Camptothecin compound, antibody drug conjugate as well as preparation method and application of antibody drug conjugate

Abstract

The invention provides a camptothecin compound, an antibody drug conjugate as well as a preparation method and application of the camptothecin compound and the antibody drug conjugate. Specifically, the invention provides a camptothecin compound shown as a formula K or a pharmaceutically acceptable salt thereof. The camptothecin compound and the antibody drug conjugate thereof provided by the invention have good cytotoxic activity and can inhibit proliferation of tumor cells. # imgabs0 #

Description

[0001] This application claims the priority of Chinese Patent Application No. 2023109020423 filed on July 20, 2023 and Chinese Patent Application No. 2023116319073 filed on November 30, 2023. This application cites the entire text of the above Chinese patent application. Technical Field

[0002] The present invention relates to the field of biomedicine, and in particular to a camptothecin compound, an antibody-drug conjugate, and a preparation method and application thereof. Background Art

[0003] Camptothecin (CPT) and its derivatives are one of the important traditional anti-tumor drug families, which have attracted widespread attention due to their unique mechanism of action (selective inhibition of DNA topoisomerase I). Currently, three camptothecin derivatives have been approved for marketing for tumor treatment (irinotecan, topotecan and belotecan). In addition, there are many camptothecin derivatives, such as Gimatecan, Karenitecin, Rubitecan, Silatecan, Exatecan, Lurtotecan and Simmitecan, which are in different clinical trial stages.

[0004] Antibody-drug conjugates (ADCs) combine the high specificity of monoclonal antibody drugs with the high activity of compound cytotoxic drugs to improve the targeting of tumor drugs and reduce toxic side effects. The emergence of ADC drugs fills the gap between antibody drugs and traditional chemotherapy drugs, improves the specificity of drugs and improves the therapeutic window. Enhertu, approved in 2019, and Trodelvy, approved in 2020, are both ADC drugs with camptothecin derivatives as effector molecules. However, further development of camptothecin derivatives and ADC drugs with better efficacy and / or safety is still needed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the single structure of existing camptothecin compounds and antibody-drug conjugates, and to provide a camptothecin compound, antibody-drug conjugate and its preparation method and application. The camptothecin compound and antibody-drug conjugate provided by the present invention have good cytotoxic activity and can inhibit the proliferation of tumor cells.

[0006] The present invention solves the above technical problems through the following solutions.

[0007] The present invention provides a camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof:

[0008]

[0009] Among them, R 1 C 1-6 alkyl;

[0010] R 2 is a halogen;

[0011] A is CH or N;

[0012] n is 0, 1, 2 or 3.

[0013] In a certain embodiment, the camptothecin compound or a pharmaceutically acceptable salt thereof as shown in Formula K satisfies one or more of the following conditions:

[0014] (1)R 1 In the C 1-6 Alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl; for example, methyl;

[0015] (2)R 2 wherein the halogen is fluorine, chlorine, bromine or iodine; for example, fluorine;

[0016] (3) for

[0017] In one scheme, R 1 is methyl, R 2 is fluorine, chlorine, bromine or iodine, for example fluorine.

[0018] In one plan, for Preferably

[0019]

[0020] In one embodiment, n is 0, 1 or 2.

[0021] In one embodiment, the camptothecin compound represented by formula K is a compound represented by formula K-1 or a compound represented by formula K-2;

[0022]

[0023] Wherein, A and n are independently as described in any embodiment of the present invention.

[0024] In one embodiment, the camptothecin compound as shown in formula K or a pharmaceutically acceptable salt thereof, wherein the camptothecin compound as shown in formula K is selected from any of the following structures:

[0025]

[0026]

[0027] The present invention also provides a linker-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula I:

[0028]

[0029] wherein Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, a tetrapeptide residue or a pentapeptide residue;

[0030] X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -、-(OCH2CH2) m -、-(CR a R b ) m -、-O(CR a R b ) m -、-NH-(CR a R b ) m -CR c R d -or-S(CR a R b ) m -CR c R d -;

[0031] R a and R b are independently H, D, halogen, C 1-6 Alkyl, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, C 1-6 Alkoxy, hydroxy, amino, cyano, nitro, 3-10 membered cycloalkyl or 3-10 membered heterocyclic group;

[0032] Or, R a and R b Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group;

[0033] R c and R d Independently H, C 1-6 Alkyl, halogen, halogenated C 1-6 Alkyl, deuterated C1-6 Alkyl, 3-10 membered cycloalkyl, 3-10 membered heterocyclyl, 6-14 membered aryl or 5-10 membered heteroaryl;

[0034] Or, R c and R d Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group;

[0035] The heteroatoms in each 3-10 membered heterocyclyl and 5-10 membered heteroaryl are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3;

[0036] Y is

[0037] R 4 C 1-6 Alkyl or one or more C 1-6 Alkyl substituted phenyl;

[0038] m, p, q and r are independently integers from 0 to 14;

[0039] R 1 , R 2 , A and n are defined as described in any embodiment of the present invention.

[0040] In a certain scheme, in X, -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -for-(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -*, where the -* end is connected to the carbonyl group ( The carbonyl group is connected.

[0041] In one embodiment, in the linker-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula I,

[0042] Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, a tetrapeptide residue or a pentapeptide residue;

[0043] X is -(CR a R b ) r -CO-NH-(CRa R b ) q -(OCH2CH2) p -*,*-(OCH2CH2) m -、-(CR a R b ) m -、*-O(CR a R b ) m -、*-NH-(CR a R b ) m -CR c R d -or*-S(CR a R b ) m -CR c R d -, where the * end (-* or *-) and the carbonyl ( Carbonyl) connection;

[0044] R a and R b are independently H, D, halogen, C 1-6 Alkyl, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, C 1-6 Alkoxy, hydroxy, amino, cyano, nitro, 3-10 membered cycloalkyl or 3-10 membered heterocyclic group;

[0045] Or, R a and R b Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group;

[0046] R c and R d Independently H, C 1-6 Alkyl, halogen, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, 3-10 membered cycloalkyl, 3-10 membered heterocyclyl, 6-14 membered aryl or 5-10 membered heteroaryl;

[0047] Or, R c and R d Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group;

[0048] The heteroatoms in each 3-10 membered heterocyclyl and 5-10 membered heteroaryl are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3;

[0049] Y is

[0050] R 4 C 1-6 Alkyl or one or more C 1-6 Alkyl substituted phenyl;

[0051] m, p1, q1, r1, p, q and r are independently integers from 0 to 14;

[0052] R 1 , R 2 , A and n are defined as described in any embodiment of the present invention.

[0053] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof is:

[0054]

[0055] wherein Q is a single amino acid residue, a dipeptide residue, a tripeptide residue or a tetrapeptide residue;

[0056] X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -、-(OCH2CH2) m -、-(CR a R b ) m -、-O(CR a R b ) m -、-NH-(CR a R b ) m -CR c R d -or-S(CR a R b ) m -CR c R d -;

[0057] R a and R b are independently H, D, halogen, C 1-6 Alkyl, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, C 1-6 Alkoxy, hydroxy, amino, cyano, nitro, 3-10 membered cycloalkyl or 3-10 membered heterocyclic group;

[0058] Or, R a and R b Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group;

[0059] R c and R d Independently H, C 1-6 Alkyl, halogen, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, 3-10 membered cycloalkyl, 3-10 membered heterocyclyl, 6-14 membered aryl or 5-10 membered heteroaryl;

[0060] Or, R c and R d Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group;

[0061] The heteroatoms in each 3-10 membered heterocyclyl and 5-10 membered heteroaryl are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3;

[0062] Y is

[0063] m, p, q and r are independently integers from 0 to 14;

[0064] R 1 , R 2 , A and n are defined as described in any embodiment of the present invention.

[0065] In a certain embodiment, the amino acid residues (the amino acid residues are the above-mentioned single amino acid residues or the amino acid residues constituting the dipeptide residue, tripeptide residue, tetrapeptide residue or pentapeptide residue) are independently -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Glu-, -Ile-, -Arg-, -Trp- or -Gly-.

[0066] In one embodiment, the dipeptide residue is -Lys-Phe-, -Ala-Val-, -Lys-Val-, -Lys-Ala-, -Cit-Val-, -Cit-Phe-, -Cit-Leu-, Cit-Ile-, -Arg-Phe-, -Cit-Trp- or -Val-Gly-, for example -Ala-Val-.

[0067] In one embodiment, the tripeptide residue is -Ala-Val-Glu-, -Cit-Val-Glu-, -Ala-Val-αGlu- or -Cit-Val-αGlu-.

[0068] In one embodiment, the tetrapeptide residue is -Gly-Phe-(Gly)2- or -(Gly)2-Phe-Gly-, for example -Gly-Phe-(Gly)2-, preferably in Connected to -NH- group.

[0069] In one scenario, R a , R b , R c and R d wherein the halogen is independently fluorine, chlorine, bromine or iodine.

[0070] In one scenario, R a , R b , R c and R d In the C 1-6 Alkyl, halogenated C 1-6 Alkyl and deuterated C 1-6 Any of the C 1-6 The alkyl group is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

[0071] In one scenario, R a , R b , R c and R d wherein the halogenated C 1-6 The alkyl groups are independently C 1-6 The halogen is preferably independently fluorine, chlorine, bromine or iodine.

[0072] In one scenario, R a , R b , R c and R d In the deuterated C 1-6 The alkyl groups are independently C substituted with 1, 2 or 3 deuterium (D) 1-6 alkyl.

[0073] In one scenario, R a , R b , R c and R d wherein the 3-10 membered cycloalkyl group is independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

[0074] In one scenario, R a , R b , R c and R dIn the above, the 3-10 membered heterocyclic group is independently a 3-6 membered heterocyclic group, and the heteroatoms of the 3-6 membered heterocyclic group are preferably independently selected from one, two or three of N, O or S, and the number of heteroatoms is preferably independently 1, 2 or 3.

[0075] In one scenario, R a and R b When the carbon atoms to which they are attached form a 3-10 membered cycloalkyl group, the 3-10 membered cycloalkyl group is independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

[0076] In one scenario, R a and R b When a 3-10 membered heterocyclic group is formed together with the carbon atom to which it is connected, the 3-10 membered heterocyclic group is independently a 3-6 membered heterocyclic group, and the heteroatoms of the 3-6 membered heterocyclic group are preferably independently selected from one, two or three of N, O or S, and the number of heteroatoms is preferably independently 1, 2 or 3.

[0077] In one scenario, R c and R d wherein the 6-14 membered aryl groups are independently phenyl or naphthyl.

[0078] In one scenario, R c and R d In the above, the 5-10 membered heteroaryl group is independently a 5-6 membered heteroaryl group, and the heteroatoms of the 5-6 membered heteroaryl group are preferably independently selected from one, two or three of N, O or S, and the number of heteroatoms is preferably independently 1, 2 or 3.

[0079] In one scenario, R 4 In the C 1-6 Alkyl and one or more C 1-6 Any of the C 1-6 Alkyl is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, for example methyl.

[0080] In one embodiment, X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -*,*-(OCH2CH2) m -、-(CR a R b ) m -、*-O(CR a R b) m -、*-NH-(CR a R b ) m -CR c R d -or*-S(CR a R b ) m -CR c R d -, where the * terminal group (*- or -*) and the carbonyl group ( The carbonyl group is connected.

[0081] In one scheme, Y is in Connect the X end.

[0082] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0083] (1) Each halogen is independently fluorine, chlorine, bromine or iodine;

[0084] (2) Each C 1-6 Alkyl is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl;

[0085] (3) Each C 1-6 Alkoxy is independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy;

[0086] (4) each 3-10 membered cycloalkyl group is independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl;

[0087] (5) Each 3-10 membered heterocyclic group is independently a 3-6 membered heterocyclic group, the heteroatoms of the 3-6 membered heterocyclic group are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3;

[0088] (6) Each 6-14 membered aryl group is independently phenyl or naphthyl;

[0089] (7) each 5-10 membered heteroaryl group is independently a 5-6 membered heteroaryl group, the heteroatoms of the 5-6 membered heteroaryl group are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3;

[0090] (8) In Q, the single amino acid residue is -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Ile-, -Arg-, -Trp- or -Gly-;

[0091] (9) In Q, the dipeptide residue is C＝O -Lys-Phe- NH , C＝O -Ala-Val- NH , C＝O -Lys-Val- NH , C＝O -Lys-Ala- NH , C＝O -Cit-Val- NH , C＝O Cit-Phe- NH , C＝O -Cit-Leu- NH , C＝O Cit-Ile- NH , C＝O -Arg-Phe- NH , C＝O -Cit-Trp- NH or C＝O -Val-Gly- NH ;For example C＝O -Ala-Val- NH ;

[0092] (10) In Q, the tripeptide residue is C＝O -Ala-Val-Glu- NH , C＝O -Cit-Val-Glu- NH , C＝O -Ala-Val-αGlu- NH or C＝O -Cit-Val-αGlu- NH ;and

[0093] (11) In Q, the tetrapeptide residue is C＝O -Gly-Phe-(Gly)2- NH or C＝O (Gly)2-Phe-Gly- NH ,For example C＝O -Gly-Phe-(Gly)2- NH .

[0094] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0095] (1)R a and R b is H;

[0096] (2) m is 1, 2, 3, 4 or 5;

[0097] (3) p is 8, 9, 10, 11, 12, 13 or 14;

[0098] (4) q is 1, 2, 3, 4 or 5;

[0099] (5) r is 1, 2, 3, 4 or 5;

[0100] (6) Q is a dipeptide residue or a tetrapeptide residue; for example C＝O -Ala-Val- NH or C＝O -Gly-Phe-(Gly)2- NH ;and

[0101] (7)X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -or-(CR a R b ) m -;For example Another example The "1" bit is connected to Y, and the "2" bit is connected to connect.

[0102] In one embodiment, the linker-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula I is characterized in that it satisfies one or more of the following conditions:

[0103] (1)R a and R b independently H;

[0104] (2) m is 5;

[0105] (3) p is 8;

[0106] (4)q is 2;

[0107] (5) r is 2;

[0108] (6)n is 0 or 1;

[0109] (7) The single amino acid residue is -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Ile-, -Arg- or -Trp-;

[0110] (8) The dipeptide residue is C＝O-Lys-Phe- NH , C＝O -Ala-Val- NH , C＝O -Lys-Val- NH , C＝O -Lys-Ala- NH , C＝O -Cit-Val- NH , C＝O Cit-Phe- NH , C＝O -Cit-Leu- NH , C＝O Cit-Ile- NH , C＝O -Arg-Phe- NH , C＝O -Cit-Trp- NH or C＝O -Val-Gly- NH ;

[0111] (9) The tripeptide residue is C＝O -Ala-Val-Glu- NH , C＝O -Cit-Val-Glu- NH , C＝O -Ala-Val-αGlu- NH or C＝O -Cit-Val-αGlu- NH ;

[0112] (10) The tetrapeptide residue is C＝O -Gly-Phe-(Gly)2- NH or C＝O (Gly)2-Phe-Gly- NH .

[0113] In one embodiment, Q is a tetrapeptide residue, preferably -Gly-Phe-(Gly)2- (e.g. C＝O -Gly-Phe-(Gly)2- NH ,in" C＝O -" refers to the carbonyl-linked end).

[0114] In one embodiment, X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CRa R b ) m -, preferably, X is -(CR a R b ) m -, where the -* end is connected to the carbonyl group ( The carbonyl group is connected.

[0115] In one scheme, R a and R b For H.

[0116] In one embodiment, m is an integer of 0-8, such as 5, 6, 7 or 8, preferably 5.

[0117] In one embodiment, p is an integer of 0-10, such as 5, 6, 7 or 8, preferably 8.

[0118] In one embodiment, q and r are independently integers from 0 to 8, such as 2 or 3.

[0119] In one solution, Y is in Connect the X end.

[0120] In one plan, for

[0121] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof;

[0122] Among them, Q is a tetrapeptide residue;

[0123] X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CR a R b ) m -*, wherein the -* end is connected to a carbonyl group;

[0124] R a and R b is H;

[0125] Y is

[0126] R 4 C 1-6 alkyl;

[0127] m is 5;

[0128] P is 8;

[0129] q and r are independently 2 or 3;

[0130] R 1 , R 2 , A and n are defined as described in any embodiment of the present invention.

[0131] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof;

[0132] Among them, Q is a tetrapeptide residue;

[0133] X is -(CR a R b ) m -;

[0134] R a and R b independently H;

[0135] Y is

[0136] m is 5;

[0137] for R 1 , R 2 , A and n are defined as described in any embodiment of the present invention.

[0138] In one embodiment, in the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof,

[0139] R 1 C 1-6 alkyl;

[0140] R 2 is a halogen;

[0141] A is CH or N;

[0142] n is 0, 1, 2 or 3;

[0143] for Q is a single amino acid residue, a dipeptide residue, a tripeptide residue or a tetrapeptide residue;

[0144] X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CRa R b ) m -*, wherein the -* terminal group is connected to the carbonyl group; R a and R b is H;

[0145] Y is R 4 C 1-6 alkyl;

[0146] m is an integer from 0 to 8;

[0147] p is an integer from 0 to 10;

[0148] q and r are independently integers of 0-8.

[0149] In one plan, for

[0150] In one plan, for

[0151] In one plan, for

[0152] in The end is connected to -O-.

[0153] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof, wherein the linker-drug conjugate as shown in Formula I is any of the following structures:

[0154]

[0155]

[0156] The present invention also provides an antibody-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula II:

[0157]

[0158] Among them, G L For antibodies;

[0159] t is the drug-ligand coupling ratio;

[0160] Z is The b end is connected to X, and the a end is connected to G L connect; R 1 , R 2, A and n are defined as described in any embodiment of the present invention;

[0161] The definitions of Q and X are as described in any embodiment of the present invention.

[0162] In one scheme, G L is an anti-HER2 antibody, such as trastuzumab, preferably L It is connected to Z via a thioether (-S-) bond.

[0163] In the antibody drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula II, t is a conventional conjugation ratio of such antibody drug conjugates in the art, for example, t is 1-8 (natural number and / or decimal), for example 7, 7.7 or 7.8.

[0164] In one embodiment, the antibody-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula II is:

[0165]

[0166] Among them, G L For antibodies;

[0167] t is the drug-ligand coupling ratio;

[0168] Z is The b end is connected to X, and the a end is connected to G L connect;

[0169] R 1 , R 2 , A and n are defined as described in any embodiment of the present invention;

[0170] The definitions of Q and X are as described in any embodiment of the present invention.

[0171] In one embodiment, the antibody drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0172] (1) G L Anti-HER2 antibodies, such as trastuzumab;

[0173] (2) t is a natural number and / or decimal between 1 and 8; for example, a natural number and / or decimal between 7 and 8; for example, 7.8; or t is a natural number between 1 and 8; for example, t is a natural number between 7 and 8; and

[0174] (3) the a-end of the Z and the G L Connected by thioether bonds.

[0175] In one embodiment, in the antibody-drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof,

[0176] Z is The b end is connected to X, and the a end is connected to G L connect;

[0177] G L is an antibody (e.g., an anti-HER2 antibody);

[0178] t is 1-8;

[0179] R 1 , R 2 ,A,n, Q and X are as described in any embodiment of the present invention.

[0180] In a certain embodiment, the antibody-drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof, wherein the antibody-drug conjugate as shown in Formula II is any of the following structures:

[0181]

[0182] The HER2 antibody is trastuzumab.

[0183] In one embodiment, the antibody drug conjugate shown in formula II is any of the following structures:

[0184]

[0185] The anti-HER2 antibody is trastuzumab.

[0186] The present invention provides a method for preparing an antibody-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula II, comprising the following steps: subjecting a linker-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula I to a coupling reaction with an antibody to obtain an antibody-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula II;

[0187]

[0188] Among them, R 1 , R 2 ,A,n, Q, X, R a , R b , Z, G L , t, m, p, q and r are independently as described in any embodiment of the present invention.

[0189] The present invention provides a method for preparing the camptothecin compound or a pharmaceutically acceptable salt thereof as shown in Formula K, which is Scheme 1 or Scheme 2;

[0190] Scheme 1 comprises the following steps: in a halogenated alkane solvent (e.g., dichloromethane), in the presence of a catalyst (e.g., copper tetraacetonitrile hexafluorophosphate), a compound represented by formula Ka and an azide compound represented by formula Kb are subjected to a cyclization reaction to obtain a compound represented by formula K;

[0191]

[0192] Where A is N;

[0193] R 1 , R 2 and n is as described in any embodiment of the present invention;

[0194] Scheme 2 comprises the following steps: in an aromatic hydrocarbon solvent (such as toluene), in the presence of an organic acid (such as acetic acid), a compound represented by formula Kc and a compound represented by formula Kd are subjected to a cyclization reaction to obtain a compound represented by formula K;

[0195]

[0197] Wherein, A is CH;

[0198] R 1 , R 2 and n are as described in any embodiment of the present invention.

[0199] The present invention also provides a compound as shown in formula Ka or a pharmaceutically acceptable salt thereof;

[0200]

[0201] Among them, R 1 , R 2 As described in any scheme of the present invention.

[0202] Preferably, the compound as shown in formula Ka is

[0203] The present invention also provides a compound as shown in formula Kc or a pharmaceutically acceptable salt thereof;

[0204]

[0205] Among them, A is CH, R 1 , R 2 and n are as described in any embodiment of the present invention.

[0206] Preferably, the compound represented by formula Kc is any of the following compounds:

[0207]

[0208] The present invention also provides a pharmaceutical composition, comprising a camptothecin compound as shown in formula K or a pharmaceutically acceptable salt thereof, a linker-drug conjugate as shown in formula I or a pharmaceutically acceptable salt thereof, or an antibody-drug conjugate as shown in formula II or a pharmaceutically acceptable salt thereof as described in any embodiment of the present invention, and pharmaceutical excipients.

[0209] The present invention also provides a use of a camptothecin compound as shown in formula K or a pharmaceutically acceptable salt thereof, a linker-drug conjugate as shown in formula I or a pharmaceutically acceptable salt thereof, or an antibody-drug conjugate as shown in formula II or a pharmaceutically acceptable salt thereof, or the above-mentioned pharmaceutical composition as described in any embodiment of the present invention in the preparation of a drug for preventing and / or treating cancer.

[0210] The cancer is preferably breast cancer, lung cancer (such as lung adenocarcinoma), kidney cancer, liver cancer, ovarian cancer, urethral cancer, prostate cancer, glioblastoma multiforme, pancreatic cancer, colorectal cancer, gastrointestinal stromal tumors, cervical cancer, squamous cell carcinoma, peritoneal cancer, colon cancer, rectal cancer, uterine cancer, salivary gland cancer, kidney cancer, vulvar cancer, thyroid cancer, penile cancer, leukemia, malignant lymphoma, plasmacytoma, myeloma, sarcoma, melanoma, bladder cancer, gastric cancer or esophageal cancer, preferably breast cancer or preferably lung adenocarcinoma, gastric cancer or colon cancer, such as gastric cancer, lung cancer, colon cancer or breast cancer.

[0211] Definition of terms

[0212] The stereochemical definitions and conventions used in the present invention generally follow SP Parker, Ed., McGraw-Hill Dictionary of Chemical Terms (1984) McGraw-Hill Book Company, New York; and Eliel, E. and Wilen, S., "Stereochemistry of Organic Compounds", John Wiley & Sons, Inc., New York, 1994.

[0213] Depending on the choice of starting materials and process, the compounds of the invention may exist in the form of one of the possible isomers or a mixture thereof, such as a racemate and a diastereomeric mixture (depending on the number of asymmetric carbon atoms). Optically active (R)- or (S)-isomers may be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques.

[0214] Any resulting mixture of stereoisomers can be separated into the pure or substantially pure geometric isomers, enantiomers, diastereomers on the basis of the differences in the constituent physicochemical properties, for example, by chromatography and / or fractional crystallization.

[0215] In this specification, groups and substituents thereof can be selected by those skilled in the art to provide stable structural moieties and compounds. When substituents are described by conventional chemical formulas written from left to right, the substituents also include chemically equivalent substituents obtained when the structural formula is written from right to left.

[0216] It will be understood by those skilled in the art that the structural formulas used in the present invention to describe groups are based on the conventions used in the art. It means that the corresponding group is connected to other fragments and groups in the compound through this site.

[0217] In the present invention, a substituent used may be preceded by a single dash "-" to indicate that the named substituent is connected to the parent moiety via a single bond. For example, CH3-C(=O)- means that the C(=O) in the acetyl group is connected to the parent moiety via a single bond.

[0218] The term "halogen" refers to fluorine, chlorine, bromine or iodine.

[0219] The term "alkyl" refers to a straight or branched chain alkyl group having a specified number of carbon atoms (e.g., C1 to C6). Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and the like.

[0220] In the present application, the term "alkoxy" as a group or part of another group refers to -O-alkyl, and alkyl is as defined above.

[0221] The term "cycloalkyl" refers to a cycloalkyl radical having a specified number of carbon atoms (e.g. 3-6 , C 3-10 ) is a saturated monocyclic ring group consisting of only carbon atoms. Cycloalkyl includes, but is not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0222] The term "heterocyclyl" refers to a cyclic group having a specified number of ring atoms (e.g., 5-10 members, 3-10 members), a specified number of heteroatoms (e.g., 1, 2, or 3), a specified heteroatom type (one or more of N, O, and S), which is a monocyclic, bridged, or spirocyclic ring, and each ring is saturated. Heterocycloalkyl includes, but is not limited to, azetidinyl, tetrahydropyrrolyl, tetrahydrofuranyl, morpholinyl, piperidinyl, and the like.

[0223] The term "aryl" refers to a radical having a specified number of carbon atoms (e.g. 6-10 , C 6-14) and is composed only of carbon atoms, which is monocyclic or polycyclic, and at least one ring is aromatic (in accordance with Huckel's rule). The aryl group is connected to other fragments in the molecule through an aromatic ring or a non-aromatic ring. The aryl group includes, but is not limited to, phenyl, naphthyl, etc.

[0224] The term "heteroaryl" refers to a cyclic group with a specified number of ring atoms (e.g., 5 to 10 members), a specified number of heteroatoms (e.g., 1, 2, or 3), a specified type of heteroatoms (one or more of N, O, and S), which is monocyclic or polycyclic, and at least one ring is aromatic (in accordance with Huckel's rule). The heteroaryl group is connected to other fragments in the molecule through an aromatic ring or a non-aromatic ring. Heteroaryl includes, but is not limited to, furanyl, pyrrolyl, thienyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, pyridyl, pyrimidinyl, indolyl, and the like.

[0225] The term "pharmaceutically acceptable salt" refers to a salt obtained by reacting a compound with a pharmaceutically acceptable (relatively non-toxic, safe, and suitable for use by patients) acid or base. When the compound contains a relatively acidic functional group, a base addition salt can be obtained by contacting the free form of the compound with a sufficient amount of a pharmaceutically acceptable base in a suitable inert solvent. When the compound contains a relatively basic functional group, an acid addition salt can be obtained by contacting the free form of the compound with a sufficient amount of a pharmaceutically acceptable acid in a suitable inert solvent.

[0226] The term "pharmaceutical excipients" refers to excipients and additives used in the production of drugs and the preparation of prescriptions. It is all substances contained in drug preparations except active ingredients. For details, please refer to the Pharmacopoeia of the People's Republic of China (2020 edition) or Handbook of Pharmaceutical Excipients (Raymond C Rowe, 2009).

[0227] The term "treat" refers to therapeutic treatment. When referring to a specific condition, treatment means: (1) ameliorating the disease or one or more biological manifestations of the condition, (2) interfering with (a) one or more points in the biological cascade leading to or causing the condition or (b) one or more biological manifestations of the condition, (3) ameliorating one or more symptoms, effects, or side effects associated with the condition or one or more symptoms, effects, or side effects associated with the condition or its treatment, or (4) slowing the progression of the condition or one or more biological manifestations of the condition.

[0228] The term "prevent" refers to the reduction of the risk of acquiring or developing a disease or disorder.

[0229] The term "therapeutically effective amount" refers to an amount of a compound that is sufficient to effectively treat a disease or condition described herein when administered to a patient."Therapeutically effective amount" will vary depending on the compound, the condition and its severity, and the age of the patient to be treated, but can be adjusted as needed by those skilled in the art.

[0230] The term "patient" refers to any animal that is about to or has been administered the compound or composition according to the embodiments of the present invention, preferably a mammal, and most preferably a human. The term "mammal" includes any mammal. Examples of mammals include, but are not limited to, cattle, horses, sheep, pigs, cats, dogs, mice, rats, rabbits, guinea pigs, monkeys, humans, etc., with humans being the most preferred.

[0231] Without violating the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0232] The reagents and raw materials used in the present invention are commercially available.

[0233] The positive and progressive effect of the present invention is that the present invention provides a class of camptothecin compounds and antibody-drug conjugates thereof with novel structures, and the camptothecin compounds and antibody-drug conjugates thereof have excellent cytotoxic activity and can inhibit the proliferation of tumor cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0234] Figure 1 This is a graph showing the volume changes of gastric cancer tumor cells under the action of antibody-drug conjugates.

[0235] Figure 2 This is a graph showing the changes in mouse body weight under the action of antibody-drug conjugates.

[0236] Figure 3 This is a graph showing the volume changes of breast cancer tumor cells under the action of antibody-drug conjugates.

[0237] Figure 4 This is a graph showing the changes in mouse body weight under the action of antibody-drug conjugates. DETAILED DESCRIPTION

[0238] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0239] In the following examples, DMAP represents 4-dimethylaminopyridine; rac-BINAP represents 1,1'-binaphthyl-2,2'-bisdiphenylphosphine; and PBS represents phosphate buffered saline.

[0240] Preparation Example 1: Synthesis of Compound 10

[0241]

[0242] Under nitrogen protection, (2-bromoethoxy)(tert-butyl)diphenylsilane (22.5 g, synthesized with reference to Synlett 2014; 25 (19): 2802-2805) and 1H-pyrazole-4-carboxaldehyde (5.0 g commercially available) were dissolved in 100 mL of anhydrous N,N-dimethylformamide, potassium carbonate (8.6 g) was added at room temperature, and the mixture was heated to 85°C for 4 hours. TLC monitored the complete reaction of the raw materials and cooled to room temperature. 200 mL of water was added to quench the reaction, and the mixture was extracted with ethyl acetate, dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and separated by a chromatographic column to obtain compound 10, 12.8 g of a colorless oil, with a yield of 65%. 1 H NMR(400MHz, CDCl3)δ9.86(s,1H),8.02(s,1H),7.98(s,1H),7.54–7.48(m,4H) ,7.45–7.33(m,6H),4.27(t,J=5.1Hz,2H),4.00(t,J=5.1Hz,2H),1.00(s,9H).

[0243] Preparation Example 2: Synthesis of Compounds 10-1, 10-2, 10-3, 10-4 and 10-5

[0244]

[0245] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-1 was synthesized using (3-bromopropoxy)(tert-butyl)diphenylsilane (prepared by referring to the synthesis method of compound 67 in patent WO2022063278) and 1H-pyrazole-4-carboxaldehyde: 1 HNMR(400MHz, CDCl3)δ9.80(s,1H),7.94(s,1H),7.79(s,1H),7.69–7.61(m,4H),7.45–7 .36(m,6H),4.33(t,J=6.8Hz,2H),3.65(t,J=5.7Hz,2H),2.16–2.06(m,2H),1.09(s,9H).

[0246] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-2 was synthesized using (4-bromobutoxy)(tert-butyl)diphenylsilane (prepared by referring to the synthesis method of compound 70 in patent WO2022063278) and 1H-pyrazole-4-carboxaldehyde: 1HNMR(400MHz, CDCl3)δ9.83(s,1H),7.95(s,1H),7.85(s,1H),7.70–7.59(m,4H),7.43–7.36(m,6H ), 4.15 (t, J = 7.1Hz, 2H), 3.70 (t, J = 6.1Hz, 2H), 2.08–1.93 (m, 2H), 1.60–1.49 (m, 2H), 1.07 (s, 9H).

[0247] Referring to the synthesis method of compound 10 in Preparation Example 1, (2-bromoethoxy)(tert-butyl)diphenylsilane and 1H-pyrrolidone were used. Azole-3-carboxaldehyde (commercially available) synthesizes compound 10-3: 1 H NMR (400MHz, CDCl3) δ9.85 (s, 1H), 7.59 (d, J=

[0249] 2.0Hz,1H),7.52–7.48(m,4H),7.41–7.32(m,6H),6.90(d,J=2.0Hz,1H),4.74(t,J=5.5Hz,2H),3.98(t,J=5.5Hz,2H),0.95(s,9H).

[0250] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-4 was synthesized using (3-bromopropoxy)(tert-butyl)diphenylsilane and 1H-pyrazole-3-carboxaldehyde: 1 H NMR (400MHz, CDCl3) δ9.86 (s, 1H), 7.69–7.65 (m, 4H), 7.53 (d, J = 2.1Hz, 1H), 7.43–7.35 (m, 6H), 6.88(d,J=2.1Hz,1H),4.82–4.60(m,2H),3.71(t,J=6.0Hz,2H),2.13–2.03(m,2H),1.07(s,9H).

[0251] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-5 was synthesized using (4-bromobutoxy)(tert-butyl)diphenylsilane and 1H-pyrazole-3-carboxaldehyde: 1 H NMR (400MHz, CDCl3) δ9.85 (s, 1H), 7.68–7.65 (m, 4H), 7.55 (d, J = 2.0Hz, 1H), 7.43–7.37 (m, 6H), 6.88 (d, J = 2 .0Hz,1H),4.57(t,J=7.1Hz,2H),3.68(t,J=6.2Hz,2H),2.01–1.89(m,2H),1.61–1.51(m,2H),1.06(s,9H).

[0252] Example 1: Preparation of Compounds K1, K2 and K3

[0253]

[0254] Step 1: Synthesis of compound 2

[0255] Anhydrous N, N-dimethylformamide (100 mL), compound 1 (7.0 g commercially available), compound B (10.0 g, CAS: 110351-94-5, purchased from Shanghai Xiyao Pharmaceutical Technology Co., Ltd.) and iodine (0.96 g) were added to a 250 mL three-necked flask, and the mixture was heated to 80 ° C and stirred for 8 h under a nitrogen atmosphere. After TLC detected that the raw materials reacted completely, the reaction solution was slowly poured into a mixture of ice and water, and the solid was precipitated, filtered, and dried to obtain 10 g of compound 2 as a brown solid with a yield of 69%. 1 HNMR (400MHz, DMSO) δ8.59(s,1H),8.02(d,J=8.3Hz,1H),7.85(d,J=11.0Hz,1H),7.30(s,1H),6.52(s,1H) ,5.42(s,2H),5.21(s,2H),2.46(s,3H),1.95-1.79(m,2H),0.88(t,J=7.1Hz,3H).MS(ESI)m / z=381.1(M+H + )

[0256] Step 2: Synthesis of compound 3

[0257] Anhydrous dichloromethane (250 mL), compound 2 (2.50 g), DMAP (0.12 g), anhydrous pyridine (5.31 mL) and acetic anhydride (3.75 mL) were added to a 500 mL three-necked flask, and the mixture was stirred at room temperature for 8 h under a nitrogen atmosphere. After TLC detected that the reaction of the raw materials was complete, the reaction solution was washed with dilute hydrochloric acid, saturated sodium bicarbonate solution, and saturated sodium chloride solution in turn, separated, dried, and concentrated under reduced pressure to obtain 2.2 g of crude product compound 3, which was directly used in the next step without further purification.

[0258] Step 3: Synthesis of compound 4

[0259] Add acetic acid (50 mL) and compound 3 (2.0 g) to a 100 mL single-mouth bottle, stir at room temperature to dissolve, then add 30% hydrogen peroxide (5.0 mL), heat to 70°C and stir to react for 3 h. After TLC detection of the complete reaction of the raw materials, cool the reaction solution to room temperature, evaporate the acetic acid under reduced pressure, dissolve the residue in chloroform, wash with saturated sodium bicarbonate solution, purified water, and saturated sodium chloride solution in turn, separate the liquids, dry, and concentrate under reduced pressure to obtain 1.5 g of crude product compound 4, which is directly used in the next step without further purification.

[0260] Step 4: Synthesis of compound 5

[0261] Add anhydrous N, N-dimethylformamide (100 mL) and compound 4 (1.00 g) to a 100 mL single-mouth bottle. After complete dissolution, cool to 0 ° C, slowly drop oxalyl chloride (0.45 mL), and heat to room temperature and stir for 1 hour after the addition is complete. After TLC detection of the complete reaction of the raw materials, part of the N, N-dimethylformamide is evaporated under reduced pressure, and then the remaining reaction liquid is slowly poured into a mixture of ice and water to precipitate solids and filter. Dry and separate by chromatographic column to obtain compound 5 as a yellow solid of 0.8 g, with a yield of 80%. 1 H NMR (400MHz, CDCl3) δ8.14(d,J=7.8Hz,1H),7.82(d,J=10.3Hz,1H),7.16(s,1H),5.68(d,J=17.3Hz,1H),5.40(d,J=17.4Hz,1H),5. 29(s,2H),2.58(s,3H),2.33-2.24(m,1H),2.22(s,3H),2.14(dq,J=14.4,7.1Hz,1H),0.98(t,J=7.4Hz,3H).MS(ESI)m / z=457.1(M+H) + )

[0262] Step 5: Synthesis of compound 6

[0263] Anhydrous toluene (10 mL), compound 5 (3.0 g), anhydrous potassium carbonate (1.8 g), palladium acetate (0.14 g), rac-BINAP (0.81 g), and trimethylsilyl acetylene (3.71 mL) were added to a 100 mL sealed tube, and the nitrogen was replaced and the temperature was raised to 100 ° C. and stirred for 15 hours. After TLC detected that the raw materials reacted completely, the reaction solution was cooled to room temperature, the solvent was evaporated under reduced pressure, and compound 6 was obtained as a yellow solid of 3.0 g after separation by chromatographic column, with a yield of 88%. 1 H NMR (400MHz, CDCl3) δ8.12(d,J=7.9Hz,1H),7.78(d,J=10.4Hz,1H),7.15(s,1H),5.68(d,J=17.2Hz,1H),5.41(d,J=17.2Hz,1H),5.28(s,2 H),2.57(s,3H),2.33-2.25(m,1H),2.22(s,3H),2.14(td,J=15.0,7.6Hz,1H),0.98(t,J=7.4Hz,3H),0.40(s,9H).MS(ESI)m / z=518.2(M+H + )

[0264] Step 6: Synthesis of compound 7

[0265] Methanol (100 mL), compound 6 (3.0 g), potassium fluoride (1.34 g) and acetic acid (1.0 mL) were added to a 250 mL single-mouth bottle, and the mixture was stirred at room temperature for 2 h under a nitrogen atmosphere. After TLC detected that the reaction of the raw materials was complete, the solvent was evaporated under reduced pressure, and the residue was dissolved in chloroform, washed with purified water and saturated sodium chloride solution in turn, separated, dried, and concentrated under reduced pressure to obtain 2.8 g of crude product, which was recrystallized from ethanol to obtain 2.3 g of compound 7, with a yield of 90%. 1 H NMR (400MHz, CDCl3) δ8.17(d,J=8.2Hz,1H),7.81(d,J=10.1Hz,1H),7.16(s,1H),5.68(d,J=17.1Hz,1H),5.41(d,J=17.3Hz,1H),5.3 1(s,2H),4.03(s,1H),2.57(s,3H),2.34-2.24(m,1H),2.22(s,3H),2.19-2.10(m,1H),0.98(t,J=7.4Hz,3H).MS(ESI)m / z=447.1(M+H) + )

[0266] Step 7: Synthesis of compound 8

[0267] Concentrated sulfuric acid (10 mL) was added to a 10 mL single-mouth bottle, and compound 7 (1.0 g) was added after the temperature dropped to 0°C, and the mixture was heated to room temperature under nitrogen atmosphere and stirred for 1 h. After TLC detected that the reaction of the raw materials was complete, the reaction solution was slowly poured into a mixture of ice and water, and the pH was adjusted to neutral with a saturated sodium bicarbonate solution. The solid was precipitated, filtered, and dried to obtain 0.7 g of compound 8 with a yield of 80%. 1 H NMR (400MHz, DMSO) δ8.18(d,J=8.2Hz,1H),7.96(d,J=10.7Hz,1H),7.31(s,1H),6.55(s,1H),5.51(s,1H) ,5.44(s,2H),5.26(s,2H),2.53(s,3H),1.93-1.80(m,2H),0.88(t,J=7.3Hz,3H).MS(ESI)m / z=404.1(M+H + )

[0268] Step 8: Synthesis of Compound K1

[0269] Dichloromethane (10 mL), compound 8 (0.1 g), ethyl azido (0.03 g) and copper tetraacetonitrile hexafluorophosphate (0.02 g) were added to a 10 mL single-mouth bottle, and the mixture was stirred at room temperature for 1.5 h under a nitrogen atmosphere. After the reaction of the raw materials was complete, the reaction solution was washed with purified water and saturated sodium chloride solution, separated, dried, and concentrated under reduced pressure to obtain a crude product, which was separated by a chromatographic column to obtain 0.08 g of compound K1, with a yield of 65%. 1 H NMR (400MHz, DMSO) δ9.00(s,1H),8.49(d,J=8.0Hz,1H),7.94(d,J=10.6Hz,1H),7.34(s,1H),6.54(s,1H),5.44(s,2H),5.36(s,2H ),5.18(s,1H),4.64(s,2H),3.96(s,2H),2.50(s,3H),1.88(tt,J=14.4,7.1Hz,2H),0.89(t,J=7.0Hz,3H).MS(ESI)m / z=492.2(M+H + )

[0270] Referring to the above synthesis method, azidoethanol was replaced by azidopropanol and azidobutanol, respectively, to synthesize compound K2 and compound K3.

[0271]

[0272] K2: 1 H NMR (400MHz, DMSO) δ9.01 (s, 1H), 8.49 (d, J = 8.0Hz, 1H), 7.94 (d, J = 10.5

[0273] Hz,1H),7.33(s,1H),6.54(s,1H),5.44(s,2H),5.36(s,2H),4.60(t,J=7.0Hz,2H),4.53(t,J=5.0Hz,1H),3.48(d d,J=11.1,5.7Hz,2H),2.50(s,3H),2.00(m,2H),1.93-1.81(m,2H),0.89(t,J=7.0Hz,3H).MS(ESI)m / z=506.2(M+H + )

[0274]

[0275] K3: 1 H NMR (400MHz, DMSO) δ9.08 (s, 1H), 8.49 (d, J = 8.0Hz, 1H), 7.94 (d, J = 10.5

[0276] Hz,1H),7.33(s,1H),6.54(s,1H),5.44(s,2H),5.36(s,2H),4.60(t,J=7.0Hz,2H),4.53(t,J=5.0Hz,1H),3.48(dd,J=11.1,5. 7Hz,2H),2.50(s,3H),2.09-2.00(m,2H),1.93-1.81(m,2H),1.56-1.47(m,2H),0.89(t,J=7.0Hz,3H).MS(ESI)m / z=520.2(M+H + ).

[0277] Example 2: Preparation of compounds K4, K5, K6, K7, K8 and K9

[0278]

[0279] Step 1: Synthesis of compound 11

[0280] Under nitrogen protection, compound 9 (1.0 g, the synthesis method refers to Example 1 of patent CN111470998A) was dissolved in 15 mL of anhydrous tetrahydrofuran and cooled at -78°C for half an hour. A hexane solution of n-butyl lithium (2.5 M, 3.5 mL) was added dropwise at low temperature, and a solution of compound 10 (1.5 g) in anhydrous tetrahydrofuran (5 mL) was quickly added after the dropwise addition, and the reaction was continued at -78°C for one hour. After TLC detected that the raw material had reacted completely, the reaction was quenched with a saturated ammonium chloride solution, extracted with ethyl acetate, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated with a chromatographic column to obtain compound 11, 0.6 g of a light yellow oil, with a yield of 25%. 1 HNMR(400MHz, CDCl3) δ8.69(s,1H),7.95(d,J=11.6Hz,1H),7.52-7.28(m,14H),6.91(d,J=8.2Hz,1H),5.86( s,1H),4.24-4.13(m,2H),3.99-3.87(m,2H),2.15(s,3H),2.00(s,3H),0.96(s,9H).MS(ESI)m / z=546.3(M+H + )

[0281] Step 2: Synthesis of compound 12

[0282] Under nitrogen protection, compound 11 (0.6 g) was dissolved in 15 mL of acetonitrile, manganese dioxide (0.86 g) was added, and the mixture was heated under reflux for three hours. After TLC detected that the reaction of the raw material was complete, the mixture was filtered through diatomaceous earth, and the filtrate was dried and separated by a chromatographic column to obtain compound 12, 0.55 g of a colorless oil, with a yield of 92%. 1H NMR (400MHz, CDCl3) δ10.82(s,1H),8.39(d,J=12.4Hz,1H),7.99(s,1H),7.91(s,1H),7.62(d,J=8.3Hz,1H),7.55- 7.33(m,10H),4.30(t,J=5.0Hz,2H),4.03(t,J=5.0Hz,2H),2.27-2.15(m,6H),1.00(s,9H).MS(ESI)m / z=544.2(M+H + )

[0283] Step 3: Synthesis of compound 13

[0284] Under nitrogen protection, compound 12 (0.55 g) was dissolved in 10 mL of ethanol, 3 mL of concentrated hydrochloric acid was added, and the mixture was heated under reflux for 3 hours to precipitate a white solid. TLC monitored that the reaction of the raw material was complete, and the mixture was filtered and dried to obtain 0.19 g of compound 13, with a yield of 80%. The mixture was used directly in the next step without further purification.

[0285] Step 4: Synthesis of compound K4

[0286] Under nitrogen protection, compound 13 (0.19 g) and compound B (0.22 g) were dissolved in 10 mL toluene and 5 mL acetic acid, and heated to 100° C. to react overnight. TLC monitored the complete reaction of the raw materials, and the mixture was directly spin-dried and separated by a chromatographic column to obtain 0.28 g of white solid K4, with a yield of 80%. 1 H NMR (400MHz, DMSO) δ8.43(s,1H),8.16(d,J=8.2Hz,1H),8.08(s,1H),7.91(d,J=10.8Hz,1H),7.33(s,1H),5.42(s,2H),5.38-5.12(m ,2H),4.34(t,J=5.5Hz,2H),3.88(t,J=5.6Hz,2H),2.47(s,3H),2.00-1.73(m,2H),0.89(t,J=7.3Hz,3H).MS(ESI)m / z=491.2(M+H+).

[0287] Referring to the above synthesis method, compound 10 was replaced by compounds 10-1, 10-2, 10-3, 10-4 and 10-5, respectively, to synthesize compounds K5, K6, K7, K8 and K9.

[0288]

[0289]

[0290] K5: 1H NMR(400 MHz,DMSO)δ8.46(s,1H),8.11(d,J=8.3 Hz,1H),8.06(s,1H),

[0291] 7.88(d,J=10.8 Hz,1H),7.31(s,1H),6.50(s,1H),5.42(s,2H),5.33-5.12(m,2H),4.37(t,J=7.1 Hz,2H),3.51(t,J=6.1 Hz,2H),2.46(s,3H),2.17-1.99(m,2H),1.96-1.72(m,2H),0.89(t,J=7.3 Hz,3H).MS(ESI)m / z=505.2(M+H + )。

[0292]

[0293] K6: 1 H NMR(400 MHz,DMSO)δ8.45(s,1H),8.13(d,J=8.3 Hz,1H),8.07(s,1H),7.90

[0294] (d,J=10.8 Hz,1H),7.32(s,1H),5.41(s,2H),5.34-5.16(m,2H),4.39(t,J=7.1Hz,1H),3.50(t,J=6.1 Hz,2H),2.47(s,3H),2.09-2.00(m,2H),1.93-1.71(m,2H),1.56-1.47(m,2H),0.88(t,J=7.3 Hz,3H).MS(ESI)m / z=519.2(M+H + )。

[0295]

[0296] K7: 1 H NMR(400 MHz,DMSO)δ8.33(d,J=5.2 Hz,1H),8.12(d,J=8.2 Hz,1H),8.02

[0297] (d,J=5.2 Hz,1H),7.91(d,J=10.8 Hz,1H),7.30(s,1H),5.41(s,2H),5.33-5.11(m,2H),4.32(t,J=5.4 Hz,2H),3.86(t,J=5.5 Hz, 2H), 2.47 (s, 3H), 1.98-1.72 (m, 2H), 0.89 (t, J = 7.3Hz, 3H). MS (ESI) m / z = 491.2 (M+H+).

[0298]

[0299] K8: 1 H NMR (400MHz, DMSO) δ8.31(d,J=5.2Hz,1H),8.14(d,J=8.2Hz,1H),8.04

[0300] (d,J=5.2Hz,1H),7.93(d,J=10.8Hz,1H),7.32(s,1H),5.44(s,2H),5.32–5.10(m,2H),4.34(t,J=5.4Hz,2H),3.82 (t,J=5.5Hz,2H),2.45(s,3H),2.14–1.96(m,2H),1.98–1.72(m,2H),0.89(t,J=7.3Hz,3H).MS(ESI)m / z=505.2(M+H + ).

[0301]

[0302] K9: 1 H NMR (400MHz, DMSO) δ8.36(d,J=5.2Hz,1H),8.15(d,J=8.2Hz,1H),8.02

[0303] (d,J=5.2Hz,1H),7.91(d,J=10.8Hz,1H),7.30(s,1H),5.41(s,2H),5.33–5.11(m,2H),4.32(t,J=5.4Hz,2H),3.86(t,J=5.5 Hz,2H),2.47(s,3H),2.17–1.99(m,2H),1.98–1.72(m,2H),1.56–1.47(m,2H),0.89(t,J=7.3Hz,3H).MS(ESI)m / z=519.2(M+H + ).

[0304] Example 3: Preparation of Compounds I-1 and I-2

[0305]

[0306] Step 1: Preparation of compound 15

[0307] Under nitrogen protection, compound K4 (100 mg) and compound 14 (150 mg, CAS: 1599440-06-8, purchased from Haijieya (Chengdu) Pharmaceutical Technology Co., Ltd.) were dissolved in 10 mL of anhydrous tetrahydrofuran, p-toluenesulfonic acid pyridinium salt (25 mg) was added at room temperature, and the mixture was heated to 55°C for overnight reaction. The reaction was quenched with saturated sodium bicarbonate solution, extracted with ethyl acetate, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated by a chromatographic column to obtain compound 15 as a white solid (50 mg) with a yield of 30%.

[0308] 1 H NMR(400MHz,DMSO)δ8.76(t,J=6.6Hz,1H),8.40(s,1H),8.11–8.01(m,2H),7.85–7.77(m, 3H),7.65–7.55(m,3H),7.39–7.22(m,5H),6.52(s,1H),5.40(s,2H),5.22–5.05(m,2H),4. 63(d,J=6.6Hz,2H),4.46(t,J=5.2Hz,2H),4.25–4.18(m,2H),4.17–4.10(m,1H),3.90(t,J =5.4Hz,2H),3.65(d,J=6.0Hz,2H),2.42(s,3H),1.90–1.81(m,2H),0.89(t,J=7.3Hz,3H). MS(ESI)m / z=799.3(M+H + ).

[0309] Step 2: Preparation of compound 16

[0310] Under nitrogen protection, compound 15 (50 mg) was dissolved in 5 mL of anhydrous tetrahydrofuran, and diethylamine (0.5 mL) was added at room temperature. The mixture was reacted at room temperature for 2 hours, and solid was precipitated. TLC monitored the complete reaction of the raw material, filtered, and vacuum dried to obtain compound 16 as a light yellow solid of 30 mg, with a yield of 83%. It was used directly in the next step without further purification. MS (ESI) m / z = 577.2 (M+H + ).

[0311] Step 3: Preparation of Compound I-1

[0312] Under nitrogen protection, compound 17 (30 mg) was dissolved in 2 mL of anhydrous N, N-dimethylformamide, and 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride (18.5 mg) and N, N-diisopropylethylamine (10 μL) were added at room temperature, and the mixture was reacted at room temperature for 2 hours. After the reaction solution became clear, compound 16 (30 mg) was added at room temperature, and the mixture was reacted overnight at room temperature. LC-MS monitored that the reaction of raw material 16 was complete, and the mixture was directly spin-dried and purified by C18 reverse phase column to obtain compound I-1 as a light yellow solid of 27 mg with a yield of 50%.

[0313] 1 H NMR (400MHz, DMSO) δ8.57(t,J=6.6Hz,1H),8.45(s,1H),8.30(t,J=5.8Hz,1H),8.17–8.07(m,3H),8.04(t,J=5.7Hz,1H),7.99(t,J=5.6Hz,1H),7.9 0(d,J=10.7Hz,1H),7.33(s,1H),7.26–7.10(m,5H),6.98(s,2H),6.51(s ,1H),5.42(s,2H),5.35–5.18(m,2H),4.62(d,J=6.6Hz,2H),4.51–4.41(m ,3H),3.89(t,J=5.4Hz,2H),3.79–3.69(m,3H),3.67–3.63(m,2H),3.58( dd,J=16.7,5.4Hz,1H),3.35(t,J=7.1Hz,2H),3.01(dd,J=13.8,4.5Hz,1H ),2.76(dd,J=13.7,9.7Hz,1H),2.47(s,3H),2.09(t,J=7.4Hz,2H),1.94– 1.79(m,2H),1.52–1.39(m,4H),1.23–1.12(m,2H),0.88(t,J=7.3Hz,3H). MS(ESI)m / z=1031.4(M+H + ).

[0314] Referring to the preparation method of I-1, Compound K4 is replaced by Compound K1. Compound I-2 can be obtained by the same method as above.

[0315]

[0316] I-2: 1 H NMR(400MHz,DMSO)δ8.70(t,J=6.6Hz,1H),8.26(t,J=5.6Hz,1H),8.13

[0317] –8.10(m,2H),8.06(t,J=5.7Hz,1H),8.02(s,1H),7.92(t,J=5.7Hz,1H),7.71(d,J=7.3Hz,1H),7.36(s,1H),7. 31–7.25(m,2H),7.25–7.16(m,3H),6.92(s,2H),5.44(s,2H),5.24(s,2H),4.65–4.59(m,2H),4.56–4.34(m,3H ),4.23–4.18(m,2H),3.88(t,J=5.2Hz,2H),3.78–3.59(m,4H),3.36(t,J=7.1Hz,2H),3.17–2.88(m,2H),2.45( s,3H),2.14(t,J=7.5Hz,2H),1.91–1.75(m,2H),1.64–1.42(m,4H),1.32–1.05(m,2H),0.89(t,J=7.3Hz,3H).MS (ESI) m / z=1032.4(M+H + )。

[0318] Example 4: Synthesis of Compounds II-1 and II-2

[0319]

[0320] The HER2 antibody is trastuzumab.

[0321] At 37°C, add the prepared aqueous solution of tris(2-carboxyethyl)phosphine (TCEP) (10mM, 37.2μL, 372nmol) to the PBS buffer solution of antibody Trastuzumab (HER2 antibody, CAS: 180288-69-1, purchased from Hangzhou Haoyang Biotechnology Co., Ltd.) (pH = 6.5 0.05M PBS buffer solution; 10.0mg / mL, 1.0mL, 67.6nmol), place in a water bath oscillator, oscillate at 37°C for 3 hours, and then stop the reaction. Cool the reaction solution to 25°C with a water bath. Dissolve compound I-1 or I-2 (1014nmol) in 50μL DMSO, add to the above reaction solution, place in a water bath oscillator, oscillate at 25°C for 3 hours, and then stop the reaction. The reaction solution was desalted and purified using a Sephadex G25 gel column (mobile phase: 0.05 M PBS buffer solution at pH 6.5, containing 0.001 M EDTA) to obtain PBS buffer solution (1.1 mg / mL, 7.5 mL) of the conjugates II-1 and II-2, which were stored at 4°C.

[0322] The average drug loading values ​​calculated by RP-HPLC were: II-1, t=7.8; II-2, t=7.7.

[0323] Example 5: Preparation of Compound I-3

[0324]

[0325] Step 1: Preparation of compound 19

[0326] Under nitrogen protection, compound 18 (1.2 g, CAS: 236426-37-2, purchased from Jier Biochemical Co., Ltd.) was dissolved in anhydrous tetrahydrofuran (10 mL), and diethylamine (3 mL) was added at room temperature for 2 h. TLC detection showed that no raw material remained, and the reaction was stopped. The reaction solution was directly concentrated to dryness, and then dissolved in dichloromethane and concentrated to dryness to obtain crude compound 19, 0.7 g of viscous liquid, with a yield of 96.9%. MS (ESI) m / z = 336.2 (M+H+).

[0327] Step 2: Preparation of compound 21

[0328] Under nitrogen protection, compound 19 (0.7 g) was dissolved in acetonitrile (10 mL), and compound 20 (1.4 g, CAS: 756525-93-6, purchased from Zhejiang Ruiao Biotechnology Co., Ltd.) was added at room temperature, and heated to 55°C for overnight reaction. Saturated sodium bicarbonate solution, ethyl acetate extraction, saturated sodium chloride solution washing, anhydrous sodium sulfate drying, reduced pressure concentration and separation by chromatographic column to obtain compound 21, colorless liquid 1.3 g, yield 68.4%. MS (ESI) m / z = 910.5 (M+H+).

[0329] Step 3: Preparation of compound 22

[0330] Under nitrogen protection, compound 21 (1.3 g) was dissolved in dichloromethane (20 mL), trifluoroacetic acid (5 mL) was added at room temperature, and the mixture was heated to 35°C for overnight reaction. TLC detection showed that no raw material remained, and the reaction was stopped. The reaction solution was directly concentrated to dryness, and then the solvent was removed by dichloromethane. After reduced pressure concentration, compound 22 was separated by chromatographic column to obtain 0.8 g of colorless oil with a yield of 66.1%.

[0331] 1H NMR (400MHz, DMSO) δ8.17(t,J=5.6Hz,1H),8.12(d,J=8.0Hz,1H),8.01(q,J=5.6Hz,2H),7.31–7.25 (m,2H),7.22(dd,J=7.5,3.0Hz,3H),7.00(s,2H),5.75(s,2H),4.49–4.34(m,1H),3.79–3.65(m,5H ),3.61(dt,J=14.5,5.6Hz,5H),3.56–3.44(m,25H),3.37(t,J=5.8Hz,2H),3.17–3.12(m,2H),3.06 (dd, J = 13.8, 5.0 Hz, 1H), 2.90 (dd, J = 13.7, 9.0 Hz, 1H), 2.40 (t, J = 6.5 Hz, 2H), 2.34 (t, J = 7.3 Hz, 2H). MS(ESI)m / z=854.4(M+H+).

[0332] Step 4: Preparation of Compound I-3

[0333] Under nitrogen protection, compound 22 (100 mg) was dissolved in anhydrous tetrahydrofuran (15 mL), 1-hydroxybenzotriazole (HOBT) (20 mg) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (28 mg) were added at room temperature, and the mixture was reacted at room temperature for 2 hours. After the reaction solution became clear, compound 16 (70 mg) was added at room temperature, and the mixture was reacted overnight at room temperature. LC-MS monitored that the reaction of raw material 16 was complete, and after reduced pressure concentration, compound I-3 was separated by a chromatographic column to obtain a light yellow solid of 35 mg with a yield of 50%.

[0334] 1H NMR(400MHz,DMSO)δ8.59(t,J=6.4Hz,1H),8.46(s,1H),8.32(d,J=6.2Hz,1H),8 .14(dd,J=22.1,9.0Hz,3H),8.00(s,2H),7.93(d,J=10.7Hz,1H),7.35(s,1H),7 .19(dt,J=17.3,8.8Hz,5H),7.00(s,2H),6.54(s,1H),5.43(s,2H),5.31(s,2H) ,4.62(d,J=6.6Hz,2H),4.55-4.39(m,3H),3.89(t,J=5.2Hz,2H),3.83-3.66(m,4 H),3.59(t,J=6.4Hz,4H),3.55-3.42(m,21H),3.42-3.22(m,5H),3.15(dd,J=11 .7,6.0Hz,2H),3.07-2.92(m,2H),2.83-2.71(m,2H),2.38(t,J=6.5Hz,2H),2.33 (t,J=7.3Hz,2H),2.03(dd,J=20.8,13.2Hz,2H),1.87(dd,J=14.6,7.1Hz,3H),1 .28(d,J=28.2Hz,5H),0.88(dd,J=12.7,5.4Hz,3H).MS(ESI)m / z=1412.6(M+H+).

[0335] Example 6: Preparation of Compound I-4

[0336]

[0337] Step 1: Preparation of compound 24

[0338] Under nitrogen protection, compound 19 (300 mg) was dissolved in acetonitrile (10 mL), and compound 23 (820 mg, CAS: 1334170-03-4, purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.) was added at room temperature, and heated to 45°C for overnight reaction. Saturated sodium bicarbonate solution, ethyl acetate extraction, saturated sodium chloride solution washing, anhydrous sodium sulfate drying, reduced pressure concentration and separation by chromatographic column to obtain compound 24, colorless oil 600 mg, yield 68.4%. MS (ESI) m / z = 981.5 (M+H+).

[0339] Step 2: Preparation of compound 25

[0340] Under nitrogen protection, compound 24 (600 mg) was dissolved in anhydrous tetrahydrofuran (10 mL), and 1,8-diazobispiro[5.4.0]undec-7-ene (DBU) (100 mg) was added at room temperature and reacted for 2 h. TLC detection showed that no raw material remained, and the reaction was stopped. The reaction solution was directly concentrated to dryness, and then the solvent was removed with dichloromethane and concentrated to dryness to obtain crude compound 25, 420 mg of colorless oil, with a yield of 91.3%. MS (ESI) m / z = 759.4 (M+H+).

[0341] Step 3: Preparation of compound 27

[0342] Under nitrogen protection, compound 25 (400 mg) was dissolved in anhydrous tetrahydrofuran (20 mL), 1-hydroxybenzotriazole (HOBT) (100 mg) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (140 mg) and compound 26 (170 mg, CAS: 2356229-58-6, Shanghai Xiyao Pharmaceutical Technology Co., Ltd.) were added at room temperature, and the reaction was allowed to proceed overnight at room temperature. LC-MS monitored that the reaction of raw material 25 was complete, and after reduced pressure concentration, compound 27 was separated by chromatographic column to obtain 450 mg of colorless oil with a yield of 84.9%. MS (ESI) m / z = 1009.5 (M+H+).

[0343] Step 4: Preparation of compound 28

[0344] Under nitrogen protection, compound 27 (400 mg) was dissolved in dichloromethane (10 mL), trifluoroacetic acid (1.5 mL) was added at room temperature, and the reaction was allowed to proceed overnight at room temperature. LCMS detection showed that no raw material remained, and the reaction was stopped. The reaction solution was directly concentrated to dryness, and then slurried with tert-butyl methyl ether, and filtered under reduced pressure to obtain compound 28 as a light yellow solid of 350 mg, with a yield of 92.8%.

[0345] 1H NMR (400MHz, DMSO) δ9.11(s,2H),8.17(t,J=5.0Hz,1H),8.12(d,J=8.0Hz,1H),8.01(q,J=5.5Hz,1H),7.94(t,J=5.5 Hz,1H),7.27(dd,J=10.0,4.6Hz,2H),7.21(dd,J=11.8,6.3Hz,3H),5.75(s,2H),4.45(ddd,J=13.5,12.6,6.7Hz,2H ),3.72(t,J=6.3Hz,3H),3.64–3.59(m,3H),3.56–3.45(m,30H),3.44–3.39(m,5H),3.22(dd,J=11.5,5.8Hz,2H),3. 10–2.98(m,1H),2.97–2.84(m,1H),2.39(dd,J=13.4,6.9Hz,2H),2.28(t,J=7.3Hz,2H).MS(ESI)m / z=953.4(M+H+).

[0346] Step 5: Preparation of Compound I-4

[0347] Under nitrogen protection, compound 16 (60 mg) was dissolved in anhydrous tetrahydrofuran (10 mL), and 1-hydroxybenzotriazole (HOBT) (17 mg) was added at room temperature to react for 2 h. 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (24 mg) and compound 28 (100 mg) were added at room temperature and reacted overnight at room temperature. LC-MS monitored the complete reaction of compound 16, and after reduced pressure concentration, the compound I-4 was separated by a chromatographic column to obtain a light yellow solid of 30 mg, with a yield of 19.1%.

[0348] 1H NMR (400MHz, DMSO) δ9.64 (s, 1H), 9.12 (s, 2H), 8.61 (t, J = 6.6Hz, 1H), 8.46 (s, 1H) ,8.34(t,J=5.7Hz,1H),8.22–8.11(m,3H),8.10(s,1H),8.02(t,J=5.5Hz,1H),7.9 3(dd,J=12.1,8.0Hz,2H),7.34(s,1H),7.26–7.09(m,5H),6.54(s,1H),5.43(s,2H ),5.29(s,2H),4.63(d,J=6.6Hz,2H),4.47(t,J=10.6Hz,3H),3.90(t,J=5.2Hz,2H ),3.82–3.65(m,5H),3.64–3.54(m,4H),3.52–3.44(m,25H),3.33(s,4H),3.28–3 .16(m,3H),3.02(dd,J=13.7,4.4Hz,1H),2.78(dd,J=13.8,9.8Hz,1H),2.55(t,J= 7.1Hz,2H),2.48(s,3H),2.39(t,J=6.5Hz,2H),2.27(t,J=7.3Hz,2H),1.97–1.75( m, 5H), 1.25 (d, J = 11.0Hz, 1H), 0.89 (t, J = 7.3Hz, 3H). MS (ESI) m / z = 1511.6 (M+H+).

[0349] Example 7: Compounds II-3, II-4

[0350] According to Example 4, Ⅰ-1 was replaced by Ⅰ-3 and Ⅰ-4, respectively, to prepare conjugates II-3, t=7.8; II-4, t=7.7.

[0351]

[0352] Effect Example 1: Effects of Camptothecin Derivatives K1-K9 on Tumor Cell Proliferation

[0353] Camptothecin's ability to test tumor cell proliferation:

[0354] The CTG assay was used to test the effects of camptothecin derivatives K1, K2, K3, K4, K5, K6, K7, K8, and K9 on tumor cell proliferation. After digestion of the test cells (see Table 1), the cells were resuspended for cell counting, the supernatant was removed by centrifugation, and the cell density was adjusted. Counting was performed using a cell counter, 20 μl of the cell suspension was aspirated, mixed with 20 μl of trypan blue, 20 μl of liquid was taken, and the cells were counted. The cells were spread in 96-well cell culture plates, 180 μl was added to each well, and 1000 cells were seeded in each well. Gently tap to mix, and the cell culture plates were placed in a 37°C cell culture incubator for 16 hours. The compound was diluted with McCoy's 5A medium, 20 μl was added to each well, so that the maximum concentration was 100 nM, 3-fold dilution, and 10 points. The vehicle control was DMSO, and 20 μl of McCoy's 5A medium was added to the blank control. Gently tap to mix, and place the cell culture plate in a 37℃ cell culture incubator for 7 days. After 7 days of culture, take the cell plate out of the incubator, remove the culture medium, add 20ul culture medium, and then add 20ul CTG to each well. Oscillate on the oscillator for 5 minutes, let it stand at room temperature for 10 minutes, take 30ul of the reaction solution to the Viewplate-96white white transparent bottom ELISA plate, and perform data analysis on the EnVision plate reader.

[0355] Calculation formula: background value = control group - blank group; inhibition rate = 1 - (experimental group - blank group) / (background value) * 100%.

[0356] Table 1. Overview of cell lines used in this screening

[0357]

[0358]

[0359] Table 2. Effects of compounds on tumor cell proliferation

[0360]

[0361] As shown in Table 2, the compounds of the present invention have better in vitro cell activity.

[0362] Effect Example 2: Effect of Antibody-Antibody Drug Conjugates on Tumor Cell Proliferation Ability

[0363] Test method for the tumor cell proliferation ability of compounds II-1, II-2, II-3 and II-4:

[0364] After digestion of NCI-N87 cells, resuspend the cells for cell counting, centrifuge to remove the supernatant, and adjust the cell density. Count with a cell counter, aspirate 20uL of cell suspension, mix with 20uL VisStain AOPI Staining Solution, take 20uL of liquid, and count the cells. Spread the cells in 96-well cell culture plates, add 180uL to each well, and plant 1000 cells or 2000 cells per well. Gently tap to mix, and place the cell culture plate in a 37°C cell culture incubator for 16 hours. Dilute the compound with RPMI1640medium / 10%FBS, add 20uL to each well, so that the maximum concentration is 100nM, 3-fold dilution, 10 points. The solvent control is DMSO, and 20uL RPMI1640medium / 10%FBS is added to the blank control. Gently tap to mix, and place the cell culture plate in a 37°C cell culture incubator for 7days. After 7 days of culture, the cell plate was taken out of the incubator, the culture medium was removed, 20uL of culture medium was added, and then 20uL of CTG was added to each well. The plate was shaken for 5 minutes, and then allowed to stand at room temperature for 10 minutes. 30uL of the reaction solution was transferred to the Viewplate-96white white transparent bottom ELISA plate, and data was analyzed on the EnVision plate reader.

[0365] Calculation formula: The inhibition rate (IR) of the detection antibody was calculated using the following formula: IR (%) = (1-(antibody-blank control) / (solvent control-blank control))*100%. The inhibition rates of different antibody concentrations were calculated in Excel, and then the relevant parameters were calculated using GraphPad Prism software. The results are shown in Table 3.

[0366] Table 3. Effect of compound NCl-N87 on tumor cell proliferation

[0367] Antibody Drug Conjugates <![CDATA[IC 50 (μg / mL)]]> II-1 0.0115 II-2 0.0187 II-3 0.0261 II-4 0.0238 .

[0368] Effect Example 3: Bystander Effects of Antibody Drug Conjugate II-2 and T-Dxd on NCI-N87 and MDA-MB-231 Cells

[0369] In this experiment, II-2 and T-Dxd were co-cultured with NCI-N87 / MDA-MB-231 cells for 7 days, and flow cytometry was used to detect the proportion of NCI-N87 or MDA-MB-231 cells in the total number of particles to reflect the ability of ADC to kill negative cells through the bystander effect.

[0370] NCI-N87 cells were cultured in a T175 culture flask. After digestion, 8 ml of cells were resuspended and counted. The supernatant was removed by centrifugation to adjust the cell density. MDA-MB-231 (ATCC, HTB-26) cells were cultured in a T175 culture flask. After digestion, 6 ml of cells were resuspended and counted. The supernatant was removed by centrifugation to adjust the cell density. Count with a cell counter, aspirate 20 μl of cell suspension, mix with 20 μl VisStain AOPI Staining Solution, take 20 μl of liquid, and count the cells. Use RPMI1640 medium / 10% FBS to spread cells in 96-well cell culture plates (flat bottom), and add 90 ul to each well for each cell, that is, the ratio of NCI-N87 10000 cell / well + MDA-MB-231 2000 cell / well (5:1) cells per well. Gently tap to mix, and place the cell culture plate in a 37°C 5% CO2 cell culture incubator for 16 hours. Antibody dilution: First dilute the antibody to 10ug / ml stock solution with RPMI1640 medium / 10% FBS, add 20ul to each well, and add 20μl RPMI1640 medium / 10% FBS to the blank control. Gently tap to mix, and place the cell culture plate in a 37℃ 5% CO2 cell culture incubator for 7days. After 7 days of culture, remove the cell plate from the incubator, aspirate the culture medium, add 100ul trypsin, and incubate in a 37℃ cell culture incubator for 15 minutes. Add 100ul RPMI1640 medium / 10% FBS, blow the cells to separate from the bottom of the well, and transfer to a 96-well cell culture plate (V bottom). Centrifuge at 350g for 5 minutes and remove the supernatant. Prepare Trastuzumab with PBS containing 2% FBS to a concentration of 1ug / ml, add 100ul to each tube, and incubate at 4 degrees for 1 hour. Centrifuge at 350g for 5 minutes and remove the supernatant. Dilute the secondary antibody PE labeled-human IgG with 2% FBS in PBS at 1:2000, add 100ul to each well, and incubate at 4 degrees for 0.5 hours. Centrifuge at 350g for 5 minutes, remove the supernatant, and resuspend with 100ul PBS containing 2% FBS to prepare for analysis. The results are shown in Table 4 below.

[0371] Calculation formula: negative cell percentage = number of negative cell particles / total number of cell particles*100%, positive cell percentage = number of positive cell particles / total number of cell particles*100%.

[0372] Table 4

[0373]

[0374] As can be seen from the above table, compared with the negative control antibody, compounds II-1 and T-Dxd caused a significant decrease in the number of cells in both positive and negative cell populations (NCI-N87 and MDA-MB-231 cells, respectively), and the effect of II-1 was better than that of T-Dxd.

[0375] Effect Example 4. Antitumor efficacy test of II-1 and II-2 on the NOG mouse subcutaneous transplantation NCI-N87 cell animal model

[0376] In this study, NCI-N87 cells were subcutaneously inoculated into NOG mice to determine the anti-tumor effects of Ⅱ-1 and Ⅱ-2.

[0377] NOG mice: Female NOG mice (6 weeks old) were purchased from Beijing Weitonglihua Experimental Animal Technology Co., Ltd. The mice were adaptively housed for 7 days after arrival, and then the study began.

[0378] Cells: Human gastric cancer NCI-N87 cells (ATCC source, catalog number CRL-5822) were routinely subcultured according to the instructions; cells were resuspended in serum-free medium and the cell density was adjusted. On day 0, the cell suspension (inoculation volume was 1×10 7 ) were subcutaneously inoculated into the right axilla of female NOG mice to establish the NCI-N87 tumor-bearing mouse model.

[0379] Dosage:

[0380] On the 10th day after tumor cell inoculation, the tumor volume of each mouse was measured, and mice with a tumor volume of 110 mm 3 ~250mm 3 Mice within the range were grouped according to tumor volume (5 mice per group) and were given drugs on the 11th day after inoculation, negative control antibody (human IgG Control, source: Hangzhou Haoyang Biotechnology Co., Ltd., catalog number: HSP067-F1), positive control antibody Trastuzumab (HER2 antibody, CAS: 180288-69-1, purchased from Hangzhou Haoyang Biotechnology Co., Ltd.), II-1 and II-2. The tumor volume and body weight changes of mice in each group were monitored during the drug administration period. The monitoring frequency was 2 times / week for 3 consecutive weeks. The body weight and tumor volume were measured before each drug administration. The tumor volume inhibition rate (TGI%) was calculated on the 23rd day after drug administration. The calculation formula is as follows: TGI (%) = [1-(Ti-T0) / (Vi-V0)] × 100; where Ti: mean tumor volume of the drug administration group, T0: mean tumor volume of the drug administration group on D0 day, Vi: mean tumor volume of the isotype control group, V0: mean tumor volume of the isotype control group on D0 day. Tumor volume measurement: The long diameter (a) and wide diameter (b) of the tumor were measured using a vernier caliper, and the tumor volume was calculated using the following formula: TV = 1 / 2 × a × b 2 Body weight was measured using an electronic balance.

[0381] The dosage and method of administration are shown in Table 5 below.

[0382] Table 5. Drug administration study design

[0383] serial number Dosage Dosing frequency Dosage Negative control antibody 4mg / kg Single dose Intravenous injection Positive control antibody 4mg / kg Single dose Intravenous injection Ⅱ-1 4mg / kg Single dose Intravenous injection Ⅱ-2 4mg / kg Single dose Intravenous injection

[0384] As shown in Table 6 and Figure 1 As shown, on the 23rd day after administration, II-1 and II-2 at a dose of 4 mg / kg significantly inhibited tumor growth, with tumor volume inhibition rates of 116.3% and 115.9%, respectively.

[0385] Table 6. Antibody-drug conjugates' ability to inhibit tumor growth in vivo on day 23

[0386]

[0387] Note: P value is compared with negative control antibody

[0388] The above experiments showed that Ⅱ-1 and Ⅱ-2 significantly inhibited tumor growth and had no significant effect on the body weight of NOG mice ( Figure 2 ).

[0389] Effect Example 5. Antitumor efficacy test of II-1 and II-2 on the NOG mouse subcutaneous transplantation JIMT-1 cell animal model

[0390] In this study, JIMT-1 cells were subcutaneously inoculated into NOG mice to determine the anti-tumor effects of Ⅱ-1 and Ⅱ-2.

[0391] NOG mice: Female NOG mice (6 weeks old) were purchased from Beijing Weitonglihua Experimental Animal Technology Co., Ltd. The mice were adaptively housed for 7 days after arrival, and then the study began.

[0392] Cells: Human breast cancer JIMT-1 cells (Shanghai Yubo Biotechnology, catalog number YBC71) were routinely subcultured according to the instructions; cells were resuspended in serum-free medium and the cell density was adjusted. On day 0, the cell suspension (inoculation volume was 3×10 6 ) were subcutaneously inoculated into the right axilla of female NOG mice to establish a JIMT-1 tumor-bearing mouse model.

[0393] Dosage:

[0394] On the 10th day after tumor cell inoculation, the tumor volume of each mouse was measured, and mice with a tumor volume of 110 mm 3 ~250mm 3Mice within the range were grouped according to tumor volume (5 mice per group), and were given drugs once on the 11th and 18th days after inoculation, respectively, negative control antibodies (human IgG Control, source: Hangzhou Haoyang Biotechnology Co., Ltd., catalog number: HSP067-F1), Ⅱ-1 and Ⅱ-2. The tumor volume and body weight changes of mice in each group were monitored during the drug administration period. The monitoring frequency was 2 times / week, and the monitoring was continued for 4 weeks. The body weight and tumor volume were measured before each drug administration, and the tumor volume inhibition rate (TGI%) was calculated on the 28th day after drug administration. The calculation formula is as follows: TGI (%) = [1-(Ti-T0) / (Vi-V0)] × 100; where Ti: mean tumor volume of the drug administration group, T0: mean tumor volume of the drug administration group on D0 day, Vi: mean tumor volume of the same type control group, V0: mean tumor volume of the same type control group on D0 day. Tumor volume measurement: The long diameter (a) and wide diameter (b) of the tumor were measured with a vernier caliper, and the tumor volume was calculated according to the following formula: TV = 1 / 2 × a × b 2 Body weight was measured using an electronic balance.

[0395] The dosage and method of administration are shown in Table 7.

[0396] Table 7. Drug administration study design

[0397]

[0398] As shown in Table 8 and Figure 3 As shown, on the 28th day after administration, II-1 and II-2 at a dose of 6 mg / kg significantly inhibited tumor growth, with tumor volume inhibition rates of 122.4% and 120.9%, respectively.

[0399] Table 8. Ability of ADC to inhibit tumor growth in vivo

[0400]

[0401]

[0402] Note: P value is compared with negative control antibody

[0403] The above experiments showed that Ⅱ-1 and Ⅱ-2 significantly inhibited the growth of tumors in the NOG mouse subcutaneously transplanted JIMT-1 cell animal model, and had no significant effect on the body weight of NOG mice ( Figure 4 ).

Claims

1. A camptothecin compound or a pharmaceutically acceptable salt thereof as shown in formula K: in, R 1 C 1-6 alkyl; R 2 is a halogen; A is CH or N; n is 0, 1, 2 or 3.

2. The camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: It meets one or more of the following conditions: (1)R 1 In the C 1-6 Alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl; for example, methyl; (2)R 2 wherein the halogen is fluorine, chlorine, bromine or iodine; for example, fluorine; (3) for 3. The camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: It meets one or more of the following conditions: (1)R 1 is methyl, R 2 is fluorine, chlorine, bromine or iodine, for example fluorine; (2) n is 0, 1 or 2, preferably, for 4. The camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: The camptothecin compound represented by formula K is a compound represented by formula K-1 or a compound represented by formula K-2; Wherein, A and n are each independently as described in any one of claims 1 to 3.

5. The camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: The camptothecin compound shown in formula K is any of the following structures:

6. A linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof; in, Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, a tetrapeptide residue or a pentapeptide residue; X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -、-(OCH2CH2) m -、-(CR a R b ) m -、-O(CR a R b ) m -、-NH-(CR a R b ) m -CR c R d - or -S(CR a R b ) m -CR c R d -; R a and R b are independently H, D, halogen, C 1-6 Alkyl, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, C 1-6 Alkoxy, hydroxy, amino, cyano, nitro, 3-10 membered cycloalkyl or 3-10 membered heterocyclic group; Or, R a and R b Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group; R c and R d Independently H, C 1-6 Alkyl, halogen, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, 3-10 membered cycloalkyl, 3-10 membered heterocyclyl, 6-14 membered aryl or 5-10 membered heteroaryl; Or, R c and R d Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group; The heteroatoms in each 3-10 membered heterocyclyl and 5-10 membered heteroaryl are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3; Y is R 4 C 1-6 Alkyl or one or more C 1-6 Alkyl substituted phenyl; m, p, q and r are independently integers from 0 to 14; R 1 , R 2 , A and n are as defined in any one of claims 1-5.

7. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 6, characterized in that: It is any of the following options: Solution 1: Q is a single amino acid residue, a dipeptide residue, a tripeptide residue or a tetrapeptide residue; X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -、-(OCH2CH2) m -、-(CR a R b ) m -、-O(CR a R b ) m -、-NH-(CR a R b ) m -CR c R d - or -S(CR a R b ) m -CR c R d -; R a and R b are independently H, D, halogen, C 1-6 Alkyl, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, C 1-6 Alkoxy, hydroxy, amino, cyano, nitro, 3-10 membered cycloalkyl or 3-10 membered heterocyclic group; Or, R a and R b Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group; R c and R d Independently H, C 1-6 Alkyl, halogen, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, 3-10 membered cycloalkyl, 3-10 membered heterocyclyl, 6-14 membered aryl or 5-10 membered heteroaryl; Or, R c and R d Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group; The heteroatoms in each 3-10 membered heterocyclyl and 5-10 membered heteroaryl are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3; Y is m, p, q and r are independently integers from 0 to 14; R 1 , R 2 , A and n are defined as in claim 6; Option 2: Q is a tetrapeptide residue; X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CR a R b ) m -*, wherein the -* end is connected to the carbonyl group; R a and R b is H; Y is R 4 C 1-6 alkyl; m is 5; P is 8; q and r are independently 2 or 3; R 1 , R 2 , A and n are defined as in claim 6; Option 3: Q is a tetrapeptide residue; X is -(CR a R b ) m -; R a and R b independently H; Y is m is 5; for R 1 , R 2 , A and n are defined as in claim 6; Option 4: R 1 C 1-6 alkyl; R 2 is a halogen; A is CH or N; n is 0, 1, 2 or 3; for Q is a single amino acid residue, a dipeptide residue, a tripeptide residue or a tetrapeptide residue; X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CR a R b ) m -*, wherein the -* terminal group is attached to a carbonyl group; R a and R b is H; Y is R 4 C 1-6 alkyl; m is an integer from 0 to 8; p is an integer from 0 to 10; q and r are independently integers from 0 to 8; Option 5: Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, a tetrapeptide residue or a pentapeptide residue; X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -*,*-(OCH2CH2) m -、-(CR a R b ) m -、*-O(CR a R b ) m -、*-NH-(CR a R b ) m -CR c R d -or*-S(CR a R b ) m -CR c R d -, where the * end is connected to the carbonyl group; R a and R b are independently H, D, halogen, C 1-6 Alkyl, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, C 1-6 Alkoxy, hydroxy, amino, cyano, nitro, 3-10 membered cycloalkyl or 3-10 membered heterocyclic group; Or, R a and R b Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group; R c and R d Independently H, C 1-6 Alkyl, halogen, halogenated C 1-6 Alkyl, deuterated C 1-6 Alkyl, 3-10 membered cycloalkyl, 3-10 membered heterocyclyl, 6-14 membered aryl or 5-10 membered heteroaryl; Or, R c and R d Together with the carbon atom to which it is attached, it forms a 3-10 membered cycloalkyl group or a 3-10 membered heterocyclic group; The heteroatoms in each 3-10 membered heterocyclyl and 5-10 membered heteroaryl are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3; Y is R 4 C 1-6 Alkyl or one or more C 1-6 Alkyl substituted phenyl; m, p, q and r are independently integers from 0 to 14; R 1 , R 2 , A and n are defined as in claim 6.

8. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 6 or 7, characterized in that: It meets one or more of the following conditions: (1) Each halogen is independently fluorine, chlorine, bromine or iodine; (2) Each C 1-6 Alkyl is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl; (3) Each C 1-6 Alkoxy is independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy; (4) each 3-10 membered cycloalkyl group is independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl; (5) Each 3-10 membered heterocyclic group is independently a 3-6 membered heterocyclic group, the heteroatoms of the 3-6 membered heterocyclic group are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3; (6) Each 6-14 membered aryl group is independently phenyl or naphthyl; (7) each 5-10 membered heteroaryl group is independently a 5-6 membered heteroaryl group, the heteroatoms of the 5-6 membered heteroaryl group are independently selected from one, two or three of N, O or S, and the number of heteroatoms is independently 1, 2 or 3; (8) In Q, the single amino acid residue is -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Ile-, -Arg-, -Trp- or -Gly-; (9) In Q, the dipeptide residue is C＝O -Lys-Phe- NH , C＝O -Ala-Val- NH , C＝O -Lys-Val- NH , C＝O -Lys-Ala- NH , C＝O -Cit-Val- NH , C＝O Cit-Phe- NH , C＝O -Cit-Leu- NH , C＝O Cit-Ile- NH , C＝O -Arg-Phe- NH , C＝O -Cit-Trp- NH or C＝O -Val-Gly- NH ;For example C＝O -Ala-Val- NH ; (10) In Q, the tripeptide residue is C＝O -Ala-Val-Glu- NH , C＝O -Cit-Val-Glu- NH , C＝O -Ala-Val-αGlu- NH or C＝O -Cit-Val-αGlu- NH ;and (11) In Q, the tetrapeptide residue is C＝O -Gly-Phe-(Gly)2- NH or C＝O -(Gly)2-Phe-Gly- NH ,For example C＝O -Gly-Phe-(Gly)2- NH .

9. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 6 or 7, characterized in that: It meets one or more of the following conditions: (1) The amino acid residues are independently -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Glu-, -Ile-, -Arg-, -Trp- or -Gly-; (2) Q is a tetrapeptide residue; preferably, the tetrapeptide residue is in Connected to -NH- group; (3)X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -*,*-(OCH2CH2) m -、-(CR a R b ) m -、*-O(CR a R b ) m -、*-NH-(CR a R b ) m -CR c R d -or*-S(CR a R b ) m -CR c R d -, where the * end is connected to the carbonyl group; Preferably, X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CR a R b ) m -, for example, X is -(CR a R b ) m -, wherein the -* end is connected to the carbonyl group; (4) m is an integer from 0 to 8, such as 5, 6, 7 or 8; (5) p is an integer from 0 to 10, such as 5, 6, 7 or 8; (6) q and r are independently integers from 0 to 8; (4)Y is in The end is connected to X; preferably, Y is in The end is connected to X; (6) for 10. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 6 or 7, characterized in that: It meets one or more of the following conditions: (1)R a and R b is H; (2) m is 1, 2, 3, 4 or 5; (3) p is 8, 9, 10, 11, 12, 13 or 14; (4) q is 1, 2, 3, 4 or 5; (5) r is 1, 2, 3, 4 or 5; (6) Q is a dipeptide residue or a tetrapeptide residue; for example C＝O -Ala-Val- NH or C＝O -Gly-Phe-(Gly)2- NH ;and (7)X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -or-(CR a R b ) m -;For example Another example The "1" bit is connected to Y, and the "2" bit is connected to connect.

11. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 10, characterized in that: It meets one or more of the following conditions: (1)R a and R b independently H; (2) m is 5; (3) p is 8; (4)q is 2; (5) r is 2; (6)n is 0 or 1; (7) The single amino acid residue is -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Ile-, -Arg- or -Trp-; (8) The dipeptide residue is C＝O -Lys-Phe- NH , C＝O -Ala-Val- NH , C＝O -Lys-Val- NH , C＝O -Lys-Ala- NH , C＝O -Cit-Val- NH , C＝O Cit-Phe- NH , C＝O -Cit-Leu- NH , C＝O Cit-Ile- NH , C＝O -Arg-Phe- NH , C＝O -Cit-Trp- NH or C＝O -Val-Gly- NH ; (9) The tripeptide residue is C＝O -Ala-Val-Glu- NH , C＝O -Cit-Val-Glu- NH , C＝O -Ala-Val-αGlu- NH or C＝O -Cit-Val-αGlu- NH ; (10) The tetrapeptide residue is C＝O -Gly-Phe-(Gly)2- NH or C＝O -(Gly)2-Phe-Gly- NH .

12. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 6 or 7, characterized in that: It meets one or more of the following conditions: (1) for (2) for (3) for in The end is connected to -O-.

13. The linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof according to claim 6 or 7, characterized in that: The linker-drug conjugate as shown in Formula I is any of the following structures:

14. An antibody-drug conjugate of formula II or a pharmaceutically acceptable salt thereof; in, G L For antibodies; t is the drug-ligand coupling ratio; Z is The b end is connected to X, and the a end is connected to G L connect; R 1 , R 2 , A and n are defined as in any one of claims 1 to 5; Q and X are as defined in any one of claims 6-13.

15. The antibody-drug conjugate of formula II or a pharmaceutically acceptable salt thereof according to claim 14, characterized in that: It is any of the following options: Solution 1: G L For antibodies; t is the drug-ligand coupling ratio; Z is The b end is connected to X, and the a end is connected to G L connect; R 1 , R 2 , A and n are defined as in any one of claims 1 to 5; Q and X are defined as in any one of claims 6 to 13; Option 2: G L For antibodies; t is a natural number or decimal from 1 to 8; Z is The b end is connected to X, and the a end is connected to G L connect; R 1 , R 2 , A and n are defined as in any one of claims 1 to 5; Q and X are as defined in any one of claims 6-13.

16. The antibody-drug conjugate of formula II or a pharmaceutically acceptable salt thereof according to claim 14 or 15, characterized in that: It meets one or more of the following conditions: (1) G L Anti-HER2 antibodies, such as trastuzumab; (2) t is a natural number and / or decimal of 1-8; for example, a natural number and / or decimal of 7-8; for example, 7.8; or t is a natural number of 1-8; for example, t is a natural number of 7-8, preferably 7, 7.7 or 7.8; (3) the a-end of the Z and the G L Connected by thioether bonds.

17. The antibody-drug conjugate of formula II or a pharmaceutically acceptable salt thereof according to claim 14, characterized in that: The antibody-drug conjugate shown in Formula II is any of the following structures: The HER2 antibody is trastuzumab; t is the drug-ligand coupling ratio; Preferably, the antibody-drug conjugate as shown in Formula II is any of the following structures: The anti-HER2 antibody is trastuzumab.

18. A pharmaceutical composition comprising a camptothecin compound as shown in formula K as described in any one of claims 1 to 5 or a pharmaceutically acceptable salt thereof, a linker-drug conjugate as shown in formula I as described in any one of claims 6 to 13 or a pharmaceutically acceptable salt thereof, or an antibody-drug conjugate as shown in formula II as described in any one of claims 14 to 17 or a pharmaceutically acceptable salt thereof.

19. Use of a camptothecin compound of formula K or a pharmaceutically acceptable salt thereof as described in any one of claims 1 to 5, a linker-drug conjugate of formula I or a pharmaceutically acceptable salt thereof as described in any one of claims 6 to 13, an antibody-drug conjugate of formula II or a pharmaceutically acceptable salt thereof as described in any one of claims 14 to 17, or a pharmaceutical composition as described in claim 18 in the preparation of a drug for preventing and / or treating cancer; The cancer is preferably breast cancer, lung cancer, kidney cancer, liver cancer, ovarian cancer, urethral cancer, prostate cancer, glioblastoma multiforme, pancreatic cancer, colorectal cancer, gastrointestinal stromal tumor, cervical cancer, squamous cell carcinoma, peritoneal cancer, colon cancer, rectal cancer, uterine cancer, salivary gland cancer, kidney cancer, vulvar cancer, thyroid cancer, penile cancer, leukemia, malignant lymphoma, plasmacytoma, myeloma, sarcoma, melanoma, bladder cancer, gastric cancer or esophageal cancer, preferably breast cancer or preferably lung adenocarcinoma, gastric cancer or colon cancer, and the lung cancer may be lung adenocarcinoma, such as gastric cancer, lung cancer, colon cancer or breast cancer.

20. A method for preparing the camptothecin compound of formula K as described in any one of claims 1 to 5, the antibody drug conjugate of formula II as described in any one of claims 14 to 17, or a pharmaceutically acceptable salt thereof, which is any of the following schemes: Solution 1: Scheme 1 comprises the following steps: coupling a linker-drug conjugate as shown in Formula I with an antibody to obtain an antibody-drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof; in, R 1 , R 2 ,A,n, Q, X, R a , R b , Z, G L , t, m, p, q and r are independently as described in any one of claims 1-17: Option 2: Scheme 2 comprises the following steps: in a halogenated alkane solvent, under the action of a catalyst, a compound represented by formula Ka and an azide compound represented by formula Kb are subjected to a cyclization reaction to obtain a camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof; Where A is N; R 1 , R 2 and n as described in any one of claims 1 to 5; Option 3: Scheme 3 comprises the following steps: in an aromatic hydrocarbon solvent, in the presence of an organic acid, subjecting a compound represented by formula Kc and a compound represented by formula Kd to a cyclization reaction to obtain a camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof; Wherein, A is CH; R 1 , R 2 and n as described in any one of claims 1-5.

21. A compound or a pharmaceutically acceptable salt thereof, characterized in that: The compound is a compound represented by formula Ka or a compound represented by formula Kc; Wherein, A is CH; R 1 , n and R 2 As claimed in claim 20; Preferably, the compound as shown in formula Ka is Preferably, the compound represented by formula Kc is any of the following compounds:

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