WO2023033016A1 - Arginine derivative - Google Patents

Abstract

Provided are: a guanidyl-protected arginine compound which, when used in a liquid-phase peptide synthesis reaction, renders satisfactory liquid-liquid separation possible; and a peptide synthesis method in which the guanidyl-protected arginine compound is used.　The present invention relates to an arginine derivative represented by formula (1), (2), or (3) or a salt thereof. (In the formulae, R1 and R2 are the same or different and each represent a hydrogen atom or a C1-C4 alkyl group, A represents a hydrogen atom or an amino-protecting group, R3 and R4 each represent a hydrogen atom or a Boc group, with the proviso that at least one of them is a Boc group, R5 and R6 each represent a hydrogen atom or a Boc group, with the proviso that at least one of theme is a Boc group, R7 and R8 each represent a hydrogen atom or a Boc group, with the proviso that at least one of them is a Boc group, and n represents an integer of 1-6 (with the proviso that the case where n is 3, R1 and R2 are each a hydrogen atom or a methyl group, and R3 to R8 are Boc groups is excluded).)

Description

Arginine derivative

The present invention relates to arginine derivatives or salts thereof.

When synthesizing peptides, it is necessary to protect functional groups that are not elongation points of raw material amino acids in advance to prevent side reactions, decomposition, etc. caused by those parts. Even when arginines are used as raw materials, the guanidyl group is protected in advance, and after the condensation reaction between the α-amino group and the carboxyl group of another amino acid, the protective group is removed as necessary. .

Methods for protecting the guanidyl group of arginines in liquid-phase peptide synthesis have traditionally been (1) protection with a nitro group, (2) protection with a 2,4,6-trimethylphenylsulfonyl (TMS) group, and (3) strong acid. Protection by protonation with the action of (for example, hydrochloric acid) has been known (Patent Document 1). Furthermore, various protective groups have been developed for arginines, and currently the most commonly used protective groups are p-toluenesulfonyl (Tos), 2,2,5,7,8-pentamethylchroman-6-sulfonyl ( Pmc), 2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl (Pbf), and the like. However, protection methods other than proton protection require severe conditions during deprotection, which affects other parts of the structure. It has been used in peptide synthesis reactions without using specific protecting groups (Patent Documents 2 to 5).
In recent years, indole sulfonyl has been developed as a new protective means for guanidyl groups (Patent Document 6). However, this compound is difficult to obtain and is not widely available for general use.

In recent years, liquid-phase peptide synthesis carriers (tags) have been reported (Patent Documents 7 to 22). Since this carrier is a highly hydrophobic compound, by binding highly hydrophilic amino acids, peptides, amino acid amides or peptide amides (hereinafter sometimes referred to as amino acids, etc.) to this carrier, solubility in organic solvents can be improved. can be greatly improved. Therefore, when a peptide elongation reaction is carried out with an amino acid or the like bound to the present carrier, the amino acid or the like bound to the carrier is dissolved in the organic layer, and unnecessary components such as surplus raw material amino acids used in the peptide elongation reaction and its By dissolving in the aqueous layer the decomposition products and compounds produced as by-products when the protective groups of the starting amino acids are deprotected, there is an advantage that the amino acids bound to the carrier can be simply purified by liquid-liquid separation.
As used herein, the term "amino acid amide" means a structure in which the C-terminal carboxy group (--COOH) of an amino acid is replaced by an amide group (--CONH ₂ ). In addition, "peptide amide" means a structure in which the C-terminal carboxyl group of a peptide is an amide group.
Furthermore, when described as "liquid-liquid separation" in this specification, the above-mentioned step, that is, dissolving the amino acid etc. bound to the carrier in the organic layer, unnecessary components such as surplus raw material amino acids used in the peptide elongation reaction, It is a step of dissolving in the water layer the decomposition product, the compound by-produced when the protecting group of the starting amino acid is deprotected, and the like.

JP-A-61-36299 Japanese Patent Publication No. 2003-500416 Japanese translation of PCT publication No. 2004-516330 JP-A-4-211096 JP-A-5-170795 JP 2014-193872 A Japanese Patent No. 5113118 Patent No. 4500854 Japanese Patent No. 5929756 Japanese Patent No. 6092513 Japanese Patent No. 5768712 Japanese Patent No. 5803674 Japanese Patent No. 6116782 Japanese Patent No. 6201076 Japanese Patent No. 6283774 Japanese Patent No. 6283775 Japanese Patent No. 6322350 Japanese Patent No. 6393857 Japanese Patent No. 6531235 WO2019/009317 WO2020/175472 WO2020/175473 Japanese Patent No. 6703668 Japanese Patent No. 6713983 WO2021/132545

Molecules 2021, 26, 3497-3505.

However, in liquid-phase peptide synthesis carried out in an organic solvent using a carrier for liquid-phase peptide synthesis, when a compound obtained by protonating the guanidyl group of an arginine is subjected to a peptide elongation reaction, the organic layer and the aqueous layer are separated by emulsification. In some cases, liquid-liquid separation of arginines bound to the obtained carrier for liquid-phase peptide synthesis could not be performed. It was also found that when liquid-liquid separation is carried out under acidic conditions in order to eliminate emulsification, a problem arises in that protective groups for amino acids and carboxyl groups are removed.
Accordingly, an object of the present invention is to provide guanidyl group-protected arginines that enable good liquid-liquid separation after binding to a carrier for liquid-phase peptide synthesis when a compound having a guanidyl group is used in a liquid-phase peptide synthesis reaction, and to provide a peptide synthesis method using the same.

Accordingly, the present inventors conducted various studies on means for protecting the guanidyl group of arginines used in liquid-phase peptide synthesis. The inventors have found that the liquid-liquid separation after binding with is good and that the Boc protecting group can be removed under mild conditions, and completed the present invention.

That is, the present invention provides the following inventions [1] to [7].
[1] An arginine derivative represented by the following formula (1), (2) or (3) or a salt thereof.

(wherein R ¹ and R ² are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A represents a hydrogen atom or a protective group for an amino group;
R ³ and R ⁴ represent a hydrogen atom or a Boc group, either one or both of which is a Boc group,
R ⁵ and R ⁶ represent a hydrogen atom or a Boc group, one or both of which is a Boc group,
R ⁷ and R ⁸ represent a hydrogen atom or a Boc group, one or both of which is a Boc group,
n is an integer of 1 to 6 (except when n is 3, R ¹ and R ² are hydrogen atoms or methyl groups, and R ³ to R ⁸ are Boc groups);
[2] The arginine derivative or salt thereof according to [1], wherein n in formula (1), (2) or (3) is 4.
[3] The arginine derivative or salt thereof according to [1] or [2], wherein in formula (1), (2) or (3), A is a hydrogen atom, an Fmoc group, or a Cbz group.
[4] The arginine derivative or salt thereof according to any one of [1] to [3], wherein in formula (1), (2) or (3), R ¹ and R ² are ethyl groups.
[5] The arginine derivative or salt thereof according to any one of [1] to [4], wherein in formula (1), (2) or (3), A is an Fmoc group.
[6] The arginine derivative or salt thereof according to any one of [1] to [5], wherein in formula (1), (2) or (3), R ³ to R ⁸ are Boc groups.
[7] A liquid-phase peptide synthesis method using the arginine derivative or its salt according to any one of [1] to [6].

When liquid-phase peptide synthesis is performed using the arginine derivative of the present invention or a salt thereof, liquid-liquid separation between the compound obtained by binding the arginine derivative of the present invention and the carrier for liquid-phase peptide synthesis and other unnecessary components is excellent. and deprotection of the guanidyl group portion of the arginine derivative can be carried out under mild conditions.
Therefore, peptides having arginine residues can be efficiently produced by the liquid phase method.

In the liquid-liquid separation in the step of Example (3-d) *1, this is a photograph of the liquid surface after the separating funnel was shaken and allowed to stand at room temperature for 25 minutes. In the liquid-liquid separation in the step of Comparative Example (1-d) *2, this is a photograph of the liquid surface after the separating funnel was shaken and allowed to stand at room temperature for 25 minutes.

The arginine derivative or salt thereof of the present invention is characterized in that one or both of the amino group and imino group in the guanidino group are protected with a Boc group. Specifically, it is an arginine derivative represented by the following formula (1), (2) or (3) or a salt thereof.

(wherein R ¹ and R ² are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A represents a hydrogen atom or a protective group for an amino group;
R ³ and R ⁴ represent a hydrogen atom or a Boc group, either one or both of which is a Boc group,
R ⁵ and R ⁶ represent a hydrogen atom or a Boc group, one or both of which is a Boc group,
R ⁷ and R ⁸ represent a hydrogen atom or a Boc group, one or both of which is a Boc group,
n is an integer of 1 to 6 (except when n is 3, R ¹ and R ² are hydrogen atoms or methyl groups, and R ³ to R ⁸ are Boc groups);

In the present invention, arginines refer to compounds such as arginine and homoarginine, which have a guanidinoalkylglycine structure and have an alkyl group or protective group on the guanidino group, α-amino group or carboxyl group.
The structures represented by the above formulas (1), (2) and (3) are E/Z isomers or imino/amino isomers, and the arginine derivative of the present invention is a mixture of these isomers. There may be.

R ¹ and R ² are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Here, examples of alkyl groups having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group and tert-butyl group. Among them, a methyl group, an ethyl group, an n-propyl group and an n-butyl group are preferred, a methyl group and an ethyl group are more preferred, and an ethyl group is even more preferred.
Both R ¹ and R ² are more preferably ethyl groups.

A represents a hydrogen atom or a protective group for an amino group. Here, the amino-protecting group includes Boc (tert-butoxycarbonyl) group, Fmoc (9-fluorenylmethyloxycarbonyl) group, Cbz (benzyloxycarbonyl) group, Trt (trityl) group, Mmt (mono methoxytrityl) group, ivDde (4,4-dimethyl-2,6-dioxocyclohex-1-ylidene-3-methylbutyl) group, Ns (2-nitrobenzenesulfonyl) group, DNs (2,4-dinitrobenzenesulfonyl ) group, Nos (4-nitrobenzenesulfonyl) group, Alloc (allyloxycarbonyl) group, Teoc (2-(trimethylsilyl)ethoxycarbonyl) group, Troc (2,2,2-trichloroethoxycarbonyl) group, Phth (phthaloyl) ” group, SES ((2-trimethylsilyl)-ethanesulfonyl) group, and the like. Among these, A is preferably an amino group-protecting group that can be deprotected under conditions different from the Boc group, more preferably a hydrogen atom, an Fmoc group or a Cbz group, and still more preferably an Fmoc group.

R ³ and R ⁴ represent a hydrogen atom or a Boc group, one or both of which are a Boc group, R ⁵ and R ⁶ represent a hydrogen atom or a Boc group, one or both of which are a Boc group. and R ⁷ and R ⁸ represent a hydrogen atom or a Boc group, either one or both of which is a Boc group.
From the viewpoint of protecting the guanidino group and improving liquid-liquid separation in peptide synthesis, all of R ³ to R ⁸ are preferably Boc groups.

　n represents an integer of 1 to 6. Of these, 3 to 6 are preferred, 3 to 5 are more preferred, and 4 is even more preferred.

R ¹ and R ² are preferably a methyl group or an ethyl group, more preferably an ethyl group; A is preferably a hydrogen atom, an Fmoc group or a Cbz group, more preferably an Fmoc group; More preferably, all of ³ to R ⁸ are Boc groups; n is preferably 3 to 6, more preferably 3 to 5, and even more preferably 4.

provided that from the compound represented by formula (1), (2) or (3), n is 3, R ¹ and R ² are hydrogen atoms or methyl groups, and R ³ to R ⁸ are Boc groups; Compounds are excluded.

Salts of arginine derivatives represented by the above formula include acid addition salts such as hydrochloride, sulfate, nitrate, acetate, phosphate, formate, and oxalate; sodium salt, potassium salt, calcium salt; metal salts such as

The arginine derivative represented by the formula (1), (2) or (3) or a salt thereof is, for example, an arginine compound represented by the following formula (4), (5) or (6) or a salt thereof , di-tert-butyl dicarbonate, N-tert-butoxycarbonylimidazole, or other Boc agent.
The amount of the Boc agent to be added may be 1 equivalent or more, more preferably 1 to 15 equivalents, still more preferably 1 to 10 equivalents, relative to the arginine derivative.

(wherein R ¹ and R ² are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A represents a hydrogen atom or a protective group for an amino group;
n represents an integer of 1 to 6 (except when n is 3, R ¹ and R ² are hydrogen atoms or methyl groups, and R ³ to R ⁸ are hydrogen atoms))

This Boc-forming reaction is preferably carried out in a solvent in the presence of a base. The base may be an organic base such as pyridine, triethylamine, DMAP (4-dimethylaminopyridine), N-methylimidazole, or a mixed organic base thereof, and an inorganic base such as sodium carbonate, potassium carbonate, sodium hydrogen carbonate, sodium hydroxide. A base may be used.
The amount of the base to be added may be 0.1 equivalent or more, more preferably 0.1 to 30 equivalents, still more preferably 1 to 20 equivalents, relative to the arginine derivative.
As the reaction solvent, water, THF, 2-MeTHF, 1,4-dioxane, toluene, DMF, acetonitrile, dichloromethane, chloroform, methanol, ethanol, or a mixed solvent thereof is used. The reaction is preferably carried out at 0° C. to 40° C. for 1 to 24 hours.

The arginine derivative of the present invention is useful as a raw material for arginines in solid-phase peptide synthesis or liquid-phase peptide synthesis. Moreover, when used for liquid-phase peptide synthesis, the liquid-liquid separation is excellent, and the elimination reaction of the Boc group is possible under mild conditions. Here, the liquid-phase peptide synthesis reaction is preferably carried out using a recently developed carrier for liquid-phase peptide synthesis.

As such a liquid-phase peptide synthesis method, usual liquid-phase peptide synthesis may be performed except that the arginine derivative of the present invention is used in the arginine condensation step. Manufacturing methods are preferred. The order of step b and step c does not matter, and step b may be followed by step c, that is, the organic solvent layer containing the condensate may be obtained after removing the protective group for the amino group, or step c may be followed by step c. The protective group for the amino group may be removed in the order of step b, that is, after obtaining the organic solvent layer containing the condensate.
a. In a solvent, including an organic solvent,
1. reaction of condensing the arginine derivative of the present invention with a carrier for liquid-phase peptide synthesis;
or 2. a step of condensing the arginine derivative of the present invention with an amino acid, peptide, amino acid amide or peptide amide bound to a carrier for liquid phase peptide synthesis;
b. removing the amino-protecting group (e.g., Fmoc group) of the arginine derivative in the reaction solution;
c. After adding an aqueous solution to the reaction solution, liquid separation is performed,
1. a condensate of the arginine derivative from which the amino-protecting group has been removed and a carrier for liquid-phase peptide synthesis;
or 2. A step of obtaining an organic solvent layer containing either an amino acid, a peptide, an amino acid amide or a peptide amide condensate bound to the arginine derivative from which the amino protecting group has been removed and a carrier for liquid phase peptide synthesis.

Here, a step of adding a quenching agent for the amino acid active ester produced in step a to the reaction solution after the condensation reaction in step a may be included. The amino acid active ester quenching agent is a compound having an amino group in the molecule, and compounds described in Patent Documents 23 to 25, Non-Patent Document 5, etc. can be used.
Such quenching agents include hydroxylamine, amidosulfuric acid, hydroxylamine-O-sulfonic acid, hydroxylamine-O-phosphonic acid, alkylamines having primary or secondary amines, fragrances having primary or secondary amines. Group amines can be used, and tertiary amines can also be used. Furthermore, since excess quenching agent can be removed to the aqueous layer by liquid-liquid separation, it is preferably water-soluble, and amines having hydrophilic substituents such as hydroxyl group, sulfo group, sulfate group and phosphoric acid group are preferred. Further, the number of amino groups in the compound may be one (monovalent), or may be bivalent or more. Specifically, propylamine, methylamine, hexylamine, aniline, toluidine, 2,4,6-trimethylaniline, anisidine, phenetidine, benzylamine, hydroxylamine, 1-methylpiperazine, 4-aminopiperidine, diethylenetriamine, tri Aminoethylamine, 1-ethylpiperazine, N,N-dimethylethylenediamine, ethylenediamine, piperazine, 2-(2-aminoethoxy)ethanol (AEE), taurine, 2-aminoethylsulfate (AEHS) and the like can be mentioned. Also, NMI (N-methylimidazole), DMAP (dimethylaminopyridine), and trimethylamine can be mentioned.

The carrier for liquid-phase peptide synthesis used in step a is a carrier that protects amino acids, peptides, amino acid amides or peptide amides (amino acids, etc.) and solubilizes the protected amino acids, etc. in organic solvents.
Examples of such carriers for liquid-phase peptide synthesis include compounds represented by the following formula (I).

[In the formula,
Ring A represents a C4-20 aromatic ring which may contain heteroatoms and may be polycyclic;
R ¹¹ is a hydrogen atom, or when ring A is a benzene ring and Rb is a group represented by the following formula (b), together with R ¹³ represents a single bond, and ring A and may form a fluorene ring together with ring B, or may form a xanthene ring together with ring A and ring B via an oxygen atom;
p X ¹ are each independently a single bond, -O-, -S-, -C(=O)O-, -C(=O)NH-, -NHC(=O)-, or - NR ¹⁵ — (R ¹⁵ represents a hydrogen atom, an alkyl group or an aralkyl group);
p R ¹² are each independently an aliphatic hydrocarbon group, an aliphatic hydrocarbon group substituted with an aliphatic hydrocarbon group via an oxygen atom, or an organic group represented by formula (a) indicate;

However, R ¹⁶ represents a linear or branched alkylene group having 6 to 16 carbon atoms, and X ³ is an oxygen atom or —C(=O)NR ¹⁷ — (R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). A represents either a silyl group or an alkyl group to which a silyloxy group is attached;
p represents an integer of 1 to 4;
Ring A is, in addition to p X ¹ R ¹² , a halogen atom, a C1-6 alkyl group optionally substituted with a halogen atom, and a C1-6 alkoxy group optionally substituted with a halogen atom It may have a substituent selected from the group consisting of;
Ra represents a hydrogen atom or an aromatic ring optionally substituted with a halogen atom;
Rb represents a hydrogen atom, an aromatic ring optionally substituted with a halogen atom, or a group represented by formula (b);

(Wherein, * indicates the binding position;
q represents an integer from 0 to 4;
q X ² are each independently a single bond, -O-, -S-, -C(=O)O-, -C(=O)NH-, -NHC(=O)-, or - NR ¹⁸ — (R ¹⁸ represents a hydrogen atom, an alkyl group or an aralkyl group);
q R ¹⁴ are each independently an aliphatic hydrocarbon group, an aliphatic hydrocarbon group substituted with an aliphatic hydrocarbon group via an oxygen atom, or an organic group represented by formula (a) indicate;

However, R ¹⁶ represents a linear or branched alkylene group having 6 to 16 carbon atoms, and X ³ is an oxygen atom or —C(=O)NR ¹⁷ — (R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). A represents either a silyl group or an alkyl group to which a silyloxy group is attached;
R ¹³ represents a hydrogen atom, represents a single bond together with R ¹¹ to form a fluorene ring together with ring A and ring B, or forms a xanthene ring together with ring A and ring B through an oxygen atom. may form;
Ring B, in addition to q X ² R ¹⁴ , further comprises a halogen atom, a C1-6 alkyl group optionally substituted with a halogen atom, and a C1-6 alkoxy group optionally substituted with a halogen atom may have a substituent selected from the group consisting of )
Y represents a hydroxy group, a thiol group, NHR ²⁰ (R ²⁰ represents a hydrogen atom, an alkyl group or an aralkyl group) or a halogen atom. ]

Ring A in formula (I) represents a C4-20 aromatic ring which may contain a heteroatom and may be monocyclic or polycyclic. The aromatic ring includes a C6-20 aromatic hydrocarbon ring and a C4-10 aromatic heterocyclic ring.
Specific C6-20 aromatic hydrocarbon rings include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, triphenylene ring, tetracene ring, indane ring, indene ring, fluorene ring, biphenyl ring, 1,1′- A binaphthalene ring and the like can be mentioned. Among these, a benzene ring, a naphthalene ring, a phenanthrene ring, and a fluorene ring are more preferable.
The C4-10 aromatic heterocycle is preferably a 5- to 10-membered aromatic heterocycle containing 1 to 3 heteroatoms selected from nitrogen, oxygen and sulfur atoms, specifically , pyrrole ring, furan ring, thiophene ring, indole ring, benzofuran ring, benzothiophene ring, carbazole ring, pyrazole ring, indazole ring, imidazole ring, pyridine ring, quinoline ring, isoquinoline ring and the like. Among these, a 5- to 8-membered aromatic heterocyclic ring containing 1 to 3 atoms selected from a nitrogen atom, an oxygen atom and a sulfur atom as a heteroatom is preferable, a pyrrole ring, a furan ring, a thiophene ring, an indole ring, A benzofuran ring, a benzothiophene ring, a carbazole ring, a pyrazole ring, and an indazole ring are more preferred.

R ¹¹ represents a hydrogen atom, or represents a single bond together with R ¹³ when ring A is a benzene ring and Rb is a group represented by the formula (b); and ring B together to form a fluorene ring, or may form a xanthene ring together with ring A and ring B via an oxygen atom. The ring which may be formed by R ¹¹ and R ¹³ together is preferably a fluorene ring or a xanthene ring.

p X ¹ are each independently a single bond, -O-, -S-, -C(=O)O-, -C(=O)NH-, -NHC(=O)-, or - NR ¹⁵ -- (R ¹⁵ represents a hydrogen atom, an alkyl group or an aralkyl group);
Here, R ¹⁵ is preferably a hydrogen atom, a C1-10 alkyl group or a C7-20 aralkyl group. Examples of the alkyl group include straight-chain or branched-chain C1 to Ten alkyl groups are mentioned.
Aralkyl groups include C7-16 aralkyl groups such as benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, naphthylmethyl and 1-naphthylethyl groups.

p R ¹² are each independently an aliphatic hydrocarbon group, an aliphatic hydrocarbon group substituted with an aliphatic hydrocarbon group via an oxygen atom, or an organic group represented by formula (a) indicates

However, R ¹⁶ represents a linear or branched alkylene group having 6 to 16 carbon atoms, and X ³ is an oxygen atom or —C(=O)NR ¹⁷ — (R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). A represents either a silyl group or an alkyl group to which a silyloxy group is bonded.
p represents an integer of 1-4.

As used herein, an organic group having an aliphatic hydrocarbon group is a monovalent organic group having an aliphatic hydrocarbon group in its molecular structure. The site of the aliphatic hydrocarbon group in the organic group having the aliphatic hydrocarbon group is not particularly limited, and may be present at the terminal or at any other site.
The aliphatic hydrocarbon group present in the organic group is a linear, branched or cyclic saturated or unsaturated aliphatic hydrocarbon group. A hydrogen group is preferred, a C5-50 aliphatic hydrocarbon group is more preferred, and a C8-30 aliphatic hydrocarbon group is even more preferred. Specific examples of the aliphatic hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group and the like, with alkyl groups, cycloalkyl groups and alkenyl groups being particularly preferred, and alkyl groups being more preferred. Further, a C5-30 linear or branched alkyl group, a C3-8 cycloalkyl group, a C5-30 linear or branched alkenyl group are preferred, and a C5-30 linear or branched alkyl group. , a C3-8 cycloalkyl group is more preferred, a C5-30 linear or branched alkyl group is more preferred, and a C8-30 linear or branched alkyl group is even more preferred.

Specific examples of the alkyl group include alkyl groups having 1 to 30 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group and pentyl group. , hexyl group, octyl group, decyl group, lauryl group, tridecyl group, myristyl group, cetyl group, stearyl group, arachyl group, behenyl group, tetracosanyl group, hexacosanyl group, isostearyl group, and other monovalent groups; divalent groups derived from and various steroid groups excluding hydroxyl groups and the like.
The branched alkyl group includes 2,3-dihydrophytyl group and 3,7,11-trimethyldodecyl group. When X ¹ is -NHC(=O)-, X ¹ R ¹² includes 2,2,4,8,10,10-hexamethyl-5-dodecanoic acid amide.
The alkenyl group includes monovalent groups such as vinyl group, 1-propenyl group, allyl group, isopropenyl group, butenyl group, isobutenyl group and oleyl group, and divalent groups derived therefrom.
The alkynyl group includes an ethynyl group, a propargyl group, a 1-propynyl group and the like.

The above aliphatic hydrocarbon group may be substituted with an aliphatic hydrocarbon group via an oxygen atom. Examples of the aliphatic hydrocarbon group capable of substituting an oxygen atom on the aliphatic hydrocarbon group include straight-chain or branched-chain alkoxy groups having 1 to 20 carbon atoms, alkenyloxy groups having 2 to 20 carbon atoms, and 3 carbon atoms. monovalent groups such as cycloalkyloxy groups of up to 6, divalent groups derived therefrom, and the like. Further, it may have a repeating structure in which an aliphatic hydrocarbon group substituted with an aliphatic hydrocarbon group through an oxygen atom is further substituted with an aliphatic hydrocarbon group through an oxygen atom.
Specifically, as R ¹² , 12-docosyloxy-1-dodecyl group, 3,4,5-tris(octadecyloxy)benzyl group, 2,2,2-tris(octadecyloxymethyl)ethyl group, 3,4 , 5-tris(octadecyloxy)cyclohexylmethyl group and the like.

The above aliphatic hydrocarbon group may be substituted with an organic group represented by formula (a).

(R ¹⁶ represents a linear or branched alkylene group having 6 to 16 carbon atoms, X ³ is an oxygen atom or —C(═O)NR ¹⁷ —(R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) A represents a silyl group or an alkyl group to which a silyloxy group is bonded)
The silyl group is preferably a silyl group substituted by three groups selected from linear or branched alkyl groups having 1 to 6 carbon atoms and aryl groups which may have a substituent. Here, examples of the aryl group which may have a substituent include a phenyl group and a naphthyl group.
A preferred silyl group is a silyl group substituted with three linear or branched alkyl groups having 1 to 6 carbon atoms, more preferably three linear or branched alkyl groups having 1 to 4 carbon atoms. It is a substituted silyl group. The three alkyl groups or aryl groups substituting on the silyl group may be the same or different.
In addition, as the alkyl group to which the silyloxy group is bonded, one silyloxy group substituted by three selected from linear or branched alkyl groups having 1 to 6 carbon atoms and aryl groups which may have substituents is used. A linear or branched alkyl group having 1 to 13 carbon atoms with ˜3 bonds is preferred. A preferred silyloxy group is a silyloxy group substituted with three linear or branched alkyl groups having 1 to 6 carbon atoms, more preferably three linear or branched alkyl groups having 1 to 4 carbon atoms. It is a substituted silyloxy group. The three alkyl groups or aryl groups substituted on the silyloxy group may be the same or different.
The linear or branched alkyl group having 1 to 13 carbon atoms is preferably branched, and more preferably has a quaternary carbon atom.

　p represents an integer of 1 to 4. Here, p is preferably 1-3, more preferably 1-2.

Ring A is, in addition to p X ¹ R ¹² , a halogen atom, a C1-6 alkyl group optionally substituted with a halogen atom, and a C1-6 alkoxy group optionally substituted with a halogen atom may have a substituent selected from the group consisting of
Halogen atoms include chlorine, fluorine, bromine and iodine atoms. The C1-6 alkyl group optionally substituted with a halogen atom includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. , a dichloromethyl group, a trichloromethyl group, a trifluoromethyl group, and the like. The C1-6 alkoxy group optionally substituted with a halogen atom includes a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, and a trichloromethoxy group. groups, trifluoromethoxy groups, and the like.

Ra represents a hydrogen atom or an aromatic ring optionally substituted with a halogen atom.
Here, the aromatic ring includes a C6-18 aromatic hydrocarbon ring and a C4-10 aromatic heterocyclic ring.
Specific C6-18 aromatic hydrocarbon rings include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, triphenylene ring, tetracene ring, indane ring, indene ring, fluorene ring and biphenyl ring. Among these, a benzene ring, a naphthalene ring, a phenanthrene ring, and a fluorene ring are more preferable.
The C4-10 aromatic heterocyclic ring is preferably a 5- to 10-membered heterocyclic ring containing 1 to 3 heteroatoms selected from a nitrogen atom, an oxygen atom and a sulfur atom, and specifically, pyrrole. ring, furan ring, thiophene ring, indole ring, benzofuran ring, benzothiophene ring, carbazole ring, pyrazole ring, indazole ring, imidazole ring, pyridine ring, quinoline ring, isoquinoline ring and the like. Among these, a 5- to 8-membered heterocyclic ring containing 1 to 3 atoms selected from a nitrogen atom, an oxygen atom and a sulfur atom as a heteroatom is preferable, and a pyrrole ring, a furan ring, a thiophene ring, an indole ring, and a benzofuran ring. , benzothiophene ring, carbazole ring, pyrazole ring and indazole ring are more preferred.
The aromatic ring of Ra may be substituted with 1 to 3 halogen atoms.

Rb represents a hydrogen atom, an aromatic ring optionally substituted with a halogen atom, or a group represented by the above formula (a).
q in formula (a) represents an integer of 0-4.
q is preferably 0 to 3, more preferably 1 to 3, even more preferably 1 to 2.

q X ² are each independently a single bond, -O-, -S-, -C(=O)O-, -C(=O)NH-, -NHC(=O)-, or - NR ¹⁸ — (R ¹⁸ represents a hydrogen atom, an alkyl group or an aralkyl group);
Here, R ¹⁸ is preferably a hydrogen atom, a C1-10 alkyl group or a C7-20 aralkyl group. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl and hexyl groups.
Aralkyl groups include C7-16 aralkyl groups such as benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, naphthylmethyl and 1-naphthylethyl groups.

q R ¹⁴ are independently an aliphatic hydrocarbon group, an aliphatic hydrocarbon group substituted with an aliphatic hydrocarbon group via an oxygen atom, or an organic group represented by formula (a) show.

However, R ¹⁶ represents a linear or branched alkylene group having 6 to 16 carbon atoms, and X ³ is an oxygen atom or —C(=O)NR ¹⁷ — (R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). A represents either a silyl group or an alkyl group to which a silyloxy group is attached.
Examples of the organic group represented by R ¹⁴ include the same groups as those for R ¹² above, and preferably the same groups as those for R ¹² above.

R ¹³ represents a hydrogen atom, represents a single bond together with R ¹¹ to form a fluorene ring together with ring A and ring B, or forms a xanthene ring together with ring A and ring B through an oxygen atom. may be formed.

Ring B, in addition to q X ² R ¹⁴ , further comprises a halogen atom, a C1-6 alkyl group optionally substituted with a halogen atom, and a C1-6 alkoxy group optionally substituted with a halogen atom may have a substituent selected from the group consisting of
Halogen atoms include chlorine, fluorine, bromine and iodine atoms. The C1-6 alkyl group optionally substituted with a halogen atom includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. , a dichloromethyl group, a trichloromethyl group, a trifluoromethyl group, and the like. The C1-6 alkoxy group optionally substituted with a halogen atom includes a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, and a trichloromethoxy group. groups, trifluoromethoxy groups, and the like.

Y represents a hydroxy group, a thiol group, NHR ²⁰ (R ²⁰ represents a hydrogen atom, an alkyl group or an aralkyl group) or a halogen atom.
Here, R ²⁰ is preferably a hydrogen atom, a C1-10 alkyl group or a C7-20 aralkyl group. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl and hexyl groups.
Aralkyl groups include C7-16 aralkyl groups such as benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, naphthylmethyl and 1-naphthylethyl groups.

Among the compounds of formula (I) above, specific examples of preferred carriers for liquid-phase peptide synthesis include compounds represented by the following formulas (7), (20), or (21). As one of them, a compound represented by Formula (7) can be used (Patent Documents 13 and 14).

(wherein Yb is --CH ₂ OR ³⁴ (wherein R ³⁴ represents a hydrogen atom, a halogenocarbonyl group, an active ester carbonyl group or an active ester sulfonyl group), --CH ₂ NHR ³⁵ (wherein R ³⁵ represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or an aralkyl group), a halogenomethyl group, a formyl group, or an oxime, and R ²¹ , R ²² , R ²³ , R ²⁴ and at least one of R ²⁵ represents a group represented by formula (8), the remainder represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms;

R ²⁶ represents a linear or branched alkylene group having 6 to 16 carbon atoms;
X ³ represents O or CONR ³⁶ (wherein R ³⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms);
A is represented by formula (9), (10), (11), (12), (13), (14), (15), (16), (17), (18) or (19) indicates a group.

(Here, R ²⁷ , R ²⁸ and R ²⁹ are the same or different and represent a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group which may have a substituent; ³⁰ represents a single bond or a linear or branched alkylene group having 1 to 3 carbon atoms, and R ³¹ , R ³² and R ³³ each represent a linear or branched alkylene group having 1 to 3 carbon atoms) )

In addition, the compound represented by formula (20) can be used as a carrier for liquid-phase peptide synthesis (Patent Documents 15, 16, 19).

(wherein X ⁴ is —OR ⁵¹ (wherein R ⁵¹ represents a hydrogen atom, an active ester carbonyl group or an active ester sulfonyl group), —NHR ³⁵ , azide, halogen, isocyanate, together with X ⁵ =N-OH or =O, and when X ⁴ is -OR ⁵¹ , -NHR ³⁵ , azide or halogen, X ⁵ is a hydrogen atom or a linear or branched alkyl or alkenyl group having 1 to 4 carbon atoms , or represents a cycloalkyl group, and when X ⁴ is isocyanate, X ⁵ represents a linear or branched alkyl group or alkenyl group having 1 to 4 carbon atoms, or a cycloalkyl group;
At least one of R ⁴¹ to R ⁵⁰ represents a group represented by formula (2), and the remainder represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. indicate;
when X ⁴ is —OR ⁵¹ , —NHR ³⁵ , azide or halogen, and X ⁵ is a hydrogen atom, or when X ⁴ and X ⁵ together are =O, R ⁴⁵ and R ⁴⁶ are oxygen atoms to form a xanthene ring)

In addition, the compound represented by formula (21) can be used as a carrier for liquid-phase peptide synthesis (Patent Documents 17 and 18).

(In the formula, X ⁶ represents a hydroxy group or a halogen atom, at least one of R ⁶¹ to R ⁷⁵ represents a group represented by formula (2), and the remainder are hydrogen atoms, halogen atoms, and 1 carbon atom. 4 alkyl group ^or alkoxy group having 1 to ⁴ carbon atoms; may form)

Regarding steps b and c, Patent Documents 7 to 25, etc. can be referred to, and can be carried out by methods well known to those skilled in the art. Instead of step c, as a method for separating the peptide bound to the carrier for liquid-phase peptide synthesis, the difference in solubility in a solvent between the peptide bound to the carrier for liquid-phase peptide synthesis and unnecessary components is used to purify by solidification. It is also possible to

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
In addition, the amino acid not described as D-form is assumed to be L-form.

Example 1 Synthesis of Fmoc-hArg(Et) ₂ (Boc) ₂ -OH

(hereinafter, Cbz-Lys-OH, EtNH-C(SO ₃ H)=NEt, Cbz-hArg(Et) ₂ -OH, Cbz-hArg(Et) ₂ (Boc) ₂ -OH, H-hArg(Et) ₂ (Boc) ₂ -OH, Fmoc-OSu and Fmoc-hArg(Et) ₂ (Boc) ₂ -OH represent the structures in the above reaction formula, where Cbz-hArg(Et) ₂ (Boc) ₂ -OH , H-hArg(Et) ₂ (Boc) ₂ -OH, and Fmoc-hArg(Et) ₂ (Boc) ₂ -OH each represent a mixture of three isomers in the reaction formula.)

Example (1-a)
Cbz-Lys-OH 2.00 g (7.13 mmol) was dissolved in a mixed solution of water 7.13 mL, acetonitrile 7.13 mL, 20% sodium hydroxide aqueous solution (20% NaOHaq.) 1.28 mL, EtNH-C ( SO ₃ H)=NEt 2.25 g (12.5 mmol) was added and stirred at room temperature. Then 20% NaOHaq. 301 μL was added in small portions and stirred at room temperature for 22 hours and 30 minutes while maintaining the pH of the reaction solution at 8.0 to 12.8. Acetonitrile 7.13 mL, ethyl acetate 18.8 mL, 6N HClaq. 800 μL was added, liquid separation was performed, and the organic layer was recovered. 14.3 mL of acetonitrile and 18.8 mL of ethyl acetate were added to the aqueous layer, the layers were separated, and the organic layer was recovered. Again, 14.3 mL of acetonitrile and 18.8 mL of ethyl acetate were added to the resulting aqueous layer, and the layers were separated to recover the organic layer. The organic layers obtained by liquid separation three times in total were combined and concentrated under reduced pressure. 30.0 mL of ethanol was added to the residue, and the mixture was concentrated under reduced pressure. After adding 30.0 mL of ethanol to the obtained residue and stirring, the precipitated solid was removed by Celite filtration. The filtrate was concentrated under reduced pressure, diisopropyl ether was added to the residue, and the mixture was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (ethyl acetate:methanol=1:1.5→1:3) to obtain 1.82 g of Cbz-hArg(Et) ₂ -OH.
ESIMS (M/z) 379.3 (M+H) ⁺

Example (1-b)
6.57 g (30.1 mmol) of di-tert-butyl dicarbonate was dissolved in 30.1 mL of 1,4-dioxane. To this solution was added 7.53 mL of 1,4-dioxane and 5N NaOHaq. Cbz-hArg(Et) ₂ -OH 1.71 g (4.52 mmol) dissolved in 15.1 mL was added dropwise and stirred at room temperature for 17 hours. 126 mL of dichloromethane, 93.0 mL of water, and 3.70 mL of acetic acid were added and separated. The obtained organic layer was washed with 93.0 mL of saturated saline. 22.0 g of anhydrous sodium sulfate was added to the obtained organic layer, and the mixture was sufficiently stirred and then filtered, and the filtrate was concentrated under reduced pressure. 31.0 mL of heptane was added to the residue and concentrated under reduced pressure, and 30 mL of diisopropyl ether was added to the residue and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (heptane:ethyl acetate=2:1→ethyl acetate:methanol=4:1) to give 2.16 g of Cbz-hArg(Et) ₂ (Boc) ₂ -OH. Obtained.
ESIMS (m/z) 579.5 (M+H) ⁺ (mixture of 3 isomers)

Example (1-c)
2.09 g (3.61 mmol) of Cbz-hArg(Et) ₂ (Boc) ₂ -OH was dissolved in 20.9 mL of methanol, and 0.139 g of 5% Pd/C (wet with ca. 55% water) was added. under a hydrogen atmosphere at room temperature for 2 hours. The reaction solution was filtered through celite, and the filtrate was washed with 20 mL of methanol. The obtained filtrate was concentrated under reduced pressure and then dried under reduced pressure to obtain 1.28 g of H-hArg(Et) ₂ (Boc) ₂ -OH.
ESIMS (m/z) 445.4 (M+H) ⁺ (mixture of 3 isomers)

Example (1-d)
0.427 g (5.08 mmol) of sodium bicarbonate and 1.13 g (2.54 mmol) of H-hArg(Et) ₂ (Boc) ₂ -OH were added to 9.99 mL of water, dissolved, and cooled to 5°C. 0.900 g (2.67 mmol) of Fmoc-OSu dissolved in 9.99 mL of 1,4-dioxane was added dropwise to this solution, and the mixture was stirred at 5° C. for 1 hour and 5 minutes. The temperature was raised to room temperature, and the mixture was stirred for 3 hours and 25 minutes. 20.0 mL of water, 50.0 μL of acetic acid, and 15.0 mL of ethyl acetate were added to the reaction liquid, and the layers were separated to recover the organic layer. 15.0 mL of ethyl acetate was added to the obtained aqueous layer, and the layers were separated, the organic layer was recovered, and the same liquid separation operation was further performed twice. The organic layers obtained by a total of four liquid separation operations were mixed, 15.3 g of anhydrous sodium sulfate was added, the mixture was thoroughly stirred, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (heptane:ethyl acetate=1:1→1:2) to obtain 0.261 g of Fmoc-hArg(Et) ₂ (Boc) ₂ -OH.
ESIMS (m/z) 667.5 (M+H) ⁺ (mixture of 3 isomers)

Example 2 Synthesis of Fmoc-D-hArg(Et) ₂ (Boc) ₂ -OH

(hereinafter, Cbz-D-Lys-OH, Cbz-D-hArg(Et) ₂ -OH, Cbz-D-hArg(Et) ₂ (Boc) ₂ -OH, HD-hArg(Et) ₂ (Boc ) ₂ -OH, Fmoc-D-hArg(Et) ₂ (Boc) ₂ -OH represent structures in the reaction formula, where Cbz-D-hArg(Et) ₂ (Boc) ₂ -OH, HD -hArg(Et) ₂ (Boc) ₂ -OH and Fmoc-D-hArg(Et) ₂ (Boc) ₂ -OH each represent a mixture of three isomers in the reaction formula.)

Example (2-a)
4.57 g of Cbz-D-hArg(Et) ₂ -OH was obtained from 4.80 g of Cbz-D-Lys-OH in the same manner as in Example (1-a).
ESIMS (m/z) 379.3 (M+H) ⁺

Example (2-b)
5.23 g of Cbz-D-hArg(Et) ₂ (Boc) ₂ -OH was obtained from _3.93 g of Cbz-D-hArg(Et) 2 -OH in the same manner as in Example (1-b).
ESIMS (m/z) 579.4 (M+H) ⁺ (mixture of 3 isomers)

Example (2-c)
HD-hArg(Et) ₂ (Boc) ₂ -OH 3.35 g was obtained from 4.89 g of Cbz-D-hArg(Et) ₂ (Boc) ₂ -OH in the same manner as in Example (2-c). got
ESIMS (m/z) 445.4 (M+H) ⁺ (mixture of 3 isomers)

Example (2-d)
Crude Fmoc-D-hArg(Et) ₂ (Boc) ₂ -OH was obtained from 3.00 g of HD-hArg(Et) ₂ (Boc) ₂ -OH in the same manner as in Example (1-d). got The resulting crude product was purified by silica gel column chromatography (heptane:ethyl acetate=2:1→1:1→1:2) to obtain Fmoc-D-hArg(Et) ₂ (Boc) ₂ -OH1. 90 g was obtained.
ESIMS (m/z) 667.6 (M+H) ⁺ (mixture of 3 isomers)

Reference example 1
Synthesis of Fmoc-NH(D2-STag)

(O = (D2-Stag), OH (D2-STag), and Fmoc-NH (D2-STag) represent structures in the reaction formula.)

Reference example (a)
O = (D2-STag) (manufactured by Sekisui Medical Co., Ltd.) 41.4 g (47.7 mmol) was dissolved in a mixed solution of 228 mL of toluene and 36.0 mL of methanol, and 2.16 g (57.2 mmol) of sodium borohydride was added. and stirred at room temperature for 3 hours. The reaction solution was separated and washed three times with 83.0 mL of water. 20.0 g of anhydrous sodium sulfate was added to the obtained organic layer, and the mixture was sufficiently stirred and then filtered to obtain a toluene solution containing OH (D2-STag).

Reference example (b)
13.7 g (57.2 mmol) of 9-fluorenylmethylcarbamate and 1.80 g (14.3 mmol) of oxalic acid dihydrate are added to the toluene solution obtained in the previous step, and stirred at 80° C. for 3 hours. bottom. The reaction solution was cooled to room temperature, 414 mL of methanol:water=9:1, and 414 mL of heptane were added and separated. The resulting organic layer was washed once with 207 mL of a 5% aqueous sodium carbonate solution (5% Na ₂ CO ₃ aq.) and three times with 414 mL of methanol:water=9:1. The obtained organic layer was concentrated under reduced pressure, 83.0 mL of tetrahydrofuran was added to the residue, and the mixture was concentrated under reduced pressure. The residue was dissolved in 62 mL of tetrahydrofuran and added dropwise to 830 mL of methanol. The precipitated solid was collected by filtration and dried under reduced pressure to obtain 45.5 g of Fmoc-NH(D2-STag).
ESIMS (m/z) 1107.9 (M+ _NH4 ) ⁺

Example 3
Synthesis of H-hArg ₍ Et) ₂ (Boc) ₂ -Pro-D-Ala-NH(D2-STag) using Fmoc-hArg(Et) ₂ (Boc) 2 -OH

(NH ₂ (D2-STag), HD-Ala-NH (D2-STag), H-Pro-D-Ala-NH (D2-STag), H-hArg(Et) ₂ (Boc) ₂ -Pro -D-Ala-NH(D2-STag) represents the structure in the reaction scheme, and Fmoc-L-hArg(Et) ₂ (Boc) ₂ -OH is one of the three isomers in the reaction scheme. indicates a mixture, and * in the structure of R' indicates the point of attachment.)

Example (3-a)
Fmoc-NH(D2-STag) 2.00 g (1.83 mmol) was dissolved in cyclopentyl methyl ether (CPME) 29.3 mL, N,N-dimethylformamide (DMF) 7.33 mL, dimethyl sulfoxide (DMSO)2. 0.542 g (3.04 mmol) of sodium 3-mercapto-1-propanesulfonate (MPS) dissolved in 55 mL and an additional 0.111 g (0.62 mmol) of MPS were added in the solid state to give 2,3,4,6 ,7,8,9,10-Octahydropyrimidol[1,2-a]azepine (DBU) 0.548 mL (3.67 mmol) was added, and the mixture was stirred at room temperature for 1 hour and 35 minutes. Cool to 8° C., add 0.319 mL (1.83 mmol) of N,N-diisopropylethylamine (DIPEA), 3.67 mL (3.67 mmol) of 1N sulfuric acid, 24.2 mL of water, and 1.00 mL of CPME, and separate the liquids. bottom. 4.55 mL of DMF and 6.07 mL of 50% aqueous solution of dipotassium hydrogen phosphate (50% K ₂ HPO ₄ aq.) were added to the obtained organic layer, washed by separation, and mixed with NH ₂ (D2-STag). I got the liquid.

Example (3-b)
To the resulting mixture, 1.00 mL of CPME, 8.30 mL of DMF, 0.725 g (2.20 mmol) of Fmoc-D-Ala-OH.H ₂ O, 1.28 mL (7.33 mmol) of DIPEA, and 0.28 mL of COMU were added. 942 g (2.20 mmol) was added and stirred at room temperature for 45 minutes. 44.0 μL (0.444 mmol) of 2-(2-Aminoethoxy)ethanol (AEE) was added and stirred at room temperature for 15 minutes. Add 0.501 g (2.81 mmol) of MPS dissolved in 2.35 mL of DMSO, 0.284 g (1.59 mmol) of solid MPS, cool to 10° C., add 1.43 mL (9.54 mmol) of DBU, add 1 Stirred for 20 minutes. 11.5 mL (11.5 mmol) of 1N sulfuric acid, 20.2 mL of water, and 0.796 mL of CPME were added and separated. DMF 5.10 mL, 50% K ₂ HPO ₄ aq. 6.80 mL was added, and washing was performed by liquid separation to obtain a mixed solution containing HD-Ala-NH (D2-STag).

Example (3-c)
To the resulting mixture, CPME 2.20 mL, DMF 8.30 mL, Fmoc-Pro-OH.H ₂ O 0.782 g (2.20 mmol), DIPEA 1.28 mL (7.33 mmol), COMU 0.942 g ( 2.20 mmol) was added and stirred at room temperature for 50 minutes. 44.0 μL (0.444 mmol) of AEE was added, and the mixture was stirred at room temperature for 15 minutes. Add 0.501 g (2.81 mmol) of MPS dissolved in 2.35 mL of DMSO, 0.284 g (1.59 mmol) of solid MPS, cool to 8° C., add 1.43 mL (9.54 mmol) of DBU, add 1 Stirred for 20 minutes. 11.5 mL (11.5 mmol) of 1N sulfuric acid, 20.2 mL of water, and 0.861 mL of CPME were added and separated. DMF 5.11 mL, 50% K ₂ HPO ₄ aq. 6.81 mL was added and washing was carried out to obtain a mixed solution containing H-Pro-D-Ala-NH (D2-STag).

Example (3-d)
To the resulting mixture were added 2.70 mL of CPME, 8.30 mL of DMF, and 1.47 g of Fmoc-hArg(Et) ₂ (Boc) ₂ -OH (a mixture of three isomers shown in the reaction formula) (2. 20 mmol), 1.28 mL (7.33 mmol) of DIPEA, and 0.942 g (2.20 mmol) of COMU were added and stirred at room temperature for 50 minutes. 44.0 μL (0.444 mmol) of AEE was added, and the mixture was stirred at room temperature for 15 minutes. Add 0.501 g (2.81 mmol) of MPS dissolved in 2.35 mL of DMSO, 0.284 g (1.59 mmol) of solid MPS, cool to 8° C., add 1.43 mL (9.54 mmol) of DBU, add 1 Stirred for 50 minutes. 11.5 mL (11.5 mmol) of 1N sulfuric acid, 20.3 mL of water, and 0.950 mL of CPME were added and separated *1. DMF 5.12 mL, 50% K ₂ HPO ₄ aq. 6.83 mL was added, and washing was performed by separation to obtain a mixed solution containing H-hArg(Et) ₂ (Boc) ₂ -Pro-D-Ala-NH(D2-STag).
ESIMS (m/z) 1463.7 (M+H) ⁺ (mixture of 3 isomers)
* 1 HPLC purity of target in organic layer: 76.2%

HPLC analysis conditions Column: YMC-Pack Pro C18, S-5 μm, 12 nm, 250 mm×4.6 mmI. D.
Mobile phase A: 500 mM sodium perchlorate aq.
Mobile phase B: THF
Flow rate: 1.0 mL/min
Column temperature: 45°C
Detection wavelength: 280 nm
Gradient conditions: 75% B (0 min) → 90% B (10 min) → 90% B (20 min) → 75% B (21 min) → 75% B (33 min)

Comparative example 1
Synthesis of H-hArg(Et) ₂ -Pro-D-Ala-NH(D2-STag) using Fmoc-hArg(Et) ₂ -OH.HCl

(Fmoc-hArg(Et) ₂ -OH.HCl and H-hArg(Et) ₂ -Pro-D-Ala-NH(D2-STag) represent structures in the reaction formula.)

Comparative examples (1-a), (1-b), (1-c)
H-Pro-D-Ala-NH(D2-STag) was prepared from 2.00 g (1.83 mmol) of Fmoc-NH(D2-STag) in the same manner as in Examples 3-a, 3-b, and 3-c. A mixture containing

Comparative example (1-d)
To the resulting mixture, 2.60 mL of CPME, 8.30 mL of DMF, 1.11 g (2.20 mmol) of Fmoc-hArg(Et) ₂ -OH.HCl, 1.28 mL (7.33 mmol) of DIPEA, and 0.28 mL of COMU were added. 942 g (2.20 mmol) was added and stirred at room temperature for 50 minutes. 44.0 μL (0.444 mmol) of AEE was added, and the mixture was stirred at room temperature for 15 minutes. Add 0.501 g (2.81 mmol) of MPS dissolved in 2.35 mL of DMSO, 0.284 g (1.59 mmol) of solid MPS, cool to 8° C., add 1.43 mL (9.54 mmol) of DBU, add 1 Stirred for 50 minutes. 11.5 mL (11.5 mmol) of 1N sulfuric acid, 20.3 mL of water, and 0.950 mL of CPME were added to attempt to separate the liquids.
ESIMS (m/z) 1263.5 (M+H) ⁺
*2 HPLC purity of target in emulsion: 10.4%
HPLC analysis conditions: same as in Example (3-d)

1 and 2 show the state of liquid separation in *1 of Example (3-d) and *2 in Comparative Example (1-d). In Example (3-d) shown in FIG. 1, the interface between the organic layer and the aqueous layer was clear, and the liquid-liquid separation was good. On the other hand, in the comparative example (1-d) shown in FIG. 2, the entire inside of the separating funnel became an emulsion, and the emulsion did not disappear even after standing at room temperature for 25 minutes, and the organic layer and the aqueous layer could be separated. I didn't.
Table 1 shows the results of Example 3 and Comparative Example 1.
In Example 3 using Boc-protected Fmoc-hArg(Et) ₂ (Boc) ₂ -OH of the present invention, liquid separation was good and the purity of the target product was as high as 76.2%. We were able to synthesize a peptide with On the other hand, in Comparative Example 1 using Fmoc-hArg(Et) ₂ -OH.HCl, which was only proton-protected instead of the Boc group, liquid separation was not possible, and the purity of the target product in the emulsion was 10. It was remarkably low at 4%.

From the above results, compared with the case of using a proton-protected arginine derivative of the prior art, the case of using the Boc-protected arginine derivative of the present invention is superior in the liquid-liquid synthesis reaction in the liquid-phase peptide synthesis reaction. It was found that the separation was good and a peptide of higher purity could be obtained.

Claims (7)

An arginine derivative represented by the following formula (1), (2) or (3) or a salt thereof.

(wherein R ¹ and R ² are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A represents a hydrogen atom or a protective group for an amino group;
R ³ and R ⁴ represent a hydrogen atom or a Boc group, either one or both of which is a Boc group,
R ⁵ and R ⁶ represent a hydrogen atom or a Boc group, one or both of which is a Boc group,
R ⁷ and R ⁸ represent a hydrogen atom or a Boc group, one or both of which is a Boc group,
n is an integer of 1 to 6 (except when n is 3, R ¹ and R ² are hydrogen atoms or methyl groups, and R ³ to R ⁸ are Boc groups); The arginine derivative or its salt according to claim 1, wherein n in formula (1), (2) or (3) is 4. The arginine derivative or salt thereof according to claim 1, wherein in formula (1), (2) or (3), A is a hydrogen atom, an Fmoc group, or a Cbz group. 2. The arginine derivative or salt thereof according to claim 1, wherein in formula (1), (2) or (3), ^R1 and ^R2 are ethyl groups. The arginine derivative or salt thereof according to claim 1, wherein in formula (1), (2) or (3), A is an Fmoc group. 2. The arginine derivative or salt thereof according to claim 1, wherein in formula (1), (2) or (3), R ³ to R ⁸ are Boc groups. A liquid-phase peptide synthesis method using the arginine derivative or salt thereof according to any one of claims 1 to 6.

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