Camptothecin compound, antibody drug conjugate, and preparation method therefor and use thereof

Abstract

Provided are a camptothecin compound, an antibody drug conjugate, and a preparation method therefor and the use thereof. Specifically provided is a camptothecin compound as represented by formula (K) or a pharmaceutically acceptable salt thereof. The provided camptothecin compound and the antibody drug conjugate thereof have a good cytotoxic activity and can inhibit the proliferation of tumor cells.

Description

Camptothecin compound, antibody-drug conjugate, and preparation method and application thereof

[0001] This application claims the benefit of Chinese Patent Application No. 2023109020423 filed on July 20, 2023, and Chinese Patent Application No. 2023116319073 filed on November 30, 2023. The entire contents of the aforementioned Chinese patent applications are incorporated herein by reference. 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 an important family of traditional anti-tumor drugs, attracting widespread attention due to their unique mechanism of action (selective inhibition of DNA topoisomerase I). Currently, three CPT derivatives have been approved for marketing for cancer treatment (irinotecan, topotecan, and belotecan). In addition, many other CPT derivatives, such as Gimatecan, Karenitecin, Rubitecan, Silatecan, Exatecan, Lurtotecan, and Simmitecan, are in various stages of clinical trials.

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

[0005] Summary of the Invention

[0006] 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 excellent cytotoxic activity and can inhibit the proliferation of tumor cells.

[0007] The present invention solves the above technical problems through the following solutions.

[0008] The present invention provides a camptothecin compound represented by formula K or a pharmaceutically acceptable salt thereof:

[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 one embodiment, the camptothecin compound represented by Formula K or a pharmaceutically acceptable salt thereof 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] In one embodiment, n is 0, 1 or 2.

[0020] 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;

[0021] Wherein, A and n are independently as described in any embodiment of the present invention.

[0022] In one embodiment, the camptothecin compound represented by Formula K or a pharmaceutically acceptable salt thereof is selected from any one of the following structures:

[0023] The present invention also provides a linker-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula I:

[0024] wherein Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, a tetrapeptide residue or a pentapeptide residue;

[0025] 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 -;

[0026] 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;

[0027] 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;

[0028] 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;

[0029] Or, Rc 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;

[0030] 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;

[0031] Y is

[0032] R 4 C 1-6 Alkyl or one or more C 1-6 Alkyl-substituted phenyl groups;

[0033] m, p, q and r are independently integers from 0 to 14;

[0034] R 1 、R 2 , A and n are defined as described in any embodiment of the present invention.

[0035] 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 ( carbonyl) connection.

[0036] In one embodiment, in the linker-drug conjugate shown in Formula I or a pharmaceutically acceptable salt thereof,

[0037] Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, a tetrapeptide residue or a pentapeptide residue;

[0038] 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 (-* or *-) and the carbonyl ( carbonyl) connection;

[0039] 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;

[0040] 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;

[0041] 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;

[0042] 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;

[0043] 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;

[0044] Y is

[0045] R 4 C 1-6Alkyl or one or more C 1-6 Alkyl-substituted phenyl groups;

[0046] m, p1, q1, r1, p, q and r are independently integers from 0 to 14;

[0047] R 1 、R 2 , A and n are defined as described in any embodiment of the present invention.

[0048] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof is:

[0049] wherein Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, or a tetrapeptide residue;

[0050] 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 -;

[0051] 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;

[0052] 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;

[0053] 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;

[0054] 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;

[0055] 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;

[0056] Y is

[0057] m, p, q and r are independently integers from 0 to 14;

[0058] R 1 、R 2 , A and n are defined as described in any embodiment of the present invention.

[0059] 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-.

[0060] 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-.

[0061] In one embodiment, the tripeptide residue is -Ala-Val-Glu-, -Cit-Val-Glu-, -Ala-Val-αGlu- or -Cit-Val-αGlu-.

[0062] 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.

[0063] In one scenario, R a 、R b 、R c and R d wherein the halogen is independently fluorine, chlorine, bromine or iodine.

[0064] 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 Alkyl is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.

[0065] In one scenario, R a 、R b 、R c and R d wherein the halogenated C 1-6 Alkyl is independently C substituted by 1, 2 or 3 halogens. 1-6 The halogen is preferably independently fluorine, chlorine, bromine or iodine.

[0066] 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.

[0067] 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.

[0068] In one scenario, R a 、R b 、R c and R d In the above, the 3-10 membered heterocyclic group is independently a 3-6 membered heterocyclic group, 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.

[0069] In one scenario, Ra 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.

[0070] 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.

[0071] In one scenario, R c and R d wherein the 6-14 membered aryl groups are independently phenyl or naphthyl.

[0072] 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, 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.

[0073] 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.

[0074] 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 aR b ) m -CR c R d -, where the * terminal (*- or -*) group and the carbonyl ( carbonyl) connection.

[0075] In one scenario, Y is in Connect the X end.

[0076] In one embodiment, the linker-drug conjugate of Formula I or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0077] (1) Each halogen is independently fluorine, chlorine, bromine or iodine;

[0078] (2) Each C 1-6 Alkyl is independently methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl;

[0079] (3) Each C 1-6 Alkoxy is independently methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy;

[0080] (4) Each 3-10 membered cycloalkyl group is independently cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl;

[0081] (5) Each 3-10 membered heterocyclic group is independently a 3-6 membered heterocyclic group, wherein 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;

[0082] (6) Each 6-14 membered aryl group is independently phenyl or naphthyl;

[0083] (7) Each 5-10 membered heteroaryl group is independently a 5-6 membered heteroaryl group, wherein 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;

[0084] (8) In Q, the single amino acid residue is -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Ile-, -Arg-, -Trp-, or -Gly-;

[0085] (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 ;

[0086] (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

[0087] (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 .

[0088] In one embodiment, the linker-drug conjugate of Formula I or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0089] (1)R a and R b is H;

[0090] (2) m is 1, 2, 3, 4 or 5;

[0091] (3) p is 8, 9, 10, 11, 12, 13 or 14;

[0092] (4) q is 1, 2, 3, 4 or 5;

[0093] (5) r is 1, 2, 3, 4 or 5;

[0094] (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

[0095] (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 For example The "1" bit is connected to Y, and the "2" bit is connected to connect.

[0096] In one embodiment, the linker-drug conjugate of Formula I or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0097] (1)R a and R b independently H;

[0098] (2) m is 5;

[0099] (3) p is 8;

[0100] (4)q is 2;

[0101] (5) r is 2;

[0102] (6) n is 0 or 1;

[0103] (7) The single amino acid residue is -Phe-, -Lys-, -Val-, -Ala-, -Cit-, -Leu-, -Ile-, -Arg- or -Trp-;

[0104] (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 ;

[0105] (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 ;

[0106] (10) The tetrapeptide residue is C＝O -Gly-Phe-(Gly)2- NH or C＝O -(Gly)2-Phe-Gly- NH .

[0107] 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 end connected to the carbonyl group).

[0108] In one embodiment, X is -(CR a R b ) r -CO-NH-(CR a R b ) q -(OCH2CH2) p -* or -(CR a R b ) m -, preferably, X is -(CR a R b ) m -, where -* ends with carbonyl ( carbonyl) connection.

[0109] In one scheme, R a and R b For H.

[0110] In one embodiment, m is an integer from 0 to 8, such as 5, 6, 7 or 8, preferably 5.

[0111] In one embodiment, p is an integer from 0 to 10, such as 5, 6, 7 or 8, preferably 8.

[0112] In one embodiment, q and r are independently an integer from 0 to 8, such as 2 or 3.

[0113] In one solution, Y is in Connect the X end.

[0114] In one plan, for

[0115] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof;

[0116] Wherein, Q is a tetrapeptide residue;

[0117] 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;

[0118] R a and R b is H;

[0119] Y is

[0120] R 4 C 1-6 alkyl;

[0121] m is 5;

[0122] P is 8;

[0123] q and r are independently 2 or 3;

[0124] R 1 、R2 , A and n are defined as described in any embodiment of the present invention.

[0125] In one embodiment, the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof;

[0126] Wherein, Q is a tetrapeptide residue;

[0127] X is -(CR a R b ) m -;

[0128] R a and R b independently H;

[0129] Y is

[0130] m is 5;

[0131] for

[0132] R 1 、R 2 , A and n are defined as described in any embodiment of the present invention.

[0133] In one embodiment, in the linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof,

[0134] R 1 C 1-6 alkyl;

[0135] R 2 is a halogen;

[0136] A is CH or N;

[0137] n is 0, 1, 2, or 3;

[0138] for

[0139] Q is a single amino acid residue, a dipeptide residue, a tripeptide residue, or a tetrapeptide residue;

[0140] 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;

[0141] R a and R b is H;

[0142] Y is

[0143] R 4 C 1-6 alkyl;

[0144] m is an integer from 0 to 8;

[0145] p is an integer from 0 to 10;

[0146] q and r are independently integers from 0 to 8.

[0147] In one plan, for

[0148] In one plan, for

[0149] In one plan, for in The end is connected to -O-.

[0150] 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:

[0151] The present invention also provides an antibody-drug conjugate or a pharmaceutically acceptable salt thereof as shown in Formula II:

[0152] Among them, G L For antibodies;

[0153] t is the drug-ligand coupling ratio;

[0154] 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 as defined in any embodiment of the present invention;

[0155] The definitions of Q and X are as described in any embodiment of the present invention.

[0156] In one scheme, GL is an anti-HER2 antibody, such as trastuzumab, preferably the G L It is connected to Z via a thioether (-S-) bond.

[0157] In the antibody drug conjugate of Formula II or a pharmaceutically acceptable salt thereof, 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.

[0158] In one embodiment, the antibody-drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof is:

[0159] Among them, G L For antibodies;

[0160] t is the drug-ligand coupling ratio;

[0161] Z is The b end is connected to X, and the a end is connected to G L connect;

[0162] R 1 、R 2 , A and n are as defined in any embodiment of the present invention;

[0163] The definitions of Q and X are as described in any embodiment of the present invention.

[0164] In one embodiment, the antibody drug conjugate of Formula II or a pharmaceutically acceptable salt thereof satisfies one or more of the following conditions:

[0165] (1)G L Anti-HER2 antibodies, such as trastuzumab;

[0166] (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

[0167] (3) the a end of the Z and the G L Connected by thioether bonds.

[0168] In a certain embodiment, in the antibody-drug conjugate of Formula II or a pharmaceutically acceptable salt thereof,

[0169] Z is The b end is connected to X, and the a end is connected to G L connect;

[0170] G L is an antibody (e.g., an anti-HER2 antibody);

[0171] t is 1-8;

[0172] R 1 、R 2 、A、n、 Q and X are as described in any embodiment of the present invention.

[0173] In one 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:

[0174] The HER2 antibody is trastuzumab.

[0175] In one embodiment, the antibody drug conjugate shown in Formula II is any of the following structures:

[0176] The anti-HER2 antibody is trastuzumab.

[0177] The present invention provides a method for preparing an antibody-drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof, comprising the following steps: subjecting a linker-drug conjugate as shown in Formula I or a pharmaceutically acceptable salt thereof to a coupling reaction with an antibody to obtain an antibody-drug conjugate as shown in Formula II or a pharmaceutically acceptable salt thereof;

[0178] 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.

[0179] The present invention provides a method for preparing the camptothecin compound represented by Formula K or a pharmaceutically acceptable salt thereof, which is Scheme 1 or Scheme 2;

[0180] Scheme 1 comprises the following steps: a compound represented by Formula Ka and an azide compound represented by Formula Kb are subjected to a cyclization reaction in a halogenated alkane solvent (e.g., dichloromethane) in the presence of a catalyst (e.g., copper tetraacetonitrile hexafluorophosphate) to obtain a compound represented by Formula K;

[0181] Where A is N;

[0182] R 1 、R 2 and n is as described in any embodiment of the present invention;

[0183] Scheme 2 comprises the following steps: cyclizing a compound represented by Formula Kc and a compound represented by Formula Kd in an aromatic hydrocarbon solvent (such as toluene) in the presence of an organic acid (such as acetic acid) to obtain a compound represented by Formula K;

[0184] Wherein, A is CH;

[0185] R 1 、R 2 and n are as described in any embodiment of the present invention.

[0186] The present invention also provides a compound as shown in formula Ka or a pharmaceutically acceptable salt thereof;

[0187] Among them, R 1 、R 2 As described in any embodiment of the present invention.

[0188] Preferably, the compound represented by formula Ka is

[0189] The present invention also provides a compound represented by formula Kc or a pharmaceutically acceptable salt thereof;

[0190] Among them, A is CH, R 1 、R 2 and n are as described in any embodiment of the present invention.

[0191] Preferably, the compound represented by formula Kc is any one of the following compounds:

[0192] 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.

[0193] 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 combination as described in any embodiment of the present invention (in a therapeutically effective amount) in the preparation of a drug for preventing and / or treating cancer.

[0194] 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 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, plasma cell tumor, 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.

[0195] Definition of terms

[0196] Stereochemical definitions and conventions used herein 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.

[0197] Depending on the choice of starting materials and process, the compounds of the present invention may exist as one of the possible isomers or as 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.

[0198] Any resulting mixture of stereoisomers can be separated into the pure or substantially pure geometric isomers, enantiomers, and diastereomers on the basis of the differences in the constituent physicochemical properties, for example, by chromatography and / or fractional crystallization.

[0199] 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.

[0200] 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.

[0201] In the present invention, a substituent 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.

[0202] The term "halogen" refers to fluorine, chlorine, bromine or iodine.

[0203] 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, and n-octyl.

[0204] In this application, the term "alkoxy" as a group or part of another group refers to -O-alkyl, and alkyl is as defined above.

[0205] The term "cycloalkyl" refers to a cycloalkyl group having the specified number of carbon atoms (e.g., C 3-6 、C 3-10 ) is a saturated monocyclic ring group consisting only of carbon atoms. Cycloalkyl includes but is not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0206] 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), and a specified type of heteroatom (one or more of N, O, and S), which is monocyclic, bridged, or spirocyclic, and each ring is saturated. Heterocycloalkyl groups include, but are not limited to, azetidinyl, tetrahydropyrrolyl, tetrahydrofuranyl, morpholinyl, piperidinyl, and the like.

[0207] The term "aryl" refers to a radical having the specified number of carbon atoms (e.g., C 6-10 、C 6-14 ) cyclic groups consisting only of carbon atoms, which are monocyclic or polycyclic, and at least one ring is aromatic (in accordance with Huckel's rule). Aryl groups are connected to other fragments in the molecule through aromatic or non-aromatic rings. Aryl groups include but are not limited to phenyl, naphthyl, etc.

[0208] The term "heteroaryl" refers to a cyclic group having a specified number of ring atoms (e.g., 5-10 members), a specified number of heteroatoms (e.g., 1, 2, or 3), and a specified type of heteroatom (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, furyl, pyrrolyl, thienyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, pyridyl, pyrimidinyl, indolyl, and the like.

[0209] The term "pharmaceutically acceptable salt" refers to a salt formed by reacting a compound with a pharmaceutically acceptable (relatively non-toxic, safe, and suitable for patient use) 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.

[0210] The term "pharmaceutical excipients" refers to excipients and additives used in the production of pharmaceuticals and in the preparation of prescriptions. These excipients are all substances, other than the active ingredient, contained in a pharmaceutical preparation. For details, see the Pharmacopoeia of the People's Republic of China (2020 edition) or the Handbook of Pharmaceutical Excipients (Raymond C. Rowe, 2009).

[0211] The term "treat" refers to therapeutic treatment. When referring to a specific condition, treatment means: (1) alleviating the disease or one or more biological manifestations of the condition, (2) interfering with (a) one or more points in the biological cascade that leads to or causes 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.

[0212] The term "prevent" refers to the reduction of the risk of acquiring or developing a disease or disorder.

[0213] The term "therapeutically effective amount" refers to an amount of a compound that, when administered to a patient, is sufficient to effectively treat a disease or condition described herein. The "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.

[0214] The term "patient" refers to any animal, preferably a mammal, and most preferably a human, that is about to receive or has received a compound or composition according to embodiments of the present invention. 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, and humans, with humans being the most preferred.

[0215] Without violating the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain preferred embodiments of the present invention.

[0216] The reagents and raw materials used in the present invention are commercially available.

[0217] The positive progress of the present invention is that the present invention provides a class of camptothecin compounds with novel structures and antibody-drug conjugates thereof, which have excellent cytotoxic activity and can inhibit the proliferation of tumor cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0218] Figure 1 shows the volume changes of gastric cancer tumor cells under the action of antibody-drug conjugates.

[0219] Figure 2 shows the changes in mouse body weight under the action of antibody-drug conjugates.

[0220] Figure 3 shows the volume changes of breast cancer tumor cells under the action of antibody-drug conjugates.

[0221] Figure 4 shows the changes in mouse body weight under the action of antibody-drug conjugates. DETAILED DESCRIPTION

[0222] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0223] In the following examples, DMAP represents 4-dimethylaminopyridine; rac-BINAP represents 1,1'-binaphthyl-2,2'-bisdiphenylphosphine; and PBS represents phosphate-buffered saline.

[0224] Preparation Example 1: Synthesis of Compound 10

[0225] Under nitrogen, (2-bromoethoxy)(tert-butyl)diphenylsilane (22.5 g, synthesized according 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 confirmed the complete reaction of the raw materials, and the mixture was 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 column chromatography to obtain compound 10 as a colorless oil (12.8 g, yield 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).

[0226] Preparation Example 2: Synthesis of Compounds 10-1, 10-2, 10-3, 10-4 and 10-5

[0227] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-1 was synthesized using (3-bromopropoxy)(tert-butyl)diphenylsilane (prepared with reference to the synthesis method of compound 67 in patent WO2022063278) and 1H-pyrazole-4-carboxaldehyde: 1 H NMR (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).

[0228] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-2 was synthesized using (4-bromobutoxy)(tert-butyl)diphenylsilane (prepared with reference to the synthesis method of compound 70 in patent WO2022063278) and 1H-pyrazole-4-carboxaldehyde: 1 H NMR(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).

[0229] Referring to the synthesis method of compound 10 in Preparation Example 1, compound 10-3 was synthesized using (2-bromoethoxy)(tert-butyl)diphenylsilane and 1H-pyrazole-3-carboxaldehyde (commercially available): 1 H NMR (400MHz, CDCl3) δ9.85 (s, 1H), 7.59 (d, J = 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).

[0230] 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: 1H 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).

[0231] 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).

[0232] Example 1: Preparation of Compounds K1, K2 and K3

[0233] Step 1: Synthesis of compound 2

[0234] To a 250 mL three-necked flask, 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. The mixture was heated to 80°C and stirred under a nitrogen atmosphere for 8 h. After TLC analysis of the reaction, the reaction solution was slowly poured into a mixture of ice and water. The precipitated solid was filtered and dried to obtain 10 g of compound 2 as a brown solid, with a yield of 69%. 1 H NMR (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 + )

[0235] Step 2: Synthesis of compound 3

[0236] 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 stirred at room temperature for 8 h under a nitrogen atmosphere. After TLC analysis of the complete reaction, the reaction solution was washed sequentially with dilute hydrochloric acid, saturated sodium bicarbonate solution, and saturated sodium chloride solution, separated, dried, and concentrated under reduced pressure to obtain 2.2 g of crude product compound 3, which was used directly in the next reaction without further purification.

[0237] Step 3: Synthesis of compound 4

[0238] Acetic acid (50 mL) and compound 3 (2.0 g) were added to a 100 mL single-necked flask. After stirring at room temperature to dissolve, 30% hydrogen peroxide (5.0 mL) was added and the mixture was heated to 70°C with stirring for 3 h. After TLC analysis of the complete reaction of the starting materials, the reaction solution was cooled to room temperature and the acetic acid was evaporated under reduced pressure. The residue was dissolved in chloroform and washed sequentially with saturated sodium bicarbonate solution, purified water, and saturated sodium chloride solution. The mixture was separated, dried, and concentrated under reduced pressure to obtain 1.5 g of crude product compound 4, which was used directly in the next reaction without further purification.

[0239] Step 4: Synthesis of compound 5

[0240] Anhydrous N,N-dimethylformamide (100 mL) and compound 4 (1.00 g) were added to a 100 mL single-necked flask. After complete dissolution, the temperature was lowered to 0°C and oxalyl chloride (0.45 mL) was slowly added dropwise. After the addition was complete, the mixture was warmed to room temperature and stirred for 1 h. After TLC analysis of the reaction, the N,N-dimethylformamide was partially evaporated under reduced pressure. The remaining reaction solution was then slowly poured into a mixture of ice and water to precipitate a solid, which was then filtered. After drying and column chromatography, compound 5 was obtained as a yellow solid (0.8 g, yield 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) + )

[0241] Step 5: Synthesis of compound 6

[0242] To a 100 mL sealed tube, 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. After nitrogen was replaced, the atmosphere was sealed and heated to 100°C with stirring for 15 hours. After TLC analysis of the reaction, the reaction solution was cooled to room temperature, the solvent was evaporated under reduced pressure, and chromatographic separation was performed to yield 3.0 g of compound 6 as a yellow solid, in an 88% yield. 1 H NMR(400 MHz, 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,2H), 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 + )

[0243] Step 6: Synthesis of compound 7

[0244] 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-necked flask and stirred at room temperature for 2 h under a nitrogen atmosphere. After TLC analysis of the reaction, the solvent was evaporated under reduced pressure. The residue was dissolved in chloroform, washed sequentially with purified water and saturated sodium chloride solution, 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) + )

[0245] Step 7: Synthesis of compound 8

[0246] Concentrated sulfuric acid (10 mL) was added to a 10 mL single-necked flask. After cooling to 0°C, compound 7 (1.0 g) was added. The mixture was then heated to room temperature under a nitrogen atmosphere and stirred for 1 h. After TLC analysis of the complete reaction, the reaction solution was slowly poured into a mixture of ice and water. The pH was adjusted to neutral with saturated sodium bicarbonate solution. The precipitated solid was filtered and dried to obtain 0.7 g of compound 8 (80% yield). 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 + )

[0247] Step 8: Synthesis of Compound K1

[0248] To a 10 mL single-necked flask, dichloromethane (10 mL), compound 8 (0.1 g), ethyl azido (0.03 g), and copper tetraacetonitrile hexafluorophosphate (0.02 g) were added and stirred at room temperature under a nitrogen atmosphere for 1.5 h. After TLC analysis of the complete reaction, the reaction solution was washed with purified water and saturated sodium chloride solution, separated, dried, and concentrated under reduced pressure to afford the crude product, which was then separated using a chromatographic column to afford 0.08 g of compound K1 (a 65% yield). 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 + )

[0249] Referring to the above synthesis method, compounds K2 and K3 were synthesized by replacing azidoethanol with azidopropanol and azidobutanol, respectively.

[0250] K2: 1H NMR (400MHz, DMSO) δ9.01 (s, 1H), 8.49 (d, J = 8.0Hz, 1H), 7.94 (d, J = 10.5Hz ,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),2.0 0(m,2H),1.93-1.81(m,2H),0.89(t,J=7.0Hz,3H).MS(ESI)m / z=506.2(M+H + )

[0251] K3: 1 H NMR(400MHz,DMSO)δ9.08(s,1H),8.49(d,J=8.0Hz,1H),7.94(d,J=10.5Hz,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),1.9 3-1.81(m,2H),1.56-1.47(m,2H),0.89(t,J=7.0Hz,3H).MS(ESI)m / z=520.2(M+H + ).

[0252] Example 2: Preparation of Compounds K4, K5, K6, K7, K8 and K9

[0253] Step 1: Synthesis of compound 11

[0254] Under nitrogen protection, compound 9 (1.0 g, 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. At low temperature, a hexane solution of n-butyllithium (2.5 M, 3.5 mL) was added dropwise. After the dropwise addition, a solution of compound 10 (1.5 g) in anhydrous tetrahydrofuran (5 mL) was quickly added and the reaction was continued at -78°C for one hour. After TLC detection of the complete reaction of the raw materials, the reaction was quenched with saturated ammonium chloride solution, extracted with ethyl acetate, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Compound 11 was isolated by column chromatography to obtain 0.6 g of a light yellow oil in a yield of 25%. 1H NMR (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 + )

[0255] Step 2: Synthesis of compound 12

[0256] Under nitrogen, compound 11 (0.6 g) was dissolved in 15 mL of acetonitrile, and manganese dioxide (0.86 g) was added. The mixture was heated under reflux for three hours. After TLC analysis of the reaction, the mixture was filtered through celite, and the filtrate was dried and separated by column chromatography to afford compound 12 as a colorless oil (0.55 g, 92% yield). 1 H 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 + )

[0257] Step 3: Synthesis of compound 13

[0258] Under nitrogen, compound 12 (0.55 g) was dissolved in 10 mL of ethanol, and 3 mL of concentrated hydrochloric acid was added. The mixture was heated under reflux for 3 hours, resulting in the precipitation of a white solid. TLC confirmed the complete reaction of the starting material. The product was filtered and dried to afford 0.19 g of compound 13, in an 80% yield. The product was used directly in the next reaction without further purification.

[0259] Step 4: Synthesis of compound K4

[0260] Under nitrogen, compound 13 (0.19 g) and compound B (0.22 g) were dissolved in 10 mL of toluene and 5 mL of acetic acid and heated to 100°C overnight. TLC confirmed the complete reaction of the starting materials. The product was directly dried and separated by column chromatography to obtain 0.28 g of white solid K4, with a yield of 80%. 1H 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+).

[0261] 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.

[0262] K5: 1 H NMR (400MHz, DMSO) δ8.46(s,1H),8.11(d,J=8.3Hz,1H),8.06(s,1H),7.88(d,J=10.8Hz,1H),7.31(s,1H),6.50(s,1H),5.42(s,2H),5.33-5.12(m, 2H),4.37(t,J=7.1Hz,2H),3.51(t,J=6.1Hz,2H),2.46(s,3H),2.17-1.99 (m,2H),1.96-1.72(m,2H),0.89(t,J=7.3Hz,3H).MS(ESI)m / z=505.2(M+H + ).

[0263] K6: 1 H NMR (400MHz, DMSO) δ8.45 (s, 1H), 8.13 (d, J = 8.3Hz, 1H), 8.07 (s, 1H), 7.90 ( d,J=10.8Hz,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=6.1Hz,2H),2.47(s,3H),2.09-2.00(m,2H),1.93-1.7 1(m,2H),1.56-1.47(m,2H),0.88(t,J=7.3Hz,3H).MS(ESI)m / z=519.2(M+H + ).

[0264] K7: 1 H NMR (400MHz, DMSO) δ8.33(d,J=5.2Hz,1H),8.12(d,J=8.2Hz,1H),8.02(d,J=5.2Hz,1H),7.91(d,J=10.8Hz,1H),7.30(s,1H),5.41(s,2H),5.3 3-5.11(m,2H),4.32(t,J=5.4Hz,2H),3.86(t,J=5.5Hz,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+).

[0265] K8: 1 H NMR (400MHz, DMSO) δ8.31(d,J=5.2Hz,1H),8.14(d,J=8.2Hz,1H),8.04(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 + ).

[0266] K9: 1 H NMR (400MHz, DMSO) δ8.36(d,J=5.2Hz,1H),8.15(d,J=8.2Hz,1H),8.02(d,J=5.2 Hz,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=5.5Hz,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 + ).

[0267] Example 3: Preparation of Compounds I-1 and I-2

[0268] Step 1: Preparation of compound 15

[0269] Under nitrogen, compound K4 (100 mg) and compound 14 (150 mg, CAS: 1599440-06-8, purchased from Hyjea (Chengdu) Pharmaceutical Technology Co., Ltd.) were dissolved in 10 mL of anhydrous tetrahydrofuran. Pyridinium p-toluenesulfonate (25 mg) was added at room temperature and heated to 55°C overnight. The reaction was quenched with saturated sodium bicarbonate solution, extracted with ethyl acetate, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Compound 15 was isolated by column chromatography to yield 50 mg of a white solid in a 30% yield.

[0270] 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 + ).

[0271] Step 2: Preparation of compound 16

[0272] 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 for 2 hours at room temperature, and solid precipitated. TLC monitored the complete reaction of the raw material. The mixture was filtered and dried under vacuum to obtain compound 16 as a light yellow solid (30 mg, yield 83%). The product was used directly in the next reaction without further purification. MS (ESI) m / z = 577.2 (M+H + ).

[0273] Step 3: Preparation of Compound I-1

[0274] Under nitrogen, compound 17 (30 mg) was dissolved in 2 mL of anhydrous N,N-dimethylformamide. 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride (18.5 mg) and N,N-diisopropylethylamine (10 μL) were added at room temperature and allowed to react for 2 hours. After the reaction solution became clear, compound 16 (30 mg) was added at room temperature and allowed to react overnight. LC-MS confirmed the complete reaction of raw material 16. The product was then directly spin-dried and purified on a C18 reverse-phase column to obtain compound I-1 as a light yellow solid (27 mg, 50% yield).

[0275] 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),7.90(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 + ).

[0276] Referring to the preparation method of I-1, Compound K4 was replaced by Compound K1. Compound I-2 was obtained by the same method as above.

[0277] I-2: 1H NMR (400MHz, DMSO) δ8.70(t,J=6.6Hz,1H),8.26(t,J=5.6Hz,1H),8.13-8.10(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 + ).

[0278] Example 4: Synthesis of Compounds II-1 and II-2

[0279] The HER2 antibody is trastuzumab.

[0280] At 37 ° C, the antibody Trastuzumab (HER2 antibody, CAS: 180288-69-1, purchased from Hangzhou Haoyang Biotechnology Co., Ltd.) was added to a PBS buffered aqueous solution (pH = 6.5 0.05M PBS buffered aqueous solution; 10.0 mg / mL, 1.0 mL, 67.6 nmol) of tris (2-carboxyethyl) phosphine (TCEP) aqueous solution (10 mM, 37.2 μL, 372 nmol), placed in a water bath shaker, and oscillated at 37 ° C for 3 hours before stopping the reaction. The reaction solution was cooled to 25 ° C with a water bath. Compound I-1 or I-2 (1014 nmol) was dissolved in 50 μL DMSO, added to the above reaction solution, placed in a water bath shaker, and oscillated at 25 ° C for 3 hours before stopping 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 conjugates II-1 and II-2, which were stored at 4°C.

[0281] The average drug loading values ​​calculated by RP-HPLC were: II-1, t=7.8; II-2, t=7.7.

[0282] Example 5: Preparation of Compound I-3

[0283] Step 1: Preparation of compound 19

[0284] Under nitrogen, compound 18 (1.2 g, CAS: 236426-37-2, purchased from Jier Biochemical Co., Ltd.) was dissolved in anhydrous tetrahydrofuran (10 mL). Diethylamine (3 mL) was added at room temperature and allowed to react for 2 h. TLC analysis revealed no residual starting material, so the reaction was terminated. The reaction solution was then concentrated to dryness, dissolved in dichloromethane, and concentrated to dryness to afford crude compound 19, a viscous liquid (0.7 g), in a 96.9% yield. MS (ESI) m / z = 336.2 (M+H+).

[0285] Step 2: Preparation of compound 21

[0286] Under nitrogen, compound 19 (0.7 g) was dissolved in acetonitrile (10 mL). 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 overnight. The mixture was extracted with saturated sodium bicarbonate solution and ethyl acetate, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Compound 21 was isolated by column chromatography to yield 1.3 g of a colorless liquid in a 68.4% yield. MS (ESI) m / z = 910.5 (M+H+).

[0287] Step 3: Preparation of compound 22

[0288] Under nitrogen, 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 and allowed to react overnight. TLC analysis revealed no residual starting material, so the reaction was terminated. The reaction solution was concentrated to dryness, then stripped of the solvent with dichloromethane, concentrated under reduced pressure, and separated by column chromatography to afford compound 22 as a colorless oil (0.8 g, yield 66.1%).

[0289] 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=13.8,5.0Hz,1H),2.90(dd,J=13.7,9.0Hz,1H),2.40(t,J=6.5Hz,2H),2.34(t,J=7.3Hz,2H). MS(ESI)m / z=854.4(M+H+).

[0290] Step 4: Preparation of compound I-3

[0291] Under nitrogen, 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 reacted for 2 hours. After the reaction solution became clear, compound 16 (70 mg) was added at room temperature and reacted overnight. LC-MS monitoring confirmed the complete reaction of raw material 16. After concentration under reduced pressure, the mixture was separated by column chromatography to obtain compound I-3 as a light yellow solid (35 mg, 50% yield).

[0292] 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+).

[0293] Example 6: Preparation of Compound I-4

[0294] Step 1: Preparation of compound 24

[0295] Under nitrogen, compound 19 (300 mg) was dissolved in acetonitrile (10 mL). Compound 23 (820 mg, CAS: 1334170-03-4, purchased from Shanghai Bidex Pharmaceuticals Co., Ltd.) was added at room temperature and heated to 45°C overnight. The mixture was extracted with saturated sodium bicarbonate solution and ethyl acetate, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Compound 24 was isolated by column chromatography to yield 600 mg of a colorless oil in a 68.4% yield. MS (ESI) m / z = 981.5 (M+H+).

[0296] Step 2: Preparation of compound 25

[0297] Under nitrogen, compound 24 (600 mg) was dissolved in anhydrous tetrahydrofuran (10 mL). 1,8-diazobisspiro[5.4.0]undec-7-ene (DBU) (100 mg) was added at room temperature and allowed to react for 2 h. TLC analysis revealed no residual starting material, so the reaction was terminated. The reaction solution was then concentrated to dryness and then stripped of solvent with dichloromethane to dryness to afford crude compound 25 as a colorless oil (420 mg, 91.3% yield). MS (ESI) m / z = 759.4 (M+H+).

[0298] Step 3: Preparation of compound 27

[0299] Under nitrogen, compound 25 (400 mg) was dissolved in anhydrous tetrahydrofuran (20 mL). 1-Hydroxybenzotriazole (HOBT) (100 mg), 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 allowed to react overnight. LC-MS confirmed the complete reaction of starting material 25. After concentration under reduced pressure, compound 27 was isolated by column chromatography to yield 450 mg of a colorless oil in an 84.9% yield. MS (ESI) m / z = 1009.5 (M+H+).

[0300] Step 4: Preparation of compound 28

[0301] Under nitrogen, compound 27 (400 mg) was dissolved in dichloromethane (10 mL), and trifluoroacetic acid (1.5 mL) was added at room temperature. The mixture was allowed to react overnight. LCMS analysis revealed no residual starting material, so the reaction was stopped and the reaction solution was concentrated to dryness, slurried with tert-butyl methyl ether, and filtered under reduced pressure to afford compound 28 as a light yellow solid (350 mg, 92.8% yield).

[0302] 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+).

[0303] Step 5: Preparation of compound I-4

[0304] Under nitrogen, compound 16 (60 mg) was dissolved in anhydrous tetrahydrofuran (10 mL), and 1-hydroxybenzotriazole (HOBT) (17 mg) was added at room temperature. The mixture was allowed 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 allowed to react overnight. LC-MS confirmed the complete reaction of compound 16. After concentration under reduced pressure, the mixture was separated by column chromatography to afford compound I-4 as a pale yellow solid (30 mg, yield 19.1%).

[0305] 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+).

[0306] Example 7: Preparation of Compounds II-3 and II-4

[0307] 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.

[0308] Effect Example 1: Effects of Camptothecin Derivatives K1-K9 on Tumor Cell Proliferation

[0309] Camptothecin's ability to test tumor cell proliferation:

[0310] 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, the test cells (see Table 1) were resuspended and counted. The supernatant was removed by centrifugation and the cell density was adjusted. Count the cells using a cell counter. Aspirate 20 μl of the cell suspension, mix with 20 μl of trypan blue, and take 20 μl of the liquid for cell counting. Plate the cells in a 96-well cell culture plate, adding 180 μl to each well, for a total of 1,000 cells per well. Gently tap to mix, and incubate the cell culture plate in a 37°C cell culture incubator for 16 hours. Dilute the compound with McCoy's 5A medium, adding 20 μl to each well to a maximum concentration of 100 nM. Three-fold dilutions were performed, with 10 points plated. The vehicle control was DMSO; 20 μl of McCoy's 5A medium was added to the blank control. Gently tap to mix, then place the cell culture plate in a 37°C cell culture incubator and incubate for 7 days. After 7 days of culture, remove the plate from the incubator, aspirate the culture medium, add 20 μl of culture medium, and then add 20 μl of CTG to each well. Oscillate on a shaker for 5 minutes, let stand at room temperature for 10 minutes, and transfer 30 μl of the reaction mixture to a Viewplate-96white, white, clear-bottomed microtiter plate for data analysis using an EnVision plate reader.

[0311] Calculation formula: background value = control group - blank group; inhibition rate = 1 - (experimental group - blank group) / (background value) * 100%.

[0312] Table 1. Overview of cell lines used in this screening

[0313] Table 2. Effects of compounds on tumor cell proliferation

[0314] As shown in Table 2, the compounds of the present invention have better in vitro cell activity.

[0315] Effect Example 2: Effect of Antibody-Antibody Drug Conjugates on Tumor Cell Proliferation Ability

[0316] Test method for the tumor cell proliferation ability of compounds II-1, II-2, II-3 and II-4:

[0317] After digesting NCI-N87 cells, resuspend and count the cells. Centrifuge and remove the supernatant. Adjust the cell density. Count the cells using a cell counter. Aspirate 20 μL of the cell suspension and mix with 20 μL of VisStain AOPI Staining Solution. Count the cells using a 20 μL cell count. Plate the cells in a 96-well cell culture plate, adding 180 μL per well to seed 1000 or 2000 cells per well. Gently tap to mix, and incubate the cell culture plate at 37°C for 16 hours. Dilute the compound in RPMI1640 medium / 10% FBS and add 20 μL per well to a maximum concentration of 100 nM. Plate 10 points with 3-fold dilutions. For a vehicle control, use DMSO. Add 20 μL of RPMI1640 medium / 10% FBS to the blank control. Gently tap to mix, and incubate the cell culture plate at 37°C for 7 days. After 7 days of culture, remove the cell plate from the incubator, aspirate the culture medium, add 20 μL of culture medium, and then add 20 μL of CTG to each well. Oscillate on a shaker for 5 minutes, let it stand at room temperature for 10 minutes, and transfer 30 μL of the reaction solution to a Viewplate-96white, white, clear-bottomed microtiter plate for data analysis using an EnVision plate reader.

[0318] Calculation formula: The inhibition rate (IR) of the test antibody was calculated using the following formula: IR (%) = (1 - (antibody - blank control) / (vehicle control - blank control)) * 100%. The inhibition rates of different antibody concentrations were calculated in Excel, and the relevant parameters were calculated using GraphPad Prism software. The results are shown in Table 3.

[0319] Table 3. Effects of compound NCl-N87 on tumor cell proliferation

[0320] Effect Example 3: Bystander Effects of Antibody Drug Conjugate II-2 and T-Dxd on NCI-N87 and MDA-MB-231 Cells

[0321] In this experiment, II-2 and T-Dxd were co-cultured with NCI-N87 / MDA-MB-231 cells for 7 days. The proportion of NCI-N87 or MDA-MB-231 cells in the total number of particles was detected by flow cytometry to reflect the ability of ADC to kill negative cells through the bystander effect.

[0322] NCI-N87 cells were cultured in a T175 culture flask. After digestion, the cells were resuspended in 8ml of suspension 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, the cells were resuspended in 6ml of suspension and counted. The supernatant was removed by centrifugation to adjust the cell density. Count the cells using a cell counter. Pipette 20μl of the cell suspension and mix with 20μl of VisStain AOPI Staining Solution. Take 20μl of the liquid and count the cells. Plate the cells in 96-well cell culture plates (flat bottom) using RPMI1640 medium / 10% FBS. Add 90μl of each cell to each well, resulting in a cell ratio of 10,000 NCI-N87 cells / well and 2,000 MDA-MB-231 cells / well (5:1) per well. Gently tap to mix, and incubate the cell culture plates in a 37°C 5% CO2 cell culture incubator for 16 hours. Antibody dilution: First, dilute the antibody stock solution to 10ug / ml using RPMI1640 medium / 10% FBS. Add 20ul of the stock solution to each well. Add 20ul of RPMI1640 medium / 10% FBS to the blank control. Gently tap to mix thoroughly and incubate the cell culture plate in a 37°C, 5% CO2 cell culture incubator for 7 days. After 7 days of culture, remove the cell plate from the incubator, aspirate the culture medium, add 100ul of trypsin, and incubate in a 37°C cell culture incubator for 15 minutes. Add 100ul of RPMI1640 medium / 10% FBS, pipette to detach the cells from the bottom of the wells, and transfer to a 96-well cell culture plate (V-bottom). Centrifuge at 350g for 5 minutes and remove the supernatant. Prepare trastuzumab at a concentration of 1ug / ml in PBS containing 2% FBS. Add 100ul of trastuzumab to each tube and incubate at 4°C for 1 hour. Centrifuge at 350g for 5 minutes and remove the supernatant. Dilute the secondary antibody, PE-labeled human IgG, 1:2000 in PBS containing 2% FBS. Add 100 μl to each well and incubate at 4°C for 0.5 h. Centrifuge at 350 g for 5 minutes, remove the supernatant, and resuspend in 100 μl of PBS containing 2% FBS in preparation for analysis. The results are shown in Table 4 below.

[0323] 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%.

[0324] Table 4

[0325] 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.

[0326] Effect Example 4. Antitumor efficacy test of II-1 and II-2 on the NOG mouse subcutaneous transplantation NCI-N87 cell animal model

[0327] In this study, NCI-N87 cells were subcutaneously inoculated into NOG mice to determine the anti-tumor effects of Ⅱ-1 and Ⅱ-2.

[0328] NOG mice: Female NOG mice (6 weeks old) were purchased from Beijing Weitonglihua Laboratory Animal Technology Co., Ltd. The mice were acclimated for 7 days after arrival before the study began.

[0329] 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 size was 1×10 7 ) were subcutaneously inoculated into the right axilla of female NOG mice to establish the NCI-N87 tumor-bearing mouse model.

[0330] Dosage:

[0331] On the 10th day after tumor cell inoculation, the tumor volume of each mouse was detected, and mice with a tumor volume of 110 mm were selected. 3 ~250mm 3 Mice within the range were divided into groups based on tumor volume (5 mice per group) and administered with 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.), and II-1 and II-2 on day 11 after inoculation. Tumor volume and body weight of mice in each group were monitored twice a week for 3 consecutive weeks during administration. Body weight and tumor volume were measured before each administration. Tumor volume inhibition rate (TGI%) was calculated on day 23 after administration using the following formula: TGI (%) = [1-(Ti - T0) / (Vi - V0)] × 100; where Ti is the mean tumor volume of the treatment group, T0 is the mean tumor volume of the treatment group on day D0, Vi is the mean tumor volume of the isotype control group, and V0 is the mean tumor volume of the isotype control group on day D0. Tumor volume measurement: The long diameter (a) and wide diameter (b) of the tumor were measured using a vernier caliper. The tumor volume was calculated using the following formula: TV = 1 / 2 × a × b 2 Body weight was measured using an electronic balance.

[0332] The dosage and method of administration are shown in Table 5 below.

[0333] Table 5. Dosage study design

[0334] As shown in Table 6 and Figure 1, on day 23 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.

[0335] Table 6. Antibody-drug conjugates' ability to inhibit tumor growth in vivo on day 23

[0336] Note: P value is compared with negative control antibody

[0337] 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 ( FIG. 2 ).

[0338] Effect Example 5. Antitumor efficacy test of II-1 and II-2 on the NOG mouse subcutaneous transplantation JIMT-1 cell animal model

[0339] In this study, JIMT-1 cells were subcutaneously inoculated into NOG mice to determine the anti-tumor effects of Ⅱ-1 and Ⅱ-2.

[0340] NOG mice: Female NOG mice (6 weeks old) were purchased from Beijing Weitonglihua Laboratory Animal Technology Co., Ltd. The mice were acclimated for 7 days after arrival before the study began.

[0341] 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.

[0342] Dosage:

[0343] On the 10th day after tumor cell inoculation, the tumor volume of each mouse was detected, and mice with a tumor volume of 110 mm were selected. 3 ~250mm 3Mice within the range were divided into groups according to tumor volume (5 mice per group) and administered once on the 11th and 18th days after inoculation, respectively, with negative control antibodies (human IgG Control, source: Hangzhou Haoyang Biotechnology Co., Ltd., catalog number: HSP067-F1), II-1 and II-2. During the administration period, the changes in tumor volume and body weight of mice in each group were monitored twice a week for 4 consecutive weeks. Body weight and tumor volume were measured before each administration. The tumor volume inhibition rate (TGI%) was calculated on the 28th day after administration. The calculation formula is as follows: TGI (%) = [1-(Ti-T0) / (Vi-V0)] × 100; where Ti: mean tumor volume of the administration group, T0: mean tumor volume of the 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 with a vernier caliper. The tumor volume was calculated according to the following formula: TV = 1 / 2 × a × b 2 Body weight was measured using an electronic balance.

[0344] The dosage and method of administration are shown in Table 7.

[0345] Table 7. Dosage study design

[0346] As shown in Table 8 and Figure 3, on day 28 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.

[0347] Table 8. ADC ability to inhibit tumor growth in vivo

[0348] Note: P value is compared with negative control antibody

[0349] 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 the 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 defined as 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 connected to the 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 -, where 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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