Synthesis method of tilpotide

Abstract

The invention provides a method for synthesizing tirpotide by adopting a solid-liquid combination strategy. The preparation method comprises the following steps: firstly, respectively synthesizing full-protection peptide fragments (1-17) and (18-39), and then carrying out liquid-phase splicing and deprotection to obtain crude peptide; according to the strategy, the synthesis period can be remarkably shortened, large-scale industrial production is facilitated, meanwhile, the synthesis yield is high, and the purity and content of the obtained crude peptide are high.

Description

Technical Field

[0001] The present invention relates to the technical field of drug synthesis, and in particular to a method for synthesizing telpotide. Background Art

[0002] Tirzepatide is a dual-target agonist of GLP-1 and GIP developed by Eli Lilly. It was approved by the FDA for marketing in the United States in May 2022 to improve blood sugar in adults with type 2 diabetes (trade name Mounjaro); and in November 2023, it was approved by the US FDA for marketing as a weight loss drug (trade name Zepbound) for the treatment of obesity or overweight. In China, tirzepatide was approved for the treatment of type 2 diabetes and obesity in May and July 2024, respectively. In the first half of 2024 alone, the global sales of the drug reached US$6.658 billion, and continued to increase. The market demand for this drug is huge, and as of August 2024, it is still listed as a scarce drug by the FDA. Therefore, a faster and more efficient synthesis method is urgently needed to meet the huge market demand.

[0003] Its structure (peptide sequence): NH2-Tyr-Aib-Glu-Gly-Thr-Ser-Asp-Tyr-Ser-Ile-Aib-Leu-Asp-Lys-Ile-Ala-Asn-Lys(AEEA-AEEA-γ-Glu-eicosanedioic acid)-Ala-Phe-Val-Asn-Trp-Leu-Ile-Ala-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-CONH2.

[0004] Among them, AEEA is a special amino acid: 2-(2-(2-aminoethoxy)ethoxy)acetic acid.

[0005] The existing synthesis processes of telportin can be roughly divided into two categories:

[0006] The first type is Fmoc solid phase synthesis: this type of synthesis method is reported more frequently, including standard Fmoc solid phase, Lys removal of the protecting group and continued coupling synthesis of the side chain; and fragment condensation. All of them have the problem of long synthesis cycle or large loss.

[0007] The second type is the liquid phase splicing method: Eli Lilly and Company, in its patent application number CN113330024A, uses the liquid phase splicing method to synthesize telportipeptide, but the synthesis yield is relatively low.

[0008] It can be seen that it is very necessary to provide a synthesis method of tepote that can overcome the above problems. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides a method for synthesizing telpotide.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] The invention provides a method for synthesizing telpotide, which comprises firstly synthesizing fully protected peptide segments 1-17 and fully protected peptide segments 18-39 respectively, and then performing liquid phase splicing and deprotection treatment on the fully protected peptide segments 1-17 and the fully protected peptide segments 18-39 to obtain a crude telpotide peptide.

[0012] Furthermore, the method includes the following steps: 1) using 2-CTC resin as a solid phase carrier, using Fmoc solid phase synthesis strategy, sequentially coupling amino acids to obtain fully protected peptide resin 1-17, and the peptide resin 1-17 is subjected to soft cleavage to obtain fully protected peptide segment 1-17; 2) using Sieber resin as a solid phase carrier, using Fmoc solid phase synthesis strategy, sequentially coupling amino acids to obtain fully protected peptide resin 18-39, and the peptide resin 18-39 is subjected to soft cleavage to obtain fully protected peptide segment 18-39; 3) the fully protected peptide segment 1-17 and the fully protected peptide segment 18-39 are subjected to liquid phase splicing to obtain fully protected peptide 1-39, and then subjected to deprotection, sedimentation, washing and drying treatment to obtain the crude telport peptide.

[0013] Furthermore, the step 1) specifically includes: adding 2-CTC resin to a solid phase synthesis tube, adding DMF, and swelling the resin for 5 minutes; after 5 minutes, removing DMF, dissolving Fmoc-Ile-OH in DMF, adding DIPEA, reacting at room temperature for 2 hours, removing the solvent, and washing with DMF three times; deprotecting with 20% piperidine twice, each for 10 minutes, and washing with DMF six times; then condensing subsequent amino acids in sequence to obtain peptide resin 1-17; the peptide resin 1-17 is softly cleaved with 20% TFE / DCM for 2 hours, concentrated, precipitated, and dried to obtain the fully protected peptide segment 1-17.

[0014] Furthermore, the degree of substitution of the 2-CTC resin in step 1) is 0.5-1.3 mmol / g, preferably 0.9-1.2 mmol / g; optionally, the condensation agent combination used for condensation in step 1) is DIC / HOBt, Oxyma / DIC, PyBOP / HOBT / DIPEA, preferably DIC / HOBt.

[0015] Furthermore, the step 2) specifically includes: adding Sieber resin to a solid phase synthesis tube, adding DMF, and swelling the resin for 5 minutes; after 5 minutes, removing DMF, deprotecting twice with 20% piperidine, each time for 10 minutes, and washing with DMF six times; then condensing the subsequent amino acids in sequence to obtain peptide resin 18-39; wherein Fmoc-Lys(AEEA-AEEA-γ-Glu(α-OtBu)-eicosanedioic acid(mon-tBu))-OH is used at the K20 position; the peptide resin 18-39 is softly cleaved by 5% TFA / DCM for 2 hours, concentrated, precipitated, and dried to obtain the fully protected peptide segment 18-39.

[0016] Furthermore, the degree of substitution of the Sieber resin in step 2) is 0.3-0.9 mmol / g, preferably 0.5-0.8 mmol / g; optionally, the condensation agent combination used for condensation in step 2) is DIC / HOBt, Oxyma / DIC, PyBOP / HOBT / DIPEA, preferably DIC / HOBt.

[0017] Furthermore, the step 3) specifically includes: dissolving the fully protected peptide segments 1-17 and the fully protected peptide segments 18-39 in a reaction solvent, adding a condensation reagent, and after the room temperature reaction is completed, precipitating, filtering and drying to obtain the fully protected crude peptide 1-39; deprotecting, filtering, settling, washing and drying the fully protected crude peptide 1-39 to obtain the crude telportipeptide peptide.

[0018] Furthermore, in the step 3), the condensation reagent is PyBOP / HOBT / DIPEA, HATU / HOBT / DIPEA, TBTU / HOBT / DIPEA, HBTU / HOBT / DIPEA, preferably HBTU / HOBT / DIPEA.

[0019] Furthermore, the cleavage solution system used for deprotection in step 3) is TFA / TIPS / EDT / H2O=91 / 3 / 3 / 3, and the cleavage time is 2h; the sedimentation method in step 3) is to add 8 times the system of methyl tert-butyl ether into the reaction system, and the optional filtration method is filter cloth filtration.

[0020] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0021] The present invention provides a method for synthesizing Tirzepatide, and the method has at least three advantages: 1) the synthesis cycle is short, and two peptide segments can be synthesized simultaneously; 2) it is conducive to large-scale preparation, and compared with the Fmoc solid phase synthesis method, more peptide segments can be synthesized in a limited synthesis reactor volume; 3) the yield and purity of the obtained Tirzepatide are both high. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the structural formula of tepoxetine;

[0023] Figure 2 It is a synthetic route diagram of the synthetic method of telpotide provided by the present invention;

[0024] Figure 3 This is the HPLC spectrum of crude telpotide. DETAILED DESCRIPTION

[0025] The inventors have found that the synthesis method of tepote in the prior art has the following problems. The structural formula of tepote is as follows: Figure 1 shown.

[0026] The first type is the Fmoc solid phase synthesis method: 1) Patent CN113330024A: The standard Fmoc solid phase synthesis strategy was used to synthesize telopoietin, in which the Lys side chain at position 20 was protected by ivDde. Hydrazine hydrate was used to selectively remove Lys at position 20, and then (AEEA)2-γ-Glu-C 20 The method is limited by the long coupling time, which generally takes 4-8 hours for conventional amino acids and even up to 18 hours for special amino acids.

[0027] 2) Patents CN112592387B and CN114736271A use pseudo-pro dipeptide containing serine or glycine protected by Dmb as special materials for step-by-step coupling, which can effectively inhibit the shrinkage problem during peptide resin synthesis. However, after the condensation of glycine containing Dmb, the dipeptide defect at this site and the next site will be generated.

[0028] 3) Patents CN115651075B and CN110903355A use fragment (1-4) as the overall unit, intending to solve the difficulty in coupling amino acids 1 and 2. However, fragment (1-4) requires additional solid phase or liquid phase synthesis, which is cost-effective for large-scale production.

[0029] 4) Patents CN116120403A and CN115991742A use large fragments such as (1-16), (17-26), (27-39) or (1-14), (22-29) as splicing units. The disadvantages of this type of method are that large fragments require additional synthesis steps, and the amount of fragment peptides used in the solid phase is large, resulting in waste.

[0030] 5) Patents CN115181173A, CN115181174A and CN115160429A use 2-6 peptides or 5-7 peptides containing special sites, which can partially solve the defect problem. However, their shortcomings are also quite obvious: large fragments require additional synthesis steps, and the amount of fragment peptides used in the solid phase is large, resulting in waste.

[0031] The second type is the liquid phase splicing method: in the patent with application number CN113330024A, the four fully protected fragments of liquid phase splicing are fragment (1-14), fragment (15-21), fragment (22-29) and fragment (30-39). Fragment (22-29) and fragment (30-39) are spliced ​​in liquid phase and treated with nanofiltration equipment to obtain fragment (22-39); then fragment (22-39) and fragment (15-21) are subjected to liquid phase condensation and nanofiltration treatment to obtain fragment (15-39); finally, fragment (15-39) and fragment (1-14) are liquid phase condensed, and then deprotected to obtain a crude peptide. This method uses four peptide segments to be spliced ​​and coupled in sequence for synthesis, and the multi-step liquid phase condensation makes the final synthesis yield low.

[0032] From the above current process, we can see that the disadvantages of Fmoc solid phase stepwise synthesis are that the synthesis cycle is long and the scale-up is limited; in addition, the fragments used in the solid phase are generally 2-3 times excessive, resulting in large losses. Although Eli Lilly's four-fragment liquid phase splicing method can reduce the synthesis cycle, the multi-step liquid phase condensation makes the synthesis yield low.

[0033] In view of this, the present invention adopts a solid-liquid combination strategy to synthesize telportin. First, fully protected peptide segments (1-17) and (18-39) are synthesized separately, followed by liquid phase splicing and deprotection to obtain a crude peptide. This strategy can significantly shorten the synthesis cycle, is conducive to industrial large-scale production, and has a high synthesis yield, and the purity and content of the obtained crude peptide are also high.

[0034] The present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following peptide segments and peptide resins are all enclosed in brackets for easy understanding, and they refer to the same thing as the corresponding peptide segments and peptide resins in the claims.

[0035] The synthetic route diagram of the present invention is as follows Figure 2 shown.

[0036] The purpose of the present invention is to provide a fast and efficient Tirzepatide synthesis method. The method has a short synthesis cycle, high material utilization rate, and high final product yield and purity. The cost advantage is obvious and is conducive to large-scale industrial production.

[0037] Specifically, the present invention comprises the following steps.

[0038] 1) Using 2-CTC resin as a solid phase carrier and Fmoc solid phase synthesis strategy, amino acids are coupled in sequence to obtain a fully protected (1-17) peptide resin, and the peptide resin is softly cleaved to obtain a peptide segment (1-17);

[0039] 2) Using Sieber resin as a solid phase carrier and Fmoc solid phase synthesis strategy, amino acids are coupled in sequence to obtain a fully protected (18-39) peptide resin, and the peptide resin is softly cleaved to obtain the peptide segment (18-39);

[0040] 3) The fully protected peptide segments (1-17) and (18-39) are spliced ​​in liquid phase to obtain the fully protected peptide (1-39), which is then deprotected, precipitated, washed and dried to obtain the crude Tirzepatide peptide.

[0041] Specifically, the present invention comprises the following steps:

[0042] 1) Add 2-CTC resin to the solid phase synthesis tube, add DMF, and let the resin swell for 5 minutes. DMF was removed after 5 minutes, Fmoc-Ile-OH was dissolved in DMF, DIPEA was added, reacted at room temperature for 2 hours, the solvent was removed, and DMF was washed three times; 20% piperidine was deprotected twice, each time for 10 minutes, and DMF was washed six times; then the subsequent amino acids were condensed in sequence. The peptide resin was softly cleaved by 20% TFE / DCM for 2 hours, concentrated, precipitated, and dried to obtain the fully protected peptide segment (1-17).

[0043] 2) Add Sieber resin to the solid phase synthesis tube, add DMF, and let the resin swell for 5 minutes. After 5 minutes, remove DMF, deprotect with 20% piperidine twice, 10 minutes each time, and wash with DMF six times; then carry out the condensation of subsequent amino acids in sequence, where Fmoc-Lys(AEEA-AEEA-γ-Glu(α-OtBu)-eicosanedioic acid(mon-tBu))-OH is used at the K20 position. The peptide resin is softly cleaved with 5% TFA / DCM for 2 hours, concentrated, precipitated, and dried to obtain the fully protected peptide segment (18-39).

[0044] 3) Dissolve the peptide segment (1-17) and the peptide segment (18-39) in a reaction solvent, add a condensation reagent, and after the reaction is completed at room temperature, precipitate, filter, and dry to obtain a fully protected crude peptide (1-39).

[0045] 4) The fully protected peptide (1-39) is deprotected, filtered, precipitated, washed and dried to obtain crude Tirzepatide.

[0046] The degree of substitution of the 2-CTC resin in step 1) is 0.5 to 1.3 mmol / g, preferably 0.9 to 1.2 mmol / g.

[0047] In step 1), the condensing agent combination is DIC / HOBt, Oxyma / DIC, PyBOP / HOBT / DIPEA, preferably DIC / HOBt.

[0048] The degree of substitution of the Sieber resin in step 2) is 0.3 to 0.9 mmol / g, preferably 0.5 to 0.8 mmol / g.

[0049] In step 2), the condensing agent combination is DIC / HOBt, Oxyma / DIC, PyBOP / HOBT / DIPEA, among which DIC / HOBt is preferred.

[0050] In step 3), the condensing agent combination is PyBOP / HOBT / DIPEA, HATU / HOBT / DIPEA, TBTU / HOBT / DIPEA, HBTU / HOBT / DIPEA, among which HBTU / HOBT / DIPEA is preferred.

[0051] The lysis solution system in step 4) is TFA / TIPS / EDT / H2O=91 / 3 / 3 / 3. The lysis time is 2h.

[0052] In the step 4), the sedimentation method is to add 8 times of methyl tert-butyl ether into the reaction system, and the filtering method is to filter with filter cloth.

[0053] Example

[0054] 1. Tirzepatide synthesis

[0055] Example 1-1 (Synthesis of fully protected peptide segment (1-17))

[0056] 2-CTC Resin (8.70 g, 10 mmol) with a substitution degree of 1.15 mmol / g was selected and added to the reaction column, and swelled with DMF for 5 minutes. After 5 minutes, DMF was removed, Fmoc-Ile-OH (10.6 g, 30 mmol) was dissolved in DMF, DIPEA (5.2 mL, 30 mmol) was added, and the reaction was carried out at room temperature for 2 hours, and the solvent was removed, and washed with DMF three times; 20% piperidine was deprotected twice (10 minutes + 10 minutes), the solvent was removed, and the solvent was removed after washing with DMF six times.

[0057] Weigh Fmoc-Lys(Boc)-OH (14.1 g, 30 mmol) and HOBt (4.86 g, 36 mmol), add to the reaction column, dissolve in DMF, then add DIC (5.63 mL, 36 mmol), react at room temperature for 1 hour, detect the reaction with ninhydrin, filter, wash with an appropriate amount of DMF 5 times, and repeat the above operation to couple other amino acids and special materials. The reaction time of conventional amino acids is 1 hour. The coupling time of the special material Fmoc-Ile-Aib-OH is 5 hours, and the coupling time of Boc-Tyr(tBu)-Aib-OH is 3 hours. After all amino acids and special materials are coupled, add methyl tert-butyl ether shrink resin, and finally obtain 36.2 g of peptide resin:

[0058] Boc-Tyr(tBu)-Aib-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Tyr(tBu)-Ser(tBu)-Ile-Aib-Leu-Asp(OtBu)-Lys(Boc)-Ile-2CTC resin.

[0059] The specific coupling conditions are as follows:

[0060]

[0061]

[0062] Cleavage of fully protected peptide (1-17): Prepare cleavage solution (TFE: DCM = 20: 80, v / v) at a ratio of 10 mL / g peptide resin, mix well, add peptide resin to the reactor, then add cleavage solution, stir at 25±5°C for cleavage reaction, stir for 2 hours. Filter the resin, wash the resin with tertiary methyl ether and DCM alternately twice, drain, place the filtrate on a rotary evaporator to distill off DCM and trifluoroethanol, then add ethanol to continue distillation, distill until the material becomes a swollen solid, dissolve it with DMF (DMF amount is 4 times the synthesis scale), add 10 times the volume of DMF to the reactor, start stirring, then slowly add the material dropwise into the water, precipitate a white solid, continue stirring for 30 minutes after the addition is complete, filter, wash the filter cake with water 3 times, and drain.

[0063] Drying of the fully protected peptide (1-17): The product was placed in a forced air drying oven at 45°C and dried to constant weight. 27.1 g of the fully protected peptide (1-17) was collected, sealed, and stored at 2-8°C.

[0064] Example 1-2 (Synthesis of fully protected peptide segment (18-39))

[0065] Select Sieber Resin (13.3 g, 10 mmol) with a substitution degree of 0.75 mmol / g, add it to the reaction column, and swell with DMF for 5 minutes. DMF was removed after 5 minutes, 20% piperidine was used for deprotection twice (10 minutes + 10 minutes), the solvent was drained, and the solvent was removed after washing with DMF five times. Fmoc-Ser(tBu)-OH (11.5 g, 30 mmol) was dissolved in DMF, DIPEA (5.2 mL, 30 mmol) was added, and the reaction was carried out at room temperature for 2 hours, the solvent was removed, and the DMF was washed three times;

[0066] Weigh Fmoc-Pro-OH (10.1 g, 30 mmol) and HOBt (4.86 g, 36 mmol), add to the reaction column, dissolve in DMF, then add DIC (5.63 mL, 36 mmol), react at room temperature for 1 hour, detect the reaction with ninhydrin, filter, wash with an appropriate amount of DMF 5 times, and repeat the above operation to couple other amino acids and special materials. The reaction time of conventional amino acids is 1 hour. The coupling time of the special material Fmoc-Lys (AEEA-AEEA-γ-Glu (α-OtBu) -eicosanedioic acid (mon-tBu)) -OH is 5 hours. After all amino acids and special materials are coupled, add methyl tert-butyl ether shrink resin, and finally obtain 53.0 g of peptide resin:

[0067] NH2-Ala-Gln(Trt)-Lys(AEEA-AEEA-γ-Glu(α-OtBu)-eicosanedioic acid(mon-tBu))-Ala-Phe-Val-Gln(Trt)-Trp(Boc)-Leu-Ile-Ala-Gly-Gly-Pro-Ser(tBu)-Ser(tBu)-Gly-Ala-Pro-Pro-Pro-Ser(tBu)-Sieber resin.

[0068] The specific coupling conditions are as follows:

[0069]

[0070]

[0071] Cleavage of fully protected peptide (18-39): Prepare cleavage solution (TFA: DCM = 5: 95, v / v) at a ratio of 10 mL / g peptide resin, mix well, add peptide resin to the reactor, then add cleavage solution, stir at 25±5°C for cleavage reaction, stir for 2 hours. Filter the resin, wash the resin with DCM twice, drain, add the filtrate to sodium carbonate solution, stir for 15-20 min; separate the liquids, extract the aqueous phase with 4W2 mL DCM, collect the organic phases, dry over anhydrous sodium sulfate, filter, concentrate the filtrate, add it to n-heptane, precipitate the solid and filter.

[0072] Drying of the fully protected peptide (18-39): The product was placed in a forced air drying oven at 45°C and dried to constant weight. 38.5 g of the fully protected peptide (18-39) was collected, sealed, and stored at 2-8°C.

[0073] Example 1-3 (Synthesis of fully protected peptide segment (1-39))

[0074] The fully protected peptide (1-17) (8mmol, 1.0eq) and (18-39) (9.6mmol, 1.2eq) were sequentially added to 10V of the mass of the fully protected peptide (1-17) in DMF and stirred to dissolve, cooled to 0°C, and Cl-HOBt (12mmol, 1.5eq), DIPEA (64mmol, 8eq), and HATU (16mmol, 2.0eq) were sequentially added, stirred to dissolve, and then transferred to 25°C and stirred for 2h (HPLC was used to monitor whether the reaction was complete.) After the reaction was complete, the reaction solution was added dropwise to 5 times of DMF 15% citric acid water (precooled to 0°C), stirred and slurried at 25°C for 1h after the addition was completed, and then filtered. The filter cake was washed three times with purified water 10 times the mass of the fully protected peptide (1-17). The solid was transferred to a vacuum drying oven and dried at 45°C to constant weight to obtain 61.2g of the fully protected peptide (1-39).

[0075] Example 1-4 (Synthesis of crude telportin peptide)

[0076] Weigh 61.2g of fully protected peptide (1-39), the lysis solution system is TFA / TIPS / EDT / H2O=91 / 3 / 3 / 3. The amount of lysis solution is 490mL, and the lysis time is 2h. After the reaction is completed, cool to 0℃, slowly add 400mL of pre-cooled tert-methyl ether, and control the temperature below 10℃. After the addition is completed, stir at 5℃ for 1h, filter with 1000 mesh filter cloth, beat 100mL of tert-methyl ether 3 times, filter, and vacuum dry to finally obtain 38.7g of crude peptide product with a purity of 81.48%, such as Figure 3 shown.

[0077] Abbreviations and English meanings

[0078] Abbreviations and English meaning Fmoc 9-Fluorenylmethoxycarbonyl HOB 1-Hydroxybenzotriazole DIPEA N,N-Diisopropylethylamine PyBOP Benzotriazol-1-yl-oxytripyrrolidino hexafluorophosphate DMF N,N-Dimethylformamide TFA Trifluoroacetic acid EDT Ethanedithiol tBu Tert-butyl AEEA 2-(2-(2-aminoethoxy)ethoxy)acetic acid Dmb 2,4-Dimethoxybenzyl TIPS Triisopropylsilane Trt Trityl Boc tert-Butyloxycarbonyl OtBu Tert-butyl ester

[0079] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A method for synthesizing tepote, characterized in that: The method comprises firstly synthesizing fully protected peptide segments 1-17 and fully protected peptide segments 18-39 respectively, and then performing liquid phase splicing and deprotection treatment on the fully protected peptide segments 1-17 and the fully protected peptide segments 18-39 to obtain crude telpotide peptide.

2. The method for synthesizing telpotide according to claim 1, characterized in that: The method comprises the following steps: 1) Using 2-CTC resin as a solid phase carrier and Fmoc solid phase synthesis strategy, amino acids are coupled in sequence to obtain fully protected peptide resin 1-17, and the peptide resin 1-17 is softly cleaved to obtain fully protected peptide segment 1-17; 2) using Sieber resin as a solid phase carrier and using Fmoc solid phase synthesis strategy, sequentially coupling amino acids to obtain fully protected peptide resin 18-39, and soft cleavage of the peptide resin 18-39 to obtain fully protected peptide segment 18-39; 3) The fully protected peptide segments 1-17 and 18-39 are subjected to liquid phase splicing to obtain fully protected peptide 1-39, which is then subjected to deprotection, precipitation, washing and drying to obtain the crude telportipeptide peptide.

3. The method for synthesizing telpotide according to claim 2, characterized in that: The step 1) specifically includes: Add 2-CTC resin to a solid phase synthesis tube, add DMF, and let the resin swell for 5 minutes; remove DMF after 5 minutes, dissolve Fmoc-Ile-OH in DMF, add DIPEA, react at room temperature for 2 hours, remove the solvent, and wash three times with DMF; deprotect twice with 20% piperidine, each time for 10 minutes, and wash six times with DMF; then condense the subsequent amino acids in sequence to obtain peptide resin 1-17; the peptide resin 1-17 is softly cleaved with 20% TFE / DCM for 2 hours, concentrated, precipitated, and dried to obtain the fully protected peptide segment 1-17.

4. The method for synthesizing telpotide according to claim 3, characterized in that: The degree of substitution of the 2-CTC resin in step 1) is 0.5 to 1.3 mmol / g, preferably 0.9 to 1.2 mmol / g; Optionally, the condensing agent combination used for condensation in step 1) is DIC / HOBt, Oxyma / DIC, PyBOP / HOBT / DIPEA, preferably DIC / HOBt.

5. The method for synthesizing telpotide according to claim 2, characterized in that: The step 2) specifically includes: Sieber resin was added to a solid phase synthesis tube, and DMF was added, and the resin was swollen for 5 minutes; after 5 minutes, DMF was removed, and 20% piperidine was used for deprotection twice, each time for 10 minutes, and DMF was washed six times; then, subsequent amino acids were condensed in sequence to obtain peptide resin 18-39; Fmoc-Lys(AEEA-AEEA-γ-Glu(α-OtBu)-eicosanedioic acid(mon-tBu))-OH was used at the K20 position; the peptide resin 18-39 was softly cleaved by 5% TFA / DCM for 2 hours, concentrated, precipitated, and dried to obtain the fully protected peptide segment 18-39.

6. The method for synthesizing telpotide according to claim 5, characterized in that: The degree of substitution of the Sieber resin in step 2) is 0.3 to 0.9 mmol / g, preferably 0.5 to 0.8 mmol / g; Optionally, the condensing agent combination used for condensation in step 2) is DIC / HOBt, Oxyma / DIC, PyBOP / HOBT / DIPEA, preferably DIC / HOBt.

7. The method for synthesizing telpotide according to claim 2, characterized in that: The step 3) specifically includes: Dissolve the fully protected peptide segments 1-17 and 18-39 in a reaction solvent, add a condensation reagent, and after the reaction is completed at room temperature, precipitate, filter, and dry to obtain a fully protected crude peptide 1-39; The fully protected crude peptide 1-39 is deprotected, filtered, precipitated, washed and dried to obtain the crude telpotide peptide.

8. The method for synthesizing telpotide according to claim 7, characterized in that: In the step 3), the condensation reagent is PyBOP / HOBT / DIPEA, HATU / HOBT / DIPEA, TBTU / HOBT / DIPEA, HBTU / HOBT / DIPEA, preferably HBTU / HOBT / DIPEA.

9. The method for synthesizing telpotide according to claim 7, characterized in that: The cleavage solution system used for deprotection in step 3) is TFA / TIPS / EDT / H2O=91 / 3 / 3 / 3, and the cleavage time is 2h; In the step 3), the sedimentation method is to add 8 times of methyl tert-butyl ether into the reaction system, and the optional filtering method is filtering with filter cloth.

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