a white solid.

[1109] MS m / z (ESI): 1048.9 [M+1].

[1110] Example 3-2: Preparation of LD-2

[1111] N-((S)-12-benzyl-1-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14- dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)-3,8,11,14,17- pentoxy-5-oxa-2,7,10,13,16-pentazaoctadec-18-yl)-1-(4-(2-(methylsulfonyl)pyrimidin-5-yl)but-3-yn-1- yl)cyclopropane-1-carboxamide LD-2

[1112] First step

[1113] LD-2a (2.20 g, 12.1 mmol, prepared by the method disclosed in patent application “WO2020077038 A1” page 62, example 4), silver nitrite (111 mg, 724 µmol), bis(benzonitrile)palladium(II) chloride (555 mg, 1.45 mmol), nitromethane (4.90 g, 80.3 mmol) and copper(II) chloride dihydrate (247 mg, 1.45 mmol) were dissolved in 44 mL of tert-butanol, oxygen was replaced three times, and stirred at 25°C for 12 hours under oxygen. 150 mL of water was added to the reaction solution at 25°C, extracted with dichloromethane (50 mL x 3), the organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated by distillation under reduced pressure. The obtained residue was purified by silica gel column chromatography with developing system B to obtain the title product LD-2b (800 mg, yield: 33%) as a white solid.

[1114] Second step

[1115] LD-2b (800 mg, 4.04 mmol) was dissolved in 24 mL of methanol, then potassium carbonate (1.12 g, 8.07 mmol) and (1-diazo-2-oxopropyl) dimethyl phosphonate (930 mg, 4.84 mmol) were added, and stirred at 25°C for 12 hours. 50 mL of water was added to the reaction solution, extracted with ethyl acetate (20 mL x 3), the organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated by distillation under reduced pressure. The obtained residue was purified by silica gel column chromatography with developing system B to obtain the title product LD-2c (650 mg, yield: 83%) as a white solid.

[1116] Third step

[1117] LD-2c (650 mg, 3.35 mmol), 5-bromo-2-mercapto pyrimidine (686 mg, 3.35 mmol), triethylamine (3.39 g, 33.4 mmol), cuprous iodide (63.7 mg, 334 µmol) and bis(triphenylphosphine)palladium(II) chloride (244 mg, 349 µmol) were dissolved in 10 mL of tetrahydrofuran, replaced with nitrogen three times, and stirred at 60°C for 2 hours under nitrogen protection. The reaction solution was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography with developing system B to obtain the title product LD-2d (770 mg, yield: 68%) as a white solid.

[1118] MS m / z (ESI): 319.6 [M+1].

[1119] Fourth step

[1120] LD-2d (1.80 g, 5.65 mmol) was dissolved in 20 mL of dichloromethane, then m-chloroperoxybenzoic acid (2.87 g, 14.1 mmol, purity 85.0%) was added, stirred at 25°C for 2 hours. The reaction solution was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography with developing system B to obtain the title product LD-2e (1.70 g, yield: 85%) as a white solid.

[1121] MS m / z (ESI): 351.1 [M+1].

[1122] Fifth step

[1123] LD-2e (500 mg, 1.43 mmol) was dissolved in 6 mL of dichloromethane, then trifluoroacetic acid (2.30 g, 20.2 mmol) was added, stirred at 25°C for 2 hours. The reaction solution was concentrated under reduced pressure to obtain the crude title product LD-2f (418 mg) as a white solid. The product was directly used in the next step without purification.

[1124] MS m / z (ESI): 295.2 [M+1].

[1125] Sixth step

[1126] LD-2f (340 mg, 1.16 mmol) was dissolved in 5 mL of acetonitrile, then 2-(7-azobenzo-triazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (448 mg, 1.18 mmol) was added, stirred at 25°C for 15 minutes. Then the above reaction solution was slowly added dropwise into a solution of LD-2g (538 mg, 1.16 mmol, prepared by the method disclosed in patent application "WO2014057687 A1", page 267, example 74) in acetonitrile / water (1 / 2, 5 mL), after addition, the reaction was stirred at 25°C for 0.5 hours. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2x150mm, 4μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-55%), to obtain the title product LD-2h (703 mg, yield: 86%) as a white solid.

[1127] MS m / z (ESI): 698.3 [M-1].

[1128] Seventh step

[1129] Dissolve 7e (10 mg, 22.96 pmol), LD-2h (16.07 mg, 22.96 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.61 mg, 25.25 pmol) in 1 mL of N,N-dimethylformamide, add N,N-diisopropylethylamine (11.87 mg, 91.84 pmol), stir the reaction at 25 °C for 1 hour. Purify the reaction by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-60%) to give the title product LD-2 (9.35 mg, yield: 36%) as a white solid.

[1130] MS m / z (ESI): 1117.8 [M+1].

[1131] Example 3-3: Preparation of LD-3

[1132] N-(((S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH,12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-6-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)hexanamide LD-3

[1133] LD-3a (15 mg, 24.35 pmol, prepared by the method disclosed in patent application “WO2014057687 A1” page 267, example 74) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (10.17 mg, 26.78 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (15.73 mg, 121.75 pmol) and the trifluoroacetate salt of 1i-1-1 (14.03 mg, 24.35 pmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (chromatography column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-3 (17.31 mg, yield: 65%) as a white solid.

[1134] MS m / z (ESI): 1060.9 [M+1].

[1135] Example 3-4: Preparation of LD-4

[1136] N-((S)-12-benzyl-l-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14- dioxo-3,4,12,14-tetrahydro-lH-pyrano[3',4':6,7]indolizino[l,2-b]quinolin-l l-yl)-3,8,11,14,17- pentoxy-5-oxa-2,7,10,13,16-pentaazaoctadecan-18-yl)-6-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l- yl)hexanamide LD-4

[1137] LD-3a (12 mg, 19.48 pmol, prepared by the method disclosed in patent application “WO2014057687 A1” page 267, example 74) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (8.14 mg, 21.42 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (12.58 mg, 97.40 pmol) and 7e (10.59 mg, 19.48 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-60%), to obtain the title product LD-4 (11.25 mg, yield: 55%) in the form of a white solid.

[1138] MS m / z (ESI): 1034.8 [M+1].

[1139] Example 3-5: Preparation of LD-5

[1140] N-(((S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH,12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-6-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)hexanamide LD-5

[1141] First step

[1142] LD-2g (80 mg, 0.19 mmol, prepared using the method disclosed in Example 74, page 267 of the patent application “WO2014057687 A1”) and sodium carbonate (20.03 mg, 0.19 mmol) were dissolved in 2 mL of water, then a solution of LD-5a (79.42 mg, 0.28 mmol) in acetonitrile (2 mL) was added dropwise slowly, after the addition was completed, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%), to obtain the title product LD-5b (48 mg, yield: 41%) in the form of a white solid.

[1143] MS m / z (ESI): 587.4 [M-1].

[1144] Second step

[1145] LD-5b (14 mg, 23.81 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.95 mg, 26.19 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (15.38 mg, 119.04 μmol) and the trifluoroacetate salt of 1i-1-1 (13.72 mg, 23.81 μmol) were added in turn, and the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-5 (14.31 mg, yield: 57%) in the form of a white solid.

[1146] MS m / z (ESI): 1032.9 [M+1].

[1147] Example 3-6: Preparation of LD-6

[1148] N-(((S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH,12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-5-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)pentanamide LD-6

[1149] First step

[1150] LD-2g (80 mg, 0.19 mmol, prepared using the method disclosed in example 74, page 267 of the patent application "WO2014057687 Al") and sodium carbonate (20.03 mg, 0.19 mmol) were dissolved in 2 mL of water, then a solution of LD-6a (83.39 mg, 0.28 mmol) in acetonitrile (2 mL) was added slowly dropwise, after the addition, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 50%), to obtain the title product LD-6b (45 mg, yield: 38%) as a white solid.

[1151] MS m / z (ESI): 601.4 [M-1].

[1152] Second step

[1153] LD-6b (15 mg, 24.91 pmol) and 2-(7-azobenzo-triazol-l-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (10.41 mg, 27.40 pmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (16.09 mg, 124.58 pmol) and the trifluoroacetate salt of li-1-1 (14.35 mg, 24.91 pmol) were added in turn, the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 65%), to obtain the title product LD-6 (13.50 mg, yield: 51%) as a white solid.

[1154] MS m / z (ESI): 1046.9 [M+1].

[1155] Example 3-7: Preparation of LD-7

[1156] (S)-N-(2-(R)-1-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxy-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-1-oxoprop-2-yl)oxy)methyl)amino)-2-oxoethyl)-2-(19-(2,5-dioxo- 2,5-dihydro-1H-pyrrol-1-yl)-4,7,17-trioxo-10,13-dioxo-3,6,16-triazapentadecanoyl)amido) LD-7

[1157] First step

[1158] LD-7b (70 mg, 0.16 mmol, prepared according to the method disclosed in the reference patent application “WO2023178641 A1” page 38 example 9) and sodium carbonate (16.96 mg, 0.16 mmol) were dissolved in 2 mL of water, then a solution of LD-7a (68.07 mg, 0.16 mmol) in acetonitrile (2 mL) was added slowly dropwise, after the addition, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%), to obtain the title product LD-7c (89 mg, yield: 69%) as a white solid.

[1159] MS m / z (ESI): 746.4 [M-1].

[1160] Second step

[1161] LD-7c (13 mg, 17.40 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.27 mg, 19.14 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.24 mg, 87.01 pmol) and the trifluoroacetate salt of 1i-1-1 (10.02 mg, 17.40 pmol) were added in turn, and the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%) to obtain the title product LD-7 (13.14 mg, yield: 62%) as a white solid.

[1162] MS m / z (ESI): 1091.9 [M+1].

[1163] Example 3-8: Preparation of LD-8

[1164] N-((2R,10S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH,12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-2-methyl-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-4-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)butanamide LD-8

[1165] First step

[1166] LD-7b (50 mg, 0.11 mmol, prepared according to the method disclosed in the patent application “WO2023178641 A1”, page 38, example 9) and sodium carbonate (12.12 mg, 0.11 mmol) were dissolved in 2 mL of water, then a solution of LD-5a (48.05 mg, 0.17 mmol) in acetonitrile (2 mL) was slowly added dropwise, after which the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%) to obtain the title product LD-8a (44 mg, yield: 60%) as a white solid.

[1167] MS m / z (ESI): 601.5 [M-1].

[1168] Second step

[1169] LD-8a (12 mg, 19.93 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (8.33 mg, 21.92 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (12.87 mg, 99.66 pmol) and the trifluoroacetate salt of 1i-1-1 (11.48 mg, 19.93 pmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-70%), to obtain the title product LD-8 (10.08 mg, yield: 47%) in the form of a white solid.

[1170] MS m / z (ESI): 1046.9 [M+1].

[1171] Example 3-9: Preparation of LD-9

[1172] N-((2S,10S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH,12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-2-methyl-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-4-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)butanamide LD-9

[1173] First step

[1174] LD-9a (50 mg, 0.11 mmol, prepared using the method disclosed in patent application “WO2023178641 A1” page 38, example 9) and sodium carbonate (12.12 mg, 0.11 mmol) were dissolved in 2 mL of water, then a solution of LD-5a (48.05 mg, 0.17 mmol) in acetonitrile (2 mL) was added dropwise slowly, after the addition, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%), to obtain the title product LD-9b (36 mg, yield: 49%) as a white solid.

[1175] MS m / z (ESI): 601.5 [M-1].

[1176] Second step

[1177] LD-9b (12 mg, 19.93 pmol) and 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (8.33 mg, 21.92 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropyl ethylamine (12.87 mg, 99.66 pmol) and the trifluoroacetate salt of 1i-1-1 (11.48 mg, 19.93 pmol) were added in turn, and the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-70%), to obtain the title product LD-9 (15.12 mg, yield: 71%) as a white solid.

[1178] MS m / z (ESI): 1046.9 [M+1].

[1179] Example 3-10: Preparation of LD-10

[1180] (S)-N-(2-((((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1- yl)amino)-2-oxoethoxy)methyl)amino)2-oxoethyl)-2-(19-(2,5-dioxo-2,5-dihydro-1H-pyrrol- 1-yl)-4,7,17-trioxo-10,13-dioxa-3,6,16-triazacyclododecanoylamino)-3-phenylpropanamide LD-10

[1181] First step

[1182] LD-2g (70 mg, 0.17 mmol, prepared using the method disclosed in Example 74, page 267 of the patent application “WO2014057687 A1”) and sodium carbonate (17.52 mg, 0.17 mmol) were dissolved in 2 mL of water, then a solution of LD-7a (70.32 mg, 0.17 mmol) in acetonitrile (2 mL) was added dropwise slowly, after the addition, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%), to obtain the title product LD-10a (86 mg, yield: 65%) as a white solid.

[1183] MS m / z (ESI): 732.5 [M-1].

[1184] Second step

[1185] LD-10a (13 mg, 17.73 pmol) and 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.41 mg, 19.50 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropyl ethylamine (11.45 mg, 88.67 pmol) and the trifluoroacetate salt of 1i-1-1 (10.21 mg, 17.73 pmol) were added sequentially, the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-10 (12.53 mg, yield: 58%) as a white solid.

[1186] MS m / z (ESI): 1178.0 [M+1].

[1187] Example 3-11: Preparation of LD-11

[1188] (S)-N-(2-(R)-1-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxy-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-1-oxoprop-2-yl)oxy)methyl)amino)-2-oxoethyl)-2-(19-(2,5-dioxo- 2,5-dihydro-1H-pyrrol-1-yl)-4,7,17-trioxo-10,13-dioxo-3,6,16-triazapentadecanoyl)amido) LD-11

[1189] First step

[1190] LD-9a (80 mg, 0.18 mmol, prepared using the method disclosed in Example 9, page 38 of the patent application “WO2023178641 A1”) and sodium carbonate (19.38 mg, 0.18 mmol) were dissolved in 2 mL of water, then a solution of LD-7a (77.79 mg, 0.18 mmol) in acetonitrile (2 mL) was added slowly dropwise, after which the reaction was stirred at 25 °C for 0.5 hours. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 50%), to obtain the title product LD-11a (75 mg, yield: 54%) as a white solid.

[1191] MS m / z (ESI): 746.6 [M-1].

[1192] Second step

[1193] LD-11a (13 mg, 17.40 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.27 mg, 19.14 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.24 mg, 87.01 pmol) and the trifluoroacetate salt of 1i-1-1 (10.02 mg, 17.40 pmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-70%), to obtain the title product LD-11 (13.14 mg, yield: 62%) as a white solid.

[1194] MS m / z (ESI): 1192.0 [M+1].

[1195] Example 3-12: Preparation of LD-12

[1196] (S)-N-(2-((((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1- yl)amino)-2-oxoethoxy)methyl)amino)2-oxoethyl)-2-(15-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)-4,7-dioxo-10,13-oxo-3,6-diazapentadecanamide)-3-phenylpropanamide LD-12

[1197] First step

[1198] LD-12a (60 mg, 0.11 mmol, prepared using the method disclosed in patent application “WO2019044947 A1” page 119, example 18), trifluoroacetate salt of 1i-1-1 (69 mg, 0.11 mmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (45 mg, 0.12 mmol) were dissolved in 3 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (56 mg, 0.43 mmol) was added and the reaction was stirred at 25 °C for 1 h. The reaction was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 30% - 90%) to give the title product LD-12b (101 mg, yield: 79%) as a white solid.

[1199] MS m / z (ESI): 1089.9 [M+1].

[1200] Second step

[1201] LD-12b (101 mg, 92.73 pmol) was dissolved in 2 mL of N,N-dimethylformamide, 1,8-diazabicyclo[5.4.0]undec-7-ene (14.12 mg, 92.73 pmol) was added and the reaction was stirred at 25 °C for 1 h. The reaction was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 80%) to give the title product LD-12c (56 mg, yield: 68%) as a white solid.

[1202] MS m / z (ESI): 867.7 [M+1].

[1203] Third step

[1204] LD-12c (10 mg, 11.54 pmol), LD-12d (3.26 mg, 12.69 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.26 mg, 13.84 pmol) were dissolved in 1 mL of N,N-dimethylformamide, N,N-diisopropylethylamine (4.47 mg, 34.61 pmol) was added, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-60%), to obtain the title product LD-12 (6.71 mg, yield: 52%) as a white solid.

[1205] MS m / z (ESI): 1107.2 [M+1].

[1206] Example 3-13: Preparation of LD-13

[1207] N-((S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-lH,12H-benzo[de]pyrano[3',4':6,7]indolizino[l,2- b]quinolin-l-yl)amino)-l,6,9,12,15-pentaoxo-3-oxo-5,8,11,14-tetraazahexadecan-16-yl)-7-(2,5- dioxo-2,5-dihydro-lH-pyrrol-l-yl)heptanamide LD-13

[1208] First step

[1209] LD-2g (40 mg, 0.12 mmol, prepared by the method disclosed in patent application “WO2014057687 A1” page 267, example 74) and sodium carbonate (13.16 mg, 0.12 mmol) were dissolved in 2 mL of water, then a solution of LD-13a (68.31 mg, 0.16 mmol, prepared by the method disclosed in patent application “WO2023018199 A1” page 53, example 9) in acetonitrile (2 mL) was added dropwise slowly, after completion of addition, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%), to obtain the title product LD-13b (48 mg, yield: 60%) as a white solid.

[1210] MS m / z (ESI): 629.5 [M-1].

[1211] Second step

[1212] LD-13b (13 mg, 20.63 µmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (8.62 mg, 22.69 µmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (13.33 mg, 103.17 µmol) and the trifluoroacetate salt of 1i-1-1 (11.89 mg, 20.63 µmol) were added in turn, and the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-70%), to obtain the title product LD-13 (14.35 mg, yield: 63%) as a white solid.

[1213] MS m / z (ESI): 1175.0 [M+1].

[1214] Example 3-14: Preparation of LD-14

[1215] N-((4R, 12S)-12-benzyl-l-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3, 14-dioxo-3, 4, 12, 14-tetrahydro-lH-pyrano[3', 4':6, 7]indolizino[l, 2-b]quinolin-l l- yl)-4-methyl-3, 8, 11, 14, 17-pentaoxo-5-oxa-2, 7, 10, 13, 16-pentaazaoctadecan-18-yl)- 6-(2, 5-dioxo-2, 5-dihydro-lH-pyrrol-l-yl)hexanamide LD-14

[1216] LD-14a (14.48 mg, 22.96 pmol, prepared using the method disclosed in patent application “WO2023178641 A1” Example 10, page 40) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (9.61 mg, 25.26 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.87 mg, 91.86 pmol) and 7e (10 mg, 22.96 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-60%), to obtain the title product LD-14 (6.98 mg, yield: 29%) in the form of a white solid.

[1217] MS m / z (ESI): 1048.9 [M+1].

[1218] Example 3-15: Preparation of LD-15

[1219] N-((7S, 10S, 13S)-l-(((lS, 9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10, 13-dioxo-2, 3, 9, 10, 13, 15-hexahydro-lH, 12H-benzo[de]pyrano[3', 4':6, 7]indolizino[l, 2-b]quinolin-l-yl)amino)-7, 10-dimethyl-l, 6, 9, 12-tetraoxo-3-oxa-5, 8, 11- triazatetradecan-13-yl)-6-(2, 5-dioxo-2, 5-dihydro-lH-pyrrol-l-yl)hexanamide LD-15

[1220] LD-15a (10 mg, 19.55 pmol, prepared by the method disclosed in patent application “WO2020219287 A1” page 151, example 14) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (8.18 mg, 21.50 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (12.60 mg, 97.75 pmol) and the trifluoroacetate salt of 1i-1-1 (11.25 mg, 19.55 pmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (chromatography column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-70%), to obtain the title product LD-15 (5.54 mg, yield: 29%) in the form of a white solid.

[1221] MS m / z (ESI): 955.9 [M+1].

[1222] Example 3-16: Preparation of LD-16

[1223] N-((9S,12S,15S)-1-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl-3,14- dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)-9,12- dimethyl-3,8,11,14-tetraoxo-5-oxa-2,7,10,13-tetraazahexadec-15-yl)-6-(2,5-dioxo-2,5- dihydro-1H-pyrrol-1-yl)hexanamide LD-16

[1224] First step

[1225] LD-15a (10 mg, 19.55 pmol, prepared using the method disclosed in patent application “WO2020219287 A1” page 151, example 14) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (8.18 mg, 21.50 pmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (12.60 mg, 97.75 pmol) and 7e (8.51 mg, 19.55 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 70%), to obtain the title product LD-16 (3.79 mg, yield: 20%) in the form of a white solid.

[1226] MS m / z (ESI): 929.9 [M+1].

[1227] Example 3-17: Preparation of LD-17

[1228] N-((4R,12S)-12-benzyl-l-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3,14-dioxo-3,4,12,14-tetrahydro-lH-pyrano[3',4':6,7]indolizino[l,2-b]quinolin-l l-yl)- 4-methyl-3,8,11,14,17-pentaoxo-5-oxa-2,7,10,13,16-pentaazaoctadecan-18-yl)-4-(2,5- dioxo-2,5-dihydro-lH-pyrrol-l-yl)butanamide LD-17

[1229] LD-8a (13.84 mg, 22.96 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.61 mg, 25.26 pmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (11.87 mg, 91.86 pmol) and 7e (10 mg, 22.96 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 65%), to obtain the title product LD-17 (7.12 mg, yield: 30%) in the form of a white solid.

[1230] MS m / z (ESI): 1021.0 [M+1].

[1231] Example 3-18: Preparation of LD-18

[1232] N-((4S,12S)-12-benzyl-l-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3, 14-dioxo-3, 4, 12, 14-tetrahydro-lH-pyrano[3',4':6,7]indolizino[l,2-b]quinolin-l l- yl)-4-methyl-3, 8, 11, 14, 17-pentaoxo-5-oxa-2, 7, 10, 13, 16-pentaazaoctadecan-18- yl)-4-(2, 5-dioxo-2, 5-dihydro-lH-pyrrol-l-yl)butanamide LD-18

[1233] LD-9b (13.84 mg, 22.96 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.61 mg, 25.26 μmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (11.87 mg, 91.86 μmol) and 7e (10 mg, 22.96 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-18 (6.33 mg, yield: 26%) in the form of a white solid.

[1234] MS m / z (ESI): 1020.9 [M+1].

[1235] Example 3-19: Preparation of LD-19

[1236] N-((4R,12S)-12-benzyl-l-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3, 14-dioxo-3, 4, 12, 14-tetrahydro-lH-pyrano[3',4':6,7]indolizino[l,2-b]quinolin-l l- yl)-4-methyl-3, 8, 11, 14, 17-pentaoxo-5-oxa-2, 7, 10, 13, 16-pentaazaoctadecan-18- yl)-5-(2, 5-dioxo-2, 5-dihydro-lH-pyrrol-l-yl)pentanamide LD-19

[1237] First Step

[1238] LD-7b (100 mg, 0.23 mmol, prepared using the method disclosed in patent application “WO2023178641 A1” page 38, example 9) and sodium carbonate (24.23 mg, 0.23 mmol) were dissolved in 2 mL of water, then a solution of LD-6a (73.99 mg, 0.25 mmol) in acetonitrile (2 mL) was added dropwise slowly, after the addition was completed, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%), to obtain the title product LD-19a (116 mg, yield: 82%) in the form of a white solid.

[1239] MS m / z (ESI): 615.5 [M-1].

[1240] Second Step

[1241] LD-19a (14.16 mg, 22.96 µmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.61 mg, 25.26 µmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.87 mg, 91.86 µmol) and 7e (10 mg, 22.96 µmol) were added in turn, and the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-19 (7.77 mg, yield: 31%) in the form of a white solid.

[1242] MS m / z (ESI): 1035.1 [M+1].

[1243] Example 3-20: Preparation of LD-20

[1244] N-((4S,12S)-12-benzyl-1-((S)-4-(cyclopropylmethyl)-8-fluoro-4-hydroxy-9-methyl- 3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-11-yl)- 4-methyl-3,8,11,14,17-pentaoxo-5-oxa-2,7,10,13,16-pentaazaoctadecan-18-yl)-5-(2,5- dioxo-2,5-dihydro-1H-pyrrol-1-yl)pentanamide LD-20

[1245] First step

[1246] LD-9a (100 mg, 0.23 mmol, prepared using the method disclosed in patent application “WO2023178641 A1” Example 9, page 38) and sodium carbonate (24.23 mg, 0.23 mmol) were dissolved in 2 mL of water, then a solution of LD-6a (63.90 mg, 0.22 mmol) in acetonitrile (2 mL) was added slowly dropwise, after completion of the addition, the reaction was stirred at 25 °C for 0.5 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 50%), to obtain the title product LD-20a (88 mg, yield: 62%) as a white solid.

[1247] MS m / z (ESI): 615.5 [M-1].

[1248] Second step

[1249] LD-20a (14.16 mg, 22.96 pmol) and 2-(7-azobenzo-triazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (9.61 mg, 25.26 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.87 mg, 91.86 pmol) and 7e (10 mg, 22.96 pmol) were added sequentially, the reaction was stirred at 25 °C for 1 h. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 65%), to obtain the title product LD-20 (7.94 mg, yield: 32%) as a white solid.

[1250] MS m / z (ESI): 1035.0 [M+1].

[1251] Example 3-21: Preparation of LD-21

[1252] N-((2R,10S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10, 13-dioxo-2,3,9,10,13,15-hexahydro-lH, 12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-2-methyl-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-5-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)pentanamide LD-21

[1253] LD-19a (11.79 mg, 19.11 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.93 mg, 20.85 μmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropyl ethylamine (8.98 mg, 69.50 μmol) and the trifluoroacetate salt of 1i-1-1 (10 mg, 17.38 μmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-21 (15.05 mg, yield: 78%) in the form of a white solid.

[1254] MS m / z (ESI): 1061.0 [M+1].

[1255] Example 3-22: Preparation of LD-22

[1256] N-((2S,10S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH, 12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-2-methyl-l,6,9,12,15-pentaoxo-3-oxa-5,8,11,14- tetraazahexadec-16-yl)-5-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)pentanamide LD-22

[1257] First Step

[1258] LD-20a (11.79 mg, 19.11 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.93 mg, 20.85 μmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (8.98 mg, 69.50 μmol) and the trifluoroacetate salt of li-l-l (10 mg, 17.38 μmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-22 (16.96 mg, yield: 90%) in the form of a white solid.

[1259] MS m / z (ESI): 1060.9 [M+1].

[1260] Example 3-23: Preparation of LD-23

[1261] N-((7S,15R)-7-benzyl 17-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-lH, 12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-15-methyl-2,5,8,11,17-pentaoxo-14-oxa-3,6,9,12- tetraazahexadecyl)-6-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)hexanamide LD-23

[1262] First Step

[1263] To a solution of LD-23a (140 mg, 278.57 pmol, prepared using the method disclosed in patent application “WO2023186015 A1” page 38, example X2) in N,N-dimethylacetamide (3 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (21.20 mg, 139.28 pmol) under nitrogen atmosphere and the resulting mixture was stirred at 25 °C for 1 h. To this was then added 1-hydroxybenzotriazole monohydrate (45.17 mg, 334.28 pmol), LD-23b (146.70 mg, 292.50 pmol) and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (58.74 mg, 306.43 pmol) and the resulting mixture was stirred at 25 °C for 3 h. The reaction was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 90%) to get the title product LD-23c (141 mg, yield: 66%) as a white solid.

[1264] MS m / z (ESI): 764.4 [M+1].

[1265] Second step

[1266] To a solution of LD-23c (140 mg, 183.28 pmol) in methanol (4 mL) and tetrahydrofuran (4 mL) was added 10% palladium on carbon (30 mg) and the resulting mixture was stirred at 25 °C under hydrogen atmosphere at normal pressure for 1 h. The reaction was filtered and the filter cake was washed with methanol (10 mL) and then the filtrate was concentrated under reduced pressure. The concentrated residue was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 80%) to get the title product LD-23d (63 mg, yield: 51%) as a white solid.

[1267] MS m / z (ESI): 672.5 [M-1].

[1268] Third step

[1269] LD-23d (63 mg, 93.51 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'- tetramethyluronium hexafluorophosphate (42.67 mg, 112.21 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (36.18 mg, 280.53 pmol) and the trifluoroacetate salt of 1i-1-1 (53.76 mg, 93.51 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by C18 reverse-phase column chromatography (mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-90%), to give the title product LD-23e (80 mg, yield: 76%) as a white solid.

[1270] MS m / z (ESI): 1118.1 [M+1].

[1271] Fourth step

[1272] To a solution of LD-23e (30 mg, 26.85 pmol) in N,N-dimethylacetamide (1 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (4.08 mg, 26.85 pmol) under a nitrogen atmosphere, and the resulting mixture was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-80%), to give the title product LD-23f (15 mg, yield: 62%) as a white solid.

[1273] MS m / z (ESI): 895.8 [M+1].

[1274] Fifth step

[1275] LD-23g (3.54 mg, 16.76 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (7.65 mg, 20.11 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (6.48 mg, 50.28 μmol) and LD-23f (15 mg, 16.76 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-23 (11.63 mg, yield: 63%) in the form of a white solid.

[1276] MS m / z (ESI): 1089.0 [M+1].

[1277] Example 3-24: Preparation of LD-24

[1278] N-((7S,15R)-7-benzyl 17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-15-methyl-2,5,8,11,17-pentaoxo-14-oxa- 3,6,9,12-tetraazheptadecyl)-5-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)pentanamide LD-24

[1279] LD-24a (2.64 mg, 13.41 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (5.95 mg, 15.64 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (7.20 mg, 55.87 μmol) and LD-23f (10 mg, 11.17 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-24 (7.42 mg, yield: 61%) in the form of a white solid.

[1280] MS m / z (ESI): 1075.0 [M+1].

[1281] Example 3-25: Preparation of LD-25

[1282] N-((7S,15R)-7-benzyl 17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-15-methyl-2,5,8,11,17-pentaoxo-14-oxa-3,6,9,12- tetraazheptadecyl)-4-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)butanamide LD-25

[1283] LD-25a (2.46 mg, 13.41 μmol) and 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.95 mg, 15.64 μmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropyl ethylamine (7.20 mg, 55.87 μmol) and LD-23f (10 mg, 11.17 μmol) were added in turn, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-25 (6.98 mg, yield: 58%) in the form of a white solid.

[1284] MS m / z (ESI): 1060.9 [M+1].

[1285] Example 3-26: Preparation of LD-26

[1286] (R)-3-(((S)-7-benzyl-23-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3,6,9,12,5- pentaoxo-18,21-dioxa-2,5,8,11,14-pentaazatridecyl)oxy)-N-((1S,9S)-9-(cyclopropylmethyl)- 5-fluoro-9-hydroxy-4-methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H- benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1-yl)butanamide LD-26

[1287] LD-12d (3.10 mg, 12.07 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.35 mg, 14.08 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (6.48 mg, 50.28 pmol) and LD-23f (9 mg, 10.06 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-26 (7.88 mg, yield: 69%) in the form of a white solid.

[1288] MS m / z (ESI): 1134.9 [M+1].

[1289] Example 3-27: Preparation of LD-27

[1290] N-(((S)-7-benzyl-17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-2,5,8,11,17-pentaoxo-14-oxo-3,6,9,12-tetraazheptadecyl)-4-(2,5-dioxo- 2,5-dihydro-1H-pyrrol-1-yl)butanamide LD-27

[1291] First step

[1292] LD-27a (534.34 mg, 1.45 mol, prepared using the method disclosed in patent application “WO2014057687 A1”, page 239, example 58) and LD-27b (220 mg, 1.21 mol, prepared using the method disclosed in patent application “WO2023125530 A1”, page 136, example 73) were dissolved in 2 mL of dichloromethane, then trifluoroacetic acid (0.5 mL) was added, after addition, the reaction was stirred at 25 °C for 1 hour. The reaction solution was concentrated under reduced pressure, and the residue was purified by C18 reverse phase column (mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-90%), to obtain the title product LD-27c (320 mg, yield: 71%) in the form of a white solid.

[1293] MS m / z (ESI): 489.3 [M+1].

[1294] Second step

[1295] To a solution of LD-27c (320 mg, 0.63 pmol) in N,N-dimethylformamide (5 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (47.92 mg, 0.31 mmol) under nitrogen atmosphere and the resulting mixture was stirred at 25 °C for 1 h. Then to this was added 1-hydroxybenzotriazole monohydrate (102.07 mg, 0.76 mmol), LD-23b (331.15 mg, 0.66 mmol) and l-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (132.74 mg, 0.69 pmol) and the resulting mixture was stirred at 25 °C for 3 h. The reaction was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 90%) to get the title product LD-27d (280 mg, yield: 58%) as a white solid.

[1296] MS m / z (ESI): 750.7 [M+1].

[1297] Third step

[1298] To a solution of LD-27d (280 mg, 0.36 mmol) in methanol (3 mL) and tetrahydrofuran (6 mL) was added 10% palladium on carbon (50 mg) and the resulting mixture was stirred at 25 °C under hydrogen atmosphere at normal pressure for 1 h. The reaction was filtered and the filter cake was washed with methanol (10 mL) and then the filtrate was concentrated under reduced pressure. The concentrated residue was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 80%) to get the title product LD-27e (130 mg, yield: 53%) as a white solid.

[1299] MS m / z (ESI): 658.5 [M-1].

[1300] Fourth step

[1301] LD-27e (110 mg, 0.16 mmol) and 2-(7-azobenzotriazole)-N,N,N',N'- tetramethyluronium hexafluorophosphate (69.77 mg, 0.18 mmol) were dissolved in 4 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (107.83 mg, 0.83 mmol) and the trifluoroacetate salt of 1i-1-1 (96.02 mg, 0.16 mmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by C18 reverse-phase column chromatography (mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 30%-90%), to give the title product LD-27f (165 mg, yield: 87%) as a white solid.

[1302] MS m / z (ESI): 1103.9 [M+1].

[1303] Fifth step

[1304] To a solution of LD-27f (165 mg, 0.14 mmol) in N,N-dimethylacetamide (2 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (21.88 mg, 0.14 mmol) under a nitrogen atmosphere, and the resulting mixture was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-80%), to give the title product LD-27g (55 mg, yield: 42%) as a white solid.

[1305] MS m / z (ESI): 881.7 [M+1].

[1306] Sixth step

[1307] LD-25a (3.50 mg, 18.17 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (7.59 mg, 19.99 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.74 mg, 90.85 pmol) and LD-27g (14.39 mg, 16.35 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-27 (8.40 mg, yield: 43%) in the form of a white solid.

[1308] MS m / z (ESI): 1046.8 [M+1].

[1309] Example 3-28: Preparation of LD-28

[1310] N-(((S)-7-benzyl-17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-2,5,8,11,17-pentaoxo-14-oxo-3,6,9,12- tetraazheptadecyl)-5-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)pentanamide LD-28

[1311] LD-24a (4 mg, 19.28 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (8.06 mg, 21.21 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (12.46 mg, 96.44 pmol) and LD-27g (15.28 mg, 17.36 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-27 (11.31 mg, yield: 54%) in the form of a white solid.

[1312] MS m / z (ESI): 1060.9 [M+1].

[1313] Example 3-29: Preparation of LD-29

[1314] N-(((S)-7-benzyl-17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-2,5,8,11,17-pentaoxo-14-oxo-3,6,9,12-tetraazheptadecyl)-6-(2,5- dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamide LD-29

[1315] LD-23g (4 mg, 18.01 μmol) and 2-(7-azobenzo triazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.53 mg, 19.81 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropyl ethylamine (11.64 mg, 90.05 μmol) and LD-27g (14.26 mg, 16.21 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-29 (7.55 mg, yield: 38%) in the form of a white solid.

[1316] MS m / z (ESI): 1074.9 [M+1].

[1317] Example 3-30: Preparation of LD-30

[1318] (S)-N-(2-(((3-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13- dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin- 1-yl)amino)-3-oxopropoxy)methyl)amino)-2-oxoethyl)-2-(15-(2,5-dioxo-2,5-dihydro-1H- pyrrol-1-yl)-4,7-dioxo-10,13-oxo-3,6-diazapentadecanoylamino)-3-phenylpropanamide LD-30

[1319] LD-12d (5 mg, 18.48 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (7.73 mg, 20.33 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (11.94 mg, 92.41 pmol) and LD-27g (14.64 mg, 16.63 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-30 (4.08 mg, yield: 19%) in the form of a white solid.

[1320] MS m / z (ESI): 1120.9 [M+1].

[1321] Example 3-31: Preparation of LD-31

[1322] (S)-N-(2-(((3-(((1S,9S)-9-(Cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1- yl)amino)-3-oxopropoxy)methyl)amino)-2-oxoethyl)-2-(19-(2,5-dioxo-2,5-dihydro-1H- pyrrol-1-yl)-4,7,17-trioxo-10,13-oxa-3,6,16-triazacyclododecanoylamido)-3- phenylpropanamide LD-31

[1323] LD-31a (3.72 mg, 11.36 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'- tetramethyluronium hexafluorophosphate (4.74 mg, 12.49 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.39 mg, 34.08 μmol) and LD-27g (10 mg, 11.36 μmol) were added successively, and the reaction was stirred at 25°C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-31 (4.11 mg, yield: 29%) as a white solid.

[1324] MS m / z (ESI): 1192.1 [M+1].

[1325] Example 3-32: Preparation of LD-32

[1326] N-((7S,15S)-7-benzyl 17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-15-methyl-2,5,8,11,17-pentaoxo-14-oxa-3,6,9,12- tetraazheptadecyl)-6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamide LD-32

[1327] First step

[1328] To a solution of LD-32a (440 mg, 0.87 mmol, prepared using the method disclosed in patent application “WO2023186015 A1” page 38, Example X2) in N,N-dimethylformamide (10 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (66.64 mg, 0.43 mmol) under nitrogen atmosphere and the resulting mixture was stirred at 25 °C for 1 h. To this was then added 1-hydroxybenzotriazole monohydrate (141.96 mg, 1.05 mmol), LD-23b (461.05 mg, 0.91 mmol) and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (184.62 mg, 0.96 mmol) and the resulting mixture was stirred at 25 °C for 3 h. The reaction was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 90%) to get the title product LD-32b (510 mg, yield: 76%) as a white solid. MS m / z (ESI): 764.4 [M+1].

[1329] Second step

[1330] To a solution of LD-32b (510 mg, 0.66 mmol) in methanol (5 mL) and tetrahydrofuran (5 mL) was added 10% palladium on carbon (80 mg) and the resulting mixture was stirred at 25 °C under hydrogen atmosphere at normal pressure for 1 h. The reaction was filtered and the filter cake was washed with methanol (10 mL) and then the filtrate was concentrated under reduced pressure. The concentrated residue was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 80%) to get the title product LD-32c (163 mg, yield: 36%) as a white solid.

[1331] MS m / z (ESI): 672.5 [M-1].

[1332] Third step

[1333] LD-32c (60 mg, 89.06 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'- tetramethyluronium hexafluorophosphate (40.64 mg, 106.87 μmol) were dissolved in 2 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (34.46 mg, 267.17 μmol) and the trifluoroacetate salt of 1i-1-1 (51.20 mg, 89.06 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by C18 reverse-phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 90%), to give the title product LD-32d (75 mg, yield: 75%) as a white solid.

[1334] MS m / z (ESI): 1117.9 [M+1].

[1335] Fourth step

[1336] To a solution of LD-32d (75 mg, 67.08 μmol) in N,N-dimethylformamide (1 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (5.10 mg, 33.54 μmol) under a nitrogen atmosphere, and the resulting mixture was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 80%), to give the title product LD-32e (23 mg, yield: 38%) as a white solid.

[1337] MS m / z (ESI): 895.8 [M+1].

[1338] Fifth step

[1339] LD-23g (2.36 mg, 11.17 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.10 mg, 13.41 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.32 mg, 33.52 μmol) and LD-32e (10 mg, 11.17 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-32 (6.18 mg, yield: 50%) in the form of a white solid.

[1340] MS m / z (ESI): 1089.0 [M+1].

[1341] Example 3-33: Preparation of LD-33

[1342] (S)-3-(((S)-7-benzyl-23-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3,6,9,12,5- pentaoxo-18,21-dioxa-2,5,8,11,14-pentaazatrityl)oxy)-N-((1S,9S)-9-(cyclopropylmethyl)- 5-fluoro-9-hydroxy-4-methyl-10,13-dioxo 2,3,9,10,13,15-hexahydro-1H,12H- benzo[de]pyrano[3',4':6,7]nidoazino[1,2-b]quinolin-1-yl)butanamide LD-33

[1343] LD-12d (3.45 mg, 13.41 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.95 mg, 15.64 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.32 mg, 33.52 μmol) and LD-32e (10 mg, 11.17 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-33 (5.83 mg, yield: 46%) in the form of a white solid.

[1344] MS m / z (ESI): 1135.0 [M+1].

[1345] Example 3-34: Preparation of LD-34

[1346] (S)-3-(((S)-7-benzyl-27-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3,6,9,12,25- hexa oxo-18,21-dioxo-2,5,8,11,14,24-hexaazahexa dec an- yl)oxy)-N-(1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] midazolo[1,2-b]quinolin-1-yl)butanamide LD-34

[1347] LD-31a (3.66 mg, 11.17 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'- tetramethyluronium hexafluorophosphate (4.66 mg, 12.28 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.32 mg, 33.52 μmol) and LD-32e (10 mg, 11.17 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-34 (3.42 mg, yield: 25%) in the form of a white solid.

[1348] MS m / z (ESI): 1206.0 [M+1].

[1349] Example 3-35: Preparation of LD-35

[1350] (S)-3-(((S)-7-benzyl-16-(1-((2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)methyl)cyclopropyl)- 3,6,9,12,15-penta oxo-25,8,11,14-pentaaza hexadecyl)oxy)-N-(1S,9S)-9-(cyclopropylmethyl)- 5-fluoro-9-hydroxy-4-methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H- benzo[de]pyrano[3',4':6,7]midazolo[1,2-b]quinolin-1-yl)butanamide LD-35

[1351] First step

[1352] To a solution of LD-35a (380 mg, 2.92 mmol, prepared by the method disclosed in patent application “WO 2021164351 A1”, page 41, example 29) in N,N-dimethylformamide (6 mL) was added potassium carbonate (605.35 mg, 4.38 mmol) and benzyl bromide (599.28 mg, 3.50 mmol) under nitrogen atmosphere, and the resulting mixture was stirred at 25 °C for 1 hour. To the reaction was added 30 mL of ethyl acetate and 30 mL of water, shaken to separate the phases, the aqueous phase was separated and extracted again with 30 mL of ethyl acetate, the combined organic phases were washed with 20 mL of saturated brine, then dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (mobile phase: A - petroleum ether, B - ethyl acetate; gradient elution: B%: 10% - 40%), to obtain the title product LD-35b (501 mg, yield: 77%) as a colorless liquid.

[1353] MS m / z (ESI): 221.0 [M+1].

[1354] Second step

[1355] To a solution of LD-35b (501 mg, 2.27 mmol) in N,N-dimethylformamide (12 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (519.40 mg, 3.41 mmol) and diphenyl phosphorazide (938.91 mg, 3.41 mmol) under nitrogen atmosphere, and the resulting mixture was stirred at 90 °C for 16 hours. After cooling the reaction to room temperature, it was slowly poured into 100 mL of water, then extracted with 120 mL of ethyl acetate, the organic phase was washed with 50 mL of saturated brine, then dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (mobile phase: A - petroleum ether, B - ethyl acetate; gradient elution: B%: 0% - 30%), to obtain the title product LD-35c (421 mg, yield: 75%) as a colorless liquid.

[1356] MS m / z (ESI): 218.1 [M+1-28].

[1357] Third step

[1358] To a solution of LD-35c (421 mg, 1.71 mmol) in methanol (10 mL) was added 10% palladium on carbon (80 mg), and the resulting mixture was stirred at 25 °C under an atmosphere of hydrogen gas at normal pressure for 1 hour. The reaction was filtered, and the filter cake was washed with methanol (10 mL), and then the filtrate was concentrated under reduced pressure. The crude title product LD-35d (225 mg) was obtained as a white solid. The product was used directly in the next step without purification.

[1359] MS m / z (ESI): [M+1].

[1360] Fourth Step

[1361] To a solution of LD-35d (225 mg, 1.74 mmol) in acetic acid (6 mL) was added maleic anhydride (187.68 mg, 1.91 mmol) under a nitrogen atmosphere, and the resulting mixture was warmed to 120 °C and stirred for 15 hours. After the reaction was cooled to room temperature, it was concentrated under reduced pressure. The resulting residue was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 50%), to give the title product LD-35e (78 mg, yield: 21%) as a white solid.

[1362] MS m / z (ESI): 210.9 [M-1].

[1363] Fifth Step

[1364] LD-35e (2.34 mg, 11.19 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.10 mg, 13.42 μmol) were dissolved in 1 mL of N,N-dimethylformamide, and then N,N-diisopropylethylamine (4.32 mg, 33.56 μmol) and LD-32e (10 mg, 11.19 μmol) were added sequentially, and the reaction was stirred at 25 °C for 1 hour. The reaction was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 20% - 65%), to give the title product LD-35 (5.08 mg, yield: 41%) as a white solid.

[1365] MS m / z (ESI): 1087.1 [M+1]. 1H NMR (400 MHz, DMSO-d6) δ 8.55 - 8.40 (m, 2H), 8.28 (t, J = 5.8 Hz, 1H), 8.10 (d, J = 8.1 Hz, 1H), 8.03 - 7.91 (m, 2H), 7.80 (d, J = 11.0 Hz, 1H), 7.39 (s, 1H), 7.26 - 7.17 (m, 4H), 7.17 - 7.11 (m, 1H), 7.00 (s, 2H), 6.60 (s, 1H), 5.63 - 5.51 (m, 1H), 5.50 - 5.36 (m, 2H), 5.33 - 5.13 (m, 2H), 4.69 - 4.60 (m, 1H), 4.60 - 4.45 (m, 2H), 4.09 - 3.98 (m, 1H), 3.78 - 3.55 (m, 6H), 3.38 (s, 2H), 3.22 - 3.10 (m, 2H), 3.06 - 2.98 (m, 1H), 2.81 - 2.74 (m, 1H), 2.44 - 2.31 (m, 4H), 2.28 - 2.20 (m, 1H), 2.18 - 2.08 (m, 4H), 1.89 - 1.70 (m, 2H), 1.12 (d, J = 6.1 Hz, 3H), 0.87 - 0.75 (m, 1H), 0.55 - 0.48 (m, 2H), 0.47 - 0.41 (m, 2H), 0.39 - 0.24 (m, 2H), 0.09 - 0.02 (m, 1H), -0.05 - -0.13 (m, 1H).

[1366] Example 3-36: Preparation of LD-36

[1367] N-((7S,15R)-7-benzyl 17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-15-methyl-2,5,8,11,17-pentaoxo-14-oxa-3,6,9,12- tetraazheptadecyl)-6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-4-methylhexanamide LD-36

[1368] First Step

[1369] To a solution of LD-36a (1 g, 8.92 mmol) in dichloromethane (20 mL) was added meta-chloroperoxybenzoic acid (2.17 g, 10.70 mmol, 85%) under nitrogen atmosphere, and the resulting mixture was stirred at 25 °C for 2 hours. The reaction solution was filtered, the filter cake was washed with DCM (5 mL), the combined filtrate was washed with saturated sodium carbonate solution (15 mL) and then with saturated brine (15 mL), the organic phase was separated and dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (mobile phase: A - petroleum ether, B - ethyl acetate; gradient elution: B%: 0% - 30%) to give the title product LD-36b (970 mg, yield: 84%) as a colorless liquid.

[1370] Second Step

[1371] To a solution of sodium hydroxide (580.48 mg, 14.51 mmol) in water (5 mL) was added LD-36b (620 mg, 4.84 mmol), and the resulting mixture was stirred at 25 °C for 1 hour. To the reaction solution was added 6 mol / L aqueous hydrochloric acid solution dropwise, the pH of the reaction solution was adjusted to 2, and then extracted with ethyl acetate (15 mL*3), the combined organic phase was washed with saturated brine (15 mL), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The crude title product LD-36c (533 mg) was obtained as a colorless liquid. The product was used directly in the next step without purification.

[1372] MS m / z (ESI): 144.9 [M-1].

[1373] Third Step

[1374] To a solution of LD-36c (400 mg, 3.12 mmol) in N,N-dimethylformamide (5 mL) was added potassium carbonate (674.00 mg, 4.68 mmol) and benzyl bromide (640.51 mg, 4.68 mmol) successively under nitrogen atmosphere, and the resulting mixture was stirred at 25 °C for 1 hour. To the reaction solution was added 30 mL of ethyl acetate and 30 mL of water, shaken and separated, the aqueous phase was extracted with 30 mL of ethyl acetate, the combined organic phase was washed with 20 mL of saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (mobile phase: A - petroleum ether, B - ethyl acetate; gradient elution: B%: 10% - 40%) to give the title product LD-36d (595 mg, yield: 76%) as a colorless liquid.

[1375] MS m / z (ESI): 237.1 [M+1].

[1376] Fourth Step

[1377] To a solution of LD-36d (268 mg, 1.13 mmol) in N,N-dimethylformamide (6 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (258.98 mg, 1.70 mmol) and diphenyl phosphorazide (468.16 mg, 1.70 mmol) successively under nitrogen atmosphere and the resulting mixture was warmed to 90 °C for stirring for 16 hours. After the reaction was cooled to room temperature, it was slowly poured into 50 mL of water and extracted with 80 mL of ethyl acetate, and the organic phase was washed with 50 mL of saturated brine, then dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (mobile phase: A-petroleum ether, B-ethyl acetate; gradient elution: B%: 0%-30%) to give the title product LD-36e (223 mg, yield: 75%) as a colorless liquid.

[1378] MS m / z (ESI): 234.1 [M+1-28]

[1379] Fifth step

[1380] To a solution of LD-36e (223 mg, 0.36 mmol) in methanol (6 mL) was added 10% palladium-carbon (40 mg) and the resulting mixture was stirred under hydrogen atmosphere at 25 °C for 1 hour. The reaction was filtered, and the filter cake was washed with methanol (10 mL), and then the filtrate was concentrated under reduced pressure. The crude title product LD-36f (155 mg) was obtained as a white solid. The product was used directly in the next step without purification.

[1381] MS m / z (ESI): 145.9 [M+1].

[1382] Sixth step

[1383] To a solution of LD-36f (155 mg, 1.07 mmol) in acetic acid (5 mL) was added maleic anhydride (115.15 mg, 1.17 mmol) under nitrogen atmosphere and the resulting mixture was stirred at 120 °C for 15 hours. After the reaction was cooled to room temperature, it was concentrated under reduced pressure. The resulting residue was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 µm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 10%-50%) to give the title product LD-36g (49 mg, yield: 19%) as a white solid.

[1384] MS m / z (ESI): 224.0 [M-1].

[1385] Seventh step

[1386] LD-36g (2.77 mg, 11.19 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.10 mg, 13.42 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.32 mg, 33.56 pmol) and LD-23f (10 mg, 11.19 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-36 (4.66 mg, yield: 37%) in the form of a white solid.

[1387] MS m / z (ESI): 1103.0 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.55 - 8.40 (m, 2H), 8.29 (t, J = 5.9 Hz, 1H), 8.17 - 8.04 (m, 2H), 8.01 (t, J = 5.7 Hz, 1H), 7.79 (d, J = 10.9 Hz, 1H), 7.37 (s, 1H), 7.30 - 7.12 (m, 5H), 6.99 (s, 2H), 6.58 (s, 1H), 5.61 - 5.51 (m, 1H), 5.49 - 5.34 (m, 2H), 5.30 - 5.11 (m, 2H), 4.63 - 4.42 (m, 3H), 4.07 - 3.95 (m, 1H), 3.79 - 3.54 (m, 6H), 3.38 (t, J = 7.3 Hz, 2H), 3.23 - 3.11 (m, 2H), 3.07 - 2.99 (m, 1H), 2.84 - 2.70 (m, 1H), 2.48 - 2.33 (m, 4H), 2.28 - 2.19 (m, 1H), 2.18 - 2.01 (m, 4H), 1.88 - 1.71 (m, 2H), 1.57 - 1.42 (m, 2H), 1.39 - 1.21 (m, 3H), 1.14 (d, J = 6.1 Hz, 3H), 0.92 - 0.75 (m, 4H), 0.41 - 0.24 (m, 2H), 0.11 - 0.02 (m, 1H), -0.03 - -0.13 (m, 1H).

[1388] Example 3-37: Preparation of LD-37

[1389] N-((S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10, 13-dioxo-2,3,9,10, 13, 15-hexahydro-lH, 12H-benzo[de]pyrano[3',4':6,7] indolizino[l,2-b]quinolin-l-yl)amino)-l,6,9, 12, 15-pentaoxo-3-oxa-5,8, 11, 14- tetraazahexadec-16-yl)-6-(2,5-dioxo-2,5-dihydro-lH-pyrrol-l-yl)-4-methylhexanamide LD-37

[1390] LD-36g (3 mg, 13.32 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.57 mg, 14.65 μmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (6.89 mg, 53.28 μmol) and LD-12b (10.39 mg, 11.99 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-37 (6.11 mg, yield: 42%) as a white solid.

[1391] MS m / z (ESI): 1075.0 [M+1]. 1H NMR (400 MHz, DMSO-d6) δ 8.62 (t, J = 6.7 Hz, 1H), 8.51 (d, J = 8.9 Hz, 1H), 8.30 (t, J = 5.9 Hz, 1H), 8.12 (d, J = 7.9 Hz, 1H), 8.07 (t, J = 5.7 Hz, 1H), 8.00 (t, J = 5.7 Hz, 1H), 7.77 (d, J = 10.9 Hz, 1H), 7.37 (s, 1H), 7.30 - 7.11 (m, 5H), 6.99 (s, 2H), 6.58 (s, 1H), 5.65 - 5.53 (m, 1H), 5.49 - 5.33 (m, 2H), 5.27 - 5.13 (m, 2H), 4.64 (d, J = 6.6 Hz, 2H), 4.53 - 4.37 (m, 1H), 4.02 (s, 2H), 3.79 - 3.51 (m, 6H), 3.38 (t, J = 7.3 Hz, 2H), 3.26 - 3.08 (m, 2H), 3.07 - 2.96 (m, 1H), 2.82 - 2.73 (m, 1H), 2.38 (d, J = 1.8 Hz, 3H), 2.26 - 2.01 (m, 4H), 1.88 - 1.69 (m, 2H), 1.56 - 1.43 (m, 2H), 1.38 - 1.18 (m, 3H), 0.93 - 0.73 (m, 4H), 0.41 - 0.23 (m, 2H), 0.10 - 0.02 (m, 1H), -0.03 - -0.14 (m, 1H).

[1392] Example 3-38: Preparation of LD-38

[1393] (S)-N-(2-((((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo- 2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2-b]quinolin-1- yl)amino)-2-oxoethoxy)methyl)amino)2-oxoethyl)-2-(2-(2-(1-((2,5-dioxo-2,5-dihydro-1H- pyrrol-1-yl)methyl)amido)ethyl)phenoxy)acetamide LD-38

[1394] LD-35e (3 mg, 14.34 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (6.54 mg, 17.21 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (7.41 mg, 57.36 pmol) and LD-12b (11.19 mg, 12.91 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-38 (2.55 mg, yield: 16%) in the form of a white solid.

[1395] MS m / z (ESI): 1058.9 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.62 (t, J = 6.7 Hz, 1H), 8.51 (d, J = 8.9 Hz, 1H), 8.29 (t, J = 5.8 Hz, 1H), 8.12 (d, J = 8.0 Hz, 1H), 8.05 - 7.90 (m, 2H), 7.78 (d, J = 10.9 Hz, 1H), 7.37 (s, 1H), 7.30 - 7.08 (m, 5H), 6.99 (s, 2H), 6.59 (s, 1H), 5.65 - 5.56 (m, 1H), 5.48 - 5.33 (m, 2H), 5.28 - 5.15 (m, 2H), 4.64 (d, J = 6.5 Hz, 2H), 4.50 - 4.42 (m, 1H), 4.02 (s, 2H), 3.79 - 3.54 (m, 6H), 3.37 (s, 2H), 3.20 - 3.15 (m, 1H), 3.06 - 2.97 (m, 1H), 2.83 - 2.74 (m, 1H), 2.71 - 2.64 (m, 1H), 2.38 (d, J = 1.9 Hz, 3H), 2.35 - 2.30 (m, 1H), 2.22 - 2.13 (m, 3H), 1.87 - 1.70 (m, 2H), 0.87 - 0.75 (m, 1H), 0.55 - 0.47 (m, 2H), 0.47 - 0.39 (m, 2H), 0.39 - 0.24 (m, 2H), 0.11 - -0.00 (m, 1H), -0.03 - -0.14 (m, 1H).

[1396] Example 3-39: Preparation of LD-39

[1397] N-((17S,25R)-17-benzyl-27-((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10, 13-dioxo-2, 3, 9, 10, 13, 15-hexahydro-1H, 12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-25-methyl-9, 12, 15, 18, 21, 27-hexaoxo-3, 6, 24- trioxa-10, 13, 16, 19, 22-pentaazahexan-1-yl)-1-((2, 5-dioxo-2, 5-dihydro-1H-pyrrol-1- yl)methyl)cyclopropane-1-carboxamide LD-39

[1398] First Step

[1399] To a solution of LD-39a (1 g, 9.00 mmol) in methanol (20 mL) was added platinum dioxide (200 mg) and concentrated hydrochloric acid (0.7 mL) under nitrogen atmosphere and the resulting mixture was stirred at 25 °C under hydrogen gas atmosphere at normal pressure for 4 hours. The reaction was filtered and the filter cake was washed with methanol (20 mL), then the filtrate was concentrated under reduced pressure. The crude product of the title compound, hydrochloride salt of LD-39b was obtained as a yellow oil (1.35 g). The product was used directly in the next step without purification.

[1400] MS m / z (ESI): 115.9 [M+1].

[1401] Second Step

[1402] To a solution of the hydrochloride salt of LD-39b (1.35 g, 8.91 mmol) in acetic acid (20 mL) was added maleic anhydride (0.96 g, 9.80 mmol) under nitrogen atmosphere and the resulting mixture was warmed to 120 °C and stirred for 15 hours. The reaction was cooled to room temperature and concentrated under reduced pressure. The resulting residue was purified by C18 reverse phase column chromatography (mobile phase: A - water (0.1% formic acid), B - acetonitrile; gradient elution: B%: 10% - 50%) to obtain the title product, LD-39c (220 mg, yield: 12%) as a white solid.

[1403] MS m / z (ESI): 193.9 [M-1].

[1404] Third Step

[1405] LD-39c (220 mg, 1.13 mmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (514.34 mg, 1.35 mmol) were dissolved in 6 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (582.73 mg, 4.51 mmol) and LD-39d (262.99 mg, 1.13 mmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by C18 reverse phase column chromatography (mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-80%), to obtain the title product LD-39e (253 mg, yield: 54%) in the form of a white solid.

[1406] MS m / z (ESI): 355.2 [M+1-56].

[1407] Fourth step

[1408] To a solution of LD-39e (253 mg, 0.61 mmol) in dichloromethane (3 mL) was added trifluoroacetic acid (3 mL), and the resulting mixture was stirred at 25 °C for 1 hour. The reaction solution was concentrated under reduced pressure. The resulting residue was purified by C18 reverse phase column chromatography (mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 5%-60%), to obtain the title product LD-39f (145 mg, yield: 88%) in the form of a white solid.

[1409] MS m / z (ESI): 353.2 [M-1].

[1410] Fifth step

[1411] LD-39f (4 mg, 11.29 μmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (4.72 mg, 12.42 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (3.64 mg, 28.22 μmol) and LD-23f (9.09 mg, 10.16 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-39 (5.51 mg, yield: 44%) in the form of a white solid.

[1412] MS m / z (ESI): 1232.1 [M+1]. 1H NMR (400 MHz, DMSO-d6) δ 8.55 - 8.42 (m, 2H), 8.29 (t, J = 5.8 Hz, 1H), 8.22 - 8.06 (m, 2H), 8.01 (t, J = 5.7 Hz, 1H), 7.79 (d, J = 10.9 Hz, 1H), 7.59 (t, J = 5.5 Hz, 1H), 7.37 (s, 1H), 7.29 - 7.12 (m, 5H), 7.02 (s, 2H), 6.58 (s, 1H), 5.61 - 5.51 (m, 1H), 5.48 - 5.35 (m, 2H), 5.34 - 5.13 (m, 2H), 4.64 - 4.42 (m, 3H), 4.07 - 3.96 (m, 1H), 3.83 - 3.53 (m, 10H), 3.45 (s, 4H), 3.38 - 3.33 (m, 2H), 3.21 - 3.09 (m, 4H), 3.08 - 3.00 (m, 1H), 2.84 - 2.74 (m, 1H), 2.48 - 2.32 (m, 6H), 2.29 - 2.19 (m, 1H), 2.19 - 2.06 (m, 2H), 1.89 - 1.70 (m, 2H), 1.14 (d, J = 6.1 Hz, 3H), 0.94 - 0.87 (m, 2H), 0.86 - 0.71 (m, 3H), 0.40 - 0.25 (m, 2H), 0.10 - 0.02 (m, 1H), -0.04 - -0.14 (m, 1H).

[1413] Example 3-40: Preparation of LD-40

[1414] N-((17S,25S)-17-benzyl-27-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-25-methyl-9,12,15,18,21,27-hexaoxo-3,6,24- trioxa-10,13,16,19,22-pentaazheptanyl)-1-((2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)methyl)cyclopropane-1-carboxamide LD-40

[1415] LD-39f (4 mg, 11.29 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (4.72 mg, 12.42 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (3.64 mg, 28.22 pmol) and LD-32e (9.09 mg, 10.16 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-40 (5.23 mg, yield: 41%) in the form of a white solid.

[1416] MS m / z (ESI): 1232.1 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.57 - 8.42 (m, 2H), 8.28 (t, J = 5.8 Hz, 1H), 8.22 - 8.05 (m, 2H), 7.99 (t, J = 5.7 Hz, 1H), 7.80 (d, J = 10.9 Hz, 1H), 7.59 (t, J = 5.6 Hz, 1H), 7.39 (s, 1H), 7.30 - 7.07 (m, 5H), 7.02 (s, 2H), 6.60 (s, 1H), 5.64 - 5.52 (m, 1H), 5.49 - 5.34 (m, 2H), 5.33 - 5.13 (m, 2H), 4.69 - 4.60 (m, 1H), 4.60 - 4.44 (m, 2H), 4.10 - 3.98 (m, 1H), 3.79 - 3.53 (m, 9H), 3.45 (s, 4H), 3.39 - 3.35 (m, 3H), 3.21 - 3.09 (m, 4H), 3.06 - 2.97 (m, 1H), 2.82 - 2.71 (m, 1H), 2.44 - 2.30 (m, 6H), 2.29 - 2.20 (m, 1H), 2.17 - 1.70 (m, 8H), 1.12 (d, J = 6.1 Hz, 3H), 0.94 - 0.86 (m, 2H), 0.86 - 0.70 (m, 3H), 0.40 - 0.24 (m, 2H), 0.10 - 0.01 (m, 1H), -0.04 - -0.13 (m, 1H).

[1417] 2.05 (m, 2H), 1.88 - 1.70 (m, 2H), 1.12 (d, J = 6.1 Hz, 3H), 0.94 - 0.86 (m, 2H), 0.86 - 0.70 (m, 3H), 0.40 - 0.24 (m, 2H), 0.10 - 0.01 (m, 1H), -0.04 - -0.13 (m, 1H).

[1418] Example 3-41: Preparation of LD-41

[1419] N-((7S,15S)-7-benzyl 17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4- methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7] indolizino[1,2-b]quinolin-1-yl)amino)-15-methyl-2,5,8,11,17-pentaoxo-14-oxa- 3,6,9,12-tetraazheptadecyl)-6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-4-methylhexanamide LD-41

[1420] LD-36g (2.77 mg, 11.19 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.10 mg, 13.42 μmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (4.32 mg, 33.56 μmol) and LD-32e (10 mg, 11.19 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-41 (6.71 mg, yield: 54%) in the form of a white solid.

[1421] MS m / z (ESI): 1103.0 [M+1]. 1H NMR (400 MHz, DMSO-d6) δ 8.48 (d, J = 8.0 Hz, 2H), 8.28 (t, J = 5.8 Hz, 1H), 8.15 - 8.05 (m, 2H), 7.99 (t, J = 5.7 Hz, 1H), 7.80 (d, J = 11.0 Hz, 1H), 7.39 (s, 1H), 7.30 - 7.08 (m, 5H), 6.99 (s, 2H), 6.60 (s, 1H), 5.63 - 5.52 (m, 1H), 5.50 - 5.35 (m, 2H), 5.34 - 5.14 (m, 2H), 4.70 - 4.60 (m, 1H), 4.60 - 4.45 (m, 2H), 4.09 - 3.98 (m, 1H), 3.79 - 3.52 (m, 6H), 3.43 - 3.35 (m, 2H), 3.23 - 3.10 (m, 2H), 3.07 - 2.98 (m, 1H), 2.83 - 2.70 (m, 1H), 2.45 - 2.30 (m, 4H), 2.29 - 2.19 (m, 1H), 2.18 - 2.03 (m, 4H), 1.88 - 1.71 (m, 2H), 1.58 - 1.44 (m, 2H), 1.38 - 1.20 (m, 3H), 1.12 (d, J = 6.1 Hz, 3H), 0.92 - 0.74 (m, 4H), 0.40 - 0.23 (m, 2H), 0.09 - 0.01 (m, 1H), -0.04 - -0.15 (m, 1H).

[1422] Example 3-42: Preparation of LD-42

[1423] (R)-3-(((S)-7-benzyl-16-(1-((2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)methyl)cyclopropyl)-3,6,9,12,15-pentaoxo-25,8,11,14-pentaazahexadecyl)oxy)-N-(1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl-10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]nidoazino[1,2-b]quinolin-1-yl)butanamide LD-42

[1424] LD-35e (2.34 mg, 11.19 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate (5.10 mg, 13.42 μmol) were dissolved in 1 mL of N,N-dimethylformamide, followed by the sequential addition of N,N-diisopropylethylamine (4.32 mg, 33.56 μmol) and LD-23f (10 mg, 11.19 μmol). The mixture was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120SB-C18 21.2 × 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), yielding the title product LD-42 (5.45 mg, yield: 43%) as a white solid.

[1425] MS m / z(ESI):1087.0[M+1]. 1 H NMR (400MHz, DMSO-d6) δ8.54–8.43(m,2H),8.29(t,J=5.8Hz,1H),8.12(d,J=8.0Hz,1H),8.05–7.91(m,2H),7.79(d,J=10.9Hz,1H),7.37(s,1H),7. 32–7.08(m,5H),7.00(s,2H),6.58(s,1H),5.63–5.48(m,1H),5.48–5.33( m,2H),5.29–5.10(m,2H),4.65–4.38(m,3H),4.10–3.91(m,1H),3.85–3.5 1(m,6H),3.38(s,2H),3.23–3.10(m,2H),3.09–2.99(m,1H),2.85–2.74(m ,1H),2.48–2.35(m,4H),2.29–2.19(m,1H),2.19–2.06(m,4H),1.89–1.69 (m,2H),1.14(d,J=6.1Hz,3H),0.88–0.73(m,1H),0.55–0.47(m,2H),0.47 –0.41(m,2H),0.40–0.25(m,2H),0.11–0.02(m,1H),-0.04–-0.13(m,1H).

[1426] Examples 3-43: Preparation of LD-43

[1427] N-(((S)-7-benzyl-17-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-2,5,8,11,17-pentaoxo-14-oxa-3,6,9,12-tetraazheptadecyl)-6-(2,5-dioxo- 2,5-dihydro-1H-pyrrol-1-yl)-4-methylhexanamide LD-43

[1428] LD-36g (3 mg, 13.20 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.02 mg, 13.20 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.26 mg, 33.00 μmol) and LD-27g (10.45 mg, 11.88 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-43 (4.08 mg, yield: 27%) in the form of a white solid.

[1429] MS m / z (ESI): 1089.0 [M+1]. 1H NMR (400 MHz, DMSO-d6) δ 8.57 - 8.43 (m, 2H), 8.29 (t, J=5.8 Hz, 1H), 8.17 - 8.05 (m, 2H), 8.01 (t, J=5.7 Hz, 1H), 7.80 (d, J=11.0 Hz, 1H), 7.38 (s, 1H), 7.31 - 7.10 (m, 5H), 6.99 (s, 2H), 6.59 (s, 1H), 5.61 - 5.51 (m, 1H), 5.51 - 5.34 (m, 2H), 5.30 - 5.15 (m, 2H), 4.62 - 4.41 (m, 3H), 3.89 - 3.46 (m, 8H), 3.38 (t, J=7.3 Hz, 2H), 3.22 - 3.11 (m, 2H), 3.07 - 2.98 (m, 1H), 2.84 - 2.73 (m, 1H), 2.44 - 2.32 (m, 5H), 2.19 - 2.02 (m, 4H), 1.88 - 1.70 (m, 2H), 1.59 - 1.43 (m, 2H), 1.39 - 1.20 (m, 3H), 0.92 - 0.74 (m, 4H), 0.40 - 0.23 (m, 2H), 0.10 - 0.02 (m, 1H), -0.04 - -0.14 (m, 1H).

[1430] Example 3-44: Preparation of LD-44

[1431] (S)-N-(2-(((3-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-3-oxopropoxy)methyl)amino)-2-oxoethyl)-2-(2-(2-(1-(((2,5-dioxo- 2,5-dihydro-1H-pyrrol-1-yl)methyl)amino)ethyl)phenoxy)ethoxy)acetamide LD-44

[1432] LD-35e (3 mg, 14.21 μmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.40 mg, 14.21 μmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (4.59 mg, 35.53 μmol) and LD-27g (11.25 mg, 12.79 μmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell120 SB-C18 21.2 x 150 mm, 4 μm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-44 (4.33 mg, yield: 27%) in the form of a white solid.

[1433] MS m / z (ESI): 1072.9 [M+1]. 1 H NMR (400 MHz, DMSO-d6) δ 8.59 - 8.40 (m, 2H), 8.29 (t, J = 5.8 Hz, 1H), 8.12 (d, J = 8.0 Hz, 1H), 8.06 - 7.92 (m, 2H), 7.80 (d, J = 11.0 Hz, 1H), 7.38 (s, 1H), 7.34 - 7.07 (m, 5H), 7.00 (s, 2H), 6.59 (s, 1H), 5.63 - 5.50 (m, 1H), 5.50 - 5.33 (m, 2H), 5.22 (s, 2H), 4.69 - 4.39 (m, 3H), 3.95 - 3.51 (m, 8H), 3.38 (s, 2H), 3.22 - 3.10 (m, 2H), 3.07 - 2.98 (m, 1H), 2.86 - 2.72 (m, 1H), 2.45 - 2.27 (m, 5H), 2.24 - 2.00 (m, 4H), 1.89 - 1.69 (m, 2H), 0.89 - 0.74 (m, 1H), 0.65 - 0.40 (m, 4H), 0.40 - 0.24 (m, 2H), 0.11 - 0.02 (m, 1H), -0.03 - -0.13 (m, 1H).

[1434] Example 3-45: Preparation of LD-45

[1435] N-((S)-17-benzyl-27-(((1S,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10,13-dioxo-2,3,9,10,13,15-hexahydro-1H,12H-benzo[de]pyrano[3',4':6,7]indolizino[1,2- b]quinolin-1-yl)amino)-9,12,15,18,21,27-hexaoxo-3,6,24-trioxa-10,13,16,19,22- pentaazahexaenyl)-1-((2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)methyl)cyclopropane-1- carboxamide LD-45

[1436] First step

[1437] LD-39f (5 mg, 13.98 pmol) and 2-(7-azobenzotriazol)-N,N,N',N'-tetramethyluronium hexafluorophosphate (5.31 mg, 13.98 pmol) were dissolved in 1 mL of N,N- dimethylformamide, then N,N-diisopropylethylamine (4.51 mg, 34.96 pmol) and LD-27g (11.07 mg, 12.58 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-45 (5.12 mg, yield: 29%) in the form of a white solid.

[1438] MS m / z (ESI): 1218.0 [M+1]. 1H NMR (400 MHz, DMSO-d6) δ 8.58 - 8.44 (m, 2H), 8.29 (t, J = 5.9 Hz, 1H), 8.21 - 8.07 (m, 2H), 8.01 (t, J = 5.7 Hz, 1H), 7.80 (d, J = 10.9 Hz, 1H), 7.59 (t, J = 5.5 Hz, 1H), 7.38 (s, 1H), 7.33 - 7.07 (m, 5H), 7.02 (s, 2H), 6.59 (s, 1H), 5.63 - 5.50 (m, 1H), 5.50 - 5.32 (m, 2H), 5.22 (s, 2H), 4.66 - 4.42 (m, 3H), 3.82 - 3.52 (m, 10H), 3.45 (s, 3H), 3.37 - 3.35 (m, 2H), 3.31 (s, 4H), 3.22 - 3.10 (m, 4H), 3.07 - 2.97 (m, 1H), 2.83 - 2.74 (m, 1H), 2.44 - 2.29 (m, 6H), 2.19 - 2.05 (m, 2H), 1.90 - 1.67 (m, 2H), 0.94 - 0.86 (m, 2H), 0.86 - 0.70 (m, 3H), 0.41 - 0.23 (m, 2H), 0.11 - 0.00 (m, 1H), -0.03 - -0.14 (m, 1H).

[1439] Example 3-46: Preparation of LD-46

[1440] N-((S)-10-benzyl-l-(((lS,9S)-9-(cyclopropylmethyl)-5-fluoro-9-hydroxy-4-methyl- 10, 13-dioxo-2, 3, 9, 10, 13, 15-hexahydro-lH, 12H-benzo[de]pyrano[3',4':6,7]indolizino[l,2-b]quinolin-l- yl)amino)-l,6,9,12,15,18-hexaoxo-3,21,24-trioxa-5,8,11,14,17-pentaazahexacosan-26-yl)-l-((2,5-dioxo- 2,5-dihydro-lH-pyrrol-l-yl)methyl)cyclopropane-l-carboxamide LD-46

[1441] LD-39f (4.50 mg, 12.70 pmol) and 2-(7-azobenzotriazole)-N,N,N',N'- tetramethyluronium hexafluorophosphate (5.31 mg, 13.97 pmol) were dissolved in 1 mL of N,N-dimethylformamide, then N,N-diisopropylethylamine (2.46 mg, 19.05 pmol) and LD-12b (9.91 mg, 11.43 pmol) were added successively, and the reaction was stirred at 25 °C for 1 hour. The reaction solution was purified by pre-HPLC (column: InfinityLab Poroshell 120 SB-C18 21.2 x 150 mm, 4 pm; mobile phase: A-water (0.1% formic acid), B-acetonitrile; gradient elution: B%: 20%-65%), to obtain the title product LD-46 (4.96 mg, yield: 31%) in the form of a white solid.

[1442] MS m / z (ESI): 1204.1 [M+1]. 1 H NMR (400 MHz, DMSO-d6) d 8.63 (t, J = 6.7 Hz, 1H), 8.52 (d, J = 8.9 Hz, 1H), 8.30 (t, J = 5.9 H...

Claims

1. A compound of Formula (D), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof: wherein * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; A1is selected from -C 0-6 alkylene-OH, -C 0-6 alkylene-NH2or -C 0-6 alkylene-SH; A2is selected from -(CR a R b ) k - or -(CR a R b ) k - O-(CR a R b ) k - ; R a and R b are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; or two R groups on different carbon atoms a 3-10 cycloalkylene, 3-10 membered heterocyclyl ene, C 6-10 arylene or 5-10 membered heteroarylene;​ k is 2, 3, 4, 5, or 6; A3is selected from -C 0-6 alkylene-NH-C 0-6 alkylene-, -C 0-6 alkylene-C(O)-C 0-6 alkylene-, -C 0-6 alkylene-NHC(O)-C 0-6 alkylene-, -C 0-6 alkylene-C(O)NH-C 0-6 alkylene-, -C 0-6 alkylene-NHC(O)O-C 0-6 alkylene- or -C 0-6 alkylene-NHC(O)NH-C 0-6 alkylene-; A1, A2and A3are optionally substituted with 1, 2, 3, 4 or 5 R A substituted, as chemically allowed; R1and R2are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-10 cycloalkyl, 5-10 membered heterocyclyl, C 6-10 aryl or 5-10 membered heteroaryl; R1, R2, and the ring formed by R1and R2are optionally substituted with 1, 2, 3, 4, or 5 R B substituted; R3and R4are independently selected from H, halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; or R3and R4are linked to form, together with the carbon atom to which they are attached, a C 4-10 cycloalkyl, 4-10 membered heterocyclyl, C 6-10 aryl or 5-10 membered heteroaryl; R3, R4, and the ring formed by R3and R4are optionally substituted with 1, 2, 3, 4, or 5 R C substituted; R5is selected from -NH2or -OH, preferably OH; R6is selected from C 3-10 cycloalkyl, 3-10 membered heterocyclyl, C 6-10 aryl, 5-10 membered heteroaryl, -C 1-6 alkylene-C 3-10 cycloalkyl, -C 1-6 alkylene-3-10 membered heterocyclyl, -C 1-6 alkylene-C 6-10 aryl or -C 1-6 alkylene-5-10 membered heteroaryl, preferably -C 1-6 alkylene-C 3-10 cycloalkyl; R6is optionally substituted with 1, 2, 3, 4, or 5 R D substituted; each R A , R B , R C , and R D is independently selected from deuterium, halogen, -C 0-6 alkylene-OH, -C 0-6 alkylene-CN, -C 0-6 alkylene-NH2, C 1-6 alkyl, -C 0-6 alkylene-C 1-6 alkoxy, -C 0-6 alkylene-C 1-6 haloalkyl, -C 0-6 alkylene-C 1-6 haloalkoxy, -C 0-6 alkylene-C 3-10 cycloalkyl, -C 0-6 alkylene-3-10 membered heterocyclyl, -C 0-6 alkylene-C 6-10 aryl, or -C 0-6 alkylene-5-10 membered heteroaryl.

2. The compound of claim 1, wherein * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; A1is selected from -OH, -CH2OH, -NH2, -CH2NH2, -SH, or -CH2SH; A2is -(CR a R b ) k -; R a and R b are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl, preferably H or C 1-6 alkyl; or two R groups on different carbon atoms a 3-7 cycloalkylene or 3-7 membered heterocyclylene;​ k is 2, 3, or 4; A3is selected from -NH-, -C(O)-, -NHC(O)-, or -C(O)NH-; A1-A2-A3- optionally further substituted by 1, 2 or 3 substituents selected from the group consisting of halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, C 1-6 haloalkoxy; R1and R2are independently selected from H, C 1-6 alkyl, C 1-6 haloalkyl, C 1-6 alkoxy or C 1-6 haloalkoxy; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl or 5-7 membered heterocyclyl; R3and R4are independently selected from halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; or R3and R4are linked together with the carbon atom to which both are attached to form C 4-10 cycloalkyl or 4-10 membered heterocyclyl; R5is OH; R6is selected from -C 1-6 alkylene-C 3-7 cycloalkyl or -C 1-6 alkylene-3-7 membered heterocyclyl.

3. The compound of claim 1 or 2, wherein * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; A1-A2-A3- is selected from A1-A2-A3- optionally further substituted by 1, 2 or 3 substituents selected from the group consisting of halogen, CN, OH, NH2, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl, C 1-6 haloalkoxy; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5is OH; R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl.

4. The compound of any one of claims 1-3, wherein, The compounds have the structure of Formula (D-1), Formula (D-2), Formula (D-3), or Formula (D-4): wherein *1, *2, *3are chiral centers independently selected from the (S) or (R) absolute configuration, or a mixture thereof; Ring A is selected from C 3-10 cycloalkylene, 3-10 membered heterocyclyl, C 6-10 arylene or 5-10 membered heteroarylene; Ring B is selected from C 3-10 cycloalkyl, 3-10 membered heterocyclyl, C 6-10 aryl or 5-10 membered heteroaryl; each of the other variables is as defined in any one of claims 1-3; Preferably, *2is in the (R) absolute configuration.

5. The compound of any one of claims 1-4, wherein, The compounds have the structure of formula (D-1) or formula (D-2): wherein *1is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; *2is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; *3is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; A1is selected from -OH, -CH2OH, -NH2, -CH2NH2, -SH, or -CH2SH, preferably -OH or -CH2OH; R a and R b are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl; R4is selected from halogen, OH or C 1-6 alkyl; or R3and R4are linked together with the carbon atom to which they are attached to form a C 3-7 cycloalkyl or 3-7 membered heterocyclyl; Ring B is selected from C 3-7 cycloalkyl or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkyl; Preferably, in formula (D-2), R a and R b are preferably not simultaneously H; Preferably, R b is preferably H; More preferably, *1is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; *2is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof, preferably in the (R) absolute configuration; *3is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof, preferably in the (S) absolute configuration; A1is selected from -OH, -CH2OH, -NH2, or -CH2NH2, preferably -OH or -CH2OH; R a is selected from H or C 1-4 alkyl, for example H or methyl; when R a *1 is preferably in the (S) or (R) configuration and *2 is preferably in the (R) absolute configuration when R R b independently selected from H or C 1-4 alkyl, for example H or methyl, preferably H; In formula (D-2), R a and R b are preferably not simultaneously H; R3is C 1-6 alkyl, preferably C 1-4 alkyl, for example methyl; R4is halogen, preferably F; Ring B is C 3-7 cycloalkyl, preferably C 3-5 cycloalkyl, for example cyclopropyl.

6. The compound of any one of claims 1-5, wherein, The compounds have the structure of formula (D-3) or formula (D-4): wherein *1is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; A1is selected from -OH, -CH2OH, -NH2, -CH2NH2, -SH, or -CH2SH, preferably -OH or -CH2OH; Ring A is selected from C 3-7 cycloalkylene or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkylene; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl; R4is selected from halogen, OH or C 1-6 alkyl; or R3and R4are linked together with the carbon atom to which they are attached to form a C 3-7 cycloalkyl or 3-7 membered heterocyclyl; Ring B is selected from C 3-7 cycloalkyl or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkyl; Preferably, *1is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; A1is selected from -OH, -CH2OH, -NH2, or -CH2NH2, preferably -OH; A is C 3-7 cycloalkylene, preferably C 3-5 cycloalkylene, such as cyclobutylene; R3is C 1-6 alkyl, preferably C 1-4 alkyl, for example methyl; R4is halogen, preferably F; Ring B is C 3-7 cycloalkyl, preferably C 3-5 cycloalkyl, for example cyclopropyl.

7. The compound of claim 1, selected from the following compounds, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or mixtures thereof:

8. A linker-drug conjugate selected from a compound of Formula (LD), or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof: L1— L2— L3— D (LD) wherein D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity; L1 is L 1a -L 1b -L 1c -L 1d -L 1e -; L 1a is a thiol reactive group, for example L 1b selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; any 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced by a heteroatom selected from O, S, N, and each -CH2- in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted by 1 or 2 R 1a ; each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d Selected from chemical bonds, C 1-10 Alkylene, C 2-10 imide or C 2-10 Idemyne ​​group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2- 10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1c replace; each R 1c is independently selected from H, halo, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c groups on any identical or different carbon atom can be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl; n is selected from 1, 2, 3, 4, 5, 6, 7, or 8; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine; L3is an optional substituted or unsubstituted spacer.

9. The linker-drug conjugate of claim 8, wherein, D is derived from a compound of formula (D) as defined in any one of claims 1 to 7, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; Preferably, D is a compound of Formula (D’), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof: wherein, A1' is selected from -O-C 0-6 alkylene-, -NH-C 0-6 alkylene- or -S-C 0-6 alkylene-; each variable is as defined in any one of claims 1 to 6.

10. The linker-drug conjugate of claim 8 or 9, wherein, L 1b or L 1d in C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally replaced by a heteroatom of O, S, N at any 1, 2 or 3 non-adjacent carbon atoms.

11. The linker-drug conjugate of any one of claims 8-10, wherein, two R on any identical or different carbon atom 1a together with the carbon atom to which they are attached form a C 3-10 cycloalkyl or 3-10 membered heterocyclyl.

12. The linker-drug conjugate of any one of claims 8-11, wherein, L 1b hydrophilic group substituted, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene.

13. The linker-drug conjugate of any one of claims 8 to 12, wherein: L1is L 1a -L 1b -L 1c -L 1d -L 1e -; L 1a for L 1b selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; each -CH2- in said alkylene, C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1a ; each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, wherein any 1, 2, or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene are optionally replaced with a heteroatom of O, S, N, while, C 1-10 alkylene, C 2- 10 alkenylene, or C 2-10 alkynylene, each -CH2- is optionally substituted with 1 or 2 R 1c ; each R is independently selected from H, halogen, C 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine, preferably L2is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a independently selected from halo, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; L3is an optional substituted or unsubstituted spacer, with the proviso that the linker-drug conjugate at least meets one of the following conditions: 1) L 1b at least one -CH2- in is replaced with 1 or 2 R 1a substituents; each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; 2) L 1b substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3- 7 cycloalkylene or 3-7 membered heterocyclylene; 3) at least one amino acid residue in said L2 is substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a alkyl, C 1-6 alkoxy, C 1-6 alkyl, C 1-6 haloalkyl or C 1-6 haloalkoxy; preferably, L1is L 1a -L 1b -L 1c -L 1d -L 1e -; L 1a for L 1b is C 1-8 alkylene; at least one -CH2- in said alkylene is substituted by 1 or 2 R 1-8 alkylene; at least one -CH2- in said alkylene is substituted by 1 or 2 R 1a substituents; Each R 1a Independently selected from halogen or C 1-6 Alkyl group; or, any two R atoms on the same or different carbon atoms. 1a Can be connected to form C 3-7 Cycloalkylene or 3-7 membered heterocyclic alkylene, preferably C 3-7 Cycloalkylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d C 1-8 alkylene, optionally 1, 2, or 3 non-adjacent carbon atoms in said C 1-8 alkylene are optionally replaced with a heteroatom of O, S, N, and further wherein each -CH2- in said C 1-8 alkylene is optionally substituted with 1 or 2 R 1c substituents; each R is independently selected from H, halogen, or C1-C6alkyl; 1c is independently selected from H, halogen, or C1-C6alkyl; 1-6 alkyl; L 1c and L 1d may be simultaneously a chemical bond, L 1c and L 1d is preferably a chemical bond; L 1e is selected from -C(O)- or -NHC(O)-, preferably -C(O)-; L2is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a alkyl, C 1-6 alkoxy, C 1-6 alkyl, C 1-6 haloalkyl or C 1-6 haloalkoxy; L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-; said L3is optionally substituted with 1, 2, or 3 R 3a substituted; said R 3a selected from H, C 1-6 alkyl or C 1-6 haloalkyl; with the proviso that the linker-drug conjugate at least meets one of the following conditions: 1) L 1b at least one -CH2- in is replaced by 1 or 2 R 1a substituents; each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; 2) L 1b substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3- 7 cycloalkylene or 3-7 membered heterocyclyl ene; 3) at least one amino acid residue in said L2 is substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a halo, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy.

14. The linker-drug conjugate of any one of claims 8-13, wherein: D is derived from a monovalent radical of a compound of formula (D) as described in any one of claims 1-7, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof, for example, selected from the group consisting of compounds of formula (D') of claim 9; L1 is L 1a - L 1b - L 1c - L 1d - L 1e - L 1a for L 1b Selected from C 1-10 Alkylene, C 2-10 imide or C 2-10 Isomerynethiol; the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2-10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1a replace; each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d alkylene, C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, any 1, 2, or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, each -CH2- in said C 1-10 alkylene, C 2- 10 alkenylene, or C 2-10 alkynylene, each -CH2- in said C 1c is optionally substituted with 1 or 2 R each R 1c is independently selected from H, halo, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c groups on any identical or different carbon atom can be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl; n is selected from 1, 2, 3, 4, 5 or 6; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidic radical comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valine (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine; L3 is an optional substituted or unsubstituted spacer.

15. The linker-drug conjugate of any one of claims 8-14, wherein: D is a compound of Formula (D), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: wherein, A1' is selected from -O-C 0-6 alkylene-, -NH-C 0-6 alkylene- or -S-C 0-6 alkylene-; A2is selected from -(CR a R b ) k - -(CR a R b ) k - -(CR a R b ) k - -(CR 3-7 cycloalkylene or 3-7 membered heterocyclylene; k is 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6; each of the other variables in formula (D') is as defined in any one of claims 1-6; L1 is L 1a -L 1b -L 1c -L 1d -L 1e -; L 1a for L 1b alkylene, C 1-10 alkylene, C 2-10 alkylene, C 2-10 alkylene, C 1-10 alkylene, C 2-10 alkylene, C 2-10 alkylene, C 1-10 alkylene, C 2-10 alkylene, C 2-10 alkylene, C 1a alkylene, C each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d Selected from chemical bonds, C 1-10 Alkylene, C 2-10 imide or C 2-10 Imyynyl group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2- 10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1c replace; each R 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1c may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidic radical comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valine (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine; L3 is an optional substituted or unsubstituted spacer; with the proviso that the linker-drug conjugate at least meets one of the following conditions: 1) m is selected from 2, 3, 4, 5 or 6; 2) L1—L2—L3—is not the following structure:

16. The linker-drug conjugate of any one of claims 8-15, wherein, L1 is L 1a -L 1b -L 1c -L 1d -L 1e -; L 1a selected from L 1b selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1a substituted by 1 or 2 R R 1a selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d a chemical bond, C 1-8 alkylene or -(CH2CH2O) w -C 1-4 alkylene; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH2O) n -C 1-4 alkyl or -C(O)NH-(CH2CH2O) n -C 1-4 alkyl; w and n are independently selected from 1, 2, 3, 4, 5 or 6; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; Preferably, L1is selected from each m, w and n is independently selected from 1, 2, 3, 4, 5 or 6; each R is independently selected from H, C 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached collectively form C 3-5 cycloalkylene or 3-5 membered heterocyclylene; More preferably, L1is selected from:

17. The linker-drug conjugate of any one of claims 8-16, wherein, L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; Preferably, L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3, or OCH3; More preferably, L2is selected from: L2 is connected to L1 via the a terminus and to L3 via the b terminus.

18. The linker-drug conjugate of any one of claims 8-17, wherein, L1 is L 1a - L 1b - L 1c - L 1d - L 1e - L 1a selected from L 1b selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1a substituted with 1 or 2 R 1a selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl; L 1b optionally substituted with a hydrophilic group selected from: L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d a chemical bond, C 1-8 alkylene or -(CH2CH2O) w -C 1-4 alkylene; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH2O) n -C 1-4 alkyl or -C(O)NH-(CH2CH2O) n -C 1-4 alkyl; w and n are independently selected from 1, 2, 3, 4, 5 or 6; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-; said L3is optionally substituted with 1, 2, or 3 R 3a substituted; said R 3a selected from H, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy.

19. The linker-drug conjugate of any one of claims 8-18, wherein, L1is selected from the group consisting of each m, w and n is independently selected from 1, 2, 3, 4, 5 or 6; each R is independently selected from H, C 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene or 3-5 membered heterocyclylene; Preferably, L1is selected from: L2 is selected from a divalent peptidyl group comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3, or OCH3; Preferably, L2is selected from: L2 is connected to L1 via the a terminus and to L3 via the b terminus; L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-.

20. The linker-drug conjugate of any one of claims 8-19, wherein, (D-4'). In some embodiments, D is selected from a compound of Formula (D), Formula (D-1), Formula (D-2), Formula (D-3), or Formula (D-4), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: wherein, A1' is a divalent group resulting from the attachment of A1 to the linker, selected from -O-, -OCH2-, -NH-, -NHCH2-, -S- or -SCH2-; each of the other variables is as defined in any one of claims 1-6.

21. The linker-drug conjugate of any one of claims 8-20, wherein, D is selected from the following compounds, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or mixtures thereof:

22. The linker-drug conjugate of any one of claims 8-21, wherein, The linker-drug conjugate is selected from a compound of Formula (LD-1), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof: wherein, Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; m is selected from 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, such as a DNA topoisomerase I inhibitor; Preferably, Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene; m is selected from 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a camptothecin derivative, preferably selected from a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; More preferably, Each R 1a and R 1a’ Independently selected from H or C 1-4 Alkyl groups, such as methyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene; m is selected from 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; (D-5') or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic mixture, polymorph, hydrate, or solvate thereof, or mixtures thereof: k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center, selected from the (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 20.

23. The linker-drug conjugate of any one of claims 8-21, wherein, the linker-drug conjugate is selected from a compound of Formula (LD-2), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or a mixture thereof: each R is independently selected from H, C 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; m is selected from 1, 2, 3, 4, 5 or 6; w and v are independently selected from 1, 2, 3 or 4; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity, such as a DNA topoisomerase I inhibitor; Preferably, Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene; m, w and v are independently selected from 1, 2, 3 or 4; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a camptothecin derivative, preferably selected from a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; More preferably, Each R 1a and R 1a’ Independently selected from H or C 1-4 Alkyl groups, such as methyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene; m is selected from 2, 3 or 4; w is selected from 1, 2 or 3; v is selected from 1, 2 or 3; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; (D-5') or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic mixture, polymorph, hydrate, or solvate thereof, or mixtures thereof: k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 20.

24. The linker-drug conjugate of any one of claims 8-21, wherein, the linker-drug conjugate is selected from a compound of Formula (LD-3), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or a mixture thereof: wherein, Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; m and n are independently selected from 1, 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; D is derived from a monovalent radical of a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; Preferably, Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene, for example cyclopropylene; m is selected from 2, 3, 4, 5 or 6; n is selected from 2, 3 or 4; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; D is selected from a compound of Formula (D-6’), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: k' is selected from 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, more preferably 1; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 20.

25. The linker-drug conjugate of any one of claims 8-21, wherein, the linker-drug conjugate is selected from a compound of Formula (LD-4), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or a mixture thereof: wherein, R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H; D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity, such as a DNA topoisomerase I inhibitor; Preferably, R 1b and R 1b’ are independently selected from H or C 1-6 alkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-5 cycloalkylene; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy; provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H; D is a camptothecin derivative, preferably selected from a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; More preferably, R 1b and R 1b’ are independently selected from H or C 1-4 alkyl, for example H or methyl; alternatively, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene, for example cyclopropylene; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H; D is selected from a compound of Formula (D-5’), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center selected from the (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 20.

26. The linker-drug conjugate of any one of claims 8-25, wherein, the linker-drug conjugate is selected from a compound of Table 1, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof.

27. A Ligand Drug Conjugate of Formula (X), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: T— [L1’— L2— L3— D] (X) y (X) wherein, T is a targeting moiety; D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity; y is selected from 1 to 20; L1' is -L 1a L1' is -L 1b L1' is -L 1c L1' is -L 1d L1' is -L 1e L1' is -L L 1a by a thiol reactive group L 1a reacting with a targeting moiety T, for example L 1a ' connected to T by one end; L 1b selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; optionally 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced by a heteroatom selected from O, S, N; and each -CH2- in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted by 1 or 2 R 1a ; each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d alkylene, C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, wherein any 1, 2, or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, wherein each -CH2- in said C 1-10 alkylene, C 2- 10 alkenylene, or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1c ; each R 1c is independently selected from H, halo, C 1-6 alkyl, C 1-6 haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 alkyl, -NHC(O)-(OC 1- 4alkylene) n -C 1-4 alkyl, -C(O)-(OC 1-4 alkylene) n -C 1-4 alkyl; or, two R 1c groups on the same or different carbon atoms can be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclyl; n is selected from 1, 2, 3, 4, 5 or 6; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidyl group comprising 2 to 8 optionally substituted natural amino acid residues or unnatural amino acid residues, each of said amino acid residues being the same or different and independently of each other selected from the group consisting of residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine; L3 is an optionally substituted or unsubstituted spacer.

28. The Ligand Drug Conjugate of claim 27, wherein: T is a small molecule ligand, such as a folate derivative, a glutamic acid urea derivative, a somatostatin derivative, an arylsulfonamide derivative (e.g. a carbonic anhydrase IX inhibitor), an ICG dye, a cyanine dye or a derivative thereof; Preferably, the ligand is selected from an antibody or an antigen binding fragment thereof, said antibody being selected from a chimeric antibody, a humanized antibody or a fully human antibody; preferably a monoclonal antibody (mAb); Preferably, the antibody or antigen binding fragment thereof is selected from at least one antibody or antigen binding fragment thereof of an anti-CD20 antibody, an anti-CD22 antibody, an anti-CD30 antibody, an anti-CD33 antibody, an anti-CD44 antibody, an anti-CD56 antibody, an anti-CD70 antibody, an anti-CD73 antibody, an anti-CD105 antibody, an anti-CEA antibody, an anti-A33 antibody, an anti-Cripto antibody, an anti-EphA2 antibody, an anti-G250 antibody, an anti-HER2 (ErbB2) antibody, an anti-EGFR antibody, an anti-B7-H3 antibody, an anti-c-Met antibody, an anti-HER3 (ErbB3) antibody, an anti-HER4 (ErbB4) antibody, an anti-MUC1 antibody, an anti-Lewis Y antibody, an anti-VEGFR antibody, an anti-GPNMB antibody, an anti-Integrin antibody, an anti-PSMA antibody, an anti-Tenascin-C antibody, an anti-SLC44A4 antibody or an anti-Mesothelin antibody, which can be a bispecific antibody or a multispecific antibody; Preferably, the antibody or antigen binding fragment thereof is selected from at least one antibody or antigen binding fragment thereof of an anti-CD20 antibody, an anti-CD22 antibody, an anti-CD30 antibody, an anti-CD33 antibody, an anti-CD44 antibody, an anti-CD56 antibody, an anti-CD70 antibody, an anti-CD73 antibody, an anti-CD105 antibody, an anti-CEA antibody, an anti-A33 antibody, an anti-Cripto antibody, an anti-EphA2 antibody, an anti-G250 antibody, an anti-HER2 (ErbB2) antibody, an anti-EGFR antibody, an anti-B7-H3 antibody, an anti-c-Met antibody, an anti-HER3 (ErbB3) antibody, an anti-HER4 (ErbB4) antibody, an anti-MUC1 antibody, an anti-Lewis Y antibody, an anti-VEGFR antibody, an anti-GPNMB antibody, an anti-Integrin antibody, an anti-PSMA antibody, an anti-Tenascin-C antibody, an anti-SLC44A4 antibody or an anti-Mesothelin antibody, which can be a bispecific antibody or a multispecific antibody; Preferably, the antibody or antigen-binding fragment thereof is selected from at least one antibody or antigen-binding fragment thereof of Trastuzumab, Patritumab, Pertuzumab, Nimotuzumab, Enoblituzumab, Emibetuzumab, Inotuzumab, Pinatuzumab, Brentuximab, Gemtuzumab, Bivatuzumab, Lorvotuzumab, cBR96, and Glematumamab or Glembatumumab; More preferably, T is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab.

29. The ligand drug conjugate of claim 27 or 28, wherein, D is derived from a monovalent radical of a compound of formula (D) as defined in any one of claims 1 to 7, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; Preferably, D is a compound of Formula (D’), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or mixtures thereof: wherein, A1' is selected from -O-C 0-6 alkylene-, -NH-C 0-6 alkylene- or -S-C 0-6 alkylene-; each of the other variables is as defined in any one of claims 1 to 6.

30. The Ligand Drug Conjugate of any one of claims 27 to 29, wherein: L1' is -L 1a L1' is -L 1b L1' is -L 1c L1' is -L 1d L1' is -L 1e L1' is -L L 1a ’ selected from L 1a ' connected to T by a terminal; L 1b Selected from C 1-10 Alkylene, C 2-10 imide or C 2-10 Isomerynethiol; the C 1-10 Alkylene, C 2-10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1a replace; each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d alkylene, C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, any 1, 2, or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene, each -CH2- in said C 1-10 alkylene, C 2- 10 alkenylene, or C 2-10 alkynylene, each -CH2- in said C 1c is optionally substituted with 1 or 2 R each R is independently selected from H, halogen, C 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidic radical comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being identical or different, independently from each other, selected from the group consisting of the residues of the amino acids alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), norvaline (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine, preferably L2 is selected from a divalent peptidic radical comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a halo, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; L3 is an optionally substituted or unsubstituted spacer, with the proviso that the Ligand Drug Conjugate at least meets one of the following conditions: 1) L 1b at least one -CH2- in is replaced by 1 or 2 R 1a substituents; each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; 2) L 1b substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3- 7 cycloalkylene or 3-7 membered heterocyclyl ene; 3) at least one amino acid residue in said L2 is substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a alkyl, C 1-6 alkoxy, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; Preferably, L1' is -L 1a L1' is -L 1b L1' is -L 1c L1' is -L 1d L1' is -L 1e L1' is -L L 1a ’ selected from L 1a ' connected to T by one end; L 1b is C 1-8 alkylene; at least one -CH2- in said alkylene is substituted by 1 or 2 R 1-8 alkylene; at least one -CH2- in said alkylene is substituted by 1 or 2 R 1a substituents; each R 1a is independently selected from halogen or C 1-6 alkyl; or, two R 1a may be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl, preferably C 3-7 cycloalkylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d alkylene, said C 1-8 alkylene, said C 1-8 any 1, 2, or 3 non-adjacent carbon atoms in said C 1-8 alkylene, each -CH2- in said C 1c alkylene is optionally substituted with 1 or 2 R each R is independently selected from H, halogen, or C1-C6alkyl; 1c is independently selected from H, halogen, or C1-C6alkyl; 1-6 alkyl; L 1c and L 1d may be simultaneously a chemical bond, L 1c and L 1d is preferably a chemical bond; L 1e is selected from -C(O)- or -NHC(O)-, preferably -C(O)-; L2 is selected from a divalent peptidic radical comprising 2 to 6 amino acid residues, each amino acid residue being independently selected from the group consisting of glycine, phenylalanine and alanine; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from halo, C 2a halo, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-; said L3is optionally substituted with 1, 2, or 3 R 3a substituted; said R 3a selected from H, C 1-6 alkyl or C 1-6 haloalkyl; with the proviso that the Ligand Drug Conjugate at least meets one of the following conditions: 1) L 1b at least one -CH2- in is replaced by 1 or 2 R 1a substituents; each R 1a is independently selected from halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; 2) L 1b substituted with a hydrophilic group selected from: R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3- 7 cycloalkylene or 3-7 membered heterocyclylene; 3) at least one amino acid residue in said L2 is substituted with 1, 2, or 3 R 2a substituted; Each R 2a Independently selected from halogens, C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Halogenated alkyl or C 1-6 Halogenated alkoxy groups.

31. The Ligand Drug Conjugate of any one of claims 27 to 30, wherein: D is a monovalent radical derived from a compound of formula (D) as described in any one of claims 1 to 7, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or mixtures thereof, for example, selected from the group consisting of compounds of formula (D') of claim 29; L1' is -L 1a L1' is -L 1b L1' is -L 1c L1' is -L 1d L1' is -L 1e L1' is -L L 1a ’ for L 1a ' connected to T by one end; L 1b any 1, 2, or 3 non-adjacent carbon atoms in the C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene; each -CH2- in the C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally replaced with a heteroatom of O, S, N, while, C 1-10 alkylene, C 2-10 alkenylene, or C 2-10 alkynylene is optionally substituted with 1 or 2 R 1a substituents; each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d Selected from chemical bonds, C 1-10 Alkylene, C 2-10 imide or C 2-10 Idemyne ​​group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2- 10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1c replace; Each R 1c Independently selected from H, halogen, C 1-6 Alkyl, C 1-6 Haloalkyl, -NHC(O)-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -C(O)NH-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -NH-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -C(O)-(C 1-4 alkylene-O) n -C 1-4 Alkyl, -NHC(O)-(OC) 1- 4-alkylene) n -C 1-4 Alkyl, -C(O)-(OC) 1-4 Alkylene) n -C 1-4 Alkyl group; or, any two R atoms on the same or different carbon atoms. 1c Can be connected to form C 3-10 Cycloalkylene or 3-10 membered heterocyclic cycloalkylene groups; n is selected from 1, 2, 3, 4, 5 or 6; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidic radical comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valinol (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine; L3 is an optional substituted or unsubstituted spacer.

32. The Ligand Drug Conjugate of any one of claims 27-31, wherein: D is a compound of Formula (D), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: wherein, A2is selected from -(CR a R b ) k - -(CR a R b ) k -0-(CR a R b ) k - C 3-7 cycloalkyl or 3-7 membered heterocyclyl; k is 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6; each of the other variables in formula (D') is as defined in any one of claims 1 to 6; L1' is -L 1a L1' is -L 1b L1' is -L 1c L1' is -L 1d L1' is -L 1e L1' is -L L 1a ’ selected from L 1a ' connected to T by one end; L 1b selected from C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene; any 1, 2 or 3 non-adjacent carbon atoms in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene are optionally replaced by a heteroatom selected from O, S, N, and each -CH2- in said C 1-10 alkylene, C 2-10 alkenylene or C 2-10 alkynylene is optionally substituted by 1 or 2 R 1a ; each R 1a is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1b optionally substituted with a hydrophilic group selected from: R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1- 6haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d Selected from chemical bonds, C 1-10 Alkylene, C 2-10 imide or C 2-10 Imyynyl group, the C 1-10 Alkylene, C 2-10 imide or C 2-10 In the ynynyl group, any one, two, or three non-adjacent carbon atoms are optionally replaced by heteroatoms of O, S, or N, while C 1-10 Alkylene, C 2- 10 imide or C 2-10 Each -CH2- in the ynyl group is optionally surrounded by one or two R groups. 1c replace; each R 1c is independently selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1c may be joined to form a C 3-10 cycloalkylene or 3-10 membered heterocyclylene; L 1c and L 1d may be simultaneously a chemical bond; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidic radical comprising 2 to 8 optionally substituted natural or unnatural amino acid residues, each of said amino acid residues being the same or different, independently of each other, selected from the group consisting of the residues of the following amino acids: alanine (Ala), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), phenylalanine (Phe), glycine (Gly), histidine (His), isoleucine (lie), lysine (Lys), leucine (Leu), methionine (Met), asparagine (Asn), proline (Pro), glutamine (Gin), arginine (Arg), serine (Ser), threonine (Thr), valine (Val), tryptophan (Trp), tyrosine (Tyr), citrulline (Cit), valinol (Nva), norleucine (Nle), selenocysteine (Sec), pyrrolysine (Pyl), homoserine, homocysteine, desmethylpyrrolysine; L3 is an optional substituted or unsubstituted spacer; with the proviso that the linker-drug conjugate at least meets one of the following conditions: 1 ) m is selected from 2, 3, 4, 5 or 6; 2) L1' - L2- L3- is not the following structure:

33. The Ligand Drug Conjugate of any one of claims 27-32, wherein, L1' is L 1a ' - L 1b - L 1c - L 1d - L 1e - ; L 1a ’ selected from is connected to T via the # end; L 1b selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1a substituted with 1 or 2 R 1a selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl; L 1b optionally substituted with a hydrophilic group selected from: L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d selected from a chemical bond, C 1-8 alkylene or -(CH2CH2O) w -C 1-4 alkylene-; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH2O) n -C 1-4 alkyl or -C(O)NH-(CH2CH2O) n -C 1-4 alkyl; w and n are independently selected from 1, 2, 3, 4, 5 or 6; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; Preferably, L1' is selected from L1' is connected to T via the # end; each m, w and n are independently selected from 1, 2, 3, 4, 5 or 6; Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene or 3-5 membered heterocyclylene; More preferably, L1' is selected from: L1' is connected to T via the # end.

34. Ligand drug conjugate according to any one of claims 27 to 33, wherein L2 is selected from a divalent peptidic group consisting of 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; Preferably, L2 is selected from a divalent peptidic group consisting of 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3, or OCH3; More preferably, L2is selected from: L2 is connected to L1 via the a end and to L3 via the b end.

35. Ligand drug conjugate according to any one of claims 27 to 34, wherein L1' is L 1a ' - L 1b - L 1c - L 1d - L 1e - ; L 1a ’ selected from is connected to T via the # end; L 1b selected from C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1-8 alkylene, -(CH2CH20) w -C 1-4 alkylene-, C 2-8 alkenylene or C 2-8 alkynylene, each -CH2- in said C 1a substituted with 1 or 2 R 1a selected from H, halogen, C 1-6 alkyl or C 1-6 haloalkyl; or, two R 1a on any identical or different carbon atom can be joined to form a C 3-7 cycloalkylene or 3-7 membered heterocyclyl; L 1b optionally substituted with a hydrophilic group selected from: L 1c is selected from a chemical bond, -C(O)-, -C(O)NH-, or -NHC(O)-; L 1d selected from a chemical bond, C 1-8 alkylene or -(CH2CH2O) w -C 1-4 alkylene-; said C 1-8 alkylene is optionally substituted with -NHC(O)-(CH2CH2O) n -C 1-4 alkyl or -C(O)NH-(CH2CH2O) n -C 1-4 alkyl; w and n are independently selected from 1, 2, 3, 4, 5 or 6; L 1e is selected from -C(O)-, -NHC(O)- or -C(O)-NHC(O)-; L2 is selected from a divalent peptidic group consisting of 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-.

36. Ligand drug conjugate according to any one of claims 27 to 35, wherein L1' is selected from each m, w and n are independently selected from 1, 2, 3, 4, 5 or 6; Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene or 3-5 membered heterocyclylene; Preferably, L1' is selected from: L1' is connected to T via the # end; L2 is selected from a divalent peptidic group consisting of 2 to 6 amino acid residues, each amino acid residue being independently selected from glycine, phenylalanine and alanine, preferably -GlyGlyPheGly- or -AlaAlaAla-; each amino acid residue in said L2 is optionally substituted with 1, 2, or 3 R 2a substituents; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy, for example H, F, CH3, or OCH3; Preferably, L2is selected from: L2 is connected to L1 via the a end and to L3 via the b end. L3is selected from -NH-CH2-(AM), (PABC), preferably -NH-CH2-.

37. The ligand drug conjugate of any one of claims 27-36, wherein, (D-4'). In some embodiments, D is selected from a compound of Formula (D), Formula (D-1), Formula (D-2), Formula (D-3), or Formula (D-4), or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or mixtures thereof: wherein A1' is a divalent group resulting from the attachment of A1 to the linker, selected from -O-, -OCH2-, -NH-, -NHCH2-, -S- or -SCH2-; each of the other variables is as defined in any one of claims 1 to 6; Preferably, said D is selected from:

38. The ligand drug conjugate of any one of claims 27-37, wherein, The ligand drug conjugate is selected from a compound of Formula (X-la), (X-lb), or (X-lc), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: wherein mAb is a monoclonal antibody; y is selected from 1 to 20, preferably 1 to 10; each R is independently selected from H, C 1a and R 1a’ is independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; m is selected from 1, 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a biologically active fragment, preferably a molecular fragment having anti-tumor biological activity, such as a DNA topoisomerase I inhibitor; Preferably, mAb is a monoclonal antibody; y is selected from an integer or a decimal number from 1 to 10; Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene; m is selected from 1, 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a camptothecin derivative, preferably selected from a compound according to any one of claims 1 to 7, or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; More preferably, mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab; y is selected from an integer or a decimal number from 4 to 10; Each R 1a and R 1a’ Independently selected from H or C 1-4 Alkyl groups, such as methyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene; m is selected from 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is selected from a compound of Formula (D-5’), or a pharmaceutically acceptable salt, isotopolog, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center selected from (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 37.

39. The ligand drug conjugate of any one of claims 27-37, wherein, The ligand drug conjugate is selected from a compound of Formula (X-2a), (X-2b), or (X-2c), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: mAb is a monoclonal antibody; y is selected from an integer or a decimal number from 1 to 20, preferably from 1 to 10; Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; m is selected from 1, 2, 3, 4, 5 or 6; w and v are independently selected from 1, 2, 3 or 4; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity, such as a DNA topoisomerase I inhibitor; Preferably, mAb is a monoclonal antibody; y is selected from an integer or a decimal number from 4 to 10; Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene; m, w and v are independently selected from 1, 2, 3 or 4; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; D is a camptothecin derivative, preferably selected from a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or a mixture thereof; More preferably, mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab; y is selected from an integer or a decimal number from 4 to 10; Each R 1a and R 1a’ Independently selected from H or C 1-4 Alkyl groups, such as methyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene; m is selected from 2, 3 or 4; w is selected from 1, 2 or 3; v is selected from 1, 2 or 3; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; provided that all R 1a , R 1a’ and 5 R 2a are not simultaneously H; (D-5') or a pharmaceutically acceptable salt, isotopically enriched variant, tautomer, stereoisomer, racemic mixture, polymorph, hydrate, or solvate thereof, or mixtures thereof: k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center selected from (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 37.

40. The ligand drug conjugate of any one of claims 27-37, wherein, The ligand drug conjugate is selected from a compound of Formula (X-3), or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof: wherein, mAb is a monoclonal antibody; y is selected from an integer or a decimal number from 2 to 20, preferably from 3 to 10; Each R 1a and R 1a’ Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-7 cycloalkylene or 3-7 membered heterocyclylene; m and n are independently selected from 1, 2, 3, 4, 5 or 6; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; D is derived from a monovalent radical of a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopic variant, tautomer, stereoisomer, racemic, polymorph, hydrate or solvate thereof, or a mixture thereof; Preferably, mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab; y is selected from an integer or a decimal number from 4 to 10; Each R 1a and R 1a’ Independently selected from H or C 1-6 alkyl; or R on any carbon atom 1a , R 1a’ and the carbon atom to which they are attached together form C 3-5 cycloalkylene, for example cyclopropylene; m is selected from 2, 3, 4, 5 or 6; n is selected from 2, 3 or 4; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; D is selected from a compound of Formula (D-6’), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: k' is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 1, 2 or 3, more preferably 1 ; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkylene, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 37.

41. The ligand drug conjugate of any one of claims 27-37, wherein, The ligand drug conjugate is selected from a compound of Formula (X-4a), (X-4b), or (X-4c), or a pharmaceutically acceptable salt, isotopologues, tautomer, stereoisomer, racemic, polymorph, hydrate, or solvate thereof, or mixtures thereof: wherein, mAb is a monoclonal antibody; y is selected from an integer or a decimal number from 2 to 20, preferably from 3 to 10; R 1b and R 1b’ are independently selected from H, C 1-6 alkyl or C 1-6 haloalkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-7 cycloalkylene or 3-7 membered heterocyclyl ene; each R is independently selected from H, halogen, C 2a is independently selected from H, halogen, C 1-6 alkyl, C 1-6 alkoxy, C 1-6 haloalkyl or C 1-6 haloalkoxy; provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H; D is a biologically active fragment, preferably a molecular fragment having an anti-tumor biological activity, such as a DNA topoisomerase I inhibitor; Preferably, mAb is a monoclonal antibody; y is selected from an integer or a decimal number from 4 to 10; R 1b and R 1b’ are independently selected from H or C 1-6 alkyl; or, R 1b , R 1b’ and the carbon atom to which they are attached collectively form C 3-5 cycloalkylene; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy; provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H; D is a camptothecin derivative, preferably a monovalent radical derived from a compound of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; More preferably, mAb is Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab; y is selected from an integer or a decimal number from 4 to 10; R 1b and R 1b’ are independently selected from H or C 1-4 alkyl, for example H or methyl; alternatively, R 1b , R 1b’ and the carbon atom to which they are attached together form a C 3-5 cycloalkylene, for example cyclopropylene; each R is independently selected from H, halogen, C 2a independently selected from H, halogen, C 1-6 alkyl or C 1-6 alkoxy, for example H, F, methyl or methoxy; provided that all R 1b , R 1b’ and 5 R 2a are not simultaneously H; D is selected from a compound of Formula (D-5’), or a pharmaceutically acceptable salt, isotopolog, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or mixtures thereof: k is selected from 1, 2, 3, 4, 5 or 6, preferably 2, 3, 4, 5 or 6, preferably 2, 3 or 4, more preferably 2; Each R a and R b Independently selected from H and C 1-6 Alkyl or C 1-6 Halogenated alkyl groups, preferably H or C 1-4 Alkyl groups, such as H or methyl groups; * is a chiral center selected from (S) or (R) absolute configuration, or a mixture thereof; R1and R2are independently selected from H or C 1-6 alkyl; or R1and R2or the carbon atom to which R2is attached are linked to form C 5-7 cycloalkyl, preferably forming a six-membered cycloalkyl group; R3is selected from C 1-6 alkyl or C 1-6 haloalkyl, preferably C 1-6 alkyl, more preferably C 1-4 alkyl, for example methyl; R4is selected from halogen, OH, NH2or C 1-6 alkyl, preferably halogen, more preferably F; R5 is OH; R6is selected from -C 1-4 alkylene-C 3-5 cycloalkyl, for example -CH2-cyclopropyl; Said D is more preferably a compound of formula (D-1') or (D-2'), wherein each group is as defined in claim 37.

42. The ligand drug conjugate of any one of claims 27-41, wherein, Said Ligand Drug Conjugate is selected from a compound of Table 2-1, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof, wherein mAb is a monoclonal antibody, preferably Trastuzumab, Patritumab, Pertuzumab or Nimotuzumab, more preferably Trastuzumab; y is selected from an integer or a decimal number from 0 to 20, preferably from 0 to 10; more preferably, y is selected from an integer or a decimal number from 4 to 10; Preferably, said Ligand Drug Conjugate is selected from a compound of Table 2-2, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; Preferably, the -L-D structure in said Ligand Drug Conjugate is linked to a cysteine in mAb.

43. A pharmaceutical composition comprising at least one selected from: a compound of formula (D) of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; and / or a Ligand Drug Conjugate of formula (X) of any one of claims 27-42, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof.

44. A method for preventing and / or treating a disease in a subject in need thereof, comprising administering to the subject: a compound of formula (D) of any one of claims 1-7, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate or solvate thereof, or a mixture thereof; or The ligand drug conjugate of Formula (X) as described in any one of claims 27-42, or a pharmaceutically acceptable salt, isotopologue, tautomer, racemate, stereoisomer, polymorph, hydrate, or solvate thereof, or a mixture thereof.

45. The compound of Formula (D) as described in any one of claims 1-7, the linker-drug conjugate as described in any one of claims 8-26, or the ligand drug conjugate of Formula (X) as described in any one of claims 27-42, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof, for use in the prevention and / or treatment of a disease.

46. Use of the compound of Formula (D) as described in any one of claims 1-7, the linker-drug conjugate as described in any one of claims 8-26, or the ligand drug conjugate of Formula (X) as described in any one of claims 27-42, or a pharmaceutically acceptable salt, isotopologue, tautomer, stereoisomer, racemate, polymorph, hydrate, or solvate thereof, or a mixture thereof, for the manufacture of a medicament for the prevention and / or treatment of a disease.

47. The method of claim 44, the compound of claim 45, the linker-drug conjugate or the ligand drug conjugate, or the use of claim 46, wherein, the disease is selected from a tumor, such as a sarcoma or a carcinoma; Preferably, the disease is selected from leukemia, fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma, lymphoma, lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, gastric cancer, colon cancer, rectal cancer, small intestine cancer, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinoma, cystadenocarcinoma, medullary carcinoma, bronchogenic carcinoma, esophageal carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilms' tumor, cervical cancer, uterine cancer, testicular cancer, lung cancer, small cell lung carcinoma, non-small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, schwannoma, meningioma, melanoma, neuroblastoma, and retinoblastoma; More preferably, the disease is a carcinoma selected from breast cancer and gastric cancer.

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