Method for producing peptide compounds using free-standing condensing agents

Abstract

Provided is a method for producing a peptide compound or a salt thereof, the method comprising a step in which an amino group of a first amino acid or a peptide and a carboxyl group of a second amino acid or a peptide are linked by an amide bond (linking step), in which a free-standing condensing agent and at least one additive are used, and the additive is at least one selected from the group consisting of HOPO, HOAt, HOOBt, HOCt, PfpOH, Oxyma, Oxyma-B, N-HOSu, and K-Oxyma.

Description

Technical Field

[0001] This invention relates to a method for producing peptide compounds using independent condensing agents. Background Technology

[0002] Recently, it has been found that the metabolic stability and membrane permeability of peptides are improved by using non-natural amino acids such as cyclic peptides (Non-Patent Literature 1 and 2). In particular, cyclic peptide compounds containing N-substituted amino acids have been proposed to have drug-like properties such as metabolic stability and membrane permeability, and can be used for the generation of inhibitors of protein-protein interactions (Patent Literature 1, Non-Patent Literature 3).

[0003] Since peptide compounds have attracted attention as pharmaceuticals, methods for producing peptide compounds have also been considered important (Non-Patent Document 4). Peptide compounds are typically synthesized by elongating the peptide chain (by repeatedly linking the C-terminal carboxyl group of an amino acid to another amino acid or the N-terminal amino group of a peptide). Known examples of methods for elongating peptide chains include methods using HOPO (2-hydroxypyridine-N-oxide) as an additive (Non-Patent Document 5), methods using Oxyma (ethyl 2-cyano-2-(hydroxyimino)acetate) (Non-Patent Document 6), and methods using both HOPO and Oxyma as additives and carbodiimide as a condensing agent (Patent Document 2). Methods using TPTU as a condensing agent and HOBt as an additive are also known (Non-Patent Document 7).

[0004] Another known method for extending peptide chains is called fragment coupling, which involves subjecting peptide fragments, each composed of multiple amino acid residues, to an amide bond formation reaction that links them together. Fragment coupling offers the advantage of high overall yield of the final product. The more amino acid residues in the desired peptide compound, the greater the advantage. However, under conventional amide bond formation conditions, the increase in impurities due to racemization at the α-position of amino acid residues and the resulting decrease in the yield and purity of the target product significantly increases the difficulty of purification, leading to increased time and effort involved in production. Furthermore, when the N-terminus or C-terminus is an N-substituted amino acid and it becomes the reaction site for the amide bond formation reaction in fragment coupling, reduced reactivity becomes a problem (Non-Patent Literature 8). Therefore, when synthesizing peptide compounds containing N-substituted amino acids, synthetic methods have been limited to methods that subject amino acids to amide bond formation reactions sequentially, one residue at a time, or fragment coupling methods using residues that do not cause epimerization.

[0005] Citation List

[0006] Patent documents

[0007] Patent Document 1, International Publication No. WO 2013 / 100132

[0008] Patent Document 2 International Publication No. WO 2023 / 117904

[0009] Non-patent literature

[0010] Non-patent literature 1 Acc. Chem. Res. 2008, 41, 1331-1342.

[0011] Non-patent literature 2 Angew. Chem. Int. Ed., 2013, 52, 254-269.

[0012] Non-patent literature 3 Chem. Rev., 2019, 119, 10360-10391.

[0013] Non-patent document 4 Amino Acids, Peptides and Proteins in Organic Chemistry: Building Blocks, Catalysis and Coupling Chemistry, Volume 3, 2011.

[0014] Non-patent literature 5 Tetrahedron Letters., 2020, 152299.

[0015] Non-patent literature 6 Tetrahedron Letters., 2021, 153462.

[0016] Non-patent literature 7 Tetrahedron Letters., 1989, 11927.

[0017] Non-patent literature 8 J. Peptide Res., 2005, 65, 153-166. Summary of the Invention

[0018] Technical issues

[0019] The present invention was made in view of these circumstances. In one aspect, the problem to be solved is to establish a novel synthetic method for peptide compounds. In one aspect, the problem to be solved is to establish a novel synthetic method suitable for fragment coupling of peptide compounds. In one aspect, the problem to be solved is to establish a synthetic method in which all amino acid residues constituting the peptide compound maintain high diastereoselectivity even through fragment coupling. In one aspect, the problem to be solved is to establish a method for synthesizing peptide compounds with high diastereoselectivity and high yield even through fragment coupling. In one aspect, the problem to be solved is to establish a method for synthesizing peptide compounds in high yield through fragment coupling while preventing racemization at the α-carbon of the carboxyl group of the reaction substrate. In one aspect, the problem to be solved is to establish a synthetic method suitable for fragment coupling of peptide compounds containing N-substituted amino acids at the N-terminus or C-terminus. In one aspect, the problem to be solved is to establish a synthetic method suitable for fragment-coupled peptide compounds in which the nitrogen atom of the α-carbon bound to the carboxyl group of the reaction substrate is substituted with an alkyl group.

[0020] Solution to the problem

[0021] The inventors have conducted in-depth research to solve the above-mentioned problems. Therefore, the inventors have discovered a method for solving at least one of the above problems by carrying out an amide bond formation reaction in a reaction system in the presence of a separate condensing agent and one or more additives. Furthermore, the inventors have discovered reaction conditions that can suppress the generation of byproducts in the condensation reaction.

[0022] In one specific non-limiting aspect, the invention covers the following.

[0023] [1] A method for producing a peptide compound or a salt thereof, the method comprising the step of linking the amino group of a first amino acid or peptide to the carboxyl group of a second amino acid or peptide by an amide bond (the linking step), wherein a separate condensing agent and one or more additives are used in the linking step, and the additive is selected from 2-hydroxypyridine-N-oxide (HOPO), 1-hydroxy-7-azabenzotriazole (HOAt), 3,4-dihydro-3-hydroxy-4-oxo-benzotriazine (HOOBt), ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt), 2,2,3,3,3-pentafluoro-1-propanol (PfpOH), ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma), 5-(hydroxyimino)-1,3-dimethylpyrimidin-2,4,6-(1H,3H,5H)-trione (Oxyma-B), and N-hydroxysuccinimide (HOSu). One or more of the group consisting of potassium salt of (hydroxyimino)cyanoethyl acetate (K-Oxyma).

[0024] [1-1] The method according to [1], wherein the additive is one or more selected from the group consisting of HOPO, HOAt, HOOBt, HOCt, Oxyma, Oxyma-B and HOSu.

[0025] [1-2] The method according to [1-1], wherein the additive is selected from the group consisting of HOPO, HOAt, HOOBt, HOCt, Oxyma, Oxyma-B and HOSu.

[0026] [2] According to the method of [1], wherein the independent condensing agent has a structure in the molecule represented by any of the following formulas (1) to (4):

[0027] [Formula 1]

[0028]

[0029] [Equation 2]

[0030]

[0031] [Formula 3]

[0032]

[0033] Where R 4 For CH or N,

[0034] [Formula 4]

[0035] .

[0036] [2-2] According to the method of [1] or [2], wherein the independent condensing agent has a structure in the molecule represented by any of the following formulas (5) to (7):

[0037] [Formula 5]

[0038]

[0039] [Formula 6]

[0040]

[0041] [Formula 7]

[0042] .

[0043] [3] According to the method of [1], wherein the independent condensing agent is selected from 2-cyano-2-((dimethylimino)(morpholinyl)methyloxime)ethyl acetate hexafluorophosphate (COMU), 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), O-[(ethoxycarbonyl)cyanomethyleneamino]-N,N,N',N'-tetramethylureonium hexafluorophosphate (HOTU), O- At least one of the following groups: (3,4-dihydro-4-oxo-1,2,3-benzotriazine-3-yl)-N,N,N',N'-tetramethylureon tetrafluoroborate (TDBTU), 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazine-4(3H)-one (DEPBT), O-[2-oxo-1(2H)-pyridyl]-N,N,N',N'-tetramethylureon tetrafluoroborate (TPTU), 2-bromo-1-ethylpyridinium tetrafluoroborate (BEP), and salicylamino-2-benzylthiophenol (Ph2CP).

[0044] [4] The method according to [3], wherein the independent condensing agent is at least one selected from the group consisting of COMU, HATU, HOTU, DEPBT, TPTU and TDBTU.

[0045] [4-1] According to the method of [4], wherein the independent condensing agent is at least one selected from the group consisting of COMU, HATU, HOTU, DEPBT and TDBTU.

[0046] [5] The method according to any one of [1] to [4], wherein the independent condensing agent is used in a molar equivalent of 0.5 to 5.0 relative to the first amino acid or peptide.

[0047] [6] The method according to any one of [1] to [5], wherein the independent condensing agent is at least one selected from the group consisting of COMU, HATU, HOTU, DEPBT and TDBTU, and the additive is HOPO.

[0048] [7] The method according to any one of [1] to [6], wherein one or more additives are used in a molar equivalent of 0.1 to 5.0 relative to the first amino acid or peptide.

[0049] [8] The method according to any one of [1] to [7], wherein the second amino acid or peptide is a peptide containing two or more amino acid residues.

[0050] [9] According to any one of [1] to [8], the amino group containing the nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is of the formula: -NR 5 - indicates that R 5 It can be a hydrogen atom, a straight-chain C1-C6 alkyl group, a branched C3-C6 alkyl group, or a C3-C8 cycloalkyl group.

[0051]

[10] According to any one of [1] to [9], the amino group containing the nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is of the formula: -NR 5 - indicates that R 5 It consists of hydrogen atoms or straight-chain C1-C4 alkyl groups.

[0052] [10-1] The method according to any one of [1] to

[10] , wherein the amino group containing the nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is of the formula: -NR 5 - indicates that R 5 It can be a hydrogen atom, a methyl group, or an ethyl group.

[0053]

[11] According to any one of [1] to [10-1], the amino group containing the nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is of the formula: -NR 5 - indicates that R 5 It can be a hydrogen atom or a methyl group.

[0054]

[12] The method according to any one of [1] to

[11] , wherein the first amino acid or peptide is a peptide containing two or more amino acid residues.

[0055]

[13] The method according to any one of [1] to

[12] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom, a straight-chain C1-C6 alkyl group, a branched C3-C6 alkyl group, or a C3-C8 cycloalkyl group.

[0056]

[14] The method according to any one of [1] to

[13] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 - represents an amino group, where R 6 It is a hydrogen atom, and R 7 It consists of hydrogen atoms or straight-chain C1-C4 alkyl groups.

[0057]

[15] The method according to any one of [1] to

[14] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom, a methyl group, or an ethyl group.

[0058]

[16] The method according to any one of [1] to

[15] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 - represents an amino group, where R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom or a methyl group.

[0059]

[17] The method according to any one of [1] to

[16] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It is a methyl group.

[0060]

[18] The method according to any one of [1] to

[17] , wherein the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 and R 9 The same or different and each being a hydrogen atom, optionally substituted straight-chain C1-C4 alkyl, optionally substituted branched C3-C6 alkyl, optionally substituted C1-C4 alkoxy-C1-C2 alkyl, straight-chain C2-C6 alkenyl, optionally substituted phenyl C1-C2 alkyl or optionally substituted 5- to 6-membered heteroaryl C1-C2 alkyl.

[0061]

[19] The method according to any one of [1] to

[18] , wherein the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 and R 9 They may be the same or different and each is a hydrogen atom, a straight-chain C1-C3 alkyl group, an isopropyl group, a 1-methylpropyl group, a 2-methylpropyl group, a tert-butoxymethyl group, a 2-propenyl group, or an optionally substituted benzyl group.

[0062]

[20] The method according to any one of [1] to

[19] , wherein the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 It is a hydrogen atom, and R 9 It can be a hydrogen atom, methyl, 1-methylpropyl, 2-methylpropyl, tert-butoxymethyl, 2-propenyl, benzyl, p-methylbenzyl, or p-fluorobenzyl.

[0063]

[21] The method according to any one of [1] to

[20] , wherein the carboxyl group of the first amino acid or peptide is protected.

[0064]

[22] The method according to any one of [1] to

[21] , wherein the amino group of the second amino acid or peptide is protected.

[0065]

[23] The method according to any one of [1] to

[22] , wherein an alkali is used in the connection step.

[0066]

[24] According to the method of

[23] , the pKa of the conjugate acid of the base used in the connection step is between 0 and 15.0, more preferably between 3 and 13.0, and even more preferably between 5 and 11.5.

[0067] [24-1] The method according to

[24] , wherein the pKa is a measurement of the pKa when water at 25°C is used as the solvent.

[0068]

[25] According to the method of

[23] or

[24] , wherein the base used in the connection step is an organic base.

[0069]

[26] The method according to any one of

[23] to

[25] , wherein the base used in the connecting step is at least one selected from the group consisting of dicyclohexylmethylamine, diisopropylethylamine, triethylamine, N-methylmorpholine, 4-N,N-dimethylaminopyridine, 2,6-dimethylpyridine and 2,4,6-trimethylpyridine.

[0070] [26-1] The method according to any one of

[23] to

[26] , wherein the base used in the connecting step is dicyclohexylmethylamine or diisopropylethylamine.

[0071]

[27] The method according to any one of [1] to

[26] , wherein the connection step is performed by liquid-phase synthesis.

[0072]

[28] The method according to

[27] wherein the liquid-phase synthesis is carried out in an organic solvent.

[0073]

[29] According to the method of

[28] , wherein the organic solvent used in the connecting step is at least one selected from the group consisting of acetonitrile, isopropyl acetate, ethyl acetate, butyl acetate, methyl tert-butyl ether, diethyl ether, dichloromethane, tetrahydrofuran, 2-methyltetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide and toluene or a mixture thereof.

[0074]

[30] According to the method of

[29] , the organic solvent used in the connecting step is at least one selected from the group consisting of acetonitrile, isopropyl acetate, methyl tert-butyl ether, dichloromethane, 2-methyltetrahydrofuran, N,N-dimethylformamide and toluene or a mixture thereof.

[0075] [30-1] According to the method of

[30] , the organic solvent used in the connecting step is at least one selected from the group consisting of acetonitrile, isopropyl acetate and 2-methyltetrahydrofuran or a mixture thereof.

[0076]

[31] The method according to any one of [1] to

[30] further includes a deprotection step.

[0077]

[32] The method according to any one of [1] to

[31] , wherein the connection step is repeated two or more times.

[0078]

[33] The method according to any one of [1] to

[32] , wherein the peptide compound or its salt produced contains 8 to 20 amino acid residues.

[0079]

[34] The method according to any one of [1] to

[33] wherein the peptide compound or its salt produced contains 11 to 14 amino acid residues.

[0080]

[35] The method according to any one of [1] to

[34] , wherein the peptide compound produced contains at least one non-natural amino acid residue.

[0081]

[36] The method according to any one of [1] to

[35] wherein the peptide compound produced contains at least four non-natural amino acid residues.

[0082]

[37] The method according to any one of [1] to

[36] , wherein the peptide compound produced contains at least five non-natural amino acid residues.

[0083]

[38] The method according to any one of

[35] to

[37] , wherein the non-natural amino acid is an N-methyl amino acid residue.

[0084]

[39] The method according to any one of [1] to

[38] , wherein the peptide compound or salt thereof produced contains a cyclic portion consisting of four or more amino acid residues, and wherein the cyclic portion contains amide bonds at positions 1 to 7 for linking the amino group of the first amino acid or peptide to the carboxyl group of the second amino acid or peptide.

[0085]

[40] The method according to any one of [1] to

[39] is carried out using a flow reaction apparatus.

[0086]

[41] A peptide compound or a salt thereof, produced by the method according to any one of [1] to

[40] .

[0087]

[42] A pharmaceutical composition comprising a peptide compound or a salt thereof produced by the method according to any one of [1] to

[40] .

[0088]

[43] A linker comprising a separate condensing agent and one or more additives for linking the amino group of a first amino acid or peptide to the carboxyl group of a second amino acid or peptide by an amide bond.

[0089]

[44] According to the linker described in

[43] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It is a hydrogen atom, a straight-chain C1-C6 alkyl group, a branched C3-C6 alkyl group, or a C3-C8 cycloalkyl group, and the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 and R 9 The same or different and each being a hydrogen atom, optionally substituted straight-chain C1-C4 alkyl, optionally substituted branched C3-C6 alkyl, optionally substituted C1-C4 alkoxy-C1-C2 alkyl, straight-chain C2-C6 alkenyl, optionally substituted phenyl C1-C2 alkyl or optionally substituted 5- to 6-membered heteroaryl C1-C2 alkyl.

[0090]

[45] According to the linker of

[44] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R7 - represents an amino group, where R 6 It is a hydrogen atom, and R 7 It consists of hydrogen atoms or straight-chain C1-C4 alkyl groups.

[0091]

[46] The linker according to any one of

[44] to

[45] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom, a methyl group, or an ethyl group.

[0092]

[47] The linker according to any one of

[44] to

[46] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 - represents an amino group, where R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom or a methyl group.

[0093]

[48] ​​The linker according to any one of

[44] to

[47] , wherein the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It is a methyl group.

[0094]

[49] The linker according to any one of

[44] to

[48] , wherein the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 and R 9 They may be the same or different and each is a hydrogen atom, a straight-chain C1-C3 alkyl group, an isopropyl group, a 1-methylpropyl group, a 2-methylpropyl group, a tert-butoxymethyl group, a 2-propenyl group, or an optionally substituted benzyl group.

[0095]

[50] The linker according to any one of

[44] to

[49] , wherein the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 It is a hydrogen atom, and R 9 It can be a hydrogen atom, methyl, 1-methylpropyl, 2-methylpropyl, tert-butoxymethyl, 2-propenyl, benzyl, p-methylbenzyl, or p-fluorobenzyl.

[0096] In the above numbering, unless otherwise stated, the number referenced in a dependent entry includes the branch number of that number. For example, the reference [1] in a dependent entry indicates that it includes not only [1] but also its branch number [1-1]. The same applies to other numbering.

[0097] Beneficial effects of the invention

[0098] According to the present invention, peptide compounds can be synthesized with high diastereoselectivity and high yield even through fragment coupling. Detailed Implementation

[0099] The abbreviations used in this article are listed below.

[0100] 2-MeTHF: 2-Methyltetrahydrofuran

[0101] IPAC: Isopropyl acetate

[0102] EtOAc: Ethyl acetate

[0103] MeCN: Acetonitrile

[0104] THF: Tetrahydrofuran

[0105] MeOH: Methanol

[0106] MTBE: Methyl tert-butyl ether

[0107] CPME: Cyclopentylmethyl ether

[0108] DCM: Dichloromethane

[0109] DMF: N,N-Dimethylformamide

[0110] DMA: N,N-dimethylacetamide

[0111] NMP: N-methylpyrrolidone

[0112] DMSO: Dimethyl sulfoxide

[0113] DIPEA: N,N-Diisopropylethylamine

[0114] TEA: Triethylamine

[0115] NMM: N-methylmorpholine

[0116] NMI: N-methylimidazole

[0117] Cy2NMe: Dicyclohexylmethylamine

[0118] DMAP: 4-N,N-Dimethylaminopyridine

[0119] T3P: n-propylphosphonic anhydride

[0120] HATU: O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethylureonium hexafluorophosphate or 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate

[0121] COMU: (1-cyano-2-ethoxy-2-oxoethyleneaminooxy)dimethylaminomorpholinylcarbomonium hexafluorophosphate or 2-cyano-2-((dimethylimino)(morpholinyl)methyloxime)ethyl acetate hexafluorophosphate

[0122] DEPC: Diethyl chlorophosphate

[0123] DPPC: Diphenyl Chlorophosphate

[0124] HOPO: 2-hydroxypyridine-N-oxide

[0125] H3PO4: Phosphoric acid

[0126] NaCl: Sodium chloride

[0127] Na2CO3: Sodium carbonate

[0128] K2CO3: Potassium carbonate

[0129] NaHCO3: Sodium bicarbonate

[0130] NaHSO4: Sodium bisulfate

[0131] Na2SO4: Sodium sulfate

[0132] H2O: water

[0133] TFA: Trifluoroacetic acid

[0134] HMDS: Hexamethyldisilazane

[0135] TMSOTf: Trimethylsilyl trifluoromethanesulfonate

[0136] Pd / C: Palladium supported on carbon

[0137] HOAt: 1-Hydroxy-7-azabenzotriazole (HOAt)

[0138] HOOBt: 3-hydroxy-1,2,3-benzotriazine-4-one

[0139] HOCt: Ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate

[0140] HOSu: N-hydroxysuccinimide

[0141] HONB: N-hydroxy-5-norbornene-2,3-dicarboximide

[0142] HOPht: N-hydroxyphthalimide

[0143] EDC·HCl: 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride

[0144] DIC: N,N'-Diisopropylcarbodiimide

[0145] CDI: 1,1'-carbonyldiimidazole

[0146] MNBA: 2-Methyl-6-nitrobenzoic anhydride

[0147] TCFH: Chloro-N,N,N',N'-Tetramethylformamidinium hexafluorophosphate

[0148] TPTU: O-[2-oxo-1(2H)-pyridyl]-N,N,N',N'-tetramethylureonium tetrafluoroborate

[0149] BEP: 2-Bromo-1-ethylpyridinium tetrafluoroborate

[0150] Ph2CP: Salicylateamino-2-benzylthiophenol

[0151] DEPBT: 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazine-4(3H)-one

[0152] TDBTU: O-(3,4-dihydro-4-oxo-1,2,3-benzotriazine-3-yl)-N,N,N',N'-tetramethylureonium tetrafluoroborate

[0153] DPPA: Diphenyl phosphate azide

[0154] FDPP: Pentafluorophenyl diphenylphosphonite

[0155] p-TsCl: p-Toluenesulfonyl chloride

[0156] HOTU: O-[(ethoxycarbonyl)cyanomethyleneamino]-N,N,N',N'-tetramethylureonium hexafluorophosphate

[0157] Oxyma: Ethyl 2-cyano-2-(hydroxyimino)acetate

[0158] Oxyma-B: 5-(hydroxyimino)-1,3-dimethylpyrimidin-2,4,6-(1H,3H,5H)-trione

[0159] K-Oxyma: Potassium salt of (hydroxyimino) cyanoethyl ester

[0160] PfpOH: 2,2,3,3,3-pentafluoro-1-propanol

[0161] Definitions of functional groups, etc. (The terms explained below are illustrative and not intended to be particularly limiting, and are terms that will be commonly understood by those skilled in the art.)

[0162] As used herein, the term "halogen" includes fluorine, chlorine, bromine, and iodine. As used herein, F refers to fluorine, Cl refers to chlorine, Br refers to bromine, and I refers to iodine. Examples of halogens include fluorine, chlorine, and bromine, and preferably include fluorine and chlorine.

[0163] As used herein, the term "alkyl" refers to a straight-chain or branched monovalent saturated hydrocarbon group derived from an aliphatic saturated hydrocarbon by removing any one of its hydrogen atoms. This group has a subset of hydrocarbon groups or hydrocarbon groups with a main chain containing hydrogen and carbon atoms and free of heteroatoms (atoms other than carbon and hydrogen atoms) or unsaturated carbon-carbon bonds. Alkyl groups include not only straight-chain alkyl groups but also branched alkyl groups. Specifically, the alkyl group is one having 1 to 20 carbon atoms (C1-C2). 20 Alkyl groups, preferably C1-C 10 Alkyl, more preferably C1-C6 alkyl. In the following, "C" refers to... p -C q"This means it has p to q carbon atoms. Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl (2-methylpropyl), n-pentyl, sec-pentyl (1-methylbutyl), tert-pentyl (1,1-dimethylpropyl), neopentyl (2,2-dimethylpropyl), isopentyl (3-methylbutyl), 3-pentyl (1-ethylpropyl), 1,2-dimethylpropyl, 2-methylbutyl, n-hexyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1,1,2,2-tetramethylpropyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, and 2-ethylbutyl. Straight-chain C1-C6" Specific examples of alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl. Straight-chain C1-C3 alkyl groups include methyl, ethyl, and n-propyl. Branched-chain C3-C6 alkyl groups... Specific examples of alkyl groups include isopropyl, sec-butyl, tert-butyl, isobutyl (2-methylpropyl), sec-pentyl (1-methylbutyl), tert-pentyl (1,1-dimethylpropyl), neopentyl (2,2-dimethylpropyl), isopentyl (3-methylbutyl), 3-pentyl (1-ethylpropyl), 1,2-dimethylpropyl, 2-methylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1,1,2,2-tetramethylpropyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, and 2-ethylbutyl.

[0164] As used herein, "alkenyl" refers to a straight-chain or branched monovalent unsaturated hydrocarbon group having one or more carbon-carbon double bonds (bonds between two adjacent sp2 carbon atoms). Depending on the conformation of the atom or group attached to the sp2 carbon atom, the geometry of the double bond can be entgegen (E) or zusammen (Z) and cis or trans conformations. Alkenyl groups are, for example, C2-C. 10 The alkenyl group is preferably C2-C8 alkenyl, more preferably C2-C7 alkenyl, and most preferably C2-C6 alkenyl. Specific examples of alkenyl groups include vinyl, 1-propenyl, 2-propenyl (allyl), isopropenyl, 1-butenyl, 2-butenyl (including cis and trans), 3-butenyl, pentenyl, and hexenyl.

[0165] As used herein, "alkynyl" refers to a straight-chain or branched monovalent unsaturated hydrocarbon group having one or more carbon-carbon triple bonds (bonds between two adjacent sp carbon atoms). An alkynyl group is, for example, C2-C. 10The alkynyl group is preferably C2-C8 alkynyl, more preferably C2-C7 alkynyl, and most preferably C2-C6 alkynyl. Specific examples of alkynyl groups include ethynyl, 1-propynyl, propynyl (2-propynyl), 1-butynyl, 2-butynyl, 3-butynyl, pentynyl, and hexynyl.

[0166] As used herein, "cycloalkyl" refers to a saturated or partially saturated cyclic monovalent non-aromatic hydrocarbon cyclic group (alicyclic cyclic group). It can oxidize the carbon atoms constituting the ring to form a carbonyl group. Cycloalkyl groups can be selected from the group consisting of monocyclic, fused, and spirocyclic rings. As used herein, cycloalkyl groups containing a monocyclic ring are called monocyclic cycloalkyl or monocyclic alicyclic cyclic groups; cycloalkyl groups containing a fused ring are called fused-ring cycloalkyl or fused-ring alicyclic cyclic groups; and cycloalkyl groups containing a spirocyclic ring are called spirocyclic cycloalkyl or spirocyclic alicyclic cyclic groups. Cycloalkyl groups can form fused rings with saturated alicyclic rings such as cyclopentane or cyclohexane, unsaturated alicyclic rings such as cyclopentene or cyclohexene, or aromatic hydrocarbon rings such as benzene or naphthalene. Cycloalkyl groups can form spirocyclic rings with saturated alicyclic rings such as cyclopropane, cyclobutane, cyclopentane, or cyclohexane. Cycloalkyl groups are, for example, C3-C 10 Cycloalkyl, preferably C3-C8 cycloalkyl, more preferably C3-C7 cycloalkyl, and most preferably C3-C6 cycloalkyl. Specific examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclo[2.2.1]heptyl, spiro[3.3]heptyl, and cyclohexenyl.

[0167] As used herein, "aryl" refers to a monovalent aromatic hydrocarbon cyclic group consisting of a monovalent monocyclic or fused ring exhibiting aromaticity. For example, aryl groups are C6-C... 14 Aryl group, preferably C6 aryl, C 10 Aryl and C 14 Aryl, more preferably C6 aryl and C 10 Aryl, most preferably C6 aryl. Specific examples of aryl include phenyl, 1-naphthyl, 2-naphthyl, tolyl, and xylyl.

[0168] As used herein, a "heterocyclic group" is a heterocyclic group containing, in addition to a carbon atom, heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms as the constituent atoms of a ring, preferably containing 1 to 5 heteroatoms, more preferably 1 to 3 heteroatoms, and may have double and / or triple bonds in the ring. The carbon atoms in the ring of the heterocyclic group can be oxidized to form a carbonyl group. As used herein, a heterocyclic group containing a monocyclic ring is called a monocyclic heterocyclic group; a heterocyclic group containing a fused ring is called a fused-ring heterocyclic group; and a heterocyclic group containing a spirocyclic ring is called a spirocyclic heterocyclic group. Heterocyclic groups can form fused or spirocyclic rings with saturated alicyclic rings such as cyclopentane or cyclohexane rings or saturated heterocycles such as tetrahydropyran, dioxane, or pyrrolidine rings. The number of atoms in the ring constituting the heterocyclic group is, for example, 3 to 14 (3-membered to 14-membered heterocyclic group), preferably 3 to 12 (3-membered to 12-membered heterocyclic group), more preferably 3 to 10 (3-membered to 10-membered heterocyclic group), and most preferably 4 to 7 (4-membered to 7-membered heterocyclic group). Specific examples of heterocyclic groups include azo-butyl, ethylene oxide, oxo-butyl, thio-butyl, tetrahydrofuranyl, pyrrolyl, pyrazolyl, imidazoyl, oxazolyl, isoxazolyl, thiazoyl, isothiazolyl, thiadiazoyl, oxoxazolyl, dioxopentyl, tetrahydropyranyl, morpholinyl, thiomorpholinyl, 4-oxopyrrolyl, piperidinyl, 4-oxopyridinyl, piperazine, and dioxyl, as well as rings in which one or more single bonds in these saturated heterocycles are replaced by double or triple bonds.

[0169] As used herein, "heteroaryl" refers to a monovalent aromatic heterocyclic group containing at least one heteroatom in addition to a carbon atom and consisting of a monocyclic or fused ring exhibiting aromaticity. As used herein, a heteroaryl group consisting of a monocyclic ring is called a monocyclic heteroaryl, and a heteroaryl group consisting of a fused ring is called a fused-ring heteroaryl. The number of atoms in the ring constituting the heteroaryl is, for example, 5 to 14 (5-membered to 14-membered heteroaryl), preferably 5 to 13 (5-membered to 13-membered heteroaryl), more preferably 5 to 10 (5-membered to 10-membered heteroaryl), and most preferably 5 to 7 (5-membered to 7-membered heteroaryl). Specific examples of heteroaryl groups include 5-membered heteroaryl groups, such as furanyl, thiopheneyl, pyrroleyl, imidazolyl, pyrazolyl, thiazolyl, oxazolyl, triazolyl, or tetrazolyl; 6-membered heteroaryl groups, such as pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, or triazinyl; 9-membered heteroaryl groups, such as benzofuranyl, benzothiopheneyl, benzothiazolyl, benzoimidazolyl, benzotriazolyl, indolyl, inazolyl, or pyrazolopyridyl; and 10-membered heteroaryl groups, such as quinolinyl, isoquinolinyl, cyclolinyl, quinazolinyl, or quinoxalinyl.

[0170] As used herein, “alkoxy” is a group (-OR, where R is an alkyl group) that connects an alkyl group to an oxygen atom as defined herein. Alkoxy groups are, for example, C1-C 20 Alkoxy groups, preferably C1-C 10 Alkoxy groups, more preferably C1-C8 alkoxy groups, and most preferably C1-C6 alkoxy groups. Specific examples of alkoxy groups include methoxy, ethoxy, 1-propoxy, 2-propoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, and 3-methylbutoxy.

[0171] As used herein, "alkenyloxy group" is a group (-OR, where R is an alkenyl group) that connects an alkenyl group to an oxygen atom as defined herein. Alkenyloxy groups are, for example, C2-C. 10 The alkenyloxy group is preferably a C2-C8 alkenyloxy group, more preferably a C2-C7 alkenyloxy group, and most preferably a C2-C6 alkenyloxy group. Specific examples of alkenyloxy groups include vinyl(vinyl)oxy, 1-propenyloxy, 2-propenyl(allyl)oxy, isopropenyloxy, 1-butenyloxy, 2-cis-butenyloxy, 2-trans-butenyloxy, 3-butenyloxy, pentenyloxy, and hexenyloxy.

[0172] As used herein, “cycloalkoxy” is a group (-OR, where R is a cycloalkyl group) that links a “cycloalkyl” group to an oxygen atom as defined herein. Cycloalkoxy groups are, for example, C3-C… 10 Cycloalkoxy groups are preferably C3-C8 cycloalkoxy groups, more preferably C3-C7 cycloalkoxy groups, and most preferably C3-C6 cycloalkoxy groups. Specific examples of cycloalkoxy groups include cyclopropoxy, cyclobutoxy, and cyclopentoxy groups.

[0173] As used herein, “aryloxy group” is a group (-OAr, where Ar is an aryl group) that connects an aryl group as defined herein to an oxygen atom. Aryloxy groups are, for example, C6-C. 14 Aryloxy group, preferably C6 aryloxy group, C 10 aryloxy groups and C 14 aryloxy groups, more preferably C6 aryloxy groups and C6 aryloxy groups. 10 Aryloxy group, most preferably C6 aryloxy group. Specific examples of aryloxy groups include phenoxy, 1-naphthyloxy, 2-naphthyloxy, tolyloxy, and xyloxy.

[0174] As used herein, “amino” means -NRR’, where N represents a nitrogen atom and R and R’ are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, and heteroaryl groups, or R and R’ together with the nitrogen atom to which they are attached form a ring. Examples of amino groups include -NH2, mono-C1-C6 alkylamino, di-C1-C6 alkylamino, and 4- to 8-membered cyclic amino groups.

[0175] As used herein, "monoalkylamino" refers to an amino (-NRR') group as defined above, where R is a hydrogen atom and R' is an alkyl group. Monoalkylamino groups are, for example, C1-C 20 Alkylamino, preferably mono-C1-C 15 Alkylamino, more preferably mono-C1-C 10 Alkylamino, most preferably mono-C1-C6 alkylamino. Specific examples of mono-alkylamino include methylamino, ethylamino, n-propylamino, isopropylamino, n-butylamino, sec-butylamino, and tert-butylamino.

[0176] As used herein, “dialkylamino” means an amino (-NRR') group as defined herein, where R and R' are each independently an alkyl group. Dialkylamino groups are, for example, C1-C 20 Alkylamino, preferably di-C1-C 15 Alkylamino, more preferably di-C1-C 10 Alkylamino, most preferably di-C1-C6 alkylamino. Specific examples of dialkylamino include dimethylamino, diethylamino, and methylethylamino.

[0177] As used herein, “cyclic amino” is a group of “amino (-NRR’)” as defined herein, wherein R and R’ together with the nitrogen atom to which they are attached form a ring. Cyclic amino groups are, for example, 3- to 14-membered cyclic amino groups, preferably 3- to 12-membered cyclic amino groups, more preferably 3- to 10-membered cyclic amino groups, and most preferably 4- to 7-membered cyclic amino groups. Specific examples of cyclic amino groups include 1-azacyclobutane, 1-pyrrolidinyl, 1-piperidinyl, 1-piperazinyl, 4-morpholinyl, 3-oxazolidinyl, 1,1-thiomorpholinyl-4-yl, and 3-oxa-8-azabicyclo[3.2.1]octane-8-yl.

[0178] As used herein, “protected amino” means an amino group protected by an optional protecting group. Specific examples of protected amino groups include those protected by protecting groups such as Boc (tert-butoxycarbonyl), Fmoc (9-fluorenylmethoxycarbonyl), Cbz (benzyloxycarbonyl), Troc (2,2,2-trichloroethoxycarbonyl), Alloc (allyloxycarbonyl), Teoc (2-(trimethylsilyl)ethoxycarbonyl), or trifluoroacetyl.

[0179] As used herein, "aminocarbonyl" refers to a group in which an amino group, as defined herein, connects a carbon atom to a carbonyl group. It is sometimes also called an amide. Examples of aminocarbonyl groups include -CONH2, mono-C1-C6 alkylaminocarbonyl, di-C1-C6 alkylaminocarbonyl, and 4- to 8-membered cyclic aminocarbonyl groups. Specific examples of aminocarbonyl groups include -CONH2, methylaminocarbonyl, ethylaminocarbonyl, dimethylaminocarbonyl, diethylaminocarbonyl, 1-azacyclobutylcarbonyl, 1-pyrrolidinylcarbonyl, 1-piperidinylcarbonyl, 1-piperazinylcarbonyl, 4-morpholinylcarbonyl, and 3-oxazolylalkylcarbonyl.

[0180] As used herein, "alkenyloxycarbonyl" refers to a carbonyl group attached to an "alkenyloxy" group as defined herein. An alkenyloxycarbonyl group is, for example, C2-C. 10 The alkenyloxycarbonyl group is preferably a C2-C8 alkenyloxycarbonyl group, more preferably a C2-C7 alkenyloxycarbonyl group, and most preferably a C2-C6 alkenyloxycarbonyl group. Specific examples of alkenyloxycarbonyl groups include vinyl(vinyl)oxycarbonyl, 1-propenyloxycarbonyl, 2-propenyl(allyl)oxycarbonyl, isopropenyloxycarbonyl, 1-butenyloxycarbonyl, 2-cis-butenyloxycarbonyl, 2-trans-butenyloxycarbonyl, 3-butenyloxycarbonyl, pentenyloxycarbonyl, and hexenyloxycarbonyl.

[0181] As used herein, “alkylsulfonyl” refers to a sulfonyl group attached to an alkyl group as defined herein. Alkylsulfonyl groups are, for example, C1-C2. 20 Alkyl sulfonyl group, preferably C1-C 10 Alkyl sulfonyl, more preferably C1-C8 alkyl sulfonyl, and most preferably C1-C6 alkyl sulfonyl. Specific examples of alkyl sulfinyl groups include methanesulfonyl, ethyl sulfonyl, 1-propyl sulfonyl, 2-propyl sulfonyl, n-butyl sulfonyl, isobutyl sulfonyl, sec-butyl sulfonyl, tert-butyl sulfonyl, pentyl sulfonyl, and 3-methylbutyl sulfonyl.

[0182] As used herein, "hydroxyalkyl" is a group in which one or more hydrogen atoms of an alkyl group, as defined herein, are replaced by a hydroxyl group. Preferably, a hydroxyalkyl group is a group in which one hydrogen atom of an alkyl group is replaced by a hydroxyl group. Hydroxyalkyl groups are, for example, hydroxyl C1-C1 groups. 20 Alkyl groups, preferably hydroxyl C1-C 10 Alkyl groups, more preferably hydroxy C1-C8 alkyl groups, and most preferably hydroxy C1-C6 alkyl groups. Specific examples of hydroxyalkyl groups include hydroxyethyl, 1-hydroxyethyl, 2-hydroxyethyl, 2-hydroxy-2-methylpropyl, and 5-hydroxypentyl.

[0183] As used herein, "halogenated alkyl" is a group in which one or more hydrogen atoms of an alkyl group as defined herein are replaced by a halogen. Halogenated alkyl is preferably a group in which one or more and six or fewer hydrogen atoms of the alkyl group are permitted to be substituted with a halogen. Halogenated alkyl groups are, for example, halogenated-C1-C. 20 Alkyl groups, preferably halogenated -C1-C 10 Alkyl groups, more preferably halo-C1-C8 alkyl groups, and most preferably halo-C1-C6 alkyl groups. Halo-C1-C6 alkyl groups are, for example, groups in which one or more and six or fewer hydrogen atoms of the alkyl group are substituted with fluorine, preferably groups in which one or more and five or fewer hydrogen atoms are substituted with fluorine, more preferably groups in which one or more and four or fewer hydrogen atoms are substituted with fluorine, and most preferably groups in which one or more and three or fewer hydrogen atoms are substituted with fluorine. Specific examples of haloalkyl groups include difluoromethyl, trifluoromethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 3,3-difluoropropyl, 4,4-difluorobutyl, and 5,5-difluoropentyl.

[0184] As used herein, "cyanoalkyl" is a group in which one or more hydrogen atoms of an alkyl group are replaced by a cyano group. Cyanoalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by a cyano group. Cyanoalkyl is, for example, a cyano C1-C... 20 Alkyl groups, preferably cyano C1-C 10 Alkyl groups, more preferably cyanoC1-C8 alkyl groups, and most preferably cyanoC1-C6 alkyl groups. Specific examples of cyanoalkyl groups include cyanomethyl and 2-cyanoethyl.

[0185] As used herein, "aminoalkyl" is a group in which one or more hydrogen atoms of an alkyl group as defined herein are replaced by a cyano group. Preferably, an aminoalkyl group is a group in which one hydrogen atom of an alkyl group is replaced by an amino group. Aminoalkyl groups are, for example, amino C1-C... 20 Alkyl groups, preferably amino C1-C 10Alkyl groups, more preferably amino C1-C8 alkyl groups, and most preferably amino C1-C6 alkyl groups. Specific examples of aminoalkyl groups include aminomethyl, aminoethyl, 4-aminobutyl, methylaminomethyl, dimethylaminomethyl, methylaminoethyl, and dimethylaminoethyl.

[0186] As used herein, "carboxyalkyl" is a group in which one or more hydrogen atoms of an alkyl group, as defined herein, are replaced by a carboxyl group. Carboxyalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by a carboxyl group. Carboxyalkyl is, for example, a carboxyl C1-C group. 20 Alkyl groups, preferably carboxyl C1-C 15 Alkyl groups, more preferably carboxyl groups (C1-C), are used. 10 Alkyl groups, most preferably carboxyl C1-C6 alkyl groups. Specific examples of carboxyl alkyl groups include carboxymethyl and carboxyethyl.

[0187] As used herein, "alkenyloxycarbonylalkyl" is a group in which one or more hydrogen atoms of an alkyl group are replaced by an "alkenyloxycarbonyl" group. Preferably, an alkenyloxycarbonylalkyl group is a group in which one hydrogen atom of an alkyl group is replaced by an alkenyloxycarbonyl group. Alkenyloxycarbonylalkyl groups are, for example, C2-C 10 The alkenyloxycarbonyl-C1-C6 alkyl group is preferably a C2-C8 alkenyloxycarbonyl-C1-C6 alkyl group, more preferably a C2-C7 alkenyloxycarbonyl-C1-C6 alkyl group, and most preferably a C2-C6 alkenyloxycarbonyl-C1-C6 alkyl group. Specific examples of alkenyloxycarbonyl alkyl groups include vinyl(vinyl)oxycarbonylmethyl, 1-propenyloxycarbonylethyl, 2-propenyl(allyl)oxycarbonylmethyl, isopropenyloxycarbonylmethyl, 1-butenyloxycarbonylethyl, 2-cis-butenyloxycarbonylmethyl (including cis and trans), 2-trans-butenyloxycarbonylmethyl, 3-butenyloxycarbonylethyl, pentenyloxycarbonylmethyl, and hexenyloxycarbonylethyl.

[0188] As used herein, "alkoxyalkyl" is a group in which one or more hydrogen atoms of an alkyl group, as defined herein, are replaced by an alkoxy group. Alkoxyalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by an alkoxy group. Alkoxyalkyl is, for example, a C1-C6 alkoxy-C1-C 20 Alkyl groups, preferably C1-C6 alkoxy-C1-C 15 Alkyl, more preferably C1-C6 alkoxy-C1-C 10Alkyl, most preferably C1-C6 alkoxy-C1-C6 alkyl. Specific examples of alkoxyalkyl include methoxymethyl, ethoxymethyl, 1-propoxymethyl, 2-propoxymethyl, n-butoxymethyl, isobutoxymethyl, sec-butoxymethyl, tert-butoxymethyl, pentoxymethyl, 3-methylbutoxymethyl, 1-methoxyethyl, 2-methoxyethyl, and 2-ethoxyethyl.

[0189] As used herein, "cycloalkylalkyl" is a group in which one or more hydrogen atoms of an alkyl group as defined herein are replaced by a cycloalkyl group. Preferably, a cycloalkylalkyl group is a group in which one hydrogen atom of an alkyl group is replaced by a cycloalkyl group. Cycloalkylalkyl groups are, for example, C3-C4. 10 cycloalkyl-C1-C 20 Alkyl groups, preferably C3-C 10 The cycloalkyl-C1-C6 alkyl group is more preferably a C3-C8 cycloalkyl-C1-C6 alkyl group, and most preferably a C3-C6 cycloalkyl-C1-C2 alkyl group. Specific examples of cycloalkyl alkyl groups include cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl, cyclohexylethyl, and cyclohexylpropyl.

[0190] As used herein, "cycloalkoxyalkyl" is a group in which one or more hydrogen atoms of an alkyl group as defined herein are replaced by a "cycloalkoxy" group. Cycloalkoxyalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by a "cycloalkoxy" group. Cycloalkoxyalkyl is, for example, C3-C 10 The cycloalkoxy-C1-C6 alkyl group is preferably a C3-C8 cycloalkoxy-C1-C6 alkyl group, more preferably a C3-C7 cycloalkoxy-C1-C6 alkyl group, and most preferably a C3-C6 cycloalkoxy-C1-C6 alkyl group. Specific examples of cycloalkoxy-alkyl groups include cyclopropoxymethyl, cyclobutoxymethyl, and cyclopentoxymethyl.

[0191] As used herein, "heterocyclic alkyl" is a group in which one or more hydrogen atoms of an alkyl group are replaced by a "heterocyclic group". Heterocyclic alkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by a heterocyclic group. Heterocyclic alkyl is, for example, a 3- to 14-membered heterocyclic-C1-C6 alkyl, preferably a 3- to 12-membered heterocyclic-C1-C6 alkyl, more preferably a 3- to 10-membered heterocyclic-C1-C4 alkyl, and most preferably a 4- to 7-membered heterocyclic-C1-C3 alkyl. Specific examples of heterocyclic alkyl include azirrobutane-1-ylmethyl, oxadiazonane-3-ylmethyl, 2-(tetrahydrofuran-3-yl)ethyl, (1-methylpyrrolidine-3-yl)methyl, 2-morpholinylethyl, 3-(1-piperidinyl)propyl, and 3-(4-methylpiperazin-1-yl)propyl.

[0192] As used herein, "alkylsulfonylalkyl" is a group in which one or more hydrogen atoms of an alkyl group are replaced by an alkylsulfonyl group. Alkylsulfonylalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by an alkylsulfonyl group. Alkylsulfonylalkyl is, for example, C1-C1. 20 alkylsulfonyl-C1-C4 alkyl, preferably C1-C 10 Alkylsulfonyl-C1-C4 alkyl, more preferably C1-C8 alkylsulfonyl-C1-C4 alkyl, and most preferably C1-C6 alkylsulfonyl-C1-C4 alkyl. Specific examples of alkylsulfonyl alkyl include methanesulfonylmethyl, methanesulfonylpropyl, methanesulfonylbutyl, ethylsulfonylethyl, 1-propylsulfonylmethyl, 2-propylsulfonylethyl, n-butylsulfonylpropyl, isobutylsulfonylmethyl, sec-butylsulfonylmethyl, tert-butylsulfonylmethyl, pentylsulfonylmethyl, and 3-methylbutylsulfonylmethyl.

[0193] As used herein, "aminocarbonylalkyl" means a group in which one or more hydrogen atoms of an alkyl group are replaced by an aminocarbonyl group as defined herein. Preferably, an aminocarbonylalkyl group is a group in which one hydrogen atom of an alkyl group is replaced by an aminocarbonyl group. For example, an aminocarbonyl-C1-C1 group is an aminocarbonyl-C1 ... 10 Alkyl groups, preferably aminocarbonyl-C1-C6 alkyl groups, more preferably aminocarbonyl-C1-C4 alkyl groups, and most preferably aminocarbonyl-C1-C2 alkyl groups. Specific examples of aminocarbonyl alkyl groups include -CH2CONH2, methylaminocarbonylmethyl, ethylaminocarbonylethyl, dimethylaminocarbonylpropyl, diethylaminocarbonylmethyl, 1-azacyclobutylcarbonylmethyl, 1-pyrrolidinylcarbonylethyl, 1-piperidinylcarbonylpropyl, 1-piperazinylcarbonylbutyl, 4-morpholinylcarbonylmethyl, and 3-oxazolylcarbonylethyl.

[0194] As used herein, "aryloxyalkyl" means a group in which one or more hydrogen atoms of an alkyl group are replaced by an aryloxy group as defined herein. Aryloxyalkyl groups are preferably C6-C. 10 aryloxy-C1-C6 alkyl, more preferably C6-C 10 Aryloxy-C1-C2 alkyl. Specific examples of aryloxyalkyl groups include phenoxymethyl and 2-phenoxyethyl.

[0195] As used herein, "aralkyl" is a group in which one or more hydrogen atoms of "alkyl" are replaced by "aryl" as defined herein. Aralkyl groups are, for example, C7-C 20 Aryl alkyl group, preferably C7-C 18 Aryl alkyl group, more preferably C7-C 16 Aryl alkyl group, most preferably C7-C 14 Aryl group. C7-C 20 Aryl alkyl groups, for example, are C6-C 10 Aryl-C1-C 10 Alkyl groups, preferably C6-C 10 Aryl-C1-C8 alkyl, more preferably C6 aryl-C1-C8 alkyl or C 10 Aryl-C1-C8 alkyl, most preferably C6 aryl-C1-C8 alkyl. C7-C 18 Aryl alkyl groups, for example, are C6-C 10 aryl-C1-C8 alkyl, preferably C6-C 10 aryl-C1-C6 alkyl, more preferably C6 aryl-C1-C6 alkyl or C 10 Aryl-C1-C6 alkyl, most preferably C6 aryl-C1-C6 alkyl. C7-C 16 Aryl alkyl groups, for example, are C6-C 10 aryl-C1-C6 alkyl, preferably C6-C 10 aryl-C1-C4 alkyl, more preferably C6 aryl-C1-C4 alkyl or C 10 Aryl-C1-C4 alkyl, most preferably C6 aryl-C1-C4 alkyl. C7-C 14 Aryl alkyl groups, for example, are C6-C 10 aryl-C1-C4 alkyl, preferably C6-C 10 aryl-C1-C3 alkyl, more preferably C6 aryl-C1-C3 alkyl or C 10Aryl-C1-C3 alkyl, most preferably C6 aryl-C1-C3 alkyl. Specific examples of aryl alkyl groups include benzyl, phenethyl, and 3-phenylpropyl.

[0196] As used herein, “aranalkoxy” is a group (-OR-Ar, where R is an alkylene group) that connects the alkyl portion of an aralkyl group as defined herein to an oxygen atom. Aranalkoxy groups are, for example, C7-C 20 Arylalkoxy groups, preferably C7-C 18 Arylalkoxy, more preferably C7-C 16 Arylalkoxy groups, most preferably C7-C 14 Arylalkoxy group. C7-C 20 Aryl alkoxy groups, for example, are C6-C. 10 Aryl-C1-C 10 Alkoxy groups, preferably C6-C 10 aryl-C1-C8 alkoxy, more preferably C6 aryl-C1-C8 alkoxy or C 10 Aryl-C1-C8 alkoxy, most preferably C6 aryl-C1-C8 alkoxy. C7-C 18 Aryl alkoxy groups, for example, are C6-C. 10 aryl-C1-C8 alkoxy, preferably C6-C 10 aryl-C1-C6 alkoxy, more preferably C6 aryl-C1-C6 alkoxy or C 10 Aryl-C1-C6 alkoxy, most preferably C6 aryl-C1-C6 alkoxy. C7-C 16 Aryl alkoxy groups, for example, are C6-C. 10 aryl-C1-C6 alkoxy, preferably C6-C 10 aryl-C1-C4 alkoxy, more preferably C6 aryl-C1-C4 alkoxy or C 10 Aryl-C1-C4 alkoxy, most preferably C6 aryl-C1-C4 alkoxy. C7-C 14 Aryl alkoxy groups, for example, are C6-C. 10 aryl-C1-C4 alkoxy, preferably C6-C 10 aryl-C1-C3 alkoxy, more preferably C6 aryl-C1-C3 alkoxy or C 10 Aryl-C1-C3 alkoxy, most preferably C6 aryl-C1-C3 alkoxy. Specific examples of arylalkoxy groups include benzyloxy, phenylethoxy, and 3-phenylpropoxy.

[0197] As used herein, "aralkyloxyalkyl" means a group in which one or more hydrogen atoms of an alkyl group are replaced by an aralkyl group as defined herein. Aralkyloxyalkyl groups are preferably C7-C. 14 Arylalkoxy-C1-C6 alkyl, more preferably C7-C 14 Ararylalkoxy-C1-C2 alkyl. Specific examples of ararylalkoxyalkyl groups include benzyloxymethyl and 1-(benzyloxy)ethyl.

[0198] As used herein, "heteroarylalkyl" is a group in which one or more hydrogen atoms of an alkyl group are replaced by a "heteroaryl" group. Heteroarylalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by a heteroaryl group. Heteroarylalkyl is, for example, a 5- to 10-membered heteroaryl-C1-C6 alkyl, preferably a 5- to 10-membered heteroaryl-C1-C4 alkyl, more preferably a 5- to 10-membered heteroaryl-C1-C3 alkyl, and most preferably a 5- to 10-membered heteroaryl-C1-C2 alkyl. Specific examples of heteroarylalkyl include 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl, 2-furanylmethyl, 2-thienylmethyl, 3-thienylmethyl, and 4-thiazolylmethyl.

[0199] As used herein, "heteroarylalkoxy" is a group that connects the alkyl portion of "heteroarylalkyl" as defined herein to an oxygen atom. Heteroarylalkoxy groups are, for example, 5- to 10-membered heteroaryl-C1-C6 alkoxy groups, preferably 5- to 10-membered heteroaryl-C1-C4 alkoxy groups, more preferably 5- to 10-membered heteroaryl-C1-C3 alkoxy groups, and most preferably 5- to 10-membered heteroaryl-C1-C2 alkoxy groups. Specific examples of heteroarylalkoxy groups include 2-pyridylmethoxy, 3-pyridylmethoxy, 4-pyridylmethoxy, 2-furanylmethoxy, 2-thienylmethoxy, 3-thienylmethoxy, and 4-thiazolylmethoxy.

[0200] As used herein, "heteroarylalkoxyalkyl" means a group in which one or more hydrogen atoms of an alkyl group are replaced by a "heteroarylalkoxy" as defined herein. Heteroarylalkoxyalkyl is preferably a group in which one hydrogen atom of an alkyl group is replaced by a heteroarylalkoxy. Heteroarylalkoxyalkyl is, for example, a 5- to 10-membered heteroaryl-C1-C6 alkoxy-C1-C6 alkyl, preferably a 5- to 10-membered heteroaryl-C1-C4 alkoxy-C1-C6 alkyl, more preferably a 5- to 10-membered heteroaryl-C1-C3 alkoxy-C1-C6 alkyl, and most preferably a 5- to 10-membered heteroaryl-C1-C2 alkoxy-C1-C6 alkyl. Specific examples of heteroarylalkoxyalkyl groups include 2-pyridylmethoxymethyl, 3-pyridylmethoxymethyl, 4-pyridylmethoxymethyl, 2-furanylmethoxymethyl, 2-thienylmethoxymethyl, 3-thienylmethoxymethyl, and 4-thiazolylmethoxymethyl.

[0201] As used herein, "heterocyclic alkyl alkyl" means a group in which one or more hydrogen atoms of an alkyl group are replaced by a "heterocyclic alkyl" as defined herein. Heterocyclic alkyl alkyl is preferably a 4- to 7-membered heterocyclic alkyl-C1-C6 alkyl, more preferably a 4- to 7-membered heterocyclic alkyl-C1-C2 alkyl. Specific examples of heteroarylalkoxyalkyl include tetrahydro-4H-pyran-4-ylemethylene and azirmonobutane-3-ylemethylene.

[0202] As used herein, "alkoxyalkenyl" is a group in which one or more hydrogen atoms of an "alkenyl" group, as defined herein, are replaced by an "alkoxy group". Preferably, an alkoxyalkenyl group is a group in which one hydrogen atom of an alkenyl group is replaced by an alkoxy group. Alkoxyalkenyl groups are, for example, C1-C6 alkoxy-C2-C... 10 Alkenyl, preferably C1-C6 alkoxy-C2-C8 alkenyl, more preferably C1-C6 alkoxy-C2-C7 alkenyl, and most preferably C1-C6 alkoxy-C2-C6 alkenyl. Specific examples of alkoxyalkenyl include (E)-4-methoxybut-2-en-1-yl.

[0203] As used herein, "aminocarbonylalkenyl" is a group in which one or more hydrogen atoms of an "alkenyl" group, as defined herein, are replaced by an "aminocarbonyl" group. Preferably, an aminocarbonylalkenyl group is a group in which one hydrogen atom of an alkenyl group is replaced by an aminocarbonyl group. An example of an aminocarbonylalkenyl group is aminocarbonyl-C2-C... 10The alkenyl group is preferably an aminocarbonyl-C2-C8 alkenyl group, more preferably an aminocarbonyl-C2-C6 alkenyl group, and most preferably an aminocarbonyl-C2-C4 alkenyl group. Specific examples of aminocarbonyl alkenyl groups include (E)-3-(dimethylaminocarbonyl)-prop-2-en-1-yl.

[0204] As used herein, "haloalkoxy" is a group in which one or more hydrogen atoms of an alkoxy group as defined herein are substituted with a halogen. Haloalkoxy is preferably a group in which one or more and six or fewer hydrogen atoms of the alkoxy group are permitted to be substituted with a halogen. Haloalkoxy groups are, for example, halogen-C1-C. 20 Alkoxy groups, preferably halogenated -C1-C 10 Alkoxy groups, more preferably halo-C1-C8 alkoxy groups, and most preferably halo-C1-C6 alkoxy groups. Halo-C1-C6 alkoxy groups are, for example, groups in which one or more and six or fewer hydrogen atoms of the alkoxy group are substituted with fluorine, preferably groups in which one or more and five or fewer hydrogen atoms are substituted with fluorine, more preferably groups in which one or more and four or fewer hydrogen atoms are substituted with fluorine, and most preferably groups in which one or more and three or fewer hydrogen atoms are substituted with fluorine. Specific examples of haloalkoxy groups include difluoromethoxy, trifluoromethoxy, 2,2-difluoroethoxy, 2,2,2-trifluoroethoxy, 3-fluoropropoxy, and 2,2-difluoropropoxy.

[0205] As used herein, "alkylene" means a divalent group resulting from the further removal of any hydrogen atom from an "alkyl" as described herein. Alkylenes are preferably C1-C8 alkylenes, more preferably C4-C8 alkylenes. Specific examples of alkylenes include -CH2-, -(CH2)2-, -(CH2)3-, -CH(CH3)CH2-, -C(CH3)2-, -(CH2)4-, -CH(CH3)CH2CH2-, -C(CH3)2CH2-, -CH2CH(CH3)CH2-, -CH2C(CH3)2-, -CH2CH2CH(CH3)-, -CH2CH(CH2CH3)-, -(CH2)5-, -CH(CH3)CH(CH2CH3)-, -(CH2)6-, -(CH2)7-, and -(CH2)8-.

[0206] The term "alicyclic ring" in this article refers to a saturated or partially saturated non-aromatic hydrocarbon ring. The carbon atoms constituting the ring can be oxidized to form a carbonyl group. Alicyclic rings can be selected from the group consisting of monocyclic, fused, and spirocyclic rings. As used herein, an alicyclic ring containing a monocyclic ring is called a monocyclic alicyclic ring; an alicyclic ring containing a fused ring is called a fused-ring alicyclic ring; and an alicyclic ring containing a spirocyclic ring is called a spirocyclic alicyclic ring. Alicyclic rings can form fused rings with saturated alicyclic rings such as cyclopentane or cyclohexane rings, unsaturated alicyclic rings such as cycloheptene or cyclohexene rings, or aromatic hydrocarbon rings such as benzene or naphthalene rings. Alicyclic rings can form spirocyclic rings with saturated alicyclic rings such as cyclopropane, cyclobutane, cyclopentane, or cyclohexane rings. Alicyclic rings are, for example, C3-C 10 Alicyclic rings, preferably C3-C8 alicyclic rings, more preferably C3-C7 alicyclic rings, and most preferably C3-C6 alicyclic rings. Specific examples of alicyclic rings include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, cycloheptane rings, cyclooctane rings, bicyclic [2.2.1]heptane rings, and cyclohexene rings.

[0207] As used herein, a “saturated heterocycle” is a ring that does not have unsaturated bonds in the ring. The number of atoms constituting the saturated heterocycle is from 3 to 14 (3-membered to 14-membered heterocycles), preferably from 3 to 12 (3-membered to 12-membered heterocycles), more preferably from 3 to 10 (3-membered to 10-membered heterocycles), and most preferably from 4 to 7 (4-membered to 7-membered heterocycles). Specific examples of saturated heterocycles include nitrogen-containing butane rings, epoxy rings, oxo-containing butane rings, thio-containing butane rings, tetrahydrofuran rings, pyrrolidine rings, pyrazolidine rings, imidazoline rings, oxazolidine rings, isoxazolidine rings, thiazoline rings, isothiazolidine rings, thiadiazolidine rings, oxazolidine ketone rings, dioxolane rings, tetrahydropyran rings, morpholine rings, thiomorpholine rings, 4-oxopyrrolidine rings, piperidine rings, 4-oxopyridine rings, piperazine rings, and dioxane rings.

[0208] As used herein, "peptide compound" refers to a compound in which two or more amino acids are linked by amide bonds. While two or more amino acids are linked by amide bonds, the peptide chain may contain other bonds such as ester or thioester bonds. Examples of the number of amino acid residues contained in a peptide range from 5 to 30 residues. Peptides can be linear, branched, or cyclic.

[0209] As used herein, "peptide chain" refers to the chain-like portion of a peptide in which two or more amino acids are linked by amide bonds. While two or more amino acids are linked by amide bonds, a peptide chain may contain other bonds such as ester or thioester bonds. Examples of the number of amino acid residues contained in a peptide chain range from 5 to 30 residues.

[0210] As used herein, "optionally substituted" means that a particular group and / or a particular atom may be substituted with optional substituents and / or optional atoms. That is, a state in which a particular group and a particular atom are neither substituted with optional substituents nor with optional atoms may be selected, or a state in which a particular group and / or a particular atom are substituted with optional substituents and / or optional atoms. Each of the particular group and / or particular atoms may be further substituted with optional substituents and / or optional atoms. That is, a state in which a particular group and particular atom are not substituted with optional substituents or optional atoms may be selected, for example, in a state in which a particular group and / or particular atom are substituted with optional substituents and / or optional atoms. The particular group and optional substituents are not limited and may be freely selected, for example, from groups containing atoms selected from the group consisting of hydrogen, halogen, carbon, oxygen, sulfur, nitrogen, boron, silicon, and phosphorus atoms. The particular atom and optional atom are not limited and may be freely selected, for example, from halogen, carbon, oxygen, sulfur, nitrogen, boron, silicon, and phosphorus atoms. Examples of optional substituents include alkyl, alkoxy, fluoroalkyl, fluoroalkoxy, oxo, aminocarbonyl, alkylsulfonyl, alkylsulfonylamino, cycloalkyl, aryl, heteroaryl, heterocyclic, arylalkyl, heteroarylalkyl, halogen, nitro, amino, monoalkylamino, dialkylamino, cyano, carboxyl, alkoxycarbonyl, and formyl.

[0211] As used in this article, "optionally protected" means that the group can be protected by an optional protecting group.

[0212] As used herein, “one or more” means a number of 1 or 2 or more. When “one or more” is used in a context relating to substituents of a group, the term means a number from one to the maximum number of substituents permitted for that group. In particular, “one or more” includes, for example, numbers of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and / or greater.

[0213] The compounds described herein, or their salts, may be their solvates. Examples of salts of the compounds include: hydrochlorides; hydrobroms; hydroiodates; phosphates; phosphonates; sulfates; sulfonates, such as methanesulfonates and p-toluenesulfonates; carboxylates, such as acetates, citrates, malates, tartrates, succinates, and salicylates; alkali metal salts, such as sodium and potassium salts; alkaline earth metal salts, such as magnesium and calcium salts; and ammonium salts, such as ammonium salts, alkylammonium salts, dialkylammonium salts, trialkylammonium salts, and tetraalkylammonium salts. These salts may be generated, for example, by contacting the compound with an acid or base. As used herein, a solvate means a solvate in which the compound and the solvent together form a molecular aggregate, and is not particularly limited, provided that it is a solvate formed from a solvent acceptable for uptake in conjunction with the administration of a drug. Specific examples of solvates include not only solvates formed with a single solvent such as water, alcohol (ethanol, methanol, 1-propanol, 2-propanol, or the like), or dimethyl sulfoxide, but also solvates formed by each compound molecule with multiple solvents or by each compound molecule with multiple types of solvents. For example, a solvate formed by a compound with water is called a hydrate. Hydrates are preferred as solvates of the compounds of the present invention. In particular, the hydrate is preferably a 1 to 20 hydrate, more preferably a 1 to 10 hydrate, further preferably a 1 to 5 hydrate, and most preferably a 1 to 3 hydrate.

[0214] As used herein, “amino acid” includes both natural and non-natural amino acids (sometimes referred to as amino acid derivatives). As used herein, “amino acid” may refer to an amino acid residue. As used herein, “natural amino acid” is any L-type amino acid selected from Glycine, L-Ala, L-Ser, L-Thr, L-Val, L-Leu, L-Ile, L-Phe, L-Tyr, L-Trp, L-His, L-Glutamic acid, L-Asp, L-Glutamine, L-Asn, L-Cys, L-Met, L-Lys, L-Arg, or L-Pro. As used herein, “non-natural amino acid” is an amino acid other than a natural amino acid. Examples of non-natural amino acids include β-amino acids, γ-amino acids, D-type amino acids, N-substituted amino acids (except Pro), α,α-disubstituted amino acids, and amino acids having side chains different from those of natural amino acids. As amino acids herein, amino acids of any conformation are acceptable. There are no particular limitations on the side chains of amino acids, and each side chain is freely selected from groups such as alkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaryl, cycloalkyl, or spiro-bonded cycloalkyl, and / or atoms such as hydrogen atoms. Each group and / or atom may further optionally be substituted. In a non-limiting aspect, amino acids as used herein can be compounds having both a carboxyl group and an amino group in the same molecule. Even in this case, amino acids also include compounds in which the nitrogen atom of the amino group of the amino acid and any atom of the side chain together form a ring, such as proline, hydroxyproline, and aziridine-2-carboxylic acid.

[0215] The main chain amino group of an amino acid can be unsubstituted (i.e., an NH2 group) or substituted (i.e., a -NHR group, where R represents an alkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl, or cycloalkyl group optionally having a substituent, and one or both non-adjacent methylene groups of any of these groups can be replaced by an oxygen atom, a carbonyl group (-CO-), or a sulfonyl group (-SO2-); and the carbon chain bonded to the N atom and the carbon atom at the α-position can form a ring, as in proline). The substituents of R are selected in the same manner as those for the substituents of the side chains of amino acids described above. In the case of a substituted main chain amino group, R is included in the term "side chain of amino acid" as used herein. Such amino acids having substituted main chain amino groups are referred to herein as "N-substituted amino acids." Examples of "N-substituted amino acids" as used herein preferably include, but are not limited to, N-alkyl amino acids, N-C1-C6 alkyl amino acids, N-C1-C4 alkyl amino acids, and N-methyl amino acids.

[0216] As used herein, “amino acid” includes all isotopes corresponding to each amino acid. An isotope of an amino acid is one in which at least one atom is replaced by atoms having the same atomic number (number of protons) but different mass numbers (total number of protons and neutrons) at an abundance ratio different from that of the natural amino acid. Examples of isotopes contained in “amino acid” in this document include hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, and chlorine atoms, and they each include… 2 H, 3 H, 13 C 14 C 15 N、 17 O、 18 O、 32 P, 35 S, 18 F, 36 Cl, etc. For compounds as used herein, all compounds containing radioactive or non-radioactive isotopic elements in any proportion are covered within the scope of this invention.

[0217] Examples of “halogen-derived substituents” as used herein include fluorine (-F), chlorine (-Cl), bromine (-Br), and iodine (-I).

[0218] Examples of "substituents containing oxygen atoms" as used herein include hydroxyl (-OH), oxy group (-OR), oxo (=O), carbonyl (-C(=O)-R), carboxyl (-CO2H), oxycarbonyl (-C(=O)-OR), carbonyloxy group (-OC(=O)-R), thiocarbonyl (-C(=O)-SR), carbonylthio (-SC(=O)-R), aminocarbonyl (-C(=O)-NHR), carbonylamino (-NH-C(=O)-R), oxycarbonylamino (-NH-C(=O)-OR), sulfonylamino (-NH-SO2-R), aminosulfonyl (-SO2-NHR), aminosulfonylamino (-NH-SO2-NHR), thiocarboxyl (-C(=O)-SH), and carboxylcarbonyl (-C(=O)-CO2H).

[0219] Examples of alkoxy groups (-OR) include alkoxy, cycloalkoxy, alkenoxy, alkynoxy, aryloxy, heteroaryloxy, and arylalkoxy. Alkoxy groups are preferably C1-C4 alkoxy, C1-C2 alkoxy, and particularly preferably methoxy or ethoxy.

[0220] Examples of carbonyl groups (-C(=O)-R) include formyl (-C(=O)-H), alkyl carbonyl, cycloalkyl carbonyl, alkenyl carbonyl, alkynyl carbonyl, aryl carbonyl, heteroaryl carbonyl, and aralkyl carbonyl.

[0221] Examples of oxycarbonyl groups (-C(=O)-OR) include alkoxycarbonyl, cycloalkoxycarbonyl, alkenoxycarbonyl, alkynoxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, and arylalkoxycarbonyl.

[0222] Examples of carbonyl groups (-OC(=O)-R) include alkyl carbonyl groups, cycloalkyl carbonyl groups, alkenyl carbonyl groups, alkynyl carbonyl groups, aryl carbonyl groups, heteroaryl carbonyl groups, and aralkyl carbonyl groups.

[0223] Examples of thiocarbonyl (-C(=O)-SR) include alkyl thiocarbonyl, cycloalkyl thiocarbonyl, alkenyl thiocarbonyl, alkynyl thiocarbonyl, aryl thiocarbonyl, heteroaryl thiocarbonyl, and aralkyl thiocarbonyl.

[0224] Examples of carbonyl thio groups (-SC(=O)-R) include alkyl carbonyl thio groups, cycloalkyl carbonyl thio groups, alkenyl carbonyl thio groups, alkynyl carbonyl thio groups, aryl carbonyl thio groups, heteroaryl carbonyl thio groups, and aralkyl carbonyl thio groups.

[0225] Examples of aminocarbonyl groups (-(C=O)-NHR) include alkylaminocarbonyl groups (e.g., C1-C6 or C1-C4 alkylaminocarbonyl groups, particularly ethylaminocarbonyl or methylaminocarbonyl groups), cycloalkylaminocarbonyl groups, alkenylaminocarbonyl groups, alkynylaminocarbonyl groups, arylaminocarbonyl groups, heteroarylaminocarbonyl groups, and aralkylaminocarbonyl groups. Additional examples include groups in which the H atom bonded to the N atom in -C(=O)-NHR is further substituted with an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, or aralkyl group.

[0226] Examples of carbonylamino groups (-NH-C(=O)-R) include alkylcarbonylamino, cycloalkylcarbonylamino, alkenylcarbonylamino, alkynylcarbonylamino, arylcarbonylamino, heteroarylcarbonylamino, and aralkylcarbonylamino. Additional examples include groups in which the H atom bonded to the N atom in -NH-C(=O)-R is further substituted with an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, or aralkyl group.

[0227] Examples of oxycarbonylamino groups (-NH-C(=O)-OR) include alkoxycarbonylamino, cycloalkoxycarbonylamino, alkenoxycarbonylamino, alkynoxycarbonylamino, aryloxycarbonylamino, heteroaryloxycarbonylamino, and arylalkoxycarbonylamino. Additional examples include groups in which the H atom bonded to the N atom in -NH-C(=O)-OR is further substituted with an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, or aralkyl group.

[0228] Examples of sulfonylamino (-NH-SO2-R) include alkylsulfonylamino, cycloalkylsulfonylamino, alkenylsulfonylamino, alkynylsulfonylamino, arylsulfonylamino, heteroarylsulfonylamino, and aralkylsulfonylamino. Additional examples include groups in which the H atom bonded to the N atom in -NH-SO2-R is further substituted with an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, or aralkyl group.

[0229] Examples of aminosulfonyl (-SO2-NHR) include alkylaminosulfonyl, cycloalkylaminosulfonyl, alkenylaminosulfonyl, alkynylaminosulfonyl, arylaminosulfonyl, heteroarylaminosulfonyl, and aralkylaminosulfonyl. Additional examples include groups in which the H atom bonded to the N atom in -SO2-NHR is further substituted with an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, or aralkyl group.

[0230] Examples of aminosulfonylamino (-NH-SO2-NHR) include alkylaminosulfonylamino, cycloalkylaminosulfonylamino, alkenylaminosulfonylamino, alkynylaminosulfonylamino, arylaminosulfonylamino, heteroarylaminosulfonylamino, and aralkylaminosulfonylamino. Further, the two H atoms bonded to the N atom in -NH-SO2-NHR may optionally be substituted with substituents independently selected from the group consisting of alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, and aralkyl, and the two substituents may form a ring.

[0231] Examples of "sulfur-containing substituents" as used herein include thiols (-SH), thiols (-SR), sulfinyl groups (-S=OR), sulfonyl groups (-S(O)2-R), sulfonyl groups (-SO3H), pentafluorothiols (-SF5), and dithiols (-SSR).

[0232] Examples of thio groups (-SR) include alkylthio, cycloalkylthio, alkenylthio, alkynylthio, arylthio, heteroarylthio, and aralkylthio.

[0233] Examples of sulfinyl groups (-S=OR) include alkyl sulfinyl groups, cycloalkyl sulfinyl groups, alkenyl sulfinyl groups, alkynyl sulfinyl groups, aryl sulfinyl groups, heteroaryl sulfinyl groups, and aralkyl sulfinyl groups.

[0234] Examples of sulfonyl groups (-S(O)2-R) include alkylsulfonyl, cycloalkylsulfonyl, alkenylsulfonyl, alkynylsulfonyl, arylsulfonyl, heteroarylsulfonyl, and aralkylsulfonyl.

[0235] Examples of "nitrogen-containing substituents" as used herein include azides (-N3, also known as "azido"), cyano (-CN), primary amino (-NH2), secondary amino (-NH-R), tertiary amino (-NR(R')), amido (-C(=NH)-NH2), substituted amido (-C(=NR)-NR'R''), guanidino (-NH-C(=NH)-NH2), substituted guanidino (-NR-C(=NR''')-NR'R''), and aminocarbonylamino (-NR-CO-NR'R'').

[0236] Examples of secondary amino groups (-NH-R) include alkylamino, cycloalkylamino, alkenylamino, alkynylamino, arylamino, heteroarylamino, and aralkylamino.

[0237] Examples of tertiary amino groups (-NR(R')) include amino groups having two optional substituents each independently selected from alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl, etc., such as alkyl (aralkyl)amino groups, and the optional two substituents may form a ring.

[0238] Examples of substituted amidoyl groups (-C(=NR)-NR'R'') include those in which the three substituents R, R', and R'' on the N atom are each independently selected from alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, and aralkyl groups, such as alkyl(aralkyl)(aryl)amidinyl.

[0239] Examples of substituted guanidino groups (-NR-C(=NR''')-NR'R'') include groups in which R, R', R'' and R''' are each independently selected from alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl and aralkyl groups, and groups in which these substituents form a ring.

[0240] Examples of aminocarbonylamino (-NR-CO-NR'R'') include groups in which R, R', and R'' are each independently selected from hydrogen atoms, alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, and aralkyl groups, and groups in which these substituents form a ring.

[0241] As used in this article, the "amino acid residues" that make up peptide compounds are sometimes simply referred to as "amino acids".

[0242] As used in this article, "to" to indicate a range of values ​​includes the values ​​at both ends. For example, "A to B" means a range of values ​​where A is or greater and B is or less.

[0243] As used in this article, the term “about” when used in conjunction with a numerical value means a range of values ​​between +10% and -10% of that value.

[0244] As used herein, the term “and / or” is intended to include each combination of the appropriate combination of the terms “and” and “or”. Specifically, for example, the terms “A, B and / or C” include the following seven variations: (i) A, (ii) B, (iii) C, (iv) A and B, (v) A and C, (vi) B and C, and (vii) A, B and C.

[0245] Methods for producing cyclic peptide compounds

[0246] In one aspect, the present invention relates to a method for producing a peptide compound or a salt thereof. The method includes the step of linking a first amino acid or the amino group of a peptide and a second amino acid or the carboxyl group of a peptide with an amide bond (linking step), wherein a condensing agent and one or more additives are present in the reaction system of the linking step, and the pKa of the additives is between 0 and 10.0, more preferably between 0 and 8.0, further preferably between 0 and 5.0, and most preferably between 1 and 5.0 (hereinafter also referred to as "Aspect 1").

[0247] In one aspect, the additive used in the connecting step has a pKa between 0 and 10.0, more preferably between 0 and 8.0, further preferably between 0 and 5.0, and most preferably between 1 and 5.0. The pKa, as used herein, can be measured using water as a solvent. The pKa can be a value already reported as a pKa when water is used as a solvent. The value measured at 25°C is used as the pKa measurement. When a pKa measurement is unavailable, the pKa can be calculated using ADMETPredictor (Simulations Plus Inc., ver8.0) and used as the pKa herein. The pKa of representative additives considered in this aspect is listed below:

[0248] HOAt (pKa = 3.28; Chem. Eur. J. 2009, 15, 9394-9403);

[0249] HOBt (pKa = 4.60; Chem. Eur. J. 2009, 15, 9394-9403);

[0250] oxyma (pKa = 4.60; Chem. Eur. J. 2009, 15, 9394-9403);

[0251] 2-Cyano-2-(hydroxyimino)acetic acid tert-butyl ester (pKa = 4.60; ACS Omega. 2022, 7, 6007-6023);

[0252] 2-Cyano-2-(hydroxyimino)acetic acid (2,2-dimethyl-1,3-dioxolane-4-yl)methyl ester (pKa = 4.5; ACS Omega. 2022, 7, 6007-6023);

[0253] 2-Amino-N-hydroxy-oxoiminoacetyl cyanide (pKa = 6.3; ACS Omega. 2022, 7, 6007-6023);

[0254] 2-(ethylamino)-N-hydroxy-2-oxoiminoacetyl cyanide (pKa = 6.3; ACSOmega.2022, 7, 6007-6023);

[0255] 2-(dimethylamino)-N-hydroxy-2-oxoiminoacetyl cyanide (pKa = 6.3; ACSOmega.2022, 7, 6007-6023);

[0256] N-hydroxy-2-oxo-2-(piperidin-1-yl)iminoacetyl cyanide (pKa = 6.3; ACSOmega.2022, 7, 6007-6023);

[0257] N-hydroxy-2-morpholino-2-oxoiminoacetyl cyanide (pKa = 6.1; ACS Omega. 2022, 7, 6007-6023);

[0258] Oxyma-B (5-(hydroxyimino)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione) (pKa =8.2; ACS Omega.2022, 7, 6007-6023);

[0259] Oxyma-T (1,3-diethyl-5-hydroxyimino-2-thio-hexahydropyrimidine-4,6-dione) (pKa = 8.2; ACS Omega. 2022, 7, 6007-6023);

[0260] Hydroxyimino-2-phenylacetonitrile (pKa = 8.2; ACS Omega. 2022, 7, 6007-6023);

[0261] Hydroxyimino-2-(4-chloro)phenylacetonitrile (pKa = 8.0; ACS Omega. 2022, 7, 6007-6023);

[0262] Hydroxy-iminopyridylformyl cyanide (pKa = 8.2; ACS Omega. 2022, 7, 6007-6023);

[0263] Hydroxyimino-2-(1-naphthyl)phenylacetonitrile (pKa = 8.2; ACS Omega. 2022, 7, 6007-6023);

[0264] Hydroxy-iminocarbonyl dicyanide (pKa = 3.8; ACS Omega. 2022, 7, 6007-6023);

[0265] 2-(hydroxyamino)malonic acid-1-ethyl ester-3-methyl ester (pKa = 7.2; ACS Omega. 2022, 7, 6007-6023);

[0266] Diethyl 2-(hydroxyamino)malonate (pKa = 7.2; ACS Omega. 2022, 7, 6007-6023);

[0267] Diisopropyl 2-(hydroxyimino)malonate (pKa = 7.2; ACS Omega. 2022, 7, 6007-6023);

[0268] HONM (5-(hydroxyimino)-2,2-dimethyl-1,3-dioxane-4,6-dione) (pKa = 6.1; ACSOmega.2022, 7, 6007-6023);

[0269] HOSu (1-hydroxypyrrolidine-2,5-dione) (pKa = 7.7; ACS Omega.2022, 7, 6007-6023);

[0270] HONB ((4S,7S)-2-hydroxy-3a,4,7,7a-tetrahydro-1H-4,7-methylene-bridged isoindole-1,3-(2H)-dione) (pKa = 7.7; ACS Omega.2022, 7, 6007-6023);

[0271] HOBI (2-Phenylacetyl-1H-benzo[d]imidazolyl-1-ol) (pKa = 7.7; ACS Omega.2022, 7,6007-6023);

[0272] 6-Cl-HOBI (6-chloro-2-phenyl-1H-benzo[d]imidazol-1-ol) (pKa = 7.1; ACSOmega.2022, 7, 6007-6023);

[0273] HODhad (3-hydroxypyridano[3,2-d]pyrimidine-4(3H)-one) (pKa = 5.8; ACS Omega. 2022, 7, 6007-6023);

[0274] 2H-Tetrazole-2-ol (pKa = 8.2; ACS Omega. 2022, 7, 6007-6023);

[0275] HOI (1-hydroxyindole-2-one) (pKa = 8.3; ACS Omega. 2022, 7, 6007-6023);

[0276] 2-(hydroxyimino)-2-(pyrazin-2-yl)acetamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0277] 2-(hydroxyimino)-2-(pyrazin-2-yl)ethyl acetate (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0278] 2-(furan-2-yl)-2-(hydroxyimino)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0279] 2-(furan-2-yl)-2-(hydroxyimino)acetamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0280] 2-(hydroxyimino)-2-(thiazolyl-2-yl)ethyl acetate (pKa = 8.7; ACS Omega. 2022, 7, 6007-6023);

[0281] 2-(hydroxyimino)-2-(thiazolyl-2-yl)acetamide (pKa = 8.7; ACS Omega. 2022, 7, 6007-6023);

[0282] 2-(hydroxyimino)-2-(pyrimidin-2-yl)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0283] 2-(hydroxyimino)-2-(pyrimidin-2-yl)acetamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0284] 2-(hydroxyimino)-2-(pyrimidin-2-yl)thioacetamide (pKa = 10.5; ACS Omega. 2022, 7, 6007-6023);

[0285] 2-(furan-2-yl)-2-(hydroxyimino)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0286] 2-(hydroxyimino)-2-(1H-pyrrolo-2-yl)acetamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0287] 2-(hydroxyimino)-2-(thiophen-2-yl)acetamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0288] 2-(hydroxyimino)-(1H-pyrrolo-2-yl)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0289] 2-(hydroxyimino)-2-(thiophen-2-yl)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0290] 2-(hydroxyimino)-2-(pyridin-2-yl)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0291] 2-(hydroxyimino)-2-(pyridin-4-yl)ethyl acetate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0292] 2-(hydroxyimino)but-3-yneamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0293] Ethyl 2-(hydroxyimino)but-3-acetylglucosinolate (pKa = 9.6; ACS Omega. 2022, 7, 6007-6023);

[0294] Ethyl 2-(hydroxyamino)-2-nitroacetate (pKa = 4.7; ACS Omega. 2022, 7, 6007-6023);

[0295] Dinitromethyl ketone oxime (pKa = 2.7; ACS Omega. 2022, 7, 6007-6023);

[0296] Nitro(phenyl) methyl ketone oxime (pKa = 7.6; ACS Omega. 2022, 7, 6007-6023);

[0297] 1-Nitro-3-phenylprop-1-one oxime (pKa = 7.4; ACS Omega. 2022, 7, 6007-6023);

[0298] 1-(hydroxyimino)-N,N-dimethyl-1-phenylmethanesulfinamide (pKa = 7.4; ACSOmega.2022, 7, 6007-6023);

[0299] 2-(hydroxyimino)-2-aminosulfonyl ethyl acetate (pKa = 5.8; ACS Omega. 2022, 7, 6007-6023);

[0300] (hydroxyimino)(methanesulfonyl)methanesulfinamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0301] 2-(hydroxyimino)-2-(methanesulfonyl)acetamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0302] 2-(hydroxyimino)-2-((trifluoromethyl)sulfonyl)ethyl acetate (pKa = 4.2; ACSOmega. 2022, 7, 6007-6023);

[0303] 2-Ethoxy-N-hydroxy-2-oxoiminoacetic acid trifluoromethanesulfonic anhydride (pKa = 7.74; ACSOmega.2022, 7, 6007-6023);

[0304] Diphenylmethyl oxime (pKa = 11.1; ACS Omega. 2022, 7, 6007-6023);

[0305] 2-((hydroxyimino)(pyridin-2-yl)methyl)-1-methylpyridin-1-onium iodide (pKa = 5.6; ACSOmega.2022, 7, 6007-6023);

[0306] 9H-fluorene-9-one oxime (pKa = 11.1; ACS Omega. 2022, 7, 6007-6023);

[0307] Anthracene-9,10-dione dioxime (pKa = 7.1; ACS Omega. 2022, 7, 6007-6023);

[0308] Pyrido[3,4-g]isoquinoline-5,10-dioxime (pKa = 5.5; ACS Omega. 2022, 7, 6007-6023);

[0309] Imidazolidin-2-one oxime (pKa = 12.5; ACS Omega. 2022, 7, 6007-6023);

[0310] 1,3-Dihydro-2H-imidazol-2-one oxime (pKa = 8.2; ACS Omega. 2022, 7, 6007-6023);

[0311] Oxazolidin-2-one oxime (pKa = 12.5; ACS Omega. 2022, 7, 6007-6023);

[0312] Oxazol-2(3H)-ketooxime (pKa = 6.6; ACS Omega. 2022, 7, 6007-6023);

[0313] 2-(hydroxyimino)malonamide (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0314] N',N'-Dihydroxy-2-(hydroxyamino)malonamide (pKa = 7.7; ACS Omega. 2022, 7, 6007-6023);

[0315] Butane-2,3-dione dioxime (pKa = 12.1; ACS Omega. 2022, 7, 6007-6023);

[0316] N'-Hydroxypyrazine-2-iminocarboxamide (pKa = 12.5; ACS Omega. 2022, 7, 6007-6023);

[0317] 3-Methyl-1,2,4-oxadiazole-5-carboxaldehyde oxime (pKa = 8.0; ACS Omega. 2022, 7, 6007-6023);

[0318] 3-(hydroxyimino)-1-phenylindoline-2-one (pKa = 9.0; ACS Omega. 2022, 7, 6007-6023);

[0319] 3-(hydroxyimino)-1-methylindolin-2-one (pKa = 9.4; ACS Omega. 2022, 7, 6007-6023);

[0320] 2-((hydroxyimino)methyl)-1-methylpyridin-1-onium (pKa = 8.0; ACS Omega. 2022, 7, 6007-6023);

[0321] 2,3,4,5,6-Pentafluorophenol (pKa = 4.9; ACS Omega. 2022, 7, 6007-6023);

[0322] 2,3,5-Trichlorophenol (pKa = 6.4; ACS Omega. 2022, 7, 6007-6023);

[0323] 4-Nitrophenol (pKa = 7.2; ACS Omega. 2022, 7, 6007-6023);

[0324] Phenol (pKa = 10.0; ACS Omega. 2022, 7, 6007-6023);

[0325] HFIP (1,1,1,3,3,3-hexafluoroprop-2-ol) (pKa = 9.3; Tetrahedron Asymmetry, 2012, 23, 1023-1027).

[0326] In one aspect, the present invention relates to a method for producing peptide compounds or salts thereof. The method includes the step of linking the amino group of a first amino acid or peptide to the carboxyl group of a second amino acid or peptide via an amide bond (the linking step), wherein a condensing agent and one or more additives are present in the reaction system of the linking step, and the additives are selected from 2-hydroxypyridine-N-oxide (HOPO), 1-hydroxy-7-azabenzotriazole (HOAt), 3,4-dihydro-3-hydroxy-4-oxo-benzotriazine (HOOBt), ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt), 2,2,3,3,3-pentafluoro-1-propanol (PfpOH), ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma), 5-(hydroxyimino)-1,3-dimethylpyrimidin-2,4,6-(1H,3H,5H)-trione (Oxyma-B), and potassium salt of ethyl (hydroxyimino)cyanoacetate (K-Oxyma). One or more of the constituent parts of the group (hereinafter also referred to as "Aspect 2").

[0327] In aspects 1 and 2, a condensing agent and one or more additives may be added to a reaction system containing a first amino acid or peptide and a second amino acid or peptide, or the first amino acid or peptide and the second amino acid or peptide may be added to a reaction system containing a condensing agent and one or more additives, respectively.

[0328] In the connecting steps of aspects 1 and 2, a condensing agent and an additive can be generated from a single reagent in the reaction system. In this respect, the single reagent can be an independent condensing agent. Furthermore, when the single reagent is an independent condensing agent, the independent condensing agent and one or more additives are each added to the reaction system as separate reagents, and the additive generated from the independent condensing agent in the reaction system and the one or more additives added to the reaction system can be different.

[0329] As used herein, "independent condensing agent" refers to a dehydration condensing agent in which a nucleophile that can form an active ester is incorporated as a leaving group. In an independent condensing agent, the oxygen of the nitrogen-oxygen bond at the nucleophilic site in the molecule binds to the dehydration condensation site to form a single compound, and the independent condensing agent possesses the properties of both a nucleophile and a dehydration condensing agent.

[0330] In one aspect, the present invention relates to a method for producing a peptide compound or a salt thereof. The method includes the step of linking a first amino acid or the amino group of a peptide and a second amino acid or the carboxyl group of a peptide with an amide bond (a linking step), wherein a separate condensing agent and one or more additives are used in the linking step, and the pKa of the additives is between 0 and 10.0, more preferably between 0 and 8.0, further preferably between 0 and 5.0, and most preferably between 1 and 5.0 (hereinafter also referred to as "Aspect 3").

[0331] In one aspect, the present invention relates to a method for producing peptide compounds or salts thereof. The method includes the step of linking the amino group of a first amino acid or peptide to the carboxyl group of a second amino acid or peptide using an amide bond (the linking step), wherein a separate condensing agent and one or more additives are used in the linking step, and the additives are selected from 2-hydroxypyridine-N-oxide (HOPO), 1-hydroxy-7-azabenzotriazole (HOAt), 3,4-dihydro-3-hydroxy-4-oxo-benzotriazine (HOOBt), ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt), 2,2,3,3,3-pentafluoro-1-propanol (PfpOH), ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma), 5-(hydroxyimino)-1,3-dimethylpyrimidin-2,4,6-(1H,3H,5H)-trione (Oxyma-B), N-hydroxysuccinimide (HOSu), and potassium salt of ethyl (hydroxyimino)cyanoacetate (K-Oxyma). One or more of the constituent parts of the group (hereinafter also referred to as "Aspect 4").

[0332] In one of aspects 1 to 4, the additive is selected from one or more of the group consisting of HOPO, HOAt, HOOBt, HOCt, Oxyma, Oxyma-B and HOSu.

[0333] In one of aspects 1 to 4, the additive is selected from the group consisting of HOPO, HOAt, HOOBt, HOCt, Oxyma, Oxyma-B and HOSu.

[0334] In aspects 3 and 4, the independent condensing agent has a structure in the molecule represented by any of the following formulas (1) to (4):

[0335] [Formula 8]

[0336]

[0337] [Formula 9]

[0338]

[0339] [Formula 10]

[0340]

[0341] Where R 4 For CH or N,

[0342] [Equation 11]

[0343] .

[0344] In aspects 3 and 4, the independent condensing agent has a structure in the molecule represented by any of the following formulas (5) to (7):

[0345] [Equation 12]

[0346]

[0347] [Equation 13]

[0348]

[0349] [Formula 14]

[0350] .

[0351] In aspects 3 and 4, specific examples of independent condensing agents include 2-cyano-2-((dimethylimino)(morpholinyl)methyloxime)ethyl acetate hexafluorophosphate (COMU), 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), O-[(ethoxycarbonyl)cyanomethyleneamino]-N,N,N',N'-tetramethylureonium hexafluorophosphate (HOTU), O-(3 The following compounds are preferred: 4-dihydro-4-oxo-1,2,3-benzotriazine-3-yl)-N,N,N',N'-tetramethylureon tetrafluoroborate (TDBTU), 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazine-4(3H)-one (DEPBT), O-[2-oxo-1(2H)-pyridyl]-N,N,N',N'-tetramethylureon tetrafluoroborate (TPTU), 2-bromo-1-ethylpyridinium tetrafluoroborate (BEP), and salicylamino-2-benzylthiophenol (Ph2CP). COMU, HATU, HOTU, DEPBT, TPTU, and TDBTU are preferred, and COMU, HATU, HOTU, DEPBT, and TDBTU are further preferred.

[0352] In one of aspects 1 to 4, the condensing agent is used in an amount of 0.5 to 5.0 molar equivalents relative to the first amino acid or peptide, more preferably in an amount of 1.0 to 5.0 molar equivalents, further preferably in an amount of 1.0 to 3.0 molar equivalents, and most preferably in an amount of 2.0 to 3.0 molar equivalents.

[0353] In certain aspects of aspects 3 and 4, the independent condensing agent is at least one selected from the group consisting of COMU, HATU, HOTU, DEPBT and TDBTU, and the additive is HOPO.

[0354] In one of aspects 1 to 3, the additive is used in an amount of 0.1 to 5.0 molar equivalents relative to the first amino acid or peptide, more preferably in an amount of 0.1 to 3.0 molar equivalents, further preferably in an amount of 0.3 to 2.6 molar equivalents, and most preferably in an amount of 0.5 to 2.0 molar equivalents.

[0355] In one aspect, the linking step can be carried out, for example, by stirring the reaction mixture for 10 minutes to 24 hours at a reaction temperature of -50°C to 30°C, preferably -20°C to 20°C, more preferably -18°C to 20°C, and most preferably 0°C to 15°C.

[0356] Another known method for separating peptide components from other unwanted components is by selectively dissolving only the peptide component bound to the dissolved tag in a specific phase, along with liquid-phase separation (hereinafter referred to as the "liquid-phase tagging method"). According to this method, unwanted components can be separated without solidification, which can accelerate and simplify the reaction process. In particular, examples of liquid-phase tagging methods using hydrophobic tags include those described in Y. Okada, H. Suzuki, T. Nakae, S. Fujita, H. Abe, K. Nagano, T. Yamada, N. Ebata, S. Kim and K. Chiba, Tag-Assisted Liquid-Phase Peptide Synthesis Using HydrophobicBenzyl Alcohols As Supports, J. Org.Chem., 2013, 78, 320-327, or S. Yano et al., Molecules 2021, 26 (12), 3497.

[0357] In one aspect, the linking step can be performed in either solid-phase or liquid-phase synthesis, but is preferably performed in liquid-phase synthesis. When the linking step is performed in liquid-phase synthesis, the liquid-phase synthesis can be carried out in an organic solvent, and a liquid-phase labeling method can be used.

[0358] In one aspect, specific examples of the organic solvent used in the connecting step include acetonitrile, isopropyl acetate, ethyl acetate, butyl acetate, methyl tert-butyl ether, diethyl ether, dichloromethane, tetrahydrofuran, 2-methyltetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, toluene, hexane, or mixtures thereof. Preferably, at least one solvent is selected from the group consisting of acetonitrile, isopropyl acetate, methyl tert-butyl ether, dichloromethane, 2-methyltetrahydrofuran, N,N-dimethylformamide, and toluene or mixtures thereof, and more preferably, at least one solvent is selected from the group consisting of acetonitrile, isopropyl acetate, and 2-methyltetrahydrofuran or mixtures thereof. As a mixed solvent, a mixture of isopropyl acetate and methyl tert-butyl ether or a mixture of isopropyl acetate and acetonitrile is preferred.

[0359] In one aspect, an alkali is used in the joining step.

[0360] In one aspect, the base used in the joining step has a pKa of 15.0 or less, preferably 13.0 or less, more preferably 11.5 or less for the conjugate acid. In one aspect, the base used in the joining step has a pKa of 0 or more, preferably 3 or more, more preferably 5 or more for the conjugate acid. In one aspect, the base used in the joining step has a pKa of between 0 and 15.0, preferably between 0 and 11.5, more preferably between 3 and 11.5, further preferably between 5 and 11.5, and most preferably between 6 and 11.5 for the conjugate acid. The pKa as used herein can be measured using water as a solvent. The pKa measured at 25°C is used as the measurement value. When a measured pKa value is unavailable, the pKa can be calculated using ADMETPredictor (Simulations Plus Inc., ver8.0) and used as the pKa in this paper. The pKa of representative reagents is listed below:

[0361] The conjugate acid of DBU (pKa = 11.9; R. Srivastava, J. Mol. Catal. A: Chem. 264(2007) 146-152);

[0362] The conjugate acid of piperidine (pKa = 11.22; Hall, HK, Jr. JAmChem. Soc. 1957, 79, 5441);

[0363] The conjugate acid of triethylamine (pKa = 10.65; Hall, HK, Jr. JAmChem. Soc. 1957, 79, 5441);

[0364] The conjugate acid of diisopropylethylamine (pKa = 11.44; Chemical and Pharmaceutical Bulletin, 1995, 43, 1872-1877);

[0365] The conjugate acid of 2,4,6-trimethylpyridine (pKa = 7.48; Clarke, K., Rothwell, KJChem. Soc. 1960, 1885);

[0366] The conjugate acid of 2,6-dimethylpyridine (pKa = 6.77; Clarke, K., Rothwell, KJ Chem.Soc. 1960, 1885);

[0367] The conjugate acid of N-methylmorpholine (pKa = 7.38; Analytical Sciences, 1996, Vol. 12)

[0368] The conjugate acid of pyridine (pKa = 5.21; DHRipin, DAEvans, pKa's of NitrogenAcids, [online],);

[0369] HCl (pKa = -8.0; DHRipin, DAEvans, pKa's of Inorganic and Oxo-Acids, [Online], [Searched December 5, 2017], Internet)<URL:http: / / evans.rc.fas.harvard.edu / pdf / evans_pKa_table.pdf> );

[0370] HFIP (1,1,1,3,3,3-hexafluoroprop-2-ol) (pKa = 9.3; Tetrahedron Asymmetry, 2012, 23, 1023-1027).

[0371] In one aspect, the base used in the linking step is an organic base. Examples of organic bases include dicyclohexylmethylamine, diisopropylethylamine, triethylamine, N-methylmorpholine, 4-N,N-dimethylaminopyridine, 2,6-dimethylpyridine, and 2,4,6-trimethylpyridine. The base used in the linking step is preferably at least one selected from the group consisting of dicyclohexylmethylamine, diisopropylethylamine, triethylamine, 2,6-dimethylpyridine, 2,4,6-trimethylpyridine, and N-methylmorpholine, more preferably dicyclohexylmethylamine or diisopropylethylamine.

[0372] As used herein, "first amino acid" and "second amino acid" are terms used only to distinguish the reaction sites between amino acids that are the substrates in the linking step. Specifically, "first amino acid" refers to an amino acid in which the amino group is the reaction site, and "second amino acid" refers to an amino acid in which the carboxyl group is the reaction site.

[0373] In one aspect, the first amino acid or peptide is a peptide containing two or more amino acid residues.

[0374] In one aspect, the amino group of the first amino acid or peptide is given by the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It is a straight-chain C1-C6 alkyl, a branched C3-C6 alkyl, or a C3-C8 cycloalkyl. In certain aspects, the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 - represents an amino group, where R 6 It is a hydrogen atom, and R 7 It is a hydrogen atom or a straight-chain C1-C4 alkyl group. In certain respects, the amino group of the first amino acid or peptide is of the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom, a methyl group, or an ethyl group. In certain respects, the amino group of the first amino acid or peptide is formed by the formula: -NR 6 R 7 - represents an amino group, where R 6 It is a hydrogen atom, and R 7 It can be a hydrogen atom or a methyl group. In certain respects, the amino group of the first amino acid or peptide is defined by the formula: -NR 6 R 7 The amino group represented by R 6 It is a hydrogen atom, and R 7 It is a methyl group.

[0375] In certain aspects, the carboxyl group of the first amino acid or peptide is optionally protected with a protecting group. Any protecting group known in the art can be used as the protecting group of the carboxyl group, as long as it does not reduce the solubility of the peptide in the solvent. Specific examples of such protecting groups for the carboxyl group include methyl, ethyl, tert-butyl, triphenylmethyl, cumyl, benzyl, and allyl, with tert-butyl being preferred.

[0376] In one respect, the second amino acid or peptide is a peptide containing two or more amino acid residues.

[0377] In one aspect, the α-carbon of the carboxyl group of the second amino acid or peptide is optionally substituted. In one aspect, the α-carbon of the carboxyl group of the second amino acid or peptide is of the formula: -CR 8 R 9 - indicates that R 8 and R 9 The same or different and each being a hydrogen atom, optionally substituted straight-chain C1-C4 alkyl, optionally substituted branched C3-C6 alkyl, optionally substituted C1-C4 alkoxy-C1-C2 alkyl, straight-chain C2-C6 alkenyl, optionally substituted phenyl C1-C2 alkyl or optionally substituted 5- to 6-membered heteroaryl C1-C2 alkyl.

[0378] When R 1 or R 2 When the alkyl group is branched C3-C6, the branched C3-C6 alkyl group may optionally be replaced with one or more halogens.

[0379] When R 1 or R 2 When it is a phenyl-C1-C2 alkyl group, the phenyl-C1-C2 alkyl group may optionally be replaced by one or more of the group consisting of methyl, ethyl, propyl, halogen, methoxy, ethoxy and trifluoromethyl.

[0380] When R 1 or R 2 When the alkyl group is a 5- or 6-membered heteroaryl-C1-C2 alkyl group, the 5- or 6-membered heteroaryl-C1-C2 alkyl group may optionally be replaced by one or more of the group consisting of methyl, ethyl, propyl, halogen, methoxy, ethoxy and trifluoromethyl.

[0381] In a particular aspect, the α-carbon of the carboxyl group of the second amino acid or peptide is represented by the formula: -CR 8 R 9 - indicates that R 8 and R 9They may be the same or different and each is a hydrogen atom, a straight-chain C1-C3 alkyl group, an isopropyl group, a 1-methylpropyl group, a 2-methylpropyl group, a tert-butoxymethyl group, a 2-propenyl group, or an optionally substituted benzyl group.

[0382] When R 1 or R 2 When benzyl, the benzyl or phenethyl group may optionally be replaced by one or more of the group consisting of fluorine, methyl, ethyl, methoxy, ethoxy and trifluoromethyl.

[0383] In a particular aspect, the α-carbon of the carboxyl group of the second amino acid or peptide is represented by the formula: -CR 8 R 9 - indicates that R 8 It is a hydrogen atom, and R 2 It can be a hydrogen atom, methyl, 1-methylpropyl, 2-methylpropyl, tert-butoxymethyl, 2-propenyl, benzyl, p-methylbenzyl, or p-fluorobenzyl.

[0384] In one aspect, the amino group containing the nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is defined by the formula: -NR 5 - indicates that R 5 It can be a hydrogen atom, a straight-chain C1-C6 alkyl group, a branched C3-C6 alkyl group, or a C3-C8 cycloalkyl group.

[0385] In a particular aspect, the amino group containing a nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is defined by the formula: -NR 5 - indicates that R 3 It consists of hydrogen atoms or straight-chain C1-C4 alkyl groups.

[0386] In a particular aspect, the amino group containing a nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is defined by the formula: -NR 5 - indicates that R 3 It can be a hydrogen atom, a methyl group, or an ethyl group.

[0387] In a particular aspect, the amino group containing the nitrogen atom at the β-position of the carboxyl group of the second amino acid or peptide is defined by the formula: -NR 5 - indicates that R 3 It can be a hydrogen atom or a methyl group.

[0388] In one aspect, the amino group of the second amino acid or peptide is optionally protected with a protecting group. Any protecting group known in the art can be used as the protecting group of the amino group, provided that it does not reduce the solubility of the peptide in the solvent. Specific examples of such protecting groups for the amino group include Cbz, p-nitrobenzyloxycarbonyl, 2-naphthylmethoxycarbonyl, diphenylmethoxycarbonyl, 9-anthraylmethoxycarbonyl, Teoc, Fmoc, Boc, Alloc, trifluoroacetyl, triphenylmethyl, and methoxycarbonyl, and wherein Cbz, Teoc, Fmoc, Boc, Alloc, and trifluoroacetyl are preferred.

[0389] In one aspect, the peptide compound or its salt produced by the method of the present invention contains 8 to 20 residues, preferably 11 to 14 residues, more preferably 11 to 13 residues, and most preferably 11 residues of amino acid residues.

[0390] In one aspect, the peptide compound or its salt produced by the method of the present invention may contain at least one, at least two, at least three, at least four, or at least five non-natural amino acid residues. In a particular aspect, the non-natural amino acid residues contained in the peptide compound or its salt produced by the method of the present invention are N-methyl amino acid residues.

[0391] In one aspect, the peptide compound produced by the method of the present invention can be a linear peptide compound. In another aspect, the peptide compound produced by the method of the present invention can be a cyclic peptide compound. In one aspect, the linear or cyclic peptide compound may include a cyclic structure (cyclic portion) as its basic structure. Specific examples of such cyclic structures include those cyclic structures in which the side chain of one amino acid residue is linked to the side chain of another amino acid residue, those cyclic structures in which an N-substituent of one amino acid residue is linked to the side chain of another amino acid residue, and those cyclic structures in which an N-substituent of one amino acid residue is linked to an N-substituent of another amino acid residue. The two amino acid residues involved in the linkage of the cyclic structure may be adjacent, or any number of amino acid residues, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 amino acid residues may be present therebetween. Examples of ring sizes formed by ring structures include, but are not intended to be particularly limited to, 4-membered rings, 5-membered rings, 6-membered rings, 7-membered rings, 8-membered rings, 9-membered rings, 10-membered rings, 11-membered rings, 12-membered rings, 13-membered rings, 14-membered rings, 15-membered rings, 16-membered rings, 17-membered rings, 18-membered rings, 19-membered rings, 20-membered rings, 21-membered rings, 22-membered rings, 23-membered rings, 24-membered rings, 25-membered rings, 26-membered rings, 27-membered rings, 28-membered rings, 29-membered rings, 30-membered rings, 31-membered rings, 32-membered rings, 33-membered rings, 34-membered rings, and 35-membered rings. Preferably, the rings formed by the cyclic structure are 5-membered, 6-membered, 7-membered, 8-membered, 9-membered, 10-membered, 11-membered, 12-membered, 13-membered, 14-membered, 15-membered, 16-membered, 17-membered, 18-membered, 19-membered, or 20-membered rings; more preferably, they are 10-membered, 11-membered, 12-membered, 13-membered, 14-membered, 15-membered, 16-membered, 17-membered, or 18-membered rings; and most preferably, they are 11-membered, 12-membered, 13-membered, or 14-membered rings. When the cyclic structure is present in the peptide compound, the number of cyclic structures is not limited, but the presence of one, two, three, four, or five cyclic structures is preferred.

[0392] In one aspect, the peptide compound or salt thereof produced by the method of the present invention may contain a cyclic moiety consisting of 4 or more, 6 or more, 8 or more, or 11 or more amino acid residues. In one embodiment, the peptide compound or salt thereof produced by the method of the present invention is a cyclic peptide compound or salt thereof, which consists of a cyclic moiety consisting of 4 to 14, preferably 6 to 14, more preferably 8 to 14, and most preferably 11 to 14 amino acid residues. In one embodiment, the peptide compound or salt thereof produced by the method of the present invention is a cyclic peptide compound or salt thereof, which consists of a cyclic moiety consisting of 11 amino acid residues. In these aspects, the cyclic moiety contains an amide bond at positions 1, 2, 3, 4, 5, 6, or 7, which links the amino group of the first amino acid or peptide to the carboxyl group of the second amino acid or peptide.

[0393] In one embodiment, the method of the present invention may further include a step of removing / deprotecting the protecting groups of the second amino acid or the amino or carboxyl group of the peptide and / or the first amino acid or the amino or carboxyl group of the peptide in the peptide compound obtained in the ligation step, immediately before or after the ligation step and / or during the ligation step (deprotection step). The deprotection step can be performed using methods known in the art, such as those described in "Greene's Protective Groups in Organic Synthesis, Fifth Edition, 2014" using the reagents and conditions described therein.

[0394] In one aspect, the deprotection step of the protecting group of an amino group can be carried out by contact hydrogenation, for example when the protecting group is Cbz, p-nitrobenzyloxycarbonyl, 2-naphthylmethoxycarbonyl, diphenylmethoxycarbonyl, or 9-anthraylmethoxycarbonyl. For contact hydrogenation, any catalyst known in the art can be used. Specific examples of catalysts include Pd / C, Pd(OH)2 / C, and PtO2, with Pd / C being preferred.

[0395] In one aspect, reagents such as TBAF, LiBH4, piperidine, trifluoroacetic acid, or methanesulfonic acid can be used for the deprotection step of the protecting group of the amino group, for example when the protecting group is Teoc, Fmoc, Boc, Alloc, or trifluoroacetyl.

[0396] In one aspect, the deprotection step of the carboxyl protecting group can be carried out under acidic conditions in the presence of a deprotecting agent, for example when the protecting group is methyl, ethyl, tert-butyl, triphenylmethyl, cumyl, benzyl, or allyl.

[0397] In one aspect, the method of the present invention may further include the step of linking / condensing a third amino acid or peptide to the peptide compound obtained in the linking or deprotection step (linking step A). ​​That is, the method of the present invention may include repeating the linking step two or more times.

[0398] In one aspect, the method of the present invention may further include a step of linking / condensing the amino and carboxyl groups in the peptide compound obtained in the linking or deprotection step (linking step B). In this case, the peptide compound obtained in linking step B is a cyclic peptide compound.

[0399] In one aspect, steps A and B can be performed, for example, in the presence or absence of a condensing agent. Examples of condensing agents include T3P, EDCI, HATU, COMU, BEP, PyBOP, DMT-MM, and PyOxim.

[0400] In one aspect, the method of the invention is carried out using a flow reaction apparatus. As used herein, a “flow reaction apparatus” means an apparatus that continuously supplies raw materials to a tubular reaction vessel, mixes the raw materials, and reacts the raw materials to produce a target compound. The flow reaction apparatus may be a commercially available flow reaction apparatus (e.g., the Africa Flow Chemistry System or the Asia Flow Chemistry System manufactured by Syrris), or it may be an apparatus combining a tubular reaction vessel and an injection pump.

[0401] peptide compounds

[0402] In one aspect, the present invention relates to a peptide compound or a salt thereof produced by the above-described "method for producing a cyclic peptide compound". In another aspect, the present invention relates to a pharmaceutical composition comprising a peptide compound or a salt thereof produced by the above-described "method for producing a cyclic peptide compound".

[0403] All references cited in this paper, including the following patent applications and publications, are incorporated herein by reference in their entirety: International Publication No. WO 2013 / 100132; International Publication No. WO 2018 / 225851; International Publication No. WO 2018 / 225864; International Publication No. WO 2019 / 117274; International Publication No. WO 2020 / 111238; International Publication No. WO 202012 / 2182; International Publication No. WO 2021 / 075478; International Publication No. WO 2021 / 090856; International Publication No. WO 2021132545; International Publication No. WO 2021246471; International Publication No. WO 2022 / 097540; International Publication No. WO 2022 / 138891; International Publication No. WO 20221 / 45444; International Publication No. WO 2022 / 234864; International Publication No. WO 2023 / 127869.

[0404] Example

[0405] The invention will be further described through the following examples, but the invention is not limited to the examples. In addition to those specifically described, starting materials, starting raw materials, solvents, and reagents are obtained from commercial suppliers or synthesized using known methods. In the examples, "OxymaPure" is the trade name of a product obtained from a commercial supplier of ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma).

[0406] ¹H-NMR spectra were measured using a JNM-ECZ 500 nuclear magnetic resonance apparatus (manufactured by JEOL Ltd.). The chemical shift of tetramethylsilane, used as an internal standard, was set to 0 ppm, and the deuterium-locked signal from the sample solvent was referenced. The chemical shift of the signal from the analyte is expressed in ppm. Signal splits are abbreviated as follows: s = singlet, brs = broad singlet, d = doublet, t = triplet, q = quadruplet, dd = doublet, m = multiplet. The width of the signal split is expressed as the J value (Hz). The integral value of the signal is calculated based on the ratio of the area intensity of each signal.

[0407] HPLC analysis was performed using an H-Class system manufactured by Waters Corporation, with measurements taken at 210 nm using a PDA detector. The reactivity, selectivity, and purity of each substrate used in the examples were evaluated using the analytical methods shown in Table 1 below. LCMS analysis was performed using either an SQD2 or QDa detector.

[0408] [Table 1]

[0409]

[0410] Unless otherwise specified in the experimental section, HPLC samples should be prepared as follows.

[0411] Condensation step: Dissolve 3 to 10 μL of the reaction mixture in MeCN (1.0 mL) and aziridine or 1-propylamine (0.1 mL).

[0412] The conversion and diastereomeric ratio of the condensation reaction were calculated using the HPLC area values ​​of each component in the reaction mixture according to the following formula. The substrate in the formula refers to the substrate with the lower molar packing amount among the two condensation substrates.

[0413] Conversion rate = [(Desired product + Epimer) / (Substrate + Desired product + Epimer)] x 100

[0414] Diasteresome Ratio = Desired Product / Epimer

[0415] (Example 1) Evaluation of the effects of multiple additives on the addition of independent condensing agent (DEPBT)

[0416] [Formula 15]

[0417]

[0418] Under each of the conditions shown in Table 2, DEPBT (61.5 mg, 0.206 mmol, 2.0 equivalents) and the additive (0.051 mmol, 0.5 equivalents) were added to a test tube equipped with a stirrer, and the mixture was cooled to 10 °C. A solution of Cbz-MeLeu-MePhe-OH in IPAC (concentrations of 160.0 mg / mL, 0.300 mL, 48.0 mg, 0.109 mmol, 1.1 equivalents), a solution of H-MeGly(cPent)-MeAsp(OtBu)-NMe2 in 2-MeTHF (concentrations of 76.8 mg / mL, 0.500 mL, 38.4 mg, 0.104 mmol, 1.0 equivalents), and DIPEA (90.0 μL, 0.514 mmol, 5.0 equivalents) were added sequentially. The reaction mixture was stirred for 9 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0419] Measurement method: HPLC method A

[0420] Retention time: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: 6.7 min, desired product: 18.6 min, epimer: 19.0 min

[0421] Mass spectrometry: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: m / z 370.30 ([M+H] + ), Required product: m / z 747.45 ([M-NMe2] + Epimer: m / z 747.49 ([M-NMe2]) + )

[0422] [Table 2]

[0423]

[0424] As shown in Table 2, the diastereomeric ratio was improved by adding multiple additives to the independent condensing agent DEPBT.

[0425] (Example 2) Evaluation of the effects of multiple additives on independent condensing agents (COMU)

[0426] [Formula 16]

[0427]

[0428] Under each of the conditions shown in Table 3, Cbz-MeLeu-MeAla-OH (27.1 mg, 0.074 mmol, 1.1 equivalents), additive (0.135 mmol, 2.0 equivalents), MeCN (0.152 mL), a solution of H-MeGly(cPent)-MeAsp(OtBu)-NMe2 in MeCN (concentrations 170.0 mg / mL, 0.147 mL, 25.0 mg, 0.068 mmol, 1.0 equivalents), and DIPEA (81.5 μL, 0.474 mmol, 7.0 equivalents) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to 10 °C with stirring. COMU (58.0 mg, 0.135 mmol, 2.0 equivalents) was added to the reaction mixture, and the mixture was stirred for 5 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated. Measurement method: HPLC method A

[0429] Retention times: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: 5.5 min, desired product: 16.1 min, epimer: 16.3 min

[0430] Mass spectrometry: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: m / z 370.26 ([M+H] + ), Required product: m / z 738.49 ([M+Na] + Epimer: m / z 738.48 ([M+Na]) + )

[0431] [Table 3]

[0432]

[0433] As shown in Table 3, the diastereomeric ratio was improved by adding multiple additives to the independent condensing agent COMU. The effect of adding HOPO was particularly high.

[0434] (Example 3) Evaluation of the effects of HOPO on the addition of multiple independent condensing agents

[0435] [Equation 17]

[0436]

[0437] Under each of the conditions shown in Table 4, Cbz-MeLeu-MeAla-OH (27.1 mg, 0.074 mmol, 1.1 equivalents), HOPO (15.0 mg, 0.135 mmol, 2.0 equivalents), 2-MeTHF (0.152 mL), a solution of H-MeGly(cPent)-MeAsp(OtBu)-NMe2 in 2-MeTHF (concentrations: 170.0 mg / mL, 0.147 mL, 25.0 mg, 0.068 mmol, 1.0 equivalents), and DIPEA (81.5 μL, 0.474 mmol, 7.0 equivalents) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to 10 °C with stirring. An independent condensing agent (0.135 mmol, 2.0 equivalents) was added to the reaction mixture, and the mixture was stirred for 5 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0438] Measurement method: HPLC method A

[0439] Retention times: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: 5.5 min, desired product: 16.1 min, epimer: 16.3 min

[0440] Mass spectrometry: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: m / z 370.29 ([M+H] + ), Required product: m / z 738.55 ([M+Na] + Epimer: m / z 738.49 ([M+Na]) + )

[0441] [Table 4]

[0442]

[0443] As shown in Table 4, the conversion rate and diastereomeric ratio were improved by adding HOPO to a variety of independent condensing agents.

[0444] (Example 4) Evaluation of the effects of various additives on the addition of HOPO-containing independent condensing agent (TPTU)

[0445] [Formula 18]

[0446]

[0447] Under each of the conditions shown in Table 5, Cbz-MeLeu-MeAla-OH (27.1 mg, 0.074 mmol, 1.1 equivalents), additive (0.068 mmol, 1.0 equivalents), 2-MeTHF (0.152 mL), a solution of H-MeGly(cPent)-MeAsp(OtBu)-NMe2 in 2-MeTHF (concentrations: 170.0 mg / mL, 0.147 mL, 25.0 mg, 0.068 mmol, 1.0 equivalents), and DIPEA (81.5 μL, 0.474 mmol, 7.0 equivalents) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to 10 °C with stirring. TPTU (40.2 mg, 0.135 mmol, 1.1 equivalents) was added to the reaction mixture, and the mixture was stirred for 5 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0448] Measurement method: HPLC method A

[0449] Retention times: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: 5.5 min, desired product: 16.1 min, epimer: 16.3 min

[0450] Mass spectrometry: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: m / z 370.27 ([M+H] + ), Required product: m / z 738.47 ([M+Na] + Epimer: m / z 738.48 ([M+Na]) + )

[0451] [Table 5]

[0452]

[0453] As shown in Table 5, the conversion rate and diastereomeric ratio were improved by adding a variety of additives to the HOPO-containing independent condensing agent.

[0454] (Example 5) Assessment of Alkali

[0455] [Formula 19]

[0456]

[0457] Under each of the conditions shown in Table 6, Cbz-MeLeu-MeAla-OH (27.1 mg, 0.074 mmol, 1.1 equivalents), HOPO (15.0 mg, 0.135 mmol, 2.0 equivalents), MeCN (0.152 mL), a solution of H-MeGly(cPent)-MeAsp(OtBu)-NMe2 in MeCN (concentrations 170.0 mg / mL, 0.147 mL, 25.0 mg, 0.068 mmol, 1.0 equivalents), and a base (0.474 mmol, 7.0 equivalents) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to 10 °C with stirring. COMU (58.0 mg, 0.135 mmol, 2.0 equivalents) was added to the reaction mixture, and the mixture was stirred for 5 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0458] Measurement method: HPLC method A

[0459] Retention times: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: 5.5 min, desired product: 16.1 min, epimer: 16.3 min

[0460] Mass spectrometry: H-MeGly(cPent)-MeAsp(OtBu)-NMe2: m / z 370.28 ([M+H] +), Required product: m / z 738.49 ([M+Na] + Epimer: m / z 738.49 ([M+Na]) + )

[0461] [Table 6]

[0462]

[0463] As shown in Table 6, particularly high conversion rates and diastereomeric ratios were obtained from conditions using dicyclohexylmethylamine, DIPEA, or TEA.

[0464] (Example 6) Solvent Evaluation

[0465] [Formula 20]

[0466]

[0467] Under each of the conditions shown in Table 7, Cbz-MeLeu-MeAla-OH (23.9 mg, 0.066 mmol, 1.1 equivalents), HOPO (15.0 mg, 0.135 mmol, 2.0 equivalents), H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (30.0 mg, 0.060 mmol, 1.0 equivalents), solvent (0.300 mL), and DIPEA (0.418 mmol, 7.0 equivalents) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to 10 °C with stirring. COMU (51.1 mg, 0.119 mmol, 2.0 equivalents) was added to the reaction mixture, and the mixture was stirred for 2 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0468] Measurement method: HPLC method A

[0469] Retention time: H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: 7.9 min, desired product: 15.6 min, epimer: 15.9 min

[0470] Mass spectrum: H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: m / z 503.36 ([M+H] + ), Required product: m / z 849.63 ([M+H] + Epimer: m / z 849.56 ([M+H])+ )

[0471] [Table 7]

[0472]

[0473] As shown in Table 7, the highest conversion and diastereomeric ratios were obtained from conditions using highly polar solvents such as MeCN and DMF.

[0474] (Example 7) Condensation reaction of Cbz-MeAla-MeLeu-OH with H-MeGly(nPr)-Ile-Pro-OtBu

[0475] [Equation 21]

[0476]

[0477] Condition A: Experiments using HATU and HOPO

[0478] H-MeGly(nPr)-Ile-Pro-OtBu (24.1 mg, 0.061 mmol), HOPO (13.5 mg, 0.121 mmol), MeCN (0.200 mL), a solution of Cbz-MeAla-MeLeu-OH in 2-MeTHF (concentrations 170.0 mg / mL, 0.160 mL, 27.0 mg, 0.073 mmol), and Cy2NMe (90.0 μL, 0.424 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 10 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0479] Condition B: Comparative experiments using only HATU

[0480] H-MeGly(nPr)-Ile-Pro-OtBu (24.1 mg, 0.061 mmol), MeCN (0.200 mL), a solution of Cbz-MeAla-MeLeu-OH in 2-MeTHF (concentrations 170.0 mg / mL, 0.160 mL, 27.0 mg, 0.073 mmol), and Cy2NMe (90.0 μL, 0.424 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 10 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0481] Measurement method: HPLC method A

[0482] Retention times: H-MeGly(nPr)-Ile-Pro-OtBu: 8.8 min, desired product: 18.1 min, epimer: 18.2 min

[0483] Mass spectrometry: H-MeGly(nPr)-Ile-Pro-OtBu: m / z 398.87 ([M+H] + ), Required product: m / z 745.03 ([M+H] + Epimer: m / z 745.03 ([M+H]) + )

[0484] [Table 8]

[0485]

[0486] As shown in Table 8, it was found that Condition A, which uses both HATU and HOPO, has a higher diastereomeric ratio compared to Condition B, which uses only HATU as a condensing agent.

[0487] (Example 8) Condensation reaction of Cbz-Leu-MePhe-OH with H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu

[0488] [Equation 22]

[0489]

[0490] Condition A: Experiments using HATU and HOPO

[0491] Cbz-Leu-MePhe-OH (31.0 mg, 0.073 mmol), H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (45.0 mg, 0.061 mmol), HOPO (13.5 mg, 0.121 mmol), MeCN (0.400 mL), and Cy2NMe (90.0 μL, 0.424 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5°C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10°C. The mixture was stirred for 10 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0492] Condition B: Comparative experiments using only HATU

[0493] Cbz-Leu-MePhe-OH (31.0 mg, 0.073 mmol), H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (45.0 mg, 0.061 mmol), MeCN (0.400 mL), and Cy2NMe (90.0 μL, 0.424 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 10 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0494] Measurement method: HPLC method A

[0495] Retention time: H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: 9.8 min, desired product: 17.5 min, epimer: 18.2 min

[0496] Mass spectrum: H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: m / z 743.61 ([M+H] + ), Required product: m / z 1007.73 ([M-Sar-OtBu] + Epimer: m / z 1007.72 ([M-Sar-OtBu]) + )

[0497] [Table 9]

[0498]

[0499] As shown in Table 9, it was found that Condition A, which used both HATU and HOPO, had a higher diastereomeric ratio compared to Condition B, which used only HATU as a condensing agent.

[0500] (Example 9) Condensation reaction of Cbz-MeLeu-MeSer(OtBu)-OH with H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu

[0501] [Equation 23]

[0502]

[0503] Condition A: Experiments using HATU and HOPO

[0504] H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (45.0 mg, 0.061 mmol), HOPO (13.5 mg, 0.121 mmol), MeCN (0.200 mL), a solution of Cbz-MeLeu-MeSer(OtBu)-OH in 2-MeTHF (concentration 166.5 mg / mL, 0.190 mL, 31.6 mg, 0.073 mmol), and Cy2NMe (90.0 μL, 0.424 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 24 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0505] Condition B: Comparative experiments using only HATU

[0506] H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (45.0 mg, 0.061 mmol), MeCN (0.200 mL), a solution of Cbz-MeLeu-MeSer(OtBu)-OH in 2-MeTHF (concentrations 166.5 mg / mL, 0.190 mL, 31.6 mg, 0.073 mmol), and Cy2NMe (90.0 μL, 0.424 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 24 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0507] Measurement method: HPLC method A

[0508] Retention time: H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: 11.2 min, desired product: 20.2 min, epimer: 21.0 min

[0509] Mass spectrum: H-MeLeu-Ile-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: m / z 744.24 ([M+H] + ), Required product: m / z 1017.27 ([M-Sar-OtBu] + Epimer: m / z 1017.22 ([M-Sar-OtBu]) + )

[0510] [Table 10]

[0511]

[0512] As shown in Table 10, it was found that Condition A, which uses both HATU and HOPO, has a higher diastereomeric ratio compared to Condition B, which uses only HATU as a condensing agent.

[0513] (Example 10) Condensation reaction of Cbz-Aze-EtPhe(4-Me)-OH with H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu

[0514] [Equation 24]

[0515]

[0516] Condition A: Experiments using HATU and HOPO

[0517] HOPO (13.5 mg, 0.121 mmol), Cbz-Aze-EtPhe(4-Me)-OH (31.0 mg, 0.073 mmol), MeCN (0.200 mL), a solution of H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu in MeCN (concentrations 200.0 mg / mL, 0.150 mL, 30.0 mg, 0.061 mmol), and Cy2NMe (90.0 μL, 0.425 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 24 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0518] Condition B: Comparative experiments using only HATU

[0519] To a test tube equipped with a stirrer, Cbz-Aze-EtPhe(4-Me)-OH (31.0 mg, 0.073 mmol), MeCN (0.200 mL), a solution of H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu in MeCN (concentrations of 200.0 mg / mL, 0.150 mL, 30.0 mg, 0.061 mmol), and Cy2NMe (90.0 μL, 0.425 mmol) were added sequentially. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 24 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0520] Measurement method: HPLC method A

[0521] Retention time: H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: 9.2 min, desired product: 17.0 min, epimer: 17.2 min

[0522] Mass spectrum: H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: m / z 503.98 ([M+H] + ), Required product: m / z 764.93 ([M-Sar-OtBu]+ Epimer: m / z 764.99 ([M-Sar-OtBu]) + )

[0523] [Table 11]

[0524]

[0525] As shown in Table 11, it was found that Condition A, which uses both HATU and HOPO, has a higher diastereomeric ratio compared to Condition B, which uses only HATU as a condensing agent.

[0526] (Example 11) Condensation reaction of Fmoc-MeAlGly-MeAlGly-OH with H-MeGly(nPr)-Ile-Pro-OtBu

[0527] [Equation 25]

[0528]

[0529] Condition A: Experiments using HATU and HOPO

[0530] H-MeGly(nPr)-Ile-Pro-OtBu (24.1 mg, 0.061 mmol), Fmoc-MeAlGly-MeAlGly-OH (33.6 mg, 0.073 mmol), HOPO (13.5 mg, 0.121 mmol), MeCN (0.400 mL), and DIPEA (73.9 μL, 0.424 mmol) were added sequentially to a stirrer-equipped test tube. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 10 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0531] Condition B: Comparative experiments using only HATU

[0532] H-MeGly(nPr)-Ile-Pro-OtBu (24.1 mg, 0.061 mmol), Fmoc-MeAlGly-MeAlGly-OH (33.6 mg, 0.073 mmol), MeCN (0.400 mL), and DIPEA (73.9 μL, 0.424 mmol) were added sequentially to a stirrer-equipped test tube. The reaction mixture was cooled to -5 °C with stirring. HATU (46.1 mg, 0.121 mmol) was added to the reaction mixture, and the temperature was raised to 10 °C. The mixture was stirred for 10 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0533] Measurement method: HPLC method A

[0534] Retention times: H-MeGly(nPr)-Ile-Pro-OtBu: 8.9 min, desired product: 19.5 min, epimer: 19.6 min

[0535] Mass spectrometry: H-MeGly(nPr)-Ile-Pro-OtBu: m / z 398.89 ([M+H] + ): Required product: m / z 865.08 ([M+Na] + Epimer: m / z 865.02 ([M+Na]) + )

[0536] [Table 12]

[0537]

[0538] As shown in Table 12, it was found that Condition A, which uses both HATU and HOPO, has a higher diastereomeric ratio compared to Condition B, which uses only HATU as a condensing agent.

[0539] (Example 12) Condensation reaction of Cbz-MeLeu-MeIle-OH with H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu

[0540] [Equation 26]

[0541]

[0542] Condition A: Experiments using HATU and HOPO

[0543] Cbz-MeLeu-MeIle-OH (39.0 mg, 0.096 mmol), H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (38.6 mg, 0.077 mmol), HOPO (17.1 mg, 0.154 mmol), MeCN (0.500 mL), and Cy2NMe (114 μL, 0.538 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5°C with stirring. HATU (58.4 mg, 0.154 mmol) was added to the reaction mixture, and the temperature was raised to 10°C. The mixture was stirred for 24 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0544] Condition B: Comparative experiments using only HATU

[0545] Cbz-MeLeu-MeIle-OH (39.0 mg, 0.096 mmol), H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu (38.6 mg, 0.077 mmol), MeCN (0.500 mL), and Cy2NMe (114 μL, 0.538 mmol) were added sequentially to a test tube equipped with a stirrer. The reaction mixture was cooled to -5°C with stirring. HATU (58.4 mg, 0.154 mmol) was added to the reaction mixture, and the temperature was raised to 10°C. The mixture was stirred for 9 hours. The reaction mixture was analyzed by HPLC, and the conversion and diastereomeric ratio were evaluated.

[0546] Measurement method: HPLC method A

[0547] Retention time: H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: 9.2 min, desired product: 18.5 min, epimer: 19.0 min

[0548] Mass spectrum: H-MeAla-Aze-EtPhe(4-Me)-Sar-OtBu: m / z 503.86 ([M+H] + ), Required product: m / z 914.10 ([M+Na] + Epimer: m / z 914.16 ([M+Na]) + )

[0549] [Table 13]

[0550]

[0551] As shown in Table 13, it was found that Condition A, which uses both HATU and HOPO, has a higher diastereomeric ratio compared to Condition B, which uses only HATU as a condensing agent.

[0552] (Synthesis of raw materials 1) Synthesis of Cbz-MeLeu-MePhe-OH

[0553] [Equation 27]

[0554]

[0555] Cbz-MePhe-OtBu (6.50 g, 17.59 mmol) was dissolved in 2-MeTHF (50 mL) and added to a pressurized reaction vessel. 5% Pd / C (3.76 g, 0.88 mmol on a Pd metal substrate) was added to the pressurized reaction vessel, and nitrogen and hydrogen purging were performed. The mixture was stirred for 6 hours under hydrogen pressure (3 to 4 atm). The reaction mixture was filtered and the Pd / C was washed with 2-MeTHF. The filtrate and wash solution were combined and concentrated under reduced pressure to obtain H-MePhe-OtBu (4.13 g, 17.55 mmol). Cbz-MeLeu-OH (4.62 g, 16.54 mmol) was added to a flask equipped with a stirrer. Add H-MePhe-OtBu solution in MeCN (0.10 g / mL, 37.0 mL, 3.70 g, 15.72 mmol) and NMM (5.2 mL, 47.20 mmol) sequentially to the flask. Add HATU (8.97 g, 23.58 mmol) to the reaction mixture and stir continuously at room temperature. Continue stirring for 1 hour and confirm the completion of the reaction by HPLC analysis. Add CPME (50.0 mL), 5% K2CO3 aqueous solution (50.0 mL), and NMI (1.25 mL, 15.72 mmol) to the reaction mixture and stir continuously for 1.5 hours. Transfer all contents of the flask to a separatory funnel and remove the aqueous layer. The organic layer was washed three times with 2.5% ammonia solution (50 mL x 3), twice with 5% NaHSO4 solution (50 mL x 2), and once with 5% Na2CO3 solution (40 mL x 1). The obtained organic layer was dried with anhydrous Na2SO4. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-MeLeu-Phe-OtBu (6.90 g, 13.89 mmol). Cbz-MeLeu-MePhe-OtBu (6.90 g, 13.89 mmol), 2-MeTHF (70 mL), and HMDS (15.0 mL, 69.50 mmol) were added to a flask equipped with a stirrer, and then TMSOTf (10.1 mL, 55.60 mmol) was added dropwise. The mixture was stirred continuously for 2 hours, and then HMDS (2.9 mL) and TMSOTf (2.5 mL) were added to the reaction mixture.The mixture was stirred continuously for another 1.5 hours, and then HMDS (6.0 mL) and TMSOTf (5.0 mL) were added to the reaction mixture. The conversion was confirmed to be 94% by HPLC analysis. The flask was cooled, and 70 mL of 5% NaHCO3 aqueous solution was added dropwise to the reaction mixture while maintaining the reaction mixture at 33°C or lower. All contents of the flask were transferred to a separatory funnel and washed with 30 mL of 5% NaHCO3 aqueous solution and 30 mL of 2-MeTHF. The organic and aqueous layers were subjected to HPLC analysis, and the organic layer was then removed. 100 mL of 2-MeTHF was added to the resulting aqueous layer, followed by gradual addition of 7.5 mL of 85% H3PO4. The aqueous layer was removed, and the mixture was washed with 50 mL of 5% NaCl aqueous solution and the resulting organic layer was concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography to obtain Cbz-MeLeu-MePhe-OH (5.00 g, 11.35 mmol).

[0556] Yield: 72% (starting from H-MePhe-OtBu through 2 steps)

[0557] Purity: 100%

[0558] Measurement method: HPLC method A, retention time: 13.9 min

[0559] Mass spectrometry: m / z 441.78 ([M+H]) + )

[0560] (Synthesis of raw materials 2) Synthesis of Cbz-MeLeu-MeAla-OH

[0561] [Equation 28]

[0562]

[0563] Add Cbz-MeLeu-OH (10.50 g, 37.59 mmol), H-MeAla-OtBu·HCl (7.00 g, 35.77 mmol), 2-MeTHF (70 mL), MeCN (50 mL), and NMM (11.8 mL, 107 mmol) to a flask equipped with a stirrer. Cool the flask, add HATU (20.40 g, 53.65 mmol) to the reaction mixture while maintaining the reaction mixture at 30°C or lower, and continuously stir the mixture at room temperature. Continue stirring for 3 hours and confirm the completion of the reaction by HPLC analysis. Add IPAC (50 mL), 5% Na₂CO₃ aqueous solution (70 mL), and NMI (2.84 mL, 35.81 mmol) to the reaction mixture, and continuously stir the mixture for 30 minutes. Transfer all contents of the flask to a separatory funnel and remove the aqueous layer. The organic layer was washed three times with 2.5% ammonia solution (50 mL x 3), twice with 5% NaHSO4 solution (50 mL x 2), once with 5% Na2CO3 solution (50 mL), and once with 10% NaCl solution (50 mL). The obtained organic layer was dried over anhydrous Na2SO4, the desiccant was filtered off, and the filtrate was concentrated under reduced pressure to obtain Cbz-MeLeu-MeAla-OtBu (14.35 g, 34.12 mmol). 2-MeTHF (140 mL) and HMDS (49.9 mL, 238.9 mmol) were added to the obtained concentrate, followed by dropwise addition of TMSOTf (37.7 mL, 204.7 mmol). Stirring was continued for 3.5 hours, and the completion of the reaction was confirmed by HPLC analysis. Cool the flask and add 70 mL of 5% Na₂CO₃ aqueous solution dropwise to the reaction mixture while maintaining the reaction mixture at 30°C or lower. Transfer all contents of the flask to a separating funnel, add 30 mL of 2-MeTHF and 30 mL of 5% Na₂CO₃ aqueous solution, and remove the aqueous layer. Add 100 mL of 2-MeTHF, followed by gradual addition of 15 mL of 85% H₃PO₄. Remove the aqueous layer, wash with 50 mL of 10% NaCl aqueous solution, and concentrate the organic layer under reduced pressure. Purify the concentrate by silica gel column chromatography to obtain Cbz-MeLeu-MeAla-OH (9.74 g).

[0564] Yield: 75% (after 2 steps)

[0565] Purity: 98.2%

[0566] Measurement method: HPLC method A, retention time: 11.3 min

[0567] Mass spectrometry: m / z 365.08 ([M+H]) + )

[0568] (Analytical Standard Synthesis 1) Synthesis of Cbz-MeLeu-D-MeAla-OH

[0569] [Equation 29]

[0570]

[0571] Add Cbz-MeLeu-OH (2.25 g, 8.05 mmol), H-MeAla-OtBu·HCl (1.50 g, 7.67 mmol), MeCN (20 mL), and NMM (2.53 mL, 23.0 mmol) to a flask equipped with a stirrer. Cool the flask, add HATU (4.37 g, 11.5 mmol) to the reaction mixture while maintaining the reaction mixture at 30°C or lower, and continuously stir the mixture at room temperature. Continue stirring for 6 hours and confirm the completion of the reaction by HPLC analysis. Add IPAC (20 mL), 5% Na₂CO₃ aqueous solution (20 mL), and NMI (0.608 mL, 7.67 mmol) to the reaction mixture, and continuously stir the mixture for 30 minutes. Transfer all contents of the flask to a separatory funnel and remove the aqueous layer. The organic layer was washed three times with 2.5% ammonia solution (15 mL x 3), twice with 5% NaHSO4 solution (15 mL x 2), once with 5% Na2CO3 solution (15 mL), and once with 10% NaCl solution (15 mL). The obtained organic layer was dried over anhydrous Na2SO4. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-MeLeu-D-MeAla-OtBu (3.18 g, 7.56 mmol). 2-MeTHF (30 mL) and HMDS (11.1 mL, 52.9 mmol) were added to the obtained concentrate, followed by dropwise addition of TMSOTf (8.36 mL, 45.4 mmol). The mixture was stirred for 4 hours, and the completion of the reaction was confirmed by HPLC analysis. Cool the flask and add 15 mL of 5% Na₂CO₃ aqueous solution dropwise to the reaction mixture while maintaining the reaction mixture at 30°C or lower. Transfer all contents of the flask to a separating funnel, add 10 mL of 2-MeTHF and 10 mL of 5% Na₂CO₃ aqueous solution, and remove the aqueous layer. Add 20 mL of 2-MeTHF, followed by gradual addition of 3.0 mL of 85% H₃PO₄. Remove the aqueous layer, wash with 15 mL of 10% NaCl aqueous solution, and concentrate the organic layer under reduced pressure. Purify the concentrate by silica gel column chromatography to obtain Cbz-MeLeu-D-MeAla-OH (2.54 g).

[0572] Yield: 91% (after 2 steps)

[0573] Purity: 99.7%

[0574] Measurement method: HPLC method A, retention time: 11.4 min

[0575] Mass spectrometry: m / z 365.20 ([M+H]) + )

[0576] (Synthesis of raw materials 3) Synthesis of H-MeGly(cPent)-MeAsp(OtBu)-NMe2

[0577] [Formula 30]

[0578]

[0579] The title compound was synthesized by desalting its hydrochloride salt using the method described in International Publication No. WO 2023 / 127869.

[0580] (Synthesis of raw materials 4) Synthesis of Cbz-MeAla-MeLeu-OH

[0581] [Equation 31]

[0582]

[0583] Cbz-MeLeu-OH (2.00 g, 7.20 mmol), cyclohexane (16 mL), and DCM (6 mL) were added to a flask equipped with a stirrer. 2,2,2-Trichloroiminoacetic acid tert-butyl ester (2.6 mL, 14.53 mmol) was added to the flask. While cooling the flask in an ice bath, boron trifluoride-ethyl ether complex (90 μL, 0.72 mmol) was added dropwise, and the mixture was continuously stirred at room temperature for 1 hour. The completion of the reaction was confirmed by HPLC analysis. The reaction mixture was filtered, and the filtered solid was washed with cyclohexane. The filtrates and wash solutions were combined and washed five times with 10% citric acid aqueous solution (16 mL × 5). The resulting organic layer was washed twice with 5% Na₂CO₃ aqueous solution (16 mL × 2). The obtained organic layer was concentrated under reduced pressure to obtain Cbz-MeLeu-OtBu (2.38 g, 7.10 mmol). Cbz-MeLeu-OtBu (2.38 g, 7.10 mmol), 2-MeTHF (24 mL), and 5% Pd / C (1.51 g, 0.36 mmol on a Pd metal substrate) were added sequentially to a flask equipped with a stirrer. Nitrogen and hydrogen purgings were performed in the flask, and the reaction mixture was stirred for 1 hour under a hydrogen atmosphere (1 atm). The reaction mixture was filtered, and the Pd / C was washed with 2-MeTHF. The filtrate and washings were combined and concentrated under reduced pressure to obtain H-MeLeu-OtBu (1.39 g, 6.90 mmol). H-MeLeu-OtBu (1.39 g, 6.90 mmol), MeCN (14.0 mL), Cbz-MeAla-OH (1.80 g, 7.60 mmol), and NMM (1.5 mL, 13.64 mmol) were added sequentially to a flask equipped with a stirrer. While cooling the flask in an ice bath, COMU (3.55 g, 8.29 mmol) was added to the reaction mixture, and the mixture was stirred continuously at room temperature for 3 hours. The completion of the reaction was confirmed by HPLC analysis, and then 2-MeTHF (42 mL), 5% K₂CO₃ aqueous solution (21 mL), and NMI (0.55 mL, 6.90 mmol) were added sequentially to the reaction mixture, and the mixture was stirred continuously for 1 hour. All contents of the flask were transferred to a separatory funnel, and the aqueous layer was removed.The organic layer was washed once with 5% K₂CO₃ aqueous solution (35 mL × 1), three times with 2.5% ammonia aqueous solution (35 mL × 3), twice with 5% NaHSO₄ aqueous solution (35 mL × 2), once with 5% K₂CO₃ aqueous solution (35 mL × 1), and once with 5% NaCl aqueous solution (35 mL × 1). The obtained organic layer was dried with anhydrous Na₂SO₄. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-MeAla-MeLeu-OtBu (2.70 g, 6.42 mmol). Add Cbz-MeAla-MeLeu-OtBu (2.70 g, 6.42 mmol), 2-MeTHF (27.0 mL), and HMDS (5.8 mL, 27.67 mmol) to a flask equipped with a stirrer, followed by dropwise addition of TMSOTf (3.6 mL, 19.89 mmol). Stir the mixture continuously for 3 hours, then add HMDS (2.9 mL, 13.84 mmol) and TMSOTf (1.8 mL, 9.95 mmol) to the reaction mixture. Stir the mixture continuously for another 1.5 hours, then add HMDS (1.4 mL, 6.68 mmol) and TMSOTf (0.95 mL, 5.25 mmol) to the reaction mixture. After confirming a conversion of 93% by HPLC analysis, cool the flask and add dropwise 32 mL of 5% NaHCO3 aqueous solution while maintaining the reaction mixture at 13°C or lower. Transfer all contents of the flask to a separatory funnel and remove the organic layer. Add 2-MeTHF (65 mL) to the resulting aqueous layer, followed by gradual addition of 85% H3PO4 (4.8 mL). Remove the aqueous layer, wash with 5% NaCl aqueous solution (32 mL), and concentrate the resulting organic layer under reduced pressure. Purify the concentrate by silica gel column chromatography to obtain Cbz-MeAla-MeLeu-OH (1.73 g, 4.74 mmol).

[0584] Purity: 99.3%

[0585] Measurement method: HPLC method A, retention time: 12.6 min

[0586] Mass spectrometry: m / z 365.64 ([M+H]) + )

[0587] (Synthesis of raw materials 5) Synthesis of Cbz-Leu-MePhe-OH

[0588] [Equation 32]

[0589]

[0590] Add Cbz-MePhe-OH (4.98 g, 16.00 mmol), cyclohexane (40 mL), and DCM (15 mL) to a flask equipped with a stirrer. Add tert-butyl 2,2,2-trichloroiminoacetate (5.8 mL, 32.41 mmol) to the flask. While cooling the flask in an ice bath, add boron trifluoride-ethyl ether complex (0.20 mL, 1.59 mmol) dropwise, and then continue stirring at room temperature for 2.5 h. Add tert-butyl 2,2,2-trichloroiminoacetate (1.4 mL, 7.82 mmol) and boron trifluoride-ethyl ether complex (0.20 mL, 1.59 mmol) to the reaction mixture, and stir the mixture continuously for 1 h. Confirm the completion of the reaction by HPLC analysis, filter the reaction mixture, and wash the filtered solids with cyclohexane. Combine the filtrates and wash solutions and wash five times with 10% citric acid aqueous solution (40 mL × 5). The obtained organic layer was washed twice with 5% Na₂CO₃ aqueous solution (40 mL × 2). The obtained organic layer was concentrated under reduced pressure to obtain Cbz-MePhe-OtBu (5.02 g, 13.59 mmol). Cbz-MePhe-OtBu (5.02 g, 13.59 mmol), 2-MeTHF (50 mL), and 5% Pd / C (2.88 g, 0.68 mmol on a Pd metal substrate) were added sequentially to a flask equipped with a stirrer. Nitrogen and hydrogen replacements were performed in the flask, and the reaction mixture was stirred for 1.5 h under a hydrogen atmosphere (1 atm). The reaction mixture was filtered, and Pd / C was washed with 2-MeTHF. The filtrate and washing solution were combined and concentrated under reduced pressure to obtain H-MePhe-OtBu (3.19 g, 13.55 mmol). H-MePhe-OtBu (2.01 g, 8.50 mmol), MeCN (20.0 mL), Cbz-Leu-OH (2.48 g, 9.35 mmol), and NMM (1.9 mL, 17.28 mmol) were added sequentially to a flask equipped with a stirrer. COMU (4.37 g, 10.20 mmol) was added to the reaction mixture while the flask was cooled in an ice bath, and the mixture was stirred continuously at room temperature for 3 hours. The completion of the reaction was confirmed by HPLC analysis, and 2-MeTHF (30.0 mL), 5% K₂CO₃ aqueous solution (20.0 mL), and NMI (0.67 mL, 8.41 mmol) were added sequentially to the reaction mixture, and the mixture was stirred continuously for 45 minutes. All contents of the flask were transferred to a separatory funnel, and the aqueous layer was removed.The organic layer was washed three times with 2.5% ammonia solution (25 mL × 3), twice with 5% NaHSO4 solution (25 mL × 2), and once with 5% Na2CO3 solution (25 mL × 1). The obtained organic layer was dried with anhydrous Na2SO4. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-Leu-MePhe-OtBu (4.13 g, 8.56 mmol). Cbz-Leu-MePhe-OtBu (4.13 g, 8.56 mmol), 2-MeTHF (41.0 mL), and HMDS (13.0 mL, 62.02 mmol) were added to a flask equipped with a stirrer, followed by dropwise addition of TMSOTf (9.5 mL, 52.49 mmol). Stirring was continued for 2 hours, and the conversion was then confirmed to be 94% by HPLC analysis. Cool the flask and add 40 mL of 5% NaHCO3 aqueous solution dropwise while maintaining the reaction mixture at 23°C or lower. Transfer all contents of the flask to a separatory funnel and remove the organic layer. Add 50 mL of 2-MeTHF to the resulting aqueous layer and gradually add 4.5 mL of 85% H3PO4. Remove the aqueous layer, wash with 30 mL of 5% NaCl aqueous solution, and concentrate the resulting organic layer under reduced pressure. Purify the concentrate by silica gel column chromatography to obtain Cbz-Leu-MePhe-OH (2.49 g, 5.84 mmol).

[0591] Purity: 98.7%

[0592] Measurement method: HPLC method A, retention time: 12.7 min

[0593] Mass spectrometry: m / z 427.71 ([M+H]) + )

[0594] (Synthesis of raw materials 6) Synthesis of Cbz-MeLeu-MeSer(OtBu)-OH

[0595] [Equation 33]

[0596]

[0597] Add Fmoc-MeSer(OtBu)-OH (1.80 g, 4.53 mmol), cyclohexane (14.4 mL), and DCM (5.4 mL) to a flask equipped with a stirrer. Add tert-butyl 2,2,2-trichloroiminoacetate (1.6 mL, 8.94 mmol) to the flask. While cooling the flask in an ice bath, add boron trifluoride-ethyl ether complex (57 μ mL, 0.454 mmol) dropwise, and then continue stirring at room temperature for 3 hours. Confirm the completion of the reaction by HPLC analysis. Filter the reaction mixture and wash the filtered solid with cyclohexane. Combine the filtrates and wash solutions and wash five times with 10% citric acid aqueous solution (15 mL × 5). Wash the resulting organic layer twice with 5% Na₂CO₃ aqueous solution (15 mL × 2). Dry the obtained organic layer with anhydrous Na₂SO₄. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Fmoc-MeSer(OtBu)-OtBu (2.05 g, 4.52 mmol). Fmoc-MeSer(OtBu)-OtBu (2.05 g, 4.52 mmol) and MeCN (16 mL) were added to a flask equipped with a stirrer. DBU (0.68 mL, 4.55 mmol) was added to the flask, and the mixture was stirred for 30 min. The completion of the reaction was confirmed by HPLC analysis, and TEA (2.5 mL, 17.94 mmol) and water (0.81 mL, 44.95 mmol) were added to the reaction mixture. Sodium bisulfite (1.19 g, 11.44 mmol) was added while the flask was cooled in an ice bath, and the mixture was stirred at room temperature for 1 h. MTBE (50 mL) and 10% ammonia solution (25 mL) were added to the reaction mixture, and all contents of the flask were transferred to a separatory funnel. The aqueous layer was removed, and the resulting organic layer was washed three times with 10% ammonia solution (25 mL × 3) and once with 5% NaCl solution (25 mL × 1). The obtained organic layer was concentrated under reduced pressure to obtain H-MeSer(OtBu)-OtBu. 2-MeTHF (12.0 mL), Cbz-MeLeu-OH (1.39 g, 4.97 mmol), and NMM (1.5 mL, 13.64 mmol) were added to the flask. COMU (2.52 g, 5.88 mmol) was added to the reaction mixture while the flask was cooled in an ice bath, and the mixture was stirred continuously at room temperature for 2 hours.The completion of the reaction was confirmed by HPLC analysis. 2-MeTHF (30 mL), 5% K₂CO₃ aqueous solution (15 mL), and NMI (0.36 mL, 4.52 mmol) were added sequentially to the reaction mixture, and the mixture was stirred continuously for 30 minutes. All contents of the flask were transferred to a separatory funnel, and the aqueous layer was removed. The organic layer was washed once with 5% K₂CO₃ aqueous solution (25 mL × 1), three times with 2.5% ammonia aqueous solution (25 mL × 3), twice with 5% NaHSO₄ aqueous solution (25 mL × 2), once with 5% K₂CO₃ aqueous solution (25 mL × 1), and once with 5% NaCl aqueous solution (25 mL × 1). The obtained organic layer was dried over anhydrous Na₂SO₄. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-MeLeu-MeSer(OtBu)-OtBu (1.98 g, 4.02 mmol). Cbz-MeLeu-MeSer(OtBu)-OtBu (1.98 g, 4.02 mmol), 2-MeTHF (20 mL), and HMDS (6.0 mL, 28.63 mmol) were added to a flask equipped with a stirrer, followed by dropwise addition of TMSOTf (4.4 mL, 24.31 mmol). Stirring was continued for 2.5 hours, and the completion of the reaction was confirmed by HPLC analysis. The flask was cooled, and 5% NaHCO3 aqueous solution (20 mL) was added dropwise while maintaining the reaction mixture at 24°C or lower. All contents of the flask were transferred to a separatory funnel and the organic layer was removed. 2-MeTHF (30 mL) was added to the resulting aqueous layer, followed by gradual addition of 85% H3PO4 (2.25 mL). The aqueous layer was removed, and the resulting organic layer was washed with 5% NaCl aqueous solution (20 mL) and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography to obtain Cbz-MeLeu-MeSer(OtBu)-OH (0.69 g, 1.59 mmol).

[0598] Purity: 99.7%

[0599] Measurement method: HPLC method A, retention time: 14.0 min

[0600] Mass spectrometry: m / z 437.74 ([M+H]) + )

[0601] (Synthesis of raw materials 7) Synthesis of Cbz-Aze-EtPhe(4-Me)-OH

[0602] [Equation 34]

[0603]

[0604] Add Fmoc-EtPhe(4-Me)-OH (5.02 g, 11.60 mmol), cyclohexane (40 mL), and DCM (15 mL) to a flask equipped with a stirrer. Add tert-butyl 2,2,2-trichloroiminoacetate (4.2 mL, 23.47 mmol) to the flask. While cooling the flask in an ice bath, add the boron trifluoride-ethyl ether complex (0.15 mL, 1.19 mmol) dropwise, and then continuously stir the mixture at room temperature for 1 hour. Confirm the completion of the reaction by HPLC analysis. Filter the reaction mixture and wash the filtered solid with cyclohexane. Combine the filtrates and wash solutions and wash five times with 10% citric acid aqueous solution (40 mL × 5). Wash the resulting organic layer twice with 5% Na₂CO₃ aqueous solution (40 mL × 2). Dry the obtained organic layer with anhydrous Na₂SO₄. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Fmoc-EtPhe(4-Me)-OtBu (6.13 g, 12.60 mmol). Fmoc-EtPhe(4-Me)-OtBu (5.65 g, 11.60 mmol) and MeCN (45 mL) were added to a flask equipped with a stirrer. DBU (1.80 mL, 12.04 mmol) was added to the flask, and the mixture was stirred for 30 min. The completion of the reaction was confirmed by HPLC analysis, and TEA (6.5 mL, 46.64 mmol) and water (2.1 mL, 116.54 mmol) were added to the reaction mixture. Sodium bisulfite (3.03 g, 29.12 mmol) was added while the flask was cooled in an ice bath, and the mixture was stirred at room temperature for 1 h. Add MTBE (140 mL) and 10% ammonia solution (85 mL) to the reaction mixture, and transfer all contents of the flask to a separatory funnel. Remove the aqueous layer, and wash the resulting organic layer three times with 10% ammonia solution (85 mL × 3) and once with 5% NaCl solution (85 mL × 1). Concentrate the obtained organic layer under reduced pressure to obtain H-EtPhe(4-Me)-OtBu (3.06 g, 11.60 mmol). Add H-EtPhe(4-Me)-OtBu (3.06 g, 11.60 mmol), 2-MeTHF (28 mL), Cbz-Aze-OH (3.28 g, 13.90 mmol), and DIPEA (16.0 mL, 91.85 mmol) to a flask equipped with a stirrer.While cooling the flask in an ice bath, add 21.0 mL of T3P solution (50% in 2-MeTHF, 11.1 g, 34.9 mmol) to the reaction mixture and stir continuously at room temperature for 2 hours. Confirm the completion of the reaction by HPLC analysis, and add 28 mL of 5% Na2CO3 aqueous solution to the reaction mixture. Transfer all contents of the flask to a separatory funnel and remove the aqueous layer. Wash the resulting organic layer once with 28 mL × 1 of 4% H2SO4 aqueous solution, once with 28 mL × 1 of 10% KHSO4 aqueous solution, once with 28 mL × 1 of 5% Na2CO3 aqueous solution, and once with 28 mL × 1 of 5% NaCl aqueous solution. Dry the obtained organic layer with anhydrous Na2SO4. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-Aze-EtPhe(4-Me)-OtBu (5.42 g, 11.30 mmol). Cbz-Aze-EtPhe(4-Me)-OtBu (5.42 g, 11.30 mmol), 2-MeTHF (54 mL), and HMDS (9.5 mL, 45.32 mmol) were added to a flask equipped with a stirrer, followed by dropwise addition of TMSOTf (6.5 mL, 35.91 mmol). Stirring was continued for 4 hours, and the completion of the reaction was confirmed by HPLC analysis. The flask was cooled, and 5% NaHCO3 aqueous solution (65 mL) was added dropwise while maintaining the reaction mixture at 24°C or lower. All contents of the flask were transferred to a separatory funnel, and the organic layer was removed. 2-MeTHF (108 mL) was added to the resulting aqueous layer, followed by gradual addition of 85% H3PO4 (8.2 mL). The aqueous layer was removed, and the resulting organic layer was washed with 5% NaCl aqueous solution (65 mL) and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography to obtain Cbz-Aze-EtPhe(4-Me)-OH (1.67 g, 3.93 mmol).

[0605] Purity: 99.0%

[0606] Measurement method: HPLC method A, retention time: 11.9 min

[0607] Mass spectrometry: m / z 425.72 ([M+H]) + )

[0608] (Synthesis of raw materials 8) Synthesis of Fmoc-MeAlGly-MeAlGly-OH

[0609] [Formula 35]

[0610]

[0611] Add Fmoc-MeAlGly-OH (1.50 g, 4.27 mmol), cyclohexane (12 mL), and DCM (4.5 mL) to a flask equipped with a stirrer. Add tert-butyl 2,2,2-trichloroiminoacetate (1.5 mL, 8.38 mmol) to the flask. While cooling the flask in an ice bath, add boron trifluoride-ethyl ether complex (54 μL, 0.43 mmol) dropwise, and then continuously stir the mixture at room temperature for 1.5 h. Confirm the completion of the reaction by HPLC analysis. Filter the reaction mixture and wash the filtered solid with cyclohexane. Combine the filtrates and wash solutions and wash five times with 10% citric acid aqueous solution (12 mL × 5). Wash the resulting organic layer twice with 5% Na₂CO₃ aqueous solution (12 mL × 2). Dry the obtained organic layer with anhydrous Na₂SO₄. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Fmoc-MeAlGly-OtBu (1.89 g, 4.64 mmol). Fmoc-MeAlGly-OtBu (1.74 g, 4.27 mmol) and MeCN (14 mL) were added to a flask equipped with a stirrer. DBU (0.64 mL, 4.28 mmol) was added to the flask, and the mixture was stirred for 30 min. The completion of the reaction was confirmed by HPLC analysis, and TEA (2.4 mL, 17.22 mmol) and water (0.77 mL, 42.73 mmol) were added to the reaction mixture. Sodium bisulfite (1.11 g, 10.67 mmol) was added while the flask was cooled in an ice bath, and the mixture was stirred at room temperature for 30 min. MTBE (44 mL) and 10% ammonia solution (24 mL) were added to the reaction mixture, and all contents of the flask were transferred to a separatory funnel. The aqueous layer was removed, and the resulting organic layer was washed three times with 10% ammonia solution (24 mL × 3) and once with 5% NaCl solution (24 mL × 1). The obtained organic layer was concentrated under reduced pressure to obtain H-MeAlGly-OtBu (0.74 g). MeCN (10.0 mL), Fmoc-MeAlGly-OH (1.65 g, 4.70 mmol), and NMM (1.4 mL, 12.73 mmol) were added sequentially to the flask. COMU (2.20 g, 5.14 mmol) was added to the reaction mixture while the flask was cooled in an ice bath, and the mixture was stirred continuously at room temperature for 2 hours. COMU (0.19 g, 0.44 mmol) was added to the reaction mixture, and the mixture was stirred continuously at room temperature for 30 minutes.Add COMU (0.36 g, 0.84 mmol) to the reaction mixture and stir continuously at room temperature for another 30 minutes. Confirm the completion of the reaction by HPLC analysis, and then add 2-MeTHF (24 mL), 5% K₂CO₃ aqueous solution (12 mL), and NMI (0.34 mL, 4.27 mmol) sequentially to the reaction mixture, stirring continuously for 30 minutes. Transfer all contents of the flask to a separatory funnel and remove the aqueous layer. Wash the organic layer four times with 5% K₂CO₃ aqueous solution (20 mL × 4), twice with 5% NaHSO₄ aqueous solution (20 mL × 2), once with 5% K₂CO₃ aqueous solution (20 mL × 1), and once with 5% NaCl aqueous solution (20 mL × 1). Dry the obtained organic layer with anhydrous Na₂SO₄, filter off the desiccant, and then concentrate the filtrate under reduced pressure. The concentrate obtained by silica gel column chromatography was purified to obtain Fmoc-MeAlGly-MeAlGly-OtBu (2.08 g, 4.01 mmol). Fmoc-MeAlGly-MeAlGly-OtBu (2.08 g, 4.01 mmol), 2-MeTHF (20 mL), and HMDS (3.4 mL, 16.22 mmol) were added to a flask equipped with a stirrer, followed by dropwise addition of TMSOTf (2.2 mL, 12.16 mmol). The mixture was continuously stirred for 2 hours, and then HMDS (1.3 mL, 6.20 mmol) and TMSOTf (1.2 mL, 6.63 mmol) were added to the reaction mixture. 2-MeTHF (20 mL) was added to the reaction mixture to dissolve the precipitate. The mixture was stirred continuously for another hour, and then HMDS (2.1 mL, 10.02 mmol) and TMSOTf (1.9 mL, 10.50 mmol) were added to the reaction mixture. Stirring was continued for another hour, and the completion of the reaction was confirmed by HPLC analysis. The flask was cooled, and then 5% NaHCO3 aqueous solution (20 mL) was added dropwise while maintaining the reaction mixture at 13°C or lower. All contents of the flask were transferred to a separatory funnel and the organic layer was removed. 2-MeTHF (30 mL) was added to the resulting aqueous layer, followed by gradual addition of 85% H3PO4 (3.6 mL). The aqueous layer was removed, and the mixture was washed with 5% NaCl aqueous solution (20 mL) and the resulting organic layer was concentrated under reduced pressure.The concentrate obtained by purification by silica gel column chromatography was used to obtain Fmoc-MeAlGly-MeAlGly-OH (1.41 g, 3.05 mmol).

[0612] Purity: 98.1%

[0613] Measurement method: HPLC method A, retention time: 14.6 min

[0614] Mass spectrometry: m / z 463.79 ([M+H]) + )

[0615] (Synthesis of raw materials 9) Synthesis of Cbz-MeLeu-MeIle-OH

[0616] [Formula 36]

[0617]

[0618] Add Cbz-MeIle-OH (4.50 g, 16.00 mmol), cyclohexane (36 mL), and DCM (14 mL) to a flask equipped with a stirrer. Add tert-butyl 2,2,2-trichloroiminoacetate (5.8 mL, 32.41 mmol) to the flask. While cooling the flask in an ice bath, add boron trifluoride-ethyl ether complex (0.20 mL, 1.59 mmol) dropwise, and then continuously stir the mixture at room temperature for 2 hours. Confirm the completion of the reaction by HPLC analysis, filter the reaction mixture, and wash the filtered solid with cyclohexane. Combine and wash the filtrate and wash solution five times with 10% citric acid aqueous solution (36 mL × 5). Wash the resulting organic layer twice with 5% Na2CO3 aqueous solution (36 mL × 2). Concentrate the obtained organic layer under reduced pressure to obtain Cbz-MeIle-OtBu (5.11 g, 15.20 mmol). Cbz-MeLeu-OtBu (5.11 g, 15.20 mmol), 2-MeTHF (51 mL), and 5% Pd / C (3.24 g, 0.76 mmol on a Pd metal substrate) were added sequentially to a flask equipped with a stirrer. Nitrogen and hydrogen purgings were performed in the flask, and the reaction mixture was stirred for 2 hours under a hydrogen atmosphere (1 atm). The reaction mixture was filtered, and the Pd / C was washed with 2-MeTHF. The filtrate and washings were combined and concentrated under reduced pressure to obtain H-MeLeu-OtBu (2.73 g, 13.57 mmol). H-MeLeu-OtBu (2.73 g, 13.57 mmol), MeCN (27.0 mL), Cbz-MeLeu-OH (4.17 g, 14.90 mmol), and NMM (4.5 mL, 40.93 mmol) were added sequentially to a flask equipped with a stirrer. While cooling the flask in an ice bath, COMU (7.55 g, 17.63 mmol) was added to the reaction mixture, and the mixture was stirred continuously at room temperature for 4 hours. COMU (0.58 g, 1.35 mmol) was then added, and the mixture was stirred continuously at room temperature for 30 minutes. The completion of the reaction was confirmed by HPLC analysis, and 2-MeTHF (80 mL), 5% K₂CO₃ aqueous solution (40 mL), and NMI (1.0 mL, 12.55 mmol) were added sequentially to the reaction mixture, and the mixture was stirred continuously for 30 minutes. All contents of the flask were transferred to a separatory funnel, and the aqueous layer was removed.The organic layer was washed once with 5% K₂CO₃ aqueous solution (40 mL × 1), three times with 2.5% ammonia aqueous solution (70 mL × 3), twice with 5% NaHSO₄ aqueous solution (70 mL × 2), once with 5% K₂CO₃ aqueous solution (70 mL × 1), and once with 5% NaCl aqueous solution (70 mL × 1). The obtained organic layer was dried with anhydrous Na₂SO₄. The desiccant was filtered off, and the filtrate was then concentrated under reduced pressure to obtain Cbz-MeLeu-MeIle-OtBu (5.99 g, 12.95 mmol). Add Cbz-MeLeu-MeIle-OtBu (5.99 g, 12.95 mmol), 2-MeTHF (60.0 mL), and HMDS (19.0 mL, 90.64 mmol) to a flask equipped with a stirrer, followed by dropwise addition of TMSOTf (14.0 mL, 77.35 mmol). Stir the mixture continuously for 6 hours, then add HMDS (8.0 mL, 38.17 mmol) and TMSOTf (4.8 mL, 26.52 mmol) to the reaction mixture. Continue stirring for 30 minutes, and then confirm a conversion of 94% by HPLC analysis. Cool the flask and add dropwise 5% NaHCO3 aqueous solution (60 mL) while maintaining the reaction mixture at 24°C or lower. Transfer all contents of the flask to a separatory funnel and remove the organic layer. 2-MeTHF (90 mL) was added to the resulting aqueous layer, followed by gradual addition of 85% H3PO4 (8.5 mL). The aqueous layer was removed, and the resulting organic layer was washed with 5% NaCl aqueous solution (60 mL) and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography to obtain Cbz-MeLeu-MeIle-OH (3.09 g, 7.59 mmol).

[0619] Purity: 97.7%

[0620] Measurement method: HPLC method A, retention time: 13.8 min

[0621] Mass spectrometry: m / z 407.70 ([M+H]) + )

[0622] Synthesis of H-MeGly(nPr)-Ile-Pro-OtBu (Raw Material Synthesis 10)

[0623] [Formula 37]

[0624]

[0625] Step 10-1

[0626] Compound 10-1: (2S)-1-[(2S,3S)-2-(benzyloxycarbonylamino)-3-methyl-pentanoyl]pyrrolidine- Synthesis of tert-butyl 2-carboxylate

[0627] [Formula 38]

[0628]

[0629] In a reactor undergoing nitrogen replacement, tert-butyl (2S)-pyrrolidine-2-carboxylate (18.8 g), (2S,3S)-2-(benzyloxycarbonylamino)-3-methylvaleric acid (20.0 g), and DMF (140 mL) were added at room temperature, and the mixture was stirred. After confirming complete dissolution, the mixture was cooled to 0°C, and DIPEA (52.7 mL) was added. A solution of 50 wt.% propylphosphonic anhydride in ethyl acetate (58.3 mL) was added to the mixture at 0°C over 20 minutes, and the mixture was stirred at 0°C for 1.5 hours. Water (100 mL) and ethyl acetate (200 mL) were added to the mixture in this order. Aqueous layer 1 and organic layer 1 were separated by liquid-liquid separation, and aqueous layer 1 was separated. Organic layer 1 was washed with 5% potassium bisulfate aqueous solution (100 mL), 5% sodium carbonate aqueous solution (100 mL), and 10% brine (100 mL). Water (100 mL) and ethyl acetate (200 mL) were added to the separated aqueous layer 1 and the mixture was stirred. The mixture was then separated by liquid-liquid separation to obtain organic layer 2. Organic layers 1 and 2 were combined and concentrated under reduced pressure to obtain compound 10-1 (33.8 g).

[0630] LCMS (ESI) of compound 21-1: Retention time: 2.75 min, m / z = 419 [M+H] +

[0631] Step 10-2

[0632] Compound 10-2: (2S)-1-[(2S,3S)-2-amino-3-methyl-pentanoyl]pyrrolidine-2-carboxylic acid tert-butyl ester Synthesis

[0633] [Formula 39]

[0634]

[0635] Compound 10-1 (31.6 g) and 2-MeTHF (221 mL) obtained in step 10-1 were added to the reactor in which nitrogen replacement was performed, and the mixture was cooled to 10°C. 5% Pd / C (6.32 g, 50% wetted with water) was added to the mixture, followed by the addition of triethylsilane (60.3 mL) over 20 minutes. The mixture was stirred at an internal temperature of 15°C for 6 hours, and then stirred at room temperature for an additional 17 hours. The mixture was filtered, and the filtrate was concentrated under reduced pressure to obtain compound 10-2. Compound 10-2 was used in step 10-3 without further purification.

[0636] LCMS (ESI) of compound 21-2: Retention time: 1.14 min, m / z = 285 [M+H] +

[0637] Step 10-3

[0638] Compound 10-3: (2S)-1-[(2S,3S)-2-[[(2S)-2-[9H-fluorene-9-ylmethoxycarbonyl(methyl)amino] Synthesis of tert-butyl pyrrolidine-2-carboxylate [amino]-3-methyl-pentanoyl]pyrrolidine-2-carboxylate

[0639] [Formula 40]

[0640]

[0641] Acetonitrile (221 mL) was added to compound 10-2 obtained in step 10-2 at 5 °C, followed by (2S)-2-[9H-fluorene-9-ylmethoxycarbonyl(methyl)amino]valeric acid (28.0 g) and DIPEA (39.6 mL). HATU (34.5 g) was slowly added to the mixture at 2.5 °C. The mixture was stirred at 2.5 °C for 1 hour, and then at room temperature for 2.5 hours. 5% sodium carbonate aqueous solution (189 mL) and water (150 mL) were added to the mixture in this order. Toluene (80 mL) and 2-MeTHF (140 mL) were added, and the mixture was stirred and then subjected to liquid-liquid separation. The organic layer was washed twice with 5% potassium bisulfate aqueous solution (190 mL) and twice with 10% brine (190 mL). The obtained organic layer was concentrated under reduced pressure to obtain compound 10-3. In step 10-4, compound 10-3 is used without further purification.

[0642] LCMS (ESI) of compound 10⁻³: Retention time: 3.43 min, m / z = 620 [M+H] +

[0643] Step 10-4

[0644] Compound 10-4: (2S)-1-[(2S,3S)-3-methyl-2-[[(2S)-2-(methylamino)pentanoyl]amino] Synthesis of tert-butyl 2-acetate [pentanoyl]pyrrolidine (Synthesis of H-MeGly(nPr)-Ile-Pro-OtBu)

[0645] [Formula 41]

[0646]

[0647] Compound 10-3 (296 mg), synthesized by the same method as in step 10-3, and toluene (2.07 mL) were added to the reactor in which nitrogen replacement was performed, and the mixture was stirred. DBU (0.072 mL) was added to the mixture, and the mixture was stirred for 30 minutes. Acetonitrile (1.00 mL) was added to the mixture, and the mixture was stirred for 30 minutes, and DBU (0.072 mL) was added, and the mixture was stirred for another 30 minutes. 1 M hydrochloric acid (2.00 mL) and n-heptane (1.00 mL) were added, and the mixture was stirred, and then aqueous layer 1 and organic layer 1 were separated. Organic layer 1 was extracted with 1 M hydrochloric acid (1.00 mL) to provide aqueous layer 2 containing compound 10-4. Aqueous layer 1 and aqueous layer 2 were combined and extracted with 5% potassium carbonate aqueous solution (2.00 mL) and toluene (4.00 mL) to separate the organic layer containing compound 10-4. The organic layer was washed with 10% saline (2.00 mL) and then concentrated under reduced pressure to obtain compound 10⁻⁴ (166 mg).

[0648] LCMS (ESI) of compound 10⁻⁴: Retention time: 1.36 min, m / z = 398 [M+H] +

[0649] The following shows the analytical conditions for LCMS of compounds 10⁻¹ to 10⁻⁴.

[0650] Equipment: Waters UPLC / SQD

[0651] Column: Ascentis Express RP 90A amide, 2.1 mm ID × 50 mm, 2.7 μm

[0652] Mobile phase: 0.1% FA / water (A), 0.1% FA / MeCN (B)

[0653] Elution method: B) 5% (0 min) → 100% (4.5 min) → 100% (5.0 min) → 5% (5.01 min) → 5% (7 min)

[0654] Flow rate: 0.5 mL / min

[0655] Column temperature: 40℃

[0656] Detection wavelength: 210-400 nm (PDA)

[0657] Industrial applicability

[0658] According to the present invention, a method for synthesizing peptide compounds with high diastereoselectivity and high yield even by fragment coupling can be provided.

Claims

1. A method for producing a peptide compound or a salt thereof, the method comprising the step of linking an amino group of a first amino acid or peptide to a carboxyl group of a second amino acid or peptide via an amide bond (the linking step), wherein a separate condensing agent and one or more additives are used in the linking step, and said one or more additives are selected from 2-hydroxypyridine-N-oxide (HOPO), 1-hydroxy-7-azabenzotriazole (HOAt), 3,4-dihydro-3-hydroxy-4-oxo-benzotriazine (HOOBt), ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt), 2,2,3,3,3-pentafluoro-1-propanol (PfpOH), ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma), 5-(hydroxyimino)-1,3-dimethylpyrimidin-2,4,6-(1H,3H,5H)-trione (Oxyma-B), and N-hydroxysuccinimide (HOSu). One or more of the group consisting of potassium salt of (hydroxyimino)cyanoethyl acetate (K-Oxyma).

2. The method according to claim 1, wherein the one or more additives are selected from the group consisting of HOPO, HOAt, HOOBt, HOCt, Oxyma, Oxyma-B and HOSu.

3. The method according to claim 1, wherein the independent condensing agent has a structure in the molecule represented by any one of the following formulas (1) to (4): [Formula 1] [Equation 2] [Formula 3] wherein R 4 is CH or N, [Formula 4] 。 4. The method according to claim 1, wherein the independent condensing agent has a structure in the molecule represented by any one of the following formulas (5) to (7): [Formula 5] [Formula 6] [Formula 7] 。 5. The method according to claim 1, wherein the independent condensing agent is selected from 2-cyano-2-((dimethylimino)(morpholinyl)methyloxime)ethyl acetate hexafluorophosphate (COMU), 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), O-[(ethoxycarbonyl)cyanomethyleneamino]-N,N,N',N'-tetramethylureonium hexafluorophosphate (HOTU), O At least one of the following groups: -(3,4-dihydro-4-oxo-1,2,3-benzotriazine-3-yl)-N,N,N',N'-tetramethylureon tetrafluoroborate (TDBTU), 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazine-4(3H)-one (DEPBT), O-[2-oxo-1(2H)-pyridyl]-N,N,N',N'-tetramethylureon tetrafluoroborate (TPTU), 2-bromo-1-ethylpyridinium tetrafluoroborate (BEP), and salicylamino-2-benzylthiophenol (Ph2CP).

6. The method according to any one of claims 1 to 5, wherein one or more additives are used in a molar equivalent of 0.1 to 5.0 relative to the first amino acid or peptide.

7. The method of any one of claims 1 to 6, wherein the amino group containing a nitrogen atom located beta to the carboxyl of the second amino acid or peptide is represented by the formula: -NR 5 wherein R 5 is a hydrogen atom, a linear C1-C6 alkyl group, a branched C3-C6 alkyl group, or a C3-C8 cycloalkyl group.

8. The method of any one of claims 1 to 7, wherein the amino group of the first amino acid or peptide is an amino group represented by the formula: -NR 6 R 7 wherein R 6 is a hydrogen atom, and R 7 is a hydrogen atom, a linear C1-C6 alkyl group, a branched C3-C6 alkyl group, or a C3-C8 cycloalkyl group.

9. The method of any one of claims 1 to 8, wherein the a-carbon of the carboxyl of the second amino acid or peptide is represented by the formula: -CR 8 R 9 wherein R 8 and R 9 are the same or different and each is a hydrogen atom, a straight chain C1-C4 alkyl group, an optionally substituted branched C3-C6 alkyl group, an optionally substituted phenyl C1-C2 alkyl group, or an optionally substituted 5- to 6-membered heteroaryl C1-C2 alkyl group.

10. The method according to any one of claims 1 to 9, wherein the base used in the connecting step is at least one selected from the group consisting of dicyclohexylmethylamine, diisopropylethylamine, triethylamine, 2,6-dimethylpyridine, N-methylmorpholine, 4-N,N-dimethylaminopyridine and 2,4,6-trimethylpyridine.

11. The method according to any one of claims 1 to 10, wherein the joining step is performed by liquid-phase synthesis.

12. The method according to any one of claims 1 to 11, wherein the peptide compound or its salt produced contains 8 to 20 amino acid residues.

13. The method according to any one of claims 1 to 12, wherein the peptide compound produced contains at least one non-natural amino acid residue.

14. A peptide compound or a salt thereof, produced by the method according to any one of claims 1 to 13.

15. A pharmaceutical composition comprising a peptide compound or a salt thereof produced by the method according to any one of claims 1 to 13.

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