Preparation method of sulfur-containing cyclopeptide lipid drug and analogue thereof

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a novel preparation method of a sulfur-containing cyclopeptide lipid drug and analogues thereof. According to the method disclosed by the invention, a disulfide bond of a prodrug of a sulfur-containing cyclopeptide lipid natural product Romidepsin is subjected to structural modification to obtain a new analogue, and a new prodrug form of the Romidepsin is provided, so that the Romidepsin can better regulate and control release of corresponding mercaptan active molecules in vivo or cells so as to exert a drug effect, and the mercaptan active molecules are timely cleared in vivo, so that the curative effect of the Romidepsin is improved. Therefore, the cancer treatment effect is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis, and specifically relates to a novel preparation method of a sulfur-containing cyclic peptide lipid drug and its analogs. The method of the present invention structurally transforms the disulfide bond of the sulfur-containing cyclic peptide lipid natural product Romidepsin and its prodrug to obtain a new analog, and accordingly provides a new prodrug form of Romidepsin. Background Art

[0002] According to research data, cancer has become another major disease that endangers human health after cardiovascular and cerebrovascular diseases since its discovery. Statistics show that since the 1970s, the number of cancer cases and deaths in my country has been on the rise. It is estimated that by 2020, the annual number of tumor cases will reach 3 million, and the annual number of deaths will reach 2.5 million. Cancer has become the leading cause of death among urban residents in my country. Therefore, research and discovery of low-toxic and highly effective tumor treatment drugs have important social and commercial value.

[0003] The data records that many anti-tumor drugs have been developed internationally, and more than 80 anti-tumor drugs are commonly used in clinical practice. With the continuous deepening of tumor research in the industry, the development of new anti-tumor drugs is currently shifting from traditional cytotoxic drugs to specific anti-tumor drugs targeting abnormal signal system targets in cancer cells, that is, molecular targeted therapeutic drugs. With the continuous understanding of tumor signaling networks, reports show that some molecular targeted drugs have been developed in this field of technology and have entered clinical applications, achieving remarkable results. Among them, histone deacetylase (HDACs) is a protein that plays an important role in regulating tumor cell growth. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) are responsible for regulating the dynamic balance of core histone acetylation and deacetylation, thereby ensuring the normal function of human cells and preventing cancer. However, studies have confirmed that HDACs are overexpressed in most tumor cells, resulting in histone hypoacetylation. The imbalance of histone acetylation is closely related to the occurrence and development of tumors. It has also been found that HDACs inhibitors can achieve the purpose of treating cancer mainly through mechanisms such as blocking the cell cycle, inducing cell apoptosis, inhibiting angiogenesis, inducing autophagy, and exerting synergistic effects.

[0004] According to research, there are 18 subtypes of HDACs in mammalian cells, which are divided into the following four categories based on the homology with yeast HDAC sequences: Class I HDAC family includes HDAC1, HDAC2, HDAC3 and HDAC8, which are similar to yeast Rpd3 protein; Class II HDAC family includes HDAC4, HDAC5, HDAC6, HDAC7, HDAC9 and HDAC10, which are similar to yeast Hda1 protein; Class III HDAC family is similar to the sequence of yeast transcription repressor Sir2; Class IV has only one HDAC11. Among them, Class I, II and IV HDAC families are Zn2+ dependent targets, while Class III HDAC is a conserved nicotinamide adenine dinucleotide (NAD+) dependent target.

[0005] The literature records the HDACs inhibitors that have been discovered so far, which are mainly divided into the following types according to their structures: 1. Short-chain fatty acids, including butyric acid, phenylbutyric acid and isovaleric acid and their salts; 2. Hydroxamic acids, including trichostatin A (TSA) and vorinostat (SAHA) and their derivatives CBHA and MM232; 3. Cyclotetrapeptide structures without epoxy ketone groups, including FR90I228, apicidin and cyclotetrapeptide structures containing epoxy ketone groups, including trapoxin B; 4. Amides, including MS-275, CI-994 and cso55 (as shown below).

[0006]

[0007] The main HDACs inhibitor drugs currently in clinical use include: vorinostat (SAHA), which has high inhibitory activity against HDAC1, HDAC2, HDAC3, HDAC4, HDAC6, HDAC7, HDAC9 and HDAC10. The compound was approved by the US FDA in 2006 for the treatment of cutaneous T-lymphocytoma, and the similar hydroxamic acid HDACs inhibitor Belinostat was also approved for clinical use by the US FDA in 2014; cedaranid, an amide HDACs inhibitor, was approved for marketing in China in January 2015 for the treatment of peripheral T-cell lymphoma (PTCL); romidepsin (FK-228) belongs to the type I selective HDAC inhibitor, which has good selective inhibitory effect on HDAC type I, and it has good selective inhibitory effect on HDAC 2 and HDAC The inhibitory activity of 1 is stronger than that of HDAC4 and HDAC6. The disulfide bonds in its structure are reduced to sulfhydryl groups in the body and then play a role in binding metal ions. In 2010, it was approved by the US FDA for the clinical treatment of CTTL patients.

[0008] Romidepsin (FK228) is a natural product of sulfur-containing cyclic peptide lipid isolated from Chromobacterium violaceum. It belongs to the thiol cyclic peptide HDAC inhibitor and is a disulfide-containing prodrug. Romidepsin can be reduced by glutathione in cells, breaking disulfide bonds and releasing free thiol-containing active molecules (as shown below). The inhibitory activity of this molecule on HDACs can reach nanomolar levels. It mainly exerts anti-tumor effects by affecting the cell cycle, apoptosis and angiogenesis, but may cause adverse reactions such as cardiac toxicity, leukopenia, granulocytopenia and thrombocytopenia.

[0009]

[0010] Since Romidepsin is a prodrug, the release of the corresponding thiol active molecules in the body or cells can be regulated to exert its efficacy by changing its prodrug form, and it can be cleared in the body in time, thereby improving its effect of treating cancer. Based on the prior art, the inventors of the present application intend to provide a synthesis method of Romidepsin different from the existing one. The present invention intends to provide a new synthesis method of Romidepsin, especially a new preparation method of sulfur-containing cyclic peptide lipid drugs and analogs thereof. In the method, the disulfide bond of Romidepsin is structurally modified to obtain a new analogue, and a new prodrug form thereof is provided. Summary of the invention

[0011] The purpose of the present invention is to provide a new synthesis method of Romidepsin based on the prior art, especially a new preparation method of sulfur-containing cyclic peptide lipid drugs and analogs thereof. In this method, the disulfide bond of Romidepsin is structurally modified to obtain new analogs and provide new prodrug forms thereof.

[0012] Specifically, the present invention provides a method for preparing a compound represented by general formula (I):

[0013]

[0014] In the compound of general formula (I), A is a bridge connecting two sulfur atoms, which can be atom-free, i.e., two sulfur atoms are directly connected; or it can be a carbonyl or thiocarbonyl, i.e., two sulfur atoms are connected through a carbonyl or thiocarbonyl group;

[0015] The preparation method of the compound of the general formula (I) of the present invention is carried out according to the following synthetic route:

[0016]

[0017] These include the steps of:

[0018] first step

[0019] Compound 3 is generated from 2-ketobutyric acid 1 and benzyl carbamate 2 in the presence of an acid, under a suitable solvent and temperature; the acid is selected from CH3SO3H, p-toluenesulfonic acid or camphorsulfonic acid; the solvent is dichloromethane, chloroform or toluene; the reaction temperature is 0-120°C;

[0020] Step 2

[0021] Compound 3 generates compound 4 under suitable reagent and temperature; the reagent is selected from acetyl chloride, thionyl chloride or any combination thereof; the reaction temperature is 0-80°C;

[0022] Step 3

[0023] Compound 4 and cysteine ​​5 containing a protective group are condensed under the action of a base under the conditions of a suitable condensing agent, solvent and reaction temperature; then, under the action of a base, the compound 4 is aminolyzed with valine methyl ester hydrochloride 6 to prepare compound 7 in one pot; the condensing agent is selected from EDCI, DCC, HOAT, HOBT, HATU, PyBOP or DIC; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile, toluene, water or a combination thereof; the reaction temperature is 0-80°C;

[0024] Step 4

[0025] Compound 7 undergoes a deprotection reaction under the conditions of a suitable solvent and reaction temperature through the action of an acid to prepare a compound 8 containing a free amino group; the acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, trifluoroacetic acid, boron trifluoride etherate, or an acid generated in situ, such as acetyl chloride / methanol, acetyl chloride / ethanol, TMSCl / methanol, TMSCl / ethanol, TMSCl / isopropanol, TMSBr / methanol, TMSBr / ethanol, TMSI / methanol, TMSI / ethanol; the solvent is selected from water, methanol, ethanol, dichloromethane, THF, 1,4-dioxane, DMF, DMSO, acetonitrile or a combination thereof; the reaction temperature is 0-80°C;

[0026] Step 5

[0027] Compound 8 and valine 9 containing a protecting group undergo a condensation reaction under the conditions of a suitable condensing agent, a base, a solvent and a reaction temperature to prepare compound 10; the condensing agent is selected from EDCI, DCC, HOAT, HOBT, HATU, DIC or PyBOP; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from an organic solvent such as tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile, toluene, etc.; the reaction temperature is 0-80°C;

[0028] Step 6

[0029] Compound 10 undergoes a deprotection reaction under the conditions of a suitable solvent and reaction temperature through the action of an acid to prepare a compound 11 containing a free amino group; the acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, trifluoroacetic acid, boron trifluoride etherate, or an acid generated in situ, such as acetyl chloride / methanol, acetyl chloride / ethanol, TMSCl / methanol, TMSCl / ethanol, TMSCl / isopropanol, TMSBr / methanol, TMSBr / ethanol, TMSI / methanol, TMSI / ethanol; the solvent is selected from water, methanol, ethanol, dichloromethane, THF, 1,4-dioxane, DMF, DMSO, acetonitrile or a combination thereof; the reaction temperature is in the range of 0-80°C; Step 7

[0030] Compound 11 and chiral side chain 12 undergo aminolysis reaction under the action of a base in a suitable solvent and reaction temperature to generate compound 13; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile or toluene; the reaction temperature is 0-80°C;

[0031] Step 8

[0032] Compound 13 undergoes hydrolysis reaction under the action of a base under the conditions of a suitable solvent and reaction temperature to prepare compound 14; the base is selected from LiOH, NaOH, KOH, Bu3SnOH or Me3SnOH; the solvent is selected from water, tetrahydrofuran, methanol, ethanol, acetonitrile or a combination thereof; the reaction temperature is -10-80V;

[0033] Step 9

[0034] Compound 14 undergoes macrocyclic lactonization with configuration inversion in the presence of a suitable organic phosphine, an azo compound, an acid, a solvent and a temperature to obtain compound 15; wherein the organic phosphine is selected from Ph3P, (p-Tol)3P, Bu3P or Me3P; the azo compound is selected from DEAD or DIAD; the acid is selected from CH3SO3H, p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, N,N-dimethylformamide, acetonitrile or a combination thereof; and the temperature is 0-80°C.

[0035] Compound 15 undergoes a deprotection reaction and the formation of an intramolecular disulfide bond under the action of an oxidant in a suitable solvent and reaction temperature to prepare compound 16; the solvent is dichloromethane, 1,2-dichloroethane, THF, 1,4-dioxane, methanol, ethanol or acetonitrile; the reaction temperature range is 0-80°C; the oxidant is selected from I2, Br2, H2O2, DDQ, O2, PhIO or pyridine N-oxide;

[0036] Step 10

[0037] Compound 16 is subjected to the action of a reducing agent under the conditions of a base, a suitable solvent and a reaction temperature, and the disulfide bond of the compound 16 is broken to generate a dithiol compound; the reducing agent is selected from Ph3P, (p-Tol)3P, Bu3P or TCEP hydrochloride; the base is selected from potassium carbonate, sodium carbonate, sodium bicarbonate, DMAP, pyridine, Et3N, DIPEA, DBU or imidazole; the solvent is selected from toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, N,N-dimethylformamide, acetonitrile, methanol, ethanol, water or a combination thereof; the reaction temperature range is 0-80°C;

[0038] The prepared dithiol compound is subjected to the action of a carbonylation agent or a thiocarbonylation agent under the conditions of a suitable solvent and a reaction temperature to generate a dithiocarbonate or a dithiocarbonate thioester compound; the carbonylation agent or the thiocarbonylation agent is selected from phosgene (ClCOCl), triphosgene [(COCl2)3], triethylamine, DIPEA, pyridine, DMAP, imidazole, diimidazole carbonyl compound (Im-CO-Im), diimidazole thiocarbonyl compound (Im-CS-Im) or a combination thereof; the solvent is selected from toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, N,N-dimethylformamide, acetonitrile, methanol, ethanol, water or a combination thereof; and the reaction temperature range is 0-80°C.

[0039] The present invention provides a new preparation method of a sulfur-containing cyclic peptide lipid drug and its analogs. The method of the present invention structurally transforms the disulfide bond of the sulfur-containing cyclic peptide lipid natural product Romidepsin and its prodrug to obtain a new analog, and accordingly provides a new prodrug form of Romidepsin, so that it can better regulate the release of corresponding thiol active molecules in the body or cells to exert its efficacy, and clear it in the body in time, thereby improving its effect of treating cancer.

[0040] In the above description, the functional groups, chemical reagents or solvent codes are involved. With reference to the international general naming rules or common practices, the functional groups, chemical reagents or solvent codes are defined as follows: Ac: Acetyl;

[0041] Boc: tert-Butoxycarbonyl;

[0042] DIBALH: Diisobutylaluminium hydride;

[0043] DCE: Dichloromethane;

[0044] DCM: Dichloromethane;

[0045] DIPEA: Diisopropylethyamine;

[0046] DME: 1,2-Ethanedioldimethylether;

[0047] DMAP: 4-Dimethylaminopyridine;

[0048] DMF: N,N-Dimethylformamide;

[0049] DMP: Dess-Martin periodinane;

[0050] DMSO: Dimethylsulfoxide;

[0051] DPPA: Diphenylphosphonic acid;

[0052] DMPU: 1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone;

[0053] DDQ:2,3-Dichloro-5,6-dicyanobenzoquinone

[0054] EA:EthylAcetate;

[0055] EDCI:Dimethylaminopropyl-N’-enthylcarbodiimide hydrochloride;

[0056] Fmoc:9-Fluorenylmethylformyl;

[0057] HATU:2-(7-Aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumHexafluorophosphate;

[0058] HOAT:1-Hydroxy-7-azabenzotriazole;

[0059] HOBT:1-Hydroxybenzotriazole;

[0060] LDA:Lithium diisopropylamide;

[0061] MeCN:Acetonitrile;

[0062] NaHMDS:Sodiumbis(trimethylsilyl)amide;

[0063] PE:Petroleum ether

[0064] Py:Pridine;

[0065] THF:Tetrahydrofuran;

[0066] TIPS:Triisopropylsilane;

[0067] TFA:Trifluoroacetic acid;

[0068] TMSOTf:Trimethylsilyltrifluoromethanesulfonate;

[0069] Tol:Toluene;

[0070] TMSCl:Me3SiCl;

[0071] TMSBr:Me3SiI;

[0072] TMSI:Me3SiI;

[0073] Trt:Ph3C-;

[0074] TSE:-OCH2CH2SiMe3

[0075] OTSE:-OCH2CH2SiMe3 DETAILED DESCRIPTION

[0076] The present invention is further described below with reference to examples, but these examples are not intended to limit the scope of the present invention.

[0077] Example 1 Synthesis of romidepsin and its analogs

[0078] According to the following synthetic route and steps:

[0079]

[0080] Step 1: Preparation of compound 3

[0081]

[0082] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, add the raw materials 2-ketobutyric acid 1 (0.204 g, 2.0 mmol) and benzyl carbamate 2 (0.333 g, 2.2 mmol), add a trace amount of p-toluenesulfonic acid (10 mg), dissolve in 5.0 mL of anhydrous toluene, heat to reflux, separate water with a water separator, and react for 6 hours. Cool the reaction solution, wash with saturated NaHCO3 (aq) (30 mL × 3), adjust the pH to 1-2 with dilute hydrochloric acid, collect the precipitate and recrystallize with 8 mL of toluene to obtain crude product 3 (R f =0.65, DCM / MeOH=10 / 1), an orange-yellow solid.

[0083] 1 HNMR (600MHz, CDCl3) δ77.37(m,5H),6.91(q,J=7.2Hz,1H),6.22(s,1H),5.16(s,2H),1.85(d,J=7.3Hz,3H).ESI-MS(m / z): 258.0[M+Na]+.

[0084] Step 2: Preparation of compound 4

[0085]

[0086] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, compound 3 (0.170 g, 0.72 mmol), 1.0 mL acetyl chloride and 3.0 mL thionyl chloride were added, and the mixture was reacted at room temperature for 2 h. The mixture was concentrated under reduced pressure to remove acetyl chloride and thionyl chloride, dissolved in 2 mL carbon tetrachloride, concentrated to remove the solvent, and repeated three times. The mixture was recrystallized from cyclohexane to obtain 0.079 g of a yellow solid 4 (Rf = 0.20, PE / EA = 6 / 1), with a two-step yield of 87%.

[0087] 1 H NMR (400MHz, CDCl3) δ8.67(brs,1H),8.11(brs),6.12(m,1H),5.92(m),2.21(d,J=5.0Hz ),1.91(d,J=4.8Hz,3H).ESI-MS(m / z):128.0[M+H]+.HRMS-ESI(m / z):[M+H]+Calcd.For C5H5NO3: 128.0342, found: 128.0330.

[0088] Step 3: Preparation of compound 7

[0089]

[0090] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, add compound 5 (0.509 g, 1.1 mmol) and compound 4 (0.127 g, 1.0 mmol), dissolve in 5.0 mL of anhydrous THF, heat the solution to 40 ° C, add DIC (0.208 g, 1.65 mmol) and trace pyridine (0.05 mL), and react overnight. Monitor the reaction by thin layer TLC until the raw material 4 basically disappears, take another clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, add L-valine methyl ester hydrochloride (compound 6, 0.168 g, 1.0 mmol), dissolve in 5 mL of anhydrous DCM until the solution is clear, add 0.34 mL of triethylamine, stir for 0.5 h, and the solution becomes white and turbid. Use a long needle to transfer the above solution to the reaction solution of compounds 5 and 4 and react overnight. The reaction solution was concentrated, dissolved with a large amount of DCM, quenched with saturated NaHCO3 (aq), extracted with DCM three times (30 mL×3), washed with saturated brine, dried over granular anhydrous sodium sulfate, filtered and dried, the filtrate was concentrated, and purified by column chromatography on a silica gel column (eluent ratio: PE / EA=2 / 1-1 / 1) to give 0.169 g of white foamy solid 7 (Rf=0.35, PE / EA=1 / 1), with a yield of 26%.

[0091] [α] 20 D :-1.5(c=1.0CHCl3).1 H NMR (400MHz, CDCl3) δ7.46–7.21(m,28H),6.76(m,2H),4.77(m,1H),4.46(m,1H),3.70(m,1H),3.67(s,3H),2.76(d d,J=12.9,7.0Hz,1H),2.68(dd,J=12.9,5.8Hz,1H),2.08(m,1H),1.69(d,J=6.9Hz,3H),1.42(s,9H),0.89(m,6H). 13 C NMR (150MHz, CDCl3) δ172.33,169.64,163.97,155.79,144.18,132.35,129.56,128.68,128.16,127.03,8 0.93,67.51,57.93,54.15,51.95,33.87,30.91,28.23,19.06,18.24,13.47.ESI-MS(m / z): 682.2[M+Na]+.

[0092] Step 4: Preparation of compound 8

[0093]

[0094] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, compound 7 (0.169 g, 0.256 mmol) was added and dissolved in 5 mL of anhydrous DCM. In another clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, boron trifluoride etherate (0.07 mL, 0.513 mmol) was dissolved in 7 mL of anhydrous DCM. The reaction solution of compound 7 was cooled to 0°C, and a DCM solution of boron trifluoride etherate was added dropwise, and the reaction was carried out at room temperature for 5 h. At 0°C, the reaction solution was quenched with saturated NaHCO3 (aq), and the reaction solution was extracted three times with DCM (10 mL×3). The organic phases were combined, washed with saturated brine, dried with granular anhydrous sodium sulfate, filtered, and the dried solution was concentrated. The filtrate was purified by column chromatography on a silica gel column (eluent ratio: EA) to obtain 0.103 g of a white foam solid 8 (Rf=0.35, DCM / MeOH=30 / 1), with a yield of 72%.

[0095] [α] 20 D :85.7(c=1.0CHCl3). 1H NMR (400MHz, CDCl3) δ8.53(brs,1H),7.46(m,6H),7.33–7.20(m,12H),6.61(brd,1H),6.55–6.49(m,1H),4.52(dd,J=8.0 ,4.7Hz,1H),3.71(s,3H),3.18(m,1H),2.89–2.61(m,2H),2.11(m,1H),1.68(d,J=7.1Hz,3H),1.63(m,2H),0.89(m,6H). 13 C NMR (150MHz,CDCl3)δ

[0096] 172.32,171.96,144.47,129.60,129.12,128.03,126.88,67.22,57.45,5 3.98,52.12,36.93,31.37,18.94,17.96,13.66.ESI-MS(m / z):558.2[M+H] + .

[0097] Step 5: Preparation of compound 10

[0098]

[0099] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, compound 8 (0.075 g, 0.134 mmol), Boc-D-valine (compound 9, 0.029 mg, 0.134 mmol) and PyBOP (0.139 mg, 0.268 mmol) were added, dissolved in 5 mL of anhydrous DCM, and stirred for 10 min. DIPEA 0.07 mL was slowly added dropwise and stirred at room temperature for 2 h. After the reaction was basically completed by TLC monitoring, saturated ammonium chloride solution was added to quench the reaction solution, and the reaction solution was extracted three times with DCM (10 mL × 3), the organic phases were combined, washed with water, washed with saturated brine, dried with granular anhydrous sodium sulfate, filtered, and concentrated to obtain crude product 10 (Rf = 0.30, PE / EA = 2 / 1) 0.099 g, a white foamy solid. ESI-MS (m / z): 781.2 [M + Na] +.

[0100] Step 6: Preparation of compound 11

[0101]

[0102] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, add compound 10 (0.069 g, 0.091 mmol) and dissolve it with 3 mL of anhydrous DCM. In another clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, dissolve boron trifluoride etherate (0.03 mL, 0.182 mmol) with 5 mL of anhydrous DCM. Cool the reaction solution of compound 10 to 0°C, add the DCM solution of boron trifluoride etherate dropwise, and react at room temperature for 5 h. At 0°C, quenched with saturated NaHCO3 (aq), the reaction solution was extracted three times with DCM (10 mL×3), the organic phases were combined, washed with water, washed with saturated brine, added with granular anhydrous sodium sulfate, dried, filtered and dried, the filtrate was concentrated, and purified by column chromatography on a silica gel column (eluent ratio: DCM / MeOH=30 / 1) to give a white foamy solid 11 (Rf=0.25, DCM / MeOH=30 / 1) 0.037 g, yield 62%.

[0103] [α] 20 D :4.8(c=1.0CHCl3). 1 H NMR (400MHz, CDCl3) δ7.80(d,J=6.8Hz,1H),7.48–7.19(m,18H),6.74(q,J=7.4Hz,1H),6.65(d,J=8.7Hz,1H),5.31(m,1H),4 .56–4.45(m,1H),3.67(s,3H),3.26(m,1H),2.80(dd,J=13.0,6.2Hz,1H),2.63(dd,J=13.0,6.2Hz,1H),2.21(m,1H),2.10(m 1H),1.67(d,J=6.8Hz,3H),0.96(d,J=6.8Hz,3H),0.93–0.86(m,6H),0.79(d,J=6.8Hz,3H). 13 C NMR (150MHz, CDCl3) δ175.94,172.53,168.79,163.73,144.31,132.33,129.55,128.41,128.10,126.94,67.32,59. 89,57.62,53.42,52.83,51.96,32.12,31.23,30.76,19.55,18.92,18.20,16.31,13.69.ESI-MS(m / z): 681.2[M+Na] + .

[0104] Step 7: Preparation of compound 13

[0105]

[0106] In a clean, dry 100 mL eggplant-shaped reaction bottle protected by argon, compound 11 (1.318 g, 2.0 mmol) was added, dissolved with 30 mL of anhydrous DCM, dissolved by stirring at room temperature, and DMAP (0.635 g, 5.2 mmol) was added. In another clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, compound 12 was dissolved with 10 mL of anhydrous DCM, and added dropwise to the reaction solution of compound 11, and the reaction was heated at 40°C overnight. The reaction solution was quenched with saturated ammonium chloride solution, and the reaction solution was extracted three times with DCM (50 mL×3), the organic phases were combined, washed with water, washed with saturated brine, dried with granular anhydrous sodium sulfate, filtered, and concentrated. Purification was performed on a silica gel column by column chromatography (eluent ratio: PE / EA=2 / 1-1 / 1) to obtain 0.932 g of white foamy solid 13 (Rf=0.22, PE / EA=2 / 1), with a yield of 44%.

[0107] [α] 20 D :2.7(c=1.0CHCl3). 1 H NMR(600MHz, CDCl3)δ7.79(d,J=20.9Hz,1H),7.40(m,16H),7.32–7.17(m,26H),6.97–6.83(m,2H),6.78(d, J=8.5Hz,1H),6.65(m,1H),5.49(dt,J=14.1,6.7Hz,1H),5.35(dd,J=15.3,6.7Hz,1H),4.46(dd,J=8.6,6.0 Hz,1H),4.33(s,1H),4.17(t,J=6.4Hz,1H),4.14–4.09(m,1H),3.67(brd,1H),3.64(s,3H),2.75(dd,J=12. 8,7.0Hz,1H),2.64(dd,J=12.8,5.8Hz,1H),2.37(dd,J=15.2,3.2Hz,1H),2.29(dd,J=15.2,9.0Hz,1H),2.22

[0108] –2.03(m,9H),1.65(d,J=7..2Hz,3H),0.87(m,12H). 13C NMR (150MHz, CDCl3) δ171.65,171.55,170.67,167.95,163.22,143.82,143.16,131.28, 131.21,129.21,128.54,128.46,127.76,127.12,126.86,125.97,125.62,68.34,66.27 ,65.58,58.18,56.86,51.88,50.99,41.91,31.86,30.41,30.29,30.05,29.15,28.66,1 8.41,18.01,17.30,16.79,12.52.ESI-MS(m / z):1081.0[M+Na]+.HRMS-ESI(m / z):[M+Na] + Calcd.ForC63H70N4O7S2: 1081.4578, found: 1081.4592.

[0109] Step 8: Preparation of compound 14

[0110]

[0111] In a clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, compound 13 (0.741 g, 0.699 mmol) was added, dissolved with 11 mL of anhydrous THF, and 5 mL of 1M LiOH aqueous solution was added dropwise under an ice-salt bath, reacted for 1 h under an ice-salt bath, removed the ice-salt bath and naturally warmed to room temperature, and continued to react for 1 h before stopping the reaction. 1M HCl was added dropwise to adjust the pH of the solution to 3, and the reaction solution was extracted three times with EA (150 mL×3), the organic phases were combined, dried with powdered anhydrous magnesium sulfate, the dried solution was filtered, the filtrate was concentrated, and purified by column chromatography on a silica gel column (eluent ratio: DCM / MeOH=20 / 1-10 / 1) to obtain 0.614 g of a light yellow foam solid 14 (Rf=0.35, DCM / MeOH=20 / 1), with a yield of 84%.

[0112] [α] 20 D :12.2(c=1.1CHCl3). 1H NMR(600MHz, CDCl3)δ7.94(brs,1H),7.44–7.16(m,37H),7.06–6.98(m,2H),6.77( m,1H),5.48(dt,J=14.4,6.7Hz,1H),5.33(dd,J=15.2,6.7Hz,1H),4.32(m,1H),4.2 3(m,1H),4.05(t,J=5.8Hz,1H),3.96(m,1H),2.84–2.75(m,1H),2.66–2.58(m,1H) ,2.36–2.27(m,2H),2.18(m,3H),2.04(m,3H),1.66(d,J=7.2Hz,3H),0.89(m,12H). 13 C NMR (150MHz, CDCl3) δ173.13,172.06,169.15,164.98,144.83,144.15,134.05,132.07,130.58,129.57,129.46,128.16,127.89,127.02,126.6 5,69.38,67.31,66.63,59.73,53.20,42.95,32.69,31.41,31.28,30.06 ,29.95,19.39,19.20,18.47,17.97,13.61.ESI-MS(m / z): 1081.0[M+Na] + .HRMS-ESI(m / z): [M+Na] + Calcd.ForC62H68N4O7S2: 1067.4422, found: 1067.4421.

[0113] Step 9: Preparation of compound 16

[0114]

[0115] In a clean, dry 500 mL eggplant-shaped reaction bottle protected by argon, triphenylphosphine (1.311 g, 5 mmol) was added, dissolved in 200 mL of anhydrous THF, p-toluenesulfonic acid (0.172 g, 1 mmol) and DIAD (0.81 mL, 4 mmol) were added, and stirred at room temperature for 20 min until completely dissolved. The solution gradually changed from yellow to colorless, and the solution was cooled to 0°C in an ice-salt bath. In another clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, compound 14 (0.209 g, 0.2 mmol) was added, dissolved in 20 mL of anhydrous THF, and slowly added dropwise to the above solution for 2 h, and the reaction was continued at 0°C for 2 h. The reaction solution was concentrated and purified by column chromatography on a silica gel column to remove the triphenylphosphine impurity with low polarity (eluent ratio: PE / EA=1 / 1-DCM / MeOH=10 / 1) to obtain crude product 15.

[0116] In a clean, dry 100 mL eggplant-shaped reaction bottle protected by argon, iodine (0.158 g, 0.62 mmol) was dissolved in 30 mL of anhydrous DCM and 5 mL of anhydrous methanol, and stirred in an ice-salt bath for 10 min. In another clean, dry 50 mL eggplant-shaped reaction bottle protected by argon, the crude product was dissolved in 5 mL of anhydrous DCM, and slowly added dropwise to the iodine solution under vigorous stirring, and reacted for 20 min. 15 mL of 10% Na2S2O3 solution was added to quench the reaction solution, and the reaction solution was extracted three times with DCM (30 mL×1). The organic phases were combined, washed with saturated NaHCO3(aq) (60 mL×1), and then washed with saturated NaCl solution (60 mL×1), added with powdered anhydrous magnesium sulfate, dried, filtered and dried, concentrated the filtrate, and purified by column chromatography on a silica gel column (eluent ratio: PE / EA=1 / 2.5) to obtain 0.012 g of compound 16 (Rf=0.22, PE / EA=1 / 2.5), with a yield of 11%.

[0117] [α] 20 D :44.3(c=1.1CHCl3). 1H NMR(600MHz, CDCl3)δ8.26(brs,1H),7.74(d,J=6.5Hz,1H),7.26(m,2H),6.52(m,1H),6.36(q, J=7.1Hz,1H),5.84–5.68(m,3H),4.77(dt,J=11.6,2.4Hz,1H),4.71(dd,J=7.2,2.4Hz,1H),4. 08(m,1H),3.24(m,1H),3.20–3.10(m,2H),3.04–2.93(m,1H),2.84(m,1H),2.66(m,3H),2.41( m,1H),2.24(m,1H),1.74(d,J=7Hz,3H),1.11(m,6H),1.02(d,J=7Hz,3H),0.99(d,J=7Hz,3H). 13 C NMR (150MHz, CDCl3) δ172.07,170.11,169.20,168.53,164.85,131.31,130.34,129.82,128.82,69.54,62.21,58. 04,56.04,38.64,38.09,34.12,32.27,30.50,29.25,19.66,19.55,18.52,18.42,13.21.ESI-MS(m / z): 541.2[M+H] + .

[0118] Step 10: Preparation of compound 17

[0119]

[0120] In a clean, dry 100 mL eggplant-shaped reaction bottle protected by argon, compound 16 (0.100 g, 0.185 mmol), TCEP hydrochloride (0.080 g, 0.278 mmol) and potassium carbonate (0.077 g, 0.555 mmol) were added, dissolved with 18 mL DCM and 18 mL water, and reacted at room temperature for 2 h. The reaction was monitored by thin layer TLC until compound 16 disappeared, then the liquid was separated, the aqueous phase was extracted three times with DCM (30 mL × 3), the organic phases were combined, and granular anhydrous sodium sulfate was added to dry. The dried liquid was filtered, diluted with 80 mL of anhydrous DCM, and CDI (Im-CO-Im, diimidazole carbonyl compound, 0.036 g, 0.222 mmol) was added thereto, and reacted at room temperature for 3 h under light-proof conditions. The product was washed with water and saturated brine, dried over granular anhydrous sodium sulfate, the dried liquid was filtered, the filtrate was concentrated, and purified by column chromatography on a silica gel column (eluent ratio: DCM / MeOH=20 / 1), silica gel thin layer chromatography (elution ratio: DCM / MeOH=30 / 1) to give a white solid product 17 (A:C=O), Rf=0.5, DCM / MeOH=20 / 1) 0.018 g, with a yield of 18%.

[0121] δ 1 HNMR(600MHz, CDCl3)δ8.02(brs,1H),7.60(d,J=7.0Hz,1H),7.37(d,

[0122] J=7.1Hz,1H),6.70(q,J=7.1Hz,1H),6.53(m,1H),6.00(dd,J=16.2,7.8Hz,1H),5.60(dt,J=13.2,7.8Hz,1H),5. 51–5.44(m,1H),5.13(m,1H),4.51(m,1H),3.97(m,1H),3.73(t,J=12.5Hz,1H),3.49(dd,J=14.6,4.4Hz,1H),3.3 9(dd,J=14.6,2.4Hz,1H),3.02(dd,J=15.7,3.8Hz,1H),2.72(dd,J=13.5,7.4Hz,1H),2.61(m,1H),2.56(m,1H), 2.47(m,1H),2.39(m,1H),2.33(m,2H),1.71(d,J=7Hz,3H),1.18(m,6H),1.06(d,J=7Hz,3H),0.92(d,J=7Hz,3H). 13C NMR (150MHz, CDCl3) δ194.66,170.79,170.38,166.91,166.68,163.27,133.07,132.06,127.87,123.65,70.30,62.37, 57.94,52.32,39.11,31.27,30.99,29.29,28.61,25.37,18.14,18.07,17.83,16.32,12.88.ESI-MS(m / z): 569.0[M+H] + .HRMS-ESI(m / z): [M+Na] + Calcd.For C25H36N4O7S2: 569.2098, found: 569.1910.

[0123] Alternatively, in a clean, dry 100 mL eggplant-shaped reaction bottle protected by argon, compound 16 (0.100 g, 0.185 mmol), TCEP hydrochloride (0.080 g, 0.278 mmol) and potassium carbonate (0.077 g, 0.555 mmol) were added, dissolved with 18 mL DCM and 18 mL water, and reacted at room temperature for 2 h. The reaction was monitored by thin layer TLC until compound 16 disappeared, and then the liquid was separated, and the aqueous phase was extracted three times with DCM (30 mL×3), the organic phases were combined, dried with granular anhydrous sodium sulfate, filtered, and diluted with 80 mL of anhydrous DCM, and TCDI (Im-CS-Im, diimidazole thiocarbonyl compound, 0.040 g, 0.222 mmol) was added thereto, and the reaction was carried out at room temperature overnight under light-proof conditions. The mixture was washed with water and saturated brine, dried over granular anhydrous sodium sulfate, the dried liquid was filtered, the filtrate was concentrated, and purified by column chromatography on a silica gel column (eluent ratio: DCM / MeOH=45 / 1) and silica gel thin layer chromatography (eluent ratio: DCM / MeOH=50 / 1) to give a white solid product 17 (A:C=S) (Rf=0.24, DCM / MeOH=50 / 1) 0.032 g, with a yield of 32%.

[0124] 1HNMR(400MHz,CDCl3)δ8.16(brs,1H),7.38(m,1H),7.30–7.20(m,1H),6.71–6.54(m,2H),5.91(m,1H),5.60(m,2H),5.13(m,1H),4.58(m,1H),4.28(m,1H),3.91(m,1H),3.69(m,2H),2.64(m,5H),2.32(m,3H),1.74(d,J=7.1Hz,3H),1.04(m,9H),0.92(d,J=6.7Hz,3H). 13 C NMR(150MHz,CDCl3)δ172.44,171.27,170.85,168.89,168.06,164.22,132.46,129.23,70.89,63.94,60.45,58.56,52.93,39.24,35.29,32.35,29.28,28.93,21.09,19.52,19.33,18.74,17.76,14.19,13.52.ESI-MS(m / z):583.0[M+H] + 。

Claims

1. A method for preparing a compound represented by general formula (I), characterized in that: In the general formula (I), A is a bridge connecting two sulfur atoms, which is atom-free, i.e., the two sulfur atoms are directly connected; or is a carbonyl group or a thiocarbonyl group, i.e., the two sulfur atoms are connected through a carbonyl group or a thiocarbonyl group; The preparation method is carried out according to the following synthetic route: These include: first step Compound 3 is generated from 2-ketobutyric acid 1 and benzyl carbamate 2 in the presence of an acid, under a suitable solvent and temperature; the acid is selected from CH3SO3H, p-toluenesulfonic acid or camphorsulfonic acid; the solvent is dichloromethane, chloroform or toluene; the reaction temperature is 0-120°C; Step 2 Compound 3 generates compound 4 under suitable reagent and temperature; the reagent is selected from acetyl chloride, thionyl chloride or any combination thereof; the reaction temperature is 0-80°C; Step 3 Compound 4 and cysteine ​​5 containing a protective group are condensed by a base under the conditions of a suitable condensing agent, solvent and reaction temperature; then, under the action of a base, the compound is aminolyzed with valine methyl ester hydrochloride 6 to prepare compound 7 by a one-pot method; the condensing agent is selected from EDCI, DCC, HOAT, HOBT, HATU, PyBOP or DIC; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile, toluene, water or a combination thereof; the reaction temperature is 0-80°C; Step 4 Compound 7 is reacted with an acid in a suitable solvent and reaction temperature to undergo a deprotection reaction to prepare compound 8 containing a free amino group; the acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, trifluoroacetic acid, boron trifluoride etherate, or an acid generated in situ, such as acetyl chloride / methanol, acetyl chloride / ethanol, TMSCl / methanol, TMSCl / ethanol, TMSCl / isopropanol, TMSBr / methanol, TMSBr / ethanol, TMSI / methanol, TMSI / ethanol; the solvent is selected from water, methanol, ethanol, dichloromethane, THF, 1,4-dioxane, DMF, DMSO, acetonitrile or a combination thereof; the reaction temperature is 0-80°C; Step 5 Compound 8 and valine 9 containing a protecting group undergo a condensation reaction under the conditions of a suitable condensing agent, a base, a solvent and a reaction temperature to prepare compound 10; the condensing agent is selected from EDCI, DCC, HOAT, HOBT, HATU, DIC or PyBOP; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from an organic solvent such as tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile, toluene, etc.; the reaction temperature is 0-80°C; Step 6 Compound 10 is subjected to a deprotection reaction under the conditions of a suitable solvent and reaction temperature through the action of an acid to prepare a compound 11 containing a free amino group; the acid is selected from hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, trifluoroacetic acid, boron trifluoride etherate, or an acid generated in situ, such as acetyl chloride / methanol, acetyl chloride / ethanol, TMSCl / methanol, TMSCl / ethanol, TMSCl / isopropanol, TMSBr / methanol, TMSBr / ethanol, TMSI / methanol, TMSI / ethanol; the solvent is selected from water, methanol, ethanol, dichloromethane, THF, 1,4-dioxane, DMF, DMSO, acetonitrile or a combination thereof; the reaction temperature range is 0-80°C; Step 7 Compound 11 and chiral side chain 12 undergo an aminolysis reaction with a base under suitable solvent and reaction temperature conditions to generate compound 13; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile or toluene; the reaction temperature is 0-80°C; Step 8 Compound 13 is hydrolyzed by a base under suitable solvent and reaction temperature conditions to prepare compound 14; the base is selected from LiOH, NaOH, KOH, Bu3SnOH or Me3SnOH; the solvent is selected from water, tetrahydrofuran, methanol, ethanol, acetonitrile or a combination thereof; the reaction temperature is -10-80°C; Step 9 Compound 14 undergoes macrocyclic lactonization with configuration inversion in the presence of a suitable organic phosphine, an azo compound, an acid, a solvent and a temperature to obtain compound 15; wherein the organic phosphine is selected from Ph3P, (p-Tol)3P, Bu3P or Me3P; the azo compound is selected from DEAD or DIAD; the acid is selected from CH3SO3H, p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, N,N-dimethylformamide, acetonitrile or a combination thereof; and the temperature is 0-80°C. Compound 15 undergoes a deprotection reaction and the formation of an intramolecular disulfide bond under the action of an oxidant in a suitable solvent and reaction temperature to prepare compound 16; the solvent is dichloromethane, 1,2-dichloroethane, THF, 1,4-dioxane, methanol, ethanol or acetonitrile; the reaction temperature range is 0-80°C; the oxidant is selected from I2, Br2, H2O2, DDQ, O2, PhIO or pyridine N-oxide; Step 10 Compound 16 is subjected to the action of a reducing agent under the conditions of a base, a suitable solvent and a reaction temperature, and the disulfide bond of the compound 16 is broken to generate a dithiol compound; the reducing agent is selected from Ph3P, (p-Tol)3P, Bu3P or TCEP hydrochloride; the base is selected from potassium carbonate, sodium carbonate, sodium bicarbonate, DMAP, pyridine, Et3N, DIPEA, DBU or imidazole; the solvent is selected from toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, N,N-dimethylformamide, acetonitrile, methanol, ethanol, water or a combination thereof; the reaction temperature range is 0-80°C; The prepared dithiol compound is subjected to the action of a carbonylation agent or a thiocarbonylation agent under the conditions of a suitable solvent and a reaction temperature to generate a dithiocarbonate or a dithiocarbonate thioester compound; the carbonylation agent or the thiocarbonylation agent is selected from phosgene (ClCOCl), triphosgene [(COCl2)3], triethylamine, DIPEA, pyridine, DMAP, imidazole, diimidazole carbonyl compound (Im-CO-Im), diimidazole thiocarbonyl compound (Im-CS-Im) or a combination thereof; the solvent is selected from toluene, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, N,N-dimethylformamide, acetonitrile, methanol, ethanol, water or a combination thereof; and the reaction temperature range is 0-80°C.

2. The preparation method according to claim 1, characterized in that: The compound of general formula (I) is prepared according to the following synthesis route: Among them, the synthetic route is: Includes steps: first step Compound 3 is generated from 2-ketobutyric acid 1 and benzyl carbamate 2 in the presence of an acid, under a suitable solvent and temperature; the acid is selected from p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from toluene; and the reaction temperature is 20-120°C; Step 2 Compound 3 generates compound 4 under suitable reagent and temperature; the reagent is selected from acetyl chloride, thionyl chloride or any combination thereof; the reaction temperature is 0-80°C; Step 3 Compound 4 and cysteine ​​5 containing a protecting group are condensed under the action of a base under the conditions of a suitable condensing agent, solvent and reaction temperature; the compound 4 is then subjected to aminolysis with valine methyl ester hydrochloride 6 under the action of a base to prepare compound 7 in one pot; the condensing agent is selected from EDCI, DCC, HOAT, HOBT, HATU, PyBOC or DIC; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile, toluene, water or a combination thereof; the reaction temperature is 0-80°C; Step 4 Compound 7 undergoes a deprotection reaction under the action of an acid in a suitable solvent and reaction temperature to prepare compound 8 containing a free amino group; the acid is selected from trifluoroacetic acid and boron trifluoride ether; the solvent is selected from dichloromethane; the reaction temperature is 0-80°C; Step 5 Compound 8 and valine 9 containing a protecting group undergo a condensation reaction under the conditions of a suitable condensing agent, a base, a solvent and a reaction temperature to prepare compound 10; the condensing agent is selected from EDCI, DCC, HOAT, HOBT, HATU, DIC or PyBOP or a combination thereof; the base is selected from DMAP, pyridine, Et3N, DIPEA, DBU or a combination thereof; the solvent is selected from tetrahydrofuran, ether, dichloromethane, DMF, acetonitrile, or toluene; the reaction temperature is 0-80°C; Step 6 Compound 10 undergoes a deprotection reaction under the action of an acid in a suitable solvent and reaction temperature to prepare compound 11 containing a free amino group; the acid is selected from trifluoroacetic acid and boron trifluoride ether; the solvent is selected from dichloromethane; the reaction temperature range is, for example, 0-80°C; Step 7 Compound 11 and chiral side chain 12 undergo aminolysis reaction under the action of a base in a suitable solvent and reaction temperature to generate compound 13; the base is selected from DMAP; the solvent is selected from dichloromethane; the reaction temperature is 0-80°C; Step 8 Compound 13 undergoes hydrolysis reaction under the action of a base in a suitable solvent and reaction temperature to prepare compound 14; the base is selected from LiOH, Bu3SnOH or Me3SnOH; the solvent is selected from water, tetrahydrofuran or a combination thereof; the reaction temperature is -10-80°C; Step 9 Compound 14 undergoes macrocyclic lactonization with configuration inversion in the presence of a suitable organic phosphine, an azo compound, an acid, a solvent and a temperature to obtain compound 15; wherein the organic phosphine is selected from Ph3P, (p-Tol)3P, Bu3P or Me3P; the azo compound is selected from DEAD or DIAD; the acid is selected from p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from tetrahydrofuran, dichloromethane or a combination thereof; and the temperature is 0-80°C. Compound 15 undergoes a deprotection reaction and the formation of an intramolecular disulfide bond under the action of an oxidant in a suitable solvent and reaction temperature conditions to prepare compound 16; the solvent is selected from tetrahydrofuran, dichloromethane, methanol or a combination thereof; the reaction temperature range is 0-80°C; and the oxidant is selected from I2.

3. The preparation method according to claim 1, characterized in that: The compound of general formula (I) is prepared according to the following synthesis route: Among them, the synthetic route is: Includes steps: first step Compound 3 is generated from 2-ketobutyric acid 1 and benzyl carbamate 2 in the presence of an acid, under a suitable solvent and temperature; the acid is selected from p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from toluene; and the reaction temperature is 80-120°C; Step 2 Compound 3 generates compound 4 under suitable reagent and temperature; the reagent is selected from acetyl chloride, thionyl chloride or any combination thereof; the reaction temperature is 0-40°C; Step 3 Compound 4 and cysteine ​​5 containing a protective group are condensed under the action of a base under the conditions of a suitable condensing agent, solvent and reaction temperature; the compound 4 is then aminolyzed with valine methyl ester hydrochloride 6 under the action of a base to prepare compound 7 in one pot; the condensing agent is selected from DIC; the base is selected from DMAP, pyridine, Et3N or a combination thereof; the solvent is selected from tetrahydrofuran, dichloromethane or a combination thereof; the reaction temperature is 0-65°C; Step 4 Compound 7 undergoes a deprotection reaction under the action of an acid in a suitable solvent and reaction temperature to prepare compound 8 containing a free amino group; the acid is selected from trifluoroacetic acid and boron trifluoride ether; the solvent is selected from dichloromethane; the reaction temperature is 0-60°C; Step 5 Compound 8 and valine 9 containing a protecting group undergo a condensation reaction under the conditions of a suitable condensing agent, a base, a solvent and a reaction temperature to prepare compound 10; the condensing agent is selected from PyBOP; the base is selected from DMAP and DIPEA; the solvent is selected from dichloromethane; the reaction temperature is 0-40°C; Step 6 Compound 10 undergoes a deprotection reaction under the action of an acid in a suitable solvent and reaction temperature to prepare compound 11 containing a free amino group; the acid is selected from trifluoroacetic acid and boron trifluoride ether; the solvent is selected from dichloromethane; the reaction temperature range is, for example, 0-60°C; Step 7 Compound 11 and chiral side chain 12 undergo aminolysis reaction under the action of a base in a suitable solvent and reaction temperature to generate compound 13; the base is selected from DMAP; the solvent is selected from dichloromethane; the reaction temperature is 0-60°C; Step 8 Compound 13 undergoes hydrolysis reaction under the action of a base in a suitable solvent and reaction temperature to prepare compound 14; the base is selected from LiOH or Me3SnOH; the solvent is selected from water, tetrahydrofuran or a combination thereof; the reaction temperature is -10-40°C; Step 9 Compound 14 undergoes macrocyclic lactonization with configuration inversion in the presence of a suitable organic phosphine, an azo compound, an acid, a solvent and a temperature to obtain compound 15; wherein the organic phosphine is selected from Ph3P; the azo compound is selected from DEAD or DIAD; the acid is selected from p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from tetrahydrofuran, dichloromethane or a combination thereof; and the temperature is 0-80°C. Compound 15 undergoes a deprotection reaction and the formation of an intramolecular disulfide bond under the action of an oxidant in a suitable solvent and reaction temperature to prepare compound 16; the solvent is selected from tetrahydrofuran, dichloromethane, methanol or a combination thereof; the reaction temperature range is 0-40° C.; the oxidant is selected from I2; Step 10 Compound 16 is subjected to the action of a reducing agent under the conditions of a base, a suitable solvent and a reaction temperature, and the disulfide bond of the compound 16 is broken to generate a dithiol compound; the reducing agent is selected from Ph3P or TCEP hydrochloride; the base is selected from potassium carbonate and sodium carbonate; the solvent is selected from dichloromethane, water or a combination thereof; the reaction temperature range is 0-40°C; The prepared dithiol compound is subjected to the action of a carbonylation reagent under the conditions of a suitable solvent and a reaction temperature to generate a dithiocarbonate compound; the carbonylation reagent is selected from a diimidazole carbonyl compound (Im-CO-Im); the solvent is selected from dichloromethane; and the reaction temperature range is 0-40°C.

4. The preparation method according to claim 1, characterized in that: The compound of general formula (I) is prepared according to the following synthesis route: Among them, the synthetic route is: Includes steps: first step Compound 3 is generated from 2-ketobutyric acid 1 and benzyl carbamate 2 in the presence of an acid, under a suitable solvent and temperature; the acid is selected from p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from toluene; and the reaction temperature is 80-120°C; Step 2 Compound 3 generates compound 4 under suitable reagent and temperature; the reagent is selected from acetyl chloride, thionyl chloride or any combination thereof; the reaction temperature is 0-40°C; Step 3 Compound 4 and cysteine ​​5 containing a protective group are condensed under the action of a base under the conditions of a suitable condensing agent, solvent and reaction temperature; the compound 4 is then aminolyzed with valine methyl ester hydrochloride 6 under the action of a base to prepare compound 7 in one pot; the condensing agent is selected from DIC; the base is selected from DMAP, pyridine, Et3N or a combination thereof; the solvent is selected from tetrahydrofuran, dichloromethane or a combination thereof; the reaction temperature is 0-65°C; Step 4 Compound 7 undergoes a deprotection reaction under the action of an acid in a suitable solvent and reaction temperature to prepare compound 8 containing a free amino group; the acid is selected from boron trifluoride ether; the solvent is selected from dichloromethane; the reaction temperature is 0-40°C; Step 5 Compound 8 and valine 9 containing a protecting group undergo a condensation reaction under the conditions of a suitable condensing agent, a base, a solvent and a reaction temperature to prepare compound 10; the condensing agent is selected from PyBOP; the base is selected from DMAP and DIPEA; the solvent is selected from dichloromethane; the reaction temperature is 0-40°C; Step 6 Compound 10 undergoes a deprotection reaction under the action of an acid in a suitable solvent and reaction temperature to prepare compound 11 containing a free amino group; the acid is selected from boron trifluoride etherate; the solvent is selected from dichloromethane; the reaction temperature range is, for example, 0-60°C; Step 7 Compound 11 and chiral side chain 12 undergo aminolysis reaction under the action of a base in a suitable solvent and reaction temperature to generate compound 13; the base is selected from DMAP; the solvent is selected from dichloromethane; the reaction temperature is 0-60°C; Step 8 Compound 13 undergoes hydrolysis reaction under the action of a base in a suitable solvent and reaction temperature to prepare compound 14; the base is selected from LiOH; the solvent is selected from water, tetrahydrofuran or a combination thereof; the reaction temperature is -10-40°C; Step 9 Compound 14 undergoes macrocyclic lactonization with configuration inversion in the presence of a suitable organic phosphine, an azo compound, an acid, a solvent and a temperature to obtain compound 15; wherein the organic phosphine is selected from Ph3P; the azo compound is selected from DIAD; the acid is selected from p-toluenesulfonic acid or camphorsulfonic acid; the solvent is selected from tetrahydrofuran; and the temperature is 0-40°C. Compound 15 undergoes a deprotection reaction and the formation of an intramolecular disulfide bond under the action of an oxidant in a suitable solvent and reaction temperature to prepare compound 16; the solvent is selected from dichloromethane, methanol or a combination thereof; the reaction temperature range is 0-40°C; the oxidant is selected from I2; Step 10 Compound 16 is subjected to the action of a reducing agent under the conditions of a base, a suitable solvent and a reaction temperature, and the disulfide bond of the compound 16 is broken to generate a dithiol compound; the reducing agent is selected from TCEP hydrochloride; the base is selected from potassium carbonate; the solvent is selected from dichloromethane, water or a combination thereof; the reaction temperature range is 0-40°C; The prepared dithiol compound is subjected to the action of a thiocarbonylation reagent under the conditions of a suitable solvent and a reaction temperature to generate a thiocarbonate dithioester compound; the thiocarbonylation reagent is selected from a diimidazole thiocarbonyl compound (Im-CS-Im); the solvent is selected from dichloromethane; and the reaction temperature range is 0-40°C.

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