Method for producing peptide compounds using novel silyl tags

Abstract

The present invention provides a method for preventing a decrease in solubility in organic solvents during peptide chain elongation by a peptide bond reaction and improving the reactivity of the peptide chain and operability during the purification process. The method obtains a polypeptide compound by subjecting a carboxyl group on the right side of the formula of an amino acid or peptide compound of formula (R1) to an amide-forming reaction with an amino group on the left side of the formula of an amino acid ester or peptide ester compound of formula (R2) whose terminal carboxyl group is protected by a silicon-containing hydrophobic substituent TAG(Si). JPEG0007625769000056.jpg124150 (wherein the definitions of each symbol are as described in the claims.)

Description

[Technical field]

[0001] The present invention relates to a novel method for producing a peptide compound using a novel silyl tag. [Background technology]

[0002] Traditionally, amide compounds, such as peptides, have been used in a wide range of fields, including pharmaceuticals, cosmetics, and functional foods, and the development of methods for synthesizing them has been vigorously pursued as an important research topic in synthetic chemistry (Non-Patent Documents 1-3). However, for amidation, which is the most important step in peptide synthesis, there are almost no truly effective catalysts or reactants other than carboxylic acid activators. Therefore, a reaction mode that produces a large amount of by-products must be used, and peptide synthesis, which involves repeated multi-step reactions, is extremely inefficient from the standpoint of atom economy (atomic yield), and the by-products are produced in huge quantities, and there are few effective purification methods. As a result, the cost of disposing of and purifying the by-products accounts for most of the necessary expenses in peptide synthesis, which is one of the biggest obstacles to the development of this field.

[0003] In peptide synthesis using amino acids or their derivatives as raw materials, highly stereoselective amidation is required. An example of highly stereoselective amidation is an enzyme reaction in vivo. For example, peptides are synthesized in vivo with extremely high stereoselectivity by skillfully utilizing enzymes and hydrogen bonds. However, enzyme reactions are not suitable for mass production, and applying them to synthetic chemistry requires huge financial and time costs.

[0004] In synthetic chemistry, amidation using a catalyst has also been investigated. However, in conventional methods, amide bonds are mainly formed by activating carboxylic acids, which leads to rapid racemization, making it difficult to synthesize amide compounds efficiently and with high stereoselectivity.

[0005] Furthermore, in conventional methods, it is extremely difficult to chemically ligate a peptide formed by linking a plurality of amino acids or derivatives thereof with an amide bond, or to ligate two or more peptides with an amide bond. As amidation methods for ligating such peptides, there are known a method in which an amino acid having a sulfur atom is used to perform ligation utilizing the high reactivity of the sulfur atom (Non-Patent Document 4), and a method in which a hydroxylamine of an amino acid is synthesized and ligation is performed utilizing the high reactivity of the hydroxylamine (Non-Patent Document 5). However, the former method requires the difficulty of synthesizing an amino acid having a sulfur atom, and the latter method requires the separate synthesis of hydroxylamine over several steps, so that both methods are time-consuming, costly, and inefficient.

[0006] The present inventors have developed technologies for synthesizing amide compounds with high chemoselectivity, such as a method of amidating a carboxylic acid / ester compound having a hydroxy group at the β-position in the presence of a specific metal catalyst (Patent Document 1), a method of using a hydroxyamino / imino compound as an amino acid precursor, amidating this in the presence of a specific metal catalyst, and then reducing it in the presence of a specific metal catalyst (Patent Document 2), and a method of amidating a carboxylic acid / ester compound in the presence of a specific metal catalyst (Patent Document 3). Furthermore, they have also developed a technique for synthesizing peptides consisting of various amino acid residues with high efficiency and high selectivity by amidating the carboxyl group of an N-terminal protected amino acid / peptide with the amino group of a C-terminal protected amino acid / peptide in the presence of a specific silylating agent (and a Lewis acid catalyst, which is optionally used in combination), followed by deprotection (Patent Document 4); a technique for synthesizing peptides consisting of various amino acid residues with high efficiency and high selectivity by amidating the carboxyl group of an N-terminal protected or unprotected amino acid / peptide with the amino group of a C-terminal protected or unprotected amino acid / peptide in the presence of a specific silylating agent, followed by deprotection (Patent Documents 5 and 6); a technique for performing an amidation reaction using a Brønsted acid as a catalyst (Patent Document 7); a novel silane-containing fused ring dipeptide compound and a novel method for synthesizing peptides using the compound (Patent Document 8); and a novel method for synthesizing peptides by site-selective CN bond cleavage of lactam (Non-Patent Document 8).

[0007] Incidentally, most peptide drugs currently on the market are oligopeptides with five or more amino acid residues. However, as the peptide chain is extended by the peptide bond reaction, the polarity of the peptide increases significantly, and the solubility in the organic solvent used as the reaction solvent decreases significantly. This not only significantly reduces the reactivity of the peptide chain, but also poses a major disadvantage in terms of operability in the purification process. Therefore, in the synthesis of oligopeptides, a strategy that can ensure solubility in organic solvents during the peptide chain extension reaction is essential.

[0008] As a technique for ensuring the solubility and reactivity of a peptide chain in an organic solvent, a technique for linking an alkoxybenzyl ester (TAGa) group, in which a long-chain alkyl is linked to an aromatic ring, to a peptide chain as a protecting group has been reported (Non-Patent Document 6). However, this technique has a limited effect of improving the solubility of a peptide chain in an organic solvent. In addition, in the study by the present inventors, insoluble solids were observed during the reaction process with this technique, suggesting the possibility that deprotection of the ester may occur during the reaction process. [ka]

[0009] Another technique has been reported in which a silyl ester group is used as a protecting group to link to a peptide chain (Non-Patent Document 7). However, this technique uses a highly reactive silyl ester group as a protecting group, which limits the reaction conditions that can be applied to the peptide bond reaction. In addition, this technique may also cause deprotection of the ester during the reaction, and deprotection has been frequently confirmed and reported in this document. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2017 / 204144 [Patent Document 2] International Publication No. 2018 / 199146 [Patent Document 3] International Publication No. 2018 / 199147 [Patent Document 4] International Publication No. 2019 / 208731 [Patent Document 5] International Publication No. 2021 / 085635 [Patent Document 6] International Publication No. 2021 / 085636 [Patent Document 7] International Publication No. 2021 / 149814 [Patent Document 8] International Publication No. 2022 / 190486 [Non-patent literature]

[0011] [Non-Patent Document 1] Chem. Rev., 2011, Vol.111, p.6557-6602 [Non-Patent Document 2] Org. Process Res. Dev., 2016, Vol.20, No.2, p.140-177 [Non-Patent Document 3] Chem. Rev., 2016, Vol.116, p.12029-12122 [Non-Patent Document 4] Science, 1992, Vol.256, p.221-225 [Non-Patent Document 5] Angew. Chem. Int. Ed., 2006, Vol.45, p.1248-1252 [Non-Patent Document 6] Org. Process Res. Dev. 2019, Vol.23, p.2576-2581 [Non-Patent Document 7] Org. Process Res. Dev. 2021, Vol.25, p.2029-2038 [Non-Patent Document 8] Chem. Sci., (2022), Vol.13, pp.6309-6315 Summary of the Invention [Problem to be solved by the invention]

[0012] In view of the above, there has been a demand for a method for preventing a decrease in solubility in organic solvents during peptide chain elongation by a peptide bond reaction, improving the reactivity of peptide chains and operability in the purification process, and obtaining a desired peptide with high efficiency. [Means for solving the problem]

[0013] As a result of intensive research, the present inventors have found that by subjecting an amino acid or peptide in which the terminal carboxyl group and / or terminal amino group is protected by a silicon-containing hydrophobic substituent having a specific structure to peptide chain elongation by a peptide bond reaction, it is possible to prevent a decrease in the solubility of the peptide chain in an organic solvent, and to maintain or improve the reactivity of the peptide chain and the operability in the purification process. Furthermore, it has been found that such a silicon-containing hydrophobic substituent is stable and not decomposed under the conditions for deprotection of the amino group-protecting group, and can be efficiently removed by hydrolysis after completion of peptide elongation, making it possible to obtain a desired peptide with high efficiency, thereby arriving at the present invention.

[0014] That is, the gist of the present invention is as follows. [Item 1] A method for producing a polypeptide compound, comprising: subjecting a carboxyl group on the right side of an amino acid or peptide compound represented by the following formula (R1) to an amide-forming reaction with an amino group on the left side of an amino acid ester or peptide ester compound represented by the following formula (R2), thereby obtaining a peptide compound represented by the following formula (P1): [ka] In formula (R1), T a represents a hydrogen atom or a monovalent substituent, R 11 and R 12 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, or a thiol group, or an amino group, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent heterocyclic group, each of which may have one or more substituents; R 13represents a hydrogen atom, a carboxyl group, a hydroxyl group, or a monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group which may have one or more substituents, in which case the monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group may be bonded to a nitrogen atom via a linking group, Or, R 11 and R 13 and are bonded to each other to form R 11 The carbon atom to which R is bonded 13 may form a heterocycle together with the nitrogen atom to which it is bonded which may have one or more substituents, A 11 and A 12 each independently represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have one or more substituents, p11 and p12 each independently represent 0 or 1; n 1 is an integer of 1 or more and represents the number of structural units represented by the structure in [ ]. 1 When is 2 or more, the multiple constitutional units represented by the structure in [ ] may be the same or different. [ka] In formula (R2), T b represents a hydrogen atom or a monovalent substituent, R 21 and R 22 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, or a thiol group, or an amino group, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent heterocyclic group, each of which may have one or more substituents; R 23 represents a hydrogen atom, a carboxyl group, a hydroxyl group, or a monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group which may have one or more substituents, in which case the monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group may be bonded to a nitrogen atom via a linking group, Or, R 21 and R 23 and are bonded to each other to form R 21 The carbon atom to which R is bonded 23 may form a heterocycle together with the nitrogen atom to which it is bonded which may have one or more substituents, A 21 and A 22 each independently represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have one or more substituents, p21 and p22 each independently represent 0 or 1; n 2 is an integer of 1 or more and represents the number of structural units represented by the structure in [ ]. 2 When is 2 or more, the multiple constitutional units represented by the structure in [ ] may be the same or different. however, (i)T a is a group represented by -OC(=O)-TAG(Si), and / or (ii) T b is a group represented by -TAG(Si). Here, -TAG(Si) is a group having the structure shown below. [ka] In formula (T), R x represents a divalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group, which may have one or more substituents; R z1 ~R z9 each independently represents a monovalent aliphatic hydrocarbon group, an aromatic hydrocarbon group, a silicon-containing hydrocarbon group, or a heterocyclic group, which may have one or more substituents, provided that R z1 ~R z9 At least one of these is an aliphatic hydrocarbon group having 7 or more carbon atoms which may have one or more substituents. [ka] In formula (P1), Ta , R 11 , R 12 , R 13 , A 11 , A 12 , p11, p12, and n 1 represents the same group as defined in the above formula (R1), R 21 , R 22 , R 23 , A 21 , A 22 , p21, p22, n 2 , and T b represents the same group as defined in the above formula (R2). [Term 2] In formula (T), R z1 ~R z9 Item 3. The method according to Item 1, wherein at least three of the above are aliphatic hydrocarbon groups having 7 or more carbon atoms which may have one or more substituents. [Term 3] In formula (T), R x Item 3. The method according to item 1 or 2, wherein the divalent aliphatic hydrocarbon has two or more carbon atoms. [Item 4] The method according to any one of Items 1 to 3, wherein the reaction is carried out in an organic solvent. [Item 5] The method according to any one of Items 1 to 4, wherein the reaction is carried out in the presence of a Lewis acid catalyst. [Item 6] The method according to Item 5, wherein the Lewis acid catalyst is a metal compound containing one or more metals selected from the group consisting of aluminum, titanium, zirconium, hafnium, tantalum, and niobium. [Item 7] The method according to any one of Items 1 to 6, wherein the reaction is carried out in the presence of a phosphorus compound. [Item 8] The method according to Item 7, wherein the phosphorus compound is a phosphine compound or a phosphate compound. [Item 9] The method according to any one of Items 1 to 8, wherein the reaction is carried out in the presence of a silane compound. [Item 10] T in the above formula (R1) aItem 10. The method according to any one of Items 1 to 9, further comprising a step of removing the -OC(=O)-TAG(Si) group of the peptide compound of formula (P1) after synthesis thereof to deprotect the terminal amino group of the peptide compound. [Term 11] T in the above formula (R2) b 11. The method according to any one of items 1 to 10, further comprising a step of removing the -TAG(Si) group of the peptide compound of formula (P1) after synthesis thereof to deprotect the terminal carboxyl group of the peptide compound. [Item 12] The method according to any one of items 1 to 11, wherein the reaction is a batch reaction or a flow reaction. [Item 13] An amino acid or peptide compound represented by the following formula (R1'): [ka] In formula (R1'), R 11 , R 12 , R 13 , A 11 , A 12 , p11, p12, n 1 The definitions of each of the groups having the same symbols as described in item 1 are the same as those of the groups having the same symbols as described in item 1. [Item 14] An amino acid ester or peptide ester compound represented by the following formula (R2'): [ka] In formula (R2'), R 21 , R 22 , R 23 , A 21 , A 22 , p21, p22, n 2 The definitions of each of the groups having the same symbols as described in item 1 are the same as those of the groups having the same symbols as described in item 1. [Item 15] A peptide compound represented by the following formula (P1'): [ka] In formula (P1'), R11 , R 12 , R 13 , R 21 , R 22 , R 23 , A 11 , A 12 , A 21 , A 22 , p21, p22, p11, p12, n 1 , n 2 , T a , and T b has the same definition as the group having the same symbol described in item 1. however, (i)T a is a group represented by -OC(=O)-TAG(Si), and / or (ii) T b is a group represented by -TAG(Si). The definition of TAG(Si) is the same as the definition of the group having the same symbol described in item 1. [Item 16] A compound represented by the following formula (C0). [ka] In formula (C0), the definition of TAG(Si) is the same as the definition of the group having the same symbol described in item 1. be. [Item 17] A compound represented by the following formula (C1). [ka] In formula (C1), the definition of TAG(Si) is the same as the definition of the group having the same symbol described in item 1. R C1 is any monovalent group. [Item 18] A compound represented by the following formula (C2). [ka] In formula (C2), TAG(Si) is defined as the same as the group having the same symbol described in item 1. R C21 and R C22 are each independently any monovalent group. [Term 19] In formula (T), Rz1 ~R z9 19. The compound according to any one of items 16 to 18, wherein at least three of the above are aliphatic hydrocarbon groups having 7 or more carbon atoms which may have one or more substituents. [Term 20] In formula (T), R x 20. The compound according to any one of items 16 to 19, wherein is a divalent aliphatic hydrocarbon having 2 or more carbon atoms. Effect of the Invention

[0015] According to the method of the present invention, by subjecting an amino acid or peptide whose terminal carboxyl group and / or terminal amino group are protected by a silicon-containing hydrophobic substituent having a specific structure to peptide chain elongation by a peptide bond reaction, it is possible to prevent a decrease in the solubility of the peptide chain in an organic solvent, thereby improving the reactivity of the peptide chain and the operability in the purification process. Moreover, such a silicon-containing hydrophobic substituent exists stably without being decomposed under the conditions for deprotection of the amino group-protecting group, and can be efficiently removed by hydrolysis after completion of peptide elongation, making it possible to obtain the desired peptide with high efficiency. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention will be described in detail below with reference to specific embodiments. However, the present invention is not limited to the following embodiments, and can be embodied in any form without departing from the spirit of the present invention.

[0017] All patent publications, published patent applications, and non-patent publications cited in this disclosure are hereby incorporated by reference in their entirety into this disclosure for all purposes.

[0018] [I. Definitions of Terms] In the present disclosure, "amino acid" refers to a compound having a carboxyl group and an amino group. Unless otherwise specified, the type of amino acid is not particularly limited. For example, from the viewpoint of optical isomerism, it may be D-form, L-form, or racemic. In addition, from the viewpoint of the relative position of the carboxyl group and the amino group, it may be any of α-amino acid, β-amino acid, γ-amino acid, δ-amino acid, ω-amino acid, etc. Examples of amino acids include, but are not limited to, natural amino acids that constitute proteins, and specific examples include valine, leucine, isoleucine, alanine, arginine, glutamine, lysine, aspartic acid, glutamic acid, proline, cysteine, threonine, methionine, histidine, phenylalanine, tyrosine, tryptophan, asparagine, glycine, serine, etc.

[0019] In the present disclosure, "peptide" refers to a compound in which multiple amino acids are linked via peptide bonds. Unless otherwise specified, the multiple amino acid units constituting a peptide may be the same type of amino acid unit, or may be two or more different types of amino acid units. The number of amino acids constituting a peptide is not particularly limited as long as it is two or more. Examples include 2 (also called "dipeptide"), 3 (also called "tripeptide"), 4 (also called "tetrapeptide"), 5 (also called "pentapeptide"), 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 100, or more. In addition, the term "polypeptide" may refer to a peptide that is tripeptide or more.

[0020] In the present disclosure, the term "amino group" refers to a functional group represented by the formula -NH2, -NRH, or -NRR' (wherein R and R' each represent a substituent) obtained by removing hydrogen from ammonia, a primary amine, or a secondary amine, respectively.

[0021] In the present disclosure, unless otherwise specified, the hydrocarbon group may be aliphatic or aromatic. The aliphatic hydrocarbon group may be linear or cyclic. The linear hydrocarbon group may be linear or branched. The cyclic hydrocarbon group may be monocyclic, bridged, or spirocyclic. The hydrocarbon group may be saturated or unsaturated, in other words, may contain one or more carbon-carbon double bonds and / or triple bonds. That is, the hydrocarbon group is a concept including alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, cycloalkenyl groups, cycloalkynyl groups, aryl groups, arylalkyl groups, alkylaryl groups, and the like. In addition, unless otherwise specified, one or more hydrogen atoms of the hydrocarbon group may be substituted with any substituent, and one or more carbon atoms of the hydrocarbon group may be substituted with any heteroatom depending on the valence.

[0022] In the present disclosure, the term "hydrocarbonoxy group" refers to a group in which a hydrocarbon group as defined above is linked to one bond of an oxy group (-O-). In other words, the term "hydrocarbonoxy group" encompasses alkyloxy groups, alkenyloxy groups, alkynyloxy groups, cycloalkyloxy groups, cycloalkenyloxy groups, cycloalkynyloxy groups, aryloxy groups, and the like.

[0023] In the present disclosure, the term "hydrocarbon carbonyl group" refers to a group in which a hydrocarbon group as defined above is linked to one bond of a carbonyl group (-C(=O)-). In other words, the term "hydrocarbon carbonyl group" encompasses alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, cycloalkylcarbonyl groups, cycloalkenylcarbonyl groups, cycloalkynylcarbonyl groups, arylcarbonyl groups, and the like.

[0024] In the present disclosure, the term "hydrocarbon sulfonyl group" refers to a group in which a hydrocarbon group as defined above is linked to one bond of a sulfonyl group (-S(=O)-). In other words, the term "hydrocarbon sulfonyl group" encompasses alkylsulfonyl groups, alkenylsulfonyl groups, alkynylsulfonyl groups, cycloalkylsulfonyl groups, cycloalkenylsulfonyl groups, cycloalkynylsulfonyl groups, arylsulfonyl groups, and the like.

[0025] In the present disclosure, a "heterocyclic group" may be saturated or unsaturated, in other words, it may contain one or more carbon-carbon double bonds and / or triple bonds. In addition, a heterocyclic group may be a monocyclic, bridged, or spirocyclic group. In addition, the heteroatoms contained in the heterocyclic ring of a heterocyclic group are not limited, and examples thereof include nitrogen, oxygen, sulfur, phosphorus, silicon, etc.

[0026] In the present disclosure, the term "heterocyclic oxy group" refers to a group in which a heterocyclic group as defined above is linked to one bond of an oxy group (-O-).

[0027] In the present disclosure, the term "heterocyclic carbonyl group" refers to a group in which a heterocyclic group as defined above is linked to one bond of a carbonyl group (-C(=O)-).

[0028] In the present disclosure, the term "heterocyclic sulfonyl group" refers to a group in which a heterocyclic group as defined above is linked to one bond of a sulfonyl group (-S(=O)2-).

[0029] In the present disclosure, a "metaloxy group" (which may have one or more substituents) is a group represented by the formula (R n In the formula, M represents an arbitrary metal element, R represents an arbitrary substituent, and n represents an integer of 0 to 8 that can be taken depending on the coordination number of the metal element M.

[0030] In the present disclosure, the term "substituent" refers to any substituent that is not particularly limited as long as the amidation step in the production method of the present invention proceeds, unless otherwise specified. Examples of the substituent include, but are not limited to, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a thiol group, a sulfonic acid group, an amino group, an amido group, an imino group, an imido group, a hydrocarbon group, a heterocyclic group, a hydrocarbonoxy group, a hydrocarboncarbonyl group (acyl group), a hydrocarbonoxycarbonyl group, a hydrocarboncarbonyloxy group, a hydrocarbon-substituted amino group, a hydrocarbon-substituted aminocarbonyl group, a hydrocarboncarbonyl-substituted amino group, a hydrocarbon-substituted thiol group, a hydrocarbonsulfonyl group, a hydrocarbonoxysulfonyl group, a hydrocarbonsulfonyloxy group, a heterocyclicoxy group, a heterocycliccarbonyl group, a heterocyclicoxycarbonyl group, a heterocycliccarbonyloxy group, a heterocyclicamino group, a heterocyclicaminocarbonyl group, a heterocycliccarbonyl-substituted amino group, a heterocyclic-substituted thiol group, a heterocyclicsulfonyl group, a heterocyclicoxysulfonyl group, a heterocyclicsulfonyloxy group, and the like. In addition, as long as the valence and physicochemical properties of these functional groups allow, functional groups further substituted with these functional groups are also included in the "substituent" in the present disclosure. When a functional group has a substituent, the number of the substituents is not particularly limited as long as the valence and physicochemical properties allow. In addition, when multiple substituents are present, these substituents may be the same or different from each other.

[0031] The main abbreviations used in this disclosure are shown in Tables 1-1 and 1-2 below. [Table 1-1] [Table 1-2]

[0032] In this disclosure, amino acids and their residues may be represented by three-letter abbreviations well known to those skilled in the art. The three-letter abbreviations of the main amino acids used in this disclosure are shown in the following table. [Table 2]

[0033] In this disclosure, β-homo amino acids and residues thereof may be referred to by adding "Ho" before the three letter abbreviation of the corresponding α-amino acid.

[0034] In the present disclosure, the term "protecting group" refers to a functional group that can be introduced onto the nitrogen atom of an amino group or an amide group under specific reaction conditions and can be removed under specific reaction conditions. Representative protecting groups are described in detail in several textbooks, for example, Peter GM Wuts, Green's Protective Groups in Organic Synthesis, 5th Edition, Wiley, 2014, etc.

[0035] In the present disclosure, the term "alkyl-type protecting group" refers to a hydrocarbon group that can be easily attached to and removed from the nitrogen atom of an amino group or an amide group. Examples include an unsubstituted or substituted benzyl group, an unsubstituted or substituted allyl group, and the like.

[0036] In the present disclosure, the term "electron-withdrawing protecting group" refers to a protecting group that acts as a protecting group for an amino group or an amide group, by drawing electrons on a nitrogen atom toward the protecting group. Examples of the protecting group include an acyl group, an alkyloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group.

[0037] [II. Method for producing peptide compounds] ·overview One aspect of the present invention relates to a method for producing a polypeptide compound, which comprises subjecting a carboxyl group on the right side of an amino acid or peptide compound of formula (R1) to an amide-forming reaction with an amino group on the left side of an amino acid ester or peptide ester compound of formula (R2) to obtain a peptide compound of formula (P1) (hereinafter referred to as the "method for producing the peptide compound of the present invention" or simply the "production method of the present invention" as appropriate). [ka] [ka] [ka]

[0038] ·Substrate compound In the above general formulas (R1) and (R2), the definitions of each symbol are as follows.

[0039] R 11 , R 12 , R 21 , and R 22 Each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, or a thiol group, or a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents. When these groups have a substituent, the type of the substituent is as described above. Specific examples of the number of substituents are, for example, 5, 4, 3, 2, 1, or 0.

[0040] Also, R 11 , R 12 , R 21 , and / or R 22 is a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents, a linking group may be present between the hydrocarbon group or heterocyclic group and the carbon atom to which it is bonded. Such linking groups are not limited, but may be each independently selected from the structures shown below (note that in the chemical formulas below, each A independently represents a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents. When there are two A's in the same group, they may be the same or different).

[0041] [ka]

[0042] The number of carbon atoms in the hydrocarbon group (including the substituent if any) is not particularly limited, but the upper limit is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of hydrocarbon group, but is 1 or more for an alkyl group, 2 or more for an alkenyl group or alkynyl group, and 3 or more for a cycloalkyl group, for example, 4 or more or 5 or more. Specific examples of the number of atoms are, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0043] The total number of carbon atoms and heteroatoms (including substituents, if any) in the heterocyclic group is not particularly limited, but the upper limit is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of heterocyclic structure, but is usually 3 or more, for example, 4 or more, or 5 or more. Specific examples of the number of atoms are, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0044] Among them, R 11 , R 12 , R 21 , and R 22 are preferably each independently a hydrogen atom, a hydroxyl group, a thiol group, a carboxyl group, a nitro group, a cyano group, or a halogen atom, or an amino group, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, a heterocyclic group, or a heterocyclic oxy group, which may have one or more substituents.

[0045] R 11 , R 12 , R 21 , and R 22 Specific examples include, but are not limited to, the following:

[0046] Hydrogen atoms, hydroxyl groups, thiol groups, carboxyl groups, nitro groups, cyano groups; Halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; Alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, decyl, and nonyl; Alkenyl groups such as ethenyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl; Alkynyl groups, such as propargyl groups; Cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclooctyl, and spirooctyl groups; Alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, sec-butoxy, and tert-butoxy; Aryl groups such as phenyl, benzyl, tolyl, naphthyl, and anthracenyl; Aryloxy groups such as phenyloxy, benzyloxy, and naphthyloxy; Acyl groups such as acetyl, propionyl, benzoyl, p-methoxybenzoyl, and cinnamoyl; Unsubstituted amino groups and substituted amino groups such as dimethylamino groups, benzylamino groups, and triphenylmethylamino groups; Furanyl group, thiophenyl group, pyranyl group, pyrrolinyl group, pyrrolyl group, 2,3-dihydro-1H-pyrrolyl group, piperidinyl group, piperazinyl group, homopiperazinyl group, morpholino group, thiomorpholino group, 1,2,4,6-tetrahydropyridyl group, hexahydropyrimidyl group, hexahydropyridazyl group, 1,2,4,6-tetrahydropyridyl group, 1,2,4,6-tetrahydropyridazyl group, 3,4-dihydropyridyl group, imidazolyl group, 4,5-dihydro-1H-imidazolyl group heterocyclic groups such as an alkyl group, a 2,3-dihydro-1H-imidazolyl group, a pyrazolyl group, a 4,5-dihydro-1H-pyrazolyl group, a 2,3-dihydro-1H-pyrazolyl group, an oxazolyl group, a 4,5-dihydro-1,3-oxazolyl group, a 2,3-dihydro-1,3-oxazolyl group, a 2,5-dihydro-1,3-oxazolyl group, a thiazolyl group, a 4,5-dihydro-1,3-thiazolyl group, a 2,3-dihydro-1,3-thiazolyl group, a 2,5-dihydro-1,3-thiazolyl group, and a carbazolyl group; Heterocyclic oxy groups such as a furanyloxy group, a pyrrolyloxy group, an indolyloxy group, a quinolyloxy group, etc.

[0047] Among the above groups, the group having a carboxyl group may or may not have a protecting group. Although it depends on the reactivity between the compound (R1) and the compound (R2) used in the reaction, when the group having a carboxyl group among the above groups has a protecting group, the reaction selectivity with the carboxylate group on the right side in the formula of the compound (R2) is usually improved compared to the reaction selectivity with the carboxyl groups present in other substituents.

[0048] R 13 and R 23 Each independently represents a hydrogen atom, a carboxyl group, or a hydroxyl group, or a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents. When the group has a substituent, the type of the substituent is as described above. Specific examples of the number of the substituents are, for example, 5, 4, 3, 2, 1, or 0.

[0049] Also, R 13 and / or R23 is a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents, a linking group may be present between the hydrocarbon group or heterocyclic group and the nitrogen atom to which it is bonded. Such linking groups are not limited, but may be each independently selected from the structures shown below (note that in the chemical formulas below, each A independently represents a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents. When there are two A's in the same group, they may be the same or different).

[0050] [ka]

[0051] The upper limit of the number of carbon atoms in the hydrocarbon group (including the substituent if any) is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of hydrocarbon group, but is 1 or more for an alkyl group, 2 or more for an alkenyl group or alkynyl group, and 3 or more for a cycloalkyl group, for example, 4 or more or 5 or more. Specific examples of the number of atoms are, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0052] The upper limit of the total number of carbon atoms and heteroatoms (including substituents, if any) in the heterocyclic group is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of heterocyclic structure, but is usually 3 or more, for example, 4 or more, or 5 or more. Specific examples of the number of atoms are, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0053] Among them, R 13 and R 23are preferably each independently a hydrogen atom, a hydroxyl group, or a carboxyl group, or an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, a heterocyclic group, or a heterocyclic oxy group, each of which may have one or more substituents.

[0054] R 13 and R 23 Specific examples include, but are not limited to, the following:

[0055] Hydrogen atoms, hydroxyl groups, carboxyl groups; Alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, decyl, and nonyl; Alkenyl groups such as ethenyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl; Alkynyl groups, such as propargyl groups; Cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclooctyl, and spirooctyl groups; Aryl groups such as phenyl, benzyl, tolyl, naphthyl, and anthracenyl; Furanyl, thiophenyl, pyranyl, pyrrolinyl, pyrrolyl, 2,3-dihydro-1H-pyrrolyl, piperidinyl, piperazinyl, homopiperazinyl, morpholino, thiomorpholino, 1,2,4,6-tetrahydropyridyl, hexahydropyrimidyl, hexahydropyridazyl, 1,2,4,6-tetrahydropyridyl, 1,2,4,6-tetrahydropyridazyl, 3,4-dihydropyridyl, imidazolyl, 4,5-dihydro-1H-imidazolyl heterocyclic groups such as a 2,3-dihydro-1H-imidazolyl group, a pyrazolyl group, a 4,5-dihydro-1H-pyrazolyl group, a 2,3-dihydro-1H-pyrazolyl group, an oxazolyl group, a 4,5-dihydro-1,3-oxazolyl group, a 2,3-dihydro-1,3-oxazolyl group, a 2,5-dihydro-1,3-oxazolyl group, a thiazolyl group, a 4,5-dihydro-1,3-thiazolyl group, a 2,3-dihydro-1,3-thiazolyl group, a 2,5-dihydro-1,3-thiazolyl group, a carbazolyl group, and the like;

[0056] In addition, R 11 and R 13 and are bonded to each other to form R 11 The carbon atom to which R is bonded 13 may form a heterocycle optionally having one or more substituents together with the nitrogen atom to which R is bonded, 21 and R 23 and are bonded to each other to form R 21 The carbon atom to which R is bonded 23 may form a heterocycle which may have one or more substituents together with the nitrogen atom to which it is bonded. When it has a substituent, the type of the substituent is as described above. Specific examples of the number of the substituents are, for example, 5, 4, 3, 2, 1, or 0.

[0057] The upper limit of the total number of carbon atoms and heteroatoms (including substituents, if any) in the heterocyclic group is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of heterocyclic structure, but is usually 3 or more, for example, 4 or more, or 5 or more. Specific examples of the number of atoms are, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0058] Specific examples of such heterocycles include, but are not limited to, a pyrrolinyl group, a pyrrolyl group, a 2,3-dihydro-1H-pyrrolyl group, a piperidinyl group, a piperazinyl group, a homopiperazinyl group, a morpholino group, a thiomorpholino group, a 1,2,4,6-tetrahydropyridyl group, a hexahydropyrimidyl group, a hexahydropyridazyl group, a 1,2,4,6-tetrahydropyridyl group, a 1,2,4,6-tetrahydropyridazyl group, a 3,4-dihydropyridyl group, an imidazolyl group, a 4,5-dihydropyridyl group, a 5,6-dihydropyridyl group, a 6,7-dihydropyridyl group, a 7,8-dihydropyridyl group, a 8,9-dihydropyridyl group, a 9,10-dihydropyridyl group, a 11,12-dihydropyridyl group, a 12,13-dihydropyridyl group, a 13,14-dihydropyridyl group, a 14,15-dihydropyridyl group, a 15,16-dihydropyridyl group, a 17,18-dihydropyridyl group, a 19,19-dihydropyridyl group, a 20,11-dihydropyridyl group, a 21,12-dihydropyridyl group, a 22,13-dihydropyridyl group, a 23,14-dihydropyridyl group, a 24,15-dihydropyridyl group, a 25,16-dihydropyridyl group, a 26,17-dihydropyridyl group, a 27,18-dihydropyridyl group, a 28,19-dihydropyridyl group, a 29,11-dihydropy -1H-imidazolyl group, 2,3-dihydro-1H-imidazolyl group, pyrazolyl group, 4,5-dihydro-1H-pyrazolyl group, 2,3-dihydro-1H-pyrazolyl group, oxazolyl group, 4,5-dihydro-1,3-oxazolyl group, 2,3-dihydro-1,3-oxazolyl group, 2,5-dihydro-1,3-oxazolyl group, thiazolyl group, 4,5-dihydro-1,3-thiazolyl group, 2,3-dihydro-1,3-thiazolyl group, and 2,5-dihydro-1,3-thiazolyl group.

[0059] A 11 , A 12 , A 21 , and A 22 each independently represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have one or more substituents. Specific examples include, but are not limited to, a methylene group, an ethylene group, a propylene group, an isopropylene group, and the like, as well as groups in which these groups are substituted with one or more of the above-mentioned substituents. Specific examples of the number of substituents are, for example, 3, 2, 1, or 0.

[0060] p11, p12, p21, and p22 each independently represent 0 or 1.

[0061] n 1 is an integer of 1 or more, which represents the number of amino acid units in the brackets [ ] of general formula (R1). 1 When n is 1, compound (R1) is an amino acid, and 1 When n is 2 or more, the compound (R1) is a peptide. 1 The upper limit of n is not particularly limited as long as the amination step proceeds, but is, for example, 100 or less, 80 or less, 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, 15 or less, 12 or less, or 10 or less. 1 Specific examples are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, etc.

[0062] n 2 is an integer of 1 or more, which represents the number of amino acid units in the brackets [ ] of general formula (R2). 2 When n is 1, compound (R2) is an amino acid, and 2 When n is 2 or more, the compound (R2) is a peptide. 2 The upper limit of n is not particularly limited as long as the amination step proceeds, and examples of the upper limit include 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. 2 is preferably 1, i.e., compound (R2) is preferably an amino acid. Without being bound by theory, the present inventors believe that n 2 When R2 is 1, that is, when compound (R2) is an amino acid, it reacts with the aluminum compound of formula (A) to form a cyclized intermediate containing an aluminum atom, which is presumably one of the factors that improves the reaction efficiency.

[0063] Needless to say, n 1 If is 2 or more, R that defines the structure in [ ] 11 , R 12 , R 13 , A 11 , A12 , p11, and p12 may be the same or different among multiple amino acid units. 2 If is 2 or more, R that defines the structure in [ ] 21 , R 22 , R 23 , A 21 , A 22 , p21, and p22 may be the same or different among multiple amino acid units. That is, when compound (R1) and / or compound (R2) are peptides, multiple amino acid units constituting the peptide may be the same or different.

[0064] In compound (R1), T a represents a hydrogen atom or a monovalent substituent. In the case of a monovalent substituent, the type thereof is not particularly limited, but R 13 and R 23 In addition to the above-mentioned groups, the protecting group of the amino group (hereinafter referred to as PG a The protecting group for the amino group is PG. a There are no particular limitations on the protecting group PG as long as it can protect the amino group from reaction in the amidation reaction and can be converted to an amino group by deprotection after the reaction. a The silicon-containing hydrophobic substituent TAG(Si) will be described in detail later.

[0065] In compound (R2), T b represents a hydrogen atom or a monovalent substituent. In the case of a monovalent substituent, the type thereof is not particularly limited, but R 13 and R 23 In addition to the above-mentioned groups, a protecting group for a carboxyl group (hereinafter referred to as PG b The protecting group for the carboxyl group is PG. bThere are no particular limitations on the protecting group PG as long as it can protect the carboxyl group from reaction in the amidation reaction and can be converted to a carboxyl group by deprotection after the reaction. b The silicon-containing hydrophobic substituent TAG(Si) will be described in detail later.

[0066] In compound (R2), the amino group on the left side of the formula may form a salt with another acid. In this case, the other acid may include, but is not limited to, aliphatic carboxylic acids having 1 to 5 carbon atoms such as acetic acid and propionic acid; trifluoroacetic acid, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, sulfonic acid, etc.

[0067] The above-mentioned substrate compounds (R1) and (R2) may each be used as a single compound, or as a mixture of two or more compounds in any combination and ratio.

[0068] In addition, a part or all of the above-mentioned substrate compound (R1) or (R2) may be linked and fixed to a support such as a substrate or resin at any of the substituents. In this case, the type of the support such as the substrate or resin is not limited. Any conventionally known support such as a substrate or resin can be used without substantially inhibiting the amide bond reaction in the production method of the present invention and within the scope of the present invention. The mode of linking and fixing the substrate compound to a support such as a substrate or resin is not limited in any way, but it is preferable to form a covalent bond between any of the substituents of the substrate compound and the substituents present on the support such as the substrate or resin. The type of each substituent and the method of forming the covalent bond are also not limited in any way. Any conventionally known type of substituent and method of forming the covalent bond can be used without substantially inhibiting the amide bond reaction in the production method of the present invention and within the scope of the present invention. The substrate compound may be linked and fixed to a support such as a substrate or resin by a covalent bond using a carboxyl group or amino group (other than the carboxylate group or amino group that is the target of the amide bond reaction) of the substrate compound. This embodiment can be considered similar to an embodiment in which a carboxyl group or an amino group (other than a carboxylate group or an amino group to be the target of amide bond formation) of a substrate compound is protected by introducing a protecting group.

[0069] Amino protecting groups: Amino protecting group PG aA wide variety of known linking groups are known. Examples include monovalent hydrocarbon groups which may have one or more substituents, and monovalent heterocyclic groups which may have one or more substituents. Among them, monovalent hydrocarbon groups which may have one or more substituents are preferred. However, a linking group may be present between such a hydrocarbon group or heterocyclic group and the nitrogen atom of the amino group it protects. Such linking groups are not limited, but are each independently selected from the linking groups shown below (note that in the following chemical formula, A each independently represents a monovalent hydrocarbon group or heterocyclic group which may have one or more substituents. When there are two A's in the same group, they may be the same or different).

[0070] [ka]

[0071] The protecting group usually has 1 or more, or 3 or more, and usually has 20 or less, or 15 or less.

[0072] Among these, the protecting group for the amino group is preferably one or more groups selected from the group consisting of monovalent hydrocarbon groups, acyl groups, hydrocarbonoxycarbonyl groups, hydrocarbonsulfonyl groups, and amide groups, each of which may have one or more substituents.

[0073] Specific examples of the protecting group for the amino group are listed below. Note that the name of the protecting group for the amino group includes not only the name of the functional group bonded to the nitrogen atom of the amino group, but also the name including the nitrogen atom, and both are included in the following names.

[0074] Specific examples of unsubstituted or substituted hydrocarbon groups include alkyl groups such as methyl, ethyl, and propyl groups; alkenyl groups such as ethenyl, propenyl, and allyl groups; alkynyl groups such as propargyl groups; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups; aryl groups such as phenyl, benzyl, paramethoxybenzyl, tolyl, and triphenylmethyl (toroc) groups; and substituted hydrocarbon groups such as cyanomethyl groups. The number of carbon atoms is usually 1 or more, or 3 or more, and usually 20 or less, or 15 or less.

[0075] Specific examples of the unsubstituted or substituted acyl group include a benzoyl group (Bz), an ortho-methoxybenzoyl group, a 2,6-dimethoxybenzoyl group, a para-methoxybenzoyl group (PMPCO), a cinnamoyl group, and a phthaloyl group (Phth).

[0076] Specific examples of unsubstituted or substituted hydrocarbonoxycarbonyl groups include a tert-butoxycarbonyl group (Boc), a benzyloxycarbonyl group (Cbz or Z), a methoxycarbonyl group, an ethoxycarbonyl group, a 2-trimethylsilylethoxycarbonyl group, a 2-phenylethoxycarbonyl group, a 1-(1-adamantyl)-1-methylethoxycarbonyl group, a 1-(3,5-di-t-butylphenyl)-1-methylethoxycarbonyl group, a vinyloxycarbonyl group, an allyloxycarbonyl group, Examples of such groups include an allyl group (Alloc), an N-hydroxypiperidinyloxycarbonyl group, a p-methoxybenzyloxycarbonyl group, a p-nitrobenzyloxycarbonyl group, a 2-(1,3-dithianyl)methoxycarbonyl group, a m-nitrophenoxycarbonyl group, a 3,5-dimethoxybenzyloxycarbonyl group, an o-nitrobenzyloxycarbonyl group, a 2,2,2-trichloroethoxycarbonyl group (Troc), and a 9-fluorenylmethyloxycarbonyl group (Fmoc).

[0077] Specific examples of unsubstituted or substituted hydrocarbon sulfonyl groups include a methanesulfonyl group (Ms), a toluenesulfonyl group (Ts), and a 2- or 4-nitrobenzenesulfonyl group (Ns).

[0078] Specific examples of unsubstituted or substituted amide groups include acetamide, o-(benzoyloxymethyl)benzamide, 2-[(t-butyldiphenylsiloxy)methyl]benzamide, 2-toluenesulfonamide, 4-toluenesulfonamide, 2-nitrobenzenesulfonamide, 4-nitrobenzenesulfonamide, tert-butylsulfinylamide, 4-toluenesulfonamide, 2-(trimethylsilyl)ethanesulfonamide, benzylsulfonamide, and the like.

[0079] In addition, from the viewpoint of the deprotection technique, examples of the protecting group for an amino group include a protecting group that can be deprotected by at least one technique selected from the group consisting of deprotection by hydrogenation, deprotection by a weak acid, deprotection by a fluoride ion, deprotection by a one-electron oxidizing agent, deprotection by hydrazine, and deprotection by oxygen.

[0080] Preferred specific examples of the protecting group for the amino group include a mesyl group (Ms), a tert-butoxycarbonyl group (Boc), a benzyl group (Bn or Bzl), a benzyloxycarbonyl group (Cbz), a benzoyl group (Bz), a paramethoxybenzyl group (PMB), a 2,2,2-trichloroethoxycarbonyl group (Troc), an allyloxycarbonyl group (Alloc), a 2,4-dinitrophenyl group (2,4-DNP), a phthaloyl group (Phth), a paramethoxybenzoyl group (PMPCO), a cinnamoyl group, a toluenesulfonyl group (Ts), a 2- or 4-nitrobenzenesulfonyl group (Ns), a cyanomethyl group, a 9-fluorenylmethyloxycarbonyl group (Fmoc), etc. This is because these protecting groups can easily protect an amino group and can be removed under relatively mild conditions, as described above.

[0081] More preferred specific examples of the amino-protecting group include a mesyl group (Ms), a tert-butoxycarbonyl group (Boc), a benzyloxycarbonyl group (Cbz), a benzyl group (Bn), a paramethoxybenzyl group (PMB), a 2,2,2-trichloroethoxycarbonyl group (Troc), an allyloxycarbonyl group (Alloc), a paramethoxybenzoyl group (PMPCO), a benzoyl group (Bz), a cyanomethyl group, a cinnamoyl group, a 2- or 4-nitrobenzenesulfonyl group (Ns), a toluenesulfonyl group (Ts), a phthaloyl group (Phth), a 2,4-dinitrophenyl group (2,4-DNP), a 9-fluorenylmethyloxycarbonyl group (Fmoc), and the like.

[0082] Carboxyl protecting groups: Carboxyl protecting group PG b Various types are known as the substituent. Examples include monovalent hydrocarbon groups or heterocyclic groups which may have one or more substituents. In addition, when the substituent is present, the type is as described above. Specific examples of the number of the substituents are, for example, 5, 4, 3, 2, 1, or 0.

[0083] The upper limit of the number of carbon atoms in the hydrocarbon group (including the substituent if any) is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of hydrocarbon group, but is 1 or more for an alkyl group, 2 or more for an alkenyl group or alkynyl group, and 3 or more for a cycloalkyl group, for example, 4 or more or 5 or more. Specific examples of the number of atoms are, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0084] The upper limit of the total number of carbon atoms and heteroatoms (including substituents, if any) in the heterocyclic group is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of heterocyclic structure, but is usually 3 or more, for example, 4 or more, or 5 or more. Specific examples of the number of atoms are, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0085] Specific examples of the protecting group for the carboxyl group include, but are not limited to, the following:

[0086] Alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, decyl, and nonyl; Alkenyl groups such as ethenyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl; Alkynyl groups, such as propargyl groups; Cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclooctyl, and spirooctyl groups; Aryl groups such as phenyl, benzyl, tolyl, naphthyl, and anthracenyl; Furanyl group, thiophenyl group, pyranyl group, pyrrolinyl group, pyrrolyl group, 2,3-dihydro-1H-pyrrolyl group, piperidinyl group, piperazinyl group, homopiperazinyl group, morpholino group, thiomorpholino group, 1,2,4,6-tetrahydropyridyl group, hexahydropyrimidyl group, hexahydropyridazyl group, 1,2,4,6-tetrahydropyridyl group, 1,2,4,6-tetrahydropyridazyl group, 3,4-dihydropyridyl group, imidazolyl group, 4,5-dihydro-1H-imidazolyl group heterocyclic groups such as an alkyl group, a 2,3-dihydro-1H-imidazolyl group, a pyrazolyl group, a 4,5-dihydro-1H-pyrazolyl group, a 2,3-dihydro-1H-pyrazolyl group, an oxazolyl group, a 4,5-dihydro-1,3-oxazolyl group, a 2,3-dihydro-1,3-oxazolyl group, a 2,5-dihydro-1,3-oxazolyl group, a thiazolyl group, a 4,5-dihydro-1,3-thiazolyl group, a 2,3-dihydro-1,3-thiazolyl group, a 2,5-dihydro-1,3-thiazolyl group, and a carbazolyl group; Silicon-based protecting groups such as a trimethylsilyl (TMS) group, a triethylsilyl (TES) group, a triisopropylsilyl (TIPS) group, a tritert-butylsilyl (TBS) group, a tert-butyldiphenylsilyl (TBDPS) group, a tris(trialkylsilyl)silyl group, and the like.

[0087] Silicon-containing hydrophobic substituent TAG(Si): One of the main features of the method of the present invention is that it satisfies the following (i) and / or (ii). (i) T in formula (R1) a is a group represented by -OC(=O)-TAG(Si). (ii) T in formula (R2) b is a group represented by -TAG(Si). Here, -TAG(Si) is a silicon-containing hydrophobic substituent having a structure represented by the following formula (T). [ka]

[0088] In other words, one of the main features of the method of the present invention is that the amino group on the left side of the formula of the amino acid or peptide compound of formula (R1) and / or the carboxyl group on the right side of the formula of the amino acid ester or peptide ester compound of formula (R2) are protected by a silicon-containing hydrophobic substituent TAG(Si) (or a group containing same) of the above formula (T).

[0089] In formula (T), R x represents a divalent, trivalent, or tetravalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group, which may have one or more substituents. The divalent, trivalent, or tetravalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group may be any divalent, trivalent, or tetravalent group obtained by removing any one, two, or three hydrogen atoms from the monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group. In addition, when it has a substituent, the type thereof is as described above. Specific examples of the number of substituents are, for example, 5, 4, 3, 2, 1, or 0.

[0090] R x The upper limit of the number of carbon atoms in the divalent, trivalent, or tetravalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group (including the substituent if any) is, for example, 20 or less, 15 or less, 10 or less, 8 or less, or 6 or less. The lower limit varies depending on the type of hydrocarbon group, but is 1 or more in the case of an alkyl group, 2 or more in the case of an alkenyl group or an alkynyl group, and 3 or more in the case of a cycloalkyl group, for example, 4 or more, or 5 or more. Specific examples of the number of atoms are, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0091] Among them, R x is preferably a divalent aliphatic hydrocarbon having two or more carbon atoms. x may be a divalent aliphatic hydrocarbon having two or more carbon atoms and containing one or more unsaturated bonds (double or triple bonds). x is preferably -C≡C-.

[0092] In formula (T), R z1 ~R z9 Each independently represents a monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, silicon-containing hydrocarbon group, or heterocyclic group, which may have one or more substituents. The monovalent aliphatic and / or aromatic hydrocarbon group (alkyl group, alkenyl group, alkynyl group, cycloalkyl group, cycloalkenyl group, cycloalkynyl group, aryl group, arylalkyl group, alkylaryl group, etc.) or heterocyclic group is as described separately. Specific examples include, but are not limited to, the following.

[0093] Alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, decyl, and nonyl; Alkenyl groups such as ethenyl, propenyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl; Alkynyl groups, such as propargyl groups; Cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclooctyl, and spirooctyl groups; Aryl groups such as phenyl, benzyl, tolyl, naphthyl, and anthracenyl; Furanyl, thiophenyl, pyranyl, pyrrolinyl, pyrrolyl, 2,3-dihydro-1H-pyrrolyl, piperidinyl, piperazinyl, homopiperazinyl, morpholino, thiomorpholino, 1,2,4,6-tetrahydropyridyl, hexahydropyrimidyl, hexahydropyridazyl, 1,2,4,6-tetrahydropyridyl, 1,2,4,6-tetrahydropyridazyl, 3,4-dihydropyridyl, imidazolyl, 4,5-dihydro-1H-imidazolyl heterocyclic groups such as a 2,3-dihydro-1H-imidazolyl group, a pyrazolyl group, a 4,5-dihydro-1H-pyrazolyl group, a 2,3-dihydro-1H-pyrazolyl group, an oxazolyl group, a 4,5-dihydro-1,3-oxazolyl group, a 2,3-dihydro-1,3-oxazolyl group, a 2,5-dihydro-1,3-oxazolyl group, a thiazolyl group, a 4,5-dihydro-1,3-thiazolyl group, a 2,3-dihydro-1,3-thiazolyl group, a 2,5-dihydro-1,3-thiazolyl group, a carbazolyl group, and the like;

[0094] Examples of the monovalent silicon-containing hydrocarbon group include groups obtained by replacing any one or more carbon atoms of a monovalent aliphatic hydrocarbon group or aromatic hydrocarbon group with a silicon atom.

[0095] R z1 ~R z9 When one or more of R are monovalent aliphatic or aromatic hydrocarbon groups, the number of carbon atoms (including the substituent if any) is independently 40 or less, 35 or less, 30 or less, or 25 or less, for example. The lower limit varies depending on the type of hydrocarbon group, but is 1 or more for alkyl groups, 2 or more for alkenyl or alkynyl groups, and 3 or more for cycloalkyl groups, for example 4 or more, or 5 or more. z1 , R z2 , and / or R z3When is a monovalent heterocyclic group, the upper limit of the total number of carbon atoms and heteroatoms (including the substituents if any) is, for example, 40 or less, 35 or less, 30 or less, or 25 or less. The lower limit varies depending on the type of heterocyclic structure, but is usually 3 or more, for example, 4 or more, or 5 or more. Specific examples of the number of atoms are, for example, 1, 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, or 40.

[0096] In the present invention, R z1 ~R z9 Among these, at least one, preferably at least two, more preferably at least three are aliphatic hydrocarbon groups having 7 or more carbon atoms, which may have one or more substituents. The aliphatic hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples of such unsubstituted or substituted aliphatic hydrocarbon groups having 7 or more carbon atoms include alkyl groups (linear or branched) such as tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, and heptyl groups, alkenyl or alkynyl groups obtained by unsaturating one or more of these carbon-carbon bonds, and groups obtained by substituting these groups with one or more substituents. When these aliphatic hydrocarbon groups have a substituent, the type of the substituent is as described above.

[0097] Among them, R z1 ~R z9 It is preferable that at least 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, or all 9 of R are aliphatic hydrocarbon groups having 7 or more carbon atoms. z1 ~R z3 One or more of the following (particularly two or more, especially all three): R z4 ~R z6 One or more of the following (particularly two or more, especially all three): and R z7 ~R z9Of these, it is preferable that one or more (particularly two or more, and particularly all three) are an aliphatic hydrocarbon group having 7 or more carbon atoms which may have one or more substituents.

[0098] In addition, when the silicon-containing hydrophobic substituent TAG(Si) of the above formula (T) protects the protecting group of the terminal amino group on the left side of the formula of the amino acid or peptide compound of formula (R1), it is usually the terminal amino radical -N(R 13 )- is bonded to the group -TAG(Si) via the carbonyloxy group -C(=O)-O-, and -N(R 13 On the other hand, when the silicon-containing hydrophobic substituent TAG(Si) of the above formula (T) protects the carboxyl group on the right side of the formula of the terminal amino acid ester or peptide ester compound of formula (R2), the terminal carboxyl radical -C(=O)-O- of the compound of formula (R2) usually bonds directly to the group -TAG(Si) to form a structure represented by -C(=O)-O-TAG(Si).

[0099] In the method of the present invention, the terminal amino group of the amino acid or peptide compound of formula (R1) and / or the terminal carboxyl group of the amino acid or peptide compound of formula (R2) are protected with a silicon-containing hydrophobic substituent TAG(Si) having such a specific structure, and then these compounds are used to elongate the peptide chain through a peptide bond reaction, thereby preventing a decrease in the solubility of the peptide chain in organic solvents, and thus improving the reactivity of the peptide chain and the operability in the purification process. The reason for this, without being bound by theory, is believed to be that the substituent R z1 , R z2 , and / or R z3It is believed that the effect of reducing polarity is enhanced by including a low polar long-chain aliphatic or aromatic ring or heterocyclic ring as R and including a silicon atom. In addition, unlike the silyl ester group described in the aforementioned Non-Patent Document 7 (Org. Process Res. Dev. 2021, Vol. 25, p. 2029-2038), a silicon atom is not directly bonded to the terminal carboxyl group of an amino acid or peptide compound, but is bonded to R x Since the bond is formed via the group and the L group, there is little risk of deprotection of the ester group occurring depending on the reaction conditions, and the compound can be used under a variety of reaction conditions.

[0100] Furthermore, such a silicon-containing hydrophobic substituent remains stable without being decomposed under the conditions for deprotection of an amino group-protecting group, and can be efficiently removed by hydrolysis after completion of peptide elongation. Therefore, by carrying out a peptide elongation reaction using this silicon-containing hydrophobic substituent, it is possible to obtain a desired peptide with high efficiency.

[0101] Another major advantage of the method of the present invention is that the silicon-containing hydrophobic substituent TAG(Si) can also be used to protect the N-terminal amino group of the amino acid or peptide compound of formula (R1). Generally, peptide bond formation reactions are carried out by N-terminal extension. For example, in solid-phase synthesis, all peptide bonds with resins are connected to the C-terminus of the peptide, so there is no other way to carry out the peptide extension reaction than on the N-terminus side of the peptide. Also, in liquid-phase synthesis, N-terminal protecting groups are overwhelmingly lacking in diversity compared to C-terminal protecting groups such as Fmoc, Boc, Cbz, Trt, and Ac. In addition, these protecting groups focus on short-chain peptide synthesis and are almost ineffective in reducing polarity to long-chain peptides. From these perspectives, the synthesis of N-terminal protecting groups with a view to long-chain peptide synthesis is important, and the silicon-containing hydrophobic substituent TAG(Si) of the present invention is very useful in this respect.

[0102] Silane compounds: In the production method (1) of the present invention, a silane compound may be present in the reaction system. By carrying out the reaction in the presence of a silane compound in the reaction system, various advantages such as improved reaction yield and improved stereoselectivity may be obtained.

[0103] Examples of the silane compound include various tris{halo (preferably fluorine)-substituted alkyl}silanes such as HSi(OCH(CF3)2)3, HSi(OCH2CF3)3, HSi(OCH2CF2CF2H)3, and HSi(OCH2CF2CF2CF2CF2H)3, as well as trimethylsilyl trifluoromethanesulfonate (TMS-OTf), 1-(trimethylsilyl)imidazole (TMSIM), dimethylethylsilylimidazole (DMESI), dimethylisopropylsilylimidazole (DMIPSI), 1-(tert-butyldimethylsilyl)imidazole (TBSIM), 1-(trimethylsilyl)triazole, 1-(ter t-butyldimethylsilyl)triazole, dimethylsilylimidazole, dimethylsilyl(2-methyl)imidazole, trimethylbromosilane (TMBS), trimethylchlorosilane (TMCS), N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), N,O-bis(trimethylsilyl)acetamide (BSA), N-(trimethylsilyl)dimethylamine (TMSDMA), N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA), hexamethyldisilazane (HMDS), etc. These may be used alone or in any combination and ratio of two or more.

[0104] Lewis acid catalyst: In the production method (1) of the present invention, a Lewis acid catalyst may be present in the reaction system. By carrying out the reaction in the presence of a Lewis acid catalyst in the reaction system, various advantages such as improved reaction yield and improved stereoselectivity may be obtained. However, on the other hand, when a Lewis acid catalyst is used, it may be necessary to separate and remove the Lewis acid catalyst from the reaction product. Therefore, it is preferable to appropriately determine whether or not to use a Lewis acid catalyst, taking into consideration the purpose of using the production method of the present invention, etc.

[0105] When using a Lewis acid catalyst in the production method of the present invention, the type is not limited, but it is preferable that the catalyst is a metal compound that functions as a Lewis acid. Metal elements constituting the metal compound include various metals belonging to Groups 2 to 15 of the Periodic Table of Elements. Specific examples of metal elements include boron, magnesium, gallium, indium, silicon, calcium, lead, bismuth, mercury, transition metals, lanthanoid elements, etc. Specific examples of transition metals include scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, tin, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, thallium, etc. Specific examples of lanthanoid elements include lanthanum, cerium, neodymium, samarium, europium, gadolinium, holmium, erbium, thulium, ytterbium, etc. Among these, from the viewpoint of exerting an excellent reaction promotion effect and producing an amide compound with high stereoselectivity, one or more selected from titanium, zirconium, hafnium, tantalum, niobium, boron, vanadium, tungsten, neodymium, iron, lead, cobalt, copper, silver, palladium, tin, thallium, etc. are preferred, and one or more selected from titanium, zirconium, hafnium, tantalum, niobium, etc. are preferred. The metal compound may contain one or more metal elements. When the metal compound contains two or more metal elements, these may be the same type of element, or two or more different metal elements.

[0106] The ligand constituting the metal compound is appropriately selected depending on the type of metal. Specific examples of the ligand include substituted or unsubstituted linear or branched alkoxy groups having 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a trifluoroethoxy group, or a trichloroethoxy group; halogen atoms, such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; an aryloxy group having 1 to 10 carbon atoms; an acetylacetonate group (acac), an acetoxy group (AcO), or a trifluoromethanesulfonate group (TfO); a substituted or unsubstituted linear or branched alkyl group having 1 to 10 carbon atoms; a phenyl group, an oxygen atom, a sulfur atom, a -SR group (wherein R is a substituent, and examples of the substituent include a substituted or unsubstituted hydrocarbon group having about 1 to 20 carbon atoms), a -NRR' group (wherein R and R' are each independently a hydrogen atom or a substituent, and examples of the substituent include a substituted or unsubstituted hydrocarbon group having about 1 to 20 carbon atoms), and a cyclopentadienyl (Cp) group.

[0107] Among them, the metal compound is preferably a titanium compound, a zirconium compound, a hafnium compound, a tantalum compound, or a niobium compound. Specific examples of each are given below. These may be used alone or in any combination and ratio of two or more.

[0108] A specific example of a titanium compound is TiX. 1 4 (but 4 X 1 Each of X is independently a ligand exemplified above. 1 X may be the same ligand or may be different from each other. 1 When X is an alkoxy group, it is preferably a straight or branched alkoxy group having 1 to 10 carbon atoms, more preferably a straight or branched alkoxy group having 1 to 5 carbon atoms, and even more preferably a straight or branched alkoxy group having 1 to 4 carbon atoms. 1When X is an aryloxy group, it is preferably an aryloxy group having 1 to 20 carbon atoms, more preferably an aryloxy group having 1 to 15 carbon atoms, and even more preferably an aryloxy group having 1 to 10 carbon atoms. These ligands may further have a substituent. 1 When is a halogen atom, preferred examples include a chlorine atom, a bromine atom, etc. Among these, for example, Ti(OMe)4, Ti(OEt)4, Ti(OPr)4, Ti(Oi-Pr)4, Ti(OBu)4, Ti(Ot-Bu)4, Ti(OCH2CH(Et)Bu)4, CpTiCl3, Cp2TiCl2, Cp2Ti(OTf)2, (i-PrO)2TiCl2, (i-PrO)3TiCl, etc. are preferred.

[0109] Specific examples of zirconium compounds include ZrX 2 4 (but 4 X 2 Each of X is independently a ligand exemplified above. 2 X may be the same ligand or may be different from each other. 2 When X is an alkoxy group, it is preferably a straight or branched alkoxy group having 1 to 10 carbon atoms, more preferably a straight or branched alkoxy group having 1 to 5 carbon atoms, and even more preferably a straight or branched alkoxy group having 1 to 4 carbon atoms. 2 When X is an aryloxy group, it is preferably an aryloxy group having 1 to 20 carbon atoms, more preferably an aryloxy group having 1 to 15 carbon atoms, and even more preferably an aryloxy group having 1 to 10 carbon atoms. These ligands may further have a substituent. 2 When is a halogen atom, preferred examples include a chlorine atom, a bromine atom, etc. Among these, for example, Zr(OMe)4, Zr(OEt)4, Zr(OPr)4, Zr(Oi-Pr)4, Zr(OBu)4, Zr(Ot-Bu)4, Zr(OCH2CH(Et)Bu)4, CpZrCl3, Cp2ZrCl2, Cp2Zr(OTf)2, (i-PrO)2ZrCl2, (i-PrO)3ZrCl, etc. are preferred.

[0110] Specific examples of hafnium compounds include HfX 3 4 (but 4 X 3Each of X is independently a ligand exemplified above. 3 may be the same ligand or may be different from each other. 3 When X is an alkoxy group, it is preferably a straight or branched alkoxy group having 1 to 10 carbon atoms, more preferably a straight or branched alkoxy group having 1 to 5 carbon atoms, and even more preferably a straight or branched alkoxy group having 1 to 4 carbon atoms. 3 When X is an aryloxy group, it is preferably an aryloxy group having 1 to 20 carbon atoms, more preferably an aryloxy group having 1 to 15 carbon atoms, and even more preferably an aryloxy group having 1 to 10 carbon atoms. These ligands may further have a substituent. 3 When is a halogen atom, preferred examples include a chlorine atom, a bromine atom, etc. Among these, for example, HfCp2Cl2, HfCpCl3, HfCl4, etc. are preferred.

[0111] Specific examples of tantalum compounds include TaX 4 5 (However, 5 X 4 Each of X is independently a ligand exemplified above. 4 X may be the same ligand or may be different from each other. 4 When X is an alkoxy group, it is preferably a straight or branched alkoxy group having 1 to 10 carbon atoms, more preferably a straight or branched alkoxy group having 1 to 5 carbon atoms, and even more preferably a straight or branched alkoxy group having 1 to 3 carbon atoms. 4 When X is an aryloxy group, it is preferably an aryloxy group having 1 to 20 carbon atoms, more preferably an aryloxy group having 1 to 15 carbon atoms, and even more preferably an aryloxy group having 1 to 10 carbon atoms. These ligands may further have a substituent. 4 When X is a halogen atom, preferred examples include a chlorine atom and a bromine atom. Among these, tantalum alkoxide compounds (e.g., X 4 is an alkoxy group), and the like are preferable, for example, Ta(OMe)5, Ta(OEt)5, Ta(OBu)5, Ta(NMe2)5, Ta(acac)(OEt)4, TaCl5, TaCl4(THF), TaBr5, and the like are preferable.4 Compounds in which is oxygen, i.e., Ta2O5, can also be used.

[0112] Specific examples of niobium compounds include NbX 5 5 (However, 5 X 5 Each of X is independently a ligand exemplified above. 5 X may be the same ligand or may be different from each other. 5 When X is an alkoxy group, it is preferably a straight or branched alkoxy group having 1 to 10 carbon atoms, more preferably a straight or branched alkoxy group having 1 to 5 carbon atoms, and even more preferably a straight or branched alkoxy group having 1 to 3 carbon atoms. 5 When X is an aryloxy group, it is preferably an aryloxy group having 1 to 20 carbon atoms, more preferably an aryloxy group having 1 to 15 carbon atoms, and even more preferably an aryloxy group having 1 to 10 carbon atoms. These ligands may further have a substituent. 5 When X is a halogen atom, preferred examples include a chlorine atom and a bromine atom. Among these, niobium alkoxide compounds (e.g., X 5 is an alkoxy group), for example, NbCl4(THF), NbCl5, Nb(OMe)5, Nb(OEt)5, etc. are preferred. 5 Compounds in which Nb2O5 is oxygen can also be used.

[0113] The Lewis acid catalyst may be supported on a carrier. The carrier for supporting the Lewis acid catalyst is not particularly limited, and any known carrier can be used. Also, any known method can be used as a method for supporting the Lewis acid catalyst on a carrier.

[0114] Other Ingredients: In the production method (1) of the present invention, other components may be present in addition to the substrate compounds, the amino acid or peptide compound of the formula (R1) and the amino acid ester or peptide ester compound of the formula (R2), the aluminum compound of the formula (A) as the amidation reactant, and optionally a silane compound and / or a Lewis acid catalyst. Examples of such other components include, but are not limited to, conventional catalysts (other than Lewis acid catalysts) that can be used in amidation reactions, bases, phosphorus compounds, solvents, etc. Any one of these may be used alone, or two or more may be used in any combination and ratio.

[0115] Examples of the catalyst (other than the Lewis acid catalyst) include methylaluminum bis(4-bromo-2,6-di-tert-butylphenoxide) (MABR), trimethylsilyl trifluoromethanesulfonate (TMS-OTf), methylaluminum bis(2,6-di-tert-butylphenoxide) (MAD), etc. Any one of these may be used alone, or two or more of them may be used in any combination and ratio.

[0116] The type of base is not limited, and a known base that is known to improve the reaction efficiency can be used. Examples of such bases include amines having 1 to 4 linear or branched alkyl groups having 1 to 10 carbon atoms, such as tetrabutylammonium fluoride (TBAF), triethylamine (Et3N), diisopropylamine (i-Pr2NH), and diisopropylethylamine (i-Pr2EtN), and inorganic bases such as cesium fluoride. These may be used alone or in any combination and ratio of two or more.

[0117] Examples of phosphorus compounds include phosphine compounds (e.g., trimethylphosphine, triethylphosphine, tripropylphosphine, trimethyloxyphosphine, triethyloxyphosphine, tripropyloxyphosphine, triphenylphosphine, trinaphthylphosphine, triphenyloxyphosphine, tris(4-methylphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-fluorophenyl)phosphine, tris(4-methylphenyloxy)phosphine, tris(4-methoxyphenyloxy)phosphine, tris(4-fluorophenyloxy)phosphine, etc.), phosphate compounds (e.g., trimethyl phosphate, triethyl phosphate, tripropyl phosphate, trimethyloxy phosphate, , triethyloxy phosphate, tripropyloxy phosphate, triphenyl phosphate, trinaphthyl phosphate, triphenyloxy phosphate, tris(4-methylphenyl)phosphate, tris(4-methoxyphenyl)phosphate, tris(4-fluorophenyl)phosphate, tris(4-methylphenyloxy)phosphate, tris(4-methoxyphenyloxy)phosphate, tris(4-fluorophenyloxy)phosphate, etc.), polyvalent phosphine compounds or polyvalent phosphate compounds (e.g., 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), 5,5'-bis(diphenylphosphino)-4,4'-bi-1,3-benzodioxole (SEGPHOS), etc.). Any one of these may be used alone, or two or more may be used in any combination and ratio.

[0118] In addition, from the viewpoint of increasing the reaction efficiency, a solvent may be used during the reaction. The solvent is not particularly limited, but examples thereof include aqueous solvents and organic solvents. The organic solvent is not limited, but examples thereof include aromatic hydrocarbons such as toluene and xylene, ethers such as pentane, petroleum ether, tetrahydrofuran (THF), 1-methyltetrahydrofuran (1-MeTHF), diisopropyl ether (i-Pr2O), diethyl ether (Et2O), and cyclopentyl methyl ether (CPME), nitrogen-based organic solvents such as acetonitrile (MeCN), chlorine-based organic solvents such as dichloromethane (DCM), esters such as ethyl acetate (AcOEt), and organic acids such as acetic acid. These solvents may be used alone or in combination of two or more.

[0119] Reaction procedure: In the production method (1) of the present invention, the amino acid or peptide compound of the formula (R1) and the amino acid ester or peptide ester compound of the formula (R2), which are substrate compounds, may be mixed with the aluminum compound of the formula (A), which is an amidation reactant, and reacted. When a silane compound, a Lewis acid catalyst, and / or other components (catalysts other than Lewis acid catalysts, bases, and / or phosphorus compounds, etc.) are used as optional components, they may be mixed with the substrate compound and the amidation reactant. When a solvent is used optionally, the above components may be added to the solvent and mixed in the solvent.

[0120] Incidentally, with respect to any of the above components, the entire amount may be added to the system all at once, or may be added to the system in several batches, or may be added to the system in small amounts continuously.

[0121] Usage ratio of each ingredient: In the production method (1) of the present invention, the amounts of each component used are not limited, but are preferably as follows.

[0122] The ratio of the amount of the amino acid or peptide compound of formula (R1) to the amino acid ester or peptide ester compound of formula (R2) is not particularly limited, but the compound of formula (R2) can be used in a range of, for example, 0.1 moles or more, or 0.2 moles or more, or 0.3 moles or more, or 0.4 moles or more, or 0.5 moles or more, and for example, 20 moles or less, 10 moles or less, 5 moles or less, 4 moles or less, or 3 moles or less, relative to 1 mole of the compound of formula (R1). It is preferable to use more of the compound of formula (R2) than the compound of formula (R1) in terms of increasing the reaction efficiency. Specifically, the compound of formula (R2) can be used in an amount of about 2 moles relative to 1 mole of the compound of formula (R1). It is necessary to use at least 1 mole of the compound of formula (R1) and the compound of formula (R2) as substrates for the target production amount of the compound of formula (P1) to be produced.

[0123] The amount of the aluminum compound of formula (A) used is not particularly limited, so long as it is an amount that can induce the formation reaction of the peptide compound of formula (P1) from the amino acid or peptide compound of formula (R1) and the amino acid ester or peptide ester compound of formula (R2) through the implementation of the production method of the present invention. For example, the aluminum compound of formula (A) can be used in a range of, for example, 0.1 moles or more, or 0.2 moles or more, or 0.3 moles or more, or 0.4 moles or more, or 0.5 moles or more, and, for example, 20 moles or less, or 10 moles or less, or 5 moles or less, or 4 moles or less, or 3 moles or less, relative to 1 mole of the compound of formula (R1). When two or more aluminum compounds of formula (A) are used in combination, the total amount of the two or more aluminum compounds of formula (A) should be within the above range.

[0124] When a silane compound is used, the amount used is not particularly limited, but when the amount of the compound of formula (R1) used is taken as 100 mol%, for example, 0.1 mol% or more, or 0.2 mol% or more, or 0.3 mol% or more, and for example, 50 mol% or less, or 30 mol% or less, or 20 mol% or less, or 15 mol% or less of the silane compound can be used.

[0125] When a Lewis acid catalyst is used, the amount used is not particularly limited, but when the amount of the compound of formula (R1) used is taken as 100 mol%, for example, 0.1 mol% or more, or 0.2 mol% or more, or 0.3 mol% or more, and for example, 50 mol% or less, or 30 mol% or less, or 20 mol% or less, or 15 mol% or less of the Lewis acid catalyst can be used.

[0126] When other optional components are used, the amounts used may be appropriately adjusted with reference to conventional knowledge and the like, for example, in the past patent documents (Patent Documents 1 to 6) of the present inventors and others.

[0127] Reaction conditions: The reaction conditions in the production method (1) of the present invention are not limited as long as the reaction proceeds, and examples thereof are as follows.

[0128] The reaction temperature is not limited as long as the reaction proceeds, but can be, for example, 0°C or higher, or 10°C or higher, or 20°C or higher, and can be, for example, 100°C or lower, or 80°C or lower, or 60°C or lower.

[0129] The reaction pressure is not limited as long as the reaction proceeds, and the reaction may be carried out under reduced pressure, normal pressure, or increased pressure, but is usually carried out under normal pressure.

[0130] The reaction atmosphere is not limited as long as the reaction proceeds, but the reaction is usually carried out in an atmosphere of an inert gas such as argon or nitrogen.

[0131] The reaction time is also not limited as long as the reaction proceeds, but from the viewpoint of allowing the reaction to proceed sufficiently and efficiently, the reaction time can be, for example, 10 minutes or more, 20 minutes or more, or 30 minutes or more, and can be, for example, 80 hours or less, 60 hours or less, or 50 hours or less.

[0132] The production method (1) of the present invention may be carried out as a sequential method (batch method) or a continuous method (flow method). The specific details of the procedure for carrying out the sequential method (batch method) and the continuous method (flow method) are known in the art.

[0133] Post-processing (refining, recovery, etc.): The peptide compound (P1) obtained by the production method (1) of the present invention may be subjected to various post-treatments. For example, the produced peptide compound (P1) may be isolated and purified by a conventional method such as column chromatography or recrystallization. In addition, when the produced peptide compound (P1) has an amino group and / or a carboxyl group protected by a protecting group or the like, it may be deprotected according to the method described below. The produced peptide compound (P1) may be directly or after isolation and purification subjected to the latter step of the production method (2) of the present invention described below to produce a polypeptide having further extended amino acid residues.

[0134] [III. Other] The polypeptide compound of formula (P1) or formula (P2) obtained by the above-mentioned production method may be further subjected to various post-treatments.

[0135] For example, the polypeptide compound of formula (P1) or formula (P2) obtained by the above-mentioned production method can be isolated and purified by conventional methods such as column chromatography and recrystallization.

[0136] In addition, in the polypeptide compound of formula (P1) or formula (P2) obtained by the above-mentioned production method, the amino group protected by a protecting group can also be deprotected. The method for deprotecting the protected amino group is not particularly limited, and various methods can be used depending on the type of the protecting group. Examples include deprotection by hydrogenation, deprotection by weak acid, deprotection by fluoride ion, deprotection by one-electron oxidizing agent, deprotection by hydrazine, and deprotection by oxygen. In the case of deprotection by hydrogenation, examples include (a) a method of deprotection by reduction using a metal catalyst such as palladium, palladium-carbon, palladium hydroxide, palladium hydroxide-carbon, etc. as a reduction catalyst in the presence of hydrogen gas, and (b) a method of deprotection by reduction using a hydrogenation reducing agent such as sodium borohydride, lithium aluminum hydride, lithium borohydride, and diborane in the presence of a metal catalyst such as palladium, palladium-carbon, palladium hydroxide, palladium hydroxide-carbon, etc.

[0137] In addition, in the polypeptide compound of formula (P1) or formula (P2) obtained by the above-mentioned production method, the carboxyl group protected by a protecting group can also be deprotected. The method for deprotecting the protected carboxyl group is not particularly limited, and various methods can be used depending on the type of the protecting group. Examples include deprotection by hydrogenation, deprotection by a base, and deprotection by a weak acid. In the case of deprotection by a base, a deprotection method using a strong base such as lithium hydroxide, sodium hydroxide, or potassium hydroxide as the base can be mentioned.

[0138] In addition, the polypeptide compound of formula (P1) or formula (P2) obtained by the above-mentioned production method (after deprotection and / or conversion of the substituents, etc., as necessary) may be used as the peptide compound of formula (R1) and may be subjected again to the production method (1) or (2) of the present invention. Alternatively, the polypeptide compound of formula (P1) or formula (P2) obtained by the above-mentioned production method (after deprotection and / or conversion of the substituents, etc., as necessary) may be subjected to other conventionally known amidation methods or peptide production methods. In this way, other amino acids or peptides can be linked to the polypeptide compound of formula (P1) or formula (P2) by amide bonds to extend the amino acid residues and synthesize a larger polypeptide. By sequentially repeating such procedures, it is possible in principle to synthesize a polypeptide with any number of amino acid residues and amino acid sequence.

[0139] The present inventors have filed the following prior patent applications relating to amidation reactions for linking amino acids or peptides and methods for producing polypeptides using the same, and the methods for producing various polypeptides of the present invention can be carried out in appropriate combination with the amidation reactions and methods for producing polypeptides described in these prior patent applications, and / or can be modified as appropriate in consideration of the conditions for the amidation reactions and methods for producing polypeptides described in these prior patent applications. The descriptions of these prior patent applications are incorporated herein in their entirety by reference. (1) International Publication No. 2017 / 204144 (Patent Document 1) (2) International Publication No. 2018 / 199146 (Patent Document 2) (3) International Publication No. 2018 / 199147 (Patent Document 3) (4) International Publication No. 2019 / 208731 (Patent Document 4 mentioned above) (5) International Publication No. 2021 / 085635 (Patent Document 5) (6) International Publication No. 2021 / 085636 (Patent Document 6) (7) International Publication No. 2021 / 149814 (Patent Document 7) (8) International Publication No. 2022 / 190486 (Patent Document 8)

[0140] The silicon-containing hydrophobic substituent TAG(Si) used in the present invention is not limited to the protection of amino acids and peptides, and can also be used to protect various other organic molecules. Examples of such organic molecules include, but are not limited to, saccharides (various monosaccharides, disaccharides, polysaccharides, etc.), lipids (fatty acids, triacylglycerols, etc.), complex proteins (glycoproteins, lipoproteins, etc.), complex lipids (glycolipids, sphingolipids, phospholipids, etc.). The carboxyl and / or amino groups of these organic molecules can be protected by binding the silicon-containing hydrophobic substituent TAG(Si) to them by the above-mentioned method or a method similar thereto. In particular, various organic molecules that have low solubility in organic solvents, such as saccharides, glycoproteins, lipoproteins, etc., can be made more soluble in organic solvents by protecting the carboxyl and / or amino groups using the silicon-containing hydrophobic substituent TAG(Si) of the present invention. This makes it easier to use these organic molecules in various reactions (especially flow reactions). In addition, the silicon-containing hydrophobic substituent TAG(Si) of the present invention can be used to protect both carboxyl and amino groups, and therefore can protect whichever group does not interfere with the desired reaction depending on the type of reaction, and has the advantage of being extremely flexible. The application of the silicon-containing hydrophobic substituent TAG(Si) of the present invention to organic molecules other than amino acids or peptides is also within the scope of the present invention.

[0141] The present invention also covers the above-mentioned alcohol compound in which the silicon-containing hydrophobic substituent TAG(Si) is bonded to a hydroxyl group (OH), that is, an alcohol compound having a structure of the following formula (C0). [ka]

[0142] Furthermore, the present invention also covers compounds in which the carboxyl and / or amino groups of various organic molecules produced in such a protection reaction are protected with the silicon-containing hydrophobic substituent TAG(Si), i.e., compounds represented by, for example, the following formula (C1) or (C2). [ka]

[0143] [ka]

[0144] R in formula (C1) C1 , and R in formula (C2) C21 and R C22 R each independently represents any monovalent group. C1 , R C21 , and R C22 Specific examples of the substituent include the monovalent substituents described above, such as a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a thiol group, a sulfonic acid group, an amino group, an amido group, an imino group, an imido group, a hydrocarbon group, a heterocyclic group, a hydrocarbonoxy group, a hydrocarboncarbonyl group (acyl group), a hydrocarbonoxycarbonyl group, a hydrocarboncarbonyloxy group, a hydrocarbon-substituted amino group, a hydrocarbon-substituted aminocarbonyl group, a hydrocarboncarbonyl-substituted amino group, a hydrocarbon-substituted thiol group, a hydrocarbonsulfonyl group, a hydrocarbonoxysulfonyl group, a hydrocarbonsulfonyloxy group, a heterocyclicoxy group, a heterocycliccarbonyl group, a heterocyclicoxycarbonyl group, a heterocycliccarbonyloxy group, a heterocyclicamino group, a heterocyclicaminocarbonyl group, a heterocycliccarbonyl-substituted amino group, a heterocyclic-substituted thiol group, a heterocyclicsulfonyl group, a heterocyclicoxysulfonyl group, a heterocyclicsulfonyloxy group, and the like. C1 , R C21 , and R C22Other specific examples of the group include monovalent groups derived from the aforementioned organic molecules, such as sugars (various monosaccharides, disaccharides, polysaccharides, etc.), lipids (fatty acids, triacylglycerols, etc.), complex proteins (glycoproteins, lipoproteins, etc.), complex lipids (glycolipids, sphingolipids, phospholipids, etc.), and the like.

[0145] In particular, R in formula (C1) C1 is preferably a monovalent group obtained by removing a carboxyl group from any organic molecule having a carboxyl group. In this case, the compound of formula (C1) corresponds to a compound in which the carboxyl group of the organic molecule is protected with the silicon-containing hydrophobic substituent TAG(Si). Such a compound of formula (C1) can be obtained by reacting the organic molecule with an alcohol compound having the structure of formula (C0) by the above-mentioned known method.

[0146] In addition, R in formula (C2) C21 and R C22 At least one of the above is preferably a monovalent group obtained by removing an amino group from any organic molecule having an amino group. In this case, the compound of formula (C2) corresponds to a compound in which the amino group of the organic molecule is protected with the silicon-containing hydrophobic substituent TAG(Si). Such a compound of formula (C2) can be obtained by reacting the organic molecule with an alcohol compound having the structure of formula (C0) by the above-mentioned known method. EXAMPLES

[0147] The present invention will be described in more detail below with reference to examples. However, these examples are merely illustrative and are not intended to limit the present invention in any way.

[0148] I. Synthesis of TAG8 (2-(1,1,1,3,3,3-hexamethyl-2-(trimethylsilyl)trisilan-2-yl)ethan-1-ol) [ka]

[0149] 2-(1,1,1,3,3,3-Hexamethyl-2-(trimethylsilyl)trisilan-2-yl)ethan-1-ol (HOTAG8) was prepared according to literature procedures (Kopping et al., J. Org. Chem., 1992, 57:3994-4000 and U.S. Pat. No. 5,985,524).

[0150] II. Synthesis and Testing of TAG9 Synthesis of HOTAG9 (3-(1,1,1,3,3-hexamethyl-2-(trimethylsilyl)trisilan-2-yl)prop-2-yn-1-ol) [ka]

[0151] Tetrahydrofuran (8 mL) was added to a flame-dried flask containing a magnetic stir bar (Sm-CO) and compound 23 (210.3 mg, 1.5 mmol, 1.5 equiv) at -78 °C. n-Butyl lithium (1.55 M in hexanes, 0.97 mL, 1.5 mmol, 1.5 equiv) was added dropwise. The resulting mixture was stirred at -78 °C for 1.5 h, after which tris(trimethylsilyl)silyl chloride (283.1 mg, 1.0 mmol, 1.0 equiv) was added. After completion of the reaction, the reaction mixture was quenched with saturated ammonium chloride (NH4Cl) solution (10 mL) and the layers were separated. The aqueous layer was extracted with hexane (3 x 10 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated. The resulting residue was used in the next step without purification.

[0152] At room temperature, methanol (5 mL) and tetrahydrofuran (5 mL) were added to a flask containing a magnetic stir bar (Sm-Co) and the above residue, followed by p-toluenesulfonic acid monohydrate (19.0 mg, 0.1 mmol, 0.1 equiv). The reaction was stirred at room temperature for 2 hours. After completion of the reaction, the reaction mixture was concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc = 30:1 → 20:1 → 15:1) to give HOTAG9 as a pale yellow oil (total yield 63%, 190.5 mg).

[0153] Rf = 0.16 (hexanes / EtOAc = 20:1). 1 H NMR (400 MHz, CDCl3) δ 4.26 (s, 2H), 0.24 - 0.17 (m, 27H). 13 C NMR (100 MHz, CDCl3) δ 106.8, 84.2, 52.2, 0.3. IR (neat) 2951, 2894, 1398, 1244, 1037 cm -1 . HRMS (ESI) Calcd for C 12 H 30 OSi4Na [M+Na] + : 325.1271, Found: 325.1248.

[0154] Esterification test: Synthesis of Boc-Ala-OTAG9 (3-(1,1,1,3,3-hexamethyl-2-(trimethylsilyl)trisilan-2-yl)prop-2-yn-1-yl(tert-butoxycarbonyl) L-alaninate) [ka]

[0155] To a flame-dried 15 mL vial containing a magnetic stir bar (Sm-Co) and HOTAG9 (153.3 mg, 0.51 mmol, 1.0 equiv) at room temperature, dichloromethane (2.5 mL) was added, followed by Boc-Ala-OH (191.6 mg, 1.01 mmol, 2.0 equiv), followed by DMAP (74.2 mg, 0.61 mmol, 1.2 equiv) and DCC (209.0 mg, 1.01 mmol, 2.0 equiv). The reaction was stirred at room temperature for 2 h, then filtered, washed with dichloromethane (5 mL) and concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc = 20:1 → 15:1) to give Boc-Ala-OTAG9 as a colorless oil (96% yield, 231.5 mg).

[0156] Rf = 0.58 (hexanes / EtOAc = 5:1). [α] D 23= -27.10 (c 1.07, CHCl3). 1 1H NMR (400 MHz, CDCl3) δ 5.04 (d, J = 5.6 Hz, 1H), 4.82 (d, J = 15.6 Hz, 1H), 4.64 (d, J = 15.3 Hz, 1H), 4.43 - 4.23 (m, 1H), 1.43 (s, 9H), 1.38 (d, J = 7.2 Hz, 3H), 0.28 - 0.15 (m, 27H). 13 13C NMR (100 MHz, CDCl3) δ 172.5, 155.0, 101.3, 86.8, 79.8, 54.0, 49.1, 28.3, 18.6, 0.3. IR (neat) 2951, 2894, 1748, 1709, 1502, 1451, 1367, 1340, 1308, 1245, 1159 cm -1 . HRMS (ESI) Calcd for C 20 H 43 NO4Si4Na [M+Na] + : 496.2167, Found: 496.2167.

[0157] · Tolerance test; Synthesis of H-Ala-OTAG9 (3-(1,1,1,3,3-hexamethyl-2-(trimethylsilyl)trisilan-2-yl)prop-2-yn-1-yl L-alaninate)

Chem.

[0158] To a flame-dried 6 mL vial containing a magnetic stir bar (Sm-Co) and Boc-Ala-OTAG9 (23.7 mg, 0.05 mmol, 1.0 equiv) at room temperature, dichloromethane (0.05 mL) was added followed by hydrochloric acid solution (4.0 M in dioxane, 0.125 mL, 0.5 mmol, 10.0 equiv). After completion of the reaction, saturated sodium carbonate (Na2CO3) solution (5 mL) and dichloromethane (5 mL) were added, stirred at room temperature for 1 h, and the layers were separated. The aqueous layer was extracted with dichloromethane (3 x 5 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated to give H-Ala-OTAG9 as a pale yellow oil (quantitative yield, 19.1 mg).

[0159] Rf = 0.06 (hexanes / EtOAc = 5:1). [α] D 23 = -47.50 (c 0.40, CHCl3). 1 H NMR (400 MHz, CDCl3) δ 4.81 - 4.63 (m, 2H), 3.65 - 3.51 (m, 1H), 1.34 (d, J = 7.1 Hz, 3H), 0.23 - 0.16 (m, 27H). 13 C NMR (100 MHz, CDCl3) δ 175.8, 101.7, 86.4, 53.7, 50.0, 20.5, 0.2. IR (neat) 2949, 2894, 1745, 1677, 1398, 1316, 1244, 1172, 1137, 1042 cm -1 . HRMS (ESI) Calcd for C 15 H 35 NO2Si4Na [M+Na] + : 396.1643, Found: 396.1643.

[0160] III. Synthesis and Testing of TAG10 Synthesis of compound 24c (1,3-dibutyl-2-(butyldimethylsilyl)-1,1,3,3-tetramethyl-2-phenyltrisilane) [ka]

[0161] Tetrahydrofuran (20 mL) was added to a flame-dried flask containing lithium (granular, 222.1 mg, 32.0 mmol, 8.0 equiv) under nitrogen atmosphere at room temperature. Trichloro(phenyl)silane (0.641 mL, 4.0 mmol, 1.0 equiv) and butylchlorodimethylsilane (2.15 mL, 12.4 mmol, 3.1 equiv) were added together. The reaction was stirred at room temperature for 18 hours. The reaction mixture was then poured into a separatory funnel containing 50 mL of hexane and 50 mL of water. The layers were separated and the aqueous layer was extracted with hexane (3×50 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated. The residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 24c as a colorless oil (65% yield, 1.17 g).

[0162] Rf = 0.71 (100% hexanes). 1 H NMR (400 MHz, CDCl3) δ 7.48 - 7.39 (m, 2H), 7.25 - 7.19 (m, 3H), 1.37 - 1.19 (m, 12H), 0.89 - 0.80 (m, 9H), 0.74 - 0.60 (m, 6H), 0.23 - 0.11 (m, 18H). 13 C NMR (100 MHz, CDCl3) δ 136.7, 135.9, 127.5, 127.2, 26.6, 26.5, 17.0, 13.7, -0.9. IR (neat) 2955, 2921, 2871, 2857, 1463, 1427, 1243, 1078, 1024 cm -1 .

[0163] Synthesis of compound 24d (1,1,3,3-tetrabutyl-2-(dibutyl(methyl)silyl)-1,3-dimethyl-2-phenyltrisilane) [ka]

[0164] Tetrahydrofuran (60 mL) was added to a flame-dried flask containing a magnetic stir bar (Sm-Co) and dichloromethylsilane (1.23 mL, 12 mmol, 1.0 equiv) under nitrogen atmosphere at 0°C. n-BuMgCl (2.0 M in THF, 15 mL, 30 mmol, 2.5 equiv) was added dropwise. The resulting mixture was allowed to warm slowly to room temperature and stirred for 21 h. Upon completion, the reaction mixture was quenched with saturated ammonium chloride (NH4Cl) solution (60 mL) and the layers were separated. The aqueous layer was extracted with hexane (3 x 60 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated to give dibutyl(methyl)silane as a colorless oil (83% yield, 1.58 g).

[0165] To a flame dried flask containing a magnetic stir bar (Sm-Co) and dibutyl(methyl)silane (1.58 g, 9.95 mmol, 1.0 equiv) under nitrogen atmosphere at room temperature, dichloromethane (50 mL) was added followed by trichloroisocyanuric acid (786.3 mg, 3.38 mmol, 0.34 equiv). The resulting mixture was stirred for 3 h. Upon completion, the reaction mixture was concentrated and anhydrous hexane (20 mL) was added. The mixture was filtered through a pad of Celite and washed with hexane sw. The resulting organic layer was concentrated to give dibutylchloro(methyl)silane in 95% yield (1.83 g).

[0166] Tetrahydrofuran (15 mL) was added to a flame-dried flask containing lithium (granular, 170.0 mg, 24.5 mmol, 8.0 equiv) under nitrogen atmosphere at room temperature. Trichloro(phenyl)silane (0.491 mL, 3.1 mmol, 1.0 equiv) and dibutylchloro(methyl)silane (1.83 g, 9.5 mmol, 3.1 equiv) were added together. The reaction was stirred at room temperature for 6 days. The reaction mixture was then poured into a separatory funnel charged with 30 mL of hexane and 30 mL of water. The layers were separated and the aqueous layer was extracted with hexane (3×30 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated. The residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 24d as a colorless oil in 46% yield (818.7 mg).

[0167] 1 H NMR (400 MHz, CDCl3) δ 7.49 - 7.39 (m, 2H), 7.24 - 7.16 (m, 3H), 1.36 - 1.16 (m, 24H), 0.93 - 0.78 (m, 18H), 0.78 - 0.58 (m, 12H), 0.22 - 0.16 (m, 9H). 13 C NMR (100 MHz, CDCl3) δ 136.9, 136.5, 127.3, 127.0, 27.0, 26.8, 16.0, 13.7, -2.9. IR (neat) 2955, 2920, 2871, 2856, 1463, 1426, 1412, 1376, 1294, 1245, 1177 cm -1 .

[0168] Synthesis of compound 24e (1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyl-2-phenyltrisilane) [ka]

[0169] Tetrahydrofuran (20 mL) was added to a flame-dried flask containing lithium (granular, 222.1 mg, 32.0 mmol, 8.0 equiv) under nitrogen atmosphere at room temperature. Trichloro(phenyl)silane (0.641 mL, 4.0 mmol, 1.0 equiv) and decyldimethylchlorosilane (3.35 mL, 12.4 mmol, 3.1 equiv) were added together. The reaction was stirred at room temperature for 16 hours. The reaction mixture was poured into a separatory funnel containing 50 mL of hexane and 50 mL of water. The layers were separated and the aqueous layer was extracted with hexane (3×50 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated. The residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 24e as a colorless oil (74% yield, 2.07 g).

[0170] 1 H NMR (400 MHz, CDCl3) δ 7.47 - 7.38 (m, 2H), 7.25 - 7.18 (m, 3H), 1.34 - 1.20 (m, 48H), 0.92 - 0.84 (m, 9H), 0.74 - 0.58 (m, 6H), 0.25 - 0.11 (m, 18H). 13 C NMR (100 MHz, CDCl3) δ 136.7, 135.9, 127.5, 127.2, 33.8, 31.9, 29.7, 29.6, 29.4(2C), 24.3, 22.7, 17.4, 14.1, -0.8. IR (neat) 2955, 2920, 2852, 1465, 1427, 1244, 1087, 1027 cm -1 .

[0171] Synthesis of compound 24f (2-(dimethyl(octadecyl)silyl)-1,1,3,3-tetramethyl-1,3-dioctadecyl-2-phenyltrisilane) [ka]

[0172] Tetrahydrofuran (20 mL) was added to a flask containing lithium (granular, 222.1 mg, 32.0 mmol, 8.0 equiv) under nitrogen atmosphere at 0°C. Trichloro(phenyl)silane (0.641 mL, 4.0 mmol, 1.0 equiv) and chloro(dimethyl)octadecylsilane (4.30 g, 12.4 mmol, 3.1 equiv) were added together. The reaction was stirred at 0°C for 4 h and then at room temperature for 66 h. The reaction mixture was then poured into a separatory funnel containing 50 mL of hexane and 50 mL of water. The layers were separated and the aqueous layer was extracted with hexane (3 x 50 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated. The residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 24f as a white wax (59% yield, 2.44 g).

[0173] Mp 25-27 o C. 1 H NMR (400 MHz, CDCl3) δ 7.46 - 7.39 (m, 2H), 7.25 - 7.17 (m, 3H), 1.33 - 1.19 (m, 96H), 0.92 - 0.84 (m, 9H), 0.75 - 0.56 (m, 6H), 0.26 - 0.11 (m, 18H). 13 C NMR (100 MHz, CDCl3) δ 136.7, 135.9, 127.5, 127.2, 33.8, 31.9, 29.74(8C), 29.69, 29.6, 29.4(2C), 24.3, 22.7, 17.4, 14.1, -0.8. IR (neat) 2954, 2914, 2849, 1469, 1427, 1245, 1166 cm -1 .

[0174] Synthesis of compound 25a (2-ethynyl-1,1,1,3,3-hexamethyl-2-(trimethylsilyl)trisilane) [ka]

[0175] Tetrahydrofuran (3 mL) was added to a flask containing a magnetic stir bar (Sm-Co) and tris(trimethylsilyl)silyl chloride (141.6 mg, 0.5 mmol, 1.0 equiv) under nitrogen atmosphere at 0°C. Ethynylmagnesium chloride (0.5 M in THF, 1.5 mL, 0.75 mmol, 1.5 equiv) was added dropwise. The resulting mixture was stirred at room temperature for 20 hours. Upon completion, the reaction mixture was quenched with saturated ammonium chloride (NH4Cl) solution (10 mL) and the layers were separated. The aqueous layer was extracted with hexane (3 x 10 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated. The residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 25a as a colorless oil (55% yield, 75.4 mg).

[0176] Rf = 0.75 (100% hexanes). 1 H NMR (400 MHz, CDCl3) δ 2.30 (s, 1H), 0.22 (s, 27H). 13 C NMR (100 MHz, CDCl3) δ 95.8, 84.0, 0.2. IR (neat) 3299, 2950, ​​2894, 1398, 1244 cm -1 .

[0177] Synthesis of compound 25c (1,3-dibutyl-2-(butyldimethylsilyl)-2-ethynyl-1,1,3,3-tetramethyltrisilane) [ka]

[0178] To a flask containing a magnetic stir bar (Sm-Co) under nitrogen at 0° C., 24c (225.5 mg, 0.5 mmol, 1.0 equiv) and dichloromethane (2 mL) were added. Triflic acid (57.5 μL, 0.65 mmol, 1.3 equiv) was added. The reaction was stirred at room temperature for 1 h, then cooled to 0° C. and ethynylmagnesium chloride (0.5 M in THF, 2.0 mL, 1.0 mmol, 2.0 equiv) was added dropwise. After completion of the reaction, the reaction mixture was quenched with saturated ammonium chloride (NH4Cl) solution (10 mL) and the layers were separated. The aqueous layer was extracted with hexane (3×10 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated. The residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 25c as a colorless oil (yield 66%, 132.4 mg).

[0179] Rf = 0.82 (100% hexanes). 1 H NMR (400 MHz, CDCl3) δ 2.31 (s, 1H), 1.41 - 1.27 (m, 12H), 0.93 - 0.86 (m, 9H), 0.75 - 0.66 (m, 6H), 0.22 - 0.16 (m, 18H). 13 C NMR (100 MHz, CDCl3) δ 96.2, 84.7, 26.6(2C), 16.7, 13.8, -1.6. IR (neat) 3297, 2956, 2922, 2872, 1464, 1410, 1377, 1341, 1244, 1188, 1078, 1022 cm -1 . HRMS (ESI) Calcd for C 20 H 46 Si4Na [M+Na] + : 421.2574, Found: 421.2556.

[0180] Synthesis of compound 25e (1,3-didecyl-2-(decyldimethylsilyl)-2-ethynyl-1,1,3,3-tetramethyltrisilane) [ka]

[0181] At 0° C. under nitrogen atmosphere, dichloromethane (2 mL) was added to a flask containing a magnetic stir bar (Sm-Co) and 24e (351.7 mg, 0.5 mmol, 1.0 equiv). Triflic acid (57.5 μL, 0.65 mmol, 1.3 equiv) was added. The reaction was stirred at room temperature for 1 h, then cooled to 0° C. and ethynylmagnesium chloride (0.5 M in THF, 2.0 mL, 1.0 mmol, 2.0 equiv) was added dropwise. The resulting mixture was stirred at room temperature for 16 h. Upon completion, the reaction mixture was concentrated and the residue was purified by silica gel chromatography (eluent: 100% hexane) to give compound 25e as a colorless oil (89% yield, 289.1 mg).

[0182] Rf = 0.88 (100% hexanes). 1 H NMR (400 MHz, CDCl3) δ 2.30 (s, 1H), 1.40 - 1.20 (m, 48H), 0.92 - 0.84 (m, 9H), 0.74 - 0.65 (m, 6H), 0.25 - 0.12 (m, 18H). 13 C NMR (100 MHz, CDCl3) δ 96.2, 84.8, 33.8, 31.9, 29.70, 29.65, 29.42, 29.38, 24.5, 22.7, 17.1, 14.1, -1.6. IR (neat) 3297, 2955, 2920, 2852, 1465, 1244 cm -1 .

[0183] Synthesis of TAG10 (3-(1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyltrisilan-2-yl)prop-2-yn-1-ol) [ka]

[0184] Dichloromethane (4 mL) was added to a flame-dried flask containing a magnetic stir bar (Sm-Co) and 24e (703.5 mg, 1.0 mmol, 1.0 equiv) under nitrogen atmosphere at 0° C. Triflic acid (115.0 μL, 1.3 mmol, 1.3 equiv) was added. The reaction was stirred at room temperature for 1 h to give a 24e-OTF solution.

[0185] Tetrahydrofuran (10 mL) was added to another flame-dried flask containing a magnetic stir bar (Sm-Co) and compound 23 (252.3 mg, 1.8 mmol, 1.8 equiv) under nitrogen atmosphere at 78°C. n-Butylithium (1.55 M in hexanes, 1.16 mL, 1.8 mmol, 1.8 equiv) was added dropwise. The resulting mixture was stirred at -78°C for 1.5 hours. Then, the above 24e-OTF solution was slowly transferred to the reaction mixture. The reaction mixture was slowly warmed to room temperature and stirred for 4 hours. After completion, the reaction mixture was quenched with saturated aqueous ammonium chloride (NH4Cl) solution (10 mL) and the layers were separated. The aqueous layer was extracted with hexane (3 x 10 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated. The residue was used in the next step without further purification.

[0186] To a flame-dried flask containing a magnetic stir bar (Sm-Co) and the above residue at room temperature, methanol (5 mL) and tetrahydrofuran (5 mL) were added. p-Toluenesulfonic acid monohydrate (19.0 mg, 0.1 mmol, 0.1 equiv) was added. The reaction was stirred at room temperature for 4.5 h, and after completion of the reaction, the reaction mixture was concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc=50:1) to give HOTAG10 as a colorless oil in 59% overall yield (402.9 mg).

[0187] Rf = 0.32 (hexanes / EtOAc = 20:1). 1H NMR (400 MHz, CDCl3) δ 4.24 (d, J = 6.1 Hz, 2H), 1.37 - 1.24 (m, 48H), 0.92 - 0.84 (m, 9H), 0.73 - 0.64 (m, 6H), 0.21 - 0.12 (m, 18H). 13 C NMR (100 MHz, CDCl3) δ 107.0, 85.2, 52.3, 33.8, 31.9, 29.69, 29.65, 29.5, 29.4, 24.5, 22.7, 17.2, 14.1, -1.5. IR (neat) 2955, 2920, 2852, 1465, 1410, 1378, 1243, 1037 cm -1 . HRMS (ESI) Calcd for C 39 H 84 OSi4Na [M+Na] + : 703.5497, Found: 703.5546.

[0188] Esterification test 1: Synthesis of Boc-Ala-OTAG10 (3-(1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyltrisilan-2-yl)prop-2-yn-1-yl(tert-butoxycarbonyl)-L-alaninate) [ka]

[0189] To a flame-dried 15 mL vial containing a magnetic stir bar (Sm-Co) and HOTAG10 (136.3 mg, 0.2 mmol, 1.0 equiv) at 0° C. was added dichloromethane (1.0 mL). Boc-Ala-OH (75.7 mg, 0.4 mmol, 2.0 equiv) was added, followed by DMAP (29.3 mg, 0.24 mmol, 1.2 equiv) and DCC (82.5 mg, 0.4 mmol, 2.0 equiv). The reaction was stirred at room temperature for 16 h, then filtered, washed with dichloromethane (5 mL), and concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc=20:1) to give Boc-Ala-OTAG10 as a colorless oil (74% yield, 126.5 mg).

[0190] Rf = 0.69 (hexanes / EtOAc = 5:1). [α] D 23 = -34.94 (c 0.83, CHCl3). 1 1H NMR (400 MHz, CDCl3) δ 5.17 - 4.94 (m, 1H), 4.82 (d, J = 15.6 Hz, 1H), 4.62 (d, J = 15.5 Hz, 1H), 4.42 - 4.20 (m, 1H), 1.44 (s, 9H), 1.38 (d, J = 7.2 Hz, 3H), 1.36 - 1.19 (m, 48H), 0.96 - 0.78 (m, 9H), 0.75 - 0.59 (m, 6H), 0.26 - 0.08 (m, 18H). 13 13C NMR (100 MHz, CDCl3) δ 172.5, 155.0, 101.5, 87.6, 79.8, 54.1, 49.1, 33.8, 31.9, 29.69, 29.65, 29.42, 29.37, 28.3, 24.5, 22.7, 18.7, 17.1, 14.1, -1.5. IR (neat) 2956, 2922, 2853, 1750, 1721, 1498, 1455, 1366, 1339, 1308, 1244, 1160 cm -1 . HRMS (ESI) Calcd for C 47 H 97 NO4Si4Na [M+Na] + : 874.6392, Found: 874.6402.

[0191] Esterification test 2: Synthesis of Fmoc-Ala-OTAG10 (3-(1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyltrisilan-2-yl)prop-2-yn-1-yl(((9H-fluoren-9-yl)methoxy)carbonyl)-L-alaninate)

Chem.

[0192] To a flame-dried 15 mL vial containing a magnetic stir bar (Sm-Co) and HOTAG10 (136.3 mg, 0.2 mmol, 1.0 equiv) at 0° C. was added dichloromethane (1.0 mL). Fmoc-Ala-OH (124.5 mg, 0.4 mmol, 2.0 equiv) was added, followed by DMAP (29.3 mg, 0.24 mmol, 1.2 equiv) and DCC (82.5 mg, 0.4 mmol, 2.0 equiv). The reaction was stirred at room temperature for 16 h, then filtered, washed with dichloromethane (5 mL), and concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc=20:1→15:1) to give Fmoc-Ala-OTAG10 as a pale yellow oil (79% yield, 153.4 mg).

[0193] Rf = 0.60 (hexanes / EtOAc = 5:1). [α] D 23 = -27.35 (c 1.28, CHCl3). 1 H NMR (400 MHz, CDCl3) δ 7.77 (d, J = 7.5 Hz, 2H), 7.65 - 7.57 (m, 2H), 7.45 - 7.37 (m, 2H), 7.37 - 7.27 (m, 2H), 5.37 (d, J = 7.8 Hz, 1H), 4.85 (d, J = 15.6 Hz, 1H), 4.66 (d, J = 15.5 Hz, 1H), 4.49 - 4.36 (m, 3H), 4.23 (t, J = 7.0 Hz, 1H), 1.45 (d, J = 7.2 Hz, 3H), 1.37 - 1.18 (m, 48H), 0.93 - 0.84 (m, 9H), 0.73 - 0.64 (m, 6H), 0.26 - 0.11 (m, 18H). 13C NMR (100 MHz, CDCl3) δ 172.2, 155.5, 143.9, 143.8, 141.3, 127.7, 127.0, 125.1, 120.0, 101.4, 88.0, 67.0, 54.3, 49.6, 47.2, 33.8, 31.9, 29.69, 29.66, 29.42, 29.37, 24.5, 22.7, 18.7, 17.1, 14.1, -1.5. IR (neat) 2921, 2852, 1726, 1506, 1450, 1379, 1335, 1306, 1243, 1195, 1167 cm -1 . HRMS (ESI) Calcd for C 57 H 99 NO4Si4Na [M+Na] + : 996.6549, Found: 996.6551.

[0194] · Tolerance test 1: Synthesis of H-Ala-OTAG10 (3-(1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyltrisilan-2-yl)prop-2-yn-1-yl L-alaninate) [ka]

[0195] To a 6 mL flame-dried vial containing a magnetic stir bar (Sm-Co) and Boc-Ala-OTAG10 (77.8 mg, 0.091 mmol, 1.0 equiv) at room temperature was added dichloromethane (0.090 mL). Hydrochloric acid solution (4.0 M in dioxane, 0.228 mL, 0.91 mmol, 10.0 equiv) was added. The reaction was stirred at room temperature for 2 h. Upon completion, saturated sodium carbonate (Na2CO3) solution (5 mL) and dichloromethane (5 mL) were added and the layers were separated. The aqueous layer was extracted with dichloromethane (3 x 5 mL). The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated to give H-Ala-OTAG10 as a colorless oil (quantitative yield, 69.8 mg).

[0196] Rf = 0.23 (hexanes / EtOAc = 5:1). [α] D24 = -18.75 (c 1.28, CHCl3). 1 1H NMR (400 MHz, CDCl3) δ 4.80 (d, J = 15.6 Hz, 1H), 4.65 (d, J = 15.6 Hz, 1H), 3.88 - 3.71 (m, 1H), 1.47 (d, J = 6.9 Hz, 3H), 1.37 - 1.23 (m, 48H), 0.94 - 0.83 (m, 9H), 0.71 - 0.62 (m, 6H), 0.16 (s, 18H). 13 13C NMR (100 MHz, CDCl3) δ 173.7, 101.4, 87.9, 54.3, 49.6, 33.7, 31.9, 29.7, 29.6, 29.41, 29.36, 24.5, 22.7, 19.0, 17.1, 14.1, -1.6. IR (neat) 2922, 2853, 1744, 1459, 1244, 1171, 1037 cm -1 . HRMS (ESI) Calcd for C 42 H 89 NO2Si4Na [M+Na] + : 774.5868, Found: 774.5915.

[0197] · Tolerance test 2: Synthesis of H-Ala-OTAG10 (3-(1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyltrisilan-2-yl)propion-2-yn-1-yl L-alaninate)

Chem.

[0198] To a 6 mL flame-dried vial containing a magnetic stir bar (Sm-Co) and Fmoc-Ala-OTAG10 (107.0 mg, 0.11 mmol, 1.0 equiv) at room temperature, dichloromethane (1.1 mL) was added. DBU (0.0328 mL, 0.22 mmol, 2.0 equiv) was added. The reaction was stirred at room temperature for 0.5 h. Upon completion, the reaction mixture was concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc = 20:1 to 4:1) to give H-Ala-OTAG10 as a colorless oil (yield 87%, 71.6 mg).

[0199] IV. Synthesis of Protected Nelipepimut-S via Boc Chemistry Using TAG10 First esterification step: Synthesis of Boc-Leu-OTAG10 (3-(1,3-didecyl-2-(decyldimethylsilyl)-1,1,3,3-tetramethyltrisilan-2-yl)prop-2-yn-1-yl(tert-butoxycarbonyl)-L-leucinate) [ka]

[0200] To a flame-dried flask containing a magnetic stir bar (Sm-Co) and HOTAG10 (1.11 g, 1.63 mmol, 1.0 equiv) at room temperature was added dichloromethane (8.0 mL). Boc-Leu-OH (753.7 mg, 3.26 mmol, 2.0 equiv) was added, followed by DMAP (238.9 mg, 1.96 mmol, 1.2 equiv) and DCC (672.4 mg, 3.26 mmol, 2.0 equiv). The reaction was stirred at room temperature for 3 h, then filtered, washed with dichloromethane (5 mL), and concentrated. The residue was purified by silica gel chromatography (eluent: hexane / EtOAc = 33:1) to give Boc-Leu-OTAG10 as a colorless oil (95% yield, 1.38 g).

[0201] Rf = 0.29 (hexanes / EtOAc = 20:1). [α] D 24 = -33.01 (c 1.03, CHCl3). 11H NMR (400 MHz, CDCl3) δ 4.93 - 4.76 (m, 2H), 4.59 (d, J = 15.5 Hz, 1H), 4.44 - 4.27 (m, 1H), 1.81 - 1.66 (m, 1H), 1.64 - 1.58 (m, 1H), 1.54 - 1.40 (m, 10H), 1.36 - 1.17 (m, 48H), 0.98 - 0.92 (m, 6H), 0.92 - 0.84 (m, 9H), 0.71 - 0.63 (m, 6H), 0.22 - 0.12 (m, 18H). 13 13C NMR (100 MHz, CDCl3) δ 172.6, 155.3, 101.6, 87.4, 79.8, 53.9, 52.0, 42.0, 33.8, 31.9, 29.69, 29.66, 29.43, 29.37, 28.3, 24.8, 24.5, 22.8, 22.7, 21.9, 17.1, 14.1, -1.5. IR (neat) 2956, 2921, 2853, 1750, 1721, 1500, 1466, 1367, 1333, 1244, 1158, 1121 cm -1 . HRMS (ESI) Calcd for C 50 H 103 NO4Si4Na [M+Na] + : 916.6862, Found: 916.6907.

[0202] General procedure for Boc deprotection and coupling reactions

Chem.

[0203] To a flame dried flask charged with a magnetic stir bar (Sm-Co) and Boc protected peptide (1.0 equiv) at room temperature was added dichloromethane (1.0 M). Hydrochloric acid solution (4.0 M in dioxane, 10.0-15.0 equiv) was added. The reaction was stirred at room temperature for 1-2 hours (monitored by TLC). After completion, saturated sodium carbonate (Na2CO3) solution and dichloromethane were added and the layers were separated. The aqueous layer was extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated. The resulting residue was utilized in the next Boc-coupling step without further purification.

[0204] To a flame dried flask containing a magnetic stir bar (Sm-Co) and the above residue was added dichloromethane (0.05-0.2M) at room temperature. Boc-protected amino acid (Boc-AA-OH, 1.1-1.2 equiv) was added followed by EDC-HCl (1.2 equiv) and HOBt (0.3 equiv). The resulting mixture was stirred at room temperature. Upon completion, the mixture was diluted with dichloromethane and saturated aqueous sodium carbonate (Na2CO3) was added. The layers were separated and the aqueous layer was extracted three times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated. The resulting residue was used in the next Boc-deprotection step without further purification.

[0205] Elongation: Synthesis of Boc-Lys(Boc)-Ile-Phe-Gly-Ser(Bn)-Leu-Ala-Phe-Leu-OTAG10 (compound 27) [ka]

[0206] Dichloromethane (0.15 mL) was added to a flame-dried flask containing a magnetic stir bar (Sm-Co) and the Boc-protected peptide Boc-Leu-OTAG10 (134.2 mg, 0.15 mmol, 1.0 equiv) at room temperature. The general procedure of Boc deprotection and coupling reaction was then repeated seven more times (total 8 times) while sequentially changing the coupling amino acid according to the sequence of the target peptide. In the last coupling step, after the reaction was completed, the work-up procedure was completed and the residue was purified by silica gel chromatography (eluent: DCM / MeOH=10:1) to give compound 27 as a white solid (total yield 62%, 181.2 mg). Rf = 0.42 (DCM / MeOH = 10:1). HRMS (ESI) Calcd for C 106 H 182 N 10 O 15 Si4Na [M+Na] + : 1970.2761, Found: 1970.2796.

[0207] Cleavage: Synthesis of Boc-Lys(Boc)-Ile-Phe-Gly-Ser(Bn)-Leu-Ala-Phe-Leu-OH (compound 28) [ka]

[0208] To a 6 mL flame dried vial containing a magnetic stir bar (Sm-Co) and compound 27 (39.0 mg, 0.02 mmol, 1.0 equiv) at room temperature was added chloroform (0.2 mL), methanol (60 μL), and water (20 μL). Lithium hydroxide monohydrate (2.1 mg, 0.05 mmol, 2.5 equiv) was added. The reaction was stirred at room temperature for 24 hours. Upon completion, the reaction mixture was concentrated. Dichloromethane (1.0 mL) was added followed by hydrochloric acid solution (2N in water, 60 μL, 0.12 mmol, 6.0 equiv). An additional 0.5 mL of water was added and the layers were separated. The organic layer was concentrated and washed with hexane (3×1 mL). The remaining white solid was obtained as compound 28 (93% yield, 23.9 mg). The purity of the product was 83% as determined by RP-HPLC using a modified phase column (ODS-HL, 4.6 mm×25 cm). HRMS (ESI) Calcd for C 67 H 100 N 10 O 15 Na [M+Na] + : 1307.7267, Found: 1307.7280.

Claims

1. A method for producing a polypeptide compound, comprising: subjecting a carboxyl group on the right side of an amino acid or peptide compound represented by the following formula (R1) to an amide-forming reaction with an amino group on the left side of an amino acid ester or peptide ester compound represented by the following formula (R2), thereby obtaining a peptide compound represented by the following formula (P1): 【Chemistry 1】 In formula (R1), T a represents a hydrogen atom or a monovalent substituent, R 11 and R 12 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, or a thiol group, or an amino group, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent heterocyclic group, each of which may have one or more substituents; R 13 represents a hydrogen atom, a carboxyl group, a hydroxyl group, or a monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group which may have one or more substituents, in which case the monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group may be bonded to a nitrogen atom via a linking group, Or, R 11 and R 13 and are bonded to each other to form R 11 and the carbon atom to which R 13 may form, together with the nitrogen atom to which it is bonded, a heterocycle which may have one or more substituents, A 11 and A 12 each independently represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have one or more substituents, p11 and p12 each independently represent 0 or 1; n 1 is an integer of 1 or more and represents the number of constitutional units represented by the structure in [ ]. 1 When the number is 2 or more, the multiple constitutional units represented by the structure in [ ] may be the same or different. 【Chemistry 2】 In formula (R2), T b represents a hydrogen atom or a monovalent substituent, R 21 and R 22 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, or a thiol group, or an amino group, a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, or a monovalent heterocyclic group, each of which may have one or more substituents; R 23 represents a hydrogen atom, a carboxyl group, a hydroxyl group, or a monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group which may have one or more substituents, in which case the monovalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group may be bonded to a nitrogen atom via a linking group, Or, R 21 and R 23 and are bonded to each other to form R 21 and the carbon atom to which R 23 may form, together with the nitrogen atom to which it is bonded, a heterocycle which may have one or more substituents, A 21 and A 22 each independently represents a divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have one or more substituents, p21 and p22 each independently represent 0 or 1; n 2 is an integer of 1 or more and represents the number of constitutional units represented by the structure in [ ]. 2 When the number is 2 or more, the multiple constitutional units represented by the structure in [ ] may be the same or different. however, (i) T a is a group represented by -O-C(=O)-TAG(Si), and / or (ii) T b is a group represented by -TAG(Si). Here, -TAG(Si) is a group having the following structure: 【Chemistry 3】 In formula (T), R x represents a divalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heterocyclic group, which may have one or more substituents, R z1 ~R z9 each independently represents a monovalent aliphatic hydrocarbon group, an aromatic hydrocarbon group, a silicon-containing hydrocarbon group, or a heterocyclic group, which may have one or more substituents, provided that R z1 ~R z9 At least three of the above are aliphatic hydrocarbon groups having 7 or more carbon atoms which may have one or more substituents. 【Chemistry 4】 In formula (P1), T a , R 11 , R 12 , R 13 , A 11 , A 12 , p11, p12, and n 1 represents the same group as defined in formula (R1), R 21 , R 22 , R 23 , A 21 , A 22 , p21, p22, n 2 , and T b represents the same group as defined in formula (R2).

2. In formula (T), R x The method according to claim 1 , wherein is a divalent aliphatic hydrocarbon having two or more carbon atoms.

3. 3. The process according to claim 1 or 2, wherein the reaction is carried out in an organic solvent.

4. The process according to any one of claims 1 to 3, wherein the reaction is carried out in the presence of a Lewis acid catalyst.

5. The method according to claim 4, wherein the Lewis acid catalyst is a metal compound containing one or more metals selected from the group consisting of aluminum, titanium, zirconium, hafnium, tantalum, and niobium.

6. The method according to any one of claims 1 to 5, wherein the reaction is carried out in the presence of a phosphorus compound.

7. The method according to claim 6 , wherein the phosphorus compound is a phosphine compound or a phosphate compound.

8. The method according to any one of claims 1 to 7, wherein the reaction is carried out in the presence of a silane compound.

9. T in the formula (R1) a The method according to any one of claims 1 to 8, further comprising the step of removing the -O-C(=O)-TAG(Si) group of the peptide compound of formula (P1) after synthesis thereof to deprotect the terminal amino group of the peptide compound.

10. T in the formula (R2) b The method according to any one of claims 1 to 9, further comprising the step of removing the -TAG(Si) group of the peptide compound of formula (P1) after synthesis thereof to deprotect the terminal carboxyl group of the peptide compound.

11. The method according to any one of claims 1 to 10, wherein the reaction is a batch reaction or a flow reaction.

12. An amino acid or peptide compound represented by the following formula (R1'): 【Chemistry 5】 In formula (R1'), R 11 , R 12 , R 13 , A 11 , A 12 , p11, p12, n 1 The definitions of each of the groups of the same reference numerals in claim 1 are the same as those in claim 1.

13. An amino acid ester or peptide ester compound represented by the following formula (R2'): 【Chemistry 6】 In formula (R2'), R 21 , R 22 , R 23 , A 21 , A 22 , p21, p22, n 2 The definitions of each of the groups of the same reference numerals in claim 1 are the same as those in claim 1.

14. A peptide compound represented by the following formula (P1'): 【Chemistry 7】 In formula (P1'), R 11 , R 12 , R 13 , R 21 , R 22 , R 23 , A 11 , A 12 , A 21 , A 22 , p21, p22, p11, p12, n 1 , n 2 , T a , and T b has the same definition as the radical of the same symbol in claim 1. however, (i) T a is a group represented by -O-C(=O)-TAG(Si), and / or (ii) T b is a group represented by -TAG(Si). The definition of TAG(Si) is the same as that of the group having the same reference symbol in claim 1.

15. A compound represented by the following formula (C0): 【Chemistry 8】 In formula (C0), the definition of TAG(Si) is the same as the definition of the group of the same symbol in claim 1. be.

16. A compound represented by the following formula (C1): 【Chemistry 9】 In formula (C1), the definition of TAG(Si) is the same as the definition of the group of the same symbol in claim 1, R C1 is any monovalent group.

17. A compound represented by the following formula (C2): 【Chemistry 10】 In formula (C2), the definition of TAG(Si) is the same as the definition of the group of the same symbol in claim 1; R C21 and R C22 are each independently any monovalent group.

18. In formula (T), R x The compound according to any one of claims 15 to 17, wherein is a divalent aliphatic hydrocarbon having two or more carbon atoms.

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