A method for synthesizing a cyclic peptide compound and application thereof

Abstract

This invention relates to a method for synthesizing cyclic peptide compounds and their applications. Specifically, this invention provides a method for reacting a compound of formula (I) as a substrate in the presence of copper acetate and phenanthroline to obtain a cyclic peptide compound of formula (II). The preparation method has the advantages of mild conditions, simple operation, and wide applicability.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, specifically to a method for synthesizing cyclic peptide compounds and its applications. Background Technology

[0002] Imidazoles are common key pharmacophores in medicinal chemistry, especially in small molecule drugs, and their introduction into peptides may offer potential benefits, such as improved protease stability and enhanced biological activity. However, while imidazoles are widely used as building blocks or directing groups in small molecule organic chemistry, their application in peptide modification is rarely reported due to considerations such as site specificity, compatibility, chemoselectivity, and maintaining peptide integrity.

[0003] The Cu-catalyzed Chan-Lam reaction, first discovered in 1998, is a landmark method for constructing sp2-CN bonds through oxidative CN cross-coupling. This reaction has proven compatible with a wide range of functional groups, including amines, amides, sulfonamides, imidazoles, tetrazolium, and phenols, demonstrating its versatility. Therefore, the Chan-Lam reaction has been widely applied in the development of active pharmaceutical ingredients (APIs) and has had a significant impact on the development of small molecule drugs. In 2018, Ball and colleagues developed a groundbreaking bisorthogonal Chan-Lam coupling on a pyroglutamic acid-histidine dipeptide sequence using histidine as a directing group. More recently, Dang and colleagues have used the Chan-Lam reaction to site-specifically introduce a corresponding group into a specially designed peptide containing histidine at a specific position. In this case, the imidazole side chain of histidine acts as an anchoring group, co-coordinating with Cu(II) and Asp, Asn, or Ser. These strategies require the deliberate use of histidine-containing metal-binding tags in peptides / proteins to achieve effective coupling. It remains uncertain whether imidazole-containing compounds can serve as a universal bridge for site-specific peptide modification. Developing site-specific peptide modification tools based on imidazole could facilitate the creation of novel bioactive conjugates, cyclic peptides, and more. Summary of the Invention

[0004] The problem the invention aims to solve

[0005] To address the aforementioned problems in the prior art, this invention provides a mild coupling method using derivatives containing borate-treated side chains and imidazoles as substrates, under the combined action of copper acetate and phenanthroline, which can be used for site-specific synthesis and modification of cyclic peptide compounds.

[0006] Solution for solving the problem

[0007] A method for preparing the compound shown in formula (II), characterized in that the compound shown in formula (I) reacts in the presence of copper acetate and phenanthroline to obtain the compound shown in formula (II).

[0008]

[0009] Wherein, R1 is a hydrogen or amino protecting group;

[0010] R2 is a polypeptide sequence;

[0011] R3 is a hydroxyl or carboxyl protecting group.

[0012] Preferably, the method is carried out in the presence of a solvent, wherein the solvent is selected from one or more of MeOH, DMF, DCM, MeCN, i-PrOH, EtOH, DMA and THF.

[0013] Preferably, the solvent is selected from one or more of MeOH, MeCN, and EtOH.

[0014] More preferably, the solvent is selected from MeOH.

[0015] Preferably, the method is carried out in the presence of a base, wherein the base is selected from organic or inorganic bases.

[0016] Preferably, the organic base is selected from one or more of TEA, DIPEA, DABCO, TEMED, MeONa, t-BuOK, 2,6-Lutidine, and Py.

[0017] More preferably, the organic base is selected from one or more of TEA, DIPEA, TEMED and MeONa.

[0018] Preferably, the inorganic base is selected from one or more of NaHCO3, Na2CO3, and K3PO4.

[0019] More preferably, the inorganic base is selected from NaHCO3.

[0020] Preferably, the polypeptide sequence is composed of linked amino acid residues.

[0021] Preferably, the amino acid is selected from one or more of the substituted or unsubstituted Tyr, Ala, Val, Leu, Ile, Met, Phe, Pro, Lys, Trp, Asp, Gly, Ser, Glu, Thr, and His.

[0022] More preferably, the amino acid is selected from one or more of Tyr, Asp, Ala, Ser, His, Leu, Met, Phe, and Pro, whether substituted or unsubstituted.

[0023] The substitution is performed by at least one substituent selected from amino or Boc.

[0024] Preferably, the length of the polypeptide sequence is 1 to 39 amino acids.

[0025] More preferably, the length of the polypeptide sequence is 1 to 20 amino acids.

[0026] Most preferably, the length of the polypeptide sequence is 1 to 10 amino acids.

[0027] Preferably, the amino protecting group is Ac, Boc, Moz, or Fmoc.

[0028] Preferably, the carboxyl protecting group is amino, tert-butoxy, methoxy, or ethoxy.

[0029] Preferably, the compound represented by formula (I) is the compound represented by formula (I-1):

[0030]

[0031] More preferably, the compound represented by formula (I-1) is selected from any one of the following:

[0032]

[0033] Preferably, the molar ratio of copper acetate to phenanthroline is 1:0.5 to 3, and more preferably 1:0.5 to 2.

[0034] Preferably, the molar ratio of the compound represented by formula (I) to the copper acetate is 1 to 5:1, more preferably 1 to 3:1. Preferably, the reaction temperature is 35 to 45°C, and the reaction time is 15 to 35 hours.

[0035] The effects of the invention

[0036] In the method of this invention, a Chan-Lam reaction is carried out using the boric acid derivative shown in Formula (I) as a substrate, under the combined action of copper acetate and phenanthroline, to achieve site-specific modification of the peptide compound and form a cyclic peptide compound. In the method provided by this invention, the imidazole group in the boric acid derivative shown in Formula (I) exhibits unique selectivity for various unprotected amino acid side chains (excluding cysteine ​​and arginine), providing a new strategy for the construction of novel cyclic peptide molecules, thereby obtaining a variety of novel peptide-drug conjugates (PDCs). Furthermore, the reaction method provided by this invention can precisely adjust the physicochemical properties of peptides, such as the stability and cell membrane permeability of the peptide compound.

[0037] The preparation method provided by this invention has a low reaction temperature and high yield; this method can be applied to site-specific modification of peptide chains of different lengths and has wide applicability; the method provided by this invention has good chemoselectivity and potential for application in peptide modification, and has broad application value. Attached Figure Description

[0038] Figure 1 The ESI spectrum of compound 1 is shown below.

[0039] Figure 2 The ESI spectrum of compound 2;

[0040] Figure 3 The ESI spectrum of compound 3;

[0041] Figure 4 The image shows the ESI spectrum of compound 4. Detailed Implementation

[0042] To make the technical solution and beneficial effects of the present invention more apparent and understandable, a detailed description is provided below by listing specific embodiments. The accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.

[0043] Late-stage site-specific modification of peptides plays a crucial role in the coupling of bioactive molecules and drug development, and there is still a need to develop chemical methods that can achieve site-specific modification of peptides under milder conditions. Through extensive and in-depth research, the inventors have developed a site-specific late-stage modification strategy for cyclic peptides based on the Chan-Lam coupling reaction. Unlike existing technologies, this invention utilizes the mild reaction conditions of Chan-Lam coupling and the unique nucleophilicity of the imidazole group in boric acid derivatives to develop a novel modification strategy for cyclic peptide compounds. Based on this, this invention has been completed.

[0044] A method for preparing the compound shown in formula (II), characterized in that the compound shown in formula (I) reacts in the presence of copper acetate and phenanthroline to obtain the compound shown in formula (II).

[0045]

[0046] Wherein, R1 is a hydrogen or amino protecting group;

[0047] R2 is a polypeptide sequence;

[0048] R3 is a hydroxyl or carboxyl protecting group.

[0049] In some embodiments, the method is carried out in the presence of a solvent selected from one or more of MeOH, DMF, DCM, MeCN, i-PrOH, EtOH, DMA, and THF.

[0050] In some embodiments, the solvent is selected from one or more of MeOH, MeCN, and EtOH.

[0051] In some embodiments, the solvent is selected from MeOH.

[0052] In some embodiments, the method is carried out in the presence of a base, which is selected from organic or inorganic bases.

[0053] In some embodiments, the organic base is selected from one or more of TEA, DIPEA, DABCO, TEMED, MeONa, t-BuOK, 2,6-Lutidine, and Py.

[0054] In some embodiments, the organic base is selected from one or more of TEA, DIPEA, TEMED, and MeONa;

[0055] In some embodiments, the inorganic base is selected from one or more of NaHCO3, Na2CO3, and K3PO4.

[0056] In some embodiments, the inorganic base is selected from NaHCO3.

[0057] In some embodiments, the polypeptide sequence is formed by linking amino acid residues;

[0058] In some embodiments, the amino acid is selected from one or more of the substituted or unsubstituted Tyr, Ala, Val, Leu, Ile, Met, Phe, Pro, Lys, Trp, Asp, Gly, Ser, Glu, Thr, and His.

[0059] In some embodiments, the amino acid is selected from one or more of the substituted or unsubstituted Tyr, Asp, Ala, Ser, His, Leu, Met, Phe, and Pro.

[0060] The substitution is performed by at least one substituent selected from amino or Boc.

[0061] In some embodiments, the length of the polypeptide sequence is 1 to 39 amino acids, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, etc.

[0062] In some embodiments, the length of the polypeptide sequence is 1 to 20 amino acids.

[0063] In some embodiments, the length of the polypeptide sequence is 1 to 10 amino acids.

[0064] In some embodiments, the length of the polypeptide sequence is 3, 4, 5, 6, 7 or 8 amino acids.

[0065] In some embodiments, the amino protecting group is Ac, Boc, Moz, or Fmoc.

[0066] In some embodiments, the amino protecting group is Ac.

[0067] In some embodiments, the carboxyl protecting group is amino, tert-butoxy, methoxy, or ethoxy. In some embodiments, the carboxyl protecting group is NH2.

[0068] In some embodiments, the compound represented by formula (I) is the compound represented by formula (I-1):

[0069]

[0070] In some embodiments, the compound represented by formula (I-1) is selected from any of the following:

[0071]

[0072]

[0073] In a preferred embodiment, the compound represented by formula (I-1) is selected from any of the following:

[0074]

[0075]

[0076] In some embodiments, the molar ratio of copper acetate to phenanthroline is 1:0.5 to 3, for example, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc.

[0077] In some embodiments, the molar ratio of copper acetate to phenanthroline is 1:0.5 to 2.

[0078] In some embodiments, the molar ratio of copper acetate to phenanthroline is 1:1.

[0079] In some embodiments, the molar ratio of the compound represented by formula (I) to the copper acetate is 1 to 5:1, for example 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1.

[0080] In some embodiments, the molar ratio of the compound represented by formula (I) to the copper acetate is 1 to 3:1.

[0081] In some embodiments, the molar ratio of the compound represented by formula (I) to the copper acetate is 1.5 to 2.5:1.

[0082] In some embodiments, the molar ratio of the compound represented by formula (I) to the copper acetate is 2:1.

[0083] In some embodiments, the molar ratio of the compound represented by formula (I) to the base is 1:2 to 6, for example 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, etc.

[0084] In some embodiments, the molar ratio of the compound represented by formula (I) to the base is 1:3 to 5.

[0085] In some embodiments, the reaction temperature is 35–45°C (e.g., 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, etc.), and the reaction time is 15–35 hours (e.g., 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, 31 hours, 32 hours, 33 hours, 34 hours, 35 hours, etc.).

[0086] Terminology Explanation

[0087] Unless otherwise stated, the terms used in the specification and claims have the following meanings.

[0088] The term "amino acid" refers to a molecule containing an amino and a carboxylic acid group and optionally one or more additional groups, often referred to as side chains. The amino acids in the compound sequences described in this invention are derived from natural amino acids or related amino acid variants and / or derivatives. The abbreviations and codes of the natural amino acids follow generally accepted rules well known to those skilled in the art. Amino acids are typically coded using standard single letters (e.g., L = leucine) and α-methyl substituted residues of the natural amino acid (e.g., α-methylleucine, or αMeL). Unless explicitly stated otherwise, all amino acid residues of this invention are preferably in the L-configuration, but the D-configuration also applies, for example, dS represents D-type Ser.

[0089] Amino acids, their abbreviations, and English abbreviations are shown in Table 1:

[0090] Table 1

[0091] name Three-letter abbreviation single-letter abbreviations alanine Ala A Aspartic acid Asp D glutamic acid Glu E Phenylalanine Phe F glycine Gly G Isoleucine Ile I Lysine Lys K Leucine Leu L proline Pro P glutamine Gln Q Serine Ser S threonine Thr T Tyrosine Tyr Y Histidine His H

[0092] In this article, when referring to peptides, "amino acid" and "amino acid residue" have the same meaning, referring to the amino acid residues that remain after some groups are lost due to their participation in the formation of the linking bond when amino acids are linked by chemical bonds.

[0093] The term "peptide" refers to a sequence of two or more amino acids. "Peptide" can also include amino acid elongations at the N-terminus and / or C-terminus, and / or truncations at the N-terminus and / or C-terminus. Typically, amino acid residues are represented by their full name, their single-letter code, and / or their three-letter code. These three methods are completely equivalent.

[0094] The term "protecting group" refers to a group that selectively blocks one reactive site of a multifunctional compound so that the chemical reaction selectively proceeds at another unprotected reactive site (meaning the one usually associated with in synthetic chemistry).

[0095] The term "carboxyl protecting group" refers to a substituent of the carboxyl group used to block or protect the functionality of the carboxyl group, which can be converted into a carboxyl protecting group through hydrolysis or deprotection reaction. The carboxyl protecting group is preferably alkyl (e.g., methyl, ethyl, tert-butyl) or aralkyl (e.g., benzyl), more preferably amino, tert-butoxy, methoxy, or ethoxy. In this invention, "protected carboxyl group" refers to the group formed after the carboxyl group is protected by a suitable carboxyl protecting group, preferably methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl, or benzyloxycarbonyl. The carboxyl protecting group can be removed by hydrolysis under acid or base catalysis, and occasionally by thermal decomposition. For example, tert-butyl can be removed under mild acidic conditions, and benzyl can be removed by hydrogenolysis. The reagent for removing the carboxyl protecting group is selected from TFA, H2O, LiOH, NaOH, KOH, MeOH, EtOH, and combinations thereof, preferably a combination of TFA and H2O, a combination of LiOH and MeOH, or a combination of LiOH and EtOH. The protected carboxyl group is deprotected to produce the corresponding free acid, the deprotection is carried out in the presence of a base, and the base and the free acid formed by the deprotection form a pharmaceutically acceptable salt.

[0096] In this invention, "amino protecting group" is equivalent to "amine protecting group" and includes all groups that can be used as protecting groups for ordinary amino / amine groups, such as aryl C. 1-6 Alkyl, C 1-6 Alkoxy C 1-6 Alkyl, C 1-6 Alkoxycarbonyl, aryloxycarbonyl, C 1-6 Alkyl sulfonyl, aryl sulfonyl, or silyl groups are preferred. The amino protecting group is preferably Ac (acetyl), Boc (tert-butyloxycarbonyl), Moz (p-methoxybenzyloxycarbonyl), or Fmoc (9-fluorenemethoxycarbonyl). The reagent for removing the amino protecting group is selected from TFA, H2O, LiOH, MeOH, EtOH, and combinations thereof, preferably combinations of TFA and H2O, LiOH and MeOH, or LiOH and EtOH. The reagent for removing Boc protection is TFA or HCl / EA; TFA is preferred. The deprotecting agent used for removing Fmoc protection is a solution of N,N-dimethylformamide (DMF) containing 20% ​​piperidine.

[0097] The term "hydroxyl group" refers to -OH.

[0098] The term "amino" refers to -NH2.

[0099] The term "carboxyl group" refers to -C(O)OH.

[0100] "Optional" or "optionally" means that the event or environment described below may but does not have to occur, and the description includes the possibility or absence of the event or environment. For example, "optionally alkyl-substituted heterocyclic group" means that the alkyl group may but does not have to be present, and the description includes cases where the heterocyclic group is substituted with an alkyl group and cases where the heterocyclic group is not substituted with an alkyl group.

[0101] "Substituted" refers to one or more hydrogen atoms in a group, preferably 1 to 5, more preferably 1 to 3 hydrogen atoms, which are independently substituted by the corresponding number of substituents. Those skilled in the art can determine possible or impossible substitutions without much effort (through experimentation or theory). For example, an amino or hydroxyl group with free hydrogen may be unstable when combined with a carbon atom having an unsaturated bond (such as an alkene).

[0102] In this application, the term "reaction yield" refers to the product yield calculated by detecting the product concentration in the reaction solution using LC-MS before product purification after the reaction is completed.

[0103] The method of the present invention will be described below through specific embodiments. It should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0104] The following examples 1 The 1H NMR spectra were obtained using a Bruker instrument (400 MHz), and chemical shifts are expressed in ppm. Tetramethylsilane internal standard (0.00 ppm) was used. 1 HNMR representation: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broadened, dd = doublet of doublet, dt = doublet of triplet. If the coupling constant is provided, the unit is Hz.

[0105] The mass spectrometry results were obtained using an LC / MS instrument, with ESI as the ionization method.

[0106] High-performance liquid chromatograph (HPLC) models: Agilent 1260, Thermo Fisher U3000; Column model: Waters xbrige C18 (4.6*150mm, 3.5μm); Mobile phase: A: ACN, B: Water (0.1% H3PO4); Flow rate: 1.0 mL / min; Gradient: 5% A for 1 min, increase to 20% A within 4 min, increase to 80% A within 8 min, 80% A for 2 min, back to 5% A within 0.1 min; Wavelength: 220 nm; Column oven: 35℃.

[0107] TLC: Thin-layer chromatography. Yantai Huanghai HSGF254 or Qingdao GF254 silica gel plates are used for TLC. The silica gel plates used in TLC have a diameter of 0.2mm-0.3mm, while those used for separating and purifying products are 0.4mm-0.5mm.

[0108] Column chromatography typically uses Yantai Huanghai silica gel with a mesh size of 200-300 as the carrier.

[0109] In the following examples, unless otherwise specified, all temperatures are in Celsius; unless otherwise specified, all starting materials and reagents are commercially available or synthesized according to known methods; commercially available materials and reagents are used directly without further purification; unless otherwise specified, commercially available manufacturers include, but are not limited to, Sinopharm Group, Bailingwei Technology Co., Ltd., TCI (Shanghai) Chemical Industry Development Co., Ltd., Shanghai Bid Pharmaceutical Technology Co., Ltd., and Shanghai Mairui Chemical Technology Co., Ltd.

[0110] Unless otherwise specified in the examples, the solution in the reaction refers to an aqueous solution.

[0111] Unless otherwise specified in the examples, the reaction temperature is room temperature, which is 20℃-30℃.

[0112] The reaction process in the examples was monitored using thin-layer chromatography (TLC). The developing solvent used in the reaction, the eluent system used for column chromatography to purify the compounds, or the developing solvent system for TLC included: A: petroleum ether and ethyl acetate system; B: dichloromethane and methanol system; C: n-hexane: ethyl acetate. The volume ratio of the solvent varied depending on the polarity of the compound and could also be adjusted by adding a small amount of acidic or basic reagents, such as acetic acid or triethylamine.

[0113] Example 1

[0114]

[0115] Under open conditions, a stir bar, boric acid derivative 1 (0.05 mmol, 1 equivalent), copper acetate (0.025 mmol, 0.5 equivalent), phenanthroline (0.025 mmol, 0.5 equivalent), and 2 mL of methanol were added to a 4 mL glass flask. After stirring for 3 minutes, 4 equivalents of DIPEA were added, and the reaction was carried out at 40 °C for 24 hours. The reaction was monitored by LC-MS. After the reaction was completed, the solvent was removed by rotary evaporation, and the product was purified by preparative HPLC (using water and acetonitrile containing 1 / 1000 trifluoroacetic acid as the mobile phase).

[0116] In this embodiment, the reaction yield of compound 1 was 36%, and the mass spectrometry data were: C 36 H 51 N9O8S 770.3654[M+H] + 1539.7235[2M+H] + The values ​​were found to be 770.3494 and 1539.6936. The mass spectrum of compound 1 prepared in this example is shown below. Figure 1 As shown.

[0117] Example 2

[0118]

[0119] Following the preparation method of Example 1, and according to the amino acid sequence of compound 2 (Ac-Phe B Compound 2 was prepared using the reaction mixture (-Ser-Ala-Pro-Leu-Ala-His-NH2), the difference being the different starting materials. In this example, the reaction yield of the compound was 49%, and the mass spectrometry data were as follows: Molecular weight calculated as: C 37 H 52 N 10 O9781.3991[M+H] + 1561.7910[2M+H] + The mass spectrum of compound 2 prepared in this embodiment is shown below, with values ​​of 770.3858 and 1561.7543 found. Figure 2 As shown.

[0120] Example 3

[0121]

[0122] Following the preparation method of Example 1, and according to the amino acid sequence of compound 3 (Ac-Phe B Compound 3 was prepared using Phe-Pro-Asp-Tyr-Ala-His-NH2, the difference being the different starting materials. In this example, the reaction yield of the compound was 32%, and the mass spectrometry data were as follows: Molecular weight was calculated as: C 47 H 54 N10 O 11 935.4046[M+H] + Find 935.3856. The mass spectrum of compound 3 prepared in this embodiment is as follows. Figure 3 As shown.

[0123] Example 4

[0124]

[0125] Following the preparation method of Example 1, and according to the amino acid sequence of compound 4 (Ac-Phe B Compound 4 was prepared using Leu-Asp-Pro-Ala-Ser-Ala-His-NH2, the difference being the different starting materials. In this example, the reaction yield of the compound was 29%, and the mass spectrometry data were as follows: Molecular weight was calculated to be: C 41 H 57 N 11 O 12 896.4261[M+H] + 1791.8449[2M+H] + Find 896.4074, 1791.8069. The mass spectrum of compound 4 prepared in this example is as follows. Figure 4 As shown.

[0126] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of the present invention and do not limit the scope of protection of this patent.

Claims

1. A method for preparing the compound shown in formula (II), characterized in that, The compound shown in formula (I) reacts in the presence of copper acetate and phenanthroline to give the compound shown in formula (II). ； Wherein, R1 is a hydrogen or amino protecting group; R2 is a polypeptide sequence; the polypeptide sequence is composed of amino acid residues linked together, and the length of the polypeptide sequence is 1 to 20 amino acids. R3 is a hydroxyl or carboxyl protecting group.

2. The method according to claim 1, characterized in that, The method involves a reaction in the presence of a solvent, wherein the solvent is selected from MeOH, DMF, DCM, MeCN, etc. i One or more of -PrOH, EtOH, DMA and THF.

3. The method according to claim 2, characterized in that, The solvent is one or more of MeOH, MeCN, and EtOH.

4. The method according to claim 3, characterized in that, The solvent is selected from MeOH.

5. The method according to claim 1, characterized in that, The method involves a reaction in the presence of a base, which is selected from organic or inorganic bases.

6. The method according to claim 5, characterized in that, The organic base is selected from TEA, DIPEA, DABCO, TEMED, MeONa, etc. t One or more of -BuOK, 2,6-Lutidine, and Py.

7. The method according to claim 6, characterized in that, The organic base is selected from one or more of TEA, DIPEA, TEMED, and MeONa.

8. The method according to claim 5, characterized in that, The inorganic base is selected from one or more of NaHCO3, Na2CO3, and K3PO4.

9. The method according to claim 8, characterized in that, The inorganic base is selected from NaHCO3.

10. The method according to claim 1, characterized in that, The amino acid is selected from one or more of the substituted or unsubstituted Tyr, Ala, Val, Leu, Ile, Met, Phe, Pro, Lys, Trp, Asp, Gly, Ser, Glu, Thr, and His; the substitution is by at least one substituent selected from amino or Boc.

11. The method according to claim 10, characterized in that, The amino acid is selected from one or more of Tyr, Asp, Ala, Ser, His, Leu, Met, Phe, and Pro.

12. The method according to claim 1, characterized in that, The length of the polypeptide sequence is 1 to 10 amino acids.

13. The method according to claim 1, characterized in that, The amino protecting group is Ac, Boc, Moz, or Fmoc.

14. The method according to claim 1, characterized in that, The carboxyl protecting group is amino, tert-butoxy, methoxy, or ethoxy.

15. The method according to claim 1, characterized in that, The compound represented by formula (I) is the same as the compound represented by formula (I-1): 。 16. The method according to claim 15, characterized in that, The compound represented by formula (I-1) is selected from any of the following: 、 、 、 。 17. The method according to claim 1, characterized in that, The molar ratio of copper acetate to phenanthroline is 1:0.5~3.

18. The method according to claim 17, characterized in that, The molar ratio of copper acetate to phenanthroline is 1:0.5~2.

19. The method according to claim 1, characterized in that, The molar ratio of the compound shown in formula (I) to the copper acetate is 1 to 5:

1.

20. The method according to claim 19, characterized in that, The molar ratio of the compound shown in formula (I) to the copper acetate is 1 to 3:

1.

21. The method according to claim 1, characterized in that, The reaction temperature is 35~45℃, and the reaction time is 15~35 hours.

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