Synthesis method and application of cyclic peptide compound

Abstract

The invention relates to a synthetic method and application of a cyclic peptide compound. Specifically, the cyclopeptide compound shown in the formula (II) is obtained by reacting a compound shown in the formula (I) serving as a substrate in the presence of copper acetate and phenanthroline, and the preparation method has the advantages of mild conditions, simplicity and convenience in operation, wide application range and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and in particular to a method for synthesizing a cyclic peptide compound and an application thereof. Background Art

[0002] Imidazole is a common key pharmacophore in medicinal chemistry, especially in small molecule drugs, and therefore may provide potential benefits when introduced into peptides, such as improved protease stability and enhanced biological activity. However, imidazole is widely used as a building block or directing group in small molecule organic chemistry, but has rarely been reported in the modification of peptides due to issues such as site specificity, compatibility, chemical selectivity, and maintaining peptide integrity.

[0003] The Cu-catalyzed Chan-Lam reaction, first discovered in 1998, is a landmark method for constructing sp2 CN bonds via oxidative CN cross-coupling. The reaction has been shown to be compatible with a variety of functional groups, including amines, amides, sulfonamides, imidazoles, tetrazoles, and phenols, demonstrating its versatility. As a result, the Chan-Lam reaction has been widely used in the development of active pharmaceutical ingredients (APIs) and has had a significant impact on the development of small molecule drugs. In 2018, Ball et al. developed a groundbreaking biorthogonal Chan-Lam coupling on a pyroglutamic acid-histidine dipeptide sequence using histidine as a directing group. More recently, Dang et al. used the Chan-Lam reaction to site-directedly introduce the corresponding group in a specially designed peptide containing histidine at a specific position. In this case, the imidazole side chain of histidine acts as an anchoring group to coordinate 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 conjugation. It is still uncertain whether imidazole-containing compounds can serve as a universal bridge for site-specific peptide modification. The development of site-specific peptide modification tools using imidazole as a substrate can promote the creation of new bioactive conjugates, cyclic peptides, etc. Summary of the invention

[0004] Problem that the invention aims to solve

[0005] In order to solve the above problems existing in the prior art, the present invention provides a mild coupling method under the joint action of copper acetate and phenanthroline, using a derivative containing an acid-borated side chain and imidazole as a substrate, which can be used for site-specific synthesis and modification of cyclic peptide compounds.

[0006] Solutions for solving problems

[0007] A method for preparing a compound represented by formula (II), characterized in that the compound represented by formula (I) is reacted in the presence of copper acetate and phenanthroline to obtain a compound represented by formula (II),

[0008]

[0009] Among them, R 1 is hydrogen or an amino protecting group;

[0010] R 2 is a polypeptide sequence;

[0011] R 3 It is a hydroxy or carboxyl protecting group.

[0012] Preferably, the method is carried out in the presence of a solvent, and 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, and the base is selected from an organic base or an inorganic base.

[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 NaHCO 3 、Na 2 CO 3 , K 3 PO 4 One or more of .

[0019] More preferably, the inorganic base is selected from NaHCO 3 .

[0020] Preferably, the polypeptide sequence is formed by connecting amino acid residues.

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

[0023] The substitution is substituted with 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 a 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 the copper acetate to the phenanthroline is 1:0.5-3, preferably 1:0.5-2.

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

[0035] Effects of the Invention

[0036] In the method of the present invention, a Chan-Lam reaction is performed under the combined action of copper acetate and phenanthroline using a boronic acid derivative shown in formula (I) as a substrate to achieve site-specific modification in a polypeptide compound to form a cyclic peptide compound. In the method provided by the present invention, the imidazole group in the boronic acid derivative shown in formula (I) has a unique selectivity for a variety of unprotected amino acid side chains (excluding cysteine ​​and arginine), providing a new strategy for the construction of new cyclic peptide molecules, thereby obtaining a variety of new peptide-drug conjugates (PDCs), and the reaction method provided by the present invention can accurately adjust the physicochemical properties of peptides, for example, the stability of polypeptide compounds and cell membrane permeability.

[0037] The preparation method provided by the present invention has mild reaction conditions and high yield; the method can be applied to site-specific modification of peptide chains of different lengths and has wide applicability; the method provided by the present invention has good chemical selectivity and potential for application in the modification of polypeptides and has wide application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the ESI spectrum of compound 1;

[0039] Figure 2 is the ESI spectrum of compound 2;

[0040] Figure 3 is the ESI spectrum of compound 3;

[0041] Figure 4 This is the ESI spectrum of compound 4. DETAILED DESCRIPTION

[0042] In order to make the technical solutions and beneficial effects of the present invention more clearly understandable, the following is a detailed description by listing specific embodiments. The 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 belongs.

[0043] The late site-specific modification of peptides plays a key role in the coupling of bioactive molecules and drug development, and it is still necessary to develop chemical methods that can achieve site-specific modification of peptides under milder conditions. After extensive and in-depth research, the inventors have developed a site-specific late modification strategy for cyclic peptides based on the Chan-Lam coupling reaction. Different from the prior art, the present invention utilizes the mild reaction conditions of the Chan-Lam coupling and the unique nucleophilicity of the imidazole group in the boronic acid derivative to develop a new modification strategy for cyclic peptide compounds. Based on this, the present invention is completed.

[0044] A method for preparing a compound represented by formula (II), characterized in that the compound represented by formula (I) is reacted in the presence of copper acetate and phenanthroline to obtain a compound represented by formula (II),

[0045]

[0046] Among them, R 1 is hydrogen or an amino protecting group;

[0047] R 2 is a polypeptide sequence;

[0048] R 3 It is a hydroxy or carboxyl protecting group.

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

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

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

[0052] In certain embodiments, the method is performed in the presence of a base, and the base is selected from an organic base or an inorganic base.

[0053] In certain 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 certain embodiments, the organic base is selected from one or more of TEA, DIPEA, TEMED and MeONa;

[0055] In certain embodiments, the inorganic base is selected from NaHCO 3 、Na 2 CO 3 , K 3 PO 4 One or more of .

[0056] In certain embodiments, the inorganic base is selected from NaHCO 3 .

[0057] In certain embodiments, the polypeptide sequence is composed of amino acid residues linked together;

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

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

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

[0061] In certain 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 certain embodiments, the polypeptide sequence is 1 to 20 amino acids in length.

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

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

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

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

[0067] In certain embodiments, the carboxyl protecting group is amino, tert-butyloxy, methoxy or ethoxy. In certain embodiments, the carboxyl protecting group is NH 2 .

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

[0069]

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

[0071]

[0072]

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

[0074]

[0075]

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

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

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

[0079] In certain 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 certain embodiments, the molar ratio of the compound represented by formula (I) to the copper acetate is 1 to 3:1.

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

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

[0083] In certain embodiments, the molar ratio of the compound represented by formula (I) to the base is 1:2-6, 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 certain embodiments, the molar ratio of the compound represented by formula (I) to the base is 1:3-5.

[0085] In certain 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

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

[0088] The term "amino acid" refers to a molecule containing an amino group and a carboxylic acid group and optionally containing one or more additional groups often referred to as side chains. The amino acids in the sequence of compounds of the present invention are derived from natural amino acids or related amino acid variants and / or derivatives. The abbreviations and codes of the natural amino acids adopt the general rules well known to those in the industry. Amino acids typically use standard single-letter codes (e.g., L = leucine) and α-methyl substituted residues of natural amino acids (e.g., α-methylleucine, or αMeL). Unless explicitly stated, all amino acid residues of the present invention are preferably in the L-configuration, and the D-configuration is also applicable, for example, dS represents D-type Ser.

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

[0090] Table 1

[0091] name Three-letter abbreviation Single letter abbreviation Alanine Ala A Aspartic acid Asp D Glutamate 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] When used in this article with respect to polypeptides, "amino acid" and "amino acid residue" have the same meaning, which means that when amino acids are connected by chemical bonds, part of their groups are lost due to participation in the formation of the connecting bonds, and the remaining amino acid part is the amino acid residue.

[0093] The term "polypeptide" refers to a sequence of two or more amino acids. A "peptide" may also include an extension of amino acids at the N-terminal and / or C-terminal positions and / or a truncation at the N-terminal and / or C-terminal positions. Typically, amino acid residues may be represented by their full names, their single-letter codes, and / or their three-letter codes. These three methods are completely equivalent.

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

[0095] The term "carboxyl protecting group" refers to a carboxyl substituent used to block or protect the functionality of the carboxyl group, and can be converted into a carboxyl protecting group by hydrolysis or deprotection reaction of the carboxyl protecting group. The carboxyl protecting group is preferably an alkyl group (e.g., methyl, ethyl, tert-butyl) or an aralkyl group (e.g., benzyl), and more preferably an amino group, a tert-butoxy group, a methoxy group, or an ethoxy group. In the present invention, a "protected carboxyl group" refers to a group formed after a carboxyl group is protected by a suitable carboxyl protecting group, and is preferably a methoxycarbonyl group, an ethoxycarbonyl group, a tert-butoxycarbonyl group, or a benzyloxycarbonyl group. The carboxyl protecting group can be removed by hydrolysis under the catalysis of an acid or a base, and occasionally by a thermal decomposition reaction, for example, the tert-butyl group can be removed under mild acidic conditions, and the benzyl group can be removed by hydrogenolysis. The reagent for removing the carboxyl protecting group is selected from TFA, H 2 O, LiOH, NaOH, KOH, MeOH, EtOH and combinations thereof, preferably TFA and H 2 The protected carboxyl group is deprotected to produce the corresponding free acid, and 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 the present invention, "amino protecting group" is equivalent to "amine protecting group" and includes all groups that can be used as conventional amino / amine protecting groups, such as aryl C 1-6 Alkyl, C 1-6 Alkoxy C 1-6 Alkyl, C 1-6 Alkoxycarbonyl, aryloxycarbonyl, C 1-6 The amino protecting group is preferably Ac (acetyl), Boc (tert-butyloxycarbonyl), Moz (p-methoxybenzyloxycarbonyl) or Fmoc (9-fluorenylmethyleneoxycarbonyl). The reagent for removing the amino protecting group is selected from TFA, H2O, LiOH, MeOH, EtOH and a combination thereof, preferably TFA and H 2 The deprotection agent used for removing the Fmoc protection is a solution of N,N-dimethylformamide (DMF) containing 20% ​​piperidine.

[0097] The term "hydroxy" refers to -OH.

[0098] The term "amino" refers to -NH 2 .

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

[0100] "Optional" or "optionally" means that the subsequently described event or circumstance may but need not occur, and the description includes instances where the event or circumstance occurs or does not occur. For example, "a heterocyclic group optionally substituted with an alkyl group" means that an alkyl group may but need not be present, and the description includes instances where the heterocyclic group is substituted with an alkyl group and instances where the heterocyclic group is not substituted with an alkyl group.

[0101] "Substituted" means that one or more hydrogen atoms, preferably 1 to 5, more preferably 1 to 3 hydrogen atoms in the group are replaced independently by a corresponding number of substituents. Those skilled in the art can determine possible or impossible substitutions (by experiment or theory) without undue effort. For example, an amino or hydroxyl group with free hydrogen may be unstable when combined with a carbon atom with an unsaturated (e.g., olefinic) bond.

[0102] In the present application, the "reaction yield" refers to the yield of the product calculated by detecting the product concentration in the reaction solution by LC-MS after the reaction is completed and before the product is purified.

[0103] The method of the present invention is described below by means of specific examples. It should be understood that these examples 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 examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in routine experiments.

[0104] In the following embodiments 1 H NMR spectra were measured using a Bruker instrument (400 MHz), and chemical shifts were expressed in ppm using tetramethylsilane as an internal standard (0.00 ppm). 1 HNMR notation: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broadened, dd = doublet of a doublet, dt = doublet of a triplet. Coupling constants, when given, are given in Hz.

[0105] The mass spectrum was obtained by LC / MS using ESI as the ionization method.

[0106] HPLC model: Agilent 1260, Thermo Fisher U3000; chromatographic column model: Waters xbrigeC18 (4.6*150mm, 3.5μm); mobile phase: A: ACN, B: Water (0.1% H 3 PO 4); 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°C.

[0107] TLC: Thin layer chromatography. The thin layer chromatography silica gel plate uses Yantai Huanghai HSGF254 or Qingdao GF254 silica gel plate. The specification of the silica gel plate used in thin layer chromatography (TLC) is 0.2mm-0.3mm, and the specification of the thin layer chromatography separation and purification product is 0.4mm-0.5mm.

[0108] Column chromatography generally uses Yantai Huanghai Silica Gel 200-300 mesh silica gel as the carrier.

[0109] In the following examples, unless otherwise specified, all temperatures are in degrees Celsius. Unless otherwise specified, various 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, commercial manufacturers include but are not limited to Sinopharm Group, J&K Technology Co., Ltd., TCI (Shanghai) Chemical Industry Development Co., Ltd., Shanghai Bid Pharmaceutical Technology Co., Ltd. and Shanghai Myrel 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, 20°C-30°C.

[0112] The reaction progress in the embodiment is monitored by thin layer chromatography (TLC), and the developing solvent used in the reaction, the system of eluent for column chromatography or the developing solvent system for thin layer chromatography used for purifying the compound includes: A: petroleum ether and ethyl acetate system; B: dichloromethane and methanol system; C: n-hexane: ethyl acetate; wherein the volume ratio of the solvent varies according to the polarity of the compound, and a small amount of acidic or alkaline reagent, such as acetic acid or triethylamine, can also be added for adjustment.

[0113] Example 1

[0114]

[0115] In an open glass bottle, a stirring bar, boronic acid derivative 1 (0.05mmol, 1 equivalent), copper acetate (0.025mmol, 0.5 equivalent), phenanthroline (0.025mmol, 0.5 equivalent) and 2mL of methanol were added. After stirring for 3 minutes, 4 equivalents of DIPEA were added and reacted at 40°C for 24 hours. LC-MS was used to monitor the reaction. After the reaction, the solvent was removed by a rotary evaporator, and the product was purified by preparative HPLC (water containing 1 / 1000 trifluoroacetic acid and acetonitrile as mobile phase).

[0116] The reaction yield of compound 1 in this example is 36%, and the mass spectrum data is: 36 H 51 N 9 O 8 S 770.3654[M+H] + ,1539.7235[2M+H] + , 770.3494, 1539.6936 were found. The mass spectrum of compound 1 prepared in this example is as follows Figure 1 shown.

[0117] Example 2

[0118]

[0119] Referring to the preparation method of Example 1, according to the amino acid sequence of compound 2 (Ac-Phe B -Ser-Ala-Pro-Leu-Ala-His-NH 2 ) was used to prepare compound 2, except that the starting materials were different. The reaction yield of the compound in this example was 49%, and the mass spectrometry data was: The molecular weight was calculated as: C 37 H 52 N 10 O 9 781.3991[M+H] + ,1561.7910[2M+H] + , 770.3858, 1561.7543 were found. The mass spectrum of compound 2 prepared in this example is as follows Figure 2 shown.

[0120] Example 3

[0121]

[0122] Referring to the preparation method of Example 1, according to the amino acid sequence of compound 3 (Ac-Phe B -Phe-Pro-Asp-Tyr-Ala-His-NH 2) prepared compound 3, the difference is that the raw materials are different, the reaction yield of the compound in this example is 32%, and the mass spectrum data is: The molecular weight is calculated as: C 47 H 54 N 10 O 11 935.4046[M+H] + , found 935.3856, the mass spectrum of compound 3 prepared in this example is as follows Figure 3 shown.

[0123] Example 4

[0124]

[0125] Referring to the preparation method of Example 1, according to the amino acid sequence of compound 4 (Ac-Phe B -Leu-Asp-Pro-Ala-Ser-Ala-His-NH 2 ) prepared compound 4, the difference is that the raw materials are different, the reaction yield of the compound in this example is 29%, and the mass spectrum data is: The molecular weight is calculated as: C 41 H 57 N 11 O 12 896.4261[M+H] + ,1791.8449[2M+H] + , 896.4074, 1791.8069 were found. The mass spectrum of compound 4 prepared in this example is as follows Figure 4 shown.

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

Claims

1. A method for preparing a compound represented by formula (II), characterized in that: The compound represented by formula (I) is reacted in the presence of copper acetate and phenanthroline to obtain the compound represented by formula (II). Wherein, R1 is hydrogen or an amino protecting group; R2 is a polypeptide sequence; R3 is a hydroxyl or carboxyl protecting group.

2. The method according to claim 1, characterized in that 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; Preferably, the solvent is selected from one or more of MeOH, MeCN, and EtOH; More preferably, the solvent is selected from MeOH.

3. The method according to claim 1, characterized in that The method is carried out in the presence of a base, wherein the base is selected from an organic base or an inorganic base; Preferably, the organic base is selected from one or more of TEA, DIPEA, DABCO, TEMED, MeONa, t-BuOK, 2,6-Lutidine, and Py; more preferably, one or more of TEA, DIPEA, TEMED, and MeONa; Preferably, the inorganic base is selected from one or more of NaHCO3, Na2CO3, K3PO4; more preferably, NaHCO3.

4. The method according to claim 1, characterized in that: The polypeptide sequence is formed by connecting amino acid residues; Preferably, the amino acid is selected from one or more of substituted or unsubstituted Tyr, Ala, Val, Leu, Ile, Met, Phe, Pro, Lys, Trp, Asp, Gly, Ser, Glu, Thr, His; preferably one or more of Tyr, Asp, Ala, Ser, His, Leu, Met, Phe, Pro; The substitution is substituted with at least one substituent selected from amino or Boc.

5. The method according to claim 1, characterized in that The length of the polypeptide sequence is 1 to 39 amino acids, preferably 1 to 20 amino acids, and more preferably 1 to 10 amino acids; Preferably, the amino protecting group is Ac, Boc, Moz or Fmoc; Preferably, the carboxyl protecting group is amino, tert-butoxy, methoxy or ethoxy.

6. The method according to claim 1, characterized in that The compound represented by formula (I) is a compound represented by formula (I-1):

7. The method according to claim 6, characterized in that The compound represented by formula (I-1) is selected from any one of the following:

8. The method according to claim 1, characterized in that The molar ratio of the copper acetate to the phenanthroline is 1:0.5-3, preferably 1:0.5-2.

9. The method according to claim 1, characterized in that: The molar ratio of the compound represented by formula (I) to the copper acetate is 1 to 5:1, preferably 1 to 3:

1.

10. The method according to claim 1, characterized in that The reaction temperature is 35 to 45° C., and the reaction time is 15 to 35 hours.

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