A solid-phase synthesis method for epitubatide

Abstract

This invention discloses a solid-phase synthesis method for eptifibatide, belonging to the field of pharmaceutical synthesis technology. The solid-phase synthesis steps include: sequentially coupling amino acids onto Rink Amide-AM resin using a solid-phase synthesis method; after treatment with a removal buffer; reacting with N,N'-di-BOC-1H-1-guanidinopyrazole under organic base conditions; subsequently forming disulfide bonds through iodine oxidation; and cleavage and purification with a lysis buffer to obtain eptifibatide. The organic base is N,N-diisopropylethylamine or N-methylmorpholine; the lysis buffer is a mixture of trifluoroacetic acid, triisopropylsilane, and water; and the removal buffer is a mixture of trifluoroacetic acid, triisopropylsilane, and dichloromethane. The solid-phase synthesis method for eptifibatide disclosed in this invention can effectively improve the resin cleavage efficiency of eptifibatide, increase the purity of crude eptifibatide, and improve the yield of the final eptifibatide.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical synthesis technology, specifically to a solid-phase synthesis method for eptifibatide. Background Technology

[0002] Eptifibatide is a synthetic cyclic peptide containing one mercaptopropionic acid and six amino acid residues. It is a specific antagonist of the platelet glycoprotein GPIIb / IIIa receptor, selectively and reversibly inhibiting the binding of plasma coagulation factor I to GPIIb / IIIa, inhibiting the final common pathway of platelet aggregation, and reversing ischemic states caused by thrombosis. Clinically, eptifibatide is mainly used to treat unstable angina and acute myocardial infarction.

[0003] Currently, there are two main methods for the synthesis of eptifibatide: solid-phase synthesis and liquid-phase synthesis. For example, Chinese invention patent CN103450346A reports a liquid-phase synthesis method for eptifibatide: The method involves sequentially synthesizing peptide fragments H-Asp(OtBu)-Trp-Pro-Cys(Trt)-NH2 and Mpa(Trt)-Lys(Boc)-Gly-OMe, coupling the two fragments to obtain a heptapeptide linear peptide, cyclizing it, removing the side-chain protecting groups, and then using thiourea trioxide to convert the amino group of the arginine-containing peptide to a guanidinium group, thus obtaining eptifibatide. This method is cumbersome and has a long synthesis cycle. Solid-phase synthesis is a commonly used method, but the high-arginine raw material used in current solid-phase synthesis methods is Fmoc-HomoArg(Pbf)-OH, which suffers from problems such as cumbersome synthesis, high cost, and difficulty in obtaining the raw material. To address the challenges of complex, costly, and difficult-to-obtain high-arginine synthesis in existing technologies, a novel solid-phase synthesis method for eptifibatide is needed. Summary of the Invention

[0004] The purpose of this invention is to provide a solid-phase synthesis method for eptifibatide, which not only improves the cutting efficiency of eptifibatide peptide resin, but also reduces impurities in crude eptifibatide, increases the purity of crude eptifibatide, helps to reduce the difficulty and cost of subsequent purification processes, reduces the loss of eptifibatide during purification, increases the yield of the final prepared eptifibatide, and realizes the industrial production of eptifibatide.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0006] A solid-phase synthesis method for epitubatide includes: sequentially coupling amino acids onto Rink Amide-AM resin using a solid-phase synthesis method; after treatment with a removal solution, reacting the amino acids with N,N'-di-BOC-1H-1-guanidinylpyrazole under organic base conditions; subsequently forming disulfide bonds through iodine oxidation; and obtaining epitubatide after cleavage treatment with a lysis buffer and purification; wherein the organic base is N,N-diisopropylethylamine or N-methylmorpholine; the molar ratio of the organic base to N,N'-di-BOC-1H-1-guanidinylpyrazole is 1:0.5-2; and the lysis buffer is a mixture of trifluoroacetic acid, triisopropylsilane, and water.

[0007] This invention couples Fmoc-Lys(Mtt)-OH into a peptide resin, then uses a solid-phase method to remove the Mtt protecting group from the side chain, exposing the amino group. Finally, it reacts with N,N'-di-BOC-1H-1-guanidinopyrazole to construct the important structural component of epitubapeptide, homoarginine (HomoArg). The Fmoc-Lys(Mtt)-OH and N,N'-di-BOC-1H-1-guanidinopyrazole used in this invention are inexpensive and readily available, have minimal environmental impact, and utilize a solid-phase oxidation method, avoiding liquid-phase oxidation operations, reducing wastewater generation, and significantly lowering the cost of solid-phase synthesis. This invention is simple to operate, low in cost, and suitable for industrial production, providing a promising prospect for the industrial production of epitubapeptide.

[0008] Preferably, the lysis buffer is a mixture of trifluoroacetic acid, triisopropylsilane, benzoxazole ester derivative and water.

[0009] More preferably, the preparation method of the benzoxazole ester derivative includes first reacting 6-hydroxy-1,3-benzoxazole thiol-2-one with 4-pentenoyl chloride in the presence of pyridine, and then reacting it with dimethylphenylsilane in the presence of a Karstedt catalyst to obtain the benzoxazole ester derivative. This invention introduces the benzoxazole ester derivative prepared by reacting 6-hydroxy-1,3-benzoxazole thiol-2-one, 4-pentenoyl chloride, and dimethylphenylsilane as raw materials into the lysis buffer. This may capture the active carbocation generated during the lysis process through nucleophilic interaction, effectively inhibiting side reactions of amino acid side chains. This not only improves the cleavage efficiency of peptide resin but also reduces impurities in the crude peptide product, increasing the purity of the crude peptide product. This helps reduce the difficulty and cost of subsequent purification processes, reduces peptide product loss during purification, and increases the yield of the final prepared peptide product.

[0010] More preferably, the mass ratio of pyridine to 6-hydroxy-1,3-benzothiol-2-one and pyridine is 1:1-5.

[0011] More preferably, the mass ratio of 6-hydroxy-1,3-benzothiol-2-one to 4-pentenoyl chloride is 1:0.5-2.

[0012] More preferably, the mass ratio of 6-hydroxy-1,3-benzothiol-2-one to dimethylphenylsilane is 1:0.2-1.

[0013] Preferably, the amino acid coupling sequence is Fmoc-Cys(Trt)-OH, Fmoc-Pro-OH, Fmoc-Trp(Boc)-OH, Fmoc-Asp(OtBu)-OH, Fmoc-Gly-OH, Fmoc-Lys(Mtt)-OH and Mpa(Trt)-OH.

[0014] Preferably, the removal solution is a mixture of trifluoroacetic acid, triisopropylsilane and dichloromethane.

[0015] More preferably, the volume ratio of trifluoroacetic acid to triisopropylsilane is 1:0.5-4.

[0016] More preferably, the volume ratio of trifluoroacetic acid to dichloromethane is 1:31-97.

[0017] Preferably, a solid-phase synthesis method for eptifibatide specifically comprises:

[0018] S1. Weigh Rink Amide-AM resin, add N,N-dimethylformamide (DMF) and stir for 0.5-1 h. Dry the reaction solution under vacuum, wash the resin with DMF, add deprotecting reagent and react for 25-30 min.

[0019] S2. Add Fmoc-Cys(Trt)-OH, N'N-diisopropylcarbodiimide (DIC) and ethyl 2-oxime cyanoacetate (Oxyma Pure), add DMF and stir for 2-3 hours. After the reaction is complete, dry the reaction solution and add a deprotecting agent for 25-30 minutes.

[0020] S3. Add Fmoc-Pro-OH, DIC and Oxyma Pure, add DMF and stir to react for 2-3 hours. After the reaction is complete, dry the reaction solution and add deprotecting reagent to react for 25-30 minutes.

[0021] S4. Add Fmoc-Trp(Boc)-OH, DIC and Oxyma Pure, add DMF and stir for 2-3 hours. After the reaction is complete, dry the reaction solution and add deprotecting reagent for 25-30 minutes.

[0022] S5. Add Fmoc-Asp(OtBu)-OH, DIC and Oxyma Pure, add DMF and stir to react for 2-3 hours. After the reaction is complete, dry the reaction solution and add deprotecting reagent to react for 25-30 minutes.

[0023] S6. Add Fmoc-Gly-OH, DIC and Oxyma Pure, add DMF and stir to react for 2-3 hours. After the reaction is complete, dry the reaction solution and add deprotecting reagent to react for 25-30 minutes.

[0024] S7. Add Fmoc-Lys(Mtt)-OH, DIC and Oxyma Pure, add DMF and stir for 2-3 hours. After the reaction is complete, dry the reaction solution and add deprotecting reagent for 25-30 minutes.

[0025] S8. Add Mpa(Trt)-OH, DIC and Oxyma Pure, add DMF and stir to react for 2-3 hours. After the reaction is complete, dry the reaction solution.

[0026] S9. Add the stripping solution and stir for 10-15 minutes. Drain the stripping solution. Add the stripping solution again and stir for 10-15 minutes. Drain the stripping solution. Add the stripping solution again and stir for 10-15 minutes. Drain the stripping solution. Wash the resin with DMF.

[0027] S10, add N,N'-di-BOC-1H-1-guanidinylpyrazole and organic base, add DMF and stir for 2-3 hours. After the reaction is complete, dry the reaction solution.

[0028] S11. Add iodine solution and stir for 10-20 min. Drain the reaction solution. Add iodine solution again and stir for 10-20 min. Drain the reaction solution. Add iodine solution again and stir for 10-20 min. Drain the reaction solution. Wash the resin with DMF to obtain epitubatide resin.

[0029] S12. Add lysis buffer and lyse for 2-6 hours to obtain crude epitubatide.

[0030] S13. The crude epitubatide was separated by high performance liquid chromatography (HPLC) to obtain epitubatide.

[0031] More preferably, the degree of substitution of Rink Amide-AM Resin in step S1 is 0.3-1.2 mmol / g.

[0032] More preferably, in step S1, the ratio of Rink Amide-AM Resin to DMF is 1g:5-20mL.

[0033] More preferably, the deprotecting agent in step S1 is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0034] More preferably, in step S1, the ratio of Rink Amide-AM Resin to deprotecting reagent is 1g:5-20mL.

[0035] More preferably, in step S2, the molar ratio of Fmoc-Cys(Trt)-OH to DIC is 1:0.5-2.

[0036] More preferably, the molar ratio of Fmoc-Cys(Trt)-OH to Oxyma Pure in step S2 is 1:0.5-2.

[0037] More preferably, in step S2, the ratio of Fmoc-Cys(Trt)-OH to DMF is 1 mmol: 1-5 mL.

[0038] More preferably, the deprotecting agent in step S2 is a mixture of piperidine (Pip) and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0039] More preferably, in step S2, the ratio of Fmoc-Cys(Trt)-OH to the deprotecting reagent is 1 mmol: 1-5 mL.

[0040] More preferably, the molar ratio of Fmoc-Pro-OH to DIC in step S3 is 1:0.5-2.

[0041] More preferably, the molar ratio of Fmoc-Pro-OH to Oxyma Pure in step S3 is 1:0.5-2.

[0042] More preferably, in step S3, the ratio of Fmoc-Pro-OH to DMF is 1 mmol: 1-5 mL.

[0043] More preferably, the deprotecting agent in step S3 is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0044] More preferably, in step S3, the ratio of Fmoc-Pro-OH to the deprotecting reagent is 1 mmol: 1-5 mL.

[0045] More preferably, in step S4, the molar ratio of Fmoc-Trp(Boc)-OH to DIC is 1:0.5-2.

[0046] More preferably, in step S4, the molar ratio of Fmoc-Trp(Boc)-OH to Oxyma Pure is 1:0.5-2.

[0047] More preferably, in step S4, the ratio of Fmoc-Trp(Boc)-OH to DMF is 1 mmol: 1-5 mL.

[0048] More preferably, the deprotecting agent in step S4 is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0049] More preferably, in step S4, the ratio of Fmoc-Trp(Boc)-OH to the deprotecting reagent is 1 mmol: 1-5 mL.

[0050] More preferably, in step S5, the molar ratio of Fmoc-Asp(OtBu)-OH to DIC is 1:0.5-2.

[0051] More preferably, in step S5, the molar ratio of Fmoc-Asp(OtBu)-OH to Oxyma Pure is 1:0.5-2.

[0052] More preferably, in step S5, the ratio of Fmoc-Asp(OtBu)-OH to DMF is 1 mmol: 1-5 mL.

[0053] More preferably, the deprotecting agent in step S5 is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0054] More preferably, in step S5, the ratio of Fmoc-Asp(OtBu)-OH to the deprotecting reagent is 1 mmol: 1-5 mL.

[0055] More preferably, the molar ratio of Fmoc-Gly-OH to DIC in step S6 is 1:0.5-2.

[0056] More preferably, the molar ratio of Fmoc-Gly-OH to Oxyma Pure in step S6 is 1:0.5-2.

[0057] More preferably, in step S6, the ratio of Fmoc-Gly-OH to DMF is 1 mmol: 1-5 mL.

[0058] More preferably, the deprotecting agent in step S6 is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0059] More preferably, in step S6, the ratio of Fmoc-Gly-OH to the deprotecting reagent is 1 mmol: 1-5 mL.

[0060] More preferably, in step S7, the molar ratio of Fmoc-Lys(Mtt)-OH to DIC is 1:0.5-2.

[0061] More preferably, in step S7, the molar ratio of Fmoc-Lys(Mtt)-OH to Oxyma Pure is 1:0.5-2.

[0062] More preferably, in step S7, the ratio of Fmoc-Lys(Mtt)-OH to DMF is 1 mmol: 1-5 mL.

[0063] More preferably, the deprotecting agent in step S7 is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:2-8.

[0064] More preferably, in step S7, the ratio of Fmoc-Lys(Mtt)-OH to the deprotecting reagent is 1 mmol: 1-5 mL.

[0065] More preferably, in step S8, the molar ratio of MPa(Trt)-OH to DIC is 1:0.5-2.

[0066] More preferably, in step S8, the molar ratio of Mpa(Trt)-OH to Oxyma Pure is 1:0.5-2.

[0067] More preferably, in step S8, the ratio of Mpa(Trt)-OH to DMF is 1 mmol: 1-5 mL.

[0068] More preferably, the removal solution in step S9 is a mixture of trifluoroacetic acid (TFA), triisopropylsilane (Tis), and dichloromethane (DCM).

[0069] More preferably, the volume ratio of trifluoroacetic acid to triisopropylsilane is 1:0.5-4.

[0070] More preferably, the volume ratio of trifluoroacetic acid to dichloromethane is 1:31-97.

[0071] More preferably, the organic base in step S10 is N,N-diisopropylethylamine or N-methylmorpholine.

[0072] More preferably, in step S10, the molar ratio of the organic base and N,N'-bis-BOC-1H-1-guanidinylpyrazole is 1:0.5-2.

[0073] More preferably, in step S10, the ratio of N,N'-di-BOC-1H-1-guanidinylpyrazole to DMF is 1 mmol: 2-10 mL.

[0074] More preferably, the iodine solution in step S11 is a mixture of iodine and DMF.

[0075] More preferably, the ratio of elemental iodine to DMF is 1g:1-5mL.

[0076] More preferably, the lysis buffer in step S12 is a mixture of TFA, Tis, water, and at least one of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole. The present invention further introduces 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer. This may be due to the steric hindrance effect generated by 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole, which blocks the interaction between the active intermediate and the amino acid side chain in the lysis buffer, thus helping to further improve the cleavage efficiency, reduce impurities in the crude peptide product, improve the purity of the crude peptide product, and thereby increase the yield of the final prepared peptide product.

[0077] More preferably, the volume ratio of Tis to TFA is 1:20-50.

[0078] More preferably, the volume ratio of Tis to water is 1:0.5-2.

[0079] More preferably, the volume ratio of Tis to benzoxazole ester derivative is 1:0.05-0.1.

[0080] More preferably, the ratio of water to 3-(2-pyridinedithio)propionic acid is 1 mL: 0.03-0.07 g.

[0081] More preferably, the ratio of water to 3-amino-5-hydroxypyrazole is 1 mL: 0.02-0.05 g.

[0082] More preferably, the preparation method of the benzoxazole ester derivative is as follows:

[0083] 6-Hydroxy-1,3-benzoxazol-2-one was dissolved in tetrahydrofuran, and pyridine was added and stirred until homogeneous. 4-Pentenoyl chloride was slowly added under ice bath conditions, and the reaction was stirred at room temperature for 2-8 h. After the reaction was completed, Karstedt catalyst was added under nitrogen atmosphere and stirred for 0.5-2 h. Dimethylphenylsilane was slowly added, and the reaction was carried out at 70-90 °C for 8-24 h. After the reaction was completed, deionized water was added and stirred, and then the mixture was naturally cooled to room temperature. The mixture was extracted with ethyl acetate, and the organic phase was retained and washed 1-5 times with saturated sodium chloride solution to obtain benzoxazole derivatives.

[0084] More preferably, the ratio of 6-hydroxy-1,3-benzothiol-2-one to tetrahydrofuran is 1 g: 10-50 mL.

[0085] More preferably, the mass ratio of pyridine to 6-hydroxy-1,3-benzothiol-2-one and pyridine is 1:1-5.

[0086] More preferably, the mass ratio of 6-hydroxy-1,3-benzothiol-2-one to 4-pentenoyl chloride is 1:0.5-2.

[0087] More preferably, the volume ratio of tetrahydrofuran to Karstedt catalyst is 1:0.002-0.01.

[0088] More preferably, the mass ratio of 6-hydroxy-1,3-benzothiol-2-one to dimethylphenylsilane is 1:0.2-1.

[0089] More preferably, the volume ratio of tetrahydrofuran to deionized water is 1:0.1-0.5.

[0090] More preferably, the volume ratio of tetrahydrofuran to ethyl acetate is 1:0.5-2.

[0091] More preferably, the volume ratio of tetrahydrofuran to saturated sodium chloride solution is 1:0.5-2.

[0092] This invention introduces a benzoxazole ester derivative, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole into the lysis buffer. This benzoxazole ester derivative is obtained by reacting 6-hydroxy-1,3-benzoxazolethiol-2-one with 4-pentenoyl chloride and then further modifying with dimethylphenylsilane. Therefore, this invention has the following beneficial effects: Using the benzoxazole ester derivative prepared in this invention in synergistic application with 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole in the peptide resin lysis process of solid-phase synthesis of eptifibatide not only significantly improves the cleavage efficiency of the peptide resin and reduces the amount of residual resin, resulting in a high-purity crude eptifibatide and reducing the difficulty and cost of subsequent purification, but also helps to improve the yield of the final eptifibatide. Attached Figure Description

[0093] Figure 1 The image shows the infrared spectrum of a benzoxazole derivative.

[0094] Figure 2 This refers to the peptide resin cleavage efficiency.

[0095] Figure 3 The purity of crude eptifibatide.

[0096] Figure 4 The yield of eptifibatide. Detailed Implementation

[0097] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0098] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0099] The English-Chinese translation of the reagents used in this invention and their sources are shown in Tables 1 and 2. Table 1 shows the English-Chinese translation of the reagents used in this invention, and Table 2 shows the sources of the reagents used in this invention.

[0100] Table 1. English-Chinese bilingual text used in this invention

[0101]

[0102] Table 2 Sources of reagents used in this invention

[0103]

[0104] Example 1:

[0105] Solid-phase synthesis methods for epitubatide include,

[0106] S1. Weigh Rink Amide-AM Resin, add DMF and stir for 0.5 h, dry the reaction solution under vacuum, wash the resin with DMF, add deprotecting reagent and react for 25 min. The degree of substitution of Rink Amide-AM Resin is 0.95 mmol / g, and the volume ratio of Rink Amide-AM Resin to DMF is 1 g: 10 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Rink Amide-AM Resin to deprotecting reagent is 1 g: 10 mL.

[0107] S2. Add Fmoc-Cys(Trt)-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution and add a deprotecting reagent, then react for 25 minutes. The molar ratio of Fmoc-Cys(Trt)-OH to DIC is 1:1; the molar ratio of Fmoc-Cys(Trt)-OH to Oxyma Pure is 1:1; the volume ratio of Fmoc-Cys(Trt)-OH to DMF is 1 mmol: 3 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Fmoc-Cys(Trt)-OH to the deprotecting reagent is 1 mmol: 3.3 mL.

[0108] S3. Add Fmoc-Pro-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution and add a deprotecting reagent, then react for 25 minutes. The molar ratio of Fmoc-Pro-OH to DIC is 1:1; the molar ratio of Fmoc-Pro-OH to Oxyma Pure is 1:1; the volume ratio of Fmoc-Pro-OH to DMF is 1 mmol: 3 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Fmoc-Pro-OH to the deprotecting reagent is 1 mmol: 3.3 mL.

[0109] S4. Add Fmoc-Trp(Boc)-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution and add a deprotecting reagent, then react for 25 minutes. The molar ratio of Fmoc-Trp(Boc)-OH to DIC is 1:1; the molar ratio of Fmoc-Trp(Boc)-OH to Oxyma Pure is 1:1; the volume ratio of Fmoc-Trp(Boc)-OH to DMF is 1 mmol: 3 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Fmoc-Trp(Boc)-OH to the deprotecting reagent is 1 mmol: 3.3 mL.

[0110] S5. Add Fmoc-Asp(OtBu)-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution and add a deprotecting reagent, then react for 25 minutes. The molar ratio of Fmoc-Asp(OtBu)-OH to DIC is 1:1; the molar ratio of Fmoc-Asp(OtBu)-OH to Oxyma Pure is 1:1; the volume ratio of Fmoc-Asp(OtBu)-OH to DMF is 1 mmol: 3 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Fmoc-Asp(OtBu)-OH to the deprotecting reagent is 1 mmol: 3.3 mL.

[0111] S6. Add Fmoc-Gly-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution and add a deprotecting reagent, then react for 25 minutes. The molar ratio of Fmoc-Gly-OH to DIC is 1:1; the molar ratio of Fmoc-Gly-OH to Oxyma Pure is 1:1; the volume ratio of Fmoc-Gly-OH to DMF is 1 mmol: 3 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Fmoc-Gly-OH to the deprotecting reagent is 1 mmol: 3.3 mL.

[0112] S7. Add Fmoc-Lys(Mtt)-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution and add a deprotecting reagent, then react for 25 minutes. The molar ratio of Fmoc-Lys(Mtt)-OH to DIC is 1:1; the molar ratio of Fmoc-Lys(Mtt)-OH to Oxyma Pure is 1:1; the volume ratio of Fmoc-Lys(Mtt)-OH to DMF is 1 mmol: 3 mL; the deprotecting reagent is a mixture of Pip and DMF, with a volume ratio of Pip to DMF of 1:4; the volume ratio of Fmoc-Lys(Mtt)-OH to the deprotecting reagent is 1 mmol: 3.3 mL.

[0113] S8. Add Mpa(Trt)-OH, DIC, and Oxyma Pure, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution. The molar ratio of Mpa(Trt)-OH to DIC is 1:1; the molar ratio of Mpa(Trt)-OH to Oxyma Pure is 1:1; the volume ratio of Mpa(Trt)-OH to DMF is 1 mmol: 3 mL.

[0114] S9. Add the stripping solution and stir for 10 minutes. Drain the stripping solution. Add the stripping solution again and stir for 10 minutes. Drain the stripping solution again. Add the stripping solution again and stir for 10 minutes. Drain the stripping solution. Wash the resin thoroughly with DMF. The stripping solution is a mixture of TFA, Tis, and DCM, with a volume ratio of TFA to Tis of 1:2 and a volume ratio of TFA to DCM of 1:97.

[0115] S10. Add N,N'-di-BOC-1H-1-guanidinylpyrazole and DIEA, then add DMF and stir for 2 hours. After the reaction is complete, dry the reaction solution. The molar ratio of N,N'-di-BOC-1H-1-guanidinylpyrazole to DIEA is 1:1; the volume ratio of N,N'-di-BOC-1H-1-guanidinylpyrazole to DMF is 1 mmol: 5 mL.

[0116] S11. Add iodine solution and stir for 10 min. Drain the reaction solution. Add iodine solution again and stir for 10 min. Drain the reaction solution. Add iodine solution again and stir for 10 min. Drain the reaction solution. Wash the resin with DMF to obtain epitubatide resin. The iodine solution is a mixture of iodine and DMF, with a ratio of iodine to DMF of 1 g: 2 mL.

[0117] S12. Add lysis buffer and lyse for 3 hours to obtain crude epitubatide. The lysis buffer is a mixture of TFA, Tis and water, wherein the volume ratio of Tis to TFA is 1:36 and the volume ratio of Tis to water is 1:1.

[0118] S13. The crude epitubatide was separated by high performance liquid chromatography (HPLC) to obtain epitubatide.

[0119] Example 2:

[0120] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S9, the components of the desorption solution are replaced with a mixture of TFA, Tis and DCM, with a volume ratio of TFA to Tis of 1:1.3 and a volume ratio of TFA to DCM of 1:31, and other conditions are the same as in Example 1.

[0121] Example 3:

[0122] The solid-phase synthesis method of eptifibatide is the same as that in Example 1, except that DIEA is replaced with NMM in step S10.

[0123] Example 4:

[0124] Methods for preparing benzoxazole ester derivatives include,

[0125] 6-Hydroxy-1,3-benzoxazol-2-one was dissolved in tetrahydrofuran, pyridine was added and stirred until homogeneous, and 4-pentenoyl chloride was slowly added under ice bath conditions. The reaction was stirred at room temperature for 4 h. After the reaction was completed, Karstedt catalyst was added under nitrogen atmosphere and stirred for 1 h. Dimethylphenylsilane was slowly added and the reaction was carried out at 80 °C for 12 h. After the reaction was completed, deionized water was added and stirred. The mixture was then naturally cooled to room temperature and extracted with ethyl acetate. The organic phase was retained and washed three times with saturated sodium chloride solution to obtain the benzoxazol derivative. The mass ratio of 6-hydroxy-1,3-benzothiol-2-one to tetrahydrofuran was 1 g: 25 mL; the mass ratio of pyridine to 6-hydroxy-1,3-benzothiol-2-one was 1:3; the mass ratio of 6-hydroxy-1,3-benzothiol-2-one to 4-pentenoyl chloride was 1:1; the volume ratio of tetrahydrofuran to Karstedt catalyst was 1:0.005; the mass ratio of 6-hydroxy-1,3-benzothiol-2-one to dimethylphenylsilane was 1:0.4; the volume ratio of tetrahydrofuran to deionized water was 1:0.2; the volume ratio of tetrahydrofuran to ethyl acetate was 1:1; and the volume ratio of tetrahydrofuran to saturated sodium chloride solution was 1:1.

[0126] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, benzoxazole ester derivative and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to benzoxazole ester derivative is 1:0.1, and the volume ratio of Tis to water is 1:1, and other conditions are the same as in Example 1.

[0127] Example 5:

[0128] The preparation method of the benzoxazole ester derivative is the same as in Example 4.

[0129] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, benzoxazole ester derivative and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to benzoxazole ester derivative is 1:0.05, and the volume ratio of Tis to water is 1:1, and other conditions are the same as in Example 1.

[0130] Example 6:

[0131] The preparation method of the benzoxazole ester derivative is the same as in Example 4.

[0132] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, benzoxazole ester derivative, 3-(2-pyridinedithio)propionic acid, 3-amino-5-hydroxypyrazole and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to benzoxazole ester derivative is 1:0.1, the volume ratio of Tis to water is 1:1, the volume ratio of water to 3-(2-pyridinedithio)propionic acid is 1 mL:0.07 g, and the volume ratio of water to 3-amino-5-hydroxypyrazole is 1 mL:0.05 g, and other conditions are the same as in Example 1.

[0133] Example 7:

[0134] The preparation method of the benzoxazole ester derivative is the same as in Example 4.

[0135] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, benzoxazole ester derivative, 3-(2-pyridinedithio)propionic acid, 3-amino-5-hydroxypyrazole and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to benzoxazole ester derivative is 1:0.1, the volume ratio of Tis to water is 1:1, the mass ratio of water to 3-(2-pyridinedithio)propionic acid is 1 mL:0.03 g, and the mass ratio of water to 3-amino-5-hydroxypyrazole is 1 mL:0.05 g, and other conditions are the same as in Example 1.

[0136] Example 8:

[0137] The preparation method of the benzoxazole ester derivative is the same as in Example 4.

[0138] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, benzoxazole ester derivative, 3-(2-pyridinedithio)propionic acid, 3-amino-5-hydroxypyrazole and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to benzoxazole ester derivative is 1:0.1, the volume ratio of Tis to water is 1:1, the mass ratio of water to 3-(2-pyridinedithio)propionic acid is 1 mL:0.07 g, and the mass ratio of water to 3-amino-5-hydroxypyrazole is 1 mL:0.02 g, and other conditions are the same as in Example 1.

[0139] Comparative Example 1:

[0140] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, anisole, and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to anisole is 1:0.02, and the volume ratio of Tis to water is 1:1, and other conditions are the same as in Example 1.

[0141] Comparative Example 2:

[0142] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, 6-hydroxy-1,3-benzothiol-2-one and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to 6-hydroxy-1,3-benzothiol-2-one is 1:0.1, and the volume ratio of Tis to water is 1:1, and other conditions are the same as in Example 1.

[0143] Comparative Example 3:

[0144] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, 4-pentenoyl chloride and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to 4-pentenoyl chloride is 1:0.1, and the volume ratio of Tis to water is 1:1, and other conditions are the same as in Example 1.

[0145] Comparative Example 4:

[0146] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, dimethylphenylsilane and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to dimethylphenylsilane is 1:0.02, and the volume ratio of Tis to water is 1:1, and other conditions are the same as in Example 1.

[0147] Comparative Example 5:

[0148] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, 3-(2-pyridinedithio)propionic acid, 3-amino-5-hydroxypyrazole and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to water is 1:1, the volume ratio of water to 3-(2-pyridinedithio)propionic acid is 1 mL:0.07 g, and the volume ratio of water to 3-amino-5-hydroxypyrazole is 1 mL:0.05 g, and other conditions are the same as in Example 1.

[0149] Comparative Example 6:

[0150] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, 3-(2-pyridinedithio)propionic acid and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to water is 1:1, and the volume ratio of water to 3-(2-pyridinedithio)propionic acid is 1 mL:0.07 g, and other conditions are the same as in Example 1.

[0151] Comparative Example 7:

[0152] The solid-phase synthesis method of epitubatide, compared with Example 1, except that in step S12, the components of the lysis buffer are replaced with a mixture of TFA, Tis, 3-amino-5-hydroxypyrazole and water, wherein the volume ratio of Tis to TFA is 1:36, the volume ratio of Tis to water is 1:1, and the amount ratio of water to 3-amino-5-hydroxypyrazole is 1 mL:0.05 g, and other conditions are the same as in Example 1.

[0153] Experimental example:

[0154] 1. Material Characterization

[0155] The benzoxazole ester derivative prepared in Example 4 was characterized using Fourier transform infrared spectroscopy.

[0156] Figure 1 The image shows the infrared spectrum of a benzoxazole ester derivative. The results are as follows: Figure 1 As shown, 2900cm -1 An absorption peak for CH appears nearby, at 1750 cm⁻¹. -1 An absorption peak for C=O appears nearby, at 1650 cm⁻¹. -1 An absorption peak of C=C appears nearby, at 1230 cm⁻¹. -1 An absorption peak for COC appears nearby, at 1200 cm⁻¹. -1 An absorption peak for Si-C appears nearby, at 740 cm⁻¹. -1 An absorption peak for CS appears nearby. At 2100 cm⁻¹ -1 The absence of Si-H absorption peaks nearby indicates that the hydrosilylation reaction between the product of the reaction of 6-hydroxy-1,3-benzothiol-2-one and 4-pentenoyl chloride and dimethylphenylsilane was complete, successfully introducing dimethylphenylsilane into the chemical structure of the target product.

[0157] 2. Peptide resin cutting efficiency

[0158] The epituitaride resin was vacuum dried to constant weight. The mass of the epituitaride resin before cleavage was weighed and recorded as M1. The epituitaride resin was then cleaved for 3 hours with lysis buffer, washed with DMF, vacuum dried to constant weight, and the mass of the residual resin after cleavage was weighed and recorded as M2. The cleavage efficiency of the peptide resin was calculated as follows: Cleavage efficiency (%) = ((M1-M2) / (M1×degree of substitution of Rink Amide-AM Resin))×100%, where the degree of substitution of Rink Amide-AM Resin was 0.95 mmol / g.

[0159] The peptide resin cleavage efficiency of Examples 1, 4-8 and Comparative Examples 1-7 was determined according to the above methods.

[0160] Figure 2 The peptide resin cleavage efficiency is shown in the results. Figure 2 As shown, the cleavage yield of Examples 4-5 is higher than that of Examples 1 and Comparative Example 1. This is because, in the solid-phase synthesis of epitubatide, Examples 4-5 introduce a benzoxazole ester derivative prepared by reacting 6-hydroxy-1,3-benzoxazole thiol-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer, while Example 1 does not use a benzoxazole ester derivative, and Comparative Example 1 introduces anisole into the lysis buffer. This indicates that the introduction of a benzoxazole ester derivative into the lysis buffer in this invention helps to improve the peptide resin cleavage efficiency.

[0161] The higher cleavage efficiency of Examples 4-5 compared to Comparative Examples 2-4 is attributed to the fact that in the solid-phase synthesis of epitubatide, Examples 4-5 introduced a benzoxazole ester derivative prepared from 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer, while Comparative Examples 2-4 did not use a benzoxazole ester derivative. Specifically, Comparative Example 2 introduced 6-hydroxy-1,3-benzoxazole-2-one, Comparative Example 3 introduced 4-pentenoyl chloride, and Comparative Example 4 introduced dimethylphenylsilane into the lysis buffer. This indicates that using a benzoxazole ester derivative prepared from 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer effectively improves the peptide resin cleavage efficiency compared to using 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane.

[0162] The higher cleavage efficiency of Examples 6-8 compared to Examples 4-5 is due to the further introduction of 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer during the solid-phase synthesis of epitubatide in Examples 6-8. The higher cleavage efficiency of Examples 6-8 compared to Comparative Examples 5-7 is because, in the solid-phase synthesis of epitubatide, Comparative Example 5 only introduced 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer, without using benzoxazole ester derivatives; Comparative Example 6 only introduced 3-(2-pyridinedithio)propionic acid, and Comparative Example 7 only introduced 3-amino-5-hydroxypyrazole. This indicates that the synergistic use of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole in the lysis buffer in this invention helps to further improve the peptide resin cleavage efficiency.

[0163] Based on the data from Examples 4-8, it can be seen that the appropriate use of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole in the lysis buffer helps to improve the peptide resin cleavage efficiency.

[0164] 3. Purity of crude epitubapeptide

[0165] The crude epitubatide products prepared in Examples 1, 4-8 and Comparative Examples 1-7 were collected, and the purity of the crude epitubatide products was analyzed by reverse high performance liquid chromatography.

[0166] Figure 3 The purity of crude eptifibatide is shown in the results. Figure 3 As shown, the purity of crude epitubatide in Examples 4-5 is higher than that in Examples 1 and Comparative Example 1. This is because, in the solid-phase synthesis of epitubatide, Examples 4-5 introduce a benzoxazole ester derivative prepared from 6-hydroxy-1,3-benzoxazole thiol-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer, while Example 1 does not use a benzoxazole ester derivative, and Comparative Example 1 introduces anisole into the lysis buffer. This indicates that the introduction of a benzoxazole ester derivative into the lysis buffer in this invention helps to improve the purity of crude epitubatide.

[0167] The purity of crude epitaphthyl peptide in Examples 4-5 was higher than that in Comparative Examples 2-4. This is because, in the solid-phase synthesis of epitaphthyl peptide, Examples 4-5 introduced benzoxazole ester derivatives prepared by reacting 6-hydroxy-1,3-benzoxazole thiol-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer, while Comparative Examples 2-4 did not use benzoxazole ester derivatives. Specifically, Comparative Example 2 introduced 6-hydroxy-1,3-benzoxazole thiol-2-one into the lysis buffer, Comparative Example 3 introduced 4-pentenoyl chloride into the lysis buffer, and Comparative Example 4 introduced dimethylphenylsilane into the lysis buffer. This indicates that, compared to using benzoxazole ester derivatives prepared from 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane in the lysis buffer, the purity of crude epitubatide can be effectively improved.

[0168] The higher purity of crude epitubatide in Examples 6-8 compared to Examples 4-5 is due to the further introduction of 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer during the solid-phase synthesis of epitubatide in Examples 6-8. The higher purity of crude epitubatide in Examples 6-8 compared to Comparative Examples 5-7 is due to the fact that in the solid-phase synthesis of epitubatide, Comparative Example 5 only introduced 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer, without using benzoxazole ester derivatives; Comparative Example 6 only introduced 3-(2-pyridinedithio)propionic acid; and Comparative Example 7 only introduced 3-amino-5-hydroxypyrazole. This indicates that the synergistic use of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole in the lysis buffer in this invention helps to further improve the purity of crude epitubatide.

[0169] Based on the data from Examples 4-8, it can be seen that the appropriate use of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole in the lysis buffer helps to improve the purity of crude epitaphthylbutyrate.

[0170] 4. Yield of eptifibatide

[0171] The eptifibatide prepared in Examples 1-8 and Comparative Examples 1-7 were collected and weighed to obtain the actual yield of eptifibatide. The formula for calculating the yield of eptifibatide is: Yield (%) = Actual yield / Theoretical yield × 100%.

[0172] Figure 4 The yield of eptifibatide. Results are as follows: Figure 4As shown, the yield of epitubatide in Examples 4-5 was higher than that in Examples 1 and Comparative Example 1. This is because, in the solid-phase synthesis of epitubatide, Examples 4-5 introduced a benzoxazole ester derivative prepared from 6-hydroxy-1,3-benzoxazole thiol-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer, while Example 1 did not use a benzoxazole ester derivative, and Comparative Example 1 introduced anisole into the lysis buffer. This indicates that the introduction of a benzoxazole ester derivative into the lysis buffer in this invention helps to improve the yield of epitubatide.

[0173] The higher yields of epitubatide in Examples 4-5 compared to Comparative Examples 2-4 are attributed to the fact that in the solid-phase synthesis of epitubatide, Examples 4-5 introduced a benzoxazole ester derivative prepared from 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer, while Comparative Examples 2-4 did not use a benzoxazole ester derivative. Specifically, Comparative Example 2 introduced 6-hydroxy-1,3-benzoxazole-2-one into the lysis buffer, Comparative Example 3 introduced 4-pentenoyl chloride, and Comparative Example 4 introduced dimethylphenylsilane. This indicates that using a benzoxazole ester derivative prepared from 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane into the lysis buffer effectively improves the epitubatide yield compared to using 6-hydroxy-1,3-benzoxazole-2-one, 4-pentenoyl chloride, and dimethylphenylsilane.

[0174] The higher epitubeptide yields in Examples 6-8 compared to Examples 4-5 are due to the further introduction of 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer during the solid-phase synthesis of epitubeptide in Examples 6-8. The higher epitubeptide yields in Examples 6-8 compared to Comparative Examples 5-7 are because, in the solid-phase synthesis of epitubeptide, Comparative Example 5 only introduced 3-(2-pyridinedithio)propionic acid and 3-amino-5-hydroxypyrazole into the lysis buffer, without using benzoxazole ester derivatives; Comparative Example 6 only introduced 3-(2-pyridinedithio)propionic acid, and Comparative Example 7 only introduced 3-amino-5-hydroxypyrazole. This indicates that the synergistic use of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole in the lysis buffer in this invention helps to further improve the epitubeptide yield.

[0175] Based on the data from Examples 4-8, it can be seen that the appropriate use of benzoxazole ester derivatives, 3-(2-pyridinedithio)propionic acid, and 3-amino-5-hydroxypyrazole in the lysis buffer helps to improve the yield of epitaphthide.

[0176] The conventional operations in the operation steps of this invention are well known to those skilled in the art and will not be described in detail here.

[0177] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any changes and modifications made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solid-phase synthesis method for eptifibatide, comprising, An organic-base synthesis method was employed, in which amino acids were sequentially coupled onto Rink Amide-AM resin. After treatment with a descaling solution, the amino acids were reacted with N,N'-di-BOC-1H-1-guanidinopyrazole under organic-base conditions. Subsequently, disulfide bonds were formed by iodine oxidation, followed by cleavage and purification with a lysis buffer to obtain epitubatide. The organic base was N,N-diisopropylethylamine or N-methylmorpholine. The molar ratio of the organic base to N,N'-di-BOC-1H-1-guanidinopyrazole was 1:0.5-2. The lysis buffer was a mixture of trifluoroacetic acid, triisopropylsilane, benzoxazole ester derivative, and water. The preparation method of the benzoxazole ester derivative included reacting 6-hydroxy-1,3-benzoxazolethiol-2-one with 4-pentenoyl chloride under pyridine, followed by reaction with dimethylphenylsilane under Karstedt catalyst to obtain the benzoxazole ester derivative.

2. The solid-phase synthesis method of eptifibatide according to claim 1, characterized in that, The mass ratio of pyridine to 6-hydroxy-1,3-benzothiol-2-one and pyridine is 1:1-5.

3. The solid-phase synthesis method of eptifibatide according to claim 1, characterized in that, The mass ratio of 6-hydroxy-1,3-benzothiol-2-one to 4-pentenoyl chloride is 1:0.5-2.

4. The solid-phase synthesis method of eptifibatide according to claim 1, characterized in that, The mass ratio of 6-hydroxy-1,3-benzothiol-2-one to dimethylphenylsilane is 1:0.2-1.

5. The solid-phase synthesis method of eptifibatide according to claim 1, characterized in that, The amino acid coupling sequence is Fmoc-Cys(Trt)-OH, Fmoc-Pro-OH, Fmoc-Trp(Boc)-OH, Fmoc-Asp(OtBu)-OH, Fmoc-Gly-OH, Fmoc-Lys(Mtt)-OH and Mpa(Trt)-OH, respectively.

6. The solid-phase synthesis method of eptifibatide according to claim 1, characterized in that, The removal solution is a mixture of trifluoroacetic acid, triisopropylsilane, and dichloromethane.

7. The solid-phase synthesis method of eptifibatide according to claim 6, characterized in that, The volume ratio of trifluoroacetic acid to triisopropylsilane is 1:0.5-4.

8. The solid-phase synthesis method of eptifibatide according to claim 6, characterized in that, The volume ratio of trifluoroacetic acid to dichloromethane is 1:31-97.

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