Gramine-platinum(IV) complex, its preparation method and antitumor use

Abstract

The present disclosure relates to gramine-platinum(IV) complexes, their preparation methods, and antitumor applications. Mono-substituted tetravalent platinum complexes are formed by introducing one gramine molecule into one axial side of the platinum(IV) coordination center, or di-substituted tetravalent platinum complexes are formed by introducing one gramine molecule into one axial side of the platinum(IV) coordination center and one -NH- aliphatic group or aliphatic group into the other axial side. The prepared complexes have stronger tumor cell killing abilities and significantly improved antiproliferative activity in multiple cell lines, with the most significant improvement in highly malignant triple-negative breast cancer cells compared to clinical platinum preparations. The gramine-platinum(IV) complexes of the present disclosure have advantages such as a simple synthesis process, low cost, and significantly improved therapeutic efficacy in drug combination therapy, with better therapeutic efficacy and fewer side effects compared to conventional divalent platinum and similar tetravalent platinum preparations.

Description

[Technical Field]

[0001] The present disclosure belongs to the technical field of anti-cancer chemical agents, and in particular to gramine-platinum(IV) complexes and their preparation methods and anti-tumor applications. [Background technology]

[0002] Cancer is a serious disease that threatens human life and health worldwide, with incidence rates increasing year by year and extremely high mortality rates. The World Health Organization's (WHO) International Agency for Research on Cancer (IARC) has released the latest global cancer burden data for 2020, which includes statistics on the incidence and mortality rates of 36 types of cancer in 185 countries, as well as cancer incidence trends. In 2020, an estimated 19.3 million new cancer cases and approximately 10 million cancer deaths were reported worldwide. The top 10 cancers with the highest incidence rates worldwide are breast cancer (2.26 million cases, 11.7%), lung cancer (2.21 million cases, 11.4%), colorectal cancer (1.88 million cases, 9.8%), prostate cancer (1.41 million cases, 7.3%), skin cancer (1.2 million cases, 6.2%), stomach cancer (1.09 million cases, 5.6%), liver cancer (0.91 million cases, 4.7%), cervical cancer (0.6 million cases, 3.1%), esophageal cancer (0.6 million cases, 3.1%), and thyroid cancer (0.59 million cases, 3%). These 10 cancer types account for 63% of the total number of new cancer cases.

[0003] Chemotherapy and radiation therapy are the primary means of cancer treatment, and chemotherapy is irreplaceable in tumor treatment. Therefore, the research and development of chemotherapeutic drugs remains a focus of research. Platinum compounds, such as cisplatin, oxaliplatin, and carboplatin, are important clinical agents for tumor treatment and are well known for their use in the treatment of breast cancer, bladder cancer, lung cancer, and malignant lymphoma. Platinum compounds primarily target DNA, exhibiting remarkable anticancer effects, strong anticancer activity, and little cross-resistance with other anticancer drugs, making them advantageous for clinical drug combination therapy and exhibiting a wide range of anticancer activity. However, toxic side effects and drug resistance limit the clinical application of platinum compounds, making the discovery of new platinum compounds a focus of research. Pt(IV) complexes have the potential for broad application due to their diverse activity and low systemic toxicity.

[0004] Pt(IV) is a product of the oxidation of cisplatin, oxaliplatin, and other compounds. Compared to divalent platinum, Pt(IV) has an octahedral structure and is pharmacokinetically inactive, which improves its stability in the bloodstream, prolongs the duration of action of platinum compounds, and enhances their antitumor activity. Furthermore, Pt(IV) is highly lipophilic and readily absorbed by cancer cells. Chemical modification can also be used to introduce different functional molecules into the two axial sites of Pt(IV) to enhance its selectivity for cancer cells and improve its pharmacological properties, thereby achieving effects such as targeting and synergistic sensitization.

[0005] Natural products play an important role in pharmaceutical research and development due to their unique advantages, such as low toxicity, immune protection, and cardiovascular protection. Gramine (GM) is a natural indole alkaloid with various pharmacological activities, including anti-inflammatory, antitumor, antibacterial, and antioxidant properties. Gramine exerts antitumor effects by regulating various signaling pathways and significantly suppressing tumor growth and metastasis by inhibiting transforming growth factor (TGF-β). This mechanism involves inhibiting the cell cycle, promoting cell apoptosis, inhibiting tumor angiogenesis, inhibiting the occurrence of EMT, and inhibiting tumor invasion and metastasis. Therefore, the present disclosure aims to achieve a synergistic sensitizing effect by introducing gramine as a functional ligand into the axial position of tetravalent platinum and synthesizing a gramine-platinum(IV) prodrug. Summary of the Invention

[0006] To solve the above technical problems, the present disclosure provides a gramine-platinum(IV) complex and its preparation method and antitumor application.

[0007] The technical solution adopted in the present disclosure is a gramine-platinum(IV) complex in which a gramine group is attached to one axial side of a tetravalent platinum coordination center, or a gramine group is attached to one axial side of a tetravalent platinum coordination center and an -NH- aliphatic chain group or an aliphatic chain group is attached to the other axial side.

[0008] In some embodiments, the structure of the gramine-platinum(IV) complex is shown in Formula 1: [ka] where R is a hydrogen atom, -C(O)-R2, a deuterium atom, or C 1-6 is an alkyl group, [ka] is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin, or miriplatin; Preferably, [ka] is cisplatin, oxaliplatin or carboplatin; R1 is -C n H 2n -, n is an integer, 1≦n≦6, preferably -C n H 2n - is a straight chain group, R2 is -C m H 2m+1 or -NH-C m H 2m+1 and m is an integer, 1≦m≦20, and preferably -C m H 2m+1 or -NH-C m H 2m+1 is a straight chain group.

[0009] In some embodiments, the structure of the gramine-platinum(IV) complex is shown in Formula 1-1 or Formula 1-2: [ka] where: [ka] is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin, or miriplatin; and R1 is -C n H 2n where n is an integer and 1≦n≦6; R2 is -C m H 2m+1 or -NH-C m H 2m+1 where m is an integer and 1≦m≦20.

[0010] In some embodiments, the gramine-platinum(IV) complex comprises: [ka] is cisplatin, oxaliplatin or carboplatin.

[0011] In some embodiments, the gramine-platinum(IV) complex comprises -C n H 2n - is a straight chain group and n is 1 or 2.

[0012] In some embodiments, the gramine-platinum(IV) complex comprises -C m H 2m+1 or -NH-C m H 2m+1 is a straight chain group.

[0013] In some embodiments, the gramine-platinum(IV) complex comprises -C n H 2n - is a straight chain group.

[0014] In some embodiments, the gramine-platinum(IV) complex comprises -C m H 2m+1 -or-NH-C m H 2m+1 - is a straight chain group, and m is 6≦m≦17, preferably 6≦m≦15, and more preferably 6, 8, 12 or 15.

[0015] In some embodiments, the structure of the gramine-platinum(IV) complex is represented by any one of formulas 2 to 10: [ka]

[0016] The present disclosure further provides a method for preparing a gramine-platinum(IV) complex, the method comprising the steps of: esterifying a compound of formula 11 with a compound of formula 17 in the presence of a first condensing agent and a first acid scavenger to obtain a compound of formula 1; [ka] In particular, a compound of formula 11 and a compound of formula 12 are subjected to an esterification reaction in the presence of a first condensing agent and a first acid scavenger to obtain a compound of formula 1-1, [ka] where: R is a hydrogen atom, -C(O)-R2, a deuterium atom, or C 1-6 is an alkyl group, [ka] is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin, or miriplatin; and R1 is -C n H 2n -, n is an integer, and 1≦n≦6.

[0017] In some embodiments, the method for preparing a gramine-platinum(IV) complex comprises: [ka] is cisplatin, oxaliplatin or carboplatin.

[0018] In some embodiments, the gramine-platinum(IV) complex comprises -C n H 2n - is a straight chain group.

[0019] In some embodiments, in the method for preparing a gramine-platinum(IV) complex, the first condensing agent is TBTU, the first acid scavenger is triethylamine, and the ratio of raw materials in the reaction is 1-1.2:1:1.2-2:1.2-2 (compound of formula 11:compound of formula 17 or compound of formula 12:first condensing agent:first acid scavenger).

[0020] In some embodiments, the reaction is carried out under conditions of protection from light and inert gas.

[0021] In some embodiments, a method for preparing a gramine-platinum(IV) complex comprises the steps of: esterifying a compound of formula 1-1 with a compound of formula 13 or a compound of formula 14 to obtain a compound of formula 1-2; [ka] where: m is an integer, and 1≦m≦20.

[0022] In some embodiments, the gramine-platinum(IV) complex comprises -C m H 2m+1 is a straight chain group.

[0023] In some embodiments, a method for preparing a gramine-platinum(IV) complex comprises the steps of: acylation of a gramine of Formula 15 with a compound of Formula 16 in the presence of a second condensing agent and a second acid scavenger to obtain a compound of Formula 11; [ka] In some embodiments, the second condensing agent is DMAP and the second acid scavenger is triethylamine.

[0024] The present disclosure further provides an isotopic variant of the gramine-platinum(IV) complex. In some embodiments, the isotopic variant is a deuterated variant.

[0025] The present disclosure further provides a pharmaceutical composition comprising at least one therapeutically effective amount of the gramine-platinum(IV) complex or an isotopic derivative thereof and a pharmaceutically acceptable excipient.

[0026] In some embodiments, the unit dose of the pharmaceutical composition is 0.001 mg to 1000 mg.

[0027] In some embodiments, the pharmaceutical composition contains 0.01 to 99.99% of the gramine-platinum(IV) complex or its isotopic derivative, based on the total weight of the composition. In some embodiments, the pharmaceutical composition contains 0.1 to 99.9% of the gramine-platinum(IV) complex or its isotopic derivative. In some embodiments, the pharmaceutical composition contains 0.5 to 99.5% of the gramine-platinum(IV) complex or its isotopic derivative. In some embodiments, the pharmaceutical composition contains 1 to 99% of the gramine-platinum(IV) complex or its isotopic derivative. In some embodiments, the pharmaceutical composition contains 2 to 98% of the gramine-platinum(IV) complex or its isotopic derivative.

[0028] In some embodiments, the pharmaceutical composition contains 0.01-99.99% pharmaceutically acceptable excipients, based on the total weight of the composition. In some embodiments, the pharmaceutical composition contains 0.1-99.9% pharmaceutically acceptable excipients. In some embodiments, the pharmaceutical composition contains 0.5-99.5% pharmaceutically acceptable excipients. In some embodiments, the pharmaceutical composition contains 1-99% pharmaceutically acceptable excipients. In some embodiments, the pharmaceutical composition contains 2-98% pharmaceutically acceptable excipients.

[0029] Alternatively, the present disclosure further provides a compound of formula 11 or a pharmaceutically acceptable salt thereof: [ka] , where R1 is -C n H 2n -, n is an integer, and 1≦n≦6.

[0030] In some embodiments, the —C in the compound of formula 11 n H 2n - is a straight chain group. In some embodiments, the compound of formula 11 is [ka] is selected from.

[0031] The present disclosure further provides a use of the gramine-platinum(IV) complex or an isotopic derivative thereof, or the compound of formula 11 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition in the preparation of an antitumor drug.

[0032] In some embodiments, the tumor is selected from breast cancer (e.g., triple-negative breast cancer), colorectal cancer, cervical cancer, head and neck cancer (e.g., pharyngeal squamous cell carcinoma), bladder cancer, ovarian cancer, pancreatic cancer, liver cancer, and lung cancer.

[0033] On the other hand, the present disclosure further provides a method for treating / preventing tumors by administering to an individual a therapeutically effective amount of a gramine-platinum(IV) complex or an isotopic substitution thereof, or a compound of Formula 11 or a pharmaceutically acceptable salt thereof, or the pharmaceutical composition. In some embodiments, the tumors include, but are not limited to, breast cancer (e.g., triple-negative breast cancer), colorectal cancer, cervical cancer, pharyngeal squamous cell carcinoma, bladder cancer, ovarian cancer, pancreatic cancer, liver cancer, and lung cancer.

[0034] The present disclosure further provides the use of the gramine-platinum(IV) complex or an isotopic substitution thereof, or the compound of formula 11 or a pharmaceutically acceptable salt thereof, or said pharmaceutical composition in tumor treatment / prevention.

[0035] In some embodiments, the tumor includes, but is not limited to, breast cancer (e.g., triple-negative breast cancer), colorectal cancer, cervical cancer, head and neck cancer (e.g., pharyngeal squamous cell carcinoma), bladder cancer, ovarian cancer, pancreatic cancer, liver cancer, and lung cancer.

[0036] On the other hand, the present disclosure further provides the use of said gramine-platinum(IV) complex or its isotopic substitutions in combination with an immunosuppressant in the preparation of an antitumor drug.

[0037] In some embodiments, the tumor includes, but is not limited to, breast cancer (e.g., triple-negative breast cancer), colorectal cancer, cervical cancer, head and neck cancer (e.g., pharyngeal squamous cell carcinoma), bladder cancer, ovarian cancer, pancreatic cancer, liver cancer, and lung cancer.

[0038] In some embodiments, the immunosuppressant is selected from an anti-PD-1 antibody or antigen-binding fragment thereof, a PD-L1 antibody or antigen-binding fragment thereof, or an anti-CTLA-4 antibody or antigen-binding fragment thereof.

[0039] In some embodiments, the anti-PD-1 antibody or antigen-binding fragment thereof includes, but is not limited to, pembrolizumab, nivolumab, camrelizumab, toripalimab, tislelizumab, cemiplimab, sintilimab, CS-1003, HLX-10, SCT-I10A, sasanlimab, spartalizumab, MGD-013, retifanlimab, MEDI-0680, BAT-1306, MEDI-5752, LZM-009, JTX-4014, BI-754091, AK-104, BCD-217, balstilimab, AK-103, or cetrelimab. In some embodiments, the anti-PD-1 antibody or antigen-binding fragment thereof is camrelizumab. In some embodiments, the anti-PD-1 antibody or antigen-binding fragment thereof is toripalimab. In some embodiments, the anti-PD-1 antibody or antigen-binding fragment thereof is Tislelizumab. In some embodiments, the anti-PD-1 antibody or antigen-binding fragment thereof is Cemiplimab.

[0040] In some embodiments, the anti-PD-L1 antibody or antigen-binding fragment thereof is chosen from Atezolizumab, Avelumab, Durvalumab, Adebrelimab, Envafolimab, CS-1001, TQB-2450, KL-A167, IMC-001, or CX-072. In some embodiments, the anti-PD-L1 antibody or antigen-binding fragment thereof is Adebrelimab.

[0041] In some embodiments, the anti-PD-1 antibody or antigen-binding fragment thereof is selected from ipilimumab or tremelimumab.

[0042] In some other embodiments, the dose of the immunosuppressant is 0.1 to 10.0 mg / kg, and is 0.1 mg / kg, 0.2 mg / kg, 0.3 mg / kg, 0.4 mg / kg, 0.5 mg / kg, 0.6 mg / kg, 0.7 mg / kg, 0.8 mg / kg, 0.9 mg / kg, 1.0 mg / kg, 1.2 mg / kg, 1.4 mg / kg, 1.6 mg / kg, 1.8 mg / kg, 2.0 mg / kg, 2.2 mg / kg, 2.4 mg / kg, 2.6 mg / kg, 2.8 mg / kg, 3.0 mg / kg, 3.2 mg / kg, 3.4 mg / kg, 3.6 mg / kg, 3.8 mg / kg, 4.0 mg / kg, 4.2 ... mg / kg, 4.4 mg / kg, 4.6 mg / kg, 4.8 mg / kg, 5.0 mg / kg, 5.2 mg / kg, 5.4 mg / kg, 5.6 mg / kg, 5.8 mg / kg, 6.0 mg / kg, 6.2 mg / kg, 6.4 mg / kg, 6.6 mg / kg, 6.8 mg / kg, 7.0 mg / kg, 7.2 mg / kg, 7.4 mg / kg, 7.6 mg / kg, 7.8 mg / kg, 8.0 mg / kg, 8.2 mg / kg, 8.4 mg / kg, 8.6 mg / kg, 8.8 mg / kg, 9.0 mg / kg, 9.2 mg / kg, 9.4 mg / kg, 9.6 mg / kg, 9.8 mg / kg, or 10.0 mg / kg.

[0043] The present disclosure further provides the gramine-platinum(IV) complex or its isotopic derivative for treating tumors in combination with an immunosuppressant.

[0044] The present disclosure further provides an immunosuppressant for treating tumors in combination with the gramine-platinum(IV) complex or its isotopic derivative.

[0045] The present disclosure further provides a composition comprising an immunosuppressant, the gramine-platinum(IV) complex or an isotopic derivative thereof, and a pharmaceutically acceptable excipient.

[0046] The present disclosure further provides a method for treating tumors, comprising administering to a patient an effective amount of the gramine-platinum(IV) complex or an isotopic derivative thereof and an immunosuppressant.

[0047] The compounds of the present disclosure may exist in particular geometric or stereoisomeric forms. The present disclosure contemplates all such compounds, including cis- and trans-isomers, (-)- and (+)-enantiomers, (R)- and (S)-enantiomers, diastereomers, (D)-isomers, (L)-isomers, and racemic and other mixtures thereof, such as enantiomerically or diastereomerically enriched mixtures, and all such mixtures are within the scope of the present disclosure. Additional asymmetric carbon atoms may be present in substituents such as alkyl groups. All such isomers and mixtures thereof are included within the scope of the present disclosure. Compounds of the present disclosure containing asymmetric carbon atoms may be isolated in optically pure or racemic form. Optically pure forms can be separated from racemic mixtures or synthesized using chiral starting materials or chiral reagents.

[0048] Optically active (R)- and (S)-isomers, as well as D- and L-isomers, may be prepared by chiral synthesis, chiral reagents, or other conventional techniques. If a single enantiomer of a compound of the present disclosure is desired, it may be prepared by asymmetric synthesis or derivatization with a chiral auxiliary, separating the resulting diastereomeric mixture, and cleaving the auxiliary to provide the pure desired enantiomer. Alternatively, if the molecule contains a basic (e.g., amino) or acidic (e.g., carboxyl) functional group, forming a diastereomeric salt with an appropriate optically active acid or base, then separating the diastereomers by conventional methods known in the art, followed by recovery of the pure enantiomer. Separation of enantiomers and diastereomers is also often accomplished using chromatography, which utilizes a chiral stationary phase and optionally combines with chemical derivatization methods (e.g., formation of carbamates from amines).

[0049] JPEG2025539809000017.jpg31169 [ka] is expressed as [ka] It may be expressed as:

[0050] The present disclosure further includes some isotopically labeled compounds of the present disclosure that are identical to those described herein, except that one or more atoms have been replaced with an atom having an atomic mass or mass number different from the atomic mass or mass number normally found in nature. Examples of isotopes that can be attached to compounds of the present disclosure include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, iodine, and chlorine, such as 2 H, 3 H, 11 C. 13 C. 14 C. 13 N, 15 N, 15 O. 17 O. 18 O. 31P, 32 P, 35 S, 18 F, 123 I, 125 I and 36 Includes CI etc.

[0051] Unless otherwise specified, when a position is specifically designated as deuterium (D), it is understood that the position has a natural abundance of deuterium at least 1000 times greater than the natural abundance of deuterium (0.015%) (i.e., at least 10% deuterium inclusion). Example compounds may contain at least 1000, 2000, 3000, 4000, 5000, 6000, or more times the natural abundance of deuterium. The present disclosure further includes various deuterated forms of compounds of formula (I). Each available hydrogen atom bonded to a carbon atom may be independently replaced with a deuterium atom. Those skilled in the art can synthesize deuterated forms of compounds of formula (I) by referring to relevant literature. When preparing deuterated forms of the compound of formula (I), commercially available deuterated starting materials can be used or can be synthesized by conventional techniques with deuterated reagents, including, but not limited to, deuterated borane, tritiated borane in tetrahydrofuran, deuterated lithium aluminum hydride, deuterated iodoethane, deuterated iodomethane, and the like.

[0052] A "fatty chain group" or "aliphatic group" is a group composed of carbon or hydrogen, typically having a straight or branched chain structure.

[0053] "C 1-6 "Alkyl group" refers to a saturated straight or branched chain aliphatic hydrocarbon group having 1 to 6 (e.g., 1, 2, 3, 4, 5, or 6) carbon atoms. Non-limiting examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, n-hexyl, and the like.

[0054] The term "pharmaceutical composition" is intended to include a mixture of one or more compounds described herein, or physiologically acceptable salts or prodrugs thereof, with other chemical components, or other components such as physiologically acceptable carriers and excipients. The purpose of a pharmaceutical composition is to facilitate administration of a drug to a living organism and promote absorption of the active ingredient, thereby exerting its biological activity.

[0055] An "effective amount" as described in this disclosure includes an amount sufficient to allow or facilitate diagnosis. An effective amount may be the maximum dosage or administration regimen that avoids significant side effects or toxic effects.

[0056] "Pharmaceutically acceptable excipient" includes, but is not limited to, any adjuvant, carrier, flow aid, sweetener, diluent, preservative, dye / colorant, flavor enhancer, surfactant, wetting agent, dispersing agent, suspending aid, stabilizer, isotonic agent, solvent, or emulsifier approved by the U.S. Food and Drug Administration for use in humans or domestic animals.

[0057] The term "antibody" encompasses various antibody structures, including, but not limited to, monoclonal antibodies, polyclonal antibodies, monospecific antibodies, multispecific antibodies (e.g., bispecific antibodies), full-length antibodies, and antibody fragments (or antigen-binding fragments or antigen-binding portions), as long as they exhibit the desired antigen-binding activity. Antibodies can refer to immunoglobulins, which have a tetrapeptide chain structure consisting of two identical heavy chains and two identical light chains connected by interchain disulfide bonds. The antigenicity differs due to differences in the amino acid composition and sequence of the immunoglobulin heavy chain constant region. Based on this, immunoglobulins may be divided into five classes, IgM, IgD, IgG, IgA, and IgE, where the corresponding heavy chains are μ, δ, γ, α, and ε chains, respectively, or are called immunoglobulin isotypes. Ig of the same class may be divided into different subclasses based on differences in the amino acid composition of the hinge region and the number and position of disulfide bonds in the heavy chains. For example, IgG may be divided into IgG1, IgG2, IgG3, and IgG4. Light chains are divided into kappa and lambda chains based on their constant region. Each of the five Ig classes can have either kappa or lambda chains. Approximately 110 amino acids near the N-terminus of an antibody's heavy and light chains are highly variable and comprise the variable region (V region), while the remaining amino acid sequences near the C-terminus are relatively stable and comprise the constant region (C region). The variable region contains three highly variable regions (HVRs) and four framework regions (FRs) with relatively conserved sequences. The three highly variable regions (HVRs) determine the antibody specificity and are also called complementarity-determining regions (CDRs). Each light chain variable region (VL) and heavy chain variable region (VH) consists of three CDR regions and four FR regions, arranged sequentially from the amino terminus to the carboxyl terminus in the order FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. The three CDR regions of the light chain are referred to as LCDR1, LCDR2 and LCDR3, and the three CDR regions of the heavy chain are referred to as HCDR1, HCDR2 and HCDR3.

[0058] The antibodies of the present disclosure may be polyclonal, monoclonal, xenogenic, allogeneic, isogenic, or modified forms thereof, with monoclonal antibodies being particularly applicable in several embodiments. Generally, the antibodies of the present disclosure are recombinant antibodies. As used herein, "recombinant" refers broadly to a product, such as a cell or polynucleotide, protein, or carrier, and indicates that the cell, polynucleotide, protein, or carrier has been modified by introducing a heterologous polynucleotide or protein or by altering a naturally occurring polynucleotide or protein, or that the cell is derived from a cell so modified. For example, recombinant cells express genes not present in the native (non-recombinant) cell form, or express naturally occurring genes that are normally aberrantly, underexpressed, or not expressed at all.

[0059] "Antigen-binding fragments" include single-chain antibodies (i.e., full-length heavy and light chains), Fab, modified Fab, Fab', modified Fab', F(ab')2, Fv, Fab-Fv, Fab-dsFv, single-domain antibodies (e.g., VH or VL or VHH), scFv, bivalent, trivalent, or tetravalent antibodies, Bis-scFv, diabody, tribody, triabody, tetrabody, and epitope-binding fragments of any of the above (see, e.g., Holliger and Hudson, 2005, Nature Biotech. 23(9):1126-1136; Adair and Lawson, 2005, Drug Design Reviews-Online 2(3), 209-217). Methods for generating and preparing these antigen-binding fragments are known in the art (see, e.g., Verma et al., 1998, Journal of Immunological Methods, 216, 165-181).

[0060] To determine or define CDRs, a definitive delineation of CDRs and identification of the residues comprising the antibody binding site can be completed by analyzing the structure of the antibody and / or the structure of the antibody-ligand complex. This can be accomplished by any of a variety of techniques known to those skilled in the art, such as X-ray crystallography. Various analytical methods can be used to identify CDRs, including, but not limited to, the Kabat numbering system, Chothia numbering system, AbM numbering system, IMGT numbering system, contact definition, conformational definition, etc.

[0061] The advantages and positive effects of the present disclosure are as follows: By binding gramine to platinum drugs, a novel gramine-platinum(IV) complex is synthesized, which shows superior biological activity compared to the parent cisplatin, and its IC 50 The α-glucan value is several tens of times lower than that of cisplatin, demonstrating excellent antiproliferative activity against various cancer cells, especially highly malignant triple-negative breast cancer cells, with significantly improved efficacy compared to clinical platinum compounds. Furthermore, the introduction of long fatty chains improves drug stability while simultaneously enhancing the lipid solubility and membrane permeability of the Pt(IV) molecule, facilitating platinum drug absorption. Gramine and di-aliphatic chain-substituted gramine-platinum(IV) complexes significantly improve drug stability and cellular uptake, enhancing antitumor activity while also reducing toxicity and achieving sustained release. The simple and inexpensive synthesis of the prodrug significantly improves the therapeutic efficacy of drug combination therapy. Compared to conventional divalent platinum and similar tetravalent platinum compounds, they offer advantages such as better therapeutic efficacy and fewer side effects, providing a new approach to tetravalent platinum modification. [Brief explanation of the drawings]

[0062] [Figure 1] FIG. 1 shows the intracellular release of compound c in Example 11. [Figure 2] FIG. 1 shows the changes in body weight of mice in different administration groups in Example 12 (**P<0.01, ***P<0.001). [Figure 3]FIG. 1 shows the changes in tumor volume in mice of different administration groups in Example 12 (**P<0.01, ***P<0.001). [Figure 4] FIG. 1 shows the final mouse tumor weights (**P<0.01, ***P<0.001) in Example 12. [Figure 5] FIG. 1 shows the survival rates of mice in different administration groups in Example 12. [Figure 6] FIG. 10 shows the distribution of final metallic platinum (Pt) in each structure in Example 12. [Figure 7] 10 is a final picture of the tumor in Example 12. [Figure 8] FIG. 1 shows the results of H&E staining of mouse organs and tumor tissues in Example 12. [Figure 9] FIG. 1 shows the results of immunohistochemical staining of mouse spleens in Example 12. [Figure 10] This figure shows the tumor volume change curves of mice in a pancreatic cancer PDX model (**P<0.01, ***P<0.001). [Figure 11] FIG. 1 shows tumor weights in mice in pancreatic cancer PDX models (**P<0.01, ***P<0.001). [Figure 12] Figure 1 shows the body weight change curves of mice in a pancreatic cancer PDX model (**P<0.01, ***P<0.001). [Figure 13] This figure shows the distribution of metallic platinum (Pt) in each tissue in a pancreatic cancer PDX model (**P<0.01, ***P<0.001). [Figure 14] FIG. 1 shows the volume change curves of mice in the pancreatic cancer KPC model (**P<0.01, ***P<0.001). [Figure 15] FIG. 1 shows tumor weights in mice in a pancreatic cancer KPC model (**P<0.01, ***P<0.001). [Figure 16] FIG. 1 shows the body weight change curves of mice in the pancreatic cancer KPC model (**P<0.01, ***P<0.001). DETAILED DESCRIPTION OF THE INVENTION

[0063] The present disclosure discloses a gramine-platinum(IV) complex in which one molecule of gramine is attached to one side of the axial direction of a tetravalent platinum coordination center to form a monosubstituted tetravalent platinum complex, the structure of which is shown in Formula 1-1: [ka] where: [ka] is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin or miriplatin, for example [ka] is cisplatin, oxaliplatin or carboplatin, and R1 is -C n H 2n -, n is an integer, n≧1, for example, n≦6 or n≦2, -C n H 2n When - is a straight chain group, the effect is better.

[0064] A novel gramine-platinum(IV) complex is synthesized by binding gramine to a platinum compound. Gramine is a natural indole alkaloid with various pharmacological activities, including anti-inflammatory, antitumor, antibacterial, and antioxidant properties. Gramine exerts antitumor effects by regulating various signaling pathways, and can significantly suppress tumor growth and metastasis by inhibiting the TGF-β signaling pathway, through mechanisms such as cell cycle inhibition, promotion of cell apoptosis, inhibition of tumor angiogenesis, inhibition of EMT occurrence, and inhibition of tumor invasion and metastasis. In some embodiments of the present disclosure, the compound may be represented by Structural Formula 2 or Structural Formula 3: [ka]

[0065] The method for preparing the gramine-platinum(IV) complex shown in the structure of Formula 1-1 is as follows.

[0066] Step 1: Acylation reaction of the gramine of formula 15 with the compound of formula 16 in the presence of a second condensing agent and a second acid scavenger to obtain the compound of formula 11; [ka] Here, the second condensing agent is DMAP, and the second acid scavenger is triethylamine.

[0067] Step 2: Esterification of the compound of formula 11 with the compound of formula 12 in the presence of a first condensing agent and a first acid scavenger to obtain a compound of formula 1-1; [ka] Here, the first condensing agent is TBTU, the first acid scavenger is triethylamine, the raw material ratio during the reaction is the compound of formula 11: the compound of formula 12: the first condensing agent: the first acid scavenger is 1-1.2:1:1.2-2:1.2-2, and the reaction is carried out under conditions of light shielding and inert gas protection.

[0068] The gramine-platinum(IV) complex of the present disclosure is in the form of a prodrug, capable of releasing the gramine ligand and the parent platinum compound intracellularly, aiming to achieve a synergistic sensitization effect while reducing the toxic side effects of the platinum compound. To improve the uptake and stability of Pt(IV), gramine is bound to one axial side of the tetravalent platinum coordination center, and aliphatic chains of different lengths are introduced to the other axial hydroxyl group of the platinum, resulting in a structure as shown in Formula 1-2: [ka] where: [ka] is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin or miriplatin, for example [ka] is cisplatin, oxaliplatin or carboplatin, and R1 is -C n H 2n -, n is an integer, n≧1, for example, n≦6 or n≦2, -C n H 2n When - is a straight chain group, the effect is better, and R2 is -C m H 2m+1 or -NH-C m H 2m+1 and m≧1, e.g., m≦20 or m≦17. In some embodiments, the gramine-platinum(IV) complex has 2≦m≦17, -C m H 2m+1 or -NH-C m H 2m+1 If is a straight chain group, the effect is better.

[0069] The introduction of long fatty chains improves drug stability, while at the same time increasing the lipid solubility and membrane permeability of the Pt(IV) molecule, promoting the absorption of platinum drugs. Gramine and fatty chain disubstituted gramine-platinum(IV) complexes significantly improve drug stability and cellular uptake, enhancing antitumor activity while also reducing toxicity and achieving sustained release. The simple and inexpensive synthesis of the prodrugs significantly improves the therapeutic efficacy of drug combination therapy, offering advantages such as better therapeutic efficacy and fewer side effects compared to conventional divalent platinum and similar tetravalent platinum preparations.

[0070] In some embodiments of the present disclosure, the compound may be represented by any of the structural formulas of Formulas 4 to 10: [ka]

[0071] The method for preparing the gramine-platinum(IV) complex shown in the structure of Formula 1-2 is as follows.

[0072] The compound of formula 1-1 is subjected to an esterification reaction with the compound of formula 13 or 14 to obtain a gramine-platinum(IV) complex represented by formula 1-2, [ka]

[0073] The gramine-platinum(IV) complex prepared above may be used to prepare antitumor drugs, for example, to treat breast cancer (e.g., triple-negative breast cancer), colorectal cancer, cervical cancer, head and neck cancer (e.g., pharyngeal squamous cell carcinoma), bladder cancer, ovarian cancer, pancreatic cancer, liver cancer, and lung cancer. The gramine-platinum(IV) complex exhibits superior biological activity compared to the parent cisplatin, and its IC 50 Its antiproliferative activity is several tens of times lower than that of cisplatin, and it has excellent antiproliferative activity against various cancer cells, especially highly malignant triple-negative breast cancer cells, and its efficacy is most significantly improved compared to clinical platinum agents.

[0074] The technical solutions of the present disclosure will be described below in conjunction with examples and drawings. However, these examples do not limit the scope of the present disclosure. All experimental methods for which the operation steps are not specifically described are carried out according to the instructions of the corresponding products. All instruments, reagents, and consumables used in the examples can be purchased from commercial companies unless otherwise specified.

[0075] Example 1: The structural formula of the gramine-platinum(IV) complex a3 in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Step 1: Gramine (2 g, 11.5 mmol) was accurately weighed and placed in a 50 mL round-bottom flask. 20 mL of dichloromethane was added. Succinic anhydride (2.30 g, 23 mmol), 4-dimethylaminopyridine (DMAP) (0.14 g, 1.15 mmol), and triethylamine (3.18 mL, 23 mmol) were added sequentially with stirring. The mixture was allowed to react overnight at room temperature. After TLC detection showed the reaction was complete, the solvent was removed by rotary evaporation. The solid was recrystallized from methanol to give compound a1 (2.74 g, 86.9% yield). After drying under vacuum, the solid was purified. Step 2: Cisplatin (1.00 g, 3.33 mmol) was accurately weighed and placed in a 25 mL round-bottom flask. 2 mL of distilled water was added and stirred. H2O2 (30% w / v, 10.0 mL) was slowly added dropwise and the mixture was incubated at 70 °C for 5 h in the dark. After the reaction was complete, the reaction mixture was cooled to room temperature and left at 4 °C overnight. The supernatant was removed by centrifugation to obtain a pale yellow solid. The solid was washed twice each with distilled water, ethanol, and ether, and then vacuum dried to obtain compound a2 (858.60 mg, 77.4% yield). Step 3: Compound A1 (100 mg, 0.36 mmol) was accurately weighed into a 10 mL round-bottom flask, 1 mL of ultra-dry DMSO was added, and TBTU (174 mg, 0.54 mmol) and TEA (75 μL, 0.54 mmol) were added with stirring. After 15 min, compound A2 (120 mg, 0.36 mmol) was added and the reaction was allowed to proceed overnight at room temperature, protected from light and under argon gas. TLC detection was performed when the reaction mixture became clear. The mixture was then poured into 20 mL of dichloromethane, sonicated, and centrifuged to collect the precipitate. The precipitate was washed with dichloromethane and methanol, respectively, and dried in a vacuum oven to yield compound A3 (91.76 mg, 43.2% yield) as a pale yellow solid. 1H NMR (400MHz, DMSO-d6): δ8.33 8.35(d, J=7.9Hz, 1H), 8.01(s, 1H), 7.80(d, J=7.3Hz, 1H), 7.45-7.29(m, 2H), 6.11 -5.78(m, 6H), 3.42(s, 2H), 3.26-3.14(m, 2H), 2.67(t, J=10.6Hz, 2H), 2.51(s, 6H). 13 C NMR (101MHz, DMSO-d6): δ179.37, 171.41, 135.08, 129.70, 125.02, 123.90, 123.38, 119.65, 118.76, 115.99, 54.90, 42.91, 31.43, 30.61. HR-MS(m / z): Calculated value C 15 H 24 Cl2N4O4Pt(M+H) + ,590.08223,Detected value:590.08990.

[0076] Example 2: The structural formula of the gramine-platinum(A) complex a in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound A3 (118.0 mg, 0.20 mmol) was accurately weighed into a 10 mL round-bottom flask, 2 mL of ultra-dry DMF was added, and hexyl isocyanate (50 μL) was added with magnetic stirring. The reaction was conducted overnight at 60 °C under argon gas protection and in the dark. After TLC detection showed the reaction was complete, the solvent was removed by rotary evaporation in a 60 °C water bath. The residue was dissolved in 1 mL of methanol and purified on a silica gel plate to give a white solid. The remaining DMF was removed by washing with anhydrous ether, and then dried under vacuum to give compound A (50.62 mg, 35.4% yield). 1H NMR (400MHz, DMSO-d6): δ8.33(d, J=8.0Hz, 1H), 7.80(s, 1H), 7.71(d, J=7.5Hz, 1H), 7.32(t, J=7.6Hz, 1H), 7.26(t, J=7.3Hz, 1H), 6.77(s, 6H), 6.53 (s, 1H), 3.54(s, 2H), 3.22-3.14(m, 2H), 2.88(d, J=5.5Hz, 2H), 2.72(t, J= 5.6Hz, 2H), 2.20(s, 6H), 1.34(s, 2H), 1.22(s, 6H), 0.85(t, J=6.6Hz, 3H). 13 C NMR (101MHz, DMSO-d6): δ179.67, 171.18, 164.01, 135.22, 130.30, 124.75, 124.51, 122.77, 11 9.82, 118.50, 115.88, 53.89, 45.05, 41.04, 31.15, 31.09, 29.85, 29.69, 26.08, 21.97, 13.73. HR-MS(m / z): Calculated value C 22 H 37 Cl2N5O5Pt(M+H) + ,717.18195,Detected value:717.18939.

[0077] Example 3: The structural formula of the gramine-platinum(A) complex b in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound a3 (118.0 mg, 0.20 mmol) was accurately weighed and placed in a 10 mL round-bottom flask. 2 mL of ultra-dry DMF was added. Octyl isocyanate (50 μL) was added with magnetic stirring. The reaction was conducted overnight at 60 °C under argon gas protection and in the dark. After TLC detection showed the reaction was complete, the solvent was removed by rotary evaporation in a 60 °C water bath. The residue was dissolved in 1 mL of methanol and purified on a silica gel plate to give a white solid. The remaining DMF was removed by washing with anhydrous ether, and the solid was then dried under vacuum to give compound b (54.68 mg, 36.7% yield). 1 H NMR (400MHz, DMSO-d6): δ8.33(d, J=8.1Hz, 1H), 7.79(s, 1H), 7.70(d, J=7.6Hz, 1H), 7.32(t, J=7.5Hz, 1H), 7.26(t, J=7.3Hz, 1H), 6.74(s, 6H), 6.53( s, 1H), 3.54(s, 2H), 3.22-3.12(m, 2H), 2.88(d, J=5.5Hz, 2H), 2.72(t, J=6 .1Hz, 2H), 2.20(s, 6H), 1.34(s, 2H), 1.23(s, 10H), 0.85(d, J=6.9Hz, 3H). 13 C NMR (101MHz, DMSO-d6): δ179.33, 171.18, 164.02, 135.56, 130.30, 124.64, 124.48, 123.08, 119.92, 1 18.96, 115.98, 53.91, 45.07, 40.92, 31.30, 31.14, 29.91, 29.81, 28.78, 28.70, 26.39, 22.08, 13.94. HR-MS(m / z): Calculated value C 24 H 41 Cl2N5O5Pt(M+H) + ,745.21325,Detected value:745.22064.

[0078] Example 4: The structural formula of the gramine-platinum(A) complex c in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound a3 (118.0 mg, 0.20 mmol) was accurately weighed and placed in a 10 mL round-bottom flask. 2 mL of ultra-dry DMF was added. Dodecyl isocyanate (50 μL) was added with magnetic stirring. The reaction was conducted overnight at 60 °C under argon gas protection and in the dark. After TLC detection showed the reaction was complete, the solvent was removed by rotary evaporation in a 60 °C water bath. The residue was dissolved in 1 mL of methanol and purified on a silica gel plate to give a white solid. The remaining DMF was removed by washing with anhydrous ether, and the solid was dried under vacuum to give compound c (49.02 mg, 30.6% yield). 1 H NMR (400MHz, DMSO-d6): δ8.33(d, J=8.1Hz, 1H), 7.78(s, 1H), 7.70(d, J=7.5Hz, 1H), 7.34-7.30(m, 1H), 7.26(t, J=7.4Hz, 1H), 6.68(s, 6H), 6.54(s, 1 H), 3.54(s, 2H), 3.17(t, J=6.4Hz, 2H), 2.88(d, J=6.0Hz, 2H), 2.73(t, J=6 .3Hz, 2H), 2.20(s, 6H), 1.33(s, 2H), 1.23(s, 18H), 0.84(d, J=6.9Hz, 3H). 13 C NMR (101MHz, DMSO-d6): δ179.39, 171.18, 163.76, 135.47, 130.13, 124.73, 124.55, 123.04, 120.00, 118.75, 116.04 , 53.87, 45.08, 41.02, 31.24, 31.08, 31.05, 29.82, 29.06, 29.03, 29.00, 28.88, 28.60, 26.44, 26.39, 22.07, 13.94. HR-MS(m / z): Calculated value C 28 H 49 Cl2N5O5Pt(M+H) + ,801.27585,Detected value:801.28473.

[0079] Example 5: The structural formula of the gramine-platinum(A) complex d in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound a3 (118.0 mg, 0.20 mmol) was accurately weighed into a 10 mL round-bottom flask, and 2 mL of ultra-dry DMF was added. Palmitic anhydride (200.1 mg, 0.40 mmol) was added with magnetic stirring. The mixture was then reacted overnight at 60 °C under argon gas protection and protected from light. After TLC detection showed the reaction was complete, the solvent was removed by rotary evaporation in a 60 °C water bath. The residue was dissolved in 1 mL of methanol and purified on a silica gel plate to give a white solid. The remaining DMF was removed by washing with anhydrous ether, and the solid was then dried under vacuum to give compound d (55.53 mg, 33.6% yield). 1 H NMR (400MHz, DMSO-d6): δ8.33 (d, J=8.1Hz, 1H), 7.81 (s, 1H), 7.72 (d, J=7.3Hz, 1H), 7.29 (dt, J=15.9, 7.3Hz, 2H), 6.54 (s, 6H), 3.60(s, 2H), 3.17(t, J=6.6Hz, 2H), 2.74(t, J=6.5Hz, 2H), 2.24(s, 6H), 1.33(d, J=81.8Hz, 28H), 0.85(s, 2H). 13 C NMR (101MHz, DMSO-d6): δ180.91, 179.51, 171.06, 135.47, 130.12, 124.78, 124.72, 123.08, 119.92, 118.30, 115.87, 53.66, 44 .85, 35.59, 31.22, 31.05, 30.99, 29.84, 29.09, 29.03, 28.99, 28.96, 28.90, 28.76, 28.68, 28.61, 25.46, 22.04, 21.09, 13.93. HR-MS(m / z): Calculated value C31 H 55 Cl2N4O5Pt(M+H) + ,828.31918,Detected value:828.31964.

[0080] Example 6: The structural formula of the gramine-platinum(IV) complex e3 of this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Step 1: Oxaliplatin (1.31 mg, 3.3 mmol) was accurately added to a round-bottom flask containing 2 mL of double-distilled water and 10 mL of 30% hydrogen peroxide. The mixture was heated to reflux at 70°C for 5 hours in the dark. After that, the heating was stopped, and the reaction mixture was allowed to return to room temperature. After that, the mixture was left in a refrigerator at 4°C overnight. The precipitate was collected by centrifugation, washed twice each with distilled water, absolute ethanol, and absolute ether, and then dried in vacuo to obtain compound e2 (0.87 g, 61.4% yield) as off-white crystals. Step 2: Compound A1 (63.4 mg, 0.23 mmol) was accurately weighed and dissolved in 1 mL of ultra-dry DMSO. TBTU (110.8 mg, 0.35 mmol) and TEA (48.3 μL, 0.35 mmol) were added sequentially. After stirring for 15 min, compound E2 (100 mg, 0.23 mmol) was added and the mixture was incubated overnight at room temperature under argon gas protection and protected from light. The reaction was monitored by TLC when the reaction mixture became clear. After completion of the reaction, an appropriate amount of dichloromethane was added to obtain a precipitate. The precipitate was then sonicated and centrifuged to recover the precipitate. The precipitate was washed with dichloromethane and methanol, respectively, and dried in a vacuum oven to obtain compound E3 (58.9 mg, 37.3% yield) as a pale yellow solid. 1H NMR (400MHz, DMSO-d6): δ8.38(s, 1H), 8.33(d, J=7.4Hz, 1H), 7.97-7.85(m, 2H) ), 7.85(d, J=6.8Hz, 1H), 7.46(s, 1H), 7.36(t, J=7.5Hz, 2H), 4.24(s, 2H), 3.2 6-3.18(m, 2H), 2.73-2.68(m, 2H), 2.67(s, 6H), 2.51-2.50(m, 2H), 2.05(d, J= 11.2Hz, 2H), 1.49(d, J=7.6Hz, 2H), 1.28-1.20(m, 1H), 1.12(t, J=16.8Hz, 3H). 13 C NMR (101MHz, DMSO-d6): δ180.50, 171.46, 163.94, 163.90, 135.05, 129.43, 125.06, 124.07, 123.4 4, 119.58, 115.72, 109.86, 61.24, 59.96, 51.09, 42.61, 31.34, 30.79, 30.73, 30.64, 23.64, 23.54. HR-MS(m / z): Calculated value C 23 H 32 N4O8Pt(M+H) + 688.19406, detected value: 688.19440.

[0081] Example 7: The structural formula of the gramine-platinum(A) complex e of this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound e3 (137.5 mg, 0.20 mmol) was accurately weighed and placed in a 10 mL round-bottom flask containing 2 mL of ultra-dry DMF. After complete dissolution, octyl isocyanate (50 μL) was added with stirring. The reaction was conducted overnight at 60 °C under argon gas protection and protected from light. After TLC detection, the reaction was complete. The solvent was removed by rotary evaporation and purified on a silica gel plate to obtain a white solid. After washing with anhydrous ether and drying under vacuum, compound e (52.6 mg, 31.2% yield) was obtained. 1 H NMR (400MHz, DMSO-d6): δ8.30(d, J=8.0Hz, 1H), 8.31-7.64(m, 4H), 7.79(s, 1H), 7.70(d, J=11.3Hz, 1H), 7.28(dt, J=18.5, 6.9Hz, 2H), 6.79(s, 1H), 3.5 4(s, 2H), 3.23(s, 2H), 2.97-2.84(m, 2H), 2.79-2.69(m, 2H), 2.21(s, 6H), 2 .11(s, 2H), 1.51(s, 2H), 1.33(s, 4H), 1.22(s, 14H), 0.85(t, J=6.7Hz, 3H). 13 C NMR (101MHz, DMSO-d6): δ179.42, 171.11, 164.44, 163.52, 163.31, 135.40, 130.16, 124.59, 124.47, 123.11, 120.00, 118.93, 115.6 7, 61.00, 60.62, 53.91, 45.05, 40.81, 31.25, 31.22, 31.08, 31.02, 29.61, 28.74, 28.69, 26.32, 26.26, 23.66, 23.35, 22.06, 13.91. HR-MS(m / z): Calculated value C 32 H 50 N5O9Pt(M+H) + 843.32508, Found value: 843.32526.

[0082] Example 8: The structural formula of the gramine-platinum(A) complex f in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound e3 (137.5 mg, 0.20 mmol) was accurately weighed and placed in a 10 mL round-bottom flask containing 2 mL of ultra-dry DMF. After complete dissolution, dodecyl isocyanate (50 μL) was added with stirring. The mixture was reacted overnight at 60 °C under argon gas protection and protected from light. After TLC detection, the reaction was complete. The solvent was removed by rotary evaporation and purified on a silica gel plate to give a white solid. After washing with anhydrous ether and drying under vacuum, compound f (52.7 mg, 29.3% yield) was obtained. 1 H NMR (400MHz, DMSO-d6): δ8.30(d, J=8.0Hz, 1H), 8.20(s, 1H), 7.71(d, J=7.7Hz , 1H), 7.65(s, 1H), 7.48(s, 1H), 7.28(dt, J=13.5, 7.7Hz, 2H), 7.11(s, 1H), 6.7 8(s, 1H), 3.54(s, 2H), 3.22(s, 2H), 2.94-2.83(m, 2H), 2.73(t, J=6.5Hz, 2H), 2 .20(s, 6H), 2.11(s, 2H), 1.50(s, 2H), 1.33(s, 4H), 1.23(s, 20H), 0.85(s, 3H). 13 C NMR (101MHz, DMSO-d6): δ179.43, 171.18, 164.37, 163.63, 163.42, 135.42, 130.19, 124.58, 124.48, 122.38, 118.93, 118.05, 115.73, 60.90, 6 0.51, 53.91, 45.09, 40.43, 31.27, 31.07, 30.95, 29.62, 29.05, 29.01, 28.98, 28.80, 28.73, 28.69, 26.29, 26.26, 23.63, 23.30, 22.06, 13.91. HR-MS(m / z): Calculated value C 36 H 58 N5O9Pt(M+H) +899.38768, Detected value: 899.38788.

[0083] Example 9: The structural formula of the gramine-platinum(A) complex g in this example is as follows: [ka] The method (synthetic route) for preparing the gramine-platinum(IV) complex described in this example is as follows: [ka] Compound e3 (137.5 mg, 0.20 mmol) was accurately weighed and placed in a 10 mL round-bottom flask containing 2 mL of ultra-dry DMF. After complete dissolution, palmitic anhydride (200.1 mg, 0.40 mmol) was added with stirring. The reaction was conducted overnight at 60 °C under argon gas protection and protected from light. After TLC detection, the reaction was complete. The solvent was removed by rotary evaporation and purified on a silica gel plate to give a white solid. After washing with anhydrous ether and drying under vacuum, compound g (53.3 mg, 28.9% yield) was obtained. 1 H NMR (400MHz, DMSO-d6): δ8.30(d, J=8.0Hz, 1H), 8.28(t, J=16.9Hz, 3H), 7.79(s, 1H), 7.71(d, J=7.5Hz, 1H), 7.32-7.23(m, 2H), 6.77(s, 1H), 3. 55(s, 2H), 2.94-2.84(m, 2H), 2.73(d, J=5.9Hz, 2H), 2.21(s, 6H), 2.11 (s, 2H), 1.51(s, 2H), 1.33(s, 4H), 1.23(s, 26H), 0.86(d, J=6.4Hz, 3H). 13C NMR (101MHz, DMSO-d6): δ179.49, 171.15, 164.38, 163.47, 135.40, 130.13, 124.58, 124.51, 123.10, 119.99, 118.83, 115.67, 60.75, 53.87, 4 5.01, 40.81, 31.41, 31.08, 30.93, 29.82, 29.79, 29.63, 29.58, 29.09, 29.06, 29.01, 28.80, 28.72, 28.67, 26.26, 23.71, 23.37, 22.10, 14.01. HR-MS(m / z): Calculated value C 40 H 66 N5O9Pt(M+H) + 926.41591, Detected value: 926.57.

[0084] Example 10: In vitro antitumor activity measurement The gramine-platinum (IV) complex prepared in the above example was subjected to in vitro antitumor activity measurement.

[0085] In this experiment, the antitumor activity of the synthesized compounds was investigated using the MTT (3-(4,5-dimethylthiazol-2)-2,5-diphenyltetrazolium bromide salt) method. Cytotoxicity experiments and studies were conducted using eight cancer cell lines: MDA-MB-231 (human breast cancer cells), MCF-7 (human breast cancer cells), HCT-116 (human colorectal cancer cells), HeLa (human cervical cancer cells), FaDu (human pharyngeal squamous cell carcinoma cells), 5637 (human bladder cancer cells), OVCAR3 (human ovarian cancer cells), HCCC9810 (human liver cancer cells), and normal human LO2 (human liver cells). All cell lines were cultured in an incubator with 5% CO2 concentration and saturated humidity at 37°C. The specific experimental steps are as follows:

[0086] After harvesting and counting the cells in the logarithmic growth phase, the cell concentration was adjusted to 3 x 10 4The solution was adjusted to cells / mL and inoculated into a 96-well plate at 100 μL per well to set up a blank (pure medium) and control (untreated) group. The plate was incubated overnight in a cell culture incubator. After adhesion to the wall, the compound was diluted with medium to the required concentration for the first column of wells, then diluted two-fold for subsequent wells and mixed uniformly by gentle pipetting. After 72 h of incubation, 10 μL (5 mg / mL) MTT solution was added to each well. After an additional 4 h of incubation in the incubator, the supernatant was removed, 100 μL / well of DMSO was added, and the wells were thoroughly shaken. The OD value was measured at λ = 570 nm using a microplate reader. To ensure the reliability of the experimental results, the experiment was independently repeated three times. [Table 1-1] [Table 1-2]

[0087] As shown in Table 1, the antiproliferative activity of the compounds against HeLa, MCF-7, MDA-MB-231, HCT-116, FaDu, 5637, OVCAR3, HCCC9810, and LO2 cells was detected, and the IC values ​​of compounds a to g were 50 The IC values ​​were significantly lower than those of cisplatin, oxaliplatin, gramin, and the combination administration, indicating superior antiproliferative ability against cancer cells. Compared to the structure of compound a3, compound c has an additional hydrophobic chain with 12 carbon atoms at the axial position, which resulted in IC values ​​in the cancer cell lines studied. 50 The IC values ​​ranged from 0.03 to 1.34 μM, and the antiproliferative activity of compound c was 225.29 times higher than that of cisplatin in the MDA-MB-231 cell line. Compound c also had relatively weak toxicity to LO2 cells, with a selectivity index of 13.14 for the tumor cell line MDA-MB-231 and the normal cell line LO2, while the selectivity index of cisplatin was 0.25 (the selectivity index is 0.25). 50 (LO2) / IC 50(defined as MDA-MB-231). As mentioned above, compound c has a highly efficient antitumor effect with low toxicity.

[0088] Example 11: Intracellular reduction experiments Investigating the intracellular release ability of prodrugs is crucial for studying the mechanism of action of tetravalent platinum, which must be reduced to divalent platinum in the body to function. To investigate whether the gramine-platinum(IV) complex can be reduced by reducing substances (such as glutathione or ascorbic acid) in cells to release divalent platinum and simultaneously exert the effect of sustained drug release, an intracellular reduction experiment was conducted. Taking compound c as an example, the specific experimental steps are as follows:

[0089] 1×10 6 MDA-MB-231 cells were seeded into a 6-well plate. After the cells adhered to the wells, 100 μM of compound c was applied to the cells and incubated for 4 h. The medium was discarded, the cells were washed three times with PBS, and then centrifuged to remove the PBS. The cells were resuspended in a fixed volume of methanol and dichloromethane and ground in a grinder for 10 min until the cells were completely dissolved. After grinding, the cells were left to stand for a certain period of time and then centrifuged to collect the supernatant. After the solvent was evaporated at room temperature, the solid was resuspended in 200 μL of methanol and detected in the liquid phase. The liquid-phase analysis conditions were ultraviolet (UV) detection wavelength 260 nm, mobile phase methanol and water (containing 0.1% formic acid), Venusil XBP C18 column (50 × 4.6 mm, 5 μm), high-performance liquid chromatography (LC-20A) manufactured by Shima Seiki Seisakusho, Japan, gradient elution, 5% to 95% methanol (0 to 10 min), 95% methanol for 25 min, flow rate 1 mL / min.

[0090] The HPLC detection results are shown in Figure 1. In the figure, the bands from bottom to top represent the untreated cell blank control, the intracellular extract sample of compound c, the compound c standard, the compound al (GM-COOH, gramine intermediate) standard, and the gramine (GM) standard, respectively. Three absorption peaks were observed from the bands in the intracellular extract sample of compound c. One peak had a peak time of 9.8 min, the same as that of the GM standard; another peak had a peak time of 10.7 min, the same as that of the GM-COOH standard; and the third peak had a peak time of 12.5 min, the same as that of the compound c standard, demonstrating that compound c can be released in vivo. Because the drug treatment time was only 4 h and the release of GM and GM-COOH was low, compound c was released further due to subsequent effects. As mentioned above, the gramine-platinum(IV) complex synthesized in this patent can be reduced intracellularly and has a sustained release effect.

[0091] Example 12: Study on the in vivo antitumor activity of drugs (breast cancer model) To investigate the antitumor effect of the gramine-platinum(IV) complex described in this disclosure, a study on the antitumor activity of the drug in vivo was carried out, and the specific steps are as follows:

[0092] First, 4T1-Luc tumor models were established using 4- to 5-week-old Balb / c female mice, with tumor volumes ranging from 50 to 100 cm. 3 After reaching a median age of 100, mice were randomly divided into four groups: PBS, CDDP, CDDP + GM, and compound c. The drug was administered at a concentration of 2.0 mg / kg Pt every three days. Mouse weights and tumor volumes were measured every two days for a total of six doses. The mice were then sacrificed, and organs (heart, liver, spleen, lungs, and kidneys) and tumors were extracted. The organs and tumors were then subjected to H&E staining, immunohistochemical staining, and platinum content measurement by ICP-MS.

[0093] The experimental results are shown in Figures 2 to 9. The tumor growth curve (Figure 3), tumor weight (Figure 4), and tumor final image (Figure 7) indicate that compound C significantly inhibited tumor growth compared to the blank group, and the inhibitory effect was significantly improved compared to the cisplatin and combination groups. Most importantly, the toxicity of compound C to mice was significantly reduced compared to the cisplatin and combination groups. As can be seen from the mouse weight change (Figure 2), the weight of mice in the compound C group remained stable and was not significantly different from that of the blank group, whereas the weight of mice in the cisplatin and combination groups showed a significant decrease. Analysis of the survival curve (Figure 5) indicates that the final survival rate of mice in the compound C group was 100%, while the final survival rate of mice in the cisplatin and combination groups was only 16.67% (including mice that died and mice whose body weight decreased to 20% of their original volume).

[0094] As can be seen from the ICP-MS results (Figure 6), compound c accumulation in the kidney and spleen was significantly reduced compared to cisplatin. Cisplatin's nephrotoxicity is one of its most severe toxicities. The low accumulation of compound c in the kidney effectively mitigated the toxic side effects of platinum-based drugs on the kidneys. H&E analysis revealed that both cisplatin and compound c caused severe damage to tumor tissue. However, compound c caused less damage to mouse organs, while cisplatin caused more severe damage to the spleen, kidney, and liver. This indicates that the toxicity of compound c was significantly reduced compared to cisplatin. Furthermore, immunohistochemistry results indicated that compound c could activate immune regulation and enhance antitumor immune responses. For example, the number of CD4+ and CD8+ cells increased, while the number of Treg cells (marked with Foxp3) decreased (Figure 9). The above in vivo antitumor experiments demonstrated that compound c had significantly improved antitumor activity and significantly reduced toxic side effects compared to cisplatin, tentatively achieving the therapeutic goal of enhancing the efficacy and reducing the toxicity of new antitumor drugs.

[0095] Example 13: In vitro pancreatic cancer cell proliferation inhibitory activity measurement In this experiment, the antitumor activity of the gramine-platinum(IV) complex and its ligands, cisplatin (CDDP), oxaliplatin (OXP), and compound c, was investigated using the CCK-8 (Cell Counting Kit-8) method. In this experiment, CCK-8 was used to study the proliferation activity of pancreatic cancer cells SU86.86, MIA-PaCa2, SW1990, CFPAC-1, and BxPC-3. All cell lines were cultured in a 5% CO2, 37°C, humidified incubator. The experimental steps were as follows:

[0096] After harvesting and counting the cells in the logarithmic growth phase, the cell concentration was adjusted to 3 x 10 4 The solution was adjusted to cells / mL and inoculated into a 96-well plate at 100 μL per well to set up a blank (blank, cell-free medium group) and a control (control, cell medium group). The cell culture plate was incubated overnight in a 37°C saturated humidity incubator. After the cells had adhered to the wall, the compound was diluted with medium to the required concentration in the first column of wells. A total of 18 concentration gradients were then administered using a 2-fold dilution method and gently pipetted to mix. After 72 h of incubation, 10 μL (5 mg / mL) of CCK8 solution was added to each well. After an additional 4 h of incubation in the incubator, the OD value was measured at λ = 450 nm using a microplate reader. [Table 2]

[0097] Example 14: In vitro organoid activity measurement Compound c and clinical bivalent platinum controls (cisplatin or oxaliplatin) were selected for in vitro organoid activity assays in two breast cancer organoid models and two pancreatic cancer organoid models. The experimental steps were as follows:

[0098] Tumor samples were collected from patients undergoing surgery for breast cancer and pancreatic cancer. Tumor samples were digested using a tumor isolation kit, tumor suspensions were collected, and tumor organoids were obtained by centrifugation. Complete culture medium for breast cancer or pancreatic cancer organoids was added to the organoid models, and the cells were cultured and passaged under 5% CO2, 37°C, and saturated humidity conditions. Organoids in the logarithmic growth phase were harvested and counted, and the organoid concentration was adjusted to 5 × 10 4 The cells were adjusted to cells / mL and resuspended in Matrigel. 20 μL of the solution was seeded into a 96-well plate, followed by the addition of 80 μL of complete medium. Blank (no organoid medium) and control (organoid medium-containing) groups were established. Organoids were cultured overnight in a 5% CO2, 37°C incubator. After the cells adhered to the wall, 200 μL of 20 μM drug-containing medium was added to the first treatment well. The drug was then dosed in a two-fold gradient and gently mixed by pipetting. After 96 hours of incubation, representative images of each well were taken using an inverted microscope. At the same time, 10 μL of CellTiter-Glo 3D Reagent (Promega) was added to each well to detect organoid vitality.

[0099] As can be seen from the detection results, compound c showed significant inhibitory effects in two breast cancer organoid models and two pancreatic cancer organoid models. IC of compound c in two breast cancer models 50 The IC values ​​were 0.6359 μM and 1.65 μM, respectively, and the IC values ​​in the two cases of pancreatic cancer were 50 However, in two breast cancer organoid models, the IC values ​​for the cisplatin control group were 4.967 μM and 3.993 μM, respectively. 50 All values ​​were greater than 20 μM, with one IC in the oxaliplatin control group in two pancreatic cancer organoid models. 50 Another example has an IC value of 12.65 μM. 50 The value is greater than 20 μM. As described above, compound c can exert an efficient antitumor effect in the organoid model, which is closer to tumor pathology.

[0100] Example 15: Study on in vivo antitumor activity (breast cancer PDX model) Patient-derived tumor tissue xenografts (PDXs) were used. Fresh tumor tissue from patients was processed and then implanted subcutaneously into the groin of immunodeficient NOD-SCID IL-2 receptor gamma null (NSG) mice. Relying on the microenvironment provided by the mice, these xenograft tumor models developed into tumor models with similar characteristics to the original tumor. Successfully implanted tumors were passaged in NSG mice for more than three generations. The mouse model was used for the experiment. Tumor volumes of 50–100 cm were used. 3 After reaching a median age of 100, mice were randomly divided into four groups: PBS, CDDP, OXP, and compound c. The drug was administered at a concentration of 3.0 mg / kg Pt every three days. Mouse weights and tumor volumes were measured every three days for a total of five doses. The mice were then sacrificed, and organs (heart, liver, spleen, lungs, and kidneys) and tumors were extracted. The organs and tumors were then used to measure platinum content by ICP-MS.

[0101] The results showed that the inhibitory effect of compound c was significantly improved compared to the solvent control group (PBS) and the positive control groups (cisplatin group and oxaliplatin group), using tumor growth as an indicator. The tumor inhibition rate of compound c at the treatment endpoint was 97.44%, while the tumor inhibition rates of the cisplatin and oxaliplatin groups were only 32.68% and 68.82%, respectively. At the same time, compound c also showed a significant toxicity reduction effect compared to the cisplatin and oxaliplatin groups (see tumor volume change curves in Figure 10 and tumor weight in Figure 11).

[0102] The mouse weight change curves (Figure 12) show that the mice in the compound c group began to show weight recovery and stabilization on the 9th day of treatment, which is thought to be due to compound c activating the body's immune protective mechanism, while the weight of the mice in the cisplatin and oxaliplatin groups showed a significant decrease throughout the treatment period.

[0103] In terms of survival rate, the final survival rate of mice in the compound c group was 100%, while the final survival rate of the cisplatin group was only 40%, and the survival rate of the oxaliplatin group was 60% (mice that died included mice that died and mice whose body weight decreased to 20% of their original volume).

[0104] Furthermore, as can be seen from the ICP-MS results in Figure 13, the accumulation of compound c in the kidneys and spleen was significantly lower than that of cisplatin. Cisplatin's nephrotoxicity is one of its most serious toxicities, and the low accumulation of compound c in the kidneys can effectively reduce the toxic side effects of platinum drugs on the kidneys. The above in vivo antitumor experiments demonstrated that compound c had significantly improved antitumor activity and significantly reduced toxic side effects compared to cisplatin and oxaliplatin in a pancreatic cancer model, confirming the broad-spectrum antitumor effect of compound c.

[0105] Example 16: Study on in vivo antitumor activity (pancreatic cancer KPC model) First, we established the KPC tumor model using 4- to 5-week-old C57BL / 6 female mice, with tumor volumes of 50 to 100 cm. 3 After reaching 100 mg / kg, mice were randomly divided into five groups: PBS, CDDP, OXP, compound c, and compound c + PD1 antibody (BioXcell BE0146-50MG InVivoMAb anti-mouse PD-1 (CD279)) combination group. The drug was administered at a concentration of 3.0 mg / kg Pt every three days. Mouse weights and tumor volumes were measured every three days for a total of five doses. Mice were sacrificed, and organs (heart, liver, spleen, lungs, and kidneys) and tumors were extracted. Tumors were used to measure immune cell content by flow cytometry.

[0106] The results showed that the inhibitory effect of compound c, measured by tumor growth, was significantly improved compared to the solvent control (PBS) and the positive control groups (cisplatin and oxaliplatin). The tumor inhibition rate for compound c at the treatment endpoint was 90.40%, compared to only 55.67% and 64.76% for the cisplatin and oxaliplatin groups, respectively. More importantly, the tumor inhibition rate for the compound c + PD1 antibody combination group was as high as 107.88%, demonstrating a clear trend toward tumor regression. At the same time, the compound c and compound c + PD1 antibody combination groups also showed significant toxicity reduction effects compared to the cisplatin and oxaliplatin groups (see tumor volume change curves in Figure 14 and tumor weight in Figure 15).

[0107] As can be seen from the mouse weight change curves (Figure 16), the weights of mice in the compound c and compound c + PD1 antibody combination groups remained stable and were not significantly different from the weights of mice in the solvent control group, whereas the weights of mice in the oxaliplatin-treated group showed a consistent tendency to decrease, and the weights of mice in the cisplatin-treated group decreased significantly.

[0108] In terms of survival rate, the final survival rates of mice in the compound c and compound c + PD1 antibody combination groups were all 100%, while all mice in the cisplatin group eventually died (the dead mice included mice that died and mice whose body weight decreased to 20% of their original volume).

[0109] After combined treatment with a PD-1 antibody, PD-1 levels in compound c alone were reduced to 9.24% compared to the vehicle control group (PD-1: 15.7%) and the positive control groups (cisplatin (PD-1: 24.3%) and oxaliplatin (PD-1: 21.0%), confirming that compound c alone can partially reverse the tumor's immunosuppressive microenvironment. More importantly, PD-1 levels in the PD-1 antibody combination group were significantly reduced to 1.96%, demonstrating that the pharmaceutical composition treatment regimen almost completely reversed the immunosuppressive effect of PD-1. These results collectively demonstrate that chemoimmunotherapy using an effective dose of gramine-platinum(IV) complex in combination with an immunomodulatory agent has significant antitumor activity against pancreatic cancer.

[0110] Although the embodiments of the present disclosure have been described in detail above, the described contents are merely preferred embodiments of the present disclosure and are not considered to limit the scope of the present disclosure. All equivalent modifications and improvements made based on the scope of the application of the present disclosure should be included within the patent scope of the present disclosure.

Claims

1. A gramine group is attached to one axial side of the tetravalent platinum coordination center, or a gramine group is attached to one axial side of the tetravalent platinum coordination center and an -NH- aliphatic chain group or an aliphatic chain group is attached to the other axial side; In particular, the structural formula is shown in Formula 1: 【Chemistry 1】 Here, R is a hydrogen atom, —C(O)—R ２ , deuterium atom or C １－６ is an alkyl group, 【Chemistry 2】 is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin, or miriplatin; Preferably, 【Transformation 3】 is cisplatin, oxaliplatin or carboplatin; R １ is -C ｎ H ２ｎ -, n is an integer, 1≦n≦6, preferably -C ｎ H ２ｎ - is a straight chain group, R ２ is -C ｍ H ２ｍ＋１ or -NH-C ｍ H ２ｍ＋１ wherein m is an integer, 1≦m≦20, and preferably, -C ｍ H ２ｍ＋１ or -NH-C ｍ H ２ｍ＋１ is a gramine-platinum(IV) complex characterized by a linear group.

2. The structural formula is shown in Formula 1-1 or Formula 1-2: 【Chemistry 4】 where: 【Transformation 5】 is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin, or miriplatin; Preferably, 【Transformation 6】 is cisplatin, oxaliplatin or carboplatin; R １ is -C ｎ H ２ｎ -, n is an integer, 1≦n≦6, preferably -C ｎ H ２ｎ - is a straight chain group, R ２ is -C ｍ H ２ｍ＋１ or -NH-C ｍ H ２ｍ＋１ wherein m is an integer, 1≦m≦20, and preferably, -C ｍ H ２ｍ＋１ or -NH-C ｍ H ２ｍ＋１ The gramine-platinum(IV) complex according to claim 1, wherein is a linear group.

3. -C ｎ H ２ｎ 3. The gramine-platinum(IV) complex according to claim 1, wherein - is a linear group and n is 1 or 2.

4. -C ｍ H ２ｍ＋１ or -NH-C ｍ H ２ｍ＋１ The gramine-platinum(IV) complex according to any one of claims 1 to 3, characterized in that m is a linear group and 6≦m≦17, preferably 6≦m≦15, more preferably m is 6, 8, 12 or 15.

5. Represented by any one of the structural formulas 2 to 10: 【Transformation 7】 The gramine-platinum(IV) complex according to any one of claims 1 to 4, wherein

6. The compound of formula 11 and the compound of formula 17 are subjected to an esterification reaction in the presence of a first condensing agent and a first acid scavenger to obtain a compound of formula 1, 【Transformation 8】 In particular, a compound of formula 11 and a compound of formula 12 are subjected to an esterification reaction in the presence of a first condensing agent and a first acid scavenger to obtain a compound of formula 1-1, 【Chemistry 9】 where: R is a hydrogen atom, —C(O)—R ２ , deuterium atom or C １－６ is an alkyl group, 【Chemistry 10】 is selected from cisplatin, oxaliplatin, carboplatin, heptaplatin, nedaplatin, lobaplatin, or miriplatin; Preferably, 【Chemistry 11】 is cisplatin, oxaliplatin or carboplatin; R １ is -C ｎ H ２ｎ -, n is an integer, 1≦n≦6, preferably -C ｎ H ２ｎ - is a straight chain group, In particular, the first condensing agent is TBTU, the first acid scavenger is triethylamine, and the raw material ratio during the reaction is 1-1.2:1:1.2-2:1.2-2, where: The method for preparing gramine-platinum(IV) complex according to any one of claims 1 to 5, further characterized in that the reaction is carried out under conditions of light protection and inert gas protection.

7. The compound of formula 1-1 is subjected to an esterification reaction with the compound of formula 13 or 14 to obtain a compound of formula 1-2, 【Chemistry 12】 where: m is an integer, 1≦m≦20, and preferably, -C ｍ H ２ｍ＋１ 7. The method for preparing a gramine-platinum(IV) complex according to claim 6, wherein is a linear group.

8. Gramine of formula 15 and the compound of formula 16 are subjected to an acylation reaction in the presence of a second condensing agent and a second acid scavenger to obtain a compound of formula 11, 【Chemistry 13】 7. The method for preparing gramine-platinum(IV) complex according to claim 6, wherein the second condensing agent is DMAP and the second acid scavenger is triethylamine.

9. The isotope-substituted compound of the gramine-platinum (IV) complex according to any one of claims 1 to 5, wherein the isotope-substituted compound is preferably a deuterated compound.

10. A pharmaceutical composition comprising at least one therapeutically effective amount of the gramine-platinum(IV) complex according to any one of claims 1 to 5 or the isotope-substituted compound according to claim 9, and a pharmaceutically acceptable excipient.

11. A pharmaceutical composition comprising the gramine-platinum(IV) complex according to any one of claims 1 to 5 or the isotope-substituted compound according to claim 9 and an immunosuppressant, and a pharmaceutically acceptable excipient. 【Request Item 12】 【Chemistry 14】 Here, R １ is -C ｎ H ２ｎ -, n is an integer, 1≦n≦6, preferably -C ｎ H ２ｎ - is a straight chain group, Furthermore, the compound of formula 11 is 【Chemistry 15】 or a pharmaceutically acceptable salt thereof.

13. Use of the gramine-platinum(IV) complex according to any one of claims 1 to 5, the pharmaceutical composition according to claim 10 or 11, or the compound of formula 11 or a pharmaceutically acceptable salt thereof according to claim 12 in the preparation of an antitumor drug.

14. 10. Use of the gramine-platinum(IV) complex according to any one of claims 1 to 5 or the isotope-substituted compound according to claim 9 in combination with an immunosuppressant in the preparation of an antitumor drug.

15. 15. The use according to claim 13 or 14, wherein the tumor is breast cancer, colorectal cancer, cervical cancer, head and neck cancer (such as pharyngeal squamous cell carcinoma), bladder cancer, ovarian cancer, pancreatic cancer, liver cancer or lung cancer.

16. the immunosuppressant is selected from an anti-PD-1 antibody or an antigen-binding fragment thereof, a PD-L1 antibody or an antigen-binding fragment thereof, or an anti-CTLA-4 antibody or an antigen-binding fragment thereof; The anti-PD-1 antibody or antigen-binding fragment thereof is preferably selected from the group consisting of pembrolizumab, nivolumab, camrelizumab, toripalimab, tislenizumab, cemiplimab, sintilimab, CS-1003, HLX-10, SCT-I10A, and sasanlim. ab, spartalizumab, MGD-013, retifanlimab, MEDI-0680, BAT-1306, MEDI-5752, LZM- 009, JTX-4014, BI-754091, AK-104, BCD-217, balstilimab, AK-103 or cetrelimab, The anti-PD-L1 antibody or antigen-binding fragment thereof is preferably Atezolizumab, Avelumab, Durvalumab, Adebrelimab, Envafolimab, CS-1001, TQB-2450, KL-A167, IMC-001, or CX-072; The pharmaceutical composition according to claim 11 or the use according to claim 14, wherein the anti-CTLA-4 antibody or antigen-binding fragment thereof is preferably ipilimumab or tremelimumab.

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