Ligand-drug conjugate, preparation method therefor and use thereof

Abstract

The present disclosure relates to a ligand-drug conjugate, a preparation method therefor and a use thereof, and relates to a ligand-drug conjugate having a structure represented by formula (I) or a pharmaceutically acceptable salt thereof, or a compound having a structure represented by formula (IA) or formula (IIA) or a tautomer, mesomer, racemate, enantiomer, diastereomer or mixture thereof, or a pharmaceutically acceptable salt thereof, a preparation method therefor, a composition thereof, and a use thereof in treatment and / or prevention of tumors.

Description

Ligand-drug conjugate, preparation method and application thereof TECHNICAL FIELD

[0001] The present disclosure belongs to the field of medicine, and relates to a new camptothecin compound, a ligand-drug conjugate based on the camptothecin toxin, and a preparation method and application thereof. BACKGROUND

[0002] Ligand-drug conjugate (e.g. ADC) is a molecular form of conjugating ligand (e.g. antibody or fragment thereof) recognizing specific antigen on tumor cell surface with bioactive payload (i.e. toxin, e.g. small molecule drug) through stable chemical linker. With specific interaction between ligand (e.g. monoclonal antibody) and antigen, ligand-drug conjugate can accurately deliver payload to target cell, be cleaved and released at tumor, thereby changing distribution and metabolism of small molecule drug, reducing minimum effective dose (MED) of payload, and expanding safety window of treatment.

[0003] Targeted delivery of small molecule drug to tumor cells expressing antigen is the mode of action of ADC, which also requires ADC molecules to meet the following requirements: 1. The molecule can be effectively internalized into tumor cells; 2. The linker part remains stable during circulation; and 3. The linker part can be quickly released in the lysosome of tumor cells. ADC molecules meeting these requirements will have a good therapeutic window in animal studies and clinical trials.

[0004] Camptothecin is a class of pentacyclic quinoline alkaloids, which exhibit potent antitumor activity through inhibition of topoisomerase I, which is essential for the physiological function of cells and overexpressed in various tumor cell lines. So far, only three camptothecin-based chemotherapeutic agents have been approved by regulatory authorities, including topotecan, irinotecan and belotecan. Due to the narrow therapeutic window found in clinical trials, other members of the camptothecin family have almost no success in commercialization.

[0005] In order to broaden the therapeutic window of camptothecin, as verified in clinical trials, it seems to be a good choice to prepare ADC based on camptothecin. From anti-Trop2 ADC (Trodelvy TM , Gilead) and anti-Her2 ADC (Enhertu TMSince the successful commercialization of Kadcyla (Roche) and Enhertu (Daiichi Sankyo), camptothecin (CPT) derivatives have gained most of the attention in the ADC linker-payload research field. The existence of these two products has completely changed the concept of ADC design, which has changed the "low drug-load, but high payload-efficacy" model to the "high payload-load, but acceptable payload efficacy" model. In particular, for Enhertu TM , the linker design has a relatively stable design during the circulation, even in Her2 + , and has shown promising clinical results in breast cancer patients.

[0006] Although more than 10 different camptothecin-based linker-payloads have entered clinical trials, most of the linker-payload designs are derived from exatecan or Dxd (CAS: 1599440-33-1). The high structural similarity of these linker-payloads to Enhertu TM may also indicate that they have a high possibility of causing fatal adverse treatments in clinical applications, such as interstitial lung diseases (ILDs). In order to overcome the adverse effects of Enhertu, it is necessary and urgent to find new camptothecin derivatives that have significant structural differences from exatecan (Exatecan) and to develop certain aspects of ligand-drug conjugates that are more effective based on these new camptothecin derivatives. SUMMARY

[0007] The present disclosure provides a compound (including a ligand-drug conjugate) or a tautomer, meso-form, racemate, enantiomer, diastereomer, or a mixture thereof, or a pharmaceutically acceptable salt thereof, which can have one or more effects selected from the group consisting of: (1) an in vitro proliferation inhibitory activity against tumor cells, (2) a targeted inhibitory effect, (3) a plasma stability, (4) an in vivo tumor inhibitory effect, (5) a bystander effect, (6) an anti-transporter transport ability, (7) an in vivo tumor targeting ability, and (8) a good in vivo safety. The aforementioned compound provided by the present disclosure can be used as a drug for treating cancer. The present disclosure also provides a method and use of the aforementioned compound for cancer treatment.

[0008] A first aspect of the present disclosure relates to a ligand-drug conjugate or a pharmaceutically acceptable salt thereof, wherein the ligand-drug conjugate has a structure represented by Formula (I):

[0009] mAb— (L— D)z Formula (I);

[0010] wherein mAb is a ligand that binds to a target;

[0011] z is the average drug ligand coupling ratio, z is selected from the group consisting of an integer or decimal number from about 1 to about 16;

[0012] L is a linking unit having the following structure: -L4-L3-L2-L1-; wherein,

[0013] said L4 is selected from the group consisting of wherein m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, 1 is attached to the ligand, and 2 is attached to L3; R X selected from the group consisting of C 1-6 alkyl and C 3-6 cycloalkyl, said C 1-6 alkyl and C 3-6 cycloalkyl are optionally substituted with one or more substituents selected from the group consisting of halogen, cyano, hydroxy, C 1-6 alkyl and C 3-6 cycloalkyl;

[0014] said L3 is selected from the group consisting of wherein s is an integer from 1 to 30, 1 is attached to L4, and 2 is attached to L2;

[0015] said L2 is an amino acid or a peptide consisting of 2 to 10 amino acids; said amino acid is selected from the group consisting of a natural amino acid residue, a non-natural amino acid residue, or a stereoisomer thereof; when said amino acid residue is Lys, the side chain amino group of said Lys is optionally substituted with 1, 2, or 3 C 1-6 alkyl groups;

[0016] said L1 is absent or is a self-immolative unit;

[0017] D is a drug having the structure shown in formula (II):

[0018] wherein the wavy line represents the bond connecting L and D;

[0019] R 1 , R 2 , and R 3 are each independently selected from the group consisting of hydrogen, halogen, cyano, hydroxy, C 1-6 alkyl, C 1-6 haloalkyl, and C 1-6 alkoxy;

[0020] W is selected from the group consisting of wherein R 4 , R 5 , R 6 , R 7 , R 8 , and R 9 are each independently selected from the group consisting of hydrogen, C 1-6 alkyl, C 1-6heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-8 cycloalkyl, C 6-14 aryl and C 6-14 aryl-C 1-6 alkyl, or R 4 and R 5 together with the N to which they are attached form C 3-8 heterocyclyl, or R 6 and R 7 together with the N and O to which they are attached form C 3-8 heterocyclyl; said C 1-6 alkyl, C 1-6 heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-8 cycloalkyl, C 6-14 aryl, C 6-14 aryl-C 1-6 alkyl and C 3-8 heterocyclyl is optionally substituted with one or more substituents selected from halo, cyano, hydroxyl, C 1-6 alkyl, C 1-6 alkoxy and C 3-6 cycloalkyl.

[0021] Another aspect of the present disclosure relates to a compound, or a tautomer, mesomer, racemate, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound has a structure according to Formula (IA):

[0022] wherein L is a linking unit having the following structure: L4’—L3—L2—L1—;

[0023] said L4’ is selected from wherein m1 is an integer from 1-5, m2 is an integer from 0-5, 2 is connected to L3; R X is selected from C 1-6 alkyl and C 3-6 cycloalkyl, said C 1-6 alkyl and C 3-6 cycloalkyl is optionally substituted with one or more substituents selected from halo, cyano, hydroxyl, C 1-6 alkyl and C 3-6 cycloalkyl; G1and G2are leaving groups;

[0024] L3, L2, L1, and D are as described in detail herein.

[0025] Another aspect of the present disclosure relates to a compound, or a tautomer, meso, racemic, enantiomeric, diastereomeric isomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound has the structure of Formula (IIA):

[0026] wherein R 1 , R 2 , R 3 and W are as described in detail herein.

[0027] Another aspect of the present disclosure relates to a method of making a Ligand- Drug Conjugate of the present disclosure, or a pharmaceutically acceptable salt thereof, having the structure of Formula (I), comprising contacting a Ligand mAb with a compound of the present disclosure having the structure of Formula (IA).

[0028] Another aspect of the present disclosure relates to a pharmaceutical composition comprising a Ligand-Drug Conjugate of the present disclosure (e.g., Formula (I)), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0029] Another aspect of the present disclosure relates to a pharmaceutical composition comprising a compound of the present disclosure (e.g., Formula (IIA)), or a tautomer, meso, racemic, enantiomeric, diastereomeric isomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0030] Another aspect of the present disclosure relates to the use of a Ligand-Drug Conjugate of the present disclosure (e.g., Formula (I)), or a pharmaceutically acceptable salt thereof, or a compound of the present disclosure (e.g., Formula (IA), Formula (IIA)), or a tautomer, meso, racemic, enantiomeric, diastereomeric isomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the present disclosure, in the manufacture of a medicament for treating and / or preventing a tumor.

[0031] The present disclosure also provides a method of treating and / or preventing a tumor, comprising administering to a subject in need thereof a Ligand-Drug Conjugate of the present disclosure (e.g., Formula (I)), or a pharmaceutically acceptable salt thereof, or a compound of the present disclosure (e.g., Formula (IIA)), or a tautomer, meso, racemic, enantiomeric, diastereomeric isomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the present disclosure.

[0032] The present disclosure also provides a ligand-drug conjugate of the present disclosure (e.g., Formula (I)) or a pharmaceutically acceptable salt thereof, or a compound of the present disclosure (e.g., Formula (IIA)) or a tautomer, mesomer, racemate, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the present disclosure for use in the treatment and / or prevention of a tumor.

[0033] The present disclosure also provides a kit comprising a ligand-drug conjugate of the present disclosure (e.g., Formula (I)) or a pharmaceutically acceptable salt thereof, or a compound of the present disclosure (e.g., Formula (IIA)) or a tautomer, mesomer, racemate, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of the present disclosure.

[0034] The details of the application are set forth in the accompanying description below. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, illustrative methods and materials are described hereinafter. Other features, objects, and advantages of the application will be apparent from the description and from the claims. In the specification and the appended claims, the singular forms also include the plural unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. All patents and publications cited in this specification are incorporated herein by reference in their entireties.

[0035] The contents of all references (including literature references, issued patents, published patent applications, and co-pending patent applications) cited throughout this application are hereby expressly incorporated by reference. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a graph of the results of the efficacy testing of ADC on JIMT-1 cell line subcutaneous xenograft tumors in CB17 / SCID female mice.

[0037] FIG. 2 is the results of the efficacy testing of ADC on JIMT-1 cell line subcutaneous

[0038] FIG. 3 is a graph of the results of the efficacy testing of ADC on JIMT-1 cell

[0039] FIG. 4 is the results of the efficacy testing of ADC on JIMT-1 cell line subcutaneou

[0040] Figure 5 is a graph of the results of the efficacy testing of the ADC on subcutaneous xenograft tumors of NCI-H2110 cell line in CB17 / SCID female mice.

[0041] Figure 6 is the results of the efficacy testing of the ADC on subcutaneous xenograft tumors of NCI-H2110 cell line in CB17 / SCID female mice at day 16. DETAILED DESCRIPTION

[0042] DEFINITIONS

[0043] Unless otherwise indicated, the terms used in the specification and claims have the following meanings.

[0044] In the present disclosure, the term "ligand" generally refers to a macromolecular compound that can recognize and bind to an antigen or receptor associated with a target cell. The role of a ligand can be to deliver a drug to a target cell population that binds to the ligand, which includes but is not limited to proteinaceous hormones, lectins, growth factors, antibodies or other molecules that can bind to cells, receptors and / or antigens. In the present disclosure, the ligand can be denoted as BA, the ligand antigen forms a linkage with the linking unit through a heteroatom on the ligand, which can be an antibody or an antigen-binding fragment thereof, which can be selected from a chimeric antibody, a humanized antibody, a fully human antibody or a murine antibody; the antibody can be a monoclonal antibody. For example, the antibody can be an antibody targeting HER2, HER3, B7H3, TROP2, Claudin 18.2, CD30, CD33, CD70 or EGFR. For example, the antibody can be an antibody targeting 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, 0772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79b, CCL5, CCR5, CCR7, CD11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD40, CD45, CD45 (PTPRC), CD46, CD47, CD49D (ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.2, c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EGFRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRa, GD2, GEDA, GPC-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra, IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP14, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC39A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, proteoglycans, mesothelin, endoglin receptor, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin a4b7, integrin a5b6, trophoblast glycoprotein, or tissue factor.

[0045] In the present disclosure, the term "drug" or "toxin" generally refers to a cytotoxic drug, which is a chemical molecule that can have a strong destructive effect on the normal growth of tumor cells. A cytotoxic drug can kill tumor cells at a sufficiently high concentration. The "cytotoxic drug" can include a toxin, such as a small molecule toxin or an enzymatically active toxin of bacterial, fungal, plant, or animal origin, a radioisotope (e.g., At 211 , I 131 , I 125 , Y 90 , Re186 , Re 188 , Sm 153 , Bi 212 , P 32 or Lu), toxic drugs, chemotherapeutic drugs, antibiotics, and nucleolytic enzymes. The cytotoxic drug in the present disclosure is a camptothecin compound.

[0046] In the present disclosure, the term "linking unit" generally refers to a chemical structure fragment or bond that connects one end to a ligand and the other end to a cytotoxic drug, and can be connected to other linkers before being connected to a cytotoxic drug. The direct or indirect connection to a ligand can mean that the group is directly connected to the ligand through a covalent bond, or is connected to the ligand through a linking unit. For example, the linking unit can be a structure represented by -L4-L3-L2-L1- as described in the present disclosure. For example, a chemical structure fragment or bond comprising an acid-labile linker structure (e.g., a hydrazone), a protease-sensitive (e.g., a peptidase-sensitive) linker structure, a photo-labile linker structure, a dimethyl linker structure, and / or a disulfide-containing linker structure can be used as a linking unit.

[0047] In the present disclosure, the term "self-cleavage unit" refers to a linker structure unit that is interposed between a conditionally cleavable unit and a cytotoxic drug. The mechanism of action of the self-cleavage unit is that when the conditionally cleavable unit is cleaved under suitable conditions, the self-cleavage unit is able to spontaneously undergo structural rearrangement, thereby releasing the cytotoxic drug connected thereto. Common self-cleavage units include p-aminobenzyl alcohols (PAB), substituted or unsubstituted aminomethylene , etc. The self-cleavage unit in the present disclosure is, for example, L1.

[0048] In the present disclosure, the term "conditionally cleavable unit" refers to a linker structure unit that will undergo cleavage under certain conditions within a target cell. Conditionally cleavable units can be divided into two main categories: chemically unstable linkers and enzymatically unstable linkers. Chemically unstable linkers can be selectively cleaved due to the difference in plasma and cytoplasmic properties. Such properties include pH, glutathione concentration, etc. pH-sensitive linkers, also known as acid-cleavable linkers. Such linkers will be hydrolyzed in weakly acidic endosomes (pH 5.0-6.5) and lysosomes (pH 4.5-5.0), such as hydrazones, carbonates, acetals, ketals. Glutathione-sensitive linkers, also known as disulfide linkers. The low oxygen content of tumor cells leads to an increase in the activity of reductases, thus leading to a higher glutathione concentration. The difference in glutathione concentration between tumor cells (millimolar range) and blood (micromolar range) will cause the cleavage of the linker structure. Enzymatically unstable linkers, such as peptide linkers, can be effectively cleaved by lysosomal proteases (such as Cathepsin B) or plasmin (which is increased in some tumor tissues). Typical enzymatically unstable linkers include Val-Cit (VC), Phe-Lys, etc. The conditionally cleavable unit in the present disclosure is, for example, L2.

[0049] In the present disclosure, the term "hydrophilic unit" refers to a linker structure unit with a strong hydrophilic group. The hydrophilic unit can generally adjust the hydrophilic effect of the overall molecule. Common hydrophilic groups include polyethylene glycol groups, etc. The hydrophilic unit in the present disclosure is, for example, L3.

[0050] In the present disclosure, the term "ligand-attached unit" refers to a linker structure unit directly connected to a ligand. Typical ligand-attached units include maleimide groups, etc. The ligand-attached unit in the present disclosure is, for example, L4.

[0051] In the present disclosure, the term "ligand-drug conjugate" generally refers to a ligand connected to a biologically active cytotoxic drug through a stable linker unit. In the present disclosure, the "ligand-drug conjugate" can be an antibody-drug conjugate (ADC), which refers to a monoclonal antibody or antibody fragment connected to a biologically active cytotoxic drug through a stable linker unit.

[0052] In the present disclosure, the term "antibody or antigen-binding fragment thereof" generally refers to an immunological binding agent extended to all antibodies from all species, including di-, tri-, and multi-meric antibodies; bispecific antibodies; chimeric antibodies; fully human antibodies; humanized antibodies; recombinant and engineered antibodies and fragments thereof. The term "antibody or fragment thereof" can refer to any antibody-like molecule having an antigen-binding region, and the term includes small molecule fragments such as Fab', Fab, F(ab')2, single domain antibodies (DABs), Fv, scFv (single chain Fv), linear antibodies, diabodies, and the like. The term "antigen-binding fragment" can refer to one or more fragments of an antibody that retain the ability to specifically bind to an antigen. For example, fragments of a full-length antibody can be utilized to perform the antigen-binding function of the antibody. Techniques for preparing and using various antibody-based constructs and fragments are well known in the art. The antibodies can include one or more of 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-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-MUC1 antibody, an anti-Lewis Y antibody, an anti-TROP2 antibody, an anti-Claudin 18.2 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, for example can be Trastuzumab (Herceptin®), Pertuzumab (Perjeta®).

[0053] In the present disclosure, the term "chimeric antibody" generally refers to an antibody in which the variable region of a murine antibody is fused with the constant region of a human antibody, and can reduce the immune response reaction induced by the murine antibody. To establish a chimeric antibody, a hybridoma secreting a murine-specific monoclonal antibody can be established, and then the variable region gene can be cloned from the murine hybridoma cell, and the constant region gene of a human antibody can be cloned as needed, and the murine variable region gene and the human constant region gene are ligated into a chimeric gene and inserted into an expression vector, and the chimeric antibody molecule can be expressed in a eukaryotic system or a prokaryotic system.

[0054] In the present disclosure, the term "humanized antibody", also known as CDR-grafted antibody, generally refers to an antibody produced by grafting murine CDR sequences into human antibody variable region framework, i.e. different types of human germline antibody framework sequences. The heterogeneity reaction induced by chimeric antibodies due to carrying a large number of murine protein components can be overcome. Such framework sequences can be obtained from public DNA databases or published references including germline antibody gene sequences. The germline DNA sequences of human heavy and light chain variable region genes can be found in the "VBase" human germline sequence database.

[0055] In the present disclosure, the term "fully human antibody", "full human antibody" or "completely human antibody", also known as "fully human monoclonal antibody", the variable region and constant region of the antibody can be both human-derived, removing immunogenicity and toxic side effects. The development of monoclonal antibodies has undergone four stages, namely: murine monoclonal antibodies, chimeric monoclonal antibodies, humanized monoclonal antibodies and fully human monoclonal antibodies. The antibody or ligand described in the present disclosure can be a fully human monoclonal antibody. The related technologies for preparing fully human antibodies can be: human hybridoma technology, EBV transformed B lymphocyte technology, phage display technology, transgenic mouse antibody preparation technology and single B cell antibody preparation technology, etc.

[0056] In the present disclosure, the term "CDR" generally refers to one of the six hypervariable regions within the variable domain of an antibody that primarily contribute to antigen binding. One of the most commonly used definitions of the six CDRs is provided by Kabat E. A. et al., (1991) Sequences of proteins of immunological interest. NIH Publication 91-3242; Chothia et al., "Canonical Structures For the Hypervariable Regions of Immunoglobulins", J. Mol. Biol. 196:901 (1987); and MacCallum et al., "Antibody-Antigen Interactions: Contact Analysis and Binding Site Topography", J. Mol. Biol. 262:732 (1996). As used in the present disclosure, the Kabat definition of CDRs can be applied to CDR1, CDR2, and CDR3 of the light chain variable domain (CDR L1, CDR L2, CDR L3 or L1, L2, L3), as well as CDR1, CDR2, and CDR3 of the heavy chain variable domain (CDR H1, CDR H2, CDR H3 or H1, H2, H3).

[0057] In the present disclosure, the term "alkyl" refers to saturated aliphatic hydrocarbon groups that are straight-chained or bear branched groups (i.e., C 1-20 alkyl groups) containing 1 to 20 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) carbon atoms, preferably alkyl groups containing 1 to 12 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12) carbon atoms (i.e., C 1-20 alkyl groups), and more preferably alkyl groups containing 1 to 6 carbon atoms (i.e., C 1-6Alkyl groups). Non-limiting examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, n-hexyl, 1-ethyl-2-methylpropyl, 1,1,2-trimethylpropyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 2,2-dimethylbutyl, 1,3-dimethylbutyl, 2-ethylbutyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2,3-dimethylbutyl, n-heptyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 2, 3-Dimethylpentyl, 2,4-Dimethylpentyl, 2,2-Dimethylpentyl, 3,3-Dimethylpentyl, 2-Ethylpentyl, 3-Ethylpentyl, n-Octyl, 2,3-Dimethylhexyl, 2,4-Dimethylhexyl, 2,5-Dimethylhexyl, 2,2-Dimethylhexyl, 3,3-Dimethylhexyl, 4,4-Dimethylhexyl, 2-Ethylhexyl, 3-Ethylhexyl, 4-Ethylhexyl, 2-Methyl-2-Ethylpentyl, 2-Methyl-3-Ethylpentyl, n-Nonyl, 2-Methyl-2-Ethylhexyl, 2-Methyl-3-Ethylhexyl, 2,2-Diethylpentyl, n-Decyl, 3,3-Diethylhexyl, 2,2-Diethylhexyl, and their various branched isomers, etc. Alkyl groups can be substituted or unsubstituted. When substituted, they can be substituted at any usable connection point. The substituents are preferably selected from one or more of deuterium, halogen, alkoxy, haloalkyl, haloalkoxy, cycloalkyloxy, heterocyclic oxy, hydroxy, hydroxyalkyl, cyano, amino, nitro, cycloalkyl, heterocyclic, aryl, and heteroaryl.

[0058] In this disclosure, the term "alkenyl" refers to an alkyl compound containing at least one carbon-carbon double bond in its molecule, wherein the alkyl group is defined as described above and has 2 to 12 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12) carbon atoms (i.e., C14, C24, C34, C44, C54, C64, C74, C84, C9 ... 2-12 Alkenyl). The alkenyl group is preferably an alkenyl group having 2 to 6 carbon atoms (i.e., C). 2-6 Alkenyl group. The alkenyl group can be substituted or unsubstituted. When substituted, the substituent is preferably selected from deuterium, alkoxy, halogen, haloalkyl, haloalkoxy, cycloalkyloxy, heterocyclic oxy, hydroxy, hydroxyalkyl, cyano, amino, nitro, cycloalkyl, heterocyclic, aryl, and heterocyclic groups.

[0059] One or more of the aryl groups.

[0060] In this disclosure, the term "haloalkyl" means an alkyl group substituted with one or more halogens, wherein the alkyl group is as defined above.

[0061] In this disclosure, the term "methylene" refers to a residue derived from a group containing one carbon atom by removing two hydrogen atoms. The methylene group can be substituted or unsubstituted, substituted or non-substituted. The term "alkylene" refers to a saturated straight-chain or branched aliphatic hydrocarbon group having two residues derived from the removal of two hydrogen atoms from the same carbon atom or two different carbon atoms of a parent alkane. It can be a straight-chain or branched group containing 1 to 20 carbon atoms, for example, containing 1 to 12 carbon atoms, such as an alkylene group containing 1 to 6 carbon atoms. Non-limiting examples of alkylene groups include, but are not limited to, methylene (-CH2-), 1,1-ethylene (-CH(CH3)-), 1,2-ethylene (-CH2CH2)-, 1,1-propylene (-CH(CH2CH3)-), 1,2-propylene (-CH2CH(CH3)-), 1,3-propylene (-CH2CH2CH2-), 1,4-butylene (-CH2CH2CH2CH2-), and 1,5-butylene (-CH2CH2CH2CH2CH2-). The alkylene group can be substituted or unsubstituted, alternative or non-alternative. For example, when substituted, the substituent can be replaced at any usable connection point. The substituent is preferably independently selected independently from one or more substituents chosen from alkyl, alkenyl, alkynyl, alkoxy, alkylthio, alkylamino, halogen, mercapto, hydroxyl, nitro, cyano, cycloalkyl, heterocyclic, aryl, heteroaryl, cycloalkoxy, heterocycloalkoxy, cycloalkylthio, heterocycloalkylthio, and oxo, for example, it can be hydrogen, protium, deuterium, tritium, halogen, -NO2, -CN, -OH, -SH, -NH2, -C(O)H, -CO2H, -C(O)C(O)H, -C(O)CH2C(O)H, -S(O)H, -S(O)2H, -C(O)NH2, -SO2NH2, -OC(O)H, -N(H)SO2H, or C 1-6 Aliphatic groups.

[0062] In this disclosure, the term "halogen" generally refers to fluorine, chlorine, bromine, or iodine, for example, fluorine or chlorine.

[0063] In this disclosure, the term "hydroxyl" refers to -OH.

[0064] In this disclosure, the term "thiol" refers to -SH.

[0065] In this disclosure, the term "amino" refers to -NH2.

[0066] In this disclosure, the term "cyano" refers to -CN.

[0067] In this disclosure, the term "nitro" refers to -NO2.

[0068] In this disclosure, the term "oxo" or "oxo" means "=O".

[0069] In this disclosure, the term "carbonyl" refers to C=O.

[0070] In this disclosure, the term "aldehyde group" refers to -C(O)H

[0071] In this disclosure, the term "carboxyl group" refers to -C(O)OH.

[0072] In this disclosure, the term "aliphatic group" generally refers to a straight-chain, branched, or cyclic hydrocarbon having 1-12 carbon atoms, which is either fully saturated or contains one or more unsaturated units, but the unsaturated units are not aromatic groups. For example, suitable aliphatic groups may include substituted or unsubstituted straight-chain, branched, or cyclic alkyl, alkenyl, alkynyl, and mixtures of these groups; such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl, or (cycloalkyl)alkenyl. For example, aliphatic groups have 1-12, 1-8, 1-6, 1-4, or 1-3 carbon atoms.

[0073] In this disclosure, the terms “optional” or “optionally” generally mean that the event or environment described below may but does not have to occur, and the description includes situations in which the event or environment occurs or does not occur. For example, “optionally alkyl-substituted heterocyclic group” means that an alkyl group may but does not have to be present, and the description can include cases where the heterocyclic group is substituted with an alkyl group and cases where the heterocyclic group is not substituted with an alkyl group.

[0074] In this disclosure, the term "substituted" generally refers to one or more hydrogen atoms in a group, for example, up to five, or for example, one to three hydrogen atoms, independently substituted by the corresponding number of substituents. Substituents are only in their possible chemical positions, and those skilled in the art can determine (by experiment or theory) possible or impossible substitutions without much effort. For example, an amino or hydroxyl group with free hydrogen may be unstable when bonded to a carbon atom with an unsaturated (e.g., alkene) bond.

[0075] In this disclosure, the term "replaced" for 0 or more (e.g., 0 or at least 1, 0 or 1, 0) methylene units generally means that when the structure contains 1 or more methylene units, the one or more methylene units may not be replaced, or may be replaced by one or more groups that are not methylene (e.g., -NHC(O)-, -C(O)NH-, -C(O)-, -OC(O)-, -C(O)O-, -NH-, -O-, -S-, -SO-, -SO2-, -PH-, -P(=O)H-, -NHSO2-, -SO2NH-, -C(=S)-, -C(=NH)-, -N=N-, -C=N-, -N=C- or -C(=N2)-).

[0076] One or more hydrogen atoms in a group, for example, up to five, or for example, one to three hydrogen atoms, are independently replaced by the corresponding number of substituents. The substituents are only in their possible chemical positions, and those skilled in the art can determine (by experiment or theory) possible or impossible substitutions without much effort. For example, an amino or hydroxyl group with free hydrogen may be unstable when bonded to a carbon atom with an unsaturated bond (such as an alkene).

[0077] In the chemical structure of the compounds disclosed herein, the bonds... This indicates that the configuration is not specified; that is, if chiral isomers exist in the chemical structure, the bond... It can be Or it may contain both configurations simultaneously. In the chemical structure of the compounds disclosed herein, the double bond... No configuration is specified, meaning it can be Z configuration, E configuration, or both configurations.

[0078] In this disclosure, the term "absent" generally indicates that there is no substituent at the position of the group, or that the two groups connected to the group are directly linked. For example, in the structure —CH2—R, when R is absent, it means that CH2 has no R substituent, i.e., the structure is —CH3; as another example, in the structure —L4—L3—L2—L1—, when L3 is absent, it means that L4 and L2 are directly linked, i.e., the structure is —L4—L2—L1—.

[0079] In this disclosure, the term "compound" generally refers to a substance having two or more different elements. For example, the compounds of this disclosure can be organic compounds, compounds with a molecular weight of less than 500, less than 1000, more than 1000, or more than 10,000 or 100,000. In this disclosure, a compound can also refer to a compound linked by chemical bonds, such as a compound in which one or more molecules with a molecular weight of less than 1000 are linked by chemical bonds to a biological macromolecule, which can be a polysaccharide, protein, nucleic acid, polypeptide, etc. For example, the compounds of this disclosure can include compounds in which a protein is linked to one or more molecules with a molecular weight of less than 1000, compounds in which a protein is linked to one or more molecules with a molecular weight of less than 10,000, or compounds in which a protein is linked to one or more molecules with a molecular weight of less than 100,000. For example, the compounds of this disclosure can be ligand-drug conjugates.

[0080] This disclosure also includes compounds identical to those described herein, but in which one or more atoms are replaced by isotopes of the present disclosure with atomic weights or mass numbers different from those commonly found in nature. Examples of isotopes that can be incorporated into compounds of the present disclosure include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, iodine, and chlorine, such as... 2 H, 3 H, 11 C 13 C 14 C 13 N、 15 N、 15 O、 17 O、 18 O、 31 P, 32 P, 35 S, 18 F, 123 I, 125 I and 36 Cl, etc.

[0081] The compounds disclosed herein may contain atomic isotopes in non-natural proportions on one or more atoms constituting the compound. For example, the compounds may be labeled with radioactive isotopes, such as tritium. 3 Deuterated drugs can be formed by replacing hydrogen with deuterium (H). The bond between deuterium and carbon is stronger than that between ordinary hydrogen and carbon. Compared with undeuterated drugs, deuterated drugs have advantages such as reduced toxicity, increased drug stability, enhanced efficacy, and prolonged drug biological half-life. All isotopic variations of the compounds disclosed herein, regardless of radioactivity, are included within the scope of this disclosure.

[0082] In addition, heavier isotopes (such as deuterium) are used. 2 H)) substitution can provide certain therapeutic advantages resulting from higher metabolic stability (e.g., increased in vivo half-life or reduced dose requirement), and may therefore be preferred in certain situations, where deuterium substitution can be partial or complete, with partial deuterium substitution referring to at least one hydrogen being replaced by at least one deuterium.

[0083] Unless otherwise specified, when a position is specifically designated as deuterium (D), that position should be understood as having a deuterium abundance of at least 1000 times greater than the natural abundance of deuterium (which is 0.015%) (i.e., at least 10% deuterium doping). The natural abundance of deuterium in the example compounds can be at least 1000 times, at least 2000 times, at least 3000 times, at least 4000 times, at least 5000 times, at least 6000 times, or higher. This disclosure also includes various deuterated forms of compounds of formula (I) (including formulas (I), (II), (III-1), and (III-2)). Each available hydrogen atom bonded to a carbon atom can be independently replaced by a deuterium atom. Those skilled in the art can synthesize deuterated forms of compounds of formula (I) (including formulas (I), (II), (III-1), and (III-2)) by referring to relevant literature. Commercially available deuterated starting materials can be used in the preparation of deuterated forms of compounds of formula (I) (including formulas (I), (II), (III-1), and (III-2)), or they can be synthesized using conventional techniques with deuterating reagents, including but not limited to deuterated boranes, trideuterated borane tetrahydrofuran solutions, deuterated lithium aluminum hydride, deuterated iodoethane, and deuterated iodomethane.

[0084] In this disclosure, the term "pharmaceutical composition" generally refers to a mixture containing one or more of the compounds described herein or their physiologically / pharmacologically acceptable salts or prodrugs, along with other chemical components, such as physiologically / pharmacologically acceptable carriers and excipients. Pharmaceutical compositions can facilitate administration to organisms, promote the absorption of the active ingredient, and thereby exert its biological activity. Conventional methods for preparing pharmaceutical compositions can be found in the Chinese Pharmacopoeia.

[0085] In this disclosure, the terms "pharmaceutically acceptable salt" or "medicinal salt" generally refer to a salt of the compounds or ligand-drug conjugates of this disclosure, or a salt of the compounds described in this disclosure, which may be safe and / or effective when used in mammals and may have the intended biological activity. The ligand-drug conjugates of this disclosure may form salts with acids. Non-limiting examples of pharmaceutically acceptable salts include: hydrochloride, hydrobromide, hydroiodide, sulfate, hydrogen sulfate, citrate, acetate, succinate, ascorbate, oxalate, nitrate, sorbate, hydrogen phosphate, dihydrogen phosphate, salicylate, hydrogen citrate, tartrate, maleate, fumarate, formate, benzoate, methanesulfonate, ethanesulfonate, benzenesulfonate, and p-toluenesulfonate.

[0086] In this disclosure, the terms "solvent" or "solvent compound" generally refer to a pharmaceutically usable solvate formed by the ligand-drug conjugate of this disclosure with one or more solvent molecules, non-limiting examples of which include water, ethanol, acetonitrile, isopropanol, DMSO, and ethyl acetate.

[0087] The term "drug loading" typically refers to the average number of cytotoxic drugs loaded onto each ligand, and can also be expressed as the ratio of cytotoxic drug to antibody. The range of cytotoxic drug loading can be 0-12 cytotoxic drugs per ligand (Ab), for example, 1-10 cytotoxic drugs. In embodiments of this disclosure, drug loading is expressed as N. a Examples can be the average of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. The drug loading of each ADC molecule after the coupling reaction can be identified using conventional methods such as UV / visible spectroscopy, mass spectrometry, ELISA, and HPLC characterization.

[0088] The pharmaceutical composition may be in the form of a sterile injectable aqueous or oil suspension for intramuscular and subcutaneous administration. This suspension may be formulated using suitable dispersants or wetting agents and suspending agents as described above, according to known techniques. The sterile injectable formulation may also be a sterile injectable solution or suspension prepared in a non-toxic, parenteral-acceptable diluent or solvent, such as a solution prepared in 1,3-butanediol. Furthermore, a sterile fixative oil may be conveniently used as a solvent or suspension medium. For example, any blended fixative oil, including synthetic mono- or diglycerides of glycerol, may be used. Additionally, fatty acids such as oleic acid may also be used to prepare the injectable formulation.

[0089] In this disclosure, the term "comprising" generally means including the expressly specified features, but does not exclude other elements. The terms "above" and "below" generally mean including the stated number.

[0090] In this disclosure, the singular forms “a”, “an”, and “the” include plural objects, and vice versa, unless the context clearly indicates otherwise.

[0091] In this disclosure, the term "about" generally refers to a variation within 10% (i.e., ±10%) above or below a specified value, for example, a variation within 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10% above or below a specified value. For parameters such as pH, concentration, and temperature, it indicates that the parameter can vary within ±10%, and sometimes more preferably within ±5%. As those skilled in the art will understand, when a parameter is not critical, figures are generally given for illustrative purposes only and not as limitations.

[0092] The compounds disclosed herein

[0093] The first aspect of this disclosure relates to a ligand-drug conjugate or a pharmaceutically acceptable salt thereof, wherein the ligand-drug conjugate has the structure shown in formula (I): mAb—(L—D)z Formula (I);

[0094] Where mAb is a ligand that binds to the target site;

[0095] z is the average conjugation ratio of the drug ligands, and z is selected from an integer or decimal of about 1 to about 16;

[0096] L is a connection unit with the following structure: —L4—L3—L2—L1—; where,

[0097] The L4 is Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, position 1 is connected to the ligand, and position 2 is connected to L3; R X Selected from C 1-6 Alkyl and C 3-6 cycloalkyl, the C 1-6 Alkyl and C 3-6 The cycloalkyl group is optionally surrounded by one or more radicals selected from halogen, cyano, hydroxyl, C 1-6 Alkyl and C 3-6 Substituents of cycloalkyl groups;

[0098] The L3 is selected from Where s is an integer from 1 to 30, with 1 bit connected to L4 and 2 bits connected to L2;

[0099] The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by 1, 2, or 3 carbon atoms. 1-6 Alkyl groups are substituted;

[0100] The L1 is absent or is a self-destructing unit;

[0101] D is a drug with the structure shown in formula (II):

[0102] The wavy line represents the key connecting L and D;

[0103] R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl and C 1-6 Alkoxy;

[0104] W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups.

[0105] In some embodiments of the ligand-drug conjugate shown in formula (I), in formula (II), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-33 Halogenated alkyl groups and C 1-3 Alkyl group. Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy. More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine.

[0106] In some embodiments of the ligand-drug conjugate shown in formula (I), in formula (II), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-3 Halogenated alkyl groups and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen. Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 Both are hydrogen. Preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 Both are hydrogen. More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen.

[0107] In some embodiments of the ligand-drug conjugate shown in formula (I), in formula (II), R 1 R 2 and R 3 Both are hydrogen.

[0108] In some embodiments of the ligand-drug conjugate shown in formula (I), in formula (II), R 1 It is fluorine, R 2 and R 3 Both are hydrogen.

[0109] In some embodiments of the ligand-drug conjugate shown in formula (I), W in formula (II) is... Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms. More preferably, R... 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl. More preferably, R 4 and R 5 All are methyl. Or, more preferably, R 4 and R 5 All are ethyl. Or, more preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0110] In some embodiments of the ligand-drug conjugate shown in formula (I), W in formula (II) is... Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3-6 The cycloalkyl group is substituted. Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group. More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms. More preferably, R 6 and R 7 All are methyl. Or, more preferably, R 6 and R 7 All are ethyl. Or, more preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0111] In some embodiments of the ligand-drug conjugate shown in formula (I), W in formula (II) is... Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C3-6 The cycloalkyl group is substituted. Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. More preferably, R... 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl, and methoxy. More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups.

[0112] In some embodiments of the ligand-drug conjugate shown in formula (I), the L4 is selected from... Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, position 1 is connected to the ligand, and position 2 is connected to L3; R X Selected from C 1-3 Alkyl and C 3-5 cycloalkyl, the C 1-3 Alkyl and C 3-5 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, and C. 1-3 The alkyl group is substituted. In some embodiments, m1 is 1, 2, 3, 4, or 5. Preferably, m1 is an integer from 1 to 3. More preferably, m1 is 2. In some embodiments, m2 is 0, 1, 2, 3, 4, or 5. Preferably, m2 is an integer from 0 to 3. More preferably, m2 is 0. More preferably, m2 is 2. In some embodiments, preferably, R X C 1-3 Alkyl; more preferably, R X It is methyl or ethyl; more preferably, R XIt is methyl. In some embodiments, preferably, R X C 3-5 Cycloalkyl; more preferably, R X It is cyclopropyl.

[0113] In some embodiments of the ligand-drug conjugate shown in formula (I), preferably, L4 is

[0114] In some embodiments of the ligand-drug conjugate shown in formula (I), preferably, L4 is

[0115] In some embodiments of the ligand-drug conjugate shown in formula (I), preferably, L4 is

[0116] In some embodiments of the ligand-drug conjugate shown in formula (I), the L3 is selected from... Wherein, s is an integer from 1 to 24, with one bit connected to L4 and two bits connected to L2. Preferably, s is an integer from 1 to 20. For example, s is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. More preferably, s is an integer from 2 to 12. More preferably, s is an integer from 2 to 8. In some embodiments, s is 2. In some embodiments, s is 4. In some embodiments, s is 8.

[0117] In some embodiments of the ligand-drug conjugate shown in formula (I), L2 is an amino acid or a peptide consisting of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or stereoisomers thereof; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; preferably, when the amino acid residue is Lys, the side chain amino group of Lys is optionally replaced by one or two C atoms. 1-3 Alkyl groups are substituted; more preferably, when the amino acid residue is Lys, the side chain amino group of Lys is substituted with two methyl groups, two ethyl groups, or two n-propyl groups.

[0118] In some embodiments of the ligand-drug conjugate shown in formula (I), preferably, the L2 is selected from -Lys-, -Ala-Lys-, -Gly-Lys-, -Lys-Gly-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Lys-Val-, -Ala-Ala-Asn-, -Ala-Ala-Asn-, -Ala-Ala-Asp-, -Ala-Lys-Gly-, -(D-Val -Leu-Lys-, -Glu-Gly-Lys-, -Gly-Lys-Gly-, -Lys-Ala-Asn-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Val-Ala-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, and -Val-Lys-Gly-Gly-. Wherein, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted. More preferably, the L2 is selected from -Val-Ala-, -Glu-Gly-Lys-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, or -Gly-Gly-Val-Ala-. Wherein, the side-chain amino group of Lys is optionally replaced by one or two C atoms. 1-6 Alkyl groups are substituted. More preferably, the L2 is -Gly-Gly-Phe-Gly-. Or, more preferably, the L2 is -Glu-Gly-Lys-, wherein the side chain amino group of Lys is substituted with two methyl groups. Or, more preferably, the L2 is -Glu-Gly-Cit-Gly-.

[0119] In some embodiments of the ligand-drug conjugate shown in formula (I), preferably, L1 is absent.

[0120] In some embodiments of the ligand-drug conjugate shown in formula (I), preferably, L1 is selected from:

[0121] Of these, bit 1 is connected to L2, and bit 2 is connected to D.

[0122] In some embodiments of the ligand-drug conjugate shown in formula (I), L is selected from the structures in Table 1 below:

[0123] Table 1

[0124] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb may be an antibody or its antigen-binding fragment.

[0125] Preferably, the mAb is selected from the group consisting of chimeric antibodies, humanized antibodies, and fully human antibodies.

[0126] Preferably, the antigen-binding fragment is selected from the group consisting of: Fab′, Fab, F(ab′)2, single-domain antibodies (DABs), Fv, scFv (single-chain Fv).

[0127] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb may be an antibody or its antigen-binding fragment targeting the following targets: 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, 0772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79 b, CCL5, CCR5, CCR7, CD11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD40, CD 45, CD45(PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.2. c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EG FRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRα, GD2, GEDA, G PC-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra , IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP 14, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC 39A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, short proteoglycans, mesothelin, endothelial peptide receptors, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin α4β7, integrin α5β6, trophoblast cell glycoproteins, and tissue factor.

[0128] In some embodiments of the ligand-drug conjugate shown in Formula (I), the mAb is an antibody or its antigen-binding fragment targeting the following targets: HER2, HER3, B7H3, TROP2, Claudin 18.2, CD30, CD33, CD70, EGFR, and FRα.

[0129] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-Trop-2 antibody or an antigen-binding fragment thereof; preferably, the mAb is datopotamab, sacituzumab or an antigen-binding fragment thereof.

[0130] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-Her 2 antibody or an antigen-binding fragment thereof; preferably, the mAb is anbenitamab, coprelotamab, disitamab, gancotamab, margetuximab, pertuzumab, timigutuzumab, zanidatamab, Trastuzumab, Pertuzumab or an antigen-binding fragment thereof.

[0131] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-Her3 antibody or an antigen-binding fragment thereof; preferably, the mAb is a barecetamab, duligotuzumab, elgemtumab, istiratumab, lumretuzumab, patritumab, seribantumab, zenocutuzumab, 202-2-1 antibody or an antigen-binding fragment thereof.

[0132] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-EGFR antibody or an antigen-binding fragment thereof; preferably, the mAb is demupitamab, depatuxizumab, futuximab, imgatuzumab, lapatuximab, losatuxizumab, matuzumab, modotuximab, necitumumab, nimotuzumab, panitumumab, pimurutamab, serclutamab, tomuzotuximab, zalutumumab, Cetuximab or an antigen-binding fragment thereof.

[0133] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-B7H3 antibody or its antigen-binding fragment; preferably, the mAb is an antibody of 1D1, 1D1-01, 2E3, 2E3-02, enoblituzumab, mirzotamab, omburtamab or its antigen-binding fragment.

[0134] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-LIV1 antibody or an antigen-binding fragment thereof; preferably, the mAb is Ladiratuzumab or an antigen-binding fragment thereof.

[0135] In some embodiments of the ligand-drug conjugate shown in formula (I), the mAb is an anti-FRα antibody or its antigen-binding fragment; preferably, the mAb is v30384 or its antigen-binding fragment.

[0136] In some embodiments of the ligand-drug conjugate shown in formula (I), the average drug-ligand conjugation ratio z is an integer or fraction from about 1 to about 10. Preferably, the average drug-ligand conjugation ratio z is an integer or fraction from about 3 to about 8. Preferably, the average drug-ligand conjugation ratio z is an integer or fraction from about 1 to about 2, about 2 to about 3, about 3 to about 4, about 4 to about 5, about 5 to about 6, about 6 to about 7, about 7 to about 8, about 8 to about 9, or about 9 to about 10. Preferably, the average drug-ligand conjugation ratio z is about 1, about 2, about 3, about 4, about 5, about 6, about 7, or about 8.

[0137] In some implementations, the ligand-drug conjugate represented by formula (I) is selected from the structures in Table 2 below:

[0138] Table 2

[0139] In some implementations, the ligand-drug conjugate represented by formula (I) is selected from the structures in Table 3 below:

[0140] Table 3

[0141] In this context, TZB or tzb represents trastuzumab, and v30384 represents anti-FRα antibody.

[0142] In some embodiments, the ligand-drug conjugate represented by formula (I) is substituted with an isotope. Preferably, in some embodiments, the isotope substitution is deuterium substitution.

[0143] The second aspect of this disclosure relates to a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound has a structure represented by formula (IA): L-D Formula (IA);

[0144] Wherein, L is a connecting unit with the following structure: L4'—L3—L2—L1—; where,

[0145] The L4' is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 1 to 5, and 2 bits are connected to L3; R X Selected from C 1-6 Alkyl and C 3-6 cycloalkyl, the C 1-6 Alkyl and C 3-6 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, C 1-6 Alkyl and C 3-6 Substituents of cycloalkyl groups; G1 and G2 are leaving groups;

[0146] The L3 is selected from Where s is an integer from 1 to 30, with 1 bit connected to L4' and 2 bits connected to L2;

[0147] The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by 1, 2, or 3 carbon atoms. 1-6 Alkyl groups are substituted;

[0148] The L1 is absent or is a self-destructing unit;

[0149] D is a drug with the structure shown in formula (II):

[0150] in,

[0151] The wavy line represents the key connecting L and D;

[0152] R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl groups and C1-6 Alkoxy;

[0153] W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups.

[0154] In some embodiments of the compound of formula (IA), in formula (II), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-3 Halogenated alkyl groups and C 1-3 Alkyl group. Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy. More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine.

[0155] In some embodiments of the compound of formula (IA), in formula (II), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-33 Halogenated alkyl groups and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen. Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 Both are hydrogen. Preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 Both are hydrogen. More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen.

[0156] In some embodiments of the compound of formula (IA), in formula (II), R 1 R 2 and R 3 Both are hydrogen.

[0157] In some embodiments of the compound of formula (IA), in formula (II), R 1 It is fluorine, R 2 and R 3 Both are hydrogen.

[0158] In some embodiments of the compound of formula (IA), W in formula (II) is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1- 3 heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group. More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms. More preferably, R 4 and R 5 All are methyl. Or, more preferably, R 4 and R 5 All are ethyl. Or, more preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0159] In some embodiments of the compound of formula (IA), W in formula (II) is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3-6 The cycloalkyl group is substituted. Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group. More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms. More preferably, R 6 and R 7 All are methyl. Or, more preferably, R 6 and R 7 All are ethyl. Or, more preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0160] In some embodiments of the compound of formula (IA), W in formula (II) is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C3-6 The cycloalkyl group is substituted. Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. More preferably, R... 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl, and methoxy. More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups.

[0161] In some embodiments of the compound of formula (IA), G1 and G2 are each independently selected from halogen, sulfonyl, sulfonate, nitro, and optionally substituted with one or more of the following groups: alkyl sulfide, aryl sulfide, heteroaryl sulfide, alkyl sulfoxide, aryl sulfoxide, heteroaryl sulfoxide, alkyl sulfonyl, aryl sulfonyl, heteroaryl sulfonyl, wherein each substituent is independently selected from hydrogen, deuterium, halogen, CN, nitro, C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Alkyl carbonyl, halogenated C 1-6Alkyl carbonyl, 5-10 membered heterocyclic carbonyl, 6-10 membered aryl, 5-16 membered heteroaryl, 6-10 membered aryl carbonyl, and 5-16 membered heteroaryl carbonyl. Preferably, G1 and G2 are each independently selected from F, Cl, Br, I, OMs (methanesulfonate group), Ots (p-toluenesulfonate group), OTf (trifluoromethanesulfonate group), methanesulfonyl, ethanesulfonyl, p-toluenesulfonyl, naphthalenesulfonyl, aryl thioether group optionally substituted with one or more substituents, and heteroaryl thioether group optionally substituted with one or more substituents. More preferably, G1 and G2 are each independently selected from F, Cl, Br, OMs, OTs, methanesulfonyl, p-toluenesulfonyl, and phenyl thioether group optionally substituted with one or more substituents. More preferably, G1 and G2 are each independently selected from Cl, methanesulfonyl, and phenyl thioether group optionally substituted with one or more substituents.

[0162] In some embodiments of the compound of formula (IA), preferably, G1 is

[0163] In some embodiments of the compound of formula (IA), preferably, G2 is Cl or methanesulfonyl.

[0164] In some embodiments of the compound of formula (IA), the L4' is selected from... Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, and 2 bits are connected to L3; R X Selected from C 1-3 Alkyl and C 3-5 cycloalkyl, the C 1-3 Alkyl and C 3-5 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, and C. 1-3 The alkyl group is substituted. In some embodiments, m1 is 1, 2, 3, 4, or 5. Preferably, m1 is an integer from 1 to 3. More preferably, m1 is 2. In some embodiments, m2 is 0, 1, 2, 3, 4, or 5. Preferably, m2 is an integer from 0 to 3. More preferably, m2 is 0. More preferably, m2 is 2. In some embodiments, preferably, R X C 1-3 Alkyl; more preferably, R X It is methyl or ethyl; more preferably, R X It is methyl. In some embodiments, preferably, R X C 3-5 Cycloalkyl; more preferably, R X It is cyclopropyl.

[0165] In some embodiments of the compound of formula (IA), preferably, L4' is

[0166] In some embodiments of the compound of formula (IA), preferably, L4' is

[0167] In some embodiments of the compound of formula (IA), preferably, L4' is

[0168] In some embodiments of the compound of formula (IA), the L3 is selected from... Where s is an integer from 1 to 24, with one bit connected to L4 and two bits connected to L2. Preferably, s is an integer from 1 to 20. For example, s is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. More preferably, s is an integer from 2 to 12. More preferably, s is an integer from 2 to 8. In some embodiments, s is 2. In some embodiments, s is 4. In some embodiments, s is 8.

[0169] In some embodiments of the compound of formula (IA), L2 is an amino acid or a peptide consisting of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or stereoisomers thereof; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; preferably, when the amino acid residue is Lys, the side chain amino group of Lys is optionally replaced by one or two C atoms. 1-3 Alkyl groups are substituted; more preferably, when the amino acid residue is Lys, the side chain amino group of Lys is substituted with two methyl groups, two ethyl groups, or two n-propyl groups.

[0170] In some embodiments of the compound of formula (IA), preferably, the L2 is selected from -Lys-, -Ala-Lys-, -Gly-Lys-, -Lys-Gly-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Lys-Val-, -Ala-Ala-Asn-, -Ala-Ala-Asn-, -Ala-Ala-Asp-, -Ala-Lys-Gly-, -(D-Val)-Le u-Lys-, -Glu-Gly-Lys-, -Gly-Lys-Gly-, -Lys-Ala-Asn-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Val-Ala-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, and -Val-Lys-Gly-Gly-. In these sequences, the side chain amino group of Lys is optionally surrounded by one or two carbon atoms. 1-6 Alkyl groups are substituted. More preferably, the L2 is selected from -Val-Ala-, -Glu-Gly-Lys-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, or -Gly-Gly-Val-Ala-. Wherein, the side-chain amino group of Lys is optionally replaced by one or two C atoms. 1-6 Alkyl groups are substituted. More preferably, the L2 is -Gly-Gly-Phe-Gly-. Or, more preferably, the L2 is -Glu-Gly-Lys-, wherein the side chain amino group of Lys is substituted with two methyl groups. Or, more preferably, the L2 is -Glu-Gly-Cit-Gly-.

[0171] In some embodiments of the compound of formula (IA), preferably, L1 is absent.

[0172] In some embodiments of the compound of formula (IA), preferably, the L1 is selected from: In this configuration, position 1 is connected to L2, and position 2 is connected to D. In some embodiments of the compound of formula (IA), the compound of formula (IA) is selected from the structures listed in Table 4 below:

[0173] Table 4

[0174] In some embodiments, the above-mentioned compound is substituted with an isotope. Preferably, in some embodiments, the isotope substitution is deuterium substitution.

[0175] A third aspect of this disclosure relates to a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound has the structure shown in formula (IIA):

[0176] Among them, R 1 R 2 R 3 And W is as defined in equation (I).

[0177] R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl groups and C 1-6 Alkoxy;

[0178] W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups.

[0179] In some embodiments of the compound of formula (IIA), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-3 Halogenated alkyl groups and C 1-3 Alkyl group. Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy. More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine.

[0180] In some embodiments of the compound of formula (IIA), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-33 Halogenated alkyl groups and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen. Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 Both are hydrogen. Preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 Both are hydrogen. More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen.

[0181] In some embodiments of the compound of formula (IIA), R 1 R 2 and R 3 Both are hydrogen.

[0182] In some embodiments of the compound of formula (IIA), R 1 It is fluorine, R 2 and R 3 Both are hydrogen.

[0183] In some embodiments of the compound of formula (IIA), W is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group. More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms. More preferably, R 4 and R 5 All are methyl. Or, more preferably, R 4 and R 5 All are ethyl. Or, more preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0184] In some embodiments of the compound of formula (IIA), W is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3-6 The cycloalkyl group is substituted. Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group. More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms. More preferably, R 6 and R 7 All are methyl. Or, more preferably, R 6 and R 7 All are ethyl. Or, more preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0185] In some embodiments of the compound of formula (IIA), W is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 The cycloalkyl group is substituted. More preferably, R... 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl, and methoxy. More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups.

[0186] In some embodiments of the compound of formula (IIA), the compound is selected from the structures in Table 5A below:

[0187] Table 5A

[0188] In some embodiments, the above-mentioned compound is substituted with an isotope. Preferably, in some embodiments, the isotope substitution is deuterium substitution.

[0189] The camptothecin-like compounds disclosed in this disclosure possess excellent antitumor activity. This disclosure uses these camptothecin-like compounds as a payload to conjugate antibodies that bind to tumor cell surface antigens. This fully utilizes the specificity of antibody binding to tumor cell surface antigens and the antitumor activity and excellent safety of these compounds, potentially overcoming the problems of insufficient antitumor activity, drug resistance, and excessive toxic side effects of existing ADC drugs.

[0190] Preparation method

[0191] The fourth aspect of this disclosure relates to a method for preparing a compound of formula (I) of this disclosure or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, comprising contacting a ligand mAb with a structure represented by formula (IA) of this disclosure.

[0192] Composition

[0193] This disclosure relates in a fifth aspect to a pharmaceutical composition comprising, for example, a ligand-drug conjugate of formula (I) or a pharmaceutically acceptable salt thereof, or a compound of formula (IIA) or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. The carrier may be selected from the group consisting of fillers (diluents), binders, wetting agents, disintegrants, and excipients. Depending on the method of administration, the composition may contain 0.1 to 99% by weight of the active compound.

[0194] Pharmaceutical compositions containing active ingredients may be in oral forms, such as tablets, sugar lozenges, tablets, aqueous or oil suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups. Oral compositions may be prepared according to any method known in the art for preparing pharmaceutical compositions, and may contain binders, fillers, lubricants, disintegrants, or pharmaceutically acceptable wetting agents, and may also contain one or more ingredients selected from the group consisting of sweeteners, flavoring agents, coloring agents, and preservatives.

[0195] Aqueous suspensions may contain active substances and excipients suitable for mixing. Aqueous suspensions may also contain one or more preservatives, such as one or more colorants, one or more flavoring agents, and one or more sweeteners. Oil suspensions can be prepared by suspending the active ingredient in vegetable oil. Oil suspensions may contain thickeners. The aforementioned sweeteners and flavoring agents may also be added.

[0196] The pharmaceutical composition may also provide the active ingredient as a dispersible powder or granules for preparing an aqueous suspension, by adding one or more of a water-mixing dispersant, wetting agent, suspending agent, or preservative. Other excipients such as sweeteners, flavoring agents, and coloring agents may also be added. These compositions are preserved by adding antioxidants such as ascorbic acid. The pharmaceutical compositions of this application may also be in the form of an oil-in-water emulsion.

[0197] The pharmaceutical composition may be in the form of a sterile injectable aqueous solution. Acceptable solvents or media that can be used include water, Ringer's solution, and isotonic sodium chloride solution. The sterile injectable formulation may be a sterile injectable oil-in-water microemulsion in which the active ingredient is dissolved in the oil phase. For example, the active ingredient may be dissolved in a mixture of soybean oil and lecithin. The oil solution may then be treated with a mixture of water and glycerol to form a microemulsion. The injection solution or microemulsion may be injected into the patient's bloodstream via local large-volume injection. Alternatively, the solution and microemulsion may be administered in a manner that maintains a constant circulating concentration of the compound of this application. To maintain such a constant concentration, a continuous intravenous delivery device may be used. For example, the device may be a Deltec CADD-PLUS™ 5400 intravenous infusion pump.

[0198] The pharmaceutical composition may be in the form of a sterile injectable aqueous or oil suspension for intramuscular and subcutaneous administration. This suspension may be formulated using suitable dispersants or wetting agents and suspending agents described above, according to known techniques. The sterile injectable formulation may also be a sterile injectable solution or suspension prepared in a parenteral-acceptable, non-toxic diluent or solvent. Alternatively, a sterile fixative oil may be conveniently used as a solvent or suspension medium.

[0199] The disclosed compounds can be administered in suppository form for rectal administration. These pharmaceutical compositions can be prepared by mixing the drug with a suitable, non-irritating excipient that is solid at normal temperatures but liquid in the rectum, and thus dissolves in the rectum to release the drug. Such substances include cocoa butter, glycerin gelatin, hydrogenated vegetable oils, polyethylene glycol of various molecular weights, and mixtures of fatty acid esters of polyethylene glycol.

[0200] As is well known to those skilled in the art, the dosage of a drug depends on a variety of factors, including but not limited to: the activity of the specific compound used, the patient's age, the patient's weight, the patient's health status, the patient's behavior, the patient's diet, the timing of administration, the route of administration, the rate of excretion, and the combination of drugs; in addition, the optimal mode of treatment, such as the treatment regimen, the compound described in this disclosure or its tautomers, mesosomes, racemates, enantiomers, diastereomers, or mixtures thereof, or pharmaceutically acceptable salts thereof, and / or the daily dosage or type of pharmaceutically acceptable salt of the compound or its tautomers, mesosomes, racemates, enantiomers, diastereomers, or mixtures thereof, or pharmaceutically acceptable salts thereof, can be verified based on conventional treatment protocols.

[0201] Treatment and / or prevention

[0202] The sixth aspect of this disclosure relates to the use of a ligand-drug conjugate containing, for example, a ligand-drug conjugate of formula (I) of this disclosure or a pharmaceutically acceptable salt thereof, or a compound of formula (IIA) or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and / or a pharmaceutical composition of this disclosure in the preparation of a medicament for treating and / or preventing tumors.

[0203] This disclosure also provides a method of treating and / or preventing tumors, comprising administering to a subject in need the ligand-drug conjugate described herein or a pharmaceutically acceptable salt thereof, or the compound thereof or in the form of its tautomers, mesosomes, racemates, enantiomers, diastereomers, or mixtures thereof, or a pharmaceutically acceptable salt thereof, and / or a pharmaceutical composition thereof.

[0204] This disclosure also provides a ligand-drug conjugate of the present disclosure or a pharmaceutically acceptable salt thereof, or the compound thereof or in the form of its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and / or a pharmaceutical composition thereof, for the treatment and / or prevention of tumors.

[0205] In some embodiments, the tumor may be selected from tumors associated with the expression of the following groups: 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, O772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79b, CCL5, CCR5. , CCR7, CD11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD40, CD45, CD 45(PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.2. c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EG FRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRα, GD2, GEDA, G PC-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra , IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP 14, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC 39A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, short proteoglycans, mesothelin, endothelial peptide receptors, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin α4β7, integrin α5β6, trophoblast cell glycoproteins, and tissue factor.

[0206] In some embodiments, the tumor may be selected from tumors associated with the expression of the following groups: HER2, HER3, B7H3, TROP2, LIV-1, Claudin 18.2, CD30, CD33, CD70, EGFR, or FRα.

[0207] In some implementations, the tumor is a tumor associated with HER2 expression.

[0208] In some implementations, the tumor is a tumor associated with HER3 expression.

[0209] In some implementations, the tumor is a tumor associated with B7H3 expression.

[0210] In some implementations, the tumor is a tumor associated with TROP2 expression.

[0211] In some implementations, the tumor is a tumor associated with LIV-1 expression.

[0212] In some implementations, the tumor is a tumor associated with Claudin 18.2 expression.

[0213] In some implementations, the tumor is a tumor associated with CD30 expression.

[0214] In some implementations, the tumor is a tumor associated with CD33 expression.

[0215] In some implementations, the tumor is a tumor associated with CD70 expression.

[0216] In some implementations, the tumor is a tumor associated with EGFR expression.

[0217] In some implementations, the tumor is a tumor associated with FRα expression.

[0218] In some embodiments, the tumor may be selected from the group consisting of: lung cancer, breast cancer, rectal cancer, colon cancer, esophageal cancer, gastric cancer, liver cancer, gallbladder cancer, bile duct cancer, kidney cancer, bladder cancer, urothelial carcinoma, head and neck cancer, nasopharyngeal carcinoma, prostate cancer, cervical cancer, endometrial cancer, ovarian cancer, pancreatic cancer, melanoma, bone cancer, mesothelioma, gastrointestinal stromal tumor, sarcoma, glioma, thyroid cancer, salivary gland tumor, glioblastoma, neuroblastoma, gastric mucinoma, lymphoma, leukemia, plasmacytoma, sinoatrial node cell tumor, giant cell tumor of the tendon sheath, brain cancer, squamous cell carcinoma, epidermal carcinoma, and non-Hodgkin's lymphoma; more preferably, the cancer is selected from breast cancer, prostate cancer, lung cancer, pancreatic cancer, ovarian cancer, cervical cancer, endometrial cancer, bladder cancer, glioma, malignant lymphoma, liver cancer, and leukemia;

[0219] Preferably, the cancer is pancreatic cancer, colorectal cancer, lung cancer, stomach cancer, or breast cancer.

[0220] The compounds described in this application can possess inhibitory activity against the in vitro proliferation of tumor cells. This inhibitory activity can be defined as a decrease in the proliferation capacity of tumor cells by more than 1%, 2%, 4%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% when the compound is added to a culture medium containing tumor cells, compared to the addition of a negative control or control drug. For example, the inhibitory activity can be defined as an effect on the IC50 of tumor cells. 50 The value (nM) can be below 10000, below 5000, below 4000, below 3000, below 2000, below 1000, below 500, below 400, below 300, below 200, below 150, below 120, below 110, below 100, below 99, below 98, below 97, below 95, below 90, below 80, below 75, below 70, below 65, below 62, below 60, below 50, below 40, below 30, below 25, below 23, below 22, below 20, below 19, below 18, below 18.5, below 17, below 15, below 12, below 10, below 9. Below 8.5, below 7, below 6.7, below 6, below 5.9, below 5.5, below 5.0, below 4.8, below 4.5, below 4.4, below 4, below 3.5, below 3, below 2.5, below 2, below 1.5, below 1.0, below 0.5, below 0.3, below 0.29, below 0.25, below 0.21, below 0.20, below 0.18, below 0.17, below 0.15, below 0.12, below 0.10, below 0.09, below 0.08, below 0.07, below 0.06, below 0.05, below 0.04, below 0.03, below 0.02, or below 0.01. For example, the tumor cells may include, but are not limited to, solid tumor cells, such as gastric cancer cells, lung cancer cells, or breast cancer cells.

[0221] The compounds described in this application may possess targeted inhibitory properties. This targeted inhibitory property can be defined as the reduction in the proliferation capacity of tumor cells highly expressing a specific target by more than 1%, 2%, 4%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% when the compound is added to a culture medium containing a negative control or control drug, compared to the addition of a negative control or control drug. For example, the targeted inhibitory property can be defined as an IC50 effect on tumor cells highly expressing a specific target. 50The value (nM) can be below 10000, below 5000, below 4000, below 3000, below 2000, below 1000, below 500, below 400, below 300, below 200, below 185, below 150, below 120, below 110, below 100, below 99, below 98, below 97, below 95, below 91, below 80, below 74, below 70, below 65, below 62, below 60, below 50, below 40, below 30, below 25, below 23, below 22, below 20, below 19, below 18, below 18.5, below 17, below 15, below 12, below 10, 9 Below, 8.5, below 7, below 6.7, below 6, below 5.9, below 5.5, below 5.0, below 4.8, below 4.5, below 4.4, below 4, below 3.5, below 3, below 2.5, below 2, below 1.5, below 1.0, below 0.5, below 0.3, below 0.29, below 0.25, below 0.21, below 0.20, below 0.18, below 0.17, below 0.15, below 0.12, below 0.10, below 0.09, below 0.08, below 0.07, below 0.06, below 0.05, below 0.04, below 0.03, below 0.02, or below 0.01. For example, tumor cells highly expressing the specific target may include, but are not limited to, solid tumor cells, such as, gastric cancer cells or breast cancer cells.

[0222] The compounds described in this application may possess plasma stability. This plasma stability means that when the compound is added to plasma, the release rate of the cytotoxic drug released by the compound does not exceed 50%, 40%, 30%, 20%, 10%, 7%, 5%, 4%, 3%, 2%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.1%.

[0223] The compounds described in this application can have an in vivo tumor-suppressing effect. This tumor-suppressing effect can be demonstrated by the following: when the compounds of this application are administered to animals, compared to the addition of a negative control or control drug, the tumor volume of the animals is reduced by more than 1%, 2%, 4%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 40%, 50%, 55%, 60%, 70%, 73%, or 75% at 1, 3, 5, 7, 14, 20, 21, or 30 days, respectively. The tumor volume of the animal decreased by more than 1.1 times, 1.3 times, 1.5 times, 2 times, 3 times, 5 times, 10 times, 20 times, 22 times, 30 times, 50 times, 100 times, 500 times, 1000 times, or 1500 times or more at 1 day, 3 days, 5 days, 7 days, 14 days, 20 days, 21 days, or 30 days, or compared to the administration of a negative control or control drug. The animal may include, but is not limited to, mammals, such as cats, dogs, horses, pigs, cows, sheep, rabbits, mice, rats, monkeys, or humans. The administration may include, but is not limited to, oral administration, intravenous injection, intravenous infusion, intraperitoneal injection, or local administration.

[0224] The compounds described in this application may exhibit a bystander effect. This bystander effect can mean that the compounds of this application have no significant inhibitory effect on the cell proliferation of tumor cells with low expression of a specific target, but in co-culture of tumor cells with low expression of a specific target and tumor cells with high expression of a specific target, the compounds of this application can simultaneously inhibit the cell proliferation of both types of tumor cells. For example, in co-culture of tumor cells with low expression of a specific target and tumor cells with high expression of a specific target, the inhibitory activity can be defined as an IC50 value against tumor cells with low expression of a specific target. 50The value (nM) can be below 10000, below 5000, below 4000, below 3000, below 2000, below 1000, below 500, below 400, below 300, below 200, below 185, below 150, below 120, below 110, below 100, below 99, below 98, below 97, below 95, below 91, below 80, below 74, below 70, below 65, below 62, below 60, below 50, below 40, below 30, below 25, below 23, below 22, below 20, below 19, below 18, below 18.5, below 17, below 15, below 12, below 10, 9 Below, below 8.5, below 7, below 6.7, below 6, below 5.9, below 5.5, below 5.0, below 4.8, below 4.5, below 4.4, below 4, below 3.5, below 3, below 2.5, below 2, below 1.5, below 1.0, below 0.5, below 0.3, below 0.29, below 0.25, below 0.21, below 0.20, below 0.18, below 0.17, below 0.15, below 0.12, below 0.10, below 0.09, below 0.08, below 0.07, below 0.06, below 0.05, below 0.04, below 0.03, below 0.02, or below 0.01. Compared to tumor cells that highly express a specific target, tumor cells with low expression of that target may exhibit a reduction in the expression of that specific target by more than 1%, 2%, 4%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%. For example, tumor cells with high expression of the specific target may include, but are not limited to, solid tumor cells, such as gastric cancer cells or breast cancer cells, including but not limited to BT474 cells, T47D cells, or MCF7-LIV1 cells. Similarly, tumor cells with low expression of the specific target may include, but are not limited to, solid tumor cells, such as breast cancer cells, including but not limited to HCC1187 cells.

[0225] The compounds described in this application may possess antitransporter transport capabilities. This antitransporter capability can be defined as a reduction in the efflux ratio of the compound compared to a standard of the transport substrate, which is more than 1%, 2%, 4%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%. For example, the efflux ratio test can be a method commonly used by those skilled in the art, or it can be described in the embodiments of this application.

[0226] The compounds described in this application may possess in vivo tumor-targeting capability. This in vivo targeting capability can refer to the distribution of the labeled compound in the tumor tissue of an animal, compared to other tissues and organs, being increased by more than 1%, 2%, 4%, 5%, 8%, 10%, 15%, 18%, 20%, 25%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%, or by more than 1.1 times, 1.3 times, 1.5 times, 2 times, 3 times, 5 times, 10 times, 20 times, 22 times, 30 times, 50 times, 100 times, 500 times, 1000 times, or 1500 times. The signaling substance may be a radioactive substance, and for example, the signaling substance includes, but is not limited to, radioactive substances. 125 I. The animal may include, but is not limited to, mammals, such as cats, dogs, horses, pigs, cows, sheep, rabbits, mice, rats, monkeys, or humans. The administration may include, but is not limited to, oral administration, intravenous injection, intravenous infusion, intraperitoneal injection, or local administration. The tissue or organ may include, but is not limited to, the heart, liver, spleen, lungs, kidneys, brain, or bone marrow.

[0227] The compounds described in this application can exhibit good in vivo safety. This in vivo safety can be defined as the release rate of free toxins in animals after administration of the compounds to animals not exceeding 50%, 40%, 30%, 20%, 10%, 7%, 5%, 4%, 3%, 2%, 1.9%, 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.1%. For example, the in vivo safety can be defined as the absence of toxic effects in animals. The application concentration of the compound described in this application can be 0.5 mg / kg or higher, 1 mg / kg or higher, 2 mg / kg or higher, 3 mg / kg or higher, 4 mg / kg or higher, 5 mg / kg or higher, 10 mg / kg or higher, 20 mg / kg or higher, 30 mg / kg or higher, 50 mg / kg or higher, 70 mg / kg or higher, 100 mg / kg or higher, 200 mg / kg or higher, 500 mg / kg or higher, or 1000 mg / kg or higher. For example, the animals may include, but are not limited to, cats, dogs, horses, pigs, dairy cows, sheep, rabbits, mice, rats, monkeys, or humans. The application may include, but is not limited to, oral administration, intravenous injection, intravenous infusion, intraperitoneal injection, or local administration.

[0228] Reagent test kit

[0229] A seventh aspect of this disclosure relates to a kit containing, for example, a ligand-drug conjugate of formula (I) of this disclosure or a pharmaceutically acceptable salt thereof, or a compound of formula (IIA) or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and / or a pharmaceutical composition of this disclosure.

[0230] Other aspects and advantages of this disclosure will readily become apparent to those skilled in the art from the detailed description below. Only exemplary embodiments of this disclosure are shown and described in the following detailed description. As will be appreciated by those skilled in the art, the content of this disclosure enables them to make modifications to the specific embodiments disclosed without departing from the spirit and scope of the invention to which this disclosure pertains. Accordingly, the descriptions in the accompanying drawings and specification of this disclosure are merely exemplary and not restrictive.

[0231] In addition, this disclosure also provides the following implementation schemes:

[0232] 1. A ligand-drug conjugate or a pharmaceutically acceptable salt thereof, wherein the ligand-drug conjugate has the structure shown in formula (I): mAb—(L—D)z Formula (I);

[0233] Where mAb is a ligand that binds to the target site;

[0234] z is the average conjugation ratio of the drug ligands, and z is selected from an integer or decimal of about 1 to about 16;

[0235] L is a connection unit with the following structure: —L4—L3—L2—L1—; where,

[0236] The L4 is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 1 to 5, 1 bit is connected to the ligand, and 2 bits are connected to L3; R X Selected from C 1-6 Alkyl and C 3-6 cycloalkyl, the C 1-6 Alkyl and C 3-6 The cycloalkyl group is optionally surrounded by one or more radicals selected from halogen, cyano, hydroxyl, C 1-6 Alkyl and C 3-6 Substituents of cycloalkyl groups;

[0237] The L3 is selected from Where s is an integer from 1 to 30, with 1 bit connected to L4 and 2 bits connected to L2;

[0238] The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by 1, 2, or 3 carbon atoms. 1-6 Alkyl groups are substituted;

[0239] The L1 is absent or is a self-destructing unit;

[0240] D is a drug with the structure shown in formula (II):

[0241] The wavy line represents the key connecting L and D;

[0242] R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl groups and C 1-6 Alkoxy;

[0243] W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups.

[0244] 2. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to embodiment 1, wherein, in formula (II), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-33 Halogenated alkyl and C 1-3 Alkoxy;

[0245] Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy;

[0246] More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine.

[0247] 3. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to embodiment 1, wherein, in formula (II), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-3 Halogenated alkyl groups and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen;

[0248] Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 All are hydrogen;

[0249] More preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 All are hydrogen;

[0250] More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen.

[0251] 4. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-3, wherein, in formula (II), R 1 R 2 and R 3 Both are hydrogen.

[0252] 5. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-3, wherein, in formula (II), R 1 It is fluorine, R 2 and R 3 Both are hydrogen.

[0253] 6. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-5, wherein, in formula (II), W is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1- 3-alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0254] Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms;

[0255] More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl;

[0256] More preferably, R 4 and R 5 All are methyl; or,

[0257] More preferably, R 4 and R 5 All are ethyl; or,

[0258] More preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0259] 7. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-5, wherein, in formula (II), W is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3-6 Substituents of cycloalkyl groups;

[0260] Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic groups;

[0261] More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms they are attached to, they form a six-membered heterocyclic group containing 2 to 3 heteroatoms;

[0262] More preferably, R 6 and R 7 All are methyl; or,

[0263] More preferably, R 6 and R 7 All are ethyl; or,

[0264] More preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0265] 8. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-5, wherein, in formula (II), W is... Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0266] Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0267] More preferably, R 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl and methoxy;

[0268] More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups.

[0269] 9. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-8, wherein the L4 is selected from... Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, position 1 is connected to the ligand, and position 2 is connected to L3; R X Selected from C 1-3 Alkyl and C 3-5 cycloalkyl, the C 1-3 Alkyl and C 3-5 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, and C. 1-3 Alkyl groups are substituted.

[0270] 10. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-9, wherein m1 is 1, 2, 3, 4 or 5;

[0271] Preferably, m1 is an integer from 1 to 3;

[0272] More preferably, m1 is 2.

[0273] 11. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-10, wherein m2 is 0, 1, 2, 3, 4 or 5;

[0274] Preferably, m2 is an integer between 0 and 3;

[0275] More preferably, m2 is 0; or

[0276] More preferably, m2 is 2.

[0277] 12. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-11, wherein R X C 1-3 alkyl;

[0278] Preferably, R X It is methyl or ethyl;

[0279] More preferably, R X It is a methyl group.

[0280] 13. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-11, wherein, preferably, R X C 3-5 cycloalkyl;

[0281] Preferably, R XIt is cyclopropyl.

[0282] 14. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-13, wherein L4 is

[0283] 15. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-13, wherein L4 is

[0284] 16. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-13, wherein L4 is

[0285] 17. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-16, wherein the L3 is selected from... Where s is an integer from 1 to 24, with 1 bit connected to L4 and 2 bits connected to L2.

[0286] 18. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-17, wherein s is an integer from 1 to 20;

[0287] Preferably, s is an integer from 2 to 12;

[0288] Preferably, s is an integer from 2 to 8;

[0289] More preferably, s is 2; or

[0290] More preferably, s is 4; or

[0291] More preferably, s is 8.

[0292] 19. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-18, wherein L2 is an amino acid or a peptide consisting of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or stereoisomers thereof; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted;

[0293] Preferably, when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-3 Alkyl groups are substituted;

[0294] More preferably, when the amino acid residue is Lys, the side chain amino group of Lys is replaced by two methyl groups, two ethyl groups, or two n-propyl groups.

[0295] 20. The ligand-drug conjugate according to any one of embodiments 1-19, or a pharmaceutically acceptable salt thereof, wherein the L2 is selected from -Lys-, -Ala-Lys-, -Gly-Lys-, -Lys-Gly-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Lys-Val-, -Ala-Ala-Asn-, -Ala-Ala-Asn-, -Ala-Ala-Asp-, -Ala-Lys-Gly-, -(D-Val)-Le u-Lys-, -Glu-Gly-Lys-, -Gly-Lys-Gly-, -Lys-Ala-Asn-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Val-Ala-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, and -Val-Lys-Gly-Gly-; wherein, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted;

[0296] Preferably, L2 is selected from -Val-Ala-, -Glu-Gly-Lys-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, or -Gly-Gly-Val-Ala-;

[0297] More preferably, L2 is -Gly-Gly-Phe-Gly-; or,

[0298] More preferably, L2 is -Glu-Gly-Lys-, wherein the side chain amino group of Lys is replaced by two methyl groups; or,

[0299] More preferably, L2 is -Glu-Gly-Cit-Gly-.

[0300] 21. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-20, wherein the L1 is absent.

[0301] 22. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-20, wherein the L1 is selected from:

[0302] Of these, bit 1 is connected to L2, and bit 2 is connected to D.

[0303] 23. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-22, wherein L is selected from the structures in Table 1.

[0304] 24. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-23, wherein the mAb may be an antibody or an antigen-binding fragment thereof.

[0305] 25. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-24, wherein the mAb is selected from the group consisting of chimeric antibodies, humanized antibodies and fully human antibodies; preferably, the antigen-binding fragment is selected from the group consisting of Fab′, Fab, F(ab′)2, single-domain antibodies (DABs), Fv, scFv (single-chain Fv).

[0306] 26. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-25, wherein the mAb may be an antibody or an antigen-binding fragment thereof targeting the following targets: 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, O772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CA DM1, CCD79b, CCL5, CCR5, CCR7, CD11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD 40, CD45, CD45(PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.2. c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EG FRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRα, GD2, GEDA, G PC-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra , IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP 14, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC 39A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, short proteoglycans, mesothelin, endothelial peptide receptors, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin α4β7, integrin α5β6, trophoblast cell glycoproteins, and tissue factor.

[0307] 27. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-26, wherein the mAb is an antibody or an antigen-binding fragment thereof targeting the following targets: HER2, HER3, B7H3, TROP2, Claudin 18.2, CD30, CD33, CD70, EGFR and FRα.

[0308] 28. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-Trop-2 antibody or an antigen-binding fragment thereof;

[0309] Preferably, the mAb is datopotamab, sacituzumab, or an antigen-binding fragment thereof.

[0310] 29. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-Her 2 antibody or an antigen-binding fragment thereof;

[0311] Preferably, the mAb is anbenitamab, coprelotamab, disitamab, gancotamab, margetuximab, pertuzumab, timigutuzumab, zanidatamab, trastuzumab, Pertuzumab, or an antigen-binding fragment thereof.

[0312] 30. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-Her3 antibody or an antigen-binding fragment thereof;

[0313] Preferably, the mAb is a barecetamab, duligotuzumab, elgemtumab, istiramumab, lumretuzumab, patritumab, seribantumab, zenocutuzumab, 202-2-1 antibody or its antigen-binding fragment.

[0314] 31. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-EGFR antibody or an antigen-binding fragment thereof; preferably, the mAb is demupitamab, depatuxizumab, futuximab, imgatuzumab, lapatuximab, losatuxizumab, matuzumab, modotuximab, necitumumab, nimotuzumab, panitumumab, pimurutamab, serclutamab, tomouzotuximab, zalutumumab, Cetuximab or an antigen-binding fragment thereof.

[0315] 32. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-B7H3 antibody or an antigen-binding fragment thereof;

[0316] Preferably, the mAb is an antibody of 1D1, 1D1-01, 2E3, 2E3-02, enoblituzumab, mirzotamab, omburtamab, or an antigen-binding fragment thereof.

[0317] 33. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-LIV1 antibody or an antigen-binding fragment thereof;

[0318] Preferably, the mAb is Ladiratuzumab or its antigen-binding fragment.

[0319] 34. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the mAb is an anti-FRα antibody or an antigen-binding fragment thereof;

[0320] Preferably, the mAb is v30384 or its antigen-binding fragment.

[0321] 35. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-27, wherein the average conjugation ratio z of the drug ligand is an integer or decimal from about 1 to about 10;

[0322] Preferably, the average conjugation ratio z of the drug ligand is an integer or fraction from about 3 to about 8; or

[0323] Preferably, the average conjugation ratio z of the drug ligand is an integer or fraction of about 1 to about 2, about 2 to about 3, about 3 to about 4, about 4 to about 5, about 5 to about 6, about 6 to about 7, about 7 to about 8, about 8 to about 9, or about 9 to about 10; or

[0324] Preferably, the average conjugation ratio z of the drug ligand is about 1, about 2, about 3, about 4, about 5, about 6, about 7 or about 8.

[0325] 36. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-35, wherein the ligand-drug conjugate represented by formula (I) is selected from the structures in Table 2.

[0326] 37. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-36, wherein the ligand-drug conjugate represented by formula (I) is selected from the structures in Table 3.

[0327] 38. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-37, wherein the ligand-drug conjugate is substituted with an isotope;

[0328] Preferably, the isotope substitution is deuterium atom substitution.

[0329] 39. A compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound has the structure shown in formula (IA):

[0330] L-D formula (IA);

[0331] Wherein, L is a connecting unit with the following structure: L4'—L3—L2—L1—; where,

[0332] The L4' is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, and 2 bits are connected to L3; R X Selected from C 1-6 Alkyl and C 3-6 cycloalkyl, the C 1-6 Alkyl and C 3-6 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, C 1-6 Alkyl and C 3-6 Substituents of cycloalkyl groups; G1 and G2 are leaving groups;

[0333] The L3 is selected from Where s is an integer from 1 to 30, with 1 bit connected to L4' and 2 bits connected to L2;

[0334] The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by 1, 2, or 3 carbon atoms. 1-6 Alkyl groups are substituted;

[0335] The L1 is absent or is a self-destructing unit;

[0336] D is a drug with the structure shown in formula (II):

[0337] in,

[0338] The wavy line represents the key connecting L and D;

[0339] R 1 R 2 and R 3Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl and C 1-6 Alkoxy;

[0340] W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups.

[0341] 40. The compound according to embodiment 39, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-3 Halogenated alkyl and C 1-3 Alkoxy;

[0342] Preferably, R 1 R 2 and R 3Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy;

[0343] More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine.

[0344] 41. The compound according to embodiment 39, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-3 Halogenated alkyl and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen;

[0345] Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 All are hydrogen;

[0346] More preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 All are hydrogen;

[0347] More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen.

[0348] 42. The compound according to any one of embodiments 39-41, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), R 1 R 2 and R 3 Both are hydrogen.

[0349] 43. A compound according to any one of embodiments 39-41, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), R 1 It is fluorine, R 2 and R 3 Both are hydrogen.

[0350] 44. The compound according to any one of embodiments 39-43, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), W is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0351] Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic groups;

[0352] More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 4 and R 5 Together with the N atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms;

[0353] More preferably, R 4 and R 5All are methyl; or,

[0354] More preferably, R 4 and R 5 All are ethyl; or,

[0355] More preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0356] 45. The compound according to any one of embodiments 39-43, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), W is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1- 3-alkyl and C 3-6 Substituents of cycloalkyl groups;

[0357] Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic groups;

[0358] More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms they are attached to, they form a six-membered heterocyclic group containing 2 to 3 heteroatoms;

[0359] More preferably, R 6 and R 7 All are methyl; or,

[0360] More preferably, R 6 and R 7 All are ethyl; or,

[0361] More preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0362] 46. ​​The compound according to any one of embodiments 39-43, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein in formula (II), W is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0363] Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0364] More preferably, R 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl and methoxy;

[0365] More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups.

[0366] 47. The compound according to any one of embodiments 39-46, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein G1 and G2 are each independently selected from halogen, sulfonyl, sulfonate, nitro, and optionally substituted with one or more of the following groups: alkyl sulfide, aryl sulfide, heteroaryl sulfide, alkyl sulfoxide, aryl sulfoxide, heteroaryl sulfoxide, alkyl sulfonyl, aryl sulfonyl, heteroaryl sulfonyl, wherein each substituent is independently selected from hydrogen, deuterium, halogen, CN, nitro, C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Alkyl carbonyl, halogenated C 1-6 Alkyl carbonyl, 5-10 membered heterocyclic carbonyl, 6-10 membered aryl, 5-16 membered heteroaryl, 6-10 membered aryl carbonyl and 5-16 membered heteroaryl carbonyl;

[0367] Preferably, G1 and G2 are each independently selected from F, Cl, Br, I, OMs (methanesulfonate group), Ots (p-toluenesulfonate group), OTf (trifluoromethanesulfonate group), methanesulfonyl group, ethanesulfonyl group, p-toluenesulfonyl group, naphthalenesulfonyl group, aryl thioether group optionally substituted with one or more substituents, and heteroaryl thioether group optionally substituted with one or more substituents;

[0368] More preferably, G1 and G2 are each independently selected from F, Cl, Br, OMs, OTs, methanesulfonyl, p-toluenesulfonyl and phenyl thioether groups optionally substituted by one or more substituents;

[0369] More preferably, G1 and G2 are each independently selected from Cl, methanesulfonyl, and phenyl thioether group optionally substituted with one or more substituents.

[0370] 48. The compound according to any one of embodiments 39-47, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein G1 is

[0371] 49. The compound according to any one of embodiments 39-48, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein G2 is Cl or methanesulfonyl.

[0372] 50. The compound according to any one of embodiments 39-49, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the L4' is selected from... Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, position 1 is connected to the ligand, and position 2 is connected to L3; R X Selected from C 1-3 Alkyl and C 3-5 cycloalkyl, the C 1-3 Alkyl and C 3-5 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, and C. 1-3 Alkyl groups are substituted.

[0373] 51. The compound according to any one of embodiments 39-50, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein m1 is 1, 2, 3, 4 or 5;

[0374] Preferably, m1 is an integer from 1 to 3;

[0375] More preferably, m1 is 2.

[0376] 52. The compound according to any one of embodiments 39-51, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein m2 is 0, 1, 2, 3, 4 or 5;

[0377] Preferably, m2 is an integer between 0 and 3;

[0378] More preferably, m2 is 0; or

[0379] More preferably, m2 is 2.

[0380] 53. The compound according to any one of embodiments 39-52, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein R X C 1-3 alkyl;

[0381] Preferably, R X It is methyl or ethyl;

[0382] More preferably, R X It is a methyl group.

[0383] 54. The compound or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to any one of embodiments 39-52, wherein R X C 3-5 cycloalkyl;

[0384] Preferably, R X It is cyclopropyl.

[0385] 55. The compound according to any one of embodiments 39-54, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein L4' is

[0386] 56. The compound according to any one of embodiments 39-54, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein L4' is

[0387] 57. The compound according to any one of embodiments 39-54, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein L4' is

[0388] 58. The compound according to any one of embodiments 39-57, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the L3 is selected from... Where s is an integer from 1 to 24, with 1 bit connected to L4' and 2 bits connected to L2.

[0389] 58. The compound or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to any one of embodiments 39-57, wherein s is an integer from 1 to 20;

[0390] Preferably, s is an integer from 2 to 12;

[0391] Preferably, s is an integer from 2 to 8;

[0392] More preferably, s is 2; or

[0393] More preferably, s is 4; or

[0394] More preferably, s is 8.

[0395] 59. The compound according to any one of embodiments 39-58, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein L2 is an amino acid or a peptide consisting of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or stereoisomers thereof; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted;

[0396] Preferably, when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-3 Alkyl groups are substituted;

[0397] More preferably, when the amino acid residue is Lys, the side chain amino group of Lys is replaced by two methyl groups, two ethyl groups, or two n-propyl groups.

[0398] 60. The compound according to any one of embodiments 39-59, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the L2 is selected from -Lys-, -Ala-Lys-, -Gly-Lys-, -Lys-Gly-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Lys-Val-, -Ala-Ala-Asn-, -Ala-Ala-Asn-, -Ala-Ala-Asp-, -Ala-Lys -Gly-, -(D-Val)-Leu-Lys-, -Glu-Gly-Lys-, -Gly-Lys-Gly-, -Lys-Ala-Asn-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Val-Ala-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, and -Val-Lys-Gly-Gly-; wherein, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted;

[0399] Preferably, L2 is selected from -Val-Ala-, -Glu-Gly-Lys-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, or -Gly-Gly-Val-Ala-;

[0400] More preferably, L2 is -Gly-Gly-Phe-Gly-; or,

[0401] More preferably, L2 is -Glu-Gly-Lys-, wherein the side chain amino group of Lys is replaced by two methyl groups; or,

[0402] More preferably, L2 is -Glu-Gly-Cit-Gly-.

[0403] 61. The compound or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to any one of embodiments 39-60, wherein the L1 is absent.

[0404] 62. The compound according to any one of embodiments 39-60, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein L1 is selected from: Of these, bit 1 is connected to L2, and bit 2 is connected to D.

[0405] 63. The compound according to any one of embodiments 39-62, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound of formula (IA) is selected from the structures in Table 4.

[0406] 64. The compound or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to any one of embodiments 39-63, wherein the compound is substituted with an isotope;

[0407] Preferably, the isotope substitution is deuterium atom substitution.

[0408] 65. A compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound has the structure shown in formula (IIA):

[0409] Among them, R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl and C 1-6 Alkoxy;

[0410] W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups.

[0411] 66. The compound according to embodiment 65, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-33 Halogenated alkyl and C 1-3 Alkoxy;

[0412] Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy;

[0413] More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine.

[0414] 67. The compound according to embodiment 65, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-33 Halogenated alkyl and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen;

[0415] Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 All are hydrogen;

[0416] More preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3All are hydrogen;

[0417] More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen.

[0418] 68. The compound according to any one of embodiments 65-67, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein R 1 R 2 and R 3 Both are hydrogen.

[0419] 69. The compound or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to any one of embodiments 65-67, wherein R 1 It is fluorine, R 2 and R 3 Both are hydrogen.

[0420] 70. The compound according to any one of embodiments 65-69, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein W is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0421] Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic groups;

[0422] More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 4 and R 5 Together with the N atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms;

[0423] More preferably, R 4 and R 5 All are methyl; or,

[0424] More preferably, R 4 and R 5 All are ethyl; or,

[0425] More preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0426] 71. The compound according to any one of embodiments 65-69, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein W is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3- Substituents of 6-cycloalkyl groups;

[0427] Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic groups;

[0428] More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms they are attached to, they form a six-membered heterocyclic group containing 2 to 3 heteroatoms;

[0429] More preferably, R 6 and R 7 All are methyl; or,

[0430] More preferably, R 6 and R 7 All are ethyl; or,

[0431] More preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom.

[0432] 72. The compound according to any one of embodiments 65-69, or a tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein W is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0433] Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups;

[0434] More preferably, R 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl and methoxy;

[0435] More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups.

[0436] 73. The compound according to any one of embodiments 65-72, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound is selected from the structures in Table 5A.

[0437] 74. The compound according to any one of embodiments 65-72, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, wherein the compound is substituted with an isotope;

[0438] Preferably, the isotope substitution is deuterium atom substitution.

[0439] 75. A method for preparing a ligand-drug conjugate of formula (I) as described in any one of embodiments 1-38, characterized in that the method comprises contacting a ligand mAb with a structure of formula (IA) as described in any one of embodiments 39-64.

[0440] 76. A pharmaceutical composition, characterized in that the pharmaceutical composition comprises any one of embodiments 1-38, a ligand-drug conjugate or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0441] 77. A pharmaceutical composition, characterized in that the pharmaceutical composition comprises any one of the embodiments 39-64, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0442] 78. A pharmaceutical composition, characterized in that the pharmaceutical composition comprises any one of the following embodiments: 65-74, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0443] 79. Use of a ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-38, or a pharmaceutical composition according to embodiment 76, in the preparation of a medicament for treating and / or preventing tumors.

[0444] 80 Use of a compound according to any one of embodiments 39-64, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, in the preparation of a medicament for treating and / or preventing tumors.

[0445] Preferably, the drug is a ligand-drug conjugate.

[0446] 81. Use of a compound according to embodiments 65-74 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition according to embodiment 78, in the preparation of a medicament for treating and / or preventing tumors.

[0447] 82. A method of treating and / or preventing tumors, comprising administering to a subject in need the ligand-drug conjugate or a pharmaceutically acceptable salt thereof, as described in any one of embodiments 1-38, or the pharmaceutical composition described in embodiment 76.

[0448] 83. A method of treating and / or preventing tumors, comprising administering to a subject in need a compound or tautomer of any one of embodiments 65-74, or a racemic, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition as described in embodiment 78.

[0449] 84. A ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-38, or a pharmaceutical composition according to embodiment 76, for the treatment and / or prevention of tumors.

[0450] 85. A compound according to any one of embodiments 65-74, or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition according to embodiment 78, for the treatment and / or prevention of tumors.

[0451] 86. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is selected from tumors associated with expression of the following group: 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, O772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl , B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79b, CCL5, CCR5, CCR7, CD 11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25 , CD30, CD33, CD37, CD38, CD40, CD45, CD45(PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66 e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.2. c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EG FRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRα, GD2, GEDA, G PC-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra , IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP 14, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC 39A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, short proteoglycans, mesothelin, endothelial peptide receptors, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin α4β7, integrin α5β6, trophoblast cell glycoproteins, and tissue factor.

[0452] 87. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is selected from tumors associated with expression of the following groups: HER2, HER3, B7H3, TROP2, LIV-1, Claudin 18.2, CD30, CD33, CD70, EGFR, and FRα.

[0453] 88. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with HER2 expression.

[0454] 89. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with HER3 expression.

[0455] 90. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with B7H3 expression.

[0456] 91. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with TROP2 expression.

[0457] 92. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with LIV-1 expression.

[0458] 93. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with Claudin 18.2 expression.

[0459] 94. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with CD30 expression.

[0460] 95. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with CD33 expression.

[0461] 96. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with CD70 expression.

[0462] 97. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with EGFR expression.

[0463] 98. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is a tumor associated with FRα expression.

[0464] 99. The use according to any one of embodiments 79-81, the method of embodiment 82 or 83, the ligand-drug conjugate of embodiment 84 or a pharmaceutically acceptable salt or pharmaceutical composition thereof, the compound of embodiment 85 or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt or pharmaceutical composition thereof, characterized in that the tumor is selected from the group consisting of: lung cancer, breast cancer, rectal cancer, colon cancer, esophageal cancer, gastric cancer, liver cancer, gallbladder cancer, bile duct cancer, kidney cancer, bladder cancer, urothelial carcinoma, head and neck cancer, etc. Cancer, nasopharyngeal carcinoma, prostate cancer, cervical cancer, endometrial cancer, ovarian cancer, pancreatic cancer, melanoma, bone cancer, mesothelioma, gastrointestinal stromal tumor, sarcoma, glioma, thyroid cancer, salivary gland tumor, glioblastoma, neuroblastoma, gastric mucinous tumor, lymphoma, leukemia, plasmacytoma, sinoatrial node cell tumor, tenosynovial giant cell tumor, brain cancer, squamous cell carcinoma, epidermal cancer, non-Hodgkin's lymphoma; preferably, wherein the cancer is selected from breast cancer, prostate cancer, lung cancer, pancreatic cancer, ovarian cancer, cervical cancer, endometrial cancer, bladder cancer, glioma, malignant lymphoma, liver cancer, and leukemia;

[0465] Preferably, the cancer is pancreatic cancer, colorectal cancer, lung cancer, stomach cancer, or breast cancer.

[0466] 100. A kit comprising a ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of embodiments 1-38, a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and / or a pharmaceutical composition according to embodiments 93 or 95.

[0467] Example

[0468] The following embodiments are used to further describe this disclosure, but these embodiments are not intended to limit the scope of this disclosure.

[0469] The structure of the compound was determined by nuclear magnetic resonance (NMR) and / or mass spectrometry (MS). NMR shifts (δ) were measured in 10⁻¹⁰ increments. - 6 The unit (ppm) is given. NMR measurements were performed using a Bruker AVANCENEO 500M NMR spectrometer. The solvents used were deuterated dimethyl sulfoxide (DMSO-d6), deuterated chloroform (CDCl3), and deuterated methanol (CD3OD), with tetramethylsilane (TMS) as the internal standard.

[0470] MS measurements were performed using an Agilent 1200 / 1290DAD-6110 / 6120 Quadrupole MS LC-MS system (manufacturer: Agilent, MS model: 6110 / 6120 Quadrupole MS), a Waters ACQuity UPLC-QD / SQD system (manufacturer: Waters, MS model: Waters ACQuity Qda Detector / Waters SQ Detector), or a THERMO Ultimate 3000-Q Exactive system (manufacturer: THERMO, MS model: THERMO Q Exactive).

[0471] High-performance liquid chromatography (HPLC) analysis was performed using an Agilent HPLC 1200DAD, an Agilent HPLC 1200VWD, and a Waters HPLC e2695-2489 HPLC system.

[0472] Chiral HPLC analysis was performed using an Agilent 1260DAD high-performance liquid chromatograph.

[0473] High-performance liquid chromatography (HPLC) preparative chromatography was performed using Waters 2767, Waters 2767-SQ Detecor2, Shimadzu LC-20AP, and Gilson-281 preparative chromatographs.

[0474] Chiral preparative chromatography was performed using a Shimadzu LC-20AP preparative chromatograph.

[0475] The CombiFlash rapid preparation system uses a CombiFlash Rf200 (TELEDYNE ISCO).

[0476] The silica gel plates used for thin-layer chromatography are Yantai Huanghai HSGF254 silica gel plates. The silica gel plates used in thin-layer chromatography (TLC) have a diameter of 0.15 mm to 0.2 mm, and the diameter of the silica gel plates used for thin-layer chromatography separation and purification products is 0.4 mm to 0.5 mm.

[0477] Silica gel column chromatography typically uses 200–300 mesh or 300–400 mesh silica gel as the carrier.

[0478] The known starting materials disclosed herein can be synthesized using methods known in the art, or can be purchased from companies such as Shanghai Titan Technology, ABCR GmbH & Co. KG, Acros Organics, Aldrich Chemical Company, Accela ChemBio Inc, and Bid Pharmaceuticals.

[0479] Unless otherwise specified in the examples, all reactions can be carried out under an argon or nitrogen atmosphere.

[0480] Argon or nitrogen atmosphere refers to a reaction flask connected to an argon or nitrogen gas balloon with a volume of approximately 1L.

[0481] A hydrogen atmosphere refers to a reaction flask connected to a hydrogen balloon with a volume of approximately 1L.

[0482] The pressurized hydrogenation reaction was performed using a Parr 3916EKX hydrogenator and a Qinglan QL-500 hydrogen generator or an HC2-SS hydrogenator.

[0483] The hydrogenation reaction is usually carried out under vacuum, filled with hydrogen gas, and repeated 3 times.

[0484] The microwave reaction was performed using a CEM Discover-S 908860 microwave reactor.

[0485] Unless otherwise specified in the examples, "solution" refers to an aqueous solution.

[0486] Unless otherwise specified in the examples, the reaction temperature is room temperature, which is 20℃~30℃.

[0487] The reaction process in the examples was monitored using thin-layer chromatography (TLC). The developing solvent used in the reaction, the eluent system used for column chromatography to purify the compounds, and the developing solvent system for TLC included, but were not limited to: A: n-hexane / ethyl acetate system, B: dichloromethane / methanol system. The volume ratio of the solvent was adjusted according to the polarity of the compounds. Small amounts of basic or acidic reagents such as triethylamine and acetic acid could also be added for adjustment.

[0488] The specific enantiomers in the examples can be obtained by separation using chiral HPLC. When a specific geometrical isomer is desired, chromatography, recrystallization, and other conventional separation operations can also be used. Alternatively, undesirable enantiomers can be racemiced to desired enantiomers in the presence of an acid or base, according to methods known to those skilled in the art or as described in the accompanying examples.

[0489] Example 1: Preparation of drug D

[0490] Example 1-1: Synthesis of toxin T1a (Zymeworks Inc., FD5, DOI: 10.1158 / 1535-7163.MCT-23-0822)

[0491] Step 1: Synthesize compound T1a-b: tert-butyl (2-fluoro-5-formyl-4-nitrophenyl)carbamate, 2-methylpropan-2-yl[(2-fluoro-4-formyl-5-nitrophenyl)amino]methanoate

[0492] Compound T1a-a (5-bromo-4-fluoro-2-nitrobenzaldehyde, CAS RN: 213382-45-7, 5 g, 20.16 mmol) was dissolved in anhydrous toluene (55 mL) at room temperature. Tert-butyl carbamate (2.83 g, 24.19 mmol), tris(dibenzylacetone)palladium (CAS RN: 51364-51-3, 0.92 g, 1.01 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (CAS RN: 564483-18-7, 1.92 g, 4.03 mmol), and cesium carbonate (13.14 g, 40.32 mmol) were added sequentially. The reaction mixture was protected with nitrogen and stirred overnight at 90°C. After the reaction was complete, the mixture was cooled to room temperature and then quenched with water (200 mL). After separating the organic and aqueous phases in the reaction solution, the aqueous phase was extracted three times with ethyl acetate (200 mL × 3). All organic phases were combined and washed three times with saturated brine (300 mL × 2). After drying with anhydrous sodium sulfate, the organic solvent in the organic phase was evaporated under reduced pressure. The obtained residue was purified by preparative normal-phase column chromatography (PE / EA) to obtain a brown solid, which was compound T1a-b (5 g, 17.8 mmol, yield 88%).

[0493] LC-MS(m / z,C12H13FN2O5)=285.0[(M+H)] + .

[0494] 1H-NMR (400MHz, CDCl3-d) δ10.44(s,1H),8.76(d,J=7.6Hz,1H),7.92(d,J=10.4Hz,1H),7.03(s,1H),1.55(s,9H).

[0495] Step 2: Synthesize compound T1a-c:(4-amino-2-fluoro-5-formylphenyl)carbamate, tert-butyl(4-amino-2-fluoro-5-formylphenyl)carbamate

[0496] Compound T1a-b (3 g, 10.55 mmol) was dissolved in ethanol (36 mL) at room temperature, followed by the sequential addition of water (9 mL), ammonium chloride (0.91 g, 17.10 mmol), and iron powder (2.36 g, 42.22 mmol). After the addition was complete, the reaction mixture was heated to 80°C and stirred for 1 hour. The reaction solution was cooled to room temperature and filtered to remove excess iron powder. The resulting filtrate was extracted three times with ethyl acetate (50 mL × 3). The resulting organic phase was washed twice with saturated brine (30 mL × 2), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by preparative normal-phase column chromatography (PE / EA) to obtain a brown solid, which was compound T1a-c (1.6 g, 5.38 mmol, yield 51%).

[0497] LC-MS(m / z,C12H15FN2O3)=255.0[(M+H)] + .

[0498] 1 H-NMR (400MHz, CDCl3-d) δ9.80 (s, 1H), 8.13 (s, 1H), 7.26 (s, 1H), 6.37 (d, J = 12.8Hz, 1H), 6.12 (s, 2H), 1.52 (s, 9H).

[0499] Step 3: Synthesize compound T1a-d:(S)-(4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0500] (S)-4-ethyl-4-hydroxy-7,8-dihydro-1H-pyrano[3,4-f]indolizine-3,6,10(4H)-trione (CAS RN: 110351-94-5; 1.38 g, 5.24 mmol) was dissolved in anhydrous toluene (160 mL) at room temperature. Compound T1a-c (1.6 g, 6.29 mmol) and p-toluenesulfonic acid hydrate (0.1 g, 0.52 mmol) were added. After the addition was complete, the reaction mixture was heated to 110 °C and stirred for 2 hours. After the reaction mixture was cooled to room temperature, the organic solvent was evaporated under reduced pressure to obtain the reaction residue. The crude product, a brown solid, obtained by washing the reaction residue with methyl tert-butyl ether was compound T1a-d (1.1 g, 2.28 mmol, yield 43.5%).

[0501] LC-MS(m / z,C25H24FN3O6): 482.0[(M+H)] + .

[0502] 1 HNMR(400MHz,DMSO-d6)δ9.49(s,1H),8.66(s,1H),8.44(d,J=8.4Hz,1H),7.96(d,J=12Hz,1H),7.3 0(s,1H),6.50(s,1H),5.42(s,2H),5.26(s,2H),1.90-1.82(m,2H),1.52(s,9H),0.89-0.85(m,3H).

[0503] Step 4: Synthesize compound T1a-e:(S)-(4-ethyl-8-fluoro-4-hydroxy-11-hydroxymethyl-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0504] Compound T1a-d (600 mg, 1.25 mmol) was dissolved in anhydrous methanol (54 mL) at room temperature, followed by the addition of ferrous sulfate heptahydrate (180 mg) and 7% dilute sulfuric acid (0.6 mL). The reaction mixture was heated to 65°C and stirred for 30 minutes. Then, 30% hydrogen peroxide aqueous solution (3.6 mL) was added, and stirring continued at 65°C for another 30 minutes. After cooling the reaction mixture to room temperature, it was poured directly into ice water (150 mL). After standing for 1 hour, the brown solid obtained by filtering the ice water mixture was the crude product of compound T1a-e (130 mg, 0.25 mmol, yield 20%).

[0505] LC-MS(m / z,C26H26FN3O7)=512.0[(M+H)] + .

[0506] 1 H NMR (400MHz, DMSO-d6) δ9.48(s,1H),8.48(d,J=8.4Hz,1H),7.95(d,J=12Hz,1H),7.29(s,1H),6.49(s,1H),5.83- 5.81(m,1H),5.43(s,2H),5.39(s,2H),5.17(d,J=4.4Hz,2H),1.91-1.81(m,2H),1.52(s,9H),0.89-0.86(m,3H).

[0507] Step 5: Synthesize compound T1a:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione.

[0508] Compound T1a-e (70 mg, 0.14 mmol) was dissolved in anhydrous dichloromethane (1.5 mL) at room temperature, followed by the dropwise addition of trifluoroacetic acid (0.5 mL). After the addition was complete, the reaction mixture was stirred at room temperature for 2 hours. The organic solvent in the reaction mixture was evaporated under reduced pressure to obtain the crude product. The crude product was further purified by preparative reversed-phase chromatography (ACN / H2O, 0.1% FA) to obtain a yellow solid, which was compound T1a (4 mg, 0.01 mmol, purified yield 7.1%).

[0509] LC-MS(m / z,C21H18FN3O5)=412.0[(M+H)] + .

[0510] 1 H NMR(400MHz,DMSO-d6)δ7.75(d,J=12.4Hz,1H),7.21-7.19(m,2H),6.45(s,1H),6.10(s,2H),5.71- 5.68(m,1H),5.40(s,2H),5.33(s,2H),5.06(d,J=5.2Hz,2H),1.88-1.81(m,2H),0.89-0.85(m,3H).

[0511] Examples 1-2: Synthesis of compound T1b (Zymeworks Inc., FD4, DOI: 10.1158 / 1535-7163.MCT-23-0822)

[0512] Step 1: Synthesize compound T1b:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0513] Compound T1a-d (100 mg, 0.21 mmol) was dissolved in dichloromethane (2 mL) at room temperature. Trifluoroacetic acid (1 mL) was then added to the reaction mixture, and the mixture was stirred for 2 hours at room temperature. The crude trifluoroacetate was obtained by evaporation of the solvent under reduced pressure and then purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T1b (10.0 mg, yield of 12.63% after purification).

[0514] LC-MS(m / z,C20H16FN3O4)=382.0[(M+H)] + .

[0515] 1HNMR(400MHz,DMSO-d6)δ8.33(s,1H),7.76(d,J=12.5Hz,1H),7.21(s,1H),7.14(d,J=9.7Hz,1H), 6.47(s,1H),6.09(s,2H),5.40(s,2H),5.19(s,2H),1.85(p,J=6.9Hz,2H),0.87(t,J=7.3Hz,3H).

[0516] Examples 1-3: Synthesis of compound T2a

[0517] Step 1: Synthesize compound T2a-a:(S)-(4-ethyl-8-fluoro-11-formyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0518] Compound T1a-e (500 mg, 0.98 mmol) was dissolved in anhydrous dimethyl sulfoxide (7 mL) at room temperature. Then, Desmond-Martin oxidant (829.2 mg, 1.95 mmol) was added, and the mixture was stirred at room temperature for 1 hour. The reaction solution was used directly for the next reaction after filtering out the solid insoluble matter.

[0519] LC-MS(m / z,C26H24FN3O7)=510.0[(M+H)] + .

[0520] Step 2: Synthesize compound T2a-b:(S)-(4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0521] N,O-dimethylhydroxylamine hydrochloride (CAS RN: 6638-79-5; 200 mg, 2.05 mmol) was added to the filtered reaction solution from the previous step at room temperature. After stirring the reaction solution at room temperature for 2 hours, the brown solid obtained by preparative reversed-phase column chromatography (ACN / H2O, 0.1% FA) was compound T2a-b (120 mg, 0.22 mmol, two-step yield 56%).

[0522] LC-MS(m / z,C27H27FN4O7)=539.2[(M+H)] + .

[0523] 1 HNMR (400MHz, DMSO-d6) δ9.55(s,1H),9.01(s,1H),8.88(d,J=8.8Hz,1H),7.99(d,J=11.6Hz,1H),7.30(s,1 H),6.51(s,1H),5.42(s,2H),5.29(s,2H),4.14(s,3H),1.90-1.83(m,2H),1.53(s,9H),0.90-0.86(m,3H).

[0524] Step 3: Synthesize compound T2a: (S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-methyl oxime, (S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-methyl oxime

[0525] Compound T2a-b (50 mg, 0.09 mmol) was dissolved in 1.5 mL of dichloromethane at room temperature. 0.5 mL of trifluoroacetic acid was added dropwise to the reaction mixture, and the reaction was continued with stirring at room temperature for 2 hours. The trifluoroacetate obtained after evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2a (10 mg, 0.02 mmol, yield 23.3% after preparative purification).

[0526] LC-MS(m / z,C22H19FN4O5)=439.0[(M+H)] + .

[0527] 1 H NMR (400MHz, DMSO-d6) δ8.90(s,1H),7.81(d,J=12Hz,1H),7.62(d,J=9.6Hz,1H),7.21(s,1H),6.47 (s,1H),6.24(s,2H),5.40(s,2H),5.26(s,2H),4.12(s,3H),1.89-1.82(m,2H),0.89-0.85(m,3H).

[0528] Examples 1-4: Synthesis of compound toxin T2b

[0529] Step 1: Synthesize compound T2b-a: 2-(neopentyloxy)isoindoline-1,3-dione.

[0530] Triphenylphosphine (4.46 g, 17.02 mmol) was dissolved in 20 mL of tetrahydrofuran solvent at room temperature. After cooling the reaction solution to 0°C, the air in the reaction apparatus was replaced with nitrogen. Under nitrogen protection, neopentyl alcohol (1 g, 11.34 mmol) and N-hydroxyphthalimide (CAS RN: 524-38-9; 1.85 g, 11.34 mmol) were dissolved in an additional 5 mL of tetrahydrofuran solvent and added dropwise to the reaction solution. After the addition was complete, the reaction solution was stirred at 0°C for 3 minutes. Finally, diisopropyl azodicarbonate (CAS RN: 2446-83-5; 3.44 g, 17.0 mmol) was slowly added dropwise to the reaction solution at 0°C. After the reaction solution was warmed to room temperature and stirred for 2 hours, the initial reactants were detected by liquid chromatography-mass spectrometry (LC-MS / MS) to confirm complete consumption. The colorless oil obtained by evaporating the solvent under reduced pressure in the reaction solution is compound T2b-a (500 mg, yield 18.89%).

[0531] LC-MS(m / z,C13H15NO3)=234.2[(M+H)] + .

[0532] 1 H NMR (400MHz, CDCl3) δ7.83 (dd, J = 5.5, 3.1 Hz, 2H), 7.74 (dd, J = 5.5, 3.1 Hz, 2H), 3.89 (s, 2H), 1.10 (s, 9H).

[0533] Step 2: Synthesize compound T2b-b: O-Neopentylhydroxylamine

[0534] Compound T2b-a (100 mg, 0.43 mmol) was dissolved in dichloromethane (5 mL) at room temperature. Hydrazine hydrate (CAS RN: 10217-52-4; 0.1 mL) was added to the reaction solution, and the reaction mixture was stirred at room temperature for 2 hours. Liquid chromatography-mass spectrometry (LC-MS) was used to confirm the complete consumption of the starting materials. The solvent was evaporated under reduced pressure to obtain the crude product, which was then purified using preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O B: ACN) to obtain a colorless oily substance, which was compound T2b-b (40 mg, yield 90.44%).

[0535] LC-MS(m / z,C5H13NO)=104.2[(M+H)] + .

[0536] 1HNMR (400MHz, CDCl3) δ3.62 (s, 2H), 1.08 (s, 9H).

[0537] Steps 3-4: Synthesize compound T2b:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-neopentyl oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-neopentyl oxime

[0538] Compounds T2b-b (20 mg, 0.19 mmol) and T2a-a (98.77 mg, 0.19 mmol) were dissolved in dimethyl sulfoxide (DMSO, 5 mL) at room temperature. The reaction mixture was stirred at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS) was used to detect the complete consumption of the starting materials, yielding a reaction solution containing compound T2b-c.

[0539] Trifluoroacetic acid (1 ml) was added dropwise to the reaction solution with stirring. After the addition was complete, stirring was continued at room temperature for 1 hour. The solvent of the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2b (5 mg, 0.01 mmol, yield of 3% after preparative purification).

[0540] LC-MS(m / z,C26H27FN4O5)=495.4[(M+H)] + .

[0541] 1 H NMR(400MHz, DMSO-d6)δ8.95(s,1H),7.82(d,J=12.2Hz,1H),7.67(d,J=9.5Hz,1H),7.21(s,1H),6.47(s,1H), 6.22(s,2H),5.40(s,2H),5.26(s,2H),4.10(s,2H),1.86(p,J=6.9Hz,2H),1.04(s,9H),0.88(t,J=7.3Hz,3H).

[0542] Examples 1-5: Synthesis of compound T2c

[0543] Steps 1-2: Synthesize compound T2c:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-hydroxyethyl)oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-hydroxyethyl)oxime

[0544] Compound T2a-a (200 mg, 0.39 mmol) and 2-aminooxyethanol (CAS No. 3279-95-6, 30.26 mg, 0.39 mmol) were dissolved in dimethyl sulfoxide (DMSO, 4 mL) at room temperature. After stirring the reaction solution at room temperature for 16 hours, liquid chromatography-mass spectrometry (LC-MS) was used to monitor the complete consumption of the starting materials, yielding a reaction solution containing compound T2c-a.

[0545] Then, trifluoroacetic acid (TFA, 1 mL) was added to the reaction solution, and the mixture was reacted at room temperature for 1 hour. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2c (4.41 mg, 0.0094 mmol, yield of 3.15% after preparative purification).

[0546] LC-MS(m / z,C23H21FN4O6)=469.2[(M+H)] + .

[0547] 1H NMR (400MHz, DMSO-d6) δ8.91(s,1H),7.80(d,J=12.2Hz,1H),7.61(d,J=9.5Hz,1H),7.21(s,1H),6.47(s,1H),6.23(s,2H),5 .40(s,2H),5.24(s,2H),4.87(s,1H),4.35(t,J=5.1Hz,2H),3.78(t,J=5.2Hz,2H),1.93–1.78(m,2H),0.88(t,J=7.3Hz,3H).

[0548] Examples 1-6: Synthesis of compound T2d

[0549] Step 1: Synthesize compound T2d-a: 2-(2-morpholinoethoxy)isoindoline-1,3-dione, 2-(2-morpholinoethoxy)isoindoline-1,3-dione

[0550] Triphenylphosphine (6 g, 22.87 mmol) was dissolved in tetrahydrofuran (20 mL) at room temperature. After cooling the reaction solution to 0°C, the air in the reaction apparatus was replaced with nitrogen. Under nitrogen protection, 2-morpholinoethanol (CAS.RN: 622-40-2, 2 g, 15.25 mmol) and N-hydroxyphthalimide (CAS RN: 524-38-9; 2.49 g, 15.25 mmol) were dissolved in an additional tetrahydrofuran (5 mL) and added dropwise to the reaction solution. After the addition was complete, the reaction solution was stirred at 0°C for 30 minutes. Finally, diisopropyl azodicarbonate (4.6 mL, 22.9 mmol) was slowly added dropwise to the reaction solution at 0°C. After the reaction solution was warmed to room temperature and stirred for another 2 hours, the initial reactants were detected by liquid chromatography-mass spectrometry (LC-MS / MS) to confirm complete consumption. The colorless oily substance obtained by evaporating the solvent under reduced pressure from the reaction solution is compound T2b-a (2g, yield 47.48%). The crude product is used directly in the next step.

[0551] LC-MS(m / z,C14H16N2O4)=277.2[(M+H)] + .

[0552] 1 H NMR(400MHz, CDCl3) δ7.84(dd,J=3.1,5.5,2H),7.76(dd,J=3.1,5.5,2H),4.3 6(t,J=5.1,2H), 3.60(t,J=4.5,4H), 2.80(t,J=5.1,2H), 2.50(t,J=4.5,4H).

[0553] Step 2: Synthesize compound T2d-b: O-(2-morpholinoethyl)hydroxylamine

[0554] Compound T2d-a (500 mg, 5.81 mmol) was dissolved in dichloromethane (5 mL) at room temperature. Hydrazine hydrate (58.01 mg, 5.81 mmol) was added to the reaction solution, and the reaction mixture was stirred at room temperature for 2 hours. Liquid chromatography-mass spectrometry (LC-MS) was used to monitor the depletion of the starting material. Further purification using preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm; mobile phase: A: 0.1% FA / H2O; B: ACN) yielded a colorless oily substance, which was compound T2d-b (200 mg, yield 75.6%).

[0555] LC-MS(m / z,C6H14N2O2)=147.2[(M+H)] + .

[0556] 1 H NMR (400MHz, CD3OD) δ4.56 (t, J = 3.7, 2H), 4.01 (br s, 4H), 3.59 (t, J = 3.9, 2H), 3.40 (br s, 4H).

[0557] Steps 3-4: Synthesize compound T2d:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-morpholinoethyl)oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-morpholinoethyl)oxime

[0558] At room temperature, compounds T2d-b (200 mg, 1.37 mmol) and T2a-a (697 mg, 1.37 mmol) were dissolved in dimethyl sulfoxide (DMSO, 5 mL). After stirring the reaction solution at room temperature for 1 hour, liquid chromatography-mass spectrometry (LC-MS) was used to monitor the complete consumption of the starting materials, resulting in a reaction solution containing compound T2d-c.

[0559] Then, trifluoroacetic acid (TFA, 2 mL) was added to the reaction solution, and the mixture was reacted at room temperature for 1 hour. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2d (3.81 mg, 0.007 mmol, yield of 8.8% after preparative purification).

[0560] LC-MS(m / z,C27H28FN5O6)=538.4[(M+H)] + .

[0561] 1 H NMR (400MHz, DMSO-d6) δ8.91(s,1H),7.81(d,J=12.2Hz,1H),7.61(d,J=9.5Hz,1H),7.21(s,1H),6.47(s,1H),6.22(s,2H),5.40 (s,2H),5.25(s,2H),4.46-4.43(m,2H),3.61–3.59(m,4H),2.77-2.74m,2H),2.51(s,4H),1.87-1.83(m,2H),0.89-0.85(m,3H).

[0562] Examples 1-6: Synthesis of compound T2e

[0563] Steps 1-2: Synthesize compound T2e:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-methoxyethyl)oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-methoxyethyl)oxime

[0564] Compound T2a-a (200 mg, 0.39 mmol) and O-(2-methoxyethyl)-hydroxylamine (CAS RN: 54149-39-2; 35.77 mg, 0.39 mmol) were dissolved in dimethyl sulfoxide (DMSO, 5 mL) at room temperature. After stirring at room temperature for 16 hours, liquid chromatography-mass spectrometry (LC-MS) confirmed the complete consumption of the starting materials, yielding a reaction solution containing compound T2e-a.

[0565] Then, trifluoroacetic acid (TFA, 1 mL) was added to the reaction solution, and the mixture was reacted at room temperature for 1 hour. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2e (5.0 mg, yield of 12.08% after preparative purification).

[0566] LC-MS(m / z,C24H23FN4O6)=483.0[(M+H)] + .

[0567] 1 H NMR (400MHz, DMSO-d6) δ8.94(s,1H),7.82(d,J=12.2Hz,1H),7.63(d,J=9.5Hz,1H),7.21(s,1H),6.47(s,1H),6.23(s,2H), 5.40(s,2H),5.27(s,2H),4.50–4.41(m,2H),3.77–3.70(m,2H),3.34(s,3H),1.85(q,J=7.1Hz,2H),0.88(t,J=7.3Hz,3H).

[0568] Examples 1-7: Synthesis of compound T2f

[0569] Steps 1-2: Synthesize compound T2f:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-benzyl oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-benzyl oxime

[0570] Compound T2a-a (200 mg, 0.39 mmol) and O-benzyl hydroxylamine (CAS RN: 622-33-3, 35 mg, 0.39 mmol) were dissolved in dimethyl sulfoxide (4 mL) at room temperature. The reaction mixture was stirred at room temperature for 16 hours, and the initial reactants were consumed as monitored by liquid chromatography-mass spectrometry (LC-MS). Trifluoroacetic acid (TFA, 1 mL) was then added to the reaction mixture, and the reaction was carried out at room temperature for 1 hour. The initial reactants were consumed as monitored by LC-MS. The organic solvent in the reaction mixture was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2f (5.0 mg, 11.95% yield after preparative purification).

[0571] LC-MS(m / z,C28H23FN4O5)=515.3[(M+H)] + .

[0572] 1 H NMR (400MHz, DMSO-d6) δ8.97(s,1H),7.81(d,J=12.2Hz,1H),7.62(d,J=9.5Hz,1H),7.56–7.53(m,2H),7.43(dd,J=8.2,6.5Hz,2H),7.37(d,J=7 .3Hz,1H),7.20(s,1H),6.47(s,1H),6.22(s,2H),5.42(s,2H),5.38(s, 2H) 5.22 (d, J = 2.5Hz, 2H), 1.86 (p, J = 6.9Hz, 2H), 0.87 (t, J = 7.3Hz, 3H).

[0573] Examples 1-8: Synthesis of compound T2g

[0574] Step 1: Synthesize compound T2g-a: 3-(bromomethyl)phenoxy)(tert-butyl)dimethylsilane

[0575] At room temperature, tert-butyldimethylchlorosilane (0.97 g, 6.42 mmol) was added to a solvent of m-hydroxybenzyl bromide (1.0 g, 5.35 mmol) and imidazole (0.55 g, 8.02 mmol) in N,N-dimethylformamide (CAS RN: 68-12-2; 10.0 mL). After the addition was complete, the reaction mixture was stirred at room temperature for 4 hours. The reaction mixture was quenched with 100 mL of ice water. The reaction mixture was extracted with dichloromethane (50 mL × 2). After separation of the organic phase, the organic solvent in the organic phase was evaporated under reduced pressure to obtain the reaction residue. The residue was directly purified by preparative normal-phase column chromatography (PE / EA = 20:1 to 10:1) to obtain a colorless liquid, which was compound T2g-a (0.76 g, 2.52 mmol, reaction yield 47.18%).

[0576] 1 H NMR (400MHz, DMSO-d6) δ7.25(m,1H),7.02(m,1H),6.92(m,1H),6.81(m,1H),4.71(s,2H),0.95(s,9H),0.19(s,6H).

[0577] Step 2: Synthesize compound T2g-b: 2-((3-((tert-butyldimethylsilyl)oxy)benzyl)oxy)isoindoline-1,3-dione, 2-((3-((tert-butyldimethylsilyl)oxy)benzyl)oxy)isoindoline-1,3-dione

[0578] Compound T2g-a (700 mg, 2.32 mmol) was dissolved in N,N-dimethylformamide (10.0 mL) at room temperature. N-hydroxyphthalimide (CAS No. 524-38-9, 379 mg, 2.32 mmol) and N,N-diisopropylethylamine (601 mg, 4.65 mmol) were added sequentially to the reaction solution. After the additions were complete, the mixture was stirred at room temperature for 2 hours, and the reaction was quenched with 50 mL of water. The reaction solution was extracted twice with dichloromethane (30 mL × 2). After separating the organic phase, the solvent in the organic phase was evaporated under reduced pressure to obtain the reaction residue. This residue was directly purified by preparative normal-phase column chromatography (PE / EA) to obtain a colorless liquid, which was compound T2g-b (175 mg, 0.46 mmol, yield 19.64%).

[0579] LC-MS(m / z,C21H25NO4Si)=406.2[(M+23)] + .

[0580] 1 H NMR(400MHz,CHCl3-d)δ7.80(m,2H),7.73(m,2H),7.23(m,1H),7.15–7.10(m ,1H),6.99(m,1H),6.86–6.81(m,1H),5.16(s,2H),0.96(s,9H),0.16(s,6H).

[0581] Step 3: Synthesize compound T2g-c:O-(3-((tert-butyldimethylsilyl)oxy)benzyl)hydroxylamine,O-(3-((tert-butyldimethylsilyl)oxy)benzyl)hydroxylamine

[0582] Compound T2g-b (150 mg, 0.39 mmol) was dissolved in ethanol (2 mL) at room temperature, and hydrazine hydrate (46 mg, 0.78 mmol) was added. The reaction mixture was stirred at room temperature for 2 hours, and then the organic solvent in the reaction mixture was evaporated under reduced pressure to obtain the crude product. The crude product was purified by preparative normal-phase column chromatography, and the resulting oil was the target compound T2g-c (80 mg, 0.32 mmol, yield 80.71%).

[0583] LC-MS(m / z,C13H23NO2Si)=254.2[(M+H)] + .

[0584] 1HNMR(400MHz,DMSO-d6)δ7.21(m,1H),6.92–6.88(m,1H),6.80–6.73(m,2H),6.04(s,2H),4.51(s,2H),0.95(s,9H),0.18(s,6H).

[0585] Steps 4-5: Synthesize compound T2g:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(3-hydroxybenzyl)oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(3-hydroxybenzyl)oxime

[0586] Compound T2a-a (80 mg, 0.16 mmol) and compound T2g-c (40 mg, 0.16 mmol) were dissolved in dimethyl sulfoxide (4 mL) at room temperature. The reaction mixture was stirred at room temperature for 1 hour, and liquid chromatography-mass spectrometry was used to monitor the complete consumption of the starting materials, yielding a reaction solution containing compound T2g-d.

[0587] Trifluoroacetic acid (TFA, 306 mg, 2.68 mmol) was then added to the reaction solution, and the reaction was carried out at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS / MS) was used to monitor the complete consumption of the starting materials. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. This crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain the solid compound T2g (16 mg, 0.03 mmol, reaction yield 15%).

[0588] LC-MS(m / z,C28H23FN4O6)=531.2[(M+H)] + .

[0589] 1HNMR(400MHz, DMSO-d6)δ9.44(s,1H),8.97(s,1H),7.82(d,J=12.3Hz,1H),7.65(d,J=9.6Hz,1H),7.25–7.18(m,2H),6.94-6.80 (m,2H),6.74(m,1H),6.48(s,1H),6.22(s,2H),5.41(s,2H),5.30(s,2H),5.25(s,2H),1.90–1.81(m,2H),0.87(t,J=7.4Hz,3H).

[0590] Examples 1-9: Synthesis of compound T2h

[0591] Step 1: Synthesize compound T2h-a:2-((2-hydroxybenzyl)oxy)isoindoline-1,3-dione, 2-((2-hydroxybenzyl)oxy)isoindoline-1,3-dione

[0592] Triphenylphosphine (6 g, 22.87 mmol) was dissolved in tetrahydrofuran solvent (20 mL) at room temperature. After cooling the reaction solution to 0°C, the air in the reaction apparatus was replaced with nitrogen. Under nitrogen protection, salicylol (CAS RN: 90-01-7, 1 g, 8.06 mmol) and N-hydroxyphthalimide (CAS RN: 524-38-9; 1.45 g, 8.86 mmol) were dissolved in additional tetrahydrofuran solvent (5 mL) and added dropwise to the reaction solution. After the addition was complete, the reaction solution was stirred at 0°C for 30 minutes. Finally, diisopropyl azodicarbonate (4.6 mL, 8.66 mmol) was slowly added dropwise to the reaction solution at 0°C. After stirring the reaction solution at 50°C for 16 hours, the consumption of the starting materials was detected by liquid chromatography-mass spectrometry. The colorless oily substance obtained by evaporating the solvent under reduced pressure in the reaction solution is compound T2h-a (2g, yield 82.99%).

[0593] LC-MS(m / z,C15H11NO4)=270.2[(M+H)] + .

[0594] 1 H NMR(400MHz, CDCl3)δ7.90-7.86(m,2H),7.81–7.76(m,2H),7.63(bs,1H),7.35-7 .31(m,1H),7.25-7.23(m,1H),7.05-7.03(m,1H),6.93-6.88(m,1H),5.25(s,2H).

[0595] Step 2: Synthesize compound T2h-b: 2-((aminooxy)methyl)phenol

[0596] Compound T2h-a: (2-((2-hydroxybenzyl)oxy)isoindoline-1,3-dione; 1.6 g, 5.94 mmol) was dissolved in tetrahydrofuran (20 mL) at room temperature. Hydrazine hydrate (190 mg, 5.94 mmol) was added to the reaction solution, and the reaction mixture was stirred at room temperature for 2 hours. Liquid chromatography-mass spectrometry (LC-MS) was used to monitor the depletion of the starting materials. The solvent in the reaction solution was evaporated under reduced pressure to obtain the reaction residue. This residue was further purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a colorless oily substance, which was the target compound T2h-b (500 mg, yield 45.35%).

[0597] LC-MS(m / z,C7H9NO2)=140.2[(M+H)] + .

[0598] 1 H NMR (400MHz, CD2OD-d6) δ10.1(bs,1H),7.42(m,2H),6.73(m,2H),6.25(bs,2H),4.58(s,2H).

[0599] Steps 3-4: Synthesize compound T2h:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-hydroxybenzyl)oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-hydroxybenzyl)oxime

[0600] Compounds T2a-a (77 mg, 0.15 mmol) and T2h-b (105 mg, 0.75 mmol) were dissolved in dimethyl sulfoxide (1 mL) at room temperature. The reaction mixture was stirred at room temperature for 2 hours, and liquid chromatography-mass spectrometry (LC-MS) was used to monitor the complete consumption of the starting materials, yielding a reaction mixture containing compound T2h-c.

[0601] Trifluoroacetic acid (TFA, 1 mL) was then added to the reaction solution, and the reaction was carried out at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS / MS) was used to monitor the complete consumption of the initial reactants. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. This crude product was then subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2h (2.7 mg, 0.0051 mmol, yield 4.28% after preparative purification).

[0602] LC-MS(m / z,C28H23FN4O6)=531.4[(M+H)] + .

[0603] 1 HNMR(400MHz,DMSO-d6)δ8.94(s,1H),7.81(m,1H),7.69-7.60(m,2H),7.59-7.48(m,1H),7.26–7.19(m,2H),6.89-6.85(m,1H) ),6.86-6.82(m,1H),6.47(s,1H),6.21(s,2H),5.42(s,2H),5.36(s,2H),5.26(s,2H),1.89-1.82(m,2H),0.89-0.86(m,3H).

[0604] Examples 1-10: Synthesis of compound T2i

[0605] Step 1: Synthesize compound T2i-a:(S)-(11-(((allyloxy)imino)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0606] Compound T2a-a (200 mg, 0.39 mmol) and 1-(aminooxy)-2-propene (CAS RN: 6542-54-7; 28.69 mg, 0.39 mmol) were dissolved in dimethyl sulfoxide (4 mL) at room temperature. The reaction mixture was stirred at room temperature for 2 hours, and liquid chromatography-mass spectrometry (LC-MS) was used to monitor the complete consumption of the starting materials. The reaction mixture was then directly subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2i-a (150 mg, yield 67.68%).

[0607] LC-MS(m / z,C29H29FN4O7)=565.2[(M+H)] + .

[0608] 1 H NMR(400MHz,DMSO-d6)δ9.54(s,1H),9.03(s,1H),8.89(m,1H),7.96(m,1H),7.28(s,1H),6.50(s,1H),6.16 (m,1H),5.59–5.28(m,4H),5.25(s,2H),4.86(m,2H),2.04–1.72(m,2H),1.52(s,9H),0.88(t,J=7.3Hz,3H).

[0609] Step 2: Synthesize compound T2i:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-allyl oxime,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-allyl oxime

[0610] Compound T2i-a (150 mg, 0.27 mmol) was dissolved in dichloromethane (3 mL) at room temperature. Trifluoroacetic acid (TFA, 1 mL) was then added to the reaction solution, and the reaction was carried out at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS) was used to monitor the complete consumption of the starting materials. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. This crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T2i (5.32 mg, 0.0011 mmol, yield 4.2% after preparative purification).

[0611] LC-MS(m / z,C24H21FN4O5)=465.0[(M+H)] + .

[0612] 1 H NMR (400MHz, DMSO-d6) δ8.93(s,1H),7.80(d,J=12.2Hz,1H),7.61(d,J=9.5Hz,1H),7.20(s,1H),6.47(s,1H),6.22(s,2H) ,6.16–6.06(m,1H),5.49-5.33(m,4H),5.22(s,2H),4.85(dt,J=5.8,1.4Hz,2H),1.92–1.81(m,2H),0.88(t,J=7.3Hz,3H).

[0613] Examples 1-11: Synthesis of compound toxin T2j

[0614] Step 1: Synthesize compound T2j-a: tert-butyl(3-formyl-4-nitrophenyl)carbamate

[0615] At room temperature, to a 200 mL toluene solution containing dissolved 5-bromo-2-nitrobenzaldehyde (CAS RN: 20357-20-410.00 g, 43.47 mmol), tert-butyl carbamate (6.47 g, 55.21 mmol), dibenzylacetone dipalladium (CAS RN: 51364-51-3; 2.0 g, 2.19 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (CAS RN: 564483-18-7; 4.35 g, 9.13 mmol), and cesium carbonate (29.18 g, 89.56 mmol) were added sequentially. The reaction mixture was protected with nitrogen and stirred overnight at 90°C. After the reaction was complete, the mixture was cooled to room temperature and then quenched with 200 mL of water. After separating the organic and aqueous phases in the reaction solution, the aqueous phase was extracted three times with ethyl acetate (200 mL × 3). All organic phases were combined and washed three times with saturated brine (300 mL × 2). After drying with anhydrous sodium sulfate, the organic solvent in the organic phase was evaporated under reduced pressure. The obtained residue was purified by preparative normal-phase column chromatography (PE / EA) to obtain a yellow solid, which was compound T2j-a (10.3 g, 38.68 mmol, reaction yield 88.98%).

[0616] LC-MS(m / z,C12H14N2O5)=267.2[M+H] + .

[0617] 1H NMR (400MHz, DMSO-d6) δ10.30 (s, 1H), 10.29 (s, 1H), 8.18 (d, J = 8.0Hz, 1H), 7.95 (m, 1H), 7.82 (m, 1H), 1.51 (s, 9H).

[0618] Step 2: Synthesize compound T2j-b: tert-butyl(4-amino-3-formylphenyl)carbamate

[0619] At room temperature, iron powder (7.72 g, 138.21 mmol) and ammonium chloride (2.99 g, 55.98 mmol) were added sequentially to a mixed solution of ethanol (120 mL) and water (30 mL) containing compound T2j-a (9.2 g, 34.55 mmol). After the addition was complete, the reaction mixture was heated to 80 °C and stirred for 1 hour. The reaction solution was cooled to room temperature and filtered to remove excess iron powder. The resulting filtrate was extracted three times with ethyl acetate (50 mL × 3). The resulting organic phase was washed twice with saturated brine (30 mL × 2), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain the crude product. The crude product was purified by preparative normal-phase column chromatography (PE:EA = 1:0-4:1) to obtain a yellow solid, which was compound T2j-b (4.2 g, 17.70 mmol, reaction yield 51.23%).

[0620] LC-MS(m / z,C12H16N2O3)=237.2[M+H] + .

[0621] 1 HNMR (400MHz, DMSO-d6) δ9.76 (s, 1H), 9.06 (s, 1H), 7.66 (s, 1H), 7.28 (m, 1H), 6.86 (s, 2H), 6.69 (d, J = 8.0Hz, 1H), 1.46 (s, 9H).

[0622] Step 3: Synthesize compound T2j-c:(S)-(4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0623] At room temperature, (S)-4-ethyl-4-hydroxy-7,8-dihydro-1H-pyrano[3,4-f]indolizine-3,6,10(4H)-trione (CAS RN: 110351-94-5; 2.21 g, 8.40 mmol) and p-toluenesulfonic acid (130 mg, 0.75 mmol) were added sequentially to a toluene solution containing compound T2j-b (1.94 g, 8.21 mmol). After the addition was complete, the reaction solution was heated to 110 °C and stirred for 2 hours. After the reaction solution was cooled to room temperature, the organic solvent was evaporated under reduced pressure to obtain the reaction residue. The crude product, a brown solid obtained after washing the reaction residue with methyl tert-butyl ether, was compound T2j-c (2.2 g, 4.74 mmol, reaction yield 57.75%).

[0624] LC-MS(m / z,C25H25N3O6)=464.2[(M+H)] + .

[0625] 1 H NMR (400MHz, DMSO-d6) δ9.87(s,1H),8.54(s,1H),8.27(s,1H),8.06(d,J=8.0Hz,1H),7.82(m,1H),7.2 8(s,1H),6.50(s,1H),5.42(s,2H),5.24(s,2H),1.90-1.81(m,2H),1.53(s,9H),0.88(t,J=8.0Hz,3H).

[0626] Step 4: Synthesize compound T2j-d:(S)-(4-ethyl-4-hydroxy-11-hydroxymethyl-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0627] At room temperature, ferrous sulfate heptahydrate (780 mg, 2.81 mmol) and 7% dilute sulfuric acid (2.1 mL) were added sequentially to a methanol solution (210 mL) containing compound T2j-c (2.1 g, 4.53 mmol). The reaction mixture was heated to 65°C and stirred for 30 minutes. Then, 30% hydrogen peroxide aqueous solution (3.6 mL) was added, and stirring was continued at 65°C for another 30 minutes. After cooling the reaction mixture to room temperature, it was poured directly into ice water (150 mL). After standing for 1 hour, the yellow solid obtained by filtering the ice water mixture was the target compound T2j-d (1.0 g, 2.02 mmol, reaction yield 44.59%).

[0628] LC-MS(m / z,C26H27N3O7)=494.4[M+H] + .

[0629] 1 HNMR(400MHz,DMSO-d6)δ9.87(s,1H),8.32(s,1H),8.06(d,J=4.0Hz,1H),7.84(dd,J=8.0,4.0Hz,1H),7.28(s,1H),6.50(s,1H) ,5.80(t,J=4.0Hz,1H),5.42(s,2H),5.39(s,2H),5.16(d,J=4.0Hz,2H),1.90-1.83(m,2H),1.53(s,9H),0.88(t,J=8.0Hz,3H).

[0630] Step 5: Synthesize compound T2j-e:(S)-(4-ethyl-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0631] Under anhydrous conditions at room temperature, an anhydrous dimethyl sulfoxide (DMSO) solution containing compound T2j-d (550 mg, 1.11 mmol) was mixed with Dysmartin oxidant (1.41 g, 3.33 mmol). The reaction mixture was stirred at room temperature for 30 minutes, and the insoluble solids were filtered off. Methoxyamine hydrochloride (278.85 mg, 3.34 mmol) was added to the reaction mixture at room temperature, and the reaction was stirred for another hour. The reaction mixture was purified directly by reversed-phase column chromatography (ACN / H2O, 0.1% FA) without any further treatment. The resulting yellow solid was compound T2j-e (222 mg, 0.42 mmol, two-step yield 37.83%).

[0632] LC-MS(m / z,C27H28N4O7)=521.4[M+H] + .

[0633] 1 H NMR(400MHz,DMSO-d6)δ9.92(s,1H),8.89-8.86(m,1H),8.67-8.59(m,1H),8.10-8.05(m,1H),7.89-7.89(m,1H),7.26(s ,1H),6.48(brs,1H),5.42(s,2H),5.26-5.23(m,2H),4.15(s,3H),1.91-1.84(m,2H),1.54(s,9H).0.90(t,J=7.2Hz,3H).

[0634] Step 6: Synthesize compound T2j:(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-methyl oxime,(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-methyl oxime

[0635] Under nitrogen protection at room temperature, trifluoroacetic acid (1 mL) was added to an anhydrous dichloromethane (3 mL) solution containing compound T2j-e (60 mg, 0.12 mmol). After stirring the reaction solution at room temperature for 2 hours, the trifluoroacetate obtained by evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2j (13 mg, 0.031 mmol, yield of 25.83% after preparative purification).

[0636] LC-MS(m / z,C22H20N4O5)=421.2[M+H] + .

[0637] 1 H NMR(400MHz,DMSO-d6+2%deuterated water)δ8.92(s,1H),7.90(d,J=8.8Hz,1H),7.34-7.30(m,2H),7.21(s,1H),5. 40(s,2H),5.26(s,2H),4.11(s,3H),1.87-1.83(m,2H),0.87(t,J=7.2Hz,3H).

[0638] Examples 1-12: Synthesis of compound T2k

[0639] Step 1: Synthesize compound T2k-a:(S)-(11-((ethoxyimino)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0640] Under anhydrous conditions at room temperature, an anhydrous dimethyl sulfoxide (5 mL) solution containing compound T2j-d (250 mg, 0.51 mmol) was mixed with Dysmart oxidant (430 mg, 1.01 mmol). The reaction mixture was stirred at 30°C for 1 hour, and the insoluble solids were filtered off. Ethoxyamine hydrochloride (74.4 mg, 0.76 mmol) was added to the reaction mixture at room temperature, and the mixture was stirred at 30°C for another hour. The reaction mixture was purified directly by reversed-phase column chromatography (ACN / H2O, 0.1% FA) without any further treatment. The resulting brown solid was compound T2k-a (222 mg, 0.42 mmol, two-step yield 37.83%).

[0641] LC-MS(m / z,C28H30N4O7)=535.0[M+H] + .

[0642] 1 H NMR(400MHz,DMSO-d6)δ9.91(s,1H),8.88(s,1H),8.67(s,1H),8.09-8.07(m,1H),7.88-7.85(m,1H),7.27(s,1H),6.50(s,1H) ,5.41(s,2H),5.26(s,2H),4.41(q,J=7.2Hz,2H),1.92-1.82(m,2H),1.54(s,9H),1.41(t,J=7.2Hz,3H),0.89(t,J=8.0Hz,3H).

[0643] Step 2: Synthesize compound T2k:(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-ethyl oxime,(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-ethyl oxime

[0644] At room temperature, trifluoroacetic acid (2 mL) was added to a solution of dichloromethane (6 mL) containing compound T2k-a (120 mg, 0.22 mmol). After stirring the reaction solution at room temperature for 2 hours, the trifluoroacetate obtained by evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2k (35.0 mg, 0.08 mmol, yield of 36.6% after preparative purification).

[0645] LC-MS(m / z,C23H22N4O5)=435.0[M+H] + .

[0646] 1 H NMR(400MHz,DMSO-d6)δ8.91(s,1H),7.90(d,J=8.8Hz,1H),7.35-7.30(m,2H),7.19(s,1H),6.46(s,1 H),6.10(s,2H),5.40(s,2H),5.26(s,2H),4.37(q,J=6.9Hz,2H),1.88-1.83(m,2H),1.39(t,J=6.9Hz 3H),0.88(t,J=7.2Hz 3H).

[0647] Examples 1-13: Synthesis of compound T2l

[0648] Step 1: Synthesize compound T2l-a:(S)-(4-ethyl-4-hydroxy-11-((isopropoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0649] Under anhydrous conditions at room temperature, anhydrous dimethyl sulfoxide (CASRN: 67-68-5, 5 ml) containing compound T2j-d (250 mg, 0.51 mmol) was added to a solution of Dysmart oxidant (430 mg, 1.01 mmol). The reaction mixture was stirred at 30°C for 1 hour, and the insoluble solids were filtered off. Isopropyl hydroxylamine hydrochloride (74.4 mg, 0.76 mmol) was added to the reaction mixture at room temperature, and the mixture was stirred at 30°C for another hour. The reaction mixture was purified directly by reversed-phase column chromatography (ACN / H2O, 0.1% FA) without any further treatment. The resulting brown solid was compound T2l-a (100 mg, 0.18 mmol, reaction yield 35.7%).

[0650] LC-MS (m / z, C29H32N4O7)=549.0[M+H]+.

[0651] 1H NMR (400MHz, DMSO-d6) δ9.92(s,1H),8.87(s,1H),8.72(s,1H),8.09(d,J=9.2Hz,1H),7.84(d,J=10.0Hz,1H),7.27(s,1H),6.5(b s,1H),5.41(s,2H),5.29(s,2H),4.65-4.62(m,1H),1.91-1.83(m,2H),1.54(s,9H),1.41(d,J=6.0Hz,6H),0.88(t,J=7.0Hz,3H).

[0652] Step 2: Synthesize compound T2l:(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-isopropyl oxime,(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-isopropyl oxime

[0653] At room temperature, trifluoroacetic acid (2 mL) was added to a solution of dichloromethane (CAS RN: 75-09-2; 6 mL) containing compound T2l-a (100 mg, 0.18 mmol). After stirring the reaction solution at room temperature for 2 hours, the trifluoroacetate obtained by evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2l (35.0 mg, 0.078 mmol, yield 43.3% after preparative purification).

[0654] LC-MS(m / z,C24H24N4O5)=449.0[M+H] + .

[0655] 1H NMR(400MHz, DMSO-d6)δ8.88(s,1H),7.90(d,J=9.2Hz,1H),7.35-7.29(m,2H),7.19(s,1H),6.46(s,1H),6.08(s, 2H), 5.40 (s, 2H), 5.25 (s, 2H), 4.63-4.57 (m, 1H), 1.89-1.82 (m, 2H), 1.39 (d, J = 6.4Hz, 6H), 0.88 (t, J = 7.4Hz, 3H).

[0656] Examples 1-15: Synthesis of compound T2m

[0657] Step 1: Synthesize compound T2m-a:(S)-(11-((tert-butoxyimino)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate, tert-butyl(S)-(11-((tert-butoxyimino)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate

[0658] Under anhydrous conditions at room temperature, anhydrous dimethyl sulfoxide (3 mL) containing compound T2j-d (200 mg, 0.41 mmol) was added to a solution of Dysmart oxidant (343.7 mg, 0.82 mmol). The reaction mixture was stirred at 30°C for 1 hour, and the insoluble solids were filtered off. o-tert-butylhydroxylamine hydrochloride (74.4 mg, 0.76 mmol) was added to the reaction mixture at room temperature, and the mixture was stirred at 30°C for another 1 hour. The reaction mixture was purified directly by reversed-phase column chromatography (ACN / H2O, 0.1% FA) without any further treatment. The resulting brown solid was compound T2m-a (100 mg, 0.18 mmol, reaction yield 43.98%).

[0659] LC-MS(m / z,C30H34N4O7)=563.4[M+H] + .

[0660] 1H NMR (400MHz, DMSO-d6) δ9.92(s,1H),8.88(s,1H),8.80(s,1H),8.12(d,J=9.2Hz,1H),7.84-7.82(m,1H),7.28(s, 1H), 6.50 (bs, 1H), 5.41 (s, 2H), 5.34 (s, 2H), 1.93-1.81 (m, 2H), 1.53 (s, 9H), 1.47 (s, 9H), 0.88 (t, J = 7.2Hz, 3H).

[0661] Step 2: Synthesize compound T2m:(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(tert-butyl)oxime

[0662] At room temperature, trifluoroacetic acid (2 mL) was added to a solution of dichloromethane (6 mL) containing compound T2m-a (100 mg, 0.18 mmol). After stirring the reaction solution at room temperature for 1 hour, the trifluoroacetate obtained by evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2m (60.0 mg, 0.13 mmol, yield 71.4% after preparative purification).

[0663] LC-MS (m / z, C25H26N4O5)=463.2[M+H]+.

[0664] 1H NMR(400MHz, DMSO-d6)δ8.88(s,1H),7.90(d,J=12.0Hz,1H),7.34-7.31(m,2H),7.20(s,1H),6.47(s ,1H),6.06(s,2H),5.40(s,2H),5.27(s,2H),1.90-1.83(m,2H),1.45(s,9H),0.88(t,J=8.0Hz,3H).

[0665] Examples 1-16: Synthesis of compound T2n

[0666] Step 1: Synthesize compound T2n-a:(S)-(4-ethyl-4-hydroxy-11-(((2-methoxyethoxy)imino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0667] Under anhydrous conditions at room temperature, a solution of anhydrous dimethyl sulfoxide (5 ml) containing compound T2j-d (250 mg, 0.51 mmol) was added to a solution of Dysmart oxidant (93.69 mg, 1.02 mmol). The reaction mixture was stirred at 30°C for 1 hour, and the insoluble solids were filtered off. O-(2-methoxy-ethyl)-hydroxylamine (CAS RN 39684-28-1; 74.4 mg, 0.76 mmol) was added to the reaction mixture at room temperature, and the mixture was stirred at 30°C for another 1 hour. The reaction mixture was purified directly by reversed-phase column chromatography (ACN / H2O, 0.1% FA) without any further treatment. The resulting brown solid was the target compound T2n-a (97.0 mg, 0.17 mmol, reaction yield 33.3%).

[0668] LC-MS(m / z,C29H32N4O8)=565.0[M+H] + .

[0669] 1H NMR (400MHz, DMSO-d6) δ9.95(s,1H),8.96(s,1H),8.74(s,1H),8.13(d,J=9.2Hz,1H),7.90(m,1H),7.29(s,1H),6.5(bs,1H ),5.42(s,2H),5.34(s,2H),4.48(m,2H),3.77(m,2H),3.35(s,3H),1.89-1.83(m,2H),1.54(s,9H),0.89(d,J=7.3Hz,3H).

[0670] Step 2: Synthesize compound T2n:(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-methoxyethyl)oxime,(S)-9-amino-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-11-carbaldehyde O-(2-methoxyethyl)oxime

[0671] At room temperature, trifluoroacetic acid (2 mL) was added to a solution of dichloromethane (6 mL) containing compound T2n-a (97 mg, 0.17 mmol). After stirring the reaction solution at room temperature for 1 hour, the trifluoroacetate obtained by evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T2n (30 mg, 0.06 mmol, yield 35.3% after preparative purification).

[0672] LC-MS(m / z,C24H24N4O6)=465.2[M+H] + .

[0673] 1 H NMR(400MHz, DMSO-d6)δ8.94(s,1H),7.91(d,J=8.0Hz,1H),7.37-7.31(m,2H),7.20(s,1H),6.46(s,1H),6.11(s,2H ),5.41(s,2H),5.27(s,2H),4.46-4.44(m,2H),3.75-3.73(m,2H),3.35(s,3H),1.92-1.81(m,2H),0.89(t,J=6.0Hz 3H).

[0674] Examples 1-17: Synthesis of compound T3a

[0675] Step 1: Synthesize compound T3a-a:(S)-(11-(chloromethyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0676] Compound T1a-e (100 mg, 0.2 mmol) was dissolved in dichloromethane (5 ml) at room temperature. Then, a dichloromethane (1 ml) solution containing thionyl chloride (0.14 ml, 87.5 mg, 0.73 mmol) was added dropwise at room temperature, and stirring continued for 1 hour. The reaction mixture was monitored by liquid chromatography-mass spectrometry until the initial reactants were completely consumed. The yellow substance obtained after evaporating the organic solvent from the reaction mixture under reduced pressure was the target compound T3a-a (80 mg, 0.15 mmol, yield 75%).

[0677] LC-MS(m / z,C26H25ClFN3O6)=530.2[(M+H)] + .

[0678] 1 H NMR (400MHz, DMSO-d6) δ9.48(s,1H),8.48(d,J=8.4Hz,1H),7.95(d,J=12Hz,1H),7.29(s,1H),6.49(s,1 H),5.89(s,2H),5.39(s,2H),5.24(d,J=4.4Hz,2H),1.96-1.82(m,2H),1.54(s,9H),0.91-0.89(m,3H).

[0679] Steps 2-3: Synthesis of toxin T3a:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0680] Compound T3a-a:((S)-(11-(chloromethyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl) tert-butyl carbamate, 80 mg, 0.15 mmol) was dissolved in N,N-dimethylformamide solvent (CAS RN: 68-12-2; 5 mL) at room temperature. N,O-dimethylhydroxylamine (CAS RN: 1117-79-1, 18.4 mg, 0.30 mmol) and N,N-diisopropylethylamine (38.7 mg, 0.3 mmol) were added to the reaction solution, and the mixture was stirred at room temperature for 18 hours. Liquid chromatography-mass spectrometry (LC-MS) was used to monitor the reaction until the initial reactants were completely consumed, yielding a reaction solution containing compound T3a-b.

[0681] Trifluoroacetic acid (1 mL) was added dropwise to the reaction solution, and the mixture was stirred at room temperature for 1 hour. The reaction solution was monitored by liquid chromatography-mass spectrometry (LC-MS / MS) until the initial reactants were completely consumed. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. This crude product was then subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T3a (3.0 mg, 0.0065 mmol, yield 3% after purification).

[0682] LC-MS (m / z, C23H23FN4O5)=455.2[(M+H)]+.

[0683] 1 H NMR (400MHz, DMSO-d6) δ7.76(d,J=12.3Hz,1H),7.46(d,J=9.7Hz,1H),7.21(s,1H),6.47(s,1H),6.13(s,2H),5.4 1(s,2H),5.27(s,2H),4.20(d,J=2.5Hz,2H),3.14(s,3H),2.72(s,3H),1.94–1.80(m,2H),0.88(t,J=7.3Hz,3H).

[0684] Examples 1-18: Synthesis of compound T3b

[0685] Step 1: Synthesize compound T3b:(S)-11-((1,2-oxazinan-2-yl)methyl)-9-amino-4-ethyl-8-fluoro-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-11-((1,2-oxazinan-2-yl)methyl)-9-amino-4-ethyl-8-fluoro-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0686] Compound T1a-e (12.78 mg, 0.025 mmol) was dissolved in dichloromethane (CAS RN: 75-09-2; 5 ml) at room temperature. Phosphorus tribromide (CAS RN: 7789-60-8; 13.5 mg, 0.050 mmol) was added to the reaction solution, and the solution was heated to 40°C and stirred for 16 hours. The reaction residue obtained after evaporating the organic solvent from the reaction solution under reduced pressure was redissolved in dichloromethane (CAS RN: 75-09-2; 1 ml). Then, a solution of N,N-dimethylformamide (CAS RN: 68-12-2; 1 ml) containing [1,2]oxazinline (CAS RN: 36652-42-3; 4.0 mg, 0.046 mmol) and N,N-diisopropylethylamine (CAS RN: 7087-68-5, 0.02 mL, 0.13 mmol) was added sequentially, and the mixture was stirred at room temperature for 10 minutes. Liquid chromatography-mass spectrometry (LC-MS) monitoring confirmed the complete consumption of the initial reactants. The reaction solution was directly subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain compound T3b (3.0 mg, 0.0062 mmol, yield of 13.58% after preparative purification).

[0687] LC-MS(m / z,C25H25FN4O5)=481.0[M+H] + .

[0688] 1HNMR(400MHz,DMSO-d6)δ7.76(d,J=12.0Hz,1H),7.41(d,J=12.0Hz,1H),7.20(s,1H),6.46(s,1H),6.11(s ,2H),5.40(s,2H),5.28(s,2H),4.22(s,2H),3.73(s,2H),2.96(brs,2H),1.85-1.79(m,2H),1.78-1.76(m 2H), 1.52-1.49 (m 2H), 0.87 (t, J=8.0Hz, 3H).

[0689] Examples 1-18: Synthesis of compound T3c

[0690] Step 1: Synthesize compound T3c-a:(S)-(11-(chloromethyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0691] Under anhydrous conditions at room temperature, thionyl chloride (CAS RN: 7719-09-7; 0.028 mL, 0.38 mmol) was added to a solution of dichloromethane (10 mL) containing compound T2j-d (200 mg, 0.41 mmol), and the mixture was reacted at room temperature for 1 hour. After adding dichloromethane (10 mL) and toluene (1 mL) to the reaction solution and evaporating the organic solvent under reduced pressure, the resulting brown solid was compound T3c-a (200 mg crude product), which was directly used in the next reaction step.

[0692] LC-MS (m / z, C 26 H 26 ClN3O6)=512.2[(M+H)] + .

[0693] Step 2: Synthesize compound T3c-b:(S)-(4-ethyl-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0694] Compound T3a-a (200 mg crude) was dissolved in N,N-dimethylformamide solvent (CAS RN: 68-12-2; 5 mL) at room temperature. Methoxymethylamine (CAS RN: 1117-97-1; 53.69 mg, 0.88 mmol) and N,N-diisopropylethylamine (CAS RN: 7087-68-5; 0.15 mL, 0.88 mmol) were added to the reaction solution, and the mixture was stirred at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS) was used to monitor the reaction until the initial reactants were completely consumed. The reaction solution was then directly subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T3a-b (30 mg, 0.056 mmol, two-step reaction yield 13.41%).

[0695] LC-MS(m / z,C28H32N4O7)=537.4[M+H] + .

[0696] 1 H NMR (400MHz, DMSO-d6) δ9.89(s,1H),8.09(d,J=12.0Hz,1H),7.92(d,J=8.0Hz1H),7.83(d,J=12.0Hz,1H),7.26(s,1H),6.51(b s,1H),5.42(s,2H),5.27(s,1H),4.13(s,2H),3.22(s,3H),2.71(s,3H),1.89-1.85(m,2H),1.54(s,9H),0.88(t,J=8.0Hz,3H).

[0697] Step 3: Synthesize compound T3c:(S)-9-amino-4-ethyl-4-hydroxy-11-((methoxy(methyl)amino)methyl)1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-9-amino-4-ethyl-4-hydroxy-11-((methoxy(methyl)amino)methyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0698] Compound T3c-b (30 mg, 0.056 mmol) was dissolved in dichloromethane (CAS RN: 75-09-2; 1 mL) at room temperature. Trifluoroacetic acid (CAS RN: 76-05-1, 0.3 mL) was added dropwise to the reaction solution, and the mixture was stirred for 1 hour at room temperature. The reaction solution was monitored by liquid chromatography-mass spectrometry until the initial reactants were completely consumed. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T3c (2.59 mg, 0.0059 mmol, yield of 10.53% after preparative purification).

[0699] LC-MS(m / z,C23H24N4O5)=437.2[M+H] + .

[0700] 1 H NMR(400MHz,DMSO-d6+2%deuterated water)δ7.86(d,J=12.0Hz,1H),7.27(m,1H),7.20(s,2H),5.40(s,2H),5.26(s,2H ), 4.18 (s, 2H), 3.14 (s, 3H), 2.71 (s, 3H), 1.89-1.84 (m, 2H), 0.88 (t, J = 7.2Hz, 3H).

[0701] Examples 1-19: Synthesis of compound T1c

[0702] (S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-(morpholinomethyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione+(Zymworks Inc.)

[0703] (S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-(morpholinomethyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0704] Steps 1-2: Synthesize compound T1c:(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-(morpholinomethyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-9-amino-4-ethyl-8-fluoro-4-hydroxy-11-(morpholinomethyl)-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0705] Compound T3a-a (100 mg, 0.19 mmol) was dissolved in N,N-dimethylformamide solvent (CAS RN: 68-12-2; 5 mL) at room temperature. Morpholine (CAS RN: 110-91-8, 16.44 mg, 0.19 mmol) was added to the reaction solution, and the mixture was stirred at room temperature for 18 hours. The reaction solution was monitored by liquid chromatography-mass spectrometry until the starting materials were completely consumed, yielding a reaction solution containing compound T1c-a.

[0706] Then, trifluoroacetic acid (CAS RN: 76-05-1, 1 mL) was added to the reaction solution. The reaction solution was monitored by liquid chromatography-mass spectrometry (LC-MS) until the initial reactants were completely consumed. The organic solvent in the reaction solution was evaporated under reduced pressure to obtain crude trifluoroacetate. This crude product was then subjected to preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound T1c (10.0 mg, 10% yield after preparative purification).

[0707] LC-MS(m / z,C25H25FN4O5)=481.2[(M+H)] + .

[0708] 1 H NMR (400MHz, DMSO-d6) δ7.75(d,J=12.4Hz,1H),7.50(d,J=9.8Hz,1H),7.20(s,1H),6.47(s,1H),6.10(s,2H),5.41 (s,2H),5.28(s,2H),3.91(s,2H),3.58(t,J=4.5Hz,4H),2.47(m,4H),1.85(p,J=7.0Hz,2H),0.87(t,J=7.3Hz,3H).

[0709] Examples 1-20: Synthesis of compound T4a

[0710] Step 1: Synthesize compound T4a-a: (S)-(11-bromomethyl-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0711] At 0°C, dibromo sulfoxide (CAS RN: 507-16-4; 304.79 mg, 1.47 mmol) and N,N-dimethylformamide (CAS RN: 68-12-2, 2 drops) were added to a 5 mL solution of dichloromethane containing compound T1a-e (500 mg, 0.98 mmol) and stirred for 2 hours. The reaction mixture was monitored by liquid chromatography-mass spectrometry until the initial reactants were completely consumed. The yellow substance obtained after evaporating the organic solvent from the reaction mixture under reduced pressure was compound T4a-a (300 mg, 0.52 mmol, reaction yield 53.43%).

[0712] LC-MS(m / z,C26H25BrFN3O6)=573.8[M+H] + .

[0713] 1H NMR(400MHz,DMSO-d6)δ9.59(s,1H),8.66(s,J=8.0Hz,1H),8.02(d,J=12.0Hz,1H),7.30(s,1H),6.54 (s,1H),5.44(s,2H),5.32(s,2H),5.22(s,2H),1.90-1.82(m,2H),1.53(s,9H),0.87(t,J=8.0Hz,3H).

[0714] Step 2: Synthesize compound T4a-b:(S)-(11-(((1,3-dioxoisoindolin-2-yl)oxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate, tert-butyl(S)-(11-(((1,3-dioxoisoindolin-2-yl)oxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate

[0715] At room temperature, N-hydroxyphthalimide (CAS RN: 524-38-9; 170.40 mg, 1.04 mmol) and N,N-diisopropylethylamine (CAS RN: 7087-68-5; 135.01 mg, 1.04 mmol) were added to a solution of N,N-dimethylformamide (CAS RN: 7087-68-5; 135.01 mg, 1.04 mmol) containing compound T4a-a (200 mg, 0.35 mmol), and the mixture was stirred at room temperature for two hours. The reaction solution was purified directly by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting pale yellow solid was the target compound T4a-b (120 mg, 0.18 mmol, 52.49%).

[0716] LC-MS(m / z,C34H29FN4O9)=657.4[M+H] + .

[0717] 1H NMR (400MHz, DMSO-d6) δ9.54(s,1H),8.66(d,J=8.4Hz,1H),8.05(d,J=11.7Hz,1H),7.86(s,4H),7.33 (s,1H),6.53(s,1H),5.86(s,2H),5.44(m,4H),1.90–1.83(m,2H),1.52(s,9H),0.88(t,J=7.3Hz,3H).

[0718] Step 3: Compound T4a-c:(S)-(11-((aminooxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate, tert-butyl(S)-(11-((aminooxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate

[0719] At 0°C, hydrazine hydrate (CAS RN: 10217-52-4, 19.71 mg, 0.34 mmol) was added to a methanol (5 mL) solution containing compound T4a-b (110 mg, 0.17 mmol), and the reaction was stirred at 0°C for 1 hour. The reaction solution was purified directly by preparative reversed-phase column chromatography without any further treatment to obtain a yellow solid, which was compound T4a-c (30 mg, 0.06 mmol, reaction yield 34.01%).

[0720] LC-MS(m / z,C26H27FN4O7)=527.0[M+1] + .

[0721] 1 H NMR(400MHz,DMSO-d6)δ9.54(s,1H),8.58(m,1H),8.00(m,1H),7.32(s,1H),6.53(s,1H),5. 44(s,2H),5.39(s,2H),5.27(s,2H),1.92–1.82(m,2H),1.53(s,9H),0.88(t,J=7.3Hz,3H).

[0722] Step 4: Synthesize compound T4a-d:(S)-(11-(((dimethylamino)oxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate, tert-butyl(S)-(11-(((dimethylamino)oxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate

[0723] At room temperature, a solution of compound T4a-c (30 mg, 0.06 mmol) in glacial acetic acid (3 mL) was added sequentially with an aqueous formaldehyde solution (0.1 mL, 35% aqueous solution) and sodium cyanoborohydride (CAS RN: 25895-60-7; 10.74 mg, 0.17 mmol). After stirring, sodium cyanoborohydride (CAS RN: 25895-60-7; 10.74 mg × 2, 0.17 mmol × 2) was added twice at 30 and 60 minutes. At 90 minutes, excess sodium cyanoborohydride was quenched with water, and dichloromethane (50 mL × 2) was added for extraction. The separated organic phase was dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to obtain compound T4a-d (20 mg, 0.04 mmol, reaction yield 63.29%).

[0724] LC-MS(m / z,C28H31FN4O7)=555.0[M+1] + .

[0725] 1 H NMR(400MHz,DMSO-d6)δ9.51(s,1H),8.66(m,1H),7.98(m 1H),7.30(s,1H),6.51(s,1H),5.43(s,2H),5.35(s,2H),5.21(s,2H),2.54(s,6H),1.87–1.83(m,2H),1.53(s,9H),0.86(t,J=7.3Hz,3H).

[0726] Step 5: Synthesize compound T4a:(S)-9-amino-11-(((dimethylamino)oxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-9-amino-11-(((dimethylamino)oxy)methyl)-4-ethyl-8-fluoro-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0727] At room temperature, trifluoroacetic acid (CAS.RN:76-05-1, 1 ml) was added to a solution of dichloromethane (CAS RN:75-09-2; 1 ml) containing compound T4a-d (20 mg, 0.04 mmol), and the mixture was stirred for two hours at room temperature. The reaction residue obtained after evaporating the solvent under reduced pressure was purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19 × 250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound T4a (5 mg, 0.01 mmol, reaction yield 30.51%).

[0728] LC-MS (m / z, C23H23FN4O5)=455.2[M+H]+.

[0729] 1 H NMR (400MHz, DMSO-d6) δ7.77(d,J=12.4Hz,1H),7.35(d,J=9.6Hz,1H),7.21(s,1H),6.46(s,1H),6.17 (s,2H),5.41(s,2H),5.28(s,2H),5.10(s,2H),2.51(s,6H),1.91–1.76(m,2H),0.87(t,J=7.3Hz,3H).

[0730] Examples 1-21: Synthesis of compound T4b

[0731] Step 1: Synthesize compound T4b-a:(S)-(11-(bromomethyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0732] At 0°C, dibromo sulfoxide (CAS RN: 5 ml; 400 mg, 0.81 mmol) and N,N-dimethylformamide (CAS RN: 68-12-2, 2 drops) were added sequentially to a solution of compound T2j-d (400 mg, 0.81 mmol) in dichloromethane (CAS RN: 75-09-2). The reaction mixture was stirred at 0°C for 2 hours, and then quenched with water. The reaction mixture was extracted twice with dichloromethane solvent (CAS RN: 75-09-2; 50 ml × 2). The separated organic phase was dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to obtain a yellow solid, which was compound T4b-a (380 mg, 0.68 mmol, reaction yield 84.37%).

[0733] LC-MS(m / z,C26H26BrN3O6)=556.2[M+H] + .

[0734] 1 H NMR(400MHz,DMSO-d6)δ9.98(s,1H),8.49(s,1H),8.25-8.02(m,2H),7.28(s,1H),6.49(s,1H) ,5.43(s,2H),5.31(s,2H),5.14(s,2H),1.89-1.85(m,2H),1.53(s,9H),0.88(t,J=6.0Hz,3H).

[0735] Step 2: Synthesize compound T4b-b:(S)-(11-(((1,3-dioxoisoindolin-2-yl)oxy)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate, tert-butyl(S)-(11-(((1,3-dioxoisoindolin-2-yl)oxy)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate

[0736] At room temperature, N-hydroxyphthalimide (CAS RN: 524-38-9; 200.54 mg, 1.23 mmol) and N,N-diisopropylethylamine (238.33 mg, 1.84 mmol) were added to N,N-dimethylformamide (CAS RN: 68-12-2; 6 ml) containing dissolved compound T4b-a (380 mg, 0.68 mmol). The reaction mixture was stirred at room temperature for 2 hours, and the solvent was evaporated under reduced pressure to obtain the reaction residue. This residue was directly purified by preparative reversed-phase column chromatography (column: Welch-Ultimate-C18-10 μm-21.2 × 150 mm, mobile phase: A: 0.1% TFA / H2O, B: ACN). The resulting yellow solid was compound T4b-b (170 mg, 0.27 mmol, reaction yield 39.10%).

[0737] LC-MS(m / z,C34H30N4O9)=639.4[M+H] + .

[0738] 1 H NMR(400MHz,DMSO-d6)δ9.93(s,1H),8.49(s,1H),8.13(d,J=8.0Hz,1H),7.90-7.86(m,5H),7.31(s,1H),6 .51(s,1H),5.85(s,2H),5.46(s,2H),5.43(s,2H),1.93-1.84(m,2H),1.53(s,9H),0.89(t,J=6.0Hz,3H).

[0739] Step 3: Synthesize compound T4b-c:(S)-(11-((aminooxy)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate.

[0740] Hydrazine hydrate (CAS RN: 10217-52-4; 23.0 mg, 0.46 mmol) was added to a methanol (CAS RN: 67-56-1; 5 ml) solution containing compound T4b-b (150 mg, 0.23 mmol) at 0°C. The reaction was continued with stirring at 0°C for 1 hour, and the solvent was evaporated under reduced pressure to obtain the reaction residue. This residue was directly purified by preparative reversed-phase column chromatography (column: Welch-Ultimate-C18-10 μm-21.2 × 150 mm, mobile phase: A: 0.1% TFA / H2O, B: ACN). The resulting yellow solid was compound T4b-c (40 mg, 0.079 mmol, reaction yield 34.34%).

[0741] LC-MS(m / z,C26H28N4O7)=509.4[M+1] + .

[0742] 1 HNMR(400MHz,DMSO-d6)δ9.88(s,1H),8.43(s,1H),8.09(d,J=8.0Hz,1H),7.86(dd,J=8.0Hz,4.0Hz,1H),7.29(s,1H),6 .50(s,1H),6.39(s,2H),5.43(s,2H),5.38(s,2H),5.19(s,2H),1.90-1.83(m,2H),1.53(s,9H),0.88(t,J=8.0Hz,3H).

[0743] Step 4: Synthesize compound T4b-d:(S)-(11-(((dimethylamino)oxy)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate, tert-butyl(S)-(11-(((dimethylamino)oxy)methyl)-4-ethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)carbamate

[0744] At room temperature, formaldehyde aqueous solution (CAS RN: 50-00-0; 0.5 ml, 35% aqueous solution) and sodium cyanoborohydride (CAS RN: 25895-60-7; 10.74 mg, 0.17 mmol) were added to glacial acetic acid (CAS RN: 64-19-7; 2 ml) containing dissolved compound T4b-c (40 mg, 0.079 mmol). Sodium cyanoborohydride (CAS RN: 25895-60-7; 10.74 mg × 2, 0.17 mmol × 2) was added twice, after reacting at room temperature for 30 minutes and 1 hour. After 1.5 hours of reaction, unreacted sodium cyanoborohydride was quenched with water. The reaction solution was extracted with dichloromethane (CAS RN: 75-09-2; 50 ml × 2). After separation of the organic phase, the organic phase was dried with anhydrous ammonium sulfate, and the solvent was evaporated under reduced pressure to obtain the reaction residue. The concentrated yellow solid is compound T4b-d (40 mg, 0.07 mmol, reaction yield 88.45%).

[0745] LC-MS (m / z, C28H32N4O7)=537.4[(M+1)]+.

[0746] 1 H NMR(400MHz, DMSO-d6)δ9.90(s,1H),8.49(s,1H),8.09(d,J=8.0Hz,1H),7.89-7.87(m,1H),7.28(s,1H),6.50( s,1H),5.42(s,2H),5.27(s,2H),5.18(s,2H),2.54(s,6H),1.91–1.83(m,2H),1.53(s,9H),0.90-0.84(m,3H).

[0747] Step 5: Synthesize compound T4b:(S)-9-amino-11-(((dimethylamino)oxy)methyl)-4-ethyl-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione,(S)-9-amino-11-(((dimethylamino)oxy)methyl)-4-ethyl-4-hydroxy-1,12-dihydro-14H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14(4H)-dione

[0748] At room temperature, trifluoroacetic acid (CAS.RN:76-05-1; 1 mL) was added to dichloromethane (CAS RN:75-09-2; 1 mL) containing compound T4b-d (40 mg, 0.07 mmol). After stirring the reaction solution at room temperature for two hours, the excess solvent trifluoroacetic acid was evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was directly purified by preparative reversed-phase column chromatography (column: Welch-Ultimate-C18-10 μm-21.2 × 150 m, mobile phase: A: 0.1% TFA / H2O, B: ACN). The resulting yellow solid was compound T4b (6.66 mg, 0.015 mmol, yield 21.42% after preparative purification).

[0749] LC-MS (m / z, C23H24N4O5)=437.2[M+1]+.

[0750] 1 H NMR(400MHz,DMSO-d6)δ7.87(d,J=8.0Hz,1H),7.28-7.25(m,1H),7.20(s,1H),7.10(s,1H),6.46(s,1H),6 .04(bs,2H),5.42(s,2H),5.27(s,2H),5.09(s,2H),2.56(s,6H),1.91–1.81(m,2H),0.88(t,J=8.0Hz,3H).

[0751] The compounds of the typical drug D prepared in this embodiment are shown in Table 5B below:

[0752] Table 5B

[0753] Note: The compounds of drug D other than those in Examples 1-1 to 1-21 included in the table above were prepared in a manner similar to that in Examples 1-1 to 1-21.

[0754] Example 2: Preparation of linker toxin compounds

[0755] Example 2.1 Synthesis of LPc-001r: (AstraZeneca, AZ0133)

[0756] The synthesis of LPc-001r(AZ0133) was prepared by following the experimental procedures of WO2021148500 and WO2021148501.

[0757] LC-MS: (m / z,C57H77N7O18):574.6(M+2H) 2+ .

[0758] Example 2.2 Synthesis of LPc-002r:MA-PEG3-GGFG-Toxin T1b (Zymeworks Inc., DL-9, DOI: 10.1158 / 1535-7163.MCT-23-0822);

[0759] The synthesis of LPc-002r followed the experimental procedure outlined in WO2022246576 and was prepared using compound T1b.

[0760] LC-MS (m / z, C48H51FN8O14)=984.0[(M+H)]+.

[0761] Example 2.3 Synthesis of LPc-003r:MA-PEG3-GGFG-Toxin T1a (Zymeworks Inc., DL-11, DOI: 10.1158 / 1535-7163.MCT-23-0822);

[0762] Step 1: Synthesize compound LPc-003r-a: tert-butyl(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate, tert-butyl(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate

[0763] At room temperature, while stirring, BOC-glycine (CAS RN: 4530-20-5, 1.0 g, 5.70 mmol), N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN: 148893-10-1, 3.61 g, 9.51 mmol), and N,N-diisopropylethylamine (CAS RN: 7087-68-5, 2.46 g, 19.01 mmol) were added to an anhydrous N,N-dimethylformamide (CAS RN: 68-12-2; 20 mL) solution containing toxin T1b (1.45 g, 3.80 mmol). The reaction mixture was stirred at room temperature for 16 hours, and the reaction was monitored for completion using liquid chromatography-mass spectrometry (LC-MS / MS). The reaction solution was poured into ice water and allowed to stand for 30 minutes before filtration. The filtered solid was dried and purified by normal-phase column chromatography using SiO2 (methanol / dichloromethane). The resulting brown solid was the compound LPc-003r-a (1.25 g, 2.32 mmol, reaction yield 61.00%).

[0764] LC-MS (m / z, C 27 H 27 FN4O7) = 539.2 [M+H] + .

[0765] 1 H NMR(400MHz,DMSO-d6)δ10.07(s,1H),8.76(d,1H),8.63(s,1H),7.98(d,1H),7.30(s,1H),7.19-7.06(m,1 H),6.51(s,1H),5.42(s,2H),5.21(s,2H),3.91(d,2H),1.90-1.84(m,2H),1.43(s,9H),0.91-0.87(m,3H).

[0766] Step 2: Synthesize compound LPc-003r-b: tert-butyl(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate, tert-butyl(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate

[0767] At room temperature, ferrous sulfate heptahydrate (CAS RN: 7782-63-0; 1.39 g, 5.01 mmol) and sulfuric acid (CAS RN: 7664-93-9; 0.82 g, 8.36 mmol) were added to a 33 mL anhydrous methanol solution containing 1.8 g (3.34 mmol) of compound LPc-003r-a. The reaction mixture was heated to 60°C, and then 30% hydrogen peroxide solution (CAS RN: 7722-84-1; 1.36 g, 40.11 mmol, 30% in water) was slowly added dropwise over 10 minutes. The reaction mixture was stirred at 60°C for 20 minutes, then cooled to room temperature and poured into ice water, where it was allowed to stand for 30 minutes. The brown solid obtained after filtering the ice-water mixture was compound LPc-003r-b (1.36 g, 2.39 mmol, reaction yield 71.56%).

[0768] LC-MS (m / z, C 28 H 29 FN4O8) = 569.2 [M+H] + .

[0769] 1 H NMR(400MHz,DMSO-d6)δ10.14(s,1H),8.84(d,1H),8.00(d,1H),7.31(s,1H),7.19-7.16(m,1H),6.53(s,1 H),5.43(s,2H),5.38(s,2H),5.16(s,2H),3.91(d,2H),1.91-1.83(m,2H),1.42(s,9H),0.90-0.86(m,3H).

[0770] Step 3: Synthesize compound LPc-003r-c: (S)-2-amino-N-(4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)acetamide.

[0771] Trifluoroacetic acid (CAS.RN:76-05-1, 10 mL) was added to anhydrous dichloromethane (30 mL) containing compound LPc-003r-b (1.0 g, 1.76 mmol) at room temperature. After stirring the reaction solution at room temperature for 1 hour, excess organic solvent and trifluoroacetic acid were directly evaporated under reduced pressure to obtain the reaction residue. The residue was purified directly by preparative reversed-phase column chromatography (C18 system, acetonitrile / water (trifluoroacetic acid) system) to obtain a brown solid, which is the trifluoroacetate of compound LPc-003r-c ((S)-2-amino-N-(4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)acetamide, 790 mg, 1.35 mmol, reaction yield 76.7%).

[0772] LC-MS (m / z, C 23 H 21 FN4O6) = 469.2 [M+H] + .

[0773] 1 H NMR(400MHz,DMSO-d6)δ10.71(s,1H),8.90(d,1H),8.17(s,2H),8.09(d,1H),7.33(s,1H),6.52(s,1H), 5.87(s,1H),5.42(s,2H),5.41(s,2H),5.16(s,2H),3.97(s,2H),1.92-1.82(m,2H),0.90-0.86(m,3H).

[0774] Step 4: Synthesize compound LPc-003r-d: (9H-fluoren-9-yl)methyl(2-(2(((S)-1((2-((((S)-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-2-oxoethyl)amino)-1-oxo-3-phenylprop-2-yl)amino)2-oxoethyl)amino)-2-oxoethyl)carbamate, (9H-fluoren-9-yl)methyl(2-((2-(((S)-1-((2) -(((S)-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[ 1,2-b]quinolin-9-yl)amino)-2-oxoethyl)amino)-1-oxo-3-phenylpropan-2-yl)amino)-2-oxoethyl)amino)-2-oxoethyl)carbamate

[0775] At 0°C, N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN:148893-10-1; 454 mg, 1.20 mmol) and N,N-diisopropylethylamine (CAS RN:7087-68-5; 386 g, 2.99 mmol) were added sequentially to an anhydrous dimethyl sulfoxide (CAS RN:67-68-5, 4 mL) solution containing (((9H-fluorene-9-yl)methoxy)carbonyl)glycylglycyl-L-phenylalanine (CAS RN:160036-44-2; 299 mg, 0.6 mmol). After stirring the mixture at 0°C for 30 minutes, compound LPc-003r-c (280 mg, 0.6 mmol) was added. After stirring at 0 degrees Celsius for another half hour, the reaction solution was directly purified by preparative reversed-phase column chromatography (C18 system, acetonitrile / water (trifluoroacetic acid)) to obtain a brown solid, which was compound LPc-003r-d (290 mg, 0.20 mmol, reaction yield 33.54%).

[0776] LC-MS (m / z, C 51 H 46 FN7O 11 = 952.2[M+H] + .

[0777] Step 5: Synthesize compound LPc-003r-e: (S)-2-(2-(2-aminoacetamido)acetamido)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-2-oxoethyl)-3-phenylpropionamide, (S)-2-(2-(2-aminoacetamido) ... tamido)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)-3-phenylpropanamide

[0778] At room temperature, diethylamine (CAS RN: 109-89-7; 57 mg, 0.79 mmol) was added to anhydrous N,N-dimethylformamide (CAS RN: 68-12-2; 4 mL) solution containing compound LPc-003r-d (150 mg, 0.16 mmol). After stirring the reaction solution at room temperature for 2 hours, it was directly purified by reversed-phase chromatography on a C18 column (acetonitrile / water (trifluoroacetic acid) system) to obtain a brown solid, which was compound LPc-003-e (100 mg, 0.13 mmol, reaction yield 87.3%).

[0779] LC-MS (m / z, C 36 H 36 FN7O9)=730.2[M+H] + .

[0780] Step 6: Synthesize compound LPc-003r:(S)-2-(1-(2,5-dioxo-2,5-dihydro-1H-pyrrolo-1-yl)-12,15-dioxo-3,6,9-trioxo-13,16-diazaoctadecane-18-acyl)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-2-oxoethyl)-3-phenylpropionamide,(S)-2-(1-(2,5-dioxo-2,5-dihydro-1H-pyrro l-1-yl)-12,15-dioxo-3,6,9-trioxa-13,16-diazaoctadecan-18-amido)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-(hydroxymethyl)- 3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)-3-phenylpropanamide

[0781] At room temperature, N,N-dimethylformamide (4 mL) containing maleimide-polyethylene glycol-propionic acid (CAS RN: 518044-40-1; 124 mg, 0.41 mmol) was added sequentially to a solution of N,N-dimethylformamide (4 mL) containing maleimide-polyethylene glycol-propionic acid (CAS RN: 518044-40-1; 124 mg, 0.41 mmol) and N,N-diisopropylethylamine (CAS RN: 7087-68-5; 9 mg, 0.69 mmol). After stirring the reaction solution for 10 minutes, compound LPc-003-e (100 mg, 0.14 mmol) was added. After stirring the reaction solution at room temperature for 1 hour, it was directly purified by high performance preparative liquid chromatography (column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound LPc-003r (0 mg, 0.029 mmol, reaction yield 21.1%).

[0782] LC-MS (m / z, C 49 H 53 FN8O 15 = 1013.3[M+H] + .

[0783] Example 2.4 Synthesis of LPc-003x1:MTA-PEG2-GGFG-Toxin T3a;

[0784] Step 1: Synthesize compound LPc-003x1-a:(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate, tert-butyl(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate

[0785] At room temperature, N,N,N',N'-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (HATU, CAS RN:148893-10-1; 418 mg, 1.10 mmol) and N,N-diisopropylethylamine (CAS RN:7087-68-5; 142.20 mg, 1.10 mmol) were added sequentially to a solution of N,N-dimethylformamide (CAS RN:68-12-2; 2 ml) containing dissolved Boc-glycine (CAS RN:4530-20-5; 192 mg, 1.10 mmol) and N,N-diisopropylethylamine (CAS RN:7087-68-5; 142.20 mg, 1.10 mmol). After stirring the reaction solution at room temperature for 30 minutes, compound T3a (100 mg, 0.22 mmol) was added. After stirring the reaction solution at room temperature for 16 hours, the yellow solid obtained by purification using preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) was compound LPc-003x1-a (10mg, 0.016mmol, yield 8.0%).

[0786] LC-MS(m / z,C30H34FN5O8)=612.4[M+H] + .

[0787] Step 2: Synthesize compound LPc-003x1-b:(S)-2-amino-N-(4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)--3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)acetamide,(S)-2-amino-N-(4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)acetamide

[0788] At room temperature, LPc-003x1-a (10 mg, 0.02 mmol) was dissolved in dichloromethane (CAS RN: 75-09-2; 1 ml). Trifluoroacetic acid (CAS RN: 76-05-1; 0.5 ml) was added to the reaction solution, and the mixture was stirred at room temperature for 1 hour. Liquid chromatography-mass spectrometry (LC-MS / MS) was used to monitor the complete consumption of the starting materials. After evaporation of the organic solvent from the reaction solution, crude trifluoroacetate was obtained. This crude product was purified directly by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-003x1-b (8 mg, 0.015 mmol, reaction yield 78.12%).

[0789] LC-MS(m / z,C25H26FN5O6)=512.4[M+H] + .

[0790] Step 3: Synthesize compound LPc-003x1-c: tert-butyl 3-(2-(2-oxoethoxy)ethoxy)propanoate

[0791] At room temperature, pyridine (CAS RN: 110-86-1; 4.31 mL, 53.35 mmol) and Dys-Martin oxidant (CAS RN: 87413-09-0; 10.86 g, 25.61 mmol) were added to a solution of tert-butyl 3-(2-(2-hydroxyethoxy)ethoxy)propionate (CAS RN: 133803-81-3; 5.0 g, 21.34 mmol) dissolved in dichloromethane (CAS RN: 75-09-2; 65 mL) solvent, followed by saturated sodium sulfite solution (65 mL) and saturated sodium bicarbonate solution (65 mL), and the mixture was stirred for 30 minutes to quench the reaction. The organic phase was separated and dried using anhydrous sodium sulfate. The reaction residue was obtained after evaporating the solvent from the organic phase under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate: petroleum ether = 0 to 50%) to obtain a colorless oily substance, which was compound LPc-003x1-c (4.8 g, 20.66 mmol, reaction yield 96.83%).

[0792] 1 H NMR (400MHz, Chloroform-d) δ9.65 (s, 1H), 4.08 (s, 2H), 3.70–3.63 (m, 4H), 3.62–3.58 (m, 2H), 2.44 (t, J = 6.4Hz, 2H), 1.38 (s, 9H).

[0793] Step 4: Synthesize compound LPc-003x1-d: tert-butyl 3-(2-(2-(methylamino)ethoxy)ethoxy)propanoate.

[0794] At room temperature, methylamine hydrochloride (CAS RN: 593-51-1; 1.48 g, 22.09 mmol) and sodium cyanoborohydride (CAS RN: 25895-60-7; 5.14 g, 81.80 mmol) were added sequentially to a methanol (CAS RN: 67-56-1; 50 ml) solution containing compound LPc-003x1-c (3.8 g, 16.36 mmol). After stirring the reaction mixture at room temperature for 1 hour, dichloromethane (CAS RN: 75-09-2; 50 ml) and a saturated sodium bicarbonate solution (50 ml) were added. After separating the organic phase, the aqueous phase was extracted twice (10 ml × 2) with dichloromethane (CAS RN: 75-09-2). After merging the organic phases, the organic phases were dried with anhydrous sodium sulfate. The colorless oil obtained after evaporating the solvent under reduced pressure was the compound LPc-003x1-d (4.0 g, 16.17 mmol, reaction yield 98.85%).

[0795] LC-MS (m / z, C12H25NO4)=248.2[M+H]+.

[0796] Step 5: Synthesize compound LPc-003x1-e: tert-butyl 1-(9H-fluoren-9-yl)-4-methyl-3-oxo-2,7,10-trioxa-4-azatridecan-13-oate

[0797] At 0°C, N,N-diisopropylethylamine (CAS RN: 75-09-2; 50 ml) and fluorenyl chloroformate (CAS RN: 7087-68-5; 10.59 g, 81.90 mmol) were added sequentially to a solution of compound LPc-003x1-d (4.05 g, 16.38 mmol) dissolved in dichloromethane (CAS RN: 28920-43-6; 8.48 g, 32.76 mmol). The reaction mixture was stirred at 0°C for 1 hour, after which water (10 ml) and dilute hydrochloric acid (1 M, 50 ml) were added. After separating the aqueous and organic phases, the aqueous phase was extracted with dichloromethane (CAS RN: 75-09-2) (10 ml × 3). The combined organic phases were washed with saturated sodium bicarbonate aqueous solution (20 ml) and saturated brine (20 ml). Finally, the organic phase was dried with anhydrous sodium sulfate, and the yellow oil obtained after evaporating dichloromethane solvent under reduced pressure was the compound LPc-003x1-e (7.0 g, 14.90 mmol, reaction yield 91.0%).

[0798] LC-MS(m / z,C27H35NO6)=492.2[(M+Na)] + .

[0799] Step 6: Synthesize compound LPc-003x1-f: 1-(9H-fluoren-9-yl)-4-methyl-3-oxo-2,7,10-trioxa-4-azatridecan-13-oic acid

[0800] At room temperature, trifluoroacetic acid (CAS RN: 76-05-1; 20 ml) was added to a solution of compound LPc-003x1-e (10 g, 21.30 mmol) in dichloromethane (CAS RN: 75-09-2; 80 ml), and the mixture was stirred for 1 hour at room temperature. The reaction solution was concentrated and separated by normal-phase column chromatography (petroleum ether: ethyl acetate = 0:1 to 100:0). The resulting yellow oil was compound LPc-003x1-f (2.97 g, 7.18 mmol, reaction yield 33.73%).

[0801] LC-MS(m / z,C23H27NO6)=414.2[(M+H)] + .

[0802] 1 H NMR(400MHz,DMSO-d6)δ7.75(m,2H),7.59(m,2H),7.33(m,2H),7.26(m,2H),4.50(m,1H),4.40(m,1H),4.25- 4.23(m,1H),3.76-3.73(m,2H),3.61-3.56(m,4H),3.47(m,2H),3.31-3.26(m,2H),2.97(m,3H),2.61(s,2H).

[0803] Step 7: Synthesize compound LPc-003x1-g:(1-(9H-fluoren-9-yl)-4-methyl-3-oxo-2,7,10-trioxa-4-azatridecan-13-oyl)glycylglycyl-L-phenylalanine,(1-(9H-fluoren-9-yl)-4-methyl-3-oxo-2,7,10-trioxa-4-azatridecan-13-oyl)glycylglycyl-L-phenylalanine

[0804] At 0°C, N,N-diisopropylethylamine (CAS RN: 7087-68-5; 1.45 g, 0.25 mmol) and N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN: 148893-10-1; 2.85 g, 7.50 mmol) were added to a solution of N,N-dimethylformamide (CAS RN: 68-12-2; 35 ml) containing compound LPc-003x1-f (3.1 g, 7.5 mmol) at 0°C. After stirring at room temperature for half an hour, glycylglycyl-L-phenylalanine (CAS RN: 6234-26-0; 2.51 g, 9.00 mmol) was added and stirred for 1 hour. The reaction solution was purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) without any treatment, and the resulting yellow solid was the compound LPc-003x1-g (4.5g, 6.67mmol, reaction yield 88.95%).

[0805] LC-MS(m / z,C36H42N4O9)=675.0[M+H] + .

[0806] Step 8: Synthesize compound LPc-003x1-h:(S)-2-(11,14-dioxo-5,8-dioxa-2,12,15-triazaheptadecane-17-amino)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)-3-phenylpropionamide,(S)-2-(11,14-dioxo-5,8-dioxa-2,12, 15-triazaheptadecan-17-amido)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-diox o-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)-3-phenylpropanamide

[0807] At 0°C, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (CAS RN: 25952-53-8; 37.51 mg, 0.19 mmol) and 1-hydroxybenzotriazole (CAS RN: 2592-95-2; 26.44 mg, 0.19 mmol), along with compound LPc-003x1-b (50.0 mg, 0.10 mmol), were added to N,N-dimethylformamide (CAS RN: 68-12-2; 2 ml) containing compound LPc-003x1-g (65.94 mg, 0.10 mmol). After the reaction mixture was heated to room temperature and stirred for 1 hour, diethylamine (CAS RN: 109-89-7; 0.1 ml, 0.96 mmol) was added. After a small-scale test with the reaction solution stirred at room temperature, the solution was purified by reversed-phase chromatography using a C18 column (acetonitrile / water (trifluoroacetic acid) system) to obtain a yellow solid, which was the compound LPc-003x1-h (50.0 mg, 0.05 mmol, reaction yield 52.8%).

[0808] LC-MS(m / z,C46H56FN9O12)=946.6[(M+H)] + .

[0809] Step 9: Synthesis of linker toxin LPc-003x1:(S)-2-(1-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3-methyl-12,15-dioxo-6,9-dioxa-3,13,16-triazaoctadecane-18-amido)-N-(2-(((S)4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-2-oxoethyl)-3-phenylpropionamide,(S)-2-(1-(2,5-dioxo-2,5-dihydro-1H-pyrrol) -1-yl)-3-methyl-12,15-dioxo-6,9-dioxa-3,13,16-triazaoctadecan-18-amido)-N-(2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)am ino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)-3-phenylpropanamide

[0810] At 0°C, Dysmart oxidant (CAS RN: 87413-09-0; 30.6 mg, 0.16 mmol) was added to dichloromethane (CAS RN: 75-09-2; 1 ml) containing N-(2-hydroxyethyl)maleimide (CAS RN: 1585-90-6, 22.5 mg, 0.16 mmol). The reaction mixture was brought to room temperature and stirred for half an hour. Then, N,N-dimethylformamide (CAS RN: 68-12-2; 2 ml) containing compound LPc-003x1-h (50 mg, 0.05 mmol) and triacetoxyborohydride (CAS RN: 56553-60-7; 10.60 mg, 0.05 mmol) were added sequentially. The reaction mixture was then brought to room temperature and stirred for another 30 minutes. The reaction solution was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which is compound LPc-003x1 (3mg, 0.0028mmol, yield after preparative purification: 5.6%).

[0811] LC-MS(m / z,C52H61FN10O14)=1069.6[(M+H)] + .

[0812] Example 2.5 Synthesis of LPc-003x2:MTA-PEG2-GGVA-Toxin T3a,

[0813] Step 1: Synthesize compound LPc-003x2-a:((S)-1-(((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-1-oxopropane-2-yl)amino)-3-methyl-1-oxobutane-2-yl)carbamate, tert-butyl((S)-1-(((S)-1-(((S)-4)-4)-4-(((S)-4)-1 ... -ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3' ,4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate

[0814] At 0°C, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (CAS RN: 25952-53-8; 151.85 mg, 0.79 mmol) and N-hydroxy-7-azabenzotriazole (CAS RN: 39968-33-7; 106.65 mg, 0.79 mmol) were added sequentially to a mixed solution containing (tert-butoxycarbonyl)-L-valine-L-alanine (CAS RN: 70396-18-8; 76.14 mg, 0.26 mmol) and N,N-dimethylformamide (CAS RN: 68-12-2; 6.7 mL). After the addition was complete, the reaction mixture was brought to room temperature and the reaction was stirred for 20 minutes. Then, toxin T3a (120 mg, 0.26 mmol) and copper dichloride (CAS RN: 7447-39-4; 142.01 mg, 1.06 mmol) were added sequentially to the reaction solution. After the reaction solution was reacted at room temperature for 16 hours, the residue obtained after evaporating the solvent under reduced pressure was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-003x2-a (68 mg, 0.09 mmol, reaction yield 35.53%).

[0815] LC-MS(m / z,C36H45FN6O9)=725.4[(M+H)] + .

[0816] 1 H-NMR (400MHz, DMSO-d6) δ10.19(s,1H),9.15(d,J=8.0Hz,1H),8.24(d,J=8.0Hz,1H),8 .03(d,J=12.0Hz,1H),7.32(s,1H),6.74(d,J=12Hz,1H),6.52(s,1H),5.43(s,2H),5.34 (s,2H),4.17(t,J=6.0Hz,1H),4.30(s,2H),3.86(t,J=8.0Hz,1H),3.20(s,3H),2.69(s, 3H),1.99-1.95(m,1H),1.91-1.81(m,2H),1.38(s,9H),1.30(s,3H),0.88-0.81(m,9H).

[0817] Step 2: Synthesize compound LPc-003x2-b:(S)-2-amino-N-((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-1-oxopropane-2-yl)-3-methylbutyramide, (S)-2-amino-N-((S)-1-(((S)- 4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)-3-methylbutanamide

[0818] At 0°C, trifluoroacetic acid (CAS.RN:76-05-1; 1 ml) was added to a solution of compound LPc-003x2-a (68 mg, 0.09 mmol) in dichloromethane (CAS RN: 75-09-2; 3 ml). The reaction mixture was brought to room temperature and stirred for 3 hours. The yellow solid obtained by evaporating the solvent under reduced pressure was compound LPc-003x2-b (54 mg, 0.086 mmol, reaction yield 92.15%).

[0819] LC-MS(m / z,C31H37FN6O7)=625.4[(M+H)] + .

[0820] Step 3: Synthesize compound LPc-003x2-c: glycylglycine

[0821] At 0°C, trifluoroacetic acid (CAS.RN:76-05-1; 1 ml) was added to a solution of dichloromethane (CAS.RN:75-09-2; 3 ml) containing (tert-butoxycarbonyl)-glycylglycine (CAS RN:31972-52-8; 232 mg, 1.00 mmol). The reaction solution was heated to 30°C and stirred for 2 hours. The yellow, transparent oil obtained after evaporating the solvent under reduced pressure was the compound LPc-003x2-c (glycylglycine, 80 mg, 0.58 mmol, reaction yield 58.19%).

[0822] 1 HNMR (400MHz, DMSO-d6) δ11.87(s,1H),8.69(m,1H),8.06(s,2H),3.87(m,2H),3.62(m,2H).

[0823] Step 4: Synthesize compound LPc-003x2-d:(1-(9H-fluoren-9-yl)-4-methyl-3-oxo-2,7,10-trioxa-4-azatridecan-13-oyl)glycylglycine

[0824] At 0°C, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (CAS RN: 25952-53-8; 421.91 mg, 2.20 mmol) and 1-hydroxybenzotriazole (CAS RN: 2592-95-2; 297.41 mg, 2.20 mmol) were added to a solution of N,N-dimethylformamide (CAS RN: 68-12-2; 4 ml) containing compound LPc-003x1-f (455 mg, 1.10 mmol), and the mixture was stirred for 1 hour. Then, compound LPc-003x2-c (159.93 mg, 1.21 mmol) was added. The reaction mixture was then heated to 30°C and stirred for another 3 hours. The yellow oily substance obtained by purifying the reaction solution directly using preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) without any treatment is the compound LPc-003x2-d (525mg, 1.00mmol, reaction yield 90.43%).

[0825] LC-MS(m / z,C27H33N3O8)=528.2[(M+H)] + .

[0826] Step 5: Synthesize compound LPc-003x2-e:(9H-fluoren-9-yl)methyl((2S,5S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-5-isopropyl-2-methyl-1,4,7,10,13-pentoxo-16,19-dioxa-3,6,9,12-tetraazaheptan-21-yl)(methyl)carbamate, (9H-fluoren-9-yl)methyl((2S,5S)-1-(((S)-4)-4 -ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2- b]quinolin-9-yl)amino)-5-isopropyl-2-methyl-1,4,7,10,13-pentaoxo-16,19-dioxa-3,6,9,12-tetraazahenicosan-21-yl)(methyl)carbamate

[0827] At 0°C, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (CAS RN 25952-53-8; 35.60 mg, 0.19 mmol), 1-hydroxybenzotriazole (CAS RN: 2592-95-2; 25.09 mg, 0.19 mmol), and compound LPc-003x2-b (54 mg, 0.086 mmol) were added sequentially to N,N-dimethylformamide (CAS RN: 68-12-2; 4 ml) containing compound LPc-003x2-d (48.98 mg, 0.09 mmol). After the reaction solution was brought to room temperature and stirred for another 3 hours, the reaction solution was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN). The resulting yellow solid was compound LPc-003x2-e (66mg, 0.05mmol, reaction yield 58.13%).

[0828] LC-MS(m / z,C58H68FN9O14)=1134.6[(M+H)] + .

[0829] Step 6: Synthesize compound LPc-003x2-f:(S)-2-(11,14-dioxo-5,8-dioxa-2,12,15-triazaheptadecane-17-amido)-N-((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)1-oxopropane-2-yl)-3-methylbutyramide, (S)-2-(11,14-dioxo-5,8-dioxa-2,12, 15-triazaheptadecan-17-amido)-N-((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo -3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)-3-methylbutanamide

[0830] At 0°C, diethylamine (CAS RN: 109-89-7; 0.01 ml, 0.12 mmol) was added to N,N-dimethylformamide (CAS RN: 68-12-2, 2 ml) containing dissolved compound LPc-003x2-e (66 mg, 0.05 mmol). After stirring the reaction solution at 0°C for 2 hours, the mixture was purified directly by reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-003x2-f (40 mg, 0.04 mmol, reaction yield 75.37%).

[0831] LC-MS(m / z,C43H58FN9O12)=913.0[(M+H)] + .

[0832] Step 7: Synthesize compound LPc-003x2:(S)-2-(1-(2,5-dioxo-2,5-dihydro-1H-pyrrolo-1-yl)-3-methyl-12,15-dioxo-6,9-dioxa-3,13,16-triazaoctadecane-18-amido)-N-((S)-1-(((S)4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino) (S)-2-(1-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3-methyl- 12,15-dioxo-6,9-dioxa-3,13,16-triazaoctadecan-18-amido)-N-((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxy(methyl)amino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)-3-methylbutanamide was dissolved in N-(2-hydroxyethyl)maleimide (CAS) at 0 degrees Celsius. Add Dysmart oxidant (CAS RN: 87413-09-0; 30.6 mg, 0.16 mmol) to a solution of dichloromethane (CAS RN: 75-09-2; 1 mL) containing RN: 1585-90-6 (22.5 mg, 0.16 mmol). After the reaction solution is brought to room temperature, stir for half an hour. Filter the reaction solution and add the filtrate sequentially to a solution of tetrahydrofuran (CAS RN: 109-99-9; 1 mL) containing LPc-003x2-f (30 mg, 0.03 mmol) and sodium triacetylborohydride (CAS RN: 56553-60-7; 10.60 mg, 0.05 mmol). After the reaction solution is brought to room temperature and stirred for 30 minutes, add N,N-dimethylformamide (CAS RN: 68-12-2; 1 mL). The compound LPc-003x2 (1.91 mg, 0.002 mmol, yield 5.6% after preparative purification) was purified by high performance preparative liquid chromatography (column: Welch-Ultimate-C18-10 μm-21.2×150 m, mobile phase: A: 0.1% TFA / H2O, B: ACN).

[0833] LC-MS(m / z,C49H63FN10O14)=1036.0[(M+H)] + .

[0834] Example 2.6 Synthesis of LPc-004x1:MTA-PEG8-VA-Toxin T2a;

[0835] Step 1: Synthesize compound LPc-004x1-a:((S)-1-(((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-1--1-oxopropane-2-yl)amino)-3-methyl-1-oxobutane-2-yl)carbamate, tert-butyl((S)-1-(((S)-1-((( S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4 ':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate

[0836] In a solution of N,N-dimethylformamide (CAS RN: 68-12-2, 4 mL) containing (tert-butoxycarbonyl)-L-valine-L-alanine (CAS RN: 70396-18-8; 246.63 mg, 0.86 mmol), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (CAS RN: 25952-53-8; 327.94 mg, 1.71 mmol), N-hydroxy-7-azabenzotriazole (CAS RN: 39968-33-7; 232.84 mg, 1.71 mmol) was added sequentially to the solution at 0°C and stirred at room temperature for 10 minutes. Then, compound T2a (250.0 mg, 0.57 mmol) and copper chloride (CAS RN: 1344-67-8, 306.67 mg, 2.28 mmol) were added. After stirring the reaction solution at room temperature for 18 hours, the reaction solution was directly purified by reversed-phase column chromatography (C18 column, acetonitrile / water (formic acid) system) to obtain a yellow solid, which is compound LPc-004x1-a (80 mg, 0.11 mmol, reaction yield 19.3%).

[0837] LC-MS(m / z,C35H41FN6O9)=709.7[M+H] + .

[0838] 1 H NMR(400MHz,DMSO-d6)δ10.27(s,1H),9.30(d,J=8.9Hz,1H),9.00(s,1H),8.2 6(d,J=7.0Hz,1H),8.11(d,J=11.9Hz,1H),7.33(s,1H),6.77(m,1H),6.56(s,1 H),5.44(s,2H),5.36(s,2H),4.70(s,1H),4.16(s,3H),3.86(m,1H),2.10-1. 92(m,1H),1.90–1.85(m,2H),1.39(s,9H),1.24(m,3H),0.88(t,J=7.1Hz,9H).

[0839] Step 2: Synthesize compound LPc-004x1-b:(S)-2-amino-N-((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4',6,7]indolizino[1,2-b]quinoline-9-yl)amino)-1-oxopropane-2-yl)-3-methylbutyramide,(S)-2-amino-N-((S)-1-((( S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)-3-methylbutanamide

[0840] At room temperature, trifluoroacetic acid (CAS RN: 75-09-2; 5 mL) was added dropwise to a solution of compound LPc-004x1-a (80 mg, 0.11 mmol) in dichloromethane (CAS RN: 76-05-1, TFA, 2 mL, 26.14 mmol) with stirring. After the addition of trifluoroacetic acid was complete, the reaction mixture was stirred at room temperature for 1 hour. The crude trifluoroacetate obtained after evaporating the solvent under reduced pressure was purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-004x1-b (50 mg, 0.08 mmol, reaction yield 72.78%).

[0841] LC-MS(m / z,C30H33FN6O7)=609.4[M+H] + .

[0842] Step 3: Synthesize compound LPc-004x1-c:(9H-fluoren-9-yl)methyl((29S,32S)-33-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)-29-isopropyl-32-methyl-27,30,33-trioxo-3,6,9,12,15,18,21,24-3,6,9,12,15,18,21,24-octaoxa-28,31-diazatrialkyl)carbamate,(9H-fluoren-9-yl)methyl((2 9S,32S)-33-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizin o[1,2-b]quinoline-9-yl)amino)-29-isopropyl-32-methyl-27,30,33-trioxo-3,6,9,12,15,18,21,24-octaoxa-28,31-diazatritriacontyl)carbamate

[0843] At 0°C, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (CAS RN: 25952-53-8; ... RN:2592-95-2; 22.20 mg, 0.16 mmol), followed by the addition of compound LPc-004x1-b:((S)-2-amino-N-((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4',6,7]indolizino[1,2-b]quinoline-9-yl)amino)-1-oxopropane-2-yl)-3-methylbutyramide, 50.0 mg, 0.08 mmol). The reaction mixture was brought to room temperature and stirred for 1 hour. The reaction solution was purified by preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10μm-19×250mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-004x1-c (50.0 mg, 0.04 mmol, reaction yield 48.52%).

[0844] LC-MS(m / z,C64H80FN7O18)=1254.8[M+H] + .

[0845] Step 4: Synthesize compound LPc-004x1-d:1-amino-N-((S)-1-(((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-9-yl)amino)1-oxopropane-2-yl)amino)-3-methyl-1-oxobutane-2-yl)-3,6,9,12,15,18,21,24-octaoxaheptadecane-27-amide, 1-amino-N-((S)-1-(((S)-1-(((S)-4)-4 -ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2- b]quinolin-9-yl)amino)-1-oxopropan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)-3,6,9,12,15,18,21,24-octaoxaheptacosan-27-amide

[0846] At 0°C, diethylamine (CAS RN: 109-89-7; 0.1 mL) was added to N,N-dimethylformamide (CAS RN: 68-12-2, 3 mL) containing dissolved compound LPc-004x1-c (50 mg, 0.04 mmol). The reaction mixture was brought to room temperature and stirred for half an hour. The reaction mixture was then directly passed through a preparative reversed-phase column chromatography (reversed-phase column: Waters-SunFire-C18-10 μm-19×250 mm, mobile phase: A: 0.1% FA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-004x1-d (30 mg, 0.03 mmol, reaction yield 72.92%).

[0847] LC-MS(m / z,C49H70FN7O16)=1032.6[M+H] + .

[0848] Step 5: Synthesize compound LPc-004x1-e: tert-butyl 3-((2-((tert-butyloxycarbonyl)amino)ethyl)(methyl)amino)propanoate

[0849] tert-butyl acrylate (CAS RN: 1663-39-4; 1.45 mL, 9.99 mmol) and tert-butyl (2-(methylamino)ethyl)carbamate (CAS RN: 122734-32-1; 1682 mg, 9.65 mmol) were added to a reaction flask at room temperature and stirred for 18 hours. The reaction residue obtained after vacuum distillation was directly purified by preparative normal chromatography (petroleum ether: ethyl acetate = 16%) to give compound LPc-004x1-e (1986 mg, 6.57 mmol, reaction yield 68.03%).

[0850] LC-MS(m / z,C14H27N2O4)=303.2[M+H] + .

[0851] Chemical step 6: Synthesize compound LPc-004x1-f: tert-butyl 3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)(methyl)amino)propanoate

[0852] Trifluoroacetic acid (CAS.RN: 76-05-1, 3 ml) was added to a solution of compound LPc-004x1-e (2.0 g, 6.61 mmol) in dichloromethane (CAS RN: 75-09-2; 10 ml) at room temperature and stirred. After stirring at room temperature for three hours, the evaporated solvent and excess trifluoroacetic acid were examined. The resulting residue was dissolved in dichloromethane (CAS RN: 75-09-2; 10 ml), and a saturated sodium bicarbonate solution was added dropwise to the reaction solution at room temperature until the solution became weakly alkaline. Finally, methyl 2,5-dioxo-2,5-dihydro-1H-pyrrole-1-carboxylic acid (CAS RN: 55750-48-61.53 g, 9.87 mmol) was added. After stirring at room temperature for one hour, dichloromethane was added to extract the reaction product from the reaction solution. After merging the dried organic phases, the oily substance obtained by evaporating the solvent under reduced pressure is the compound LPc-004x1-f (600 mg, 2.13 mmol, reaction yield 32%).

[0853] LC-MS(m / z,C14H22N2O4)=283.2[M+1] + .

[0854] 1H NMR (400MHz, CDCl3) δ6.69 (s, 2H), 3.62 (t, J = 6.4Hz, 2H), 2.68 (t, J = 7.2Hz, 2H), 2.56 (t, J = 6.4Hz, 2H), 2.31 (t, J = 7.2Hz, 2H), 2.28 (s, 3H), 1.43 (s, 9H).

[0855] Chemical step 7: Synthesize compound LPc-004x1-g: 3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)(methyl)amino)propanoic acid, 3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)(methyl)amino)propanoic acid

[0856] At room temperature, trifluoroacetic acid (CAS RN: 75-09-2; 2 ml) was added to a solution of dichloromethane (CAS RN: 100 mg, 0.35 mmol) containing compound LPc-004x1-f (100 mg, 0.35 mmol). After stirring at room temperature for 1 hour, the oily substance obtained by evaporating the solvent under reduced pressure was compound LPc-004x1-g (70 mg, 0.31 mmol, reaction yield 89%).

[0857] LC-MS(m / z,C10H14N2O4)=227.2[M+H] + .

[0858] 1 H NMR (400MHz, CDCl3) δ6.67 (s, 2H), 3.86 (t, J = 5.8Hz, 2H), 3.42 (m, 2H), 3.32 (m, 2H) 2.89 (s, 3H), 2.84 (m, 2H).

[0859] Chemical step 8: Synthesis of compound LPc004-x1(MTA-PEG4-VA-Toxin T2c):1-(3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrolo-1-yl)ethyl)(methyl)amino)propionamidyl)-N-((S)-1-(((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6 [7]Indolizidine[1,2-b]quinoline-9-yl)amino)-1-oxopropane-2-yl)amino)-3-methyl-1-oxobutane-2-yl)-3,6,9,12,15,18,21,24-octaoxaheptadecane-27-amide, 1-(3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl )(methyl)amino)propanamido)-N-((S)-1-(((S)-1-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano [3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-1-oxopropan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)-3,6,9,12,15,18,21,24-octaoxaheptacosan-27-amide

[0860] At 0°C, N,N-dimethylformamide (CAS RN: 68-12-2, 1 mL) containing dissolved compounds LPc-004x1-d (30 mg, 0.03 mmol) and LPc-004x1-g (13.15 mg, 0.06 mmol) was added sequentially with N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (HATU; CAS RN: 148893-10-1; 16.58 mg, 0.04 mmol) and N,N-diisopropylethylamine (CAS RN: 7087-68-5, 7.51 mg, 0.06 mmol). After the reaction solution was heated to room temperature and stirred for 30 minutes, it was purified by high performance preparative liquid chromatography and lyophilized (column: Welch-Ultimate-C18-10μm-21.2×150m, mobile phase: A: 0.1% TFA / H2O, B: ACN) to obtain a yellow solid compound LPc-004x1 (10 mg, 0.008 mmol, preparative purification yield 27.74%).

[0861] LC-MS(m / z,C59H82FN9O19)=1240.6[M+H] + .

[0862] The lyophilized solid product LPc-004x1 showed interconvertible oxime cis-trans isomer peaks on RP-HPLC (mobile phase: A: 0.01% FA / H2O B: ACN), with Z configuration: E configuration = 14.83%: 85.17%.

[0863] Example 2.7 Synthesis of LPc-004x2:MTA-PEG8-VKG-ToxinT2a;

[0864] Step 1: Synthesize compound LPc-004x2-a:(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate, tert-butyl(S)-(2-((4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)carbamate

[0865] At room temperature, N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN: 148893-10-1; 4338.53 mg, 11.41 mmol), N,N-diisopropylethylamine (CAS RN: 7087-68-5; 1474.74 mg, 11.41 mmol), and compound T2a (1000 mg, 2.28 mmol) were added sequentially to a solution of N,N-dimethylformamide (CAS RN: 68-12-2; 10 ml) containing (tert-butyloxycarbonyl)glycine (CAS RN: 4530-20-5; 1998.03 mg, 11.41 mmol) dissolved in it. The reaction mixture was stirred at room temperature for 16 hours. The reaction solution was purified directly by high-performance preparative reversed-phase column chromatography (reversed-phase column: Welch-Ultimate-C18-10μm-21.2×150m, mobile phase: A: 0.1% TFA / H2O, B: ACN) without any treatment. After lyophilization, the yellow solid obtained was compound LPc-004x2-a (800mg, 1.34mmol, reaction yield 58.77%).

[0866] LC-MS(m / z,C29H30FN5O8)=596.2[(M+1)] + .

[0867] 1 HNMR (400MHz, DMSO-d6) δ10.17(s,1H),9.27(d,J=8.4Hz,1H),8.96(s,1H),8.06(d,J=11.9Hz,1H),7.31(s,1H),7.19(t,J=5.9Hz, 1H),6.52(s,1H),5.43(s,2H),5.29(s,2H),4.15(s,3H),4.00–3.86(m,2H),1.91-1.84(m,2H),1.42(s,9H),0.89(t,J=7.3Hz,3H).

[0868] Step 2: Compound LPc-004x2-b: (S)-2-amino-N-(4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinolin-9-yl)acetamide, (S)-2-amino-N-(4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinolin-9-yl)acetamide

[0869] At room temperature, trifluoroacetic acid (CAS RN: 76-05-1; 0.3 mL) was added to dichloromethane (CAS RN: 75-09-2; 1 mL) containing compound LPc-004x2-a (100 mg, 0.168 mmol). After stirring for 0.5 hours, excess organic solvent and trifluoroacetic acid were evaporated under reduced pressure to obtain crude trifluoroacetic acid. This crude product was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Welch-Ultimate-C18-10 μm-21.2 × 150 m, mobile phase: A: 0.1% TFA / H2O, B: ACN) to obtain a yellow solid, which was the target compound LPc-004x2-b (50 mg, 0.10 mmol, reaction yield 59.52%).

[0870] LC-MS(m / z,C24H22FN5O6)=496.2[M+1] + .

[0871] 1 HNMR(400MHz, DMSO-d6+5%D2O)δ9.41(d,J=8.3Hz,1H),8.96(s,1H),8.18(s,1H),8.11(d,J=8.0Hz,1H),7.33(s, 1H), 5.44 (s, 2H), 5.35 (s, 2H), 4.17 (s, 3H), 3.62 (d, J = 3.5Hz, 2H), 1.87 (p, J = 6.8Hz, 2H), 0.88 (t, J = 7.3Hz, 3H).

[0872] Step 3: Synthesize compound Fmoc-Val-Lys(N-Boc)-OH:N 2 -((((9H-fluorene-9-yl)methoxy)carbonyl)-L-valineyl)-N 6-tert-Butyloxycarbonyl-L-lysine, N 2 -((((9H-fluoren-9-yl)methoxy)carbonyl)-L-valyl)-N 6 -(tert-butoxycarbonyl)-L-lysine

[0873] At 0°C, N,N-dimethylformamide (CAS RN: 68-12-2; 10.0 mL) containing fluorenylmethoxycarbonyl-L-valine (CAS RN: 68858-20-8; 1000 mg, 2.95 mmol) was added sequentially to N,N-diisopropylethylamine (CAS RN: 7087-68-5, 381.26 mg, 2.95 mmol) and N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN: 148893-10-1; 1121.71 mg, 2.95 mmol) and stirred for 10 minutes. Then, (2S)-2-amino-6-(tert-butoxycarbonylamino)hexanoic acid (CAS RN: 2418-95-3; 726.59 mg, 2.95 mmol) was added at 0°C. The reaction mixture was stirred at 0°C for 5 hours. After evaporating excess solvent under reduced pressure at room temperature, the reaction residue was obtained. This residue was purified by preparative reversed-phase column chromatography (reversed-phase column: Welch-Ultimate-C18-10 μm-21.2 × 150 m, mobile phase: A: 0.1% TFA / H2O, B: ACN). The resulting white solid was the compound Fmoc-Val-Lys(N-Boc)-OH (500 mg, 0.88 mmol, reaction yield 29.83%).

[0874] LC-MS(m / z,C31H41N3O7)=468.2[M-100+H] + .

[0875] 1HNMR(400MHz,DMSO-d6)δ12.54(bs,1H),7.99(s,1H),7.89(d,J=7.5Hz,2H),7.74(t ,J=7.4Hz,2H),7.41(m,3H),7.32(t,J=7.6Hz,2H),6.72(s,1H),4.30-4.19(m,3H),4 .12-4.05(m,1H),3.89(t,J=8.0Hz,1H),2.89-2.81(m,2H),2.07–1.91(m,1H),1.74 -1.48(m,2H),1.36-1.34(m,2H),1.34(s,9H),1.30-1.20(m,2H),0.92-0.80(m,6H).

[0876] Step 4: Synthesize compound LPc-004x2-c:N 2 -((1-(9H-fluorene-9-yl)-3-oxo-2,7,10,13,16,19,22,25,28-nonoxy-4-azatrione-31-oleoyl)-L-valine)-N 6 -tert-Butyloxycarbonyl-L-lysine, N 2 -((1-(9H-fluoren-9-yl)-3-oxo-2,7,10,13,16,19,22,25,28-nonaoxa-4-azahentriacontan-31-oyl)-L-valyl)-N 6 -(tert-butoxycarbonyl)-L-lysine

[0877] At room temperature, 1,8-diazabicyclo[5.4.0]undec-7-ene (CAS RN: 6674-22-2; 27.4 mg, 0.18 mmol) was added to a solution of N,N-dimethylformamide (CAS RN: 68-12-2; 1 ml) containing compound Fmoc-Val-Lys(N-Boc)-OH (100 mg, 0.18 mmol) and stirred at room temperature for three hours. In another reaction flask, N-fluorenylmethoxycarbonyl-octaethylene glycol-propionic acid (CAS RN: 756526-02-0; 92.93 mg, 0.14 mmol) was dissolved in N,N-dimethylformamide (CAS RN: 68-12-2; 5 ml) and cooled to 0°C. Then, N,N-diisopropylethylamine (DIEA, CAS RN: 7087-68-5, 18.10 mg, 0.14 mmol) and N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN: 0.14 mmol) were added sequentially. RN: 148893-10-1; 53.23 mg, 0.14 mmol) was added and stirred for 10 minutes to activate the carboxylic acid. Then, an N,N-dimethylformamide solution containing the unprotected N-fluorenemethyloxycarbonyl group of Fmoc-Val-Lys(N-Boc)-OH was added. After stirring for 0.5 hours at 0°C, excess organic solvent was removed by vacuum evaporation to obtain the reaction residue. This residue was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Welch-Ultimate-C18-10μm-21.2×150m, mobile phase: A: 0.1% TFA / H2O B: ACN). The resulting white oily substance was compound LPc-004x2-c (50 mg, 0.05 mmol, reaction yield 35.71%).

[0878] LC-MS (m / z, C50H78N4O16)=891.4[M-100+H]+.

[0879] Step 5: Synthesize compound LPc-004x2-d:((29S,32S)-1-amino-32-((2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinoline-9-yl)amino)-2-oxoethyl)carbamoyl)-29-isopropyl-27,30-dioxo-3,6,9,12,15,18,21,24-octaoxo-28,31-diazahexadecane-36-yl)carbamate, tert-butyl((29S,32S)-1-amino-32-((2-(((S) )-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoli n-9-yl)amino)-2-oxoethyl)carbamoyl)-29-isopropyl-27,30-dioxo-3,6,9,12,15,18,21,24-octaoxa-28,31-diazahexatriacontan-36-yl)carbamate

[0880] At 0°C, N,N,N',N'-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate urea (CAS RN: 148893-10-1; 114.07 mg, 0.30 mmol), N,N-diisopropylethylamine (CAS RN: 7087-68-5; 38.77 mg, 0.30 mmol), and compound LPc-004x2-b (100 mg, 0.20 mmol) were added sequentially to a solution of N,N-dimethylformamide (CAS RN: 68-12-2; 5 ml) containing compound LPc-004x2-c (198.08 mg, 0.20 mmol). The reaction mixture was then stirred for 0.5 hours after the solution was brought to room temperature. After the reaction solution was cooled back to 0°C, diethylamine (CAS RN: 109-89-7; 29.25 mg, 0.40 mmol) was added and the mixture was stirred for 0.5 hours to remove the N-fluorenemethyloxycarbonyl protecting group. The reaction residue was obtained by evaporating the solvent under reduced pressure. This residue was directly purified by reversed-phase column chromatography (reversed-phase column: Welch-Ultimate-C18-10 μm-21.2 × 150 m, mobile phase: A: 0.1% TFA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-004x2-d (60 mg, 0.048 mmol, reaction yield 24.11%).

[0881] LC-MS(m / z,C59H88FN9O19)=1247.8[(M+1)] + .

[0882] Step 6: Synthesize compound LPc-004x2-e:((36S,39S)-1-(2,5-dioxo-2,5-dihydro-1H-pyrrolo-1-yl)-39-((2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3',4':6,7]indolizino[1,2-b [quinoline-9-yl)amino)-2-oxoethyl)carbamoyl)-36-isopropyl-3-methyl-6,34,37-trioxo-10,13,16,19,22,25,28,31-octaoxa-3,7,35,38-tetraazatetrazane-43-yl)carbamate, tert-butyl((36S,39S)-1-(2,5-dioxo-2,5-dihydro-1H] -pyrrol-1-yl)-39-((2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quino lin-9-yl)amino)-2-oxoethyl)carbamoyl)-36-isopropyl-3-methyl-6,34,37-trioxo-10,13,16,19,22,25,28,31-octaoxa-3,7,35,38-tetraazatritetracontan-43-yl)carbamate

[0883] At 0°C, N,N-dimethylformamide (CAS RN: 68-12-2; 2 ml) containing LPc-004x2-d (50 mg, 0.04 mmol) was added sequentially with LPc-004x1-g (9.08 mg, 0.04 mmol), N,N,N',N'-tetramethyl-O-(7-azabenzotriazol-1-yl)hexafluorophosphate (CAS RN: 148893-10-1; 15.21 mg, 0.04 mmol), and N,N-diisopropylethylamine (CAS RN: 7087-68-5; 10.34 mg, 0.08 mmol). After the reaction solution was heated to room temperature and stirred for 30 minutes, the solvent was evaporated under reduced pressure to obtain the reaction residue. The residue was directly purified by preparative reversed-phase column chromatography (reversed-phase column: Welch-Ultimate-C18-10μm-21.2×150m, mobile phase: A: 0.1% TFA / H2O, B: ACN). The resulting yellow solid was the compound LPc-004x2-e (30mg, 0.02mmol, reaction yield 51.41%).

[0884] LC-MS(m / z,C69H100FN11O22)=678.0[M-100 / 2+1] + 728.0[(M+2H) / 2] 2+ &1477.8[M+Na 2+ ] + .

[0885] Step 7: Synthesize the linker toxin LPc-004x2:N-((S)-1-(((S)-6-amino-1-((2-((((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinoline-9-yl)amino)-1-oxohexane-2-yl) (amino)-3-methyl-1-oxobutane-2-yl)-1-(3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrolo-1-yl)ethyl)(methyl)amino)propionamide)-3,6,9,12,15,18,21,24-octaoxaheptadecane-27-amide, N-((S)-1-(((S)-6-amino-1-((2-(((S)-4-ethyl-8-fluoro-4) -hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinolin-9-yl)amino)-2-oxoethyl)amino)-1-oxohexan-2-yl) amino)-3-methyl-1-oxobutan-2-yl)-1-(3-((2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)(methyl)amino)propanamido)-3,6,9,12,15,18,21,24-octaoxaheptacosan-27-amide

[0886] Trifluoroacetic acid (CAS RN: 76-05-1; 1.0 mL) was added to a solution of compound LPc-004x2-e (28.92 mg, 0.02 mmol) dissolved in dichloromethane (CAS RN: 75-09-2; 2 mL) at room temperature. After reacting at room temperature for 0.5 hours, excess solvent and trifluoroacetic acid were evaporated under reduced pressure to obtain crude trifluoroacetate. The crude product was purified by preparative reversed-phase column chromatography (column: Welch-Ultimate-C18-10 μm-21.2 × 150 m, mobile phase: A: 0.1% TFA / H2O, B: ACN) to obtain a yellow solid, which was compound LPc-004x2 (6 mg, 0.004 mmol, yield 21.48% after preparative purification).

[0887] LC-MS(m / z,C64H92FN11O20)=678.0[M / 2+1] +.

[0888] The lyophilized solid product LPc-004x2 showed interconvertible oxime cis-trans isomer peaks on RP-HPLC (mobile phase: A: 0.01% FA / H2O B: ACN), with Z configuration: E configuration = 13.47%: 86.53%.

[0889] Example 2.8 Synthesis of LPc-004x3:MTA-PEG8-EGCG-ToxinT2a;

[0890] Step 1: Synthesis of compound Fmoc-Glu(O-tert-Butyl)-O-Su: 5-tert-butyl-1-(2,5-dioxopyrrolidin-1-yl)(((9H-fluoren-9-yl)methoxy)carbonyl)-L-glutamate, 5-(tert-butyl)1-(2,5-dioxopyrrolidin-1-yl)(((9H-fluoren-9-yl)methoxy)carbonyl)-L-glutamate

[0891] At 0°C, a solution of tetrahydrofuran (CAS RN: 109-99-9; 50 mL) containing fluorenemethoxycarbonyl-L-glutamic acid tert-butyl ester (CAS RN: 71989-18-9; 5 g, 11.75 mmol) and N-hydroxysuccinimide (CAS RN: 6066-82-6; 1.62 g, 14.10 mmol) dissolved in tetrahydrofuran (CAS RN: 109-99-9; 10 mL) was slowly added dropwise to the solution containing N′,N-dicyclohexyldiimide (CAS RN: 538-75-0; 2.91 g, 14.10 mmol) and stirred at 0°C for half an hour. After the reaction solution was brought to room temperature, stirring continued for 3 hours. The insoluble solids in the reaction solution were removed by filtration. The resulting filtrate was evaporated under reduced pressure to reduce the solvent volume, and then slowly added dropwise to petroleum ether to precipitate a solid product. The white solid obtained by filtration was the compound Fmoc-Glu(O-tert-Butyl)-O-Su (5.9 g, 11.39 mmol, reaction yield 96.93%).

[0892] LC-MS(m / z,C28H30N2O8)=545.2[M+Na] + .

[0893] 1H NMR (400MHz, DMSO-d6) δ8.11(d,J=7.9Hz,1H),7.90(d,J=7.5Hz,2H),7.71(t,J=6.7Hz,2H),7.42(t,J=7.4Hz,2H),7.33(t,J=7.4Hz, 2H),4.55–4.50(m,1H),4.35(d,J=6.9Hz,2H),4.25(t,J=6.9Hz,1H),2.81(s,4H),2.47–2.37(m,2H),2.14–1.89(m,2H),1.40(s,9H).

[0894] Step 2: Synthesize compound Fmoc-Glu(O-tert-Butyl)-Gly-OH:(S)-(2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-5-(tert-butoxy)-5-oxopentanoyl)glycine,(S)-(2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-5-(tert-butoxy)-5-oxopentanoyl)glycine

[0895] At 0°C, sodium carbonate (CAS RN: 497-19-8, 2.60 g, 24.5 mmol) and a tetrahydrofuran (CAS RN: 109-99-9, 10 ml) solution containing glycine (CAS RN: 56-40-6; 1.38 g, 18.37 mmol) were added to a mixed solution of water (50 ml) and tetrahydrofuran (CAS RN: 109-99-9, 10 ml) containing Fmoc-Glu(O-tert-Butyl)-O-Su (6.4 g, 12.25 mmol) were added and stirred for half an hour. After the reaction solution was heated to room temperature and stirred overnight, the pH of the reaction solution was adjusted to 2 to 3 using saturated citric acid, and the reaction solution was extracted with ethyl acetate. The obtained organic phase was dried with anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to obtain a white solid, which was the compound Fmoc-Glu(O-tert-Butyl)-Gly-OH (5.8 g, 12.12 mmol, reaction yield 99.49%).

[0896] LC-MS(m / z,C26H30N2O7)=505.2[M+Na]+&426[M-56+H] + .

[0897] 1H NMR (400MHz, DMSO-d6) δ12.55(s,1H),8.19(t,J=5.9Hz,1H),7.89(d,J=7.5H z,2H),7.74(t,J=7.1Hz,2H),7.56(d,J=8.3Hz,1H),7.42(t,J=6.9Hz,2H),7. 33(t,J=6.9Hz,2H),4.32–4.28(m,1H),4.23(t,J=6.6Hz,2H),4.10–4.04(m,1 H),3.86–3.66(m,2H),2.28(t,J=8.0Hz,2H),1.96-1.68(m,2H),1.39(s,9H).

[0898] Step 3: Synthesize compound LPc-004x3-a:(5S,11S)-5-(3-(tert-butoxy)-3-oxopropyl)-1-(9H-fluoren-9-yl)-3,6,9-trioxo-11-(3-ureidopropyl)-2-oxa-4,7,10-triazadodecan-12-oic acid.

[0899] At 0°C, N,N′-dicyclohexylcarbodiimide (CAS RN: 109-99-9, 8 ml) was added to a tetrahydrofuran solution containing Fmoc-Glu(O-tert-Butyl)-Gly-OH (500 mg, 1.04 mmol) and N-hydroxysuccinimide (CAS RN: 6066-82-6, 131.20 mg, 1.14 mmol). After stirring the reaction solution at 0°C for 3 hours, the insoluble solids in the reaction solution were filtered off, and L-citrulline (CAS RN: 372-75-8, 343.1 mg, 1.96 mmol), sodium carbonate (CAS RN: 497-19-8; 276.63 mg, 2.61 mmol), and water (8 mL) were added sequentially to the filtrate at 0°C. After the addition of reactants was complete, the reaction solution was brought to room temperature and stirred for another 16 hours. After evaporating the tetrahydrofuran solvent from the reaction solution under reduced pressure, the pH of the reaction solution was adjusted to 2 to 3 using a saturated citric acid solution. The white solid collected after filtering the reaction solution was compound LPc-004x3-a (490 mg, 0.766 mmol, reaction yield 73.65%).

[0900] LC-MS(m / z,C32H41N5O9)=640.4[M+H] + .

[0901] 1 H NMR (400MHz, DMSO-d6) δ12.55(bs,1H),8.13(t,J=5.8Hz,1H),8.05(d,J=7.8Hz,1H),7.89(d,J=7.5H z,2H),7.73(t,J=7.4Hz,2H),7.58(d,J=7.9Hz,1H),7.42(t,J=7.4Hz,2H),7.37–7.30(m,2H),5.93(t ,J=5.8Hz,1H),5.37(s,2H),4.36–4.14(m,4H),4.04-3.98(m,1H),3.80-3.68(m,2H),2.94(q,J=6.5H z,2H),2.25(t,J=7.9Hz,2H),1.97–1.84(m,1H),1.78–1.67(m,2H),1.59-1.50(m,1H),1.39(s,11H).

[0902] Step 4: Compound LPc-004x3-b: tert-butyl(S)-4-amino-5-((2-(((S)-1-((2-(((S)-4-ethyl-8-fluoro-4-hydroxy-11-((methoxyimino)methyl)-3,14-dioxo-3,4,12,14...

Claims

A ligand-drug conjugate or a pharmaceutically acceptable salt thereof, characterized in that, The ligand-drug conjugate has the structure shown in formula (I): mAb—(L—D)z Equation (I); Where mAb is a ligand that binds to the target site; z is the average conjugation ratio of the drug ligands, and z is selected from an integer or decimal of about 1 to about 16; L is a connection unit with the following structure: —L4—L3—L2—L1—; where, The L4 is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, position 1 is connected to the ligand, and position 2 is connected to L3; R X Selected from C 1-6 Alkyl and C 3-6 cycloalkyl, the C 1-6 Alkyl and C 3-6 The cycloalkyl group is optionally surrounded by one or more radicals selected from halogen, cyano, hydroxyl, C 1-6 Alkyl and C 3-6 Substituents of cycloalkyl groups; The L3 is selected from Where s is an integer from 1 to 30, with 1 bit connected to L4 and 2 bits connected to L2; The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by 1, 2, or 3 carbon atoms. 1-6 Alkyl groups are substituted; The L1 is absent or is a self-destructing unit; D is a drug with the structure shown in formula (II): The wavy line represents the key connecting L and D; R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl groups and C 1-6 Alkoxy; W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups. The ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to claim 1 is characterized in that, In equation (II), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-33 Halogenated alkyl groups and C 1-3 Alkoxy; Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy; More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine. The ligand-drug conjugate or its pharmaceutically acceptable salt according to claim 1 or 2 is characterized in that, In equation (II), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-3 Halogenated alkyl groups and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen; Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 All are hydrogen; More preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 All are hydrogen; More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-3 is characterized in that, In equation (II), R 1 R 2 and R 3 Both are hydrogen. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-3 is characterized in that, In equation (II), R 1 It is fluorine, R 2 and R 3 Both are hydrogen. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of embodiments 1-5 is characterized in that... In equation (II), W is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms; More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl; More preferably, R 4 and R 5 All are methyl; or, More preferably, R 4 and R 5 All are ethyl; or, More preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-5 is characterized in that, In equation (II), W is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3-6 Substituents of cycloalkyl groups; Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic groups; More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms they are attached to, they form a six-membered heterocyclic group containing 2 to 3 heteroatoms; More preferably, R 6 and R 7 All are methyl; or, More preferably, R 6 and R 7 All are ethyl; or, More preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-5 is characterized in that, In equation (II), W is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; More preferably, R 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl and methoxy; More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-8 is characterized in that, The L4 is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, position 1 is connected to the ligand, and position 2 is connected to L3; R X Selected from C 1-3 Alkyl and C 3-5 cycloalkyl, the C 1-3 Alkyl and C 3-5 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, and C. 1-3 Alkyl groups are substituted. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-9 is characterized in that, m1 can be 1, 2, 3, 4 or 5; Preferably, m1 is an integer from 1 to 3; More preferably, m1 is 2. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-10 is characterized in that, m2 can be 0, 1, 2, 3, 4 or 5; Preferably, m2 is an integer between 0 and 3; More preferably, m2 is 0; or More preferably, m2 is 2. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-11 is characterized in that, R X C 1-3 alkyl; Preferably, R X It is methyl or ethyl; More preferably, R X It is a methyl group. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-11 is characterized in that, Preferably, R X C 3-5 cycloalkyl; Preferably, R X It is cyclopropyl. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-13 is characterized in that, The L4 is The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-13 is characterized in that, The L4 is The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-13 is characterized in that, The L4 is The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-16 is characterized in that, The L3 is selected from Where s is an integer from 1 to 24, with 1 bit connected to L4 and 2 bits connected to L2. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-17 is characterized in that, s is an integer from 1 to 20; Preferably, s is an integer from 2 to 12; Preferably, s is an integer from 2 to 8; More preferably, s is 2; or More preferably, s is 4; or More preferably, s is 8. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-18 is characterized in that, The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; Preferably, when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-3 Alkyl groups are substituted; More preferably, when the amino acid residue is Lys, the side chain amino group of Lys is replaced by two methyl groups, two ethyl groups, or two n-propyl groups. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-19 is characterized in that, The L2 is selected from -Lys-, -Ala-Lys-, -Gly-Lys-, -Lys-Gly-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Lys-Val-, -Al a-Ala-Asn-, -Ala-Ala-Asn-, -Ala-Ala-Asp-, -Ala-Lys-Gly-, -(D-Val)-Leu-Lys-, -Glu-Gly-Lys-, -Gly-Lys-Gly-, -Lys-Ala-Asn-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Val-Ala-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, and -Val-Lys-Gly-Gly-; wherein, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; Preferably, the L2 is selected from -Val-Ala-, -Glu-Gly-Lys-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, or -Gly-Gly-Val-Ala-, wherein the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; More preferably, L2 is -Gly-Gly-Phe-Gly-; or, More preferably, L2 is -Glu-Gly-Lys-, wherein the side chain amino group of Lys is replaced by two methyl groups; or More preferably, L2 is -Glu-Gly-Cit-Gly-. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-20 is characterized in that, L1 does not exist. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-20 is characterized in that, L1 is selected from: Of these, bit 1 is connected to L2, and bit 2 is connected to D. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-22 is characterized in that, L is selected from the structures in Table 1. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-23 is characterized in that, The mAb can be an antibody or its antigen-binding fragment; Preferably, the antibody is selected from the group consisting of chimeric antibodies, humanized antibodies, and fully human antibodies. Preferably, the antigen-binding fragment is selected from the group consisting of Fab′, Fab, F(ab′)2, single-domain antibodies (DABs), Fv, and scFv (single-chain Fv). More preferably, the mAb is an antibody or its antigen-binding fragment targeting the following targets: 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, O772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79b, CCL5, CCR 5. CCR7, CD11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD40, CD45, CD 45(PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.

2. c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EG FRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRα, GD2, GEDA, GP C-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra, IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP1 4, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC3 9A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, short proteoglycans, mesothelin, endothelial peptide receptors, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin α4β7, integrin α5β6, trophoblast cell glycoproteins, and tissue factor; More preferably, the mAb is an antibody or its antigen-binding fragment targeting the following targets: HER2, HER3, B7H3, TROP2, Claudin 18.2, CD30, CD33, CD70, EGFR, and FRα; For example, the mAb is an anti-Trop-2 antibody or its antigen-binding fragment; preferably, the mAb is datopotamab, sacituzumab or its antigen-binding fragment. For example, the mAb is an anti-Her 2 antibody or its antigen-binding fragment; preferably, the mAb is anbenitamab, coprelotamab, disitamab, gancotamab, margetuximab, pertuzumab, timigutuzumab, zanidatamab, Trastuzumab, Pertuzumab or its antigen-binding fragment. For example, the mAb is an anti-Her3 antibody or its antigen-binding fragment; preferably, the mAb is a barecetamab, duligotuzumab, elgemtumab, istiratumab, lumretuzumab, patritumab, seribantumab, zenocutuzumab, 202-2-1 antibody or its antigen-binding fragment. For example, the mAb is an anti-EGFR antibody or its antigen-binding fragment; preferably, the mAb is demupitamab, depatuxizumab, futuximab, imgatuzumab, lapatuximab, losatuxizumab, matuzumab, modotuximab, necitumumab, nimotuzumab, panitumumab, pimurutamab, serclutamab, tomuzotuximab, zalutumumab, Cetuximab or its antigen-binding fragment. For example, the mAb is an anti-B7H3 antibody or its antigen-binding fragment; preferably, the mAb is 1D1, 1D1-01, 2E3, 2E3-02 antibody, enoblituzumab, mirzotamab, omburtamab or its antigen-binding fragment. For example, the mAb is an anti-LIV1 antibody or its antigen-binding fragment; preferably, the mAb is Ladiratuzumab or its antigen-binding fragment. For example, the mAb is an anti-FRα antibody or its antigen-binding fragment; preferably, the mAb is v30384 or its antigen-binding fragment. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-24 is characterized in that, The average conjugation ratio z of the drug ligand is an integer or decimal of about 1 to about 10; Preferably, the average conjugation ratio z of the drug ligand is an integer or fraction from about 3 to about 8; or Preferably, the average conjugation ratio z of the drug ligand is an integer or fraction of about 1 to about 2, about 2 to about 3, about 3 to about 4, about 4 to about 5, about 5 to about 6, about 6 to about 7, about 7 to about 8, about 8 to about 9, or about 9 to about 10; or Preferably, the average conjugation ratio z of the drug ligand is about 1, about 2, about 3, about 4, about 5, about 6, about 7 or about 8. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-25 is characterized in that, The ligand-drug conjugate shown in formula (I) is selected from the structures in Table 2. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-26 is characterized in that, The ligand-drug conjugate shown in formula (I) is selected from the structures in Table 3. The ligand-drug conjugate or its pharmaceutically acceptable salt according to any one of claims 1-27 is characterized in that, The ligand-drug conjugate is replaced with an isotope; Preferably, the isotope substitution is deuterium atom substitution. A compound or its tautomers, meso, racemic, enantiomers, diastereomers, or mixtures thereof, or a pharmaceutically acceptable salt thereof, characterized in that, The compound has the structure shown in formula (IA): L-D formula (IA); Wherein, L is a connecting unit with the following structure: L4'—L3—L2—L1—; where, The L4' is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, and 2 bits are connected to L3; R X Selected from C 1-6 Alkyl and C 3-6 cycloalkyl, the C 1-6 Alkyl and C 3-6 The cycloalkyl group is optionally surrounded by one or more radicals selected from halogen, cyano, hydroxyl, C 1-6 Alkyl and C 3-6 Substituents of cycloalkyl groups; G1 and G2 are leaving groups; The L3 is selected from Where s is an integer from 1 to 30, with 1 bit connected to L4 and 2 bits connected to L2; The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by 1, 2, or 3 carbon atoms. 1-6 Alkyl groups are substituted; The L1 is absent or is a self-destructing unit; D is a drug with the structure shown in formula (II): in, The wavy line represents the key connecting L and D; R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl groups and C 1-6 Alkoxy; W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups. The compound according to claim 29, or its tautomers, meso compounds, racemates, enantiomers, diastereomers, or mixtures thereof, or pharmaceutically acceptable salts thereof, is characterized in that, In equation (II), R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-3 Halogenated alkyl groups and C 1-3 Alkoxy; Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy; More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine. The compound according to claim 28 or 29, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, In equation (II), R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-3 Halogenated alkyl and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen; Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 All are hydrogen; More preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 All are hydrogen; More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen. The compound according to any one of claims 29-31, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, In equation (II), R 1 R 2 and R 3 Both are hydrogen. The compound according to any one of claims 29-31, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, In equation (II), R 1 It is fluorine, R 2 and R 3 Both are hydrogen. The compound according to any one of claims 29-33, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, In equation (II), W is Among them, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2- 4-Alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6- 10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic groups; More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 4 and R 5 Together with the N atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms; More preferably, R 4 and R 5 All are methyl; or, More preferably, R 4 and R 5 All are ethyl; or, More preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom. The compound according to any one of claims 29-33, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, In equation (II), W is Among them, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2- 4-Alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1- 3-alkyl and C 3-6 Substituents of cycloalkyl groups; Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic groups; More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms they are attached to, they form a six-membered heterocyclic group containing 2 to 3 heteroatoms; More preferably, R 6 and R 7 All are methyl; or, More preferably, R 6 and R 7 All are ethyl; or, More preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom. The compound according to any one of claims 29-33, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, In equation (II), W is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; More preferably, R 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and wherein R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl and methoxy; More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups. The compound according to any one of claims 29-36, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, G1 and G2 are each independently selected from halogen, sulfonyl, sulfonate, nitro, and optionally substituted with one or more of the following groups: alkyl sulfide, aryl sulfide, heteroaryl sulfide, alkyl sulfoxide, aryl sulfoxide, heteroaryl sulfoxide, alkyl sulfonyl, aryl sulfonyl, heteroaryl sulfonyl, wherein each substituent is independently selected from hydrogen, deuterium, halogen, CN, nitro, C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, C 1-6 Alkyl carbonyl, halogenated C 1-6 Alkyl carbonyl, 5-10 membered heterocyclic carbonyl, 6-10 membered aryl, 5-16 membered heteroaryl, 6-10 membered aryl carbonyl and 5-16 membered heteroaryl carbonyl; Preferably, G1 and G2 are each independently selected from F, Cl, Br, I, OMs (methanesulfonate group), Ots (p-toluenesulfonate group), OTf (trifluoromethanesulfonate group), methanesulfonyl group, ethanesulfonyl group, p-toluenesulfonyl group, naphthalenesulfonyl group, aryl thioether group optionally substituted with one or more substituents, and heteroaryl thioether group optionally substituted with one or more substituents; More preferably, G1 and G2 are each independently selected from F, Cl, Br, OMs, OTs, methanesulfonyl, p-toluenesulfonyl and phenyl thioether groups optionally substituted by one or more substituents; More preferably, G1 and G2 are each independently selected from Cl, methanesulfonyl, and phenyl thioether group optionally substituted with one or more substituents. The compound according to any one of claims 29-37, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, G1 is The compound according to any one of claims 29-38, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The G2 is Cl or methanesulfonyl. The compound according to any one of claims 29-39, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L4' is selected from Where m1 is an integer from 1 to 5, m2 is an integer from 0 to 5, and 2 bits are connected to L3; R X Selected from C 1-3 Alkyl and C 3-5 cycloalkyl, the C 1-3 Alkyl and C 3-5 The cycloalkyl group is optionally surrounded by one or more elements selected from halogen, cyano, hydroxyl, and C. 1-3 Alkyl groups are substituted. The compound according to any one of claims 29-40, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, m1 can be 1, 2, 3, 4 or 5; Preferably, m1 is 1, 2, or 3; More preferably, m1 is 2. The compound according to any one of claims 29-41, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, m2 can be 0, 1, 2, 3, 4 or 5; Preferably, m2 is 0, 1, 2 or 3; More preferably, m2 is 0; or More preferably, m2 is 2. The compound according to any one of claims 29-42, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, R X C 1-3 alkyl; Preferably, R X It is methyl or ethyl; More preferably, R X It is a methyl group. The compound according to any one of claims 29-42, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, R X C 3-5 cycloalkyl; Preferably, R X It is cyclopropyl. The compound according to any one of claims 29-44, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L4' is The compound according to any one of claims 29-44, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L4' is The compound according to any one of claims 29-44, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L4' is The compound according to any one of claims 29-47, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L3 is selected from Where s is an integer from 1 to 24, with 1 bit connected to L4' and 2 bits connected to L2. The compound according to any one of claims 29-48, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, s is an integer from 1 to 20; Preferably, s is an integer from 2 to 12; Preferably, s is an integer from 2 to 8; More preferably, s is 2; or More preferably, s is 4; or More preferably, s is 8. The compound according to any one of claims 29-49, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L2 is an amino acid or a peptide composed of 2-10 amino acids; the amino acid is selected from natural amino acid residues, non-natural amino acid residues, or their stereoisomers; when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; Preferably, when the amino acid residue is Lys, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-3 Alkyl groups are substituted; More preferably, when the amino acid residue is Lys, the side chain amino group of Lys is replaced by two methyl groups, two ethyl groups, or two n-propyl groups. The compound according to any one of claims 29-50, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The L2 is selected from -Lys-, -Ala-Lys-, -Gly-Lys-, -Lys-Gly-, -Val-Cit-, -Val-Ala-, -Val-Lys-, -Lys-Val-, -Al a-Ala-Asn-, -Ala-Ala-Asn-, -Ala-Ala-Asp-, -Ala-Lys-Gly-, -(D-Val)-Leu-Lys-, -Glu-Gly-Lys-, -Gly-Lys-Gly-, -Lys-Ala-Asn-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, -Gly-Gly-Val-Ala-, -Lys-Ala-Ala-Asn-, -Lys-Ala-Ala-Asp-, and -Val-Lys-Gly-Gly-; wherein, the side chain amino group of Lys is optionally surrounded by one or two C atoms. 1-6 Alkyl groups are substituted; Preferably, L2 is selected from -Val-Ala-, -Glu-Gly-Lys-, -Val-Lys-Gly-, -Glu-Gly-Cit-Gly-, -Gly-Gly-Phe-Gly-, or -Gly-Gly-Val-Ala-; More preferably, L2 is -Gly-Gly-Phe-Gly-; or, More preferably, L2 is -Glu-Gly-Lys-, wherein the side chain amino group of Lys is replaced by two methyl groups; or, More preferably, L2 is -Glu-Gly-Cit-Gly-. The compound according to any one of claims 29-51, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, L1 does not exist. The compound according to any one of claims 29-51, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, L1 is selected from: Of these, bit 1 is connected to L2, and bit 2 is connected to D. The compound according to any one of embodiments 29-53, or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that the compound of formula (IA) is selected from the structures in Table 4. The compound according to any one of embodiments 29-54, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that... The compound was substituted with an isotope; Preferably, the isotope substitution is deuterium atom substitution. A compound or its tautomers, meso, racemic, enantiomers, diastereomers, or mixtures thereof, or a pharmaceutically acceptable salt thereof, characterized in that, The compound has the structure shown in formula (IIA): Among them, R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Halogenated alkyl groups and C 1-6 Alkoxy; W selected Among them, R 4 R 5 R 6 R 7 R 8 and R 9 Each is independently selected from hydrogen and C. 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl and C 6-14 Aryl-C 1-6 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 3-8 Heterocyclic group, or R 6 and R 7 Together with the N and O it connects to, it forms C 3-8 Heterocyclic group; the C 1-6 Alkyl, C 1-6 Heteroalkyl, C 2-6 alkenyl, C 2-6 alkynyl group, C 3-8 cycloalkyl, C 6-14 Aryl, C 6-14 Aryl-C 1-6 Alkyl and C 3-8 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy and C 3-6 Substituents of cycloalkyl groups. The compound according to claim 56, or its tautomers, meso compounds, racemates, enantiomers, diastereomers, or mixtures thereof, or pharmaceutically acceptable salts thereof, are characterized in that, R 1 R 2 and R 3 Each is independently selected from hydrogen, halogen, and C. 1-3 Alkyl, C 1-33 Halogenated alkyl and C 1-3 Alkoxy; Preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, and trifluoromethoxy; More preferably, R 1 R 2 and R 3 Each is independently selected from hydrogen, fluorine, chlorine, and bromine. The compound according to claim 56 or 57, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, R 1 Selected from hydrogen, halogens, C 1-3 Alkyl, C 1-33 Halogenated alkyl groups and C 1-3 Alkoxy, R 2 and R 3 All are hydrogen; Preferably, R 1 Selected from hydrogen, halogens and C 1-3 Alkyl, R 2 and R 3 All are hydrogen; More preferably, R 1 Selected from hydrogen, fluorine, chlorine, bromine, methyl, and ethyl, R 2 and R 3 All are hydrogen; More preferably, R 1 Selected from hydrogen or fluorine, R 2 and R 3 Both are hydrogen. The compound according to any one of claims 56-58, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, R 1 R 2 and R 3 Both are hydrogen. The compound according to any one of claims 56-59, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, R 1 It is fluorine, R 2 and R 3 Both are hydrogen. The compound according to any one of claims 56-60, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, W is Its characteristic is that R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; Preferably, R 4 and R 5 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 4 and R 5 Together with the N it is connected to, they form C 5-6 Heterocyclic groups; More preferably, R 4 and R 5 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 4 and R 5 Together with the N atoms it is attached to, it forms a six-membered heterocyclic group containing 2 to 3 heteroatoms; More preferably, R 4 and R 5 All are methyl; or, More preferably, R 4 and R 5 All are ethyl; or, More preferably, R 4 and R 5 Together with the N atom it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom. The compound according to any one of claims 56-60, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, W is Its characteristic is that R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic group; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl and C 3-6 Substituents of cycloalkyl groups; Preferably, R 6 and R 7 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group and C 3-6 cycloalkyl, or R 6 and R 7 Together with the N and O it connects to, it forms C 5-6 Heterocyclic groups; More preferably, R 6 and R 7 Each is independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, and cyclopropyl, or R 6 and R 7 Together with the N and O atoms they are attached to, they form a six-membered heterocyclic group containing 2 to 3 heteroatoms; More preferably, R 6 and R 7 All are methyl; or, More preferably, R 6 and R 7 All are ethyl; or, More preferably, R 6 and R 7 Together with the N and O atoms it is attached to, it forms a six-membered heterocyclic group containing one nitrogen atom and one oxygen atom. The compound according to any one of claims 56-60, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, W is Among them, R 8 and R 9 Each is independently selected from hydrogen and C. 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl; the C 1-3 Alkyl, C 1-3 Heteroalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl, C 6-10 Aryl-C 1-3 Alkyl and C 5-6 The heterocyclic group is optionally surrounded by one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; Preferably, R 8 Selected from hydrogen and C 1-3 Alkyl, R 9 Selected from C 1-3 Alkyl, C 1-3 Haloalkyl, C 2-4 alkenyl, C 2-4 alkynyl group, C 3-6 cycloalkyl, C 6-10 Aryl and C 6-10 Aryl-C 1-3 Alkyl, and the R 9 Optionally, it is selected from one or more groups selected from halogen, cyano, hydroxyl, C 1-3 Alkyl, C 1-3 Alkoxy and C 3-6 Substituents of cycloalkyl groups; More preferably, R 8 Selected from hydrogen and methyl, R 9 Selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, phenyl, or benzyl, and said R 9 Optionally substituted with one or more substituents selected from halogen, cyano, hydroxy, methyl and methoxy; More preferably, R 8 For hydrogen, R 9 All are methyl, ethyl, phenyl, or benzyl, and the R 9 Optionally substituted with one or more substituents selected from halogens, hydroxyl groups, methyl groups, and methoxy groups. The compound according to any one of claims 56-63, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The compounds are selected from the structures in Table 5A. The compound according to any one of claims 56-64, or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, is characterized in that, The compound was substituted with an isotope; Preferably, the isotope substitution is deuterium atom substitution. A method for preparing the ligand-drug conjugate of formula (I) according to any one of claims 1-28, characterized in that, The method includes contacting a ligand mAb with the structure of formula (IA) according to any one of claims 29-55. A pharmaceutical composition, characterized in that, The pharmaceutical composition contains a ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of claims 1-28, or the pharmaceutical composition contains a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, according to any one of embodiments 56-65. Use of a ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of claims 1-28, a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to any one of claims 29-55, a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, according to claims 56-65, or a pharmaceutical composition according to claim 67, in the preparation of a medicament for treating and / or preventing tumors; Preferably, the drug is a ligand-drug conjugate. A method of treating and / or preventing tumors, comprising administering to a subject in need a ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of claims 1-28, a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition according to claim 67. A ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of claims 1-28, a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition according to claim 67, for the treatment and / or prevention of tumors. The use according to claim 68, the method according to claim 69, or the ligand-drug conjugate or its pharmaceutically acceptable salt or pharmaceutical composition according to claim 70, the compound or its tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof, or its pharmaceutically acceptable salt, or the pharmaceutical composition thereof, characterized in that, The tumors were selected from those associated with the expression of the following groups: 5T4, AGS-16, ANGPTL4, ApoE, CTGF, CXCR5, FGF2, MCPT8, MFI2, MS4A7, NCA, Sema5b, SLITRK6, STC2, TGF, 0772P, ACTA2, ADGRE1, AG-7, AIF1, AKR1C1, AKR1C2, ASLG659, Axl, B7H3, BAFF-R, BCMA, BMPR1B, BNIP3, C1QA, C1QB, CA6, CADM1, CCD79b, CCL5, CCR5, CCR7. , CD11c, CD123, CD138, CD142, CD147, CD166, CD19, CD21, CD20, CD205, CD22, CD223, CD228, CD25, CD30, CD33, CD37, CD38, CD40, CD45, CD45 ( PTPRC), CD46, CD47, CD49D(ITGA4), CD56, CD66e, CD70, CD71, CD72, CD74, CD79a, CD79b, CD80, CDCP1, CDH11, CD11b, CEA, CEACAM5, Claudin 18.

2. c-Met, COL6A3, COL7A1, CRIPTO, CSF1R, CTSD, CTSS, CXCL11, CXCL10, DDIT4, DLL3, DLL4, DR5, E16, EFNA4, EGFR, EG FRvIII, EGLN, EGLN3, EMR2, ENPP3, EpCAM, EphA2, EphB2R, ETBR, FcRH2, FcRHl, FGFR2, FGFR3, FLT3, FRα, GD2, GEDA, GP C-1, GPNMB, GPR20, GZMB, HER2, HER3, HLA-DOB, HMOX1, IFI6, IFNG, IGF-1R, IGFBP3, IL10RA1, IL-13R, IL-2, IL20Ra, IL-3, IL-4, IL-6, IRTA2, KISS1R, KRT33A, LIV-1, LOX, LRP-1, LRRC15, LUM, LY64, LY6E, Ly86, LYPD3, MDP, MMP10, MMP1 4, MMP16, MPF, MSG783, MSLN, MUC-1, NaPi2b, Napi3b, Nectin-4, NOG, P2X5, pCAD, P-Cadherin, PDGFRA, PDK1, PD-L1, PFKFB3, PGF, PGK1, PIK3AP1, PIK3CD, PLOD2, PSCA, PSCAhlg, PSMA, PTK7, P-cadherin, RNF43, ROR1, ROR2, SERPINE1, SLC3 9A6, SLTRK6, STAT1, STEAP1, STEAP2, TCF4, TENB2, TGFB1, TGFB2, TGFBR1, TNFRSF21, TNFSF9, Trop-2, TrpM4, Tyro7, UPK1B, VEGFA, WNT5A, epidermal growth factor, short proteoglycans, mesothelin, endothelial peptide receptors, mucins (such as mucin 1 and mucin 16), guanylate cyclase C, integrin α4β7, integrin α5β6, trophoblast cell glycoproteins, and tissue factor; Preferably, the tumor is selected from tumors associated with the expression of the following groups: HER2, HER3, B7H3, TROP2, LIV-1, Claudin 18.2, CD30, CD33, CD70, EGFR, and FRα; For example, the tumor is a tumor associated with HER2 expression; For example, the tumor is a tumor associated with HER3 expression; For example, the tumor is a tumor associated with B7H3 expression; For example, the tumor described is a tumor associated with TROP2 expression; For example, the tumor is a tumor associated with LIV-1 expression; For example, the tumor is one associated with Claudin 18.2 expression; For example, the tumor is a tumor associated with CD30 expression; For example, the tumor is a tumor associated with CD33 expression; For example, the tumor is a tumor associated with CD70 expression; For example, the tumor is a tumor associated with EGFR expression; For example, the tumor is a tumor associated with FRα expression. The use according to claim 68, the method according to claim 69, the ligand-drug conjugate or its pharmaceutically acceptable salt or pharmaceutical composition according to claim 70, wherein the compound or its tautomer, meso compound, racemic mixture, enantiomer, diastereomer, or mixture thereof, or its pharmaceutically acceptable salt, or the pharmaceutical composition thereof, is characterized in that, The tumor is selected from the group consisting of: lung cancer, breast cancer, rectal cancer, colon cancer, esophageal cancer, gastric cancer, liver cancer, gallbladder cancer, bile duct cancer, kidney cancer, bladder cancer, urothelial carcinoma, head and neck cancer, nasopharyngeal carcinoma, prostate cancer, cervical cancer, endometrial cancer, ovarian cancer, pancreatic cancer, melanoma, bone cancer, mesothelioma, gastrointestinal stromal tumor, sarcoma, glioma, thyroid cancer, salivary gland tumor, glioblastoma, neuroblastoma, gastric mucinoma, lymphoma, leukemia, plasmacytoma, sinoatrial node cell tumor, giant cell tumor of the tendon sheath, brain cancer, squamous cell carcinoma, epidermal carcinoma, and non-Hodgkin's lymphoma; preferably, the cancer is selected from breast cancer, prostate cancer, lung cancer, pancreatic cancer, ovarian cancer, cervical cancer, endometrial cancer, bladder cancer, glioma, malignant lymphoma, liver cancer, and leukemia; Preferably, the tumor is pancreatic cancer, colorectal cancer, lung cancer, stomach cancer, or breast cancer. A kit comprising a ligand-drug conjugate or a pharmaceutically acceptable salt thereof according to any one of claims 1-28, a compound or a tautomer, meso compound, racemic compound, enantiomer, diastereomer, or mixture thereof thereof, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition according to claim 67.

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