WO2023127331A1

WO2023127331A1 - Peptide production method, protecting group removing method, removing agent, and benzyl compound

Info

Publication number: WO2023127331A1
Application number: PCT/JP2022/042265
Authority: WO
Inventors: 宗江葛西; 康嗣下田; 誠佐藤; 杏梨上原; 圭介松浦
Original assignee: 株式会社トクヤマ
Priority date: 2021-12-27
Filing date: 2022-11-14
Publication date: 2023-07-06
Also published as: JP2023097449A; JP7356607B2; JP2023166447A; JP7338088B2; JP2023097442A

Abstract

One problem to be addressed by the present invention is to provide: a protecting group removing method capable of suppressing generation of double-hit bodies and diketopiperazine, easily scavenging a fulvene backbone-including compound that is a by-product potentially generated after deprotecting a protecting group having a fluorine backbone, and easily isolating a scavenged body of the by-product; a peptide production method comprising a step for removing a protecting group; and a protecting group removing agent. A peptide production method according to one aspect of the present invention comprises: a step for bringing, in an organic solvent, a scavenger represented by formula (Z1) into contact with an amino group-containing compound in which the N-terminal is protected by a protecting group having a fluorine backbone, to obtain a scavenged body in which the scavenger is bound to a by-product having a fulvene backbone derived from the protecting group; and a step for separating the obtained scavenged body from the organic solvent.

Description

Peptide production method, protective group removal method, removal agent, and benzyl compound

One aspect of the present invention relates to a novel benzyl compound, particularly to a novel benzyl compound used in a peptide synthesis method using a tag synthesis method, and a peptide synthesis method using the benzyl compound. Another aspect of the present invention is to efficiently capture a by-product having a fulvene skeleton generated during the deprotection reaction of a protective group having a fluorene skeleton in liquid-phase peptide synthesis, and to efficiently remove the by-product by washing. It also relates to methods, methods of producing peptides using the methods, and the like.

Conventionally, solid phase peptide synthesis method (SPPS method) and liquid phase peptide synthesis method (LPPS method) are known as methods for synthesizing peptides. The solid-phase peptide synthesis method purifies the peptide by filtering out unnecessary substances in the condensation reaction of amino acids, so that the peptide can be synthesized relatively easily, and therefore, it is suitable for the synthesis of long-chain peptides. However, the solid-phase peptide synthesis method uses an excessive amount of amino acids and washing solvents, resulting in a high synthesis cost and is considered unsuitable for large-scale peptide synthesis.

In contrast, the liquid-phase peptide synthesis method is used for large-scale peptide synthesis. However, in the liquid-phase peptide synthesis method, the elongation of the peptide chain tends to become difficult when the peptide chain becomes long, and there is a problem in long-chain peptide synthesis.

Therefore, a synthesis method that combines the advantages of the solid-phase peptide synthesis method and the liquid-phase peptide synthesis method described above is being studied (see Patent Document 4, for example). The synthesis method is a method of synthesizing a peptide using a protective group soluble in a solution (a C-terminal protective group of an amino acid, hereinafter also referred to as a "tag"). A peptide is synthesized by binding amino acids to the tag possessed and sequentially repeating the elongation reaction. According to this synthetic method, by solidifying (for example, crystallizing) only the peptide bound to the tag at each elongation step, the solidified substance can be easily separated and purified.

In addition, there is also known a method of selectively dissolving only the dissolved tag-bound peptide component in a specific phase along with phase separation of a liquid, thereby separating it from other unnecessary components (hereinafter referred to as Also referred to as a “liquid phase tagging method.” See, for example, Patent Documents 1 to 9 and Non-Patent Documents 1 to 3.). According to this method, unnecessary components can be separated without solidification, which contributes to speeding up and simplification of the reaction process.

By the way, in the liquid-phase tagging method, since it is continuously carried out in one pot in an organic solvent, it is desirable to use an organic solvent that has a specific gravity of 1 or less and is immiscible with the aqueous layer. In addition to this, from the viewpoint of environmental protection, it is desirable to use a non-halogen solvent as the organic solvent.

However, a benzyl alcohol tag having linear alkyl groups each having 18 carbon atoms at the 3, 4, and 5 positions disclosed in Patent Document 4, and a tag at the 3 and 5 positions disclosed in Patent Document 2 In addition, the benzyl alcohol tags each having a linear alkyl chain of 22 carbon atoms have low solubility in organic solvents that satisfy the above conditions, and thus only precipitate from the reaction system during peptide synthesis. Moreover, it was often difficult to separate and purify the compound after the reaction.

In view of this situation, tags with high solubility in organic solvents and high hydrophobicity have been developed as tags for use in the liquid-phase tagging method (see Patent Documents 3 and 6, for example). For example, Patent Document 3 describes an organic group having at least one aliphatic hydrocarbon group having one or more branched chains, a total number of branched chains of 3 or more, and a total carbon number of 14 or more and 300 or less. Branched chain-containing aromatic compounds having substituents are disclosed.

In addition, Patent Document 6 discloses a benzyl compound having a group containing a -O-Si- structure at its terminal. The benzyl compound described in Patent Document 6 is highly soluble in organic solvents and can be effectively used for liquid phase synthesis.

By the way, in the liquid-phase peptide synthesis method such as the liquid-phase tagging method, the technique of using the Fmoc group as an amino group-protecting group of amino acids is often used. When the Fmoc group is deprotected with a base, a by-product derived from the Fmoc group, dibenzofulvene (DBF), is produced. In order to remove this, a technique is known in which a reagent for removing DBF is used, and an adduct of DBF and a removing reagent (hereinafter sometimes abbreviated as DBF-capture) is removed by liquid separation washing.

For example, Patent Document 1 describes a method in which a thiol-containing carboxylic acid or a thiol-containing sulfonic acid is added during deprotection of an Fmoc group to generate a DBF-trapper, which is then removed by washing with an alkaline solution.

However, in this method, the thiol-containing carboxylic acid added as a scavenger reacts with the amino acid to produce a thioester. Since this thioester is an active ester, it may react with the amino group generated after removing Fmoc to form a double hit product. In addition, when the peptide sequence contains a cysteine residue in particular, the capture of DBF with a thiol compound reacts with the thiol structure at the side chain site of the cysteine residue contained in the peptide sequence, producing other byproducts. there is a risk of

In contrast, methods have been proposed to suppress the formation of double-hit compounds due to the reaction between a thioester and the amino group of a peptide whose Fmoc group has been deprotected (see, for example, Patent Document 2). In Patent Document 2, DBF generated in the deprotection of the Fmoc group is reacted with a divalent or higher water-soluble amine (for example, N-methylpiperazine) to obtain a DBF-captured product, which is then removed by acidic liquid separation washing. method is described.

In addition, Patent Document 9 and Non-Patent Document 4 disclose that the N-terminal Fmoc group is deprotected under basic conditions in the presence of a reagent such as diethylamine.

Japanese Patent No. 6136934 Japanese Patent No. 6703668 Japanese Patent No. 5929756 Japanese Patent Application Laid-Open No. 2000-44493 Japanese Patent No. 7063408 Japanese Patent No. 6116782 Japanese Patent No. 6703669 Japanese Patent No. 5768712 Japanese Patent No. 5201764 WO2019/069978

However, the branched chain-containing aromatic compound described in Patent Document 3 requires an expensive noble metal reduction catalyst such as platinum-carbon to produce the branched chain, so when applied to mass production, the cost increases. Therefore, there is room for improvement. In addition, the benzyl compound described in Patent Document 6 has a possibility that the O—Si bond is cut under conditions such as acidic liquid separation, resulting in considerable decomposition, and there is room for improvement (see also Non-Patent Document 5). see).

In view of the above circumstances, the development of a tag that can be used in the liquid phase tagging method with a structure other than a branched chain structure or a structure containing an O-Si bond has been desired.

In addition, according to the method described in Patent Document 2, a divalent or higher water-soluble amine is used, and there are operational problems such as the need to use a large amount of acid for neutralization. In addition, water-soluble divalent amines represented by N-methylpiperazine and diethylamine used in Patent Document 10 and Non-Patent Document 4 have sufficient basicity. Therefore, when a water-soluble divalent amine is added for the purpose of inactivating amino acid active esters generated from surplus amino acids and condensing agents during the condensation reaction, an unintended deprotection reaction of the Fmoc group may proceed. There is As a result, other side reactions such as the formation of diketopiperazine may proceed.

Accordingly, one of the objects of the present invention is to solve the above problems and improve the solubility of the tag in organic solvents so that it can be precipitated or insolubilized during the peptide synthesis or during liquid separation after the reaction. The object of the present invention is to provide a tag that does not contain a soluble tag, a method for producing the same, and a method for synthesizing a peptide using the tag.

Therefore, one of the objects of the present invention is to suppress the formation of double-hit compounds and diketopiperazines, and to facilitate production of a compound having a fulvene skeleton, which is a by-product that can be generated after deprotection of a protective group having a fluorene skeleton. It is an object of the present invention to provide a method for removing a protective group, which enables easy separation of the trapped substance from the by-product, a method for producing a peptide comprising the step of removing the protective group, and an agent for removing the protective group. .

The present inventors have made intensive studies to solve the above problems, and found that an aromatic ring compound having a substituent, or an alkyl group and an aralkyl group are introduced into a benzene ring having a benzyl alcohol via an oxyarene group. The present inventors have found that a benzyl compound that is highly soluble in an organic solvent and highly hydrophobic can be provided, and completed one embodiment of the present invention.

That is, the benzyl compound according to one aspect of the present invention has the following formula (X1):

[In the formula,
m Q ¹ and Q ² are each an oxygen atom,
m R ¹ are each independently an alkylene group,
m R ² are each independently an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aryl group,
k R ³ are each independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom,
X is a hydroxyl group,
m is an integer of 2 or 3,
k represents an integer from 0 to (5-m). ]
is a benzyl compound (X1) represented by

In addition, the present inventors found that by using a highly hydrophobic tag in addition to being highly soluble in an organic solvent, peptides can be synthesized more uniformly in an organic solvent that is immiscible with the aqueous layer. Therefore, when unnecessary substances are removed by liquid separation through the aqueous layer after the reaction, the peptide bound to the tag does not precipitate or become insoluble, and the loss of the peptide bound to the tag to the aqueous layer is suppressed. Based on the idea that it might lead to an improvement in yield, the inventors conducted intensive studies.

However, as a result, surprisingly, the higher the hydrophobicity, the more suitable it is for liquid separation of long-chain peptides. , obtained a new finding that a tag having a certain level or less of hydrophobicity is suitable, and completed the present invention based on this finding.

That is, the benzyl compound according to one aspect of the present invention has the following formula (Y1):

[In the formula,
m Q's each represent an oxygen atom,
m R ¹ are each independently represented by the following formula (YA):

(In the formula,
* indicates the binding position,
R ^1a , R ^1b , R ^1c , R ^1d and R ^1e each independently represent a hydrogen atom or an alkyl group,
n ₁ represents an integer of 0 to 6, and when n ₁ is 1 or more, the repeating unit shown in parentheses to which n ₁ is attached is an alkylene group,
n ₂ represents an integer of 0 or more and 6 or less, and when n ₂ is 1 or more, the repeating unit shown in parentheses to which n ₂ is attached is an alkylene group,
However, at least two or more of R ^1a , R ^1b , R ^1c and R ^1d are hydrogen atoms. )
is a group represented by
k R ² each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom;
X represents a hydroxyl group,
m represents an integer of 2 or 3,
k represents an integer of 0 or more (5-m) or less,
At least one of m [QR ¹ ] is substituted at the meta position with respect to the substituent containing X. ]
is a benzyl compound (Y1) represented by

In view of the above problems, the present inventors have made intensive studies and found that, among cyclic amines, a specific cyclic amine containing only one nitrogen atom in particular is used as a scavenger to obtain a fluorene skeleton such as an Fmoc group. Capturing a by-product having a fulvene skeleton such as DBF generated in the deprotection reaction of a protecting group having and separating the trapped body with the by-product from the reaction system can easily remove the by-product and completed one aspect of the present invention.

That is, the method for producing a peptide according to one aspect of the present invention is
In an organic solvent, an amino group-containing compound protected with a protective group having a fluorene skeleton at the N-terminus is brought into contact with a scavenger represented by the following formula (Z1) to obtain a compound having a fulvene skeleton derived from the protective group. obtaining a capturing body in which the by-product and the capturing agent are bound;
a step of separating the captured body obtained from the organic solvent;
including,
It is a peptide manufacturing method.

In the formula (Z1),
N is a nitrogen atom,
H is a hydrogen atom,
X is a divalent group represented by —CH ₂ —, —O—, —S—, or —(SO ₂ )—;
n ₁ R ^1a , n ₁ R ^1b , n ₂ R ^2a , n ₂ R ^2b , n ₃ R ^3a , and n ₃ R ^3b are each independently H , —OH, —OR (R is an alkyl group), —SH, —SR (R is as defined for —OR above.), —(SO ₂ )H, or —(SO ₂ ) A monovalent group represented by R (R is the same as that of -OR above),
R ^2a or R ^2b and R ^3a or R ^3b may be bonded to each other to form a ring together with the carbon atoms to which they are bonded,
n ₁ , n ₂ and n ₃ are each independently 1 or 2;
m is an integer of 0 or 1;

Further, a method for removing a protecting group according to one aspect of the present invention comprises, in an organic solvent, an amino group-containing compound whose N-terminus is protected with a protecting group having a fluorene skeleton, and a scavenger represented by the following formula (Z1): and a step of contacting with to obtain a capturing body in which a by-product having a fulvene skeleton derived from the protecting group and the capturing agent are bound;
a step of separating the captured body obtained from the organic solvent;
including,
A method for removing protecting groups.

In addition, the remover according to one aspect of the present invention is an agent for removing a protecting group having a fluorene skeleton, containing a scavenger represented by the following formula (Z1) and a basic deprotecting agent.

According to one aspect of the present invention, there is provided a benzyl compound that has improved solubility in an organic solvent and that can be easily separated and purified after a peptide condensation reaction by liquid-liquid layer separation. can be done.

In addition, according to one aspect of the present invention, DBF can be easily captured and the DBF-captured body can be easily removed. In addition, since the cyclic amine used in the present invention has low basicity, unintended deprotection of the Fmoc group can be suppressed, and the progress of side reactions can be suppressed.

[Embodiment 1]
[Benzyl compound]
The benzyl compound according to Embodiment 1 of the present invention has the following formula (X1)

is a benzyl compound (X1) represented by

m represents the number of substituents (-[Q ¹ -R ¹ -Q ² -R ² ]). m is an integer of 2 or 3; When m is 2, the substituents (-[Q ¹ -R ¹ -Q ² -R ² ]) are preferably present at the 3- and 5-positions or at the 2- and 4-positions. In this case, the two substituents (-[Q ¹ -R ¹ -Q ² -R ² ]) are more preferably present at the 2- and 4-positions. When m is 3, they are preferably present at adjacent positions. In this case, the three substituents (-[Q ¹ -R ¹ -Q ² -R ² ]) are more preferably present at the 3-, 4- and 5-positions.

k represents the number of substituents (-R ³ ). k is an integer of 0 or more and (5-m) or less. Specifically, when m is 2, k is an integer of 0 or more and 3 or less, and when m is 3, k is an integer of 0 or more and 2 or less.

m Q ¹ and Q ² each represent an oxygen atom.
X represents a hydroxyl group.

Each of the m R ¹ 's is independently an alkylene group. For example, R ¹ is a linear or branched alkylene group having 2 to 16 carbon atoms. The number of carbon atoms in the alkylene group is preferably 2 or more, more preferably 6 or more, and even more preferably 8 or more, from the viewpoint of improving the solubility of the peptide bound to the benzyl compound (X1) of the present invention in an organic solvent. Also, it is preferably 16 or less, more preferably 14 or less, and even more preferably 12 or less. Specific examples of the alkylene group include ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nanomethylene, decamethylene, undecamethylene, dodecamethylene, tetra decamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group and the like.

Each of m R ² is independently an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aryl group. For example, R ² is an alkyl group having 5 to 28 carbon atoms, an aralkyl group having 5 to 28 carbon atoms which may have a substituent, or an aryl group having 7 to 12 carbon atoms and having a substituent.

The number of carbon atoms in the alkyl group is preferably 5 or more, more preferably 6 or more, and 7 or more from the viewpoint of improving the solubility of the peptide bound to the benzyl compound (X1) according to the present embodiment in an organic solvent. It is more preferably 28 or less, more preferably 24 or less, and even more preferably 22 or less.

In addition, the alkyl group is a linear alkyl group (that is, an alkyl group having no branched chain) or an alkyl group having a total of 1 or 2 branched chains, and specifically, the following formula (XA ):

is preferably a group represented by

In formula (XA),
* indicates the binding position with the adjacent ^Q2 . Hereinafter, similar description may be omitted. _n1 is an integer of 0 or more and 16 or less, and _n2 is an integer of 0 or more and 16 or less. Preferably, _n1 is an integer of 0 or more and 6 or less, and _n2 is an integer of 0 or more and 13 or less.

R ^2a , R ^2b , R ^2c , R ^2d and R ^2e are each independently a hydrogen atom or an alkyl group. The alkyl group may have a substituent, and the substituent is, for example, a halogen atom such as fluorine, chlorine, bromine, or iodine. At least two or more of R ^2a , R ^2b , R ^2c and R ^2d are hydrogen atoms.

Specific examples of the groups represented by the formula (XA) include pentyl group, octyl group, isooctyl group, nonyl group, decyl group, undecyl group, dodecyl group, 1-methyl-1-dodecyl group, 1-methyl-1 -hexadecyl group, 1-ethyl-1-heptadecyl group, 1-propyl-1-decyl group, 1-butyl-1-decyl group, 2-methyl-1-dodecyl group, 2-methyl-1-hexadecyl group, 2 -butyl-1-octyl group, 2-butyl-1-dodecyl group, 2-butyl-1-octadecyl group, 2-hexyl-1-decyl group, 2-hexyl-1-dodecyl group, 2-heptyl-1- dodecyl group, 2-octyl-1-dodecyl group, 2-octyl-1-tetradecyl group, 2-decyl-1-tetradecyl group, 2-dodecyl-1-tetradecyl group, 2-dodecyl-1-hexadecyl group, 3- methyl-1-tetradecyl group, 4-ethyl-1-octyl group, 6-methyl-1-heptyl group, 9-methyl-1-dodecyl group, 12-methyl-1-tridecyl group, 15-methyl-1-hexadecyl and 2-tetradecyl-1-octadecyl groups.

Among them, the alkyl group includes pentyl group, octyl group, isooctyl group, nonyl group, decyl group, undecyl group, dodecyl group, 2-butyl-1-octyl group, 2-hexyl-1-dodecyl group, 2-octyl- Preferred examples include 1-dodecyl group, 2-decyl-1-tetradecyl group, 2-dodecyl-1-hexadecyl group and the like.

The number of carbon atoms in the aralkyl group which may have a substituent is preferably 5 or more, and preferably 6 or more, from the viewpoint of improving the solubility of the peptide bound to the benzyl compound (X1) according to the present embodiment in an organic solvent. is more preferable, 7 or more is more preferable, 28 or less is preferable, 24 or less is more preferable, and 22 or less is even more preferable. Further, the aryl substituent is preferably a substituent containing a halogen atom. Specific examples of the alkyl group include 6-phenyl-1-hexyl group, 8-phenyl-1-octyl group, 10-phenyl-1-decyl group, 12-phenyl-1-dodecyl group and the like.

The number of carbon atoms in the aryl group which may have a substituent is preferably 6 or more, and preferably 7 or more, from the viewpoint of improving the solubility of the peptide bound to the benzyl compound (X1) according to the present embodiment in an organic solvent. is more preferable, 8 or more is more preferable, 16 or less is preferable, 14 or less is more preferable, and 12 or less is even more preferable. Moreover, as the substituent of the aryl group, an optionally substituted alkyl group is preferable, and an alkyl group containing a halogen atom is more preferable. In other words, R ² is preferably aryl having a substituent containing a halogen atom. Halogen atoms include fluorine, chlorine and bromine, with fluorine being particularly preferred.

Specific examples of the aryl group include a 3-trifluoromethylphenyl group, a 3,5-bistrifluoromethylphenyl group, a 4-fluoro-3-trifluoromethylphenyl group, a 4-chloro-2-fluorophenyl group, a 2- isopropylphenyl group, 2,6-isopropylphenyl group, 2-sec-butylphenyl group, 5-isopropyl-2-methylphenyl group and the like.

Each of the k ^R3 's is independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. For example, R ³ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group and the like, of which methyl group is particularly preferred. Specific examples of the alkoxy group include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, tert-butyloxy group and the like, among which methoxy group is particularly preferred. The halogen atom includes a fluorine atom, a chlorine atom and a bromine atom, of which the fluorine atom is particularly preferred.

<Specific examples of benzyl compounds>
(suitable substituents (-[Q ¹ -R ¹ -Q ² -R ² ]))
As the substituent (-[Q ¹ -R ¹ -Q ² -R ² ]) described above, substituents represented by the following formulas (XB1) to (XB3) are preferable in consideration of their usefulness. be able to. In the formulas (XB1) to (XB3), "*" represents the bonding position with the carbon atom constituting the benzene ring in the formula (X1).

(preferred benzyl compounds)
As the benzyl compound (X1) represented by the above formula (X1), compounds represented by the following formulas (X1A) to (X1D) can be mentioned as preferable ones in view of their usefulness.

The benzyl compound represented by the formula (X1A) is a benzyl compound represented by the formula (X1) in which three substituents represented by the above formula (XB1) are substituted at positions 3, 4 and 5. (3,4,5-tris(11-(3,5-bis(trifluoromethyl)phenoxy)undecyl)oxy)phenyl)methanol).

The benzyl compound represented by the formula (X1B) is a benzyl compound represented by the formula (X1) in which two substituents represented by the above formula (XB2) are substituted at positions 2 and 4. (2,4-bis((12-((2-octyldodecyl)oxy)dodecyl)oxy)phenyl)methanol).

The benzyl compound represented by the formula (X1C) is a benzyl compound represented by the formula (X1) in which three substituents represented by the above formula (XB2) are substituted at positions 3, 4 and 5. The resulting compound (3,4,5-tris((12-((2-octyldodecyl)oxy)phenyl)methanol)).

The benzyl compound represented by the formula (X1D) is a benzyl compound represented by the formula (X1) in which two substituents represented by the above formula (XB3) are substituted at positions 2 and 4. (2,4-bis((12-((2-decyltetradecyl)oxy)dodecyl)oxy)phenyl)methanol).

[Method for producing benzyl compound]
Next, the details of the method for producing the benzyl compound (X1) will be described. In the following description, [1] a method for producing a benzyl compound (X1) in which R ² in formula (X1) is a substituent other than an aryl group, and [2] a method for producing a benzyl compound (X1) in which R ² in formula (X1) is an aryl group Each of the methods for producing the benzyl compound (X1) will be explained separately.

[1] Method for producing benzyl compound (X1) in which R ² is a substituent other than an aryl group The method for producing the benzyl compound (X1) according to the present embodiment is not particularly limited. An example is described below. For example, a dialkyl bromide and an alkyl alcohol are dissolved in a suitable solvent and heated in the presence of a base to obtain an alkyl-etherified monobromide (hereinafter also referred to as "Step Xa1"). The resulting monobromide and a hydroxybenzcarbonyl compound (including a hydroxybenzaldehyde compound and a hydroxybenzester compound) are dissolved in an appropriate solvent and heated in the presence of a base such as potassium carbonate to form an alkyl-etherified benzaldehyde. A compound or a benzester compound is obtained (hereinafter also referred to as “Step Xa2”). Thereafter, the alkyl-etherified benzaldehyde compound or benzester compound is dissolved in an appropriate solvent, and the formyl group or ester group is reduced using a reducing agent such as a metal hydride (hereinafter also referred to as “step Xa3”). ), and a method of obtaining as a benzyl alcohol compound.

(Step Xa1)
In the above step Xa1, the base used for the reaction between the dialkyl bromide and the alkyl alcohol includes an organic base such as lithium diisopropylamide (LDA), lithium hexamethyldisilazide (LHMDS), sodium bis(trimethylsilyl)amide (NaHMDS). , sodium hydride (NaH), and lithium hydride (LiH). The amount of the base used is not particularly limited, but it is preferable to use 1.0 mol or more and 10 mol or less, more preferably 1.0 mol or more and 5 mol or less, relative to 1 mol of the alkyl alcohol. preferable.

Solvents include hydrocarbons such as hexane and heptane, diisopropyl ether, tetrahydrofuran (THF), cyclopentyl methyl ether (CPME), 4-methyltetrahydropyran (MTHP), ethers such as dioxane, dimethylformamide (DMF), dimethyl Examples include amides such as acetamide, sulfoxides such as dimethylsulfoxide (DMSO), lactams such as N-methylpyrrolidone, aromatic hydrocarbons such as toluene and xylene, and mixed solvents thereof. Among these, toluene is preferably used in terms of allowing the reaction to proceed smoothly.

The amount of solvent used is not particularly limited, but it is preferable to use 5 mL or more and 100 mL or less, more preferably 10 mL or more and 50 mL or less, per 1 g of alkyl alcohol. Moreover, when a mixed solvent is used, the total amount of the mixed solvent should satisfy the above range. Hereinafter, similar description may be omitted.

Although the reaction temperature is not particularly limited, it may be carried out in the range of 70°C to 150°C, for example. Also, the reaction time is not particularly limited, but may be, for example, 1 hour to 24 hours.

(Step Xa2)
In the above step Xa2, the base used for the reaction between the alkyl-etherified monobromide and the benzaldehyde compound or benzester compound includes triethylamine (TEA), diisopropylethylamine (DIPEA), 1,8-diazabicyclo [5.4. 0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), pyridine , imidazole, 4-(dimethylamino)pyridine (DMAP), LDA, sodium acetate (NaOAc), sodium methoxide (MeONa), potassium methoxide (MeOK), lithium hexamethyldisilazide (LHMDS), sodium bis(trimethylsilyl ) organic _bases such as amides (NaHMDS), sodium carbonate ( _Na2CO3 ), _sodium hydrogen _carbonate (NaHCO3) _, potassium carbonate ( _K2CO3 ), cesium carbonate ( _Cs2CO3 ), sodium hydride (NaH) and inorganic bases such as Among these, K ₂ CO ₃ is preferably used as the base in terms of allowing the reaction to proceed smoothly. The amount of the base used is not particularly limited, but it is preferable to use 1 mol or more and 10 mol or less, more preferably 2 mol or more and 8 mol or less, per 1 mol of the benzaldehyde compound or benzester compound. preferable.

As the solvent, the solvent described in step Xa1 may be used. As the solvent, DMF or a mixed solvent of DMF and CPME or MTHP is preferably used, and DMF is more preferably used, in order to allow the reaction to proceed smoothly. The amount of the solvent used is not particularly limited, but it is preferably 30 mL or more and 200 mL or less, more preferably 50 mL or more and 180 mL or less, per 1 g of the benzaldehyde compound or benzester compound.

Although the reaction temperature is not particularly limited, it may be carried out in the range of 50°C to 150°C, for example. Also, the reaction time is not particularly limited, but may be, for example, 1 hour to 24 hours.

(Step Xa3)
In step Xa3 above, the reducing agent used for reducing the formyl group of the alkyl-etherified benzaldehyde compound or the ester group of the benzester compound to obtain the benzyl alcohol compound includes sodium borohydride, lithium borohydride, lithium triethylborohydride, lithium aluminum hydride, aluminum hydride, sodium bis(2-methoxyethoxy)aluminum hydride, and diisobutylaluminum hydride. The reducing agent used for reducing the formyl group of the benzaldehyde compound is preferably sodium borohydride, and the reducing agent used for reducing the ester group of the benzester compound includes sodium borohydride, lithium borohydride, Lithium triethylborohydride, lithium aluminum hydride, aluminum hydride, sodium bis(2-methoxyethoxy)aluminum hydride, diisobutylaluminum hydride are preferred. When sodium borohydride is used as a reducing agent, for example, iodine, sulfuric acid, borane trifluoroetherate (BF ₃ Et ₂ O), etc. may be allowed to coexist in order to increase the reducing power of the reducing agent. is preferred.

Solvents include hydrocarbons such as hexane and heptane, alcohols such as methanol and ethanol, ethers such as diethyl ether, isopropyl ether, THF, CPME, MTHP and dioxane, aromatic hydrocarbons such as toluene and xylene, Alternatively, a mixed solvent thereof may be used. As the solvent used for reduction of the formyl group, a mixed solvent of alcohols and ethers is preferably used from the viewpoint of allowing the reaction to proceed smoothly. The amount of the solvent used is not particularly limited, but it is preferably 1 mL or more and 100 mL or less, more preferably 5 mL or more and 50 mL or less, per 1 g of the benzaldehyde compound. Moreover, when using the mixed solvent of alcohols and ethers, it is preferable to use 1 mL or more and 10 mL or less of ethers with respect to 1 mL of alcohols.

Solvents used for reduction of ester groups include ethers such as diethyl ether, isopropyl ether, THF, CPME, MTHP and dioxane, aromatic hydrocarbons such as toluene and xylene, and mixed solvents thereof. THF, CPME, and MTHP are preferably used as the solvent for reducing the methyl ester group from the viewpoint of smooth progress of the reaction. The amount of the solvent used is not particularly limited, but it is preferably 1 mL or more and 100 mL or less, more preferably 5 mL or more and 50 mL or less, per 1 g of the ester compound.

Although the reaction temperature is not particularly limited, it may be carried out in the range of -10°C to 90°C, for example. Also, the reaction time is not particularly limited, but may be, for example, 1 hour to 24 hours.

[2] Method for producing a benzyl compound (X1) in which R ² in formula (X1) is an aryl group The method for producing a benzyl compound in which R ² in formula (X1) has an aryl group is particularly limited. isn't it. An example is described below. For example, a bromoalkyl alcohol and a phenol compound having a substituent are heated in the presence of a base to obtain an aryl-etherified bromoalkyl alcohol compound (hereinafter also referred to as “Step Xb1”). After obtaining the aryl-etherified bromoalkyl alcohol, a bromoalkylaryl ether compound in which the hydroxyl group is substituted with a bromine atom is obtained (hereinafter also referred to as “step Xb2”).

The obtained bromoalkylaryl ether compound and the hydroxybenzaldehyde compound or hydroxybenzester compound are heated in the presence of a base such as potassium carbonate to obtain an alkyl-etherified benzaldehyde compound or benzester compound (hereinafter referred to as “Step Xb3 ”). After obtaining the alkyl-etherified benzaldehyde compound or benzester compound, the compound is dissolved in an appropriate solvent, and the formyl group or ester group is reduced using a reducing agent (hereinafter also referred to as “step Xb4”. ) and benzyl alcohol.

(Step Xb1)
In the above step Xb1, the base used for the reaction between the bromoalkyl alcohol and the substituted phenol compound includes TEA, DIPEA, DBU, DBN, DABCO, pyridine, imidazole, DMAP, LDA, NaOAc, MeONa, MeOK, and LHMDS. , NaHMDS, and inorganic bases such as Na ₂ CO ₃ , NaHCO ₃ , K ₂ CO ₃ , Cs ₂ CO ₃ , and NaH. Among these, K ₂ CO ₃ is preferably used as the base in terms of allowing the reaction to proceed smoothly. The amount of the base used is not particularly limited, but it is preferable to use 1 mol or more and 10 mol or less, more preferably 1 mol or more and 5 mol or less, per 1 mol of the phenol compound having a substituent. preferable.

As the solvent, the solvent described in step Xa1 may be used. DMF is preferably used as the solvent in terms of allowing the reaction to proceed smoothly. The amount of the solvent used is not particularly limited, but it is preferably 2 mL or more and 100 mL or less, more preferably 4 mL or more and 50 mL or less, per 1 g of the phenol compound having a substituent.

Although the reaction temperature is not particularly limited, it may be carried out in the range of 40°C to 150°C, for example. Also, the reaction time is not particularly limited, but may be, for example, 1 hour to 24 hours.

(Step Xb2)
In the above step Xb2, the reagent used in the reaction for converting the hydroxyl group of the aryl-etherified bromoalkyl alcohol into a bromine atom includes a reagent containing triphenylphosphine and carbon tetrabromide, a reagent containing hydrobromic acid, and the like. is mentioned. The amount of the reagent used is not particularly limited, but it is preferably 0.5 mol or more and 10 mol or less, and 1 mol or more and 5 mol or less, per 1 mol of the aryl-etherified bromoalkyl alcohol. It is more preferable to use

Examples of solvents include the solvents described in step Xa1, halogenated hydrocarbons such as dichloromethane and chloroform, and mixed solvents thereof. Halogenated hydrocarbons are preferably used as the solvent in terms of allowing the reaction to proceed smoothly. The amount of the solvent used is not particularly limited, but it is preferably 0.5 mL or more and 100 mL or less, more preferably 1 mL or more and 50 mL or less, per 1 g of the aryl-etherified bromoalkyl alcohol. .

Although the reaction temperature is not particularly limited, it may be carried out in the range of 20°C to 150°C, for example. Also, the reaction time is not particularly limited, but may be, for example, 1 hour to 24 hours.

(Step Xb3)
In step Xb3 above, as the base used for the reaction between the bromoalkylaryl ether and the benzaldehyde compound or benzester compound, the base explained in step Xb1 can be used. In step X3b, the same base as that used in step X1b may be used, or a different base may be used. However, it is preferable to use the same base as the base used in step X1b in terms of production efficiency and cost reduction. The amount of the base used is not particularly limited, but it is preferable to use 1 mol or more and 50 mol or less, more preferably 3 mol or more and 30 mol or less, per 1 mol of the benzaldehyde compound or benzester compound. preferable.

As the solvent, the solvent described in step Xa1 may be used. DMF is preferably used as the solvent in terms of allowing the reaction to proceed smoothly. The amount of the solvent used is not particularly limited, but it is preferably 30 mL or more and 200 mL or less, more preferably 50 mL or more and 180 mL or less, per 1 g of the benzester compound.

(Step Xb4)
As the reducing agent used to obtain the benzyl alcohol compound by reducing the formyl group of the alkyl-etherified benzaldehyde compound or the ester group of the benzester compound, the reducing agent used in the above step Xa3 can be used.

Solvents include hydrocarbons such as hexane and heptane, alcohols such as methanol and ethanol, ethers such as diethyl ether, isopropyl ether, THF, CPME, MTHP and dioxane, aromatic hydrocarbons such as toluene and xylene, Alternatively, a mixed solvent thereof may be used.

[Peptide synthesis]
A peptide synthesis method using the benzyl compound (X1) of the present invention as a protective group at the C-terminal of an amino acid is, for example, a production method comprising the following steps (X1) to (X5). In this peptide synthesis method, the C-terminal protected peptide obtained in each condensation step can be separated by liquid-liquid separation, which facilitates the purification step.

Step (X1) a step of dissolving the benzyl compound (X1) of the present invention in a soluble solvent (dissolving step);
Step (X2) a step of condensing the benzyl compound (X1) according to the present embodiment dissolved in the solvent obtained in the above step and a reaction substrate (condensation reaction step);
Step (X3) A base is added to the reaction solvent containing the condensate obtained above to scavenge the amino acid active ester, which is an unreacted substance, and deprotect the peptide N-terminal protecting group, and the protecting group a step of scavenging the derived by-products with a base (deprotection and scavenging reaction step);
Step (X4) An acidic aqueous solution is added to the reaction solution containing the condensate and the scavenged product obtained in the above step for washing, and the layers are separated to remove the scavenged product and unreacted substances (condensing agent, activator, base) with water. A step of removing into layers (layer splitting step), and
Step (X5) A step of removing the benzyl compound (X1) according to the present embodiment and the protective group of the peptide side chain from the C-terminal of the peptide and performing purification to obtain the target peptide (deprotection and purification step).

Each process will be explained below. In the following description, the benzyl compound (X1) (hereinafter also referred to as “tag X”) according to the present embodiment has N (N represents an amino group at the α-position of an amino acid)-9-fluorenylmethyloxycarbonyl The introduction of (N-Fmoc) protected amino acids and the condensation reaction of N-Fmoc protected amino acids to tag-protected peptides are described as examples. The N-Fmoc protected amino acids used may have side chain protecting groups. Although the Fmoc group is used as an example of the amino acid N-terminal protective group, the amino acid protective group is not limited to this. Examples include benzyloxycarbonyl group (Cbz group), tert-butoxycarbonyl group (Boc group), allyloxycarbonyl group (Alloc group) and the like.

[Step (X1) (dissolving step)]
This step is a step of dissolving tag X in a soluble solvent.
As a soluble solvent, a general organic solvent used for peptide synthesis can be used for the reaction. For example, ethers such as diethyl ether, THF, 2-methyltetrahydrofuran, 1,4-dioxane, methyl-t-butyl ether, CPME and MTHP, acetic esters such as ethyl acetate and isopropyl acetate, halogenation such as chloroform and dichloromethane Examples include hydrocarbons, aromatic hydrocarbons such as toluene and xylene, and hydrocarbons such as hexane, heptane and cyclohexane. From the viewpoint of good reactivity, liquid separation and industrial applicability, methyl-t-butyl ether, CPME, MTHP, isopropyl acetate, chloroform and toluene are preferred, and CPME, MTHP, isopropyl acetate and toluene are more preferred. CPME and MTHP are particularly preferred.

In addition, the soluble solvent is used to improve the solubility of the substrate in the reaction, to improve the solubility of unreacted substances and by-products in the aqueous layer during extraction, or to improve the liquid separation. , DMF, dimethylacetamide, DMSO, sulfolane, N-methylpyrrolidone, N,N'-dimethylpropylene urea (DMPU), acetonitrile, etc., in a suitable ratio.

[Step (X2) (condensation reaction step)]
In this step, an N-Fmoc protected amino acid is introduced into the tag X dissolved in the soluble solvent obtained in the above step (X1), an esterification reaction and an N-Fmoc protected amino acid are introduced into the tag X-protected peptide, This is the step of carrying out the amidation reaction.

The amount of the N-Fmoc-protected amino acid used is 1 to 4 mol, preferably 1 to 2 mol, particularly preferably 1.05 to 1.3 mol, relative to 1 mol of tag X.

In the reaction to introduce the N-Fmoc-protected amino acid into the tag X, an ester bond is formed by adding a condensing agent under the presence of dimethylaminopyridine (DMAP) catalyst in a solvent that does not affect the reaction.

In addition, in the condensation reaction of the N-Fmoc-protected amino acid to the tag X-protected peptide, an amide bond is formed by adding a condensing agent and an activating agent in a solvent that does not affect the reaction.

The condensing agent is not particularly limited as long as the reaction proceeds, and condensing agents commonly used in peptide synthesis can be used.

For example, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorphonium chloride (DMT-MM), O-(benzotriazol-1-yl)-1, 1,3,3-tetramethyluronium hexafluorophosphate (HBTU), O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HATU), O-(6-chlorobenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU(6-Cl)), O-(benzotriazol-1-yl)-1 , 1,3,3-tetramethyluronium tetrafluoroborate (TBTU), O-(6-chlorobenzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TCTU) , (1-cyano-2-ethoxy-2-oxoethylideneaminooxy)dimethylamino-morpholino-carbenium hexafluorophosphate (COMU), diisopropylcarbodiimide (DIPCI), dicyclohexylcarbodiimide (DCC), 1-ethyl-3 -(3-dimethylaminopropyl)carbodiimide (EDCI) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI·HCl), preferably DMT-MM, HBTU, HATU , COMU, EDCI or EDCI.HCl. The amount of the condensing agent used is usually 1 to 4 equivalents, preferably 1 to 2 equivalents, more preferably 1.05 to 1.5 equivalents, still more preferably 1.05 to 1.05 equivalents, relative to the tag X or the tag X-protected peptide. 1.3 equivalents.

In the condensation reaction step, an activator is preferably added in order to promote the reaction and suppress side reactions such as racemization. Here, the activating agent is a reagent that facilitates the formation of a peptide bond (amide bond) by leading an amino acid to a corresponding active ester, symmetrical acid anhydride, or the like in coexistence with a condensing agent. As the activator, activators commonly used in peptide synthesis can also be used in the present invention without limitation. (HOAt), ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt) 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (HOOBt), N -hydroxysuccinimide (HOSu), N-hydroxyphthalimide (HOPht), N-hydroxy-5-norbornene-2,3-dicarboximide (HONb), pentafluorophenol, ethyl cyano(hydroxyimino)acetate (Oxyma), etc. HOBt, HOAt, HOCt, HOOBt, HONb, HOSu and Oxyma are preferred. The amount of the activating agent to be used is generally 0.1-2 equivalents, preferably 0.2-1.5 equivalents, more preferably 0.3-1.0 equivalents, relative to the tag X-protected peptide.

Solvents commonly used in peptide synthesis can be used without limitation for the solvent used in the condensation reaction step, and examples thereof include, but are not limited to, the above-described soluble solvents or mixed solvents of soluble solvents and polar solvents. be done.

The amount of the solvent to be used is not particularly limited as long as the reaction proceeds, but it is an amount such that the concentration of the dissolved tag X-protected peptide or the like is usually 0.1 mM to 1 M, preferably 1 mM to 0.5 M. is the amount to be

As for the reaction temperature, the temperature generally used in peptide synthesis is also used in the present invention. The reaction time is usually 0.5 to 30 hours (condensation time for one residue).

[Step (X3) (deprotection and scavenging reaction step)]
In this step, after the amino acid condensation reaction step, the first base is added to the reaction solvent to capture (scavenge) unreacted amino acid active esters to form captured bodies and inactivate them. Furthermore, by adding the first base and the second base, the removal of the Fmoc group from the N-Fmoc-protected peptide proceeds, and the first base also acts as a scavenger for dibenzofulvene, which is a by-product derived from the Fmoc group. form and inactivate.

The amount of the first base used to scavenge unreacted amino acid active esters is not particularly limited, but is usually 1 to 5 equivalents, preferably 1 to 3 equivalents, relative to the theoretically remaining amino acid equivalents. .

The amount of the second base necessary for deprotecting the Fmoc group of the N-Fmoc protected peptide is preferably 1 to 12 equivalents, preferably 2 to 10 equivalents, relative to the Fmoc group present in the reaction system. More preferably, 3 equivalents to 8 equivalents are particularly preferred.

The amount of the first base used to scavenge the dibenzofulvene derived from the de-Fmoc group is preferably 5 equivalents to 50 equivalents, more preferably 8 equivalents to 40 equivalents, relative to the Fmoc groups present in the reaction system. 10 equivalents to 35 equivalents are particularly preferred.

[Step (X4) (layer splitting step)]
In this step, an acidic aqueous solution is added to the solution of the above step (X3) to neutralize it, and an acidic solution is added to remove the scavenger of the first base and the unreacted substances (condensing agent, activating agent, base). This is the step of removing to the water layer. The amino acid active ester and dibenzofulvene scavenged by the first base can be easily removed to the aqueous layer by acid washing.

The acid used for neutralization is not limited as long as it can neutralize the base in the reaction solution, but examples include aqueous solutions of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and the like. For example, when hydrochloric acid is used, 1M to 12M, preferably 3M to 12M, more preferably 5M to 12M hydrochloric acid is used. Neutralization here means that the reaction solution should have a neutral pH, and the pH may be 7.0 or less.

An acidic aqueous solution is further added to the reaction solution neutralized with the acid for washing, followed by liquid separation, removing the aqueous layer, and recovering the organic layer.

The acidic aqueous solution to be used is not particularly limited, but examples thereof include hydrochloric acid aqueous solution, dilute sulfuric acid aqueous solution, phosphoric acid aqueous solution, and acetic acid aqueous solution, preferably hydrochloric acid aqueous solution. The pH of the acidic aqueous solution is 1-5, preferably 1-4, more preferably 1-3.

The amount of the acidic aqueous solution used for washing is not particularly limited as long as it exhibits a washing effect. ~2 times the amount.

There are no particular restrictions on the number of washings, liquid separations, and discarding of the aqueous layer, and it may be performed once or multiple times. The number of times is appropriately selected depending on the type of compound in the reaction system, the amount of unnecessary substances, and the like.

The temperature for washing is not particularly limited, but is 10°C to 50°C, preferably 15°C to 45°C, more preferably 20°C to 40°C.

In this step, basically, the capturing body of the first base and unnecessary substances are removed with an acidic aqueous solution, but other cleaning steps may be added in addition to the cleaning with the acidic aqueous solution. For example, washing with a weak base and washing with a saline solution can be mentioned.

Examples of the weakly basic aqueous solution include an aqueous sodium hydrogen carbonate solution, an aqueous sodium carbonate solution, an aqueous potassium carbonate solution, etc., having a pH of 8 to 12.

As the salt solution, 5 wt% to saturated salt solution can be mentioned.

[Step (X5) (deprotection, purification step)]
This step is a step of removing the tag X and the protective group of the peptide side chain from the C-terminal of the peptide to obtain the target peptide.

The method for removing the tag X and the protective group of the peptide side chain from the peptide C-terminus is not particularly limited, and a known deprotection method may be used, preferably by acid treatment. For example, deprotection methods using trifluoroacetic acid (TFA) can be used.

Depending on the amino acid sequence, TFA may be used in combination with molecules such as water, thioanisole, 1,2-ethanedithiol, phenol, and triisopropylsilane in an appropriate composition.

The deprotected peptide can be isolated and purified according to purification methods commonly used in peptide synthesis. For example, the target peptide can be isolated and purified by extraction washing, crystallization, and chromatography.

[Embodiment 2]
[Benzyl compound]
The benzyl compound according to Embodiment 2 of the present invention has the following formula (Y1)

It is a benzyl compound (Y1) represented by. During the ceremony,
m Q's each represent an oxygen atom.
The total carbon number of the benzyl compound represented by formula (Y1) is preferably 30 or more and 80 or less, more preferably 40 or more and 60 or less.

( ^R1 )
In synthesizing a peptide by a liquid phase tagging method using a benzyl compound represented by the above formula (Y1), the inventors found that when peptide synthesis is performed using a particularly highly hydrophobic benzyl compound, As the peptide chain length increases, in the liquid separation operation in the separation/purification process after the completion of the reaction (see "liquid separation process" described later), the liquid separation becomes inadequate (after stirring the organic layer and the aqueous layer, Again, it took a long time to separate into an organic layer and an aqueous layer) (see Comparative Example Y3 and Table Y4, which will be described later).

It is speculated that this poor liquid separation is due to the formation of an emulsion (micelle structure) at the time of liquid separation between the organic layer and the aqueous layer containing a component in which a peptide is bound to a highly hydrophobic benzyl compound. Therefore, it is preferable that the hydrophobicity of the benzyl compound is not too high from the viewpoint of performing the liquid separation operation well. The hydrophobicity of benzylic compounds can be adjusted, for example, by the number of carbons contained in R ¹ and R ² .

In the present embodiment, for example, the number of carbon atoms of m R ¹ in the above formula (Y1) (hereinafter also referred to as “side chain carbon number”) is preferably in the range of 24 to 84, and the side chain More preferably, the number of carbon atoms in the chain is 30-72, and it is particularly preferable that the number of carbon atoms in the side chain is 36-48. In addition, each of the m R ¹ 's has a total of 1 or 2 branched chains. In addition, each of the m R ¹ is an alkyl group.

That is, R ¹ is an alkyl group having a total of 1 or 2 branched chains, preferably an alkyl group having a total of 1 or 2 branched chains and a total of 24 to 84 carbon atoms, It is more preferably an alkyl group having a total of 1 or 2 branched chains and a side chain carbon number of 30 to 72, having a total of 1 or 2 branched chains and a side chain carbon number of 36. ∼48 alkyl groups are particularly preferred.

Among the above, R ¹ is particularly preferably an alkyl group having one branched chain in total, and the position of the branched chain is 1 to 7 with respect to Q. is preferred, it is more preferably present at positions 1 to 4 with respect to Q, and more preferably at position 2 with respect to Q. Also, when R ¹ has two branches, the two branches are separated from each other by 0-6 carbons, preferably 0-3 carbons.

In addition, the above branched chain is an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aryl group. Among them, the branched chain is preferably an optionally substituted alkyl group having 2 to 12 carbon atoms, more preferably an optionally substituted alkyl group having 4 to 10 carbon atoms. This substituent is, for example, a halogen atom such as fluorine or chlorine.

Summarizing the above, m R ¹ are specifically each independently represented by the following formula (YA):

is preferably a group represented by In formula (YA),
* indicates the binding position. Similar descriptions may be omitted hereinafter.
_n1 is an integer of 0 or more and 6 or less, and _n2 is an integer of 0 or more and 6 or less. Preferably, _n1 represents an integer of 0 or more and 3 or less, and _n2 is an integer of 0 or more and 3 or less. When the _n1 is 1 or more, the repeating unit shown in the parentheses to which the _n1 is attached is an alkylene group, and when the _n2 is 1 or more, the parentheses to which the _n2 is attached The repeating units shown are alkylene groups.

R ^1a , R ^1b , R ^1c , R ^1d and R ^1e are each independently a hydrogen atom or an alkyl group. The above alkyl group may have a substituent, and the substituent is, for example, a halogen atom such as fluorine or chlorine. However, at least two or more of R ^1a , R ^1b , R ^1c and R ^1d are hydrogen atoms. Here, R ^1a , R ^1b , R ^1c and R ^1d may all be hydrogen atoms, but preferably all of R ^1a , R ^1b , R ^1c and R ^1d are hydrogen atoms. except. Specific examples of the group represented by the above formula (YA) have the same meanings as specific examples of the group represented by the above formula (XA), and thus description thereof is omitted.

In particular, R ¹ is preferably an organic group having one branched chain, and the branched chain is present at the 2-position relative to Q. That is, m R ¹ are each independently represented by the following formula (YA'):

is preferably a group represented by

Here, the difference between the number of carbon atoms in R ^1f and the number of carbon atoms in R ^1g is preferably 2. R ^1f is preferably a linear alkyl group having 4 to 12 carbon atoms which may have a substituent; It is more preferably a straight-chain alkyl group, and most preferably a straight-chain alkyl group having 6 carbon atoms, which may have a substituent. This substituent is, for example, a halogen atom such as fluorine or chlorine.

R ^1g is preferably a linear alkyl group having 6 to 14 carbon atoms, which may have a substituent, and a linear alkyl group having 6 to 12 carbon atoms, which may have a substituent It is more preferably a linear alkyl group, and most preferably a linear alkyl group having 8 carbon atoms, which may have a substituent. Examples of this substituent include halogen atoms such as fluorine, chlorine, bromine and iodine.

That is, the group represented by (YA′) above includes a 2-n-butyl-1-octyl group, a 2-hexyl-1-decyl group, a 2-octyl-1-dodecyl group, a 2-decyl-1- Preferred examples include a tetradecyl group and a 2-dodecyl-1-hexadecyl group.

( ^R2 )
Each of the k R ² is independently a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom. Specific examples of the k R ² are the same as the specific examples of the k R ³ in the first embodiment. The k R ² are more preferably hydrogen atoms.

X represents a hydroxyl group.
m represents an integer of 2 or 3;
k represents an integer of 0 or more (5-m) or less,
At least one of m [QR ¹ ] is preferably meta-substituted with respect to the substituent containing X.

The benzyl compound represented by formula (Y1) is particularly preferably used as a tag in long-chain peptide synthesis. For example, the benzyl compound represented by formula (Y1) is preferably used for synthesizing a peptide having 5 or more residues, and preferably used for synthesizing a peptide having 7 or more residues. More preferably, it is used for synthesizing ten or more peptides.

<Specific examples of benzyl compounds>
(suitable substituents (-[QR ¹ ])
As the substituent (-[QR ¹ ]) described above, substituents represented by the following formulas (YB1) to (YB3) can be mentioned as preferable ones in view of their usefulness. In the formulas (YB1) to (YB3), "*" represents the bonding position with the carbon atom constituting the benzene ring in the formula (Y1).

(preferred benzyl compounds)
As the benzyl compound (Y1) represented by the above formula (Y1), compounds represented by the following formulas (Y1A) to (Y1D) can be mentioned as preferable ones in view of their usefulness.

The benzyl compound represented by the formula (Y1A) is a benzyl compound represented by the formula (Y1) in which three substituents represented by the above formula (YB1) are located at the 3-position relative to the hydroxyl group (—OH). , (3,4,5-tris((2-butyloctyl)oxy)phenyl)methanol substituted at the 4- and 5-positions, respectively.

The benzyl compound represented by the formula (Y1B) is a benzyl compound represented by the formula (Y1) in which the three substituents represented by the above formula (YB2) are at the 3-position with respect to the hydroxyl group (—OH). , (3,4,5-tris((2-hexyldecyl)oxy)phenyl)methanol substituted at the 4- and 5-positions, respectively.

The benzyl compound represented by the formula (Y1C) is a benzyl compound represented by the formula (Y1) in which three substituents represented by the above formula (YB3) are located at the 3-position relative to the hydroxyl group (—OH). , (3,4,5-tris((2-decyltetradecyl)oxy)phenyl)methanol substituted at the 4- and 5-positions, respectively.

The benzyl compound represented by the formula (Y1D) is a benzyl compound represented by the formula (Y1) in which the three substituents represented by the above formula (YB3) are at the 3-position with respect to the hydroxyl group (--OH). and a compound (3,5-bis((2-decyltetradecyl)oxy)phenyl)methanol substituted at the 5-position, respectively.

[Method for producing benzyl compound]
Next, the details of the method for producing the benzyl compound (Y1) will be described.
The method for producing the benzyl compound (Y1) according to this embodiment is not particularly limited. An example is described below. For example, an alkyl halide and a hydroxybenzester compound are dissolved in an appropriate solvent and heated in the presence of a base such as potassium carbonate to obtain an alkyl-etherified benzester compound (hereinafter also referred to as "step Ya1"). .). Here, an alkyl halide is a compound in which a halogen atom is bonded to the tip of an alkyl group. Examples of the halogen atom include chlorine, bromine, and iodine. Considering reactivity, bromine or iodine is preferable, and bromine is more preferable considering cost. That is, the alkyl halide is preferably alkyl bromide or alkyl iodine, more preferably alkyl bromide. As the alkyl halide, a commercially available product may be used, or a hydroxyl compound corresponding to the starting material of the alkyl halide may be halogenated by a known method.

In this embodiment, an alkyl bromide and a hydroxybenzester compound are dissolved in an appropriate solvent and heated in the presence of a base such as potassium carbonate to obtain an alkyl-etherified benzester compound. As the alkyl bromide, a commercially available product may be used, or a hydroxyl derivative corresponding to the raw material of the alkyl bromide may be brominated by a known method. After that, the alkyl-etherified benzester compound is dissolved in an appropriate solvent, and the ester group is reduced using a reducing agent such as a metal hydride (hereinafter also referred to as “step Ya2”) to obtain a benzyl alcohol compound. A method of obtaining as

(Step Ya1)
In the above step Ya1, the base used for the reaction between the alkyl bromide and the hydroxybenzester compound includes triethylamine (TEA), diisopropylethylamine (DIPEA), 1,8-diazabicyclo[5.4.0]undec-7-ene. (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), pyridine, imidazole, 4-(dimethyl amino)pyridine (DMAP), lithium diisopropylamide (LDA), sodium acetate (NaOAc), sodium methoxide (MeONa), potassium methoxide (MeOK), lithium hexamethyldisilazide (LHMDS), sodium bis(trimethylsilyl)amide organic bases such as (NaHMDS), sodium carbonate ( _Na2CO3 ), sodium hydrogencarbonate _{(NaHCO3), potassium carbonate (K2CO3), cesium carbonate (Cs2CO3} ₎ _, _sodium _hydride ₍ NaH), etc. Inorganic bases can be mentioned. Among these, K ₂ CO ₃ is preferably used as the base in terms of allowing the reaction to proceed smoothly. The amount of the base used is not particularly limited, but it is preferably used in an amount of 1 to 10 mol, more preferably 2 to 8 mol, per 1 mol of the hydroxybenzester compound.

Solvents include hydrocarbons such as hexane and heptane, diisopropyl ether, tetrahydrofuran (THF), cyclopentyl methyl ether (CPME), 4-methyltetrahydropyran (MTHP), ethers such as dioxane, dimethylformamide (DMF), dimethyl Examples include amides such as acetamide, sulfoxides such as dimethylsulfoxide (DMSO), lactams such as N-methylpyrrolidone, aromatic hydrocarbons such as toluene and xylene, and mixed solvents thereof. Among them, it is preferable to use DMF or a mixed solvent of DMF and CPME in terms of allowing the reaction to proceed smoothly. The amount of the solvent used is not particularly limited, but it is preferably 10 mL or more and 200 mL or less, more preferably 15 mL or more and 150 mL or less, per 1 g of the hydroxybenzester compound.

(Step Ya2)
In the step Ya2, for example, a metal hydrogen compound may be used as the reducing agent used to reduce the ester group of the alkyl-etherified benzester compound to obtain the benzyl alcohol compound. As the metal hydride, a hydrogenated Group 13 alkali metal compound is preferred. Specifically, alkali metal borohydride compounds such as sodium borohydride, lithium borohydride, and lithium triethylborohydride, lithium aluminum hydride, aluminum hydride, and bis(2-methoxyethoxy)aluminum hydride Examples include aluminum hydride compounds such as sodium and diisobutylaluminum hydride. The amount of the reducing agent used is not particularly limited, but it is preferably used in an amount of 1 mol or more and 10 mol or less, preferably 2 mol or more and 5 mol or less, relative to 1 mol of the alkyl-etherified benzester compound. is more preferable.

When sodium borohydride is used as a reducing agent, for example, iodine, sulfuric acid, borane trifluoroetherate (BF ₃ Et ₂ O), etc. may be allowed to coexist in order to increase the reducing power of the reducing agent. is preferred.

Solvents used for reducing the ester group of the alkyl-etherified benzester compound include ethers such as diethyl ether, diisopropyl ether, THF, CPME, MTHP and dioxane, aromatic hydrocarbons such as toluene and xylene, or Mixed solvents of these are included. Among these, THF, CPME, and MTHP are particularly preferable as the solvent used for reducing the methyl ester group from the viewpoint of smooth progress of the reaction. The amount of the solvent used is not particularly limited, but it is preferably 1 mL or more and 100 mL or less, more preferably 5 mL or more and 50 mL or less, per 1 g of the ester compound.

[Peptide synthesis]
A method for synthesizing a peptide using the benzyl compound (Y1) of the present invention as a protective group (that is, tag) at the C-terminal of an amino acid is, for example, a production method including the following steps (Y1) to (Y6). This peptide synthesis method is capable of liquid-liquid separation of peptides with C-terminal protected amino acids (hereinafter also referred to as "C-terminal protected peptides") obtained in the condensation reaction step and the peptide elongation step. Therefore, the purification process is facilitated.

Step (Y1) a step of dissolving the benzyl compound (Y1) of the present invention in a soluble solvent (dissolving step),

Step (Y2) A condensing agent and an activating agent are added to the soluble solvent obtained in the above step, and the benzyl compound (Y1) dissolved in the soluble solvent and the second 1 amino acid (hereinafter also referred to as "N-terminal protected amino acid") to produce a first condensate (condensation reaction step);

Step (Y3) Soluble containing the first condensate obtained in the step (Y2) (condensation of the N-terminal protected amino acid and the benzyl compound (Y1) from which the —OH group has been removed) A first base is added to a solvent (reaction solvent) to scavenge the remaining amino acid active ester (resulting from the reaction of the C-terminal carboxylic acid of the surplus amino acid in step (Y2) with a condensing agent and then with an activating agent). (capturing), and further adding the first base and the second base to a soluble solvent (reaction solvent) to deprotect the N-terminal protective group from the N-terminal protected amino acid constituting the first condensate. , scavenging the by-product (dibenzofulvene) from the N-terminal protecting group with a first base (deprotection and scavenging reaction step);

Step (Y4) The second condensate obtained in the above step (Y3) (meaning a condensate in which the N-terminal protective group is removed from the first condensate), a scavenger (first base and amino active ester and is bound, and the first base and dibenzolfulvene are bound) and unreacted substances (by-products derived from condensing agents, activators, bases, water-soluble organic solvents) An acidic aqueous solution is added to the reaction solution (soluble solvent) to wash the solution, and the aqueous layer and the organic layer are separated to remove the capturing bodies and unreacted substances into the aqueous layer, and the organic layer separated from the aqueous layer. A step of obtaining a second condensate (i.e., C-terminal protected peptide) obtained by deprotecting the N-terminal protecting group from the first condensate in step (Y3) above (reaction solvent) (liquid separation step);
Step (Y5) A second amino acid having a protected N-terminus is added to the reaction solvent containing the second condensate obtained in the above step (Y4), and a second amino acid is produced in the same manner as in step (Y2). Following the condensation reaction of condensing the condensate and the N-terminally protected second amino acid to obtain a third condensate, the same methods as in steps (Y3) and (Y4) are performed, and the third A step of obtaining a fourth condensate in which the N-terminal protecting group is deprotected from the condensate of (peptide elongation step).

Step (Y5) includes repeating the following sub-steps (Y5-1) to (Y5-3):

Step (Y5-1) containing an amino acid whose N-terminus is not protected and an amino acid whose C-terminus is protected with a benzyl compound (Y1), and the total number (also referred to as "number of residues") is n (n is A natural number of 2 or more, preferably a natural number of 5 or more) is condensed with an n-th amino acid with a protected N-terminal to a 2n-th condensate containing amino acids, and the number of residues (n + 1) forming a (2n+1)th condensate comprising an amino acid of

Step (Y5-2) A step of scavenging the remaining amino acid active ester and then deprotecting the N-terminal protecting group from the (2n+1) condensate to scavenge the by-product derived from the N-terminal protecting group. ,as well as,

Step (Y5-3) Wash by adding an acidic aqueous solution to the soluble solvent, separate the phases, remove the captured body and unreacted substances into the aqueous layer, and transfer to the organic layer (reaction solvent) in the above step (Y5-2). A step of obtaining the obtained (2n+2)th condensate (referring to a deprotected condensate obtained by removing the N-terminal protecting group from the (2n+1)th condensate), and

Step (Y6) A step of removing the benzyl compound (Y1) and the protective group of the peptide side chain from the C-terminal of the peptide obtained in step (Y5) and purifying to obtain the target peptide (deprotection and purification step) .

Note that step (Y5) may be performed by repeating steps (Y2) to (Y4). In other words, step (Y2) includes sub-step (Y5-1), step (Y3) includes sub-step (Y5-2), and step (Y4) includes sub-step (Y5-3). and step (Y5) including substeps (Y5-1) to (Y5-3) may be performed by repeating such steps (Y2) to (Y4).

Each process will be explained below. In the following description, the case of using the benzyl compound (Y1) (hereinafter also referred to as “tag Y”) instead of the benzyl compound (X1) according to Embodiment 1 is described as an example.

[Step (Y1) (dissolving step)]
This step is a step of dissolving the benzyl compound (Y1) in a soluble solvent. Since step (Y1) can be performed in the same manner as step (X1) described above, detailed description thereof will be omitted.

[Step (Y2) (condensation reaction step)]
In this step, the tag Y and the N-Fmoc protected amino acid dissolved in the soluble solvent obtained in the above step (Y1) are introduced, the esterification reaction is performed, and the N-Fmoc protected amino acid is introduced into the tag Y-protected peptide to form an amide. This is the step of carrying out the conversion reaction. Since step (Y2) can be performed in the same manner as step (X2) described above, detailed description thereof will be omitted.

[Step (Y3) (deprotection and scavenging reaction step)]
In this step, after the amino acid condensation reaction step, the first base is added to the reaction solvent to capture (scavenge) unreacted amino acid active esters to form captured bodies and inactivate them. Furthermore, by adding the first base and the second base, the removal of the Fmoc group from the N-Fmoc-protected amino acid proceeds, and the first base also acts as a scavenger for dibenzofulvene, which is a by-product derived from the Fmoc group. form and inactivate. Since step (Y3) can be performed in the same manner as step (X3) described above, detailed description thereof will be omitted.

[Step (Y4) (liquid separation step)]
In this step, an acidic aqueous solution is added to the solution of the above step (Y3) for neutralization, and the scavenger of the first base and unreacted substances (condensing agent, activating agent, base, water-soluble organic solvent) are separated. It is a step of removing to the water layer by The amino acid active ester and dibenzofulvene scavenged by the first base can be removed to the aqueous layer by an acid wash.

The acid used for neutralization is not limited as long as it can neutralize the base in the reaction solution, but examples include aqueous solutions of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and the like. For example, when hydrochloric acid is used, 0.5M to 12M, preferably 1M to 12M, more preferably 1M to 6M hydrochloric acid is used. Neutralization here means that the reaction solution should have a neutral pH, and the pH may be 7.0 or less. In order to improve liquid separation, a ketone-based liquid separation promoting solvent such as acetone or methyl ethyl ketone may be further added. The inventors speculate that the reason for the decrease in liquid separation is that tag Y-peptide molecules associate with each other through hydrophobic interaction and hydrogen bonding to form a micelle structure, thereby reducing liquid separation. . By adding the above-mentioned liquid separation promoting solvent, the hydrophobic interaction between the side chains of the tag Y or the hydrogen bond between the peptide molecules is weakened, and the formation of the micelle structure is suppressed, thereby improving the liquid separation. It is estimated to be. It is also effective in improving the liquid separation property to perform the step of heating the solution in the step (Y3) instead of or together with the step of adding the liquid separation promoting solvent.

An acidic aqueous solution is further added to the reaction solution neutralized with the acid for washing, followed by liquid separation, removing the aqueous layer, and recovering the organic layer. Since the cleaning using the acidic aqueous solution can be performed in the same manner as the cleaning in step (X4) described above, detailed description thereof will be omitted.

The step (Y4) basically removes the capturing body of the first base and unnecessary substances with an acidic aqueous solution. may be added before or after washing with Examples include washing with a basic aqueous solution and washing with a saline solution.

As the basic aqueous solution, for example, a sodium bicarbonate aqueous solution, a sodium carbonate aqueous solution, or a potassium carbonate aqueous solution having a pH of 8 to 13 can be mentioned.

As the salt solution, 5 wt% to saturated salt solution can be mentioned. After washing with an acidic aqueous solution, washing with a basic aqueous solution is performed to make the pH of the solution neutral to weakly basic. Examples of the basic aqueous solution include the aqueous solutions described above.

[Step (Y5) (peptide elongation step)]
In this step, an N-terminally protected amino acid is added to the reaction solvent containing the tagged Y-protected peptide obtained in the above step, and the above steps (Y5-1) to (Y5-3) are repeated to obtain the peptide. This is the process of elongation. However, in the condensation reaction of this step, the DMAP used in the step (Y2) is not used, but the activating agent specified below is used.

The amount of the N-Fmoc-protected amino acid to be used is 1-4 mol, preferably 1-2 mol, particularly preferably 1.05-1.5 mol, per 1 mol of the benzyl compound (Y1).

In the peptide elongation step, the condensing agent used can be the same as the condensing agent described in step (Y2).

An activator is preferably added to promote the peptide condensation reaction and suppress side reactions such as racemization. Here, the activating agent is a reagent that facilitates the formation of a peptide bond (amide bond) by leading an amino acid to a corresponding active ester, symmetrical acid anhydride, or the like in coexistence with a condensing agent. As the activator, activators commonly used in peptide synthesis can also be used in the present invention without limitation. (HOAt), ethyl 1-hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt) 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (HOOBt), N -hydroxysuccinimide (HOSu), N-hydroxyphthalimide (HOPht), N-hydroxy-5-norbornene-2,3-dicarboximide (HONb), pentafluorophenol, ethyl cyano(hydroxyimino)acetate (Oxyma), etc. HOBt, HOAt, HOCt, HOOBt, HONb, HOSu and Oxyma are preferred. The amount of the activating agent used is generally 0.1-2 equivalents, preferably 0.2-1.5 equivalents, more preferably 0.3-1.0 equivalents, relative to the tag Y-protected peptide.

The solvent used in the peptide elongation step can be any solvent commonly used in peptide synthesis without limitation, and is not limited thereto. and a mixed solvent of

The amount of the solvent to be used is not particularly limited as long as the reaction proceeds, but it is an amount such that the concentration of the dissolved tag Y-protected peptide or the like is usually 0.1 mM to 1 M, preferably 1 mM to 0.5 M. is the amount to be

[Step (Y6) (deprotection, purification step)]
This step is a step of removing the benzyl compound (Y1) and protecting groups of peptide side chains from the C-terminus of the peptide to obtain the desired peptide. Since step (Y6) can be performed in the same manner as step (X5) described above, detailed description thereof will be omitted.

[Embodiment 3]
A third embodiment according to the present invention will be described below. It should be noted that the embodiments described below are shown as preferred specific examples for carrying out the present invention, and there are portions that specifically illustrate various technically preferable technical matters. The technical scope of the present invention is not limited to this specific embodiment.

In the following, for convenience of explanation, <1> a removal method of removing the protecting group from an amino group-containing compound protected with a protecting group having a fluorene skeleton at the N-terminus, and <2> a step of removing the protecting group. Details will be described in the order of <3> the removing agent for the protecting group.

<1> Method for removing protective group In the method for removing a protective group according to the present embodiment, an amino group-containing compound whose N-terminus is protected by a protective group having a fluorene skeleton is brought into contact with a scavenger in an organic solvent. obtaining a scavenger in which a by-product having a fulvene skeleton derived from the protecting group and the scavenger are bound; and separating the obtained scavenger from the organic solvent.

(Amino group-containing compound)
An amino group-containing compound means a compound having a primary amino group or a secondary amino group. Amino group-containing compounds include, for example, single amino acids, peptides formed by peptide bonds of a plurality of amino acids, amino acids, and the like.

(Protective group having a fluorene skeleton)
A protective group having a fluorene skeleton is a group that binds to the nitrogen atom in the N-terminal amino group of an amino group-containing compound to protect the N-terminal of the amino group-containing compound. This protecting group is a monovalent protecting group containing a fluorene structure represented by the following formula (Z2).

In formula (Z2), R ⁴ is an optionally substituted alkyloxycarbonyl group having 1 to 6 carbon atoms. R ^5a to R ^5d and R ^6a to R ^6d are each independently a hydrogen atom, an optionally substituted C 1-6 alkyl group, an optionally substituted C 1 It is an alkoxy group of up to 6, a sulfone group which may have a substituent, or a sulfonyl group which may have a substituent. Examples of substituents include halogen atoms and alkyl groups having 1 to 3 carbon atoms. "*" represents the bonding position with the N-terminal amino group of the amino group-containing compound.

R ⁴ is preferably an alkyloxycarbonyl group having 1 to 3 carbon atoms, and more preferably a methyloxycarbonyl group. R ^5a to R ^5d and R ^6a to R ^6d are each preferably hydrogen atoms.

That is, as a protective group having a fluorene skeleton represented by the above formula (Z2), a 9-fluorenylmethyloxycarbonyl group (Fmoc group) can be mentioned as a suitable example in consideration of its usefulness. .

An amino group-containing compound whose N-terminus is protected by a protecting group having a fluorene skeleton is a protecting group in which at least one of the primary amino group or secondary amino group possessed by the amino group-containing compound is the above-described protecting group having a fluorene skeleton. means a compound protected by

(capturing agent)
The scavenging agent is a reactive agent that binds to the protective group deprotected from the amino group-containing compound to capture the protective group to form a scavenging compound (see formula (Z3)). In addition to the function of capturing the deprotected protecting group, the scavenger also has the function of deprotecting the protecting group from the amino group-containing compound protected with the protecting group. The scavenger is a compound represented by the following formula (Z1). That is, the scavenger is at least one compound selected from the group consisting of a cyclic amine containing one nitrogen atom (see formula (Z1A)) and a hydrochloride containing the cyclic amine (see formula (Z1B)). .

In formula (Z1), N is a nitrogen atom. H is a hydrogen atom.

X is a divalent group represented by -CH ₂ -, -O-, -S- or -(SO ₂ )-. X is preferably -O- or -(SO ₂ )-. Including an oxygen atom in X lowers the basicity, thereby suppressing side reactions. X is optimally -O-.

n ₁ R ^1a , n ₁ R ^1b , n ₂ R ^2a , n ₂ R ^2b , n ₃ R ^3a , and n ₃ R ^3b are each independently H , —OH, —OR (R is an alkyl group), —SH, —SR (R is as defined for —OR above.), —(SO ₂ )H, or —(SO ₂ ) It is a monovalent group represented by R (R is the same as defined above for —OR). Also, R ^2a or R ^2b and R ^3a or R ^3b may be bonded to each other to form a ring together with the carbon atoms to which they are bonded.

Of n ₁ R ^1a , n ₁ R ^1b , n ₂ R ^2a and n ₂ R ^2b , the one bonded to the carbon atom adjacent to the nitrogen atom is preferably a hydrogen atom. . This is because the stability of the scavenger increases. In addition, one of n ₁ pair of R ^1a and R ^1b , n ₂ pair of R ^2a and R ^2b and n ₃ pair of R ^3a and R ^3b is preferably a hydrogen atom. Optimally, n ₁ R ^1a , n ₁ R ^1b , n ₂ R ^2a , n ₂ R ^2b , n ₃ R ^3a , and n ₃ R ^3b are each hydrogen is an atom.

n ₁ , n ₂ and n ₃ are each independently 1 or 2; The sum of n ₁ , n ₂ and n ₃ is preferably 3 or 4. That is, the scavenger represented by formula (Z1) is preferably represented by formula (Z1a) or formula (Z1b) below. The trapping agent represented by formula (Z1a) is a compound in which the sum of n ₁ , n ₂ and n ₃ is 3 in formula (Z1). The trapping agent represented by formula (Z1b) is a compound in which the sum of n ₁ , n ₂ and n ₃ is 4 in formula (Z1). m is an integer of 0 or 1;

In formulas (Z1a) and (Z1b) above, N, H, X, R ^1a , R ^1b , R ^2a , R ^2b , R ^3a , R ^3b , n ₁ , n ₂ , n ₃ and m are represented by formula (Z1 ) is synonymous with

When m is 0, the scavenger is a cyclic amine containing one nitrogen atom represented by the following formula (Z1A). When m is 1, the scavenger is hydrochloride represented by the following formula (Z1B). Note that m is preferably 0.

In formulas (Z1A) and (Z1B) above, N, H, X, R ^1a , R ^1b , R ^2a , R ^2b , R ^3a , R ^3b , n ₁ , n ₂ , and n ₃ are represented by formula (Z1) is synonymous with

That is, the scavenger is an amine that is cyclic and contains at least one element selected from the group consisting of oxygen element and sulfur element. Preferably, the amine is water soluble. Also, the scavenger is preferably a primary or secondary amine.

(suitable scavenger)
The scavenger represented by formula (Z1) above is preferably a cyclic amine having one amino group. The scavenger is, for example, at least one selected from the group consisting of morpholine, piperidine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide, preferably morpholine, 3-hydroxypiperidine , 4-hydroxypiperidine, thiomorpholine, and at least one selected from the group consisting of thiomorpholine dioxide, more preferably selected from the group consisting of morpholine, 3-hydroxypiperidine, and 4-hydroxypiperidine At least one, more preferably morpholine.

The amount of the scavenger to be added is 5 to 100 equivalents, preferably 5 to 50 equivalents, more preferably 10 to 30 equivalents, relative to the amount of protective groups present in the reaction system. If the amount of the scavenger to be added is less than this range, the by-product having a fulvene skeleton generated by the deprotection reaction of the protective group having a fluorene skeleton will be insufficiently captured, making it difficult to remove impurities by acidic liquid separation washing. If the amount of the scavenger added is more than this range, the scavenger may remain in the organic layer during acidic liquid-separating washing, which may cause side reactions.

(organic solvent)
The contact between the amino group-containing compound and the scavenger represented by formula (Z1) is carried out in an organic solvent. As for this organic solvent, it is preferable to use the same solvent as the reaction solvent used for the elongation (synthesis) reaction of the peptide in the liquid phase tagging method described below. This is because when the peptide elongation reaction is repeated sequentially, the removal of the protective group and the elongation of the peptide do not adversely affect each other, and the operation is facilitated. As the organic solvent, the same soluble solvent as described above for step (X1) can be used, and therefore detailed description thereof will be omitted.

(Method of contact)
The method of contacting each component is not particularly limited. For example, the ingredients may be mixed in a reaction vessel equipped with a stirring mechanism. By mixing each component, the amino group-containing compound and the scavenger can be brought into contact with each other. The procedure for mixing each component is not particularly limited. For example, after synthesizing an amino group-containing compound in an organic solvent, a scavenger may be mixed with the organic solvent containing the amino group-containing compound (hereinafter also referred to as "reaction solution").

[Deprotecting agent]
A deprotecting agent may be further mixed in order to accelerate the deprotection reaction of the protecting group. By mixing the deprotecting agent, the amino group-containing compound and the deprotecting agent can be contacted. Deprotecting agents include 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1.5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,4- At least one base selected from the group consisting of organic bases such as diazabicyclo[2.2.2]octane (DABCO) triethylamine and tributylamine, and inorganic bases such as potassium tert-butoxide and sodium tert-butoxide more preferably 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1.5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), more preferably 1,8-diazabicyclo[5.4.0]-7-undecene (DBU).

The amount of the deprotecting agent added in this step is preferably 1 to 12 equivalents, more preferably 2 to 10 equivalents, particularly preferably 3 to 8 equivalents, relative to the protective groups present in the reaction system.

The procedure for adding the deprotecting agent is not particularly limited. For example, the scavenger may be mixed with the reaction solution, or the deprotecting agent may be mixed with the reaction solution before the scavenger is mixed with the reaction solution.

(trapping body)
By contacting the amino group-containing compound with the scavenger represented by the above formula (Z1), a scavenger represented by the following formula (Z3) is obtained. This scavenger is a combination of a by-product having a fulvene skeleton represented by the following formula (Z2') and a scavenger represented by the above formula (Z1). A by-product represented by the following formula (Z2') is produced by deprotection of the protective group represented by the formula (Z2).

In the above formulas (Z2′) and (Z3), N, H, X, R ^1a , R ^1b , R 2a , R ^2b , R ^3a , R ^3b , R ^5a , R ^5b , R ^5c , ^{R 5d} ^, R ^6a , R ^6b , R ^6c , R ^6d , n ₁ , n ₂ , and n ₃ have the same meanings as in Formula (Z1) and Formula (Z2).

(Step of separating capture bodies)
Next, the step of separating the captured bodies obtained, that is, the step of removing them from the reaction solution will be described. The method shown below is an example of a method for separating captured bodies, and is not limited to the method shown below.

For example, an acidic aqueous solution is added to the above reaction solution to neutralize it, and the capturing body is guided to the aqueous layer by liquid separation. The scavengers can be guided into the aqueous layer and separated from the reaction solution by acid washing.

The acid used for neutralization is not limited as long as it can neutralize the base in the reaction solution, but examples include aqueous solutions of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and the like. For example, when hydrochloric acid is used, 0.5 M (“M” indicates mol/L. Hereinafter, the same description will be omitted.) to 12 M, preferably 1 M to 12 M, more preferably 1 M to 6 M hydrochloric acid Use Neutralization here means that the reaction solution should have a neutral pH, and the pH may be 7.0 or less. In order to improve liquid separation, a ketone-based liquid separation promoting solvent such as acetone or methyl ethyl ketone may be further added. The inventors speculate that tag-peptide molecules associate with each other through hydrophobic interaction and hydrogen bonding to form a micelle structure, which causes the liquid separation to decrease. By adding the above-mentioned liquid separation promoting solvent, the hydrophobic interaction between the side chains of the tag or the hydrogen bond between the peptide molecules is weakened, and the formation of the micelle structure is suppressed, so that the liquid separation is improved. Presumed. It is also effective in improving the liquid separation property to perform a step of heating the reaction solution instead of or together with the step of adding the liquid separation promoting solvent.

Further, an acidic aqueous solution is added to the reaction solution neutralized with the above acid for washing, then the solution is separated, the aqueous layer is separated, and the organic layer is recovered.

There are no particular restrictions on the number of washings, liquid separations, and discarding of the aqueous layer, and it may be performed once or multiple times. The number of times is appropriately selected depending on the type of compound in the reaction system, the amount of trapping material, and the like.

In this step, the captured material is basically removed with an acidic aqueous solution. However, if there is a captured material that is difficult to remove by washing with the acidic aqueous solution, other washing processes may be added before and after washing with the acidic aqueous solution. Examples include washing with a basic aqueous solution and washing with a saline solution.

Examples of salt water include 5 wt % to saturated salt water.
After washing with an acidic aqueous solution, washing with a basic aqueous solution is performed to make the pH of the solution neutral to weakly basic. Examples of the basic aqueous solution include the aqueous solutions described above.
[Method for removing Fmoc group]
Next, a preferred method for removing the protective group will be described in detail, taking as an example the case where the protective group is an Fmoc group. The method for removing the Fmoc group according to the present embodiment involves mixing a cyclic amine as a scavenger, an amino group-containing compound protected with an Fmoc group as a protecting group, and an optional deprotecting agent to deprotect the Fmoc group. a step of obtaining a scavenger in which the resulting dibenzofulvene (DBF) and a cyclic amine bind (hereinafter also referred to as "DBF-capturer") and an amino group-containing compound in which the Fmoc group is deprotected, and the resulting reaction mixture and washing with an acidic aqueous solution to remove the DBF-trapper to obtain an amino group-containing compound. A DBF-trapper is an example of a "trapper" of the present invention.

An amino group-containing compound protected by an Fmoc group means a compound in which at least one of the primary amino group or secondary amino group of the amino group-containing compound is protected by an Fmoc group.

Cyclic amines herein are cyclic amines having one amino group, such as morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide, as described above. morpholine, 3-hydroxypiperidine and 4-hydroxypiperidine are preferred, and morpholine is more preferred.

The amount of the cyclic amine added in the Fmoc group removal step is 5 to 100 equivalents, preferably 5 to 50 equivalents, more preferably 10 to 30 equivalents, relative to the amount of Fmoc groups present in the reaction system. be. If the amount of the cyclic amine added is less than this range, the capture of DBF produced by the Fmoc group deprotection reaction becomes insufficient, making it difficult to remove impurities by acidic liquid separation washing.

A deprotecting agent is a reactive agent that removes the Fmoc group from an amino group-containing compound protected with an Fmoc group. Deprotecting agents in the Fmoc group removal step include, as described above, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1.5-diazabicyclo[4.3.0] organic bases such as -5-nonene (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), triethylamine, and tributylamine; and inorganic bases such as potassium tert-butoxide and sodium tert-butoxide. More preferably, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1.5-diazabicyclo[4.3.0]-5-nonene (DBN), 1 , 4-diazabicyclo[2.2.2]octane (DABCO), more preferably 1,8-diazabicyclo[5.4.0]-7-undecene (DBU).

The amount of the deprotecting agent necessary for deprotecting the Fmoc group is preferably 1 to 12 equivalents, more preferably 2 to 10 equivalents, 3 to 8 equivalents, relative to the Fmoc group present in the reaction system. Equivalents are particularly preferred. Note that the deprotecting agent is not an essential reactant and does not necessarily have to be added. However, it is preferable to use a deprotecting agent because the reaction rate of the deprotection reaction of the Fmoc group can be increased by using the deprotecting agent together with the scavenger.

By concentrating the solution obtained by the Fmoc group deprotection reaction of the present invention, an amino group-containing compound in which the Fmoc group has been deprotected can be isolated. Furthermore, the obtained solution of the amino group-containing compound can be used as it is as a raw material for the peptide production method by the liquid phase synthesis method described below.

<2> Method for Producing Peptide Including Step of Removing Protecting Group [Method for Producing Peptide by Liquid Phase Synthesis]
When the amino group-containing compound protected with a protecting group is a C-protected peptide or the like in which the C-terminus is bound to a soluble carrier, the method for removing the protecting group of the present invention is the method for producing a peptide by liquid phase synthesis. It can be used preferably.

A method for synthesizing a peptide, including the method for removing the protective group described above, will be described below.
This peptide synthesis method comprises an amino group-containing compound such as an amino acid, peptide, or amino acid amide whose C-terminal is protected with a specific carrier for liquid-phase peptide synthesis (hereinafter also referred to as "C-terminal carrier-protected peptide"), A step of condensing an amino group-containing compound (hereinafter also referred to as an “N-terminal protected peptide”) whose N-terminus is protected with the above-described protecting group (see formula (Z2)) (step Z1), and remaining after the condensation reaction A step of quenching the active ester (step Z2), a step of deprotecting the protective group from the condensed peptide (hereinafter also referred to as “N-terminal protected-C-terminal carrier-protected peptide”) (step Z3), and adding an acidic aqueous solution to the reaction solution. (Step Z4), and deprotecting the C-terminal carrier and side chain protecting groups (Step Z5). In the peptide synthesis method described above, a peptide production method is characterized in that a by-product having a fulvene skeleton generated after deprotection of the N-terminal protective group is captured using a cyclic amine.

For convenience of explanation, the liquid-phase peptide synthesis method including the method for removing the Fmoc group will be described in detail below, taking Fmoc as an example of the protective group. The protective group is not limited to the Fmoc group, and the method shown below can also be applied to an amino group-containing compound protected with a protective group represented by formula (Z2) above.

(Step Z1: condensation step)
In an organic solvent, in the presence of a condensing agent, a C-terminal carrier-protected peptide protected with a carrier for liquid-phase peptide synthesis", and an amino acid or peptide whose N-terminus is protected with an Fmoc group (hereinafter referred to as "N-Fmoc-protected amino acid or Also referred to as "peptide") is condensed to obtain a peptide with extended amino acid residues (hereinafter also referred to as "N-Fmoc-protected-C-terminal carrier-protected peptide").

[Carrier for Liquid Phase Peptide Synthesis]
<<1>> Carriers for liquid-phase peptide synthesis used in step Z1 include, for example, the following compounds.

That is, one example of the carrier for liquid-phase peptide synthesis is the benzyl compound (X1) represented by the above formula (X1). Since the structure of the benzyl compound (X1) is the same as that of Embodiment 1 described above, detailed description thereof will be omitted.

As the benzyl compound (X1) represented by the above formula (X1), compounds represented by the following formulas (X1A) to (X1D) can be mentioned as preferable ones in consideration of their usefulness.

<<2>> Another example of the carrier for liquid-phase peptide synthesis is a benzyl compound (Y1) represented by the following formula (Y1). Since the structure of the benzyl compound (Y1) is the same as that of Embodiment 2 described above, detailed description thereof will be omitted.

As the benzyl compound (Y1) represented by the above formula (Y1), compounds represented by the following formulas (Y1A) to (Y1D) can be mentioned as preferable ones in view of their usefulness.

The carrier for liquid-phase peptide synthesis used in step Z1 is not limited to the benzyl compound (X1) represented by formula (X1) and the benzyl compound (Y1) represented by formula (Y1). It may be a compound.

<<3>> Another preferred example of the carrier for liquid-phase peptide synthesis is a compound represented by the following formula (Z6).

<<4>> Other examples of carriers for liquid-phase peptide synthesis include compounds represented by the following formula (Z7).

<<5>> Other examples of carriers for liquid-phase peptide synthesis include compounds represented by the following formulas (Z8-1), (Z8-2), and (Z8-3).

<<6>> Other examples of carriers for liquid-phase peptide synthesis include compounds represented by the following formula (Z9).

<<7>> Other examples of carriers for liquid-phase peptide synthesis include compounds represented by the following formula (Z10).

〔amino acid〕
N-Fmoc-protected C-terminal carrier-protected peptides, etc., C-terminal carrier-protected peptides, and amino acids forming the basic structure of N-Fmoc-protected amino acids may be either natural amino acids or non-natural amino acids. Also, this amino acid may be either L- or D-form. Natural amino acids include Arg, Lys, Asp, Asn, Glu, Gln, His, Pro, Tyr, Trp, Ser, Thr, Gly, Ala, Met, Cys, Phe, Leu, Val, Ile, β-Ala, and the like. mentioned. Unnatural amino acids include Tle (tert-leucine) and the like.

Amino acids may have side chain functional groups. The side chain amino group is desirably protected by a protective group other than the Fmoc group, such as a Boc group, a Cbz group, an Alloc group, an Ac group, or the like.

Examples of protective groups for side chain carboxy groups include alkyl groups such as methyl groups, ethyl groups and tBu groups, and benzylic substituents such as benzyl groups and p-methoxybenzyl groups. A trityl (Tr) group etc. are mentioned as a protection group of an amide group. A benzyl group, a tBu group, etc. are mentioned as a side-chain hydroxy-protecting group. Examples of side-chain imidazole-protecting groups include Boc, Trt, and Bom (benzyloxymethyl) groups. Examples of side-chain guanidyl-protecting groups include a nitro group and a Pbf group. Examples of thiol-protecting groups include Trt group, Acm group, Dpm group, Ddm group, tBu group, S-tBu group, Mmt group and Npys group.

The amount of the N-Fmoc-protected amino acid used is 1 to 4 mol, preferably 1 to 2 mol, particularly preferably 1.05 to 1.3 mol, per 1 mol of the carrier for liquid phase peptide synthesis. .

[Condensation agent]
The condensing agent is not particularly limited as long as the reaction proceeds, and condensing agents commonly used in peptide synthesis can be used. As the condensing agent, the one described in the context of step (X2) (condensation reaction step) can be used, and therefore detailed description thereof is omitted.

An activator is preferably added to promote the peptide condensation reaction and suppress side reactions such as racemization. As the activating agent, the one described in the context of step (X2) (condensation reaction step) can be used, and therefore detailed description thereof is omitted.

[Reaction solvent]
As the reaction solvent used in the condensation reaction step (hereinafter also referred to simply as "solvent"), any solvent commonly used in peptide synthesis can be used without limitation. A mixed solvent of a solvent and a polar solvent can be mentioned. As the soluble solvent, the one described in the context of step (X1) (dissolving step) can be used, and therefore detailed description thereof will be omitted.

In addition, the soluble solvent is used to improve the solubility of the substrate in the reaction, to improve the solubility of unreacted substances and by-products in the aqueous layer during extraction, or to improve the liquid separation. , DMF, dimethylacetamide, DMSO, sulfolane, N-methylpyrrolidone, N,N'-dimethylpropylene urea (DMPU), acetonitrile, etc., in a suitable ratio. The mixing ratio is not particularly limited as long as the reaction proceeds, but the amount is such that the ratio of the soluble solvent and the polar solvent is 50:50 to 95:5, preferably 70:30 to 90:10. quantity.

The amount of the solvent to be used is not particularly limited as long as the reaction proceeds, but it is an amount such that the concentration of the dissolved tag is usually 0.1 mM to 1 M, preferably 1 mM to 0.5 M. be.

As for the reaction temperature, the temperature generally used in peptide synthesis is also used in the present invention. The reaction time is usually 0.5 to 30 hours (condensation time for one residue).
This reaction solvent is an example of the "organic solvent" in the present invention, and can be used in steps Z3 and Z4 described below.

(Step Z2: Active ester quenching step)
An amine is added to the reaction solvent containing the N-Fmoc-protected C-terminal carrier-protected peptide obtained in step Z1 above, and the remaining amino acid active ester (condensing agent, Then, scavenging is performed. The amine used in this step may be referred to as the first scavenger.

Amines as first scavengers that can be used in step Z2 are preferably primary or secondary water-soluble amines, for example morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, thiomorpholine di oxide, 1-methylpiperazine, 4-aminopiperidine, N,N-dimethylethylenediamine, ethylenediamine, preferably morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, thiomorpholine dioxide. , more preferably morpholine, 3-hydroxypiperidine and 4-hydroxypiperidine, and still more preferably morpholine.

The amount of amine added as a scavenger in step Z2 is not particularly limited, but is usually 1 to 5 equivalents, preferably 1 to 3 equivalents, relative to the theoretically remaining amino acid equivalents.

(Step Z3: Fmoc group deprotection and capture step)
A deprotecting agent is added to the reaction solution obtained in step Z2 to deprotect the N-terminal Fmoc group from the N-Fmoc-protected-C-terminal carrier-protected peptide. Furthermore, this step includes a step of catching Fmoc group-derived by-products (DBF) with a second scavenger. In addition, the reaction solution is an example of the "organic solvent" of the present invention. Also, the second scavenger is an example of the "trapping agent" of the present invention. The step of scavenging DBF with a second scavenger is an example of the "step of obtaining a scavenger" of the present invention.

The amount of the deprotecting agent added in this step is preferably 1 to 12 equivalents, more preferably 2 to 10 equivalents, particularly preferably 3 to 8 equivalents, relative to the Fmoc groups present in the reaction system.

The deprotecting agent is not particularly limited, but 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1.5-diazabicyclo[4.3.0]-5-nonene, 1,4 -diazabicyclo[2.2.2]octane, potassium tert-butoxide, sodium tert-butoxide, triethylamine and tributylamine, preferably DBU.

The amount of the second scavenger used to scavenge DBF derived from the de-Fmoc group is preferably 5 equivalents to 50 equivalents, more preferably 8 equivalents to 40 equivalents, more preferably 10 equivalents, relative to the Fmoc groups present in the reaction system. Equivalents to 35 equivalents are particularly preferred.

A second scavenger that can be used in step Z3 is an amine as a DBF scavenger. The amine, as described above, is cyclic and contains at least one element selected from the group consisting of an oxygen element or a sulfur element, and is preferably a primary or secondary water-soluble amine, Examples include morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine and thiomorpholine dioxide, preferably morpholine, 3-hydroxypiperidine and 4-hydroxypiperidine, more preferably morpholine is.

The second scavenger in this step may be the same as or different from the first scavenger added in step Z2 (active ester quenching step). However, in order to simplify the operation and reduce the use of scavengers, the second scavenger used in step Z3 is preferably the same as the first scavenger added in step Z2. In this case, in step Z2, among the above-mentioned amines, cyclic amines such as morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine and thiomorpholine dioxide are preferably used.

(Step Z4: Acidic aqueous solution washing step)
Step Z4 is an example of the "separating step" of the present invention. That is, in this step, an acidic aqueous solution is added to the reaction solution of the above step Z3 to neutralize it, and the first scavenger and amino acid active ester are combined (hereinafter also referred to as "amino acid active ester-capturing body"). , and unreacted substances (here, the unreacted substances are condensing agents, activating agents, deprotecting agents, polar solvents among the reaction solvents described above, etc.) are removed into the aqueous layer by liquid separation. The amino acid active ester scavenged by the first scavenger (i.e. amino acid active ester-capture) and the DBF scavenged by the second scavenger (i.e. DBF-capture) are introduced into the aqueous layer by acidic washing. As such, they can be separated from the reaction solution.

The acid used for neutralization can be the one described in the context of step (Y4) (liquid separation step), so a detailed description thereof will be omitted.

Further, an acidic aqueous solution is added to the reaction solution neutralized with the above acid for washing, followed by liquid separation, removing the aqueous layer, and recovering the organic layer.

There are no particular restrictions on the number of washings, liquid separations, and discarding of the aqueous layer, and it may be performed once or multiple times. The number of times is appropriately selected depending on the type of compound in the reaction system, the amount of unreacted substances, and the like.

In this step, the amino acid active ester-captured body, the DBF-captured body, and unreacted substances are basically removed with an acidic aqueous solution. may be added before or after washing with the acidic aqueous solution. Examples include washing with a basic aqueous solution and washing with a saline solution.

In the peptide synthesis using the method of the present invention, the C-terminal carrier-protected peptide is solidified (crystallized) in the stage after deprotection of the Fmoc group, and the C-terminal carrier-protected peptide is solid-liquid separated. may be recovered. Solidification can be carried out by appropriately referring to known methods by changing the composition of the solvent in which the carrier-protected peptide is dissolved. After that, it can be carried out by adding a hydrocarbon solvent such as methanol, acetonitrile, or hexane to change the composition of the solution.

By repeating the above steps Z1 to Z4, a C-terminal carrier-protected peptide having desired amino acid residues is obtained. Finally, the final target peptide is obtained through the step of removing the C-terminal carrier and side chain protecting group [Step Z5].

(Step Z5: deprotection, purification step)
This step is a step of removing the carrier and protecting group of the side chain of the peptide from the C-terminus of the peptide to obtain the desired peptide.

The method for removing the carrier and peptide side chain protecting groups from the peptide C-terminus is not particularly limited, and a known deprotection method may be used, preferably by acid treatment. For example, deprotection methods using trifluoroacetic acid (TFA) can be used.

The peptide from which the carrier and the protecting group of the peptide side chain have been deprotected can be isolated and purified according to a purification method commonly used in peptide synthesis. For example, the target peptide can be isolated and purified by extraction washing, crystallization, and chromatography.

If the method for removing the Fmoc group described above is used for peptide synthesis, the intermediate peptide obtained after deprotection of the Fmoc group can be used in the next condensation step without isolation. This enables one-pot synthesis of peptides and is particularly suitable for industrial production.

<3> Protecting Group Remover The protecting group remover represented by the above formula (Z2) is a composition containing the scavenger represented by the above formula (Z1) and a basic deprotecting agent. . The scavenger and deprotection agents are described above and will not be described in detail here.

〔summary〕
As understood from the above, the method for producing a peptide according to the first aspect of the present invention comprises, in an organic solvent, an amino group-containing compound whose N-terminus is protected with a protecting group having a fluorene skeleton, and the following formula (Z1): a step of contacting with a capturing agent represented by to obtain a capturing body in which a by-product having a fulvene skeleton derived from the protecting group and the capturing agent are bound;
a step of separating the captured body obtained from the organic solvent;
including,
Peptide production method:

The method for producing a peptide according to the second aspect of the present invention comprises, in addition to the configuration of the method for producing a peptide according to the first aspect, an amino group-containing compound having the N-terminus protected with the protecting group and a deprotecting agent. and the step of contacting with.

In the peptide production method according to the third aspect of the present invention, in addition to the configuration of the peptide production method according to the second aspect, the deprotecting agent is 1,8-diazabicyclo[5.4.0] -7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), potassium tert-butoxide, At least one base selected from the group consisting of sodium tert-butoxide, triethylamine, and tributylamine.

A method for producing a peptide according to a fourth aspect of the present invention, in addition to the configuration of the method for producing a peptide according to any one of the above-described first to third aspects, the step of separating the captured body comprises: After washing by adding an acidic aqueous solution to the organic solvent, the organic solvent is separated into an aqueous layer and an organic layer, and then the separated aqueous layer is separated.

In the peptide production method according to the fifth aspect of the present invention, in addition to the configuration of the peptide production method according to any one of the first to fourth aspects described above, The scavenger is at least one selected from the group consisting of morpholine, piperidine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide.

In the method for producing a peptide according to the sixth aspect of the present invention, in addition to the configuration of the method for producing a peptide according to any one of the first to fifth aspects described above, The scavenger is at least one selected from the group consisting of morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide.

The method for removing a protecting group according to the seventh aspect of the present invention comprises, in an organic solvent, an amino group-containing compound whose N-terminus is protected by a protecting group having a fluorene skeleton, and a scavenger represented by the following formula (Z1): and a step of contacting with to obtain a capturing body in which a by-product having a fulvene skeleton derived from the protecting group and the capturing agent are bound;
a step of separating the captured body obtained from the organic solvent;
including,
Methods for removing protecting groups:

The remover according to the eighth aspect of the present invention is an agent for removing a protecting group having a fluorene skeleton, containing a scavenger represented by the following formula (Z1) and a basic deprotecting agent:

In the peptide production method according to the ninth aspect of the present invention, in addition to the configuration of the removing agent according to the eighth aspect described above, the scavenger is morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine , and thiomorpholine dioxide.

In the peptide production method according to the tenth aspect of the present invention, in addition to the configuration of the removing agent according to the eighth or ninth aspect described above, the deprotecting agent comprises 1,8-diazabicyclo[5. 4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, 1,4-diazabicyclo[2.2.2]octane, potassium tert-butoxide, sodium tert-butoxide, At least one base selected from the group consisting of triethylamine and tributylamine.

The benzyl compound (Y1) according to the eleventh aspect of the present invention has the following formula (Y1):

(In the formula,
* indicates the binding position,
R ^1a , R ^1b , R ^1c , R ^1d and R ^1e each independently represent a hydrogen atom or an alkyl group,
n ₁ represents an integer of 0 to 6, and when n ₁ is 1 or more, the repeating unit shown in parentheses to which n ₁ is attached is an alkylene group,
n ₂ represents an integer of 0 or more and 6 or less, and when n ₂ is 1 or more, the repeating unit shown in parentheses to which n ₂ is attached is an alkylene group,
However, at least two or more of R ^1a , R ^1b , R ^1c and R ^1d are hydrogen atoms. )
is a group represented by
k R ² each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom;
X represents a hydroxyl group,
m represents an integer of 2 or 3,
k represents an integer of 0 or more (5-m) or less,
At least one of m [QR ¹ ] is substituted at the meta position with respect to the substituent containing X. ]
is represented by

The benzyl compound (Y1) according to the twelfth aspect of the present invention has a total carbon number of 40 or more and 60 or less in addition to the structure of the benzyl compound (Y1) according to the eleventh aspect described above.

In the benzyl compound (Y1) according to the thirteenth aspect of the present invention, in addition to the configuration of the benzyl compound (Y1) according to the eleventh aspect or the twelfth aspect described above, each of the m R ¹ independently one branched organic group,
The following formula (YA'):

(In the formula,
* indicates the binding position,
R ^1f is a linear alkyl group having 4 to 12 carbon atoms,
R ^1g is a linear alkyl group having 6 to 14 carbon atoms. ) is a group represented by

In the benzyl compound (Y1) according to the fourteenth aspect of the present invention, in addition to the configuration of the benzyl compound (Y1) according to the thirteenth aspect described above, R ^1f is a linear chain having 4 to 10 carbon atoms is an alkyl group in the form of
R ^1g is a linear alkyl group having 6 or more and 12 or less carbon atoms.

A method for producing a peptide according to the fifteenth aspect of the present invention comprises a dissolving step of dissolving the benzyl compound according to any one of the above-described eleventh to fourteenth aspects in a soluble solvent,
Next, a condensation reaction step of condensing the dissolved benzyl compound and an amino acid whose N-terminus is protected by an N-terminal protecting group to produce a first condensate;
Then, a first base is added to the soluble solvent containing the first condensate to scavenge the amino acid active ester, the first base and the second base are added to the soluble solvent, and the second base is added to the soluble solvent. deprotecting the N-terminal protecting group from the condensate of 1 and scavenging by-products derived from the N-terminal protecting group with the first base;
Next, an acidic aqueous solution is added to the soluble solvent containing the captured bodies captured in the scavenging step to wash the solvent, and the aqueous layer and the organic layer are separated to remove the captured bodies and unnecessary substances to the aqueous layer. , a liquid separation step of obtaining a second condensate in which the N-terminal protecting group is deprotected from the first condensate in the organic layer;
including.

In the method for producing a peptide according to the sixteenth aspect of the present invention, in addition to the configuration of the method for producing a peptide according to the fifteenth aspect described above, in the condensation reaction step, the N-terminally unprotected amino acid and The 2n-th condensate comprising an amino acid whose C-terminus is protected by the benzyl compound and the number of residues is n, is condensed with the n-th amino acid whose N-terminus is protected to the ( 2n+1) forming a condensate of
the step of scavenging comprises performing deprotection of the N-terminal protecting group from the (2n+1)th condensate;
The liquid separation step includes a step of obtaining a (2n+2)th condensate in which the N-terminal protecting group is deprotected from the (2n+1)th condensate in the organic layer,
Said n is a natural number of 2 or more.

In the method for producing a peptide according to the 17th aspect of the present invention, n is 5 or more in addition to the configuration of the method for producing a peptide according to the 16th aspect described above.

In the method for producing a peptide according to the eighteenth aspect of the present invention, in addition to the configuration of the method for producing a peptide according to any one of the fifteenth aspect to the seventeenth aspect described above, the separation step includes: The step of adding a ketone-based liquid separation promoting solvent to the soluble solvent is further included.

The benzyl compound (X1) according to the nineteenth aspect of the present invention has the following formula (X1):

[In the formula,
m Q ¹ and Q ² are each an oxygen atom,
m R ¹ are each independently an alkylene group,
m R ² are each independently an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aryl group,
k R ³ are each independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom,
X is a hydroxyl group,
m is an integer of 2 or 3,
k represents an integer from 0 to (5-m). ]
is represented by

In the benzyl compound (X1) according to the twentieth aspect of the present invention, in addition to the configuration of the benzyl compound (X1) according to the nineteenth aspect described above, the m R ^1s have 2 to 16 carbon atoms. is an alkylene group of

In the benzyl compound (X1) according to the twenty-first aspect of the present invention, in addition to the configuration of the benzyl compound (X1) according to the nineteenth aspect or the twentieth aspect, the m R ² are halogen An aryl group having substituents containing atoms.

In the benzyl compound (X1) according to the twenty-second aspect of the present invention, in addition to the configuration of the benzyl compound (X1) according to the nineteenth aspect or the twentieth aspect, the m R ² are carbon It is an alkyl group having a number of 5 or more and 28 or less.

In the benzyl compound (X1) according to the twenty-third aspect of the present invention, in addition to the configuration of the benzyl compound (X1) according to the twenty-second aspect, the m R ² are linear alkyl groups , or an alkyl group having a total of 1 or 2 branched chains, represented by the following formula (XA):

(In the formula,
* indicates the binding position,
R ^2a , R ^2b , R ^2c , R ^2d and R ^2e each independently represent a hydrogen atom or an alkyl group,
n ₁ represents an integer of 0 or more and 16 or less,
_n2 represents an integer of 0 or more and 16 or less.
However, at least two or more of R ^2a , R ^2b , R ^2c and R ^2d are hydrogen atoms. ) is a group represented by

Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these.

First, an example of Embodiment 1 of the present invention described above will be given.

<Manufacturing example>
Example X1
Synthesis of compound (X1-4)

Example (X1-a)
25 g (100 mmol) of 3,5-bistrifluoromethylphenol was dissolved in 125 mL of DMF, 27.6 g (120 mmol) of 11-bromoundecanol and 27.6 g (200 mmol) of potassium carbonate were added, and the mixture was stirred at 60° C. for 4 hours. The reaction solution was returned to room temperature, and solid content was removed by filtration. 150 mL of toluene and 75 mL of 1M hydrochloric acid were added to the filtrate for liquid separation and washing, and the organic layer was further washed with 75 mL of 1M hydrochloric acid and 100 mL of saturated brine. After adding 50 g of sodium sulfate to dry the organic layer, the solvent was distilled off under reduced pressure to obtain 37.2 g of compound (X1-1) (yield 93%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 1.10-1.60 (m, 16H), 1.81-1.90 (m, 2H), 3.63 (t, 2H, J = 2.0Hz) , 4.04(t, 1H, J=6.8Hz), 7.28(s, 2H), 7.43(s, 1H)

Example (X1-b)
24 g (60 mmol) of compound (X1-1) was dissolved in 240 mL of dichloromethane, 20.5 g (78 mmol) of triphenylphosphine and 26.0 g (78 mmol) of carbon tetrabromide were added, and the mixture was stirred at room temperature for 2 hours. 36 g of silica gel was added to the reaction solution, the solvent was distilled off, and the residue was adsorbed on the silica gel. This silica gel was placed on a Kiriyama funnel lined with filter paper, and washed with 480 mL of an organic solvent (hexane:ethyl acetate=90:10) to elute the desired product. By distilling off the solvent under reduced pressure, 27.0 g of compound (X1-2) was obtained (yield 97%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 1.10-1.60 (m, 12H), 1.81-1.90 (m, 4H), 3.41 (t, 2H, J = 6.8Hz) , 4.02(t, 1H, J=6.4Hz), 7.29(s, 2H), 7.44(s, 1H)

Example (X1-c)
1.16 g (6.33 mmol) of methyl gallate was dissolved in 150 mL of DMF, 14.1 g (30.4 mmol) of compound (X1-2) and 16.6 g (120 mmol) of potassium carbonate were added, and the mixture was stirred at 60° C. for 18 hours. . After the potassium carbonate was removed by filtration, 100 mL of 1M hydrochloric acid and 100 mL of hexane were added to the reaction solution for liquid separation and washing, and the organic layer was further washed with 100 mL of 5% sodium hydrogen carbonate and 20% brine. After drying the organic layer with sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=98:2-85:15) to obtain 6.7 g of compound (X1-3) (yield 79.6%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 1.20-1.60 (m, 48H), 1.81-1.90 (m, 6H), 3.87 (s, 3H), 3.95-4 .05 (m, 12H), 7.21 (s, 2H), 7.28 (s, 6H), 7.42 (s, 3H)

Example (X1-d)
6.2 g (4.66 mmol) of compound (X1-3) was dissolved in 150 mL of THF, 20.96 mL of lithium triethylborohydride (1 MTHF solution, 20.96 mmol) was added under ice cooling, and the mixture was stirred at room temperature for 2 hours. Water (50 mL) and 20 mL of 1 M hydrochloric acid were added to the reaction solution to stop the reaction, and 200 mL of ethyl acetate was added to perform liquid separation and washing, and the organic layer was washed twice with 100 mL of water. After drying the organic layer with sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=90:10-60:40) to obtain 3.8 g of compound (X1-4) (yield 61.2%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 1.20-1.60 (m, 48H), 1.81-1.90 (m, 6H), 3.90-4.05 (m, 12H), 4 .59 (d, 2H), 6.54 (s, 2H), 7.28 (s, 6H), 7.42 (s, 3H)
ESI-MS: 1303.77 [M ⁺ ]

Example X2
Synthesis of compound (X2-3)

Example (X2-a)
Dissolve 8 g (26.79 mmol) of 2-n-octyl-1-dodecanol in 210 mL of toluene (anhydrous), add 17.6 g (53.59 mmol) of dibromododecane and 2.14 g (53.59 mmol) of NaH, and stir at 105°C. Stirred overnight. The reaction solution was returned to room temperature, 10 mL of 1M hydrochloric acid was added, and the mixture was stirred for 10 minutes. 90 mL of 1M hydrochloric acid was added to the reaction solution to perform liquid separation washing, and the organic layer was washed with 100 mL of saturated brine three times, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane-hexane:ethyl acetate=90:10) to obtain 8.8 g of compound (X2-1) (yield 60.1%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 6H, J = 7.6 Hz), 1.20-1.59 (m, 51H), 1.81-1.89 (m, 2H) , 3.25 (d, 2H, J=6.0Hz), 3.35-3.43 (m, 4H)

Example (X2-b)
0.77 g (5.61 mmol) of 2,4-dihydroxybenzaldehyde was dissolved in 116 mL of a mixed solvent of DMF:cyclopentyl methyl ether (1:1), and 7.6 g (14.03 mmol) of compound (X2-1) and potassium carbonate were dissolved. 3.9 g (28.06 mmol) was added and stirred at 90° C. for 3 hours. After the potassium carbonate was removed by filtration, 100 mL of 1M hydrochloric acid and 100 mL of hexane were added to the reaction solution for liquid separation and washing, and the organic layer was further washed with 100 mL of 5% sodium hydrogen carbonate and 20% brine. After drying the organic layer with sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane-hexane:ethyl acetate=90:10) to obtain 4.4 g of compound (X2-2) (yield 73.9%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 12H, J = 6.6 Hz), 1.20-1.59 (m, 102H), 1.74-1.88 (m, 4H) , 3.25 (d, 4H, J = 6.6Hz), 3.36 (t, 4H, J = 6.6Hz), 3.98-4.05 (m, 4H), 6.41 (d, 1H, J = 2.4Hz), 6.51 (dd, 1H, J = 2.4Hz, 8.6Hz), 7.79 (d, 1H, J = 8.6Hz), 10.33 (s, 1H )

Example (X2-c)
4.4 g (4.08 mmol) of compound (X2-2) was dissolved in 65 mL of a mixed solvent of THF (anhydrous):methanol (10:3), and 0.31 g (8.17 mmol) of sodium borohydride was dissolved under ice-cooling. was added and stirred for 10 minutes, the ice bath was removed, and the mixture was stirred at room temperature for 1 hour. 5 mL of acetone was added to the reaction solution to stop the reaction, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=96:4-hexane:ethyl acetate=90:10) to obtain 3.9 g of compound (X2-3) (yield 89.9%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 12H, J = 6.5 Hz), 1.20-1.59 (m, 102H), 1.72-1.85 (m, 4H) , 2.24 (t, 1H), 3.25 (d, 4H, J = 6.5Hz), 3.36 (t, 4H, J = 6.5Hz), 3.90-4.01 (m, 4H), 4.61 (d, 2H, J = 6.5Hz), 6.41 (dd, 1H, J = 2.7Hz, 8.4Hz), 6.45 (d, 1H, 8.4Hz), 7.13(d, 1H)
ESI-MS: 1069.13 [M ⁺ ]

Example X3
Compound (Synthesis of X3-2)

Example (X3-a)
0.79 g (4.29 mmol) of methyl gallate was dissolved in 132 mL of a mixed solvent of DMF:MTHP (1:1), and 8.8 g of compound (X2-1) prepared in Example (X2-a) (16. 12 mmol) and 2.65 g (19.17 mmol) of potassium carbonate were added, and the mixture was stirred at 90°C overnight. After the potassium carbonate was removed by filtration, 100 mL of 1M hydrochloric acid and 100 mL of hexane were added to the reaction solution for liquid separation and washing, and the organic layer was further washed with 100 mL of 5% sodium hydrogen carbonate and 20% brine. After drying the organic layer with sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane-hexane:ethyl acetate=90:10) to obtain 4.1 g of compound (X3-1) (yield 61.1%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 18H, J=6.3 Hz), 1.20-1.86 (m, 147H), 3.24 (d, 6H, J=6. 3Hz), 3.36 (t, 6H, J = 6.3Hz), 3.88 (s, 3H), 3.98-4.40 (m, 6H), 7.24 (s, 2H)

Example (X3-b)
3.2 g (2.04 mmol) of compound (X3-1) was dissolved in 30 mL of THF (anhydrous), and 4.1 mL of diisobutylaluminum hydride (1.5 M toluene solution, 6.16 mmol) was added under ice-cooling. The mixture was stirred for 1 hour and stirred at room temperature for an additional 2 hours. After 5 mL of acetone was added to the reaction solution to stop the reaction, 30 g of silica gel was added and the mixture was stirred at room temperature for 15 minutes, the reaction solution was filtered, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=96:4-hexane:ethyl acetate=85:15) to obtain 2.3 g of compound (X3-2) (yield 72.5%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 18H, J = 6.6 Hz), 1.18-1.84 (m, 147H), 3.25 (d, 6H, J = 6.6 Hz). 6Hz), 3.36 (t, 6H, J = 6.6Hz), 3.60-3.66 (m, 1H), 3.90-4.00 (m, 6H), 4.59 (d, 2H, J = 6.6 Hz), 6.55 (s, 2H)
ESI-MS: 1549.41 [M ⁺ ]

Example X4
Synthesis of compound (X4-3)

Example (X4-a)
Dissolve 1 g (2.81 mmol) of 2-decyl-1-tetradecanol in 20 mL of toluene (anhydrous), add 1.85 g (5.63 mmol) of dibromododecane and 0.226 g (5.63 mmol) of NaH, and stir at 95°C. Stirred overnight. The reaction solution was returned to room temperature, 10 mL of 1M hydrochloric acid was added, and the mixture was stirred for 10 minutes. 20 mL of hexane was added to separate and wash, and the organic layer was washed twice with 40 mL of saturated brine, dried over an appropriate amount of sodium sulfate, filtered, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane-hexane:ethyl acetate=90:10) to obtain 1.18 g of compound (X4-1) (yield 70.0%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 6H, J = 6.8 Hz), 1.15-1.60 (m, 55H), 1.81-1.89 (m, 2H) , 3.25 (d, 2H, J=6.3Hz), 3.35-3.42 (m, 4H)

Example (X4-b)
0.106 g (0.77 mmol) of 2,4-dihydroxybenzaldehyde was dissolved in 17.4 mL of a mixed solvent of DMF: cyclopentyl methyl ether (1:1) to obtain 1.16 g (1.92 mmol) of compound (X4-1), 0.532 g (3.85 mmol) of potassium carbonate was added and stirred at 90° C. for 4 hours. After potassium carbonate was removed by filtration, 20 mL of hexane and 36 mL of 1M hydrochloric acid were added to the reaction solution for liquid separation and washing, and the organic layer was washed twice with 18 mL of 5% sodium hydrogen carbonate and 18 mL of 20% brine. After drying the organic layer with an appropriate amount of sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane-hexane:ethyl acetate=90:10) to obtain 0.33 g of compound (X4-2) (yield 72.6%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, 12H, J = 7.5 Hz), 1.15-1.60 (m, 118H), 1.74-1.88 (m, 4H) , 3.25 (d, 4H, J = 6.2Hz), 3.36 (t, 4H, J = 6.2Hz), 3.98-4.05 (m, 4H), 6.41 (d, 1H, J = 2.5Hz), 6.51 (dd, 1H, J = 3.1Hz, 9.2Hz), 7.79 (d, 1H, J = 8.9Hz), 10.33 (s, 1H )

Example (X4-c)
1.0 g (0.837 mmol) of compound (X4-2) was dissolved in 19.5 mL of a mixed solvent of THF (anhydrous):methanol (10:3), and 0.070 g of sodium borohydride (1.0 g of sodium borohydride) was dissolved under ice-cooling. 850 mmol) was added and stirred for 10 minutes, the ice bath was removed, and the mixture was stirred at room temperature for 1 hour. 4 mL of acetone was added to the reaction solution to terminate the reaction, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=90:10) to obtain 0.55 g of compound (X4-3) (yield 55.6%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.87 (t, 12H, J = 6.5 Hz), 1.16-1.58 (m, 118H), 1.71-1.83 (m, 4H) , 2.24 (t, 1H, J = 6.5Hz), 3.24 (d, 4H, J = 6.2Hz), 3.35 (t, 4H, J = 6.2Hz), 3.88- 4.00 (m, 4H), 4.59 (d, 2H, J = 6.5Hz), 6.40 (dd, 1H, J = 2.2Hz, 8.2Hz), 6.44 (d, 1H , J = 2.2 Hz), 7.11 (d, 1H, J = 8.2 Hz)
ESI-MS: 1181.07 [M ⁺ ]

Example X5
<Confirmation of solubility of tag in organic solvent>
Compound (X1-4) produced in Example X1, compound (X2-3) produced in Example X2, compound (X3-2) produced in Example X3, and compound (X4- The solubility (25°C) in various solvents of 3) was measured.

〔experimental method〕
The compounds of Examples X1 to X4 and the straight chain-containing compounds as comparative examples (see Comparative Examples X1 and X2 in Table X2) were saturated in each solvent at 25° C., and their solubility (unit: weight %) was measured. (Tables X1, X2). Solvents used were CPME, MTHP, toluene, and chloroform.

The linear C ₁₈ H ₃₇ compound _shown in Comparative Example X1 was prepared by the method described in Examples of JP _- A-2000-44494. , (2011), 4476-4479 was synthesized with reference to the method described in 4476-4479 was used.

Table X1 shows Example X1 (Compound (X1-4)), Example X2 (Compound (X2-3)), Example X3 (Compound (X3-2)), and Example X4 (Compound (X4-3 )) solubility results. Table X2 shows the solubility results of Comparative Example X1 and Comparative Example X2. The value in parentheses in Table X2 indicates how many times the solubility of Examples X1 to X4 corresponds to the solubility of the compounds of Examples X1 to X4 when it is assumed that the solubility of the compounds of Examples X1 to X4 is uniformly 50 (% by weight) (i.e., 50 divided by the solubility).

〔Experimental result〕
All of the compounds of Examples X1 to X4 had solubility values greater than 50 (% by weight). On the other hand, the compounds of Comparative Examples X1 and X2 were both less than 50 (mass%), and the maximum remained at 20.0 (mass%) (Comparative Example X2, chloroform). Further, as shown in Table X2, the solubility of the compounds of Examples X1 to X4 is at least 2.5 times greater than the solubility of the compounds of Comparative Examples X1 and X2, even if the difference is small (Comparative Example X2- See the ratio with chloroform), and the large difference was more than 17.2 times (see Comparative Example X1-the ratio with toluene).
As can be seen, all of the compounds of Examples X1-X4 are 2.5-fold to 17-fold higher than the compounds described in Comparative Examples X1 and X2, in which the corresponding side chains are linear, in various solvents. It was confirmed that the high solubility was more than doubled. From this, it was found that the above compound can function as an excellent tag in peptide synthesis in the peptide production method.

Example X6-1
<Confirmation of hydrophobicity of tag>
Liquid chromatography (HPLC) was used to evaluate the hydrophobicity of the compounds of Examples X1 to X4 of the present invention.

〔experimental method〕
A 10 mg/10 mL (THF) solution of each of the tag according to one aspect of the present invention (the compounds of Examples X1 to X4), the linear C ₁₈ H ₃₇ compound of Comparative Example X1, and the linear C ₂₂ H ₄₅ compound of Comparative Example X2. was adjusted, and the retention times (elution times) of liquid chromatography (HPLC) under the following conditions were compared (Table X3).

Liquid chromatography (HPLC) conditions:
Column: Inert Sustain C18 (3 μm, 4.6×125 mm)
Mobile phase B: THF, mobile phase A: 0.1% trifluoroacetic acid aqueous solution Eluate: mobile phase A / mobile phase B = 25/75 (isocratic)
Flow rate: 1.0 mL/min
Column temperature: 40°C
Detector: UV-visible spectroscopic detector (λ=220 nm)

〔Experimental result〕
As shown in Table X3, the compounds of Comparative Examples X1 and X2 had retention times of 13.6 minutes and 12.1 minutes, respectively, while Examples X1-X4 had retention times of 8.4 minutes, respectively. minutes, 21.8 minutes, 60.2 minutes, and 33.2 minutes. All of Examples X2 to X4 greatly exceeded the retention times of Comparative Examples X1 and X2. In Example X1, although the retention times were smaller than those of Comparative Examples X1 and X2, they were kept at approximately the same level.

As described above, the compounds of Examples X1 to X4 all showed retention times equal to or longer than those of the compounds of Comparative Examples X1 and X2, in which the corresponding side chains were linear chains. In a method of manufacture, we have found that the compounds described above can serve as excellent tags in peptide synthesis.

Example X6-2
<Acid resistance>
The stability of the side chain portion of the compound of the present invention against acid was evaluated using the compound (X1-4) produced in Example X1 and the compound (X3-2) produced in Example X3.

〔experimental method〕
50 mg of compound (X1-4) and compound (X3-2) of the present invention are each weighed into a sealed sample tube container, 0.5 mL of 1 wt% HCl/CPME is added thereto, and each compound when stirred at room temperature The HPLC peak purity (%) of the solution was confirmed to change over time to evaluate the stability. In addition, a solution having the same concentration as the above was prepared with only CPME containing no hydrogen chloride gas, and the purity (%) of this solution was used as the initial value. Table X4 shows the initial value and the HPLC purity % of compound (X1-4) and compound (X3-2) of the present invention after stirring for 3 hours.

Liquid chromatography (HPLC) conditions:
Column: Inert Sustain C18 (3 μm, 4.6×125 mm)
Mobile phase B: THF, mobile phase A: 0.1% trifluoroacetic acid aqueous solution Eluate: mobile phase A/mobile phase B: measurement was performed under the gradient conditions shown in Table X5.

Flow rate: 1.0 mL/min
Column temperature: 40°C
Detector: UV-visible spectroscopic detector (λ=220 nm)

〔Experimental result〕
As shown in Table X4, both the compounds of Examples X1 and X3 were stable against acid even after 3 hours. Non-Patent Document 5 discloses that the half-life of a triisopropylsilyl group to an acidic solvent (1 wt % hydrochloric acid/methanol) is 55 minutes. It was suggested that the compounds of Examples X1 and X3 are more stable to acid than compounds having at least an O--Si bond.

As described above, when the peak changes over time in the liquid chromatography of the compounds of Examples X1 and X3 were confirmed, no decomposition was observed in any of them. I found that it can function as

<Example of peptide synthesis>
Peptide synthesis was carried out using compound (X1-4) and compound (X2-3) of the present invention. Hereinafter, in the formulas, compound (X1-4) is also referred to as HO-Tag (X1-4), and compound (X2-3) is also referred to as HO-Tag (X2-3). That is, Tag (X1-4) indicates a portion obtained by removing —OH from compound (X1-4), and Tag (X2-3) indicates a portion obtained by removing —OH from compound (X2-3).

Example X7: Synthesis of H-Tyr(OtBu)-Ile-Leu-OTag (X1-4) Example X7-1: Synthesis of HO-Leu-OTag (X1-4) Compound (X1-4) 1.3 g (1.0 mmol) was dissolved in 20 mL of a mixed solution of MTHP/DMF (8/2), Fmoc-Leu-OH 0.46 g (1.3 mmol), EDCI.HCl 0.25 g (1.3 mmol) and DMAP 0.012 g ( 0.1 mmol) was added and stirred at room temperature for 4 hours. 39 μL (0.4 mmol) of morpholine was added and stirred at room temperature for 30 minutes. 1.74 mL (20.0 mmol) of morpholine and 1.04 mL (7.0 mmol) of DBU were added and stirred at room temperature for 1 hour. Under ice-cooling, 8.3 mL of 6 M hydrochloric acid was added, and 23.4 mL of 0.1 M hydrochloric acid was further added to separate the layers. The organic layer was washed with 10 mL of 2M hydrochloric acid and 23.4 mL of 0.5M aqueous sodium hydrogencarbonate solution, and the layers were separated. The organic layer was dried over an appropriate amount of sodium sulfate and then filtered. 4)) was obtained as a solution.

Example X7-2: Synthesis of HO-Ile-Leu-OTag (X1-4) To the solution of HO-Leu-OTag (X1-4) obtained above, 4 mL of DMF, 0.46 g of Fmoc-Ile-OH (1. 3 mmol), 0.25 g (1.3 mmol) of EDCI.HCl and 0.046 g (0.3 mmol) of Oxyma were added and stirred at room temperature for 1 hour. 39 μL (0.4 mmol) of morpholine was added and stirred at room temperature for 30 minutes. 1.74 mL (20.0 mmol) of morpholine and 1.04 mL (7.0 mmol) of DBU were added and stirred at room temperature for 1 hour. Under ice-cooling, 8.3 mL of 6 M hydrochloric acid was added, and 23.4 mL of 0.1 M hydrochloric acid was further added to separate the layers. The organic layer was washed with 10 mL of 2M hydrochloric acid and 23.4 mL of 0.5M aqueous sodium hydrogencarbonate solution, and the layers were separated. The organic layer was dried over an appropriate amount of sodium sulfate, filtered, and an amino acid condensate (HO-Ile-Leu-OTag ( X1-4)) were obtained as solutions.

Example X7-3: Synthesis of H-Tyr(OtBu)-Ile-Leu-OTag (X1-4) Same as Example X7-2 except that Fmoc-Tyr(OtBu)-OH was used as the amino acid to be condensed. Working up, H-Tyr(OtBu)-Ile-Leu-OTag (X1-4) was obtained as a solution. The solvent was distilled off from the resulting organic layer under reduced pressure to obtain 1.58 g of H-Tyr(OtBu)-Ile-Leu-OTag (X1-4) (yield 90.3%).
ESI-MS: 1749.13 [M+H] ⁺

Since H-Tyr(OtBu)-Ile-Leu-OTag (X1-4) was obtained in high yield, by using a specific cyclic amine containing only one nitrogen atom such as morpholine as a scavenger, It was confirmed that the by-product could be easily removed.

Using a small amount of this compound, the tag was deprotected with a mixed solution of trifluoroacetic acid (TFA): water = 9.5:0.5 and analyzed. : 408.24 [M+H] ⁺ was confirmed.

Example X8: Synthesis of H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(OtBu)-Ile-Leu-OTag(X2-3) 0.5 g (0.46 mmol) of compound (X2-3) as a tag ) and the amino acids shown below from the 1st residue to the 6th residue, performing the same operations as in Examples X7-1 to Example X7-3,
H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(OtBu)-Ile-Leu-OTag (X2-3) was obtained as a solution.

The solvent was distilled off from the obtained organic layer under reduced pressure, and H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(OtBu)-Ile-Leu-OTag(X2-3) 0.80 g (yield 70.6%) was obtained.
ESI-MS: 2430.23 [M+H] ⁺

Using a small amount of this compound, tagging was performed with a mixed solution of trifluoroacetic acid (TFA): water: thioanisole: 1,2-ethanediol: phenol = 10: 0.5: 0.5: 0.25: 0.75. was deprotected and analyzed, ESI-MS of H-Arg-Arg-Pro-Tyr-Ile-Leu-OH: 817.50 [M+H] ⁺ was confirmed.

[Tag manufacturing]
Next, an example of Embodiment 2 of the present invention described above will be given.
<Example Y1>

Example (Y1-a)
1.20 g (6.516 mmol) of methyl gallate was dissolved in 12 mL of DMF and 12 mL of cyclopentyl methyl ether (CPME), and 7.15 g (29.322 mmol) of 5-bromomethylundecane and 4.50 g (32.580 mmol) of potassium carbonate were added. The mixture was added and stirred at 110° C. for 10 hours. The reaction liquid was returned to room temperature, and the solid content was removed by filtration. 20 mL of CPME and 20 mL of 1M hydrochloric acid were added to the filtrate to perform liquid separation washing, and further, 20 mL of 5% sodium hydrogen carbonate and 20 mL of 20% brine were washed. After an appropriate amount of sodium sulfate was added to dry the organic layer, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=97:3-90:10) to obtain 3.8 g of compound (Y1-1) (yield 84.6%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.84-0.96 (m, 18H), 1.20-1.60 (m, 66H), 1.71-1.85 (m, 3H), 3 .86-3.92 (m, 9H), 7.24 (s, 2H)
Example (Y1-b)
2.42 g (3.511 mmol) of compound (Y1-1) was dissolved in 48 mL of THF, and 7.0 mL of diisobutylaluminum hydride (1.5 M toluene solution, 10.533 mmol) was added dropwise under ice cooling. Stirred for 2 hours. 10 mL of 0.2 M hydrochloric acid was added to the reaction solution to terminate the reaction, and the solvent was distilled off under reduced pressure. After adding 100 mL of ethyl acetate to the residue, the mixture was washed twice with 75 mL of 1M hydrochloric acid, and then separated and washed with 50 mL of 5% sodium hydrogen carbonate and 50 mL of 20% brine. After drying the organic layer with an appropriate amount of sodium sulfate, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (hexane/ethyl acetate=95:5 to 90:10) to give compound (Y1-2). 1.86 g (80.2% yield) was obtained.
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.84-0.94 (m, 18H), 1.22-1.64 (m, 66H), 1.72-1.84 (m, 3H), 3 .75-3.88 (dd, J=7.2Hz, 14.4Hz, 6H), 4.60 (d, J=7.2Hz, 2H), 6.54 (s, 2H)
ESI-MS: 683.54 [M+Na] ⁺

Example (Y2-a)
3.01 g (16.357 mmol) of methyl gallate was dissolved in 30 mL of DMF and 30 mL of CPME, 19.98 g (65.428 mmol) of 7-bromomethylpentadecane and 11.30 g (81.785 mmol) of potassium carbonate were added, and the mixture was stirred at 110°C for 12 hours. Stirred for hours. The reaction liquid was returned to room temperature, and the solid content was removed by filtration. 30 mL of CPME and 60 mL of 1M hydrochloric acid were added to the filtrate to perform liquid separation washing, and further, 60 mL of 5% sodium hydrogen carbonate and 60 mL of 20% brine were washed. After an appropriate amount of sodium sulfate was added to dry the organic layer, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=96:4) to obtain 10.09 g of compound (Y2-1) (yield 71.9%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.83-0.94 (m, 18H), 1.20-1.58 (m, 72H), 1.70-1.85 (m, 3H), 3 .85-3.92 (m, 9H), 7.24 (s, 2H)

Example (Y2-b)
10.08 g (11.755 mmol) of compound (Y2-1) was dissolved in 120 mL of anhydrous THF, and 23.5 mL of diisobutylaluminum hydride (1.5 M toluene solution, 35.267 mmol) was added dropwise under ice cooling. , and stirred for 2 hours. 10 mL of 0.2 M hydrochloric acid was added to the reaction solution to terminate the reaction, and the solvent was distilled off under reduced pressure. After adding 150 mL of ethyl acetate to the residue, the mixture was washed twice with 75 mL of 1M hydrochloric acid, and then separated and washed with 75 mL of 5% sodium hydrogen carbonate and 75 mL of 20% brine. After drying the organic layer with an appropriate amount of sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=95:5-85:15) to obtain 7.43 g of compound (Y2-2) (yield 76.4%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.88 (t, J = 6.0 Hz, 18H), 1.20-1.60 (m, 72H), 1.72-1.84 (m, 3H) , 3.75-3.88 (dd, J = 6.0 Hz, 12.0 Hz, 6H), 4.60 (d, J = 6.0 Hz, 2H), 6.54 (s, 2H)
ESI-MS: 829.74 [M+H] ⁺

Example (Y3-a)
0.50 g (2.715 mmol) of methyl gallate was dissolved in 5 mL of DMF and 5 mL of CPME, 4.62 g (11.064 mmol) of 11-bromomethyltricosane and 1.88 g (13.602 mmol) of potassium carbonate were added, and the mixture was heated at 110°C. Stirred for 10 hours. The reaction liquid was returned to room temperature, and the solid content was removed by filtration. 20 mL of hexane and 20 mL of 1M hydrochloric acid were added to the filtrate to perform liquid separation washing, and the filtrate was further washed with 20 mL of 5% sodium hydrogen carbonate and 20 mL of 20% brine. After an appropriate amount of sodium sulfate was added to dry the organic layer, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=98:2-95:5) to obtain 2.64 g of compound (Y3-1) (yield 81.5%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.84-0.91 (m, 18H), 1.20-1.56 (m, 120H), 1.70-1.84 (m, 3H), 3 .85-3.92 (m, 9H), 7.24 (s, 2H)
Example (Y3-b)
2.60 g (2.177 mmol) of compound (Y3-1) was dissolved in 40 mL of THF, and 4.4 mL of diisobutylaluminum hydride (1.5 M toluene solution, 6.531 mmol) was added dropwise under ice cooling. Stirred for 2 hours. 4 mL of 0.2 M hydrochloric acid was added to the reaction solution to terminate the reaction, and the solvent was distilled off under reduced pressure. After adding 40 mL of ethyl acetate to the residue, the mixture was washed twice with 20 mL of 1M hydrochloric acid, and then separated and washed with 20 mL of 5% sodium hydrogen carbonate and 20 mL of 20% brine. After drying the organic layer with an appropriate amount of sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=95:5-90:10) to obtain 2.08 g of compound (Y3-2) (yield 82.3%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.84-0.92 (m, 18H), 1.20-1.60 (m, 72H), 1.72-1.84 (m, 3H), 3 .80 (dd, J=7.0Hz, 14.0Hz, 6H), 4.60 (d, J=7.0Hz, 2H), 6.54 (s, 2H)
ESI-MS: 1166.10 [M ⁺ +H]

Example (Y4-a)
1.35 g (8.0 mmol) of methyl 3,5-dihydroxybenzoate was dissolved in 70 mL of DMF, 8.0 g (19.2 mmol) of 11-bromomethyltricosane and 3.32 g (24.0 mmol) of potassium carbonate were added, Stirred at 90° C. for 7 hours. After potassium carbonate was removed by filtration, 100 mL of water and 100 mL of ethyl acetate were added to the filtrate to separate and wash, and the organic layer was successively washed with 100 mL of water and 100 mL of 20% brine. After drying the organic layer with sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=98:2-80:20) to obtain 4.8 g of compound (Y4-1) (yield 71.0%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.83-1.00 (m, 12H), 1.32-1.61 (m, 80H), 1.81-1.90 (m, 2H), 3 .75-3.85 (m, 4H), 3.90 (s, 3H), 6.34 (s, 1H), 7.15 (s, 2H)

Example (Y4-b)
4.8 g (5.68 mmol) of compound (Y4-1) was dissolved in 80 mL of THF, 11.4 mL of diisopropylaluminum hydride (1.5 M toluene solution, 17.0 mmol) was added under ice cooling, and the mixture was stirred at room temperature for 3 hours. . A 10% Rochelle salt aqueous solution (100 mL) was added to the reaction solution to stop the reaction, and then 200 mL of ethyl acetate was added to perform liquid separation and washing, and the organic layer was washed twice with 100 mL of water. After drying the organic layer with sodium sulfate, the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=95:5-80:20) to obtain 3.5 g of compound (Y4-2) (yield 75.7%).
¹ H-NMR (400 MHz, CDCl ₃ ) δ 0.83-1.00 (m, 12H), 1.32-1.61 (m, 80H), 1.81-1.90 (m, 2H), 3 .80 (d, 4H, J=5.2Hz), 4.62 (s, 2H), 6.38 (s, 1H), 6.50 (s, 2H)
ESI-MS: 813.74 [M+H] ⁺

[Confirmation of solubility of tag in organic solvent]
<Example Y5>
The compound (Y1-2) produced in Example Y1, the compound (Y2-2) produced in Example Y2, the compound (Y3-2) produced in Example Y3, and the compound (Y4- The solubility (25°C) in various solvents of 2) was measured.

〔experimental method〕
Compounds (Y1-2), (Y2-2), (Y3-2) and (Y4-2) of Examples Y1 to Y4, and straight chain-containing compounds as comparative examples (see Comparative Examples Y1 and Y2 in Table Y2 ) was saturated in each solvent at 25° C., and the solubility (unit: weight %) was measured (Tables Y1 and Y2). Solvents used were CPME, MTHP, toluene, and chloroform.

The linear C ₁₈ H ₃₇ compound shown in Comparative Example Y1 was produced by the method described in Examples of JP-A-2000-44493, and the linear C ₂₂ H ₄₅ compound shown in Comparative Example Y2 was produced by the method described in Bioorganic & Medicinal chemistry letters, 21. , (2011), 4476-4479 was synthesized with reference to the method described in 4476-4479 was used.

Table Y1 shows Example Y1 (Compound (Y1-2)), Example Y2 (Compound (Y2-2)), Example Y3 (Compound (Y3-2)), and Example Y4 (Compound (Y4-2 )) solubility results. Table Y2 shows the solubility results of Comparative Examples Y1 and Y2. The values in parentheses in Table Y2 indicate how many times the solubility of Examples Y1 to Y4 corresponds to the solubility of the compounds of Examples Y1 to Y4 when it is assumed that the solubility of the compounds of Examples Y1 to Y4 is uniformly 50 (% by weight) (that is, 50 divided by the solubility).

〔Experimental result〕
All of the compounds of Examples Y1 to Y4 had a solubility greater than 50 (% by weight). On the other hand, the compounds of Comparative Examples Y1 and Y2 were both less than 50 (mass%), and the maximum remained at 12.4 (mass%) (Comparative Example Y1, chloroform). Further, as shown in Table Y2, the solubility of the compounds of Examples Y1 to Y4 is at least 4.0 times greater than the solubility of the compounds of Comparative Examples Y1 and Y2, even if the difference is small (Comparative Example Y1- See the ratio with chloroform), and those with a large difference were greater than 38.5 times (see the ratio with comparative example Y2-toluene).

As described above, all of the compounds of Examples Y1 to Y4 are 4.0 times to 38 times higher than the compounds of Comparative Examples Y1 and Y2, in which the corresponding side chains are linear, in various solvents. 0.5 times higher solubility was confirmed. From this, it was found that the above compound can function as an excellent tag in peptide synthesis in the peptide production method.

[Confirmation of tag hydrophobicity]
<Example Y6>
Hydrophobicity of compounds (Y1-2), (Y2-2), (Y3-2) and (Y4-2) of Examples Y1 to Y4 was evaluated using liquid chromatography (HPLC).

〔experimental method〕
Compounds (Y1-2), (Y2-2), (Y3-2) and (Y4-2) of Examples Y1 to Y4, linear C ₁₈ H ₃₇ compound of Comparative Example Y1 and linear C of Comparative Example Y2 A 10 mg/10 mL (THF) solution of each ₂₂ H ₄₅ compound was prepared, and the retention times (elution times) of liquid chromatography (HPLC) under the following conditions were compared (Table Y3).

〔Experimental result〕
As shown in Table Y3, the compounds (Y3-2) and (Y4-2) according to Examples Y3 and Y4 exhibited higher hydrophobicity than Comparative Examples Y1 and Y2. In addition, the compound (Y2-2) according to Example Y2 exhibited approximately the same level of hydrophobicity as compared with Comparative Examples Y1 and Y2. In contrast, the hydrophobicity of the compound (Y1-2) according to Example Y1 was not as high as those of Comparative Examples Y1 and Y2.

[Example of peptide synthesis]
Peptide synthesis was carried out using compound (Y2-2) and compound (Y3-2). Hereinafter, in the formulas, the compound (Y2-2) is also referred to as HO-Tag (Y2-2), and the compound (Y3-2) is also referred to as HO-Tag (Y3-2). That is, Tag (Y2-2) indicates a portion obtained by removing —OH from compound (Y2-2), and Tag (Y3-2) indicates a portion obtained by removing —OH from compound (Y3-2).

Example Y7: PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu -Synthesis of OTag (Y2-2)

Example Y7-1: Synthesis of HO-Leu-OTag (Y1-4) 1.0 g (1.21 mmol) of compound (Y2-2) was dissolved in 25 mL of a mixture of MTHP/acetonitrile (8/2), and Fmoc -Leu-OH 0.554 g (1.57 mmol), EDCI.HCl 0.30 g (1.57 mmol) and DMAP 0.0147 g (0.121 mmol) were added and stirred at room temperature for 2 hours. 42.2 μL (0.482 mmol) of morpholine was added and stirred at room temperature for 30 minutes. 2.11 mL (24.1 mmol) of morpholine and 1.26 mL (8.44 mmol) of DBU were added and stirred at room temperature for 1 hour. The reaction solution was transferred to a separating funnel, and 18 mL of 20% saline solution was added twice to wash and separate the solution. Further, the organic layer was washed with 18 mL of 2M hydrochloric acid 3 times and separated, and further washed with 18 mL of 0.5M sodium hydrogencarbonate aqueous solution and separated. After the organic layer was dried with an appropriate amount of sodium sulfate, it was filtered while washing with an appropriate amount of MTHP to obtain an amino acid condensate (HO-Leu-OTag (Y2-2)) as a solution.

Example Y7-2: Synthesis of HO-Ile-Leu-OTag (Y2-2) To the solution of HO-Leu-OTag (Y2-2) obtained above was added 5.0 mL of acetonitrile and 0.511 g of Fmoc-Ile-OH. (1.45 mmol), 0.277 g (1.45 mmol) of EDCI.HCl and 0.0514 g (0.362 mmol) of Oxyma were added and stirred at room temperature for 1 hour. 42.2 μL (0.482 mmol) of morpholine was added and stirred at room temperature for 30 minutes. 2.11 mL (24.1 mmol) of morpholine and 1.26 mL (8.44 mmol) of DBU were added and stirred at room temperature for 1 hour. The reaction solution was transferred to a separating funnel, and 18 mL of 20% saline solution was added twice to wash and separate the solution. Further, the organic layer is washed with 18 mL of 2M hydrochloric acid 3 times and separated, further washed with 18 mL of 0.5M sodium hydrogen carbonate aqueous solution, separated, and the organic layer is dried with an appropriate amount of sodium sulfate, and then added with an appropriate amount of MTHP. It was filtered while washing with , to obtain an amino acid condensate (HO-Ile-Leu-OTag (Y2-2)) as a solution.

Example Y7-3: Synthesis of H-Tyr(tBu)-Ile-Leu-OTag (Y2-2) Same as Example Y7-2 except that Fmoc-Tyr(tBu)-OH was used as the amino acid to be condensed. After working up, H-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-4: Synthesis of H-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) The same procedure as in Example Y7-2 except that Fmoc-Pro-OH was used as the amino acid to be condensed. was carried out to obtain H-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) as a solution.

Example Y7-5: Synthesis of H-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) The same operation as in Example Y7-2 was performed except that MTHP/DMF (8/2) was used as the solvent, and H-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2 ) was obtained as a solution.

Example Y7-6: Synthesis of H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) In addition, the same operation as in Example Y7-2 was performed except that MTHP/DMF (8/2) was used as the reaction solvent, and H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu) -Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-7: Synthesis of H-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) Using Fmoc-Pro-OH as the amino acid to be condensed , In addition, the same operation as in Example Y7-2 was performed except that 2 mL of acetone was added during the third 2M hydrochloric acid separation to separate the liquids, and H-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr (tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-8: Synthesis of H-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Y2-2) The same procedure as in Example Y7-2 was carried out, except that Lys(Boc)-OH was used, and 2 mL of acetone was added during the third 2M hydrochloric acid separation to separate the liquids, and H-Lys(Boc)-Pro- Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-9: Synthesis of H-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) Condensation The same operation as in Example Y7-2 was performed except that Fmoc-Asn(Trt)-OH was used as the amino acid to be used, and H-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf )-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-10: H-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Y2- 2) Synthesis H-Glu(OtBu)-Asn(Trt)-Lys(Boc)- Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-11: H-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu - Synthesis of OTag (Y2-2) The same operation as in Example Y7-2 was performed except that Fmoc-Tyr(tBu)-OH was used as the amino acid to be condensed, and H-Tyr(tBu)-Glu(OtBu)- Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-12: H-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile -Synthesis of Leu-OTag (Y2-2) H-Leu-Tyr(tBu)-Glu(OtBu) was prepared in the same manner as in Example Y7-2, except that Fmoc-Leu-OH was used as the amino acid to be condensed. -Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

Example Y7-13: H-PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu) -Synthesis of Ile-Leu-OTag (Y2-2) The same operation as in Example Y7-2 was performed except that Fmoc-PyroGlu-OH was used as the amino acid to be condensed, and H-PyroGlu-Leu-Tyr(tBu)- Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y2-2) was obtained as a solution.

The solvent was distilled off from the obtained organic layer under reduced pressure, 120 mL of 80% acetonitrile aqueous solution was added to the residue under ice-cooling, the obtained precipitate was filtered, dried under reduced pressure, and H-PyroGlu-Leu-Tyr ( tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Y2-2) (1. 401 g, 0.40 mmol, 33.1% yield). (The yield was calculated from the starting material compound (Y2-2) (1.21 mmol).)
ESI-MS: 3497.94 [M] ⁺

High yields of H-PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys were obtained even after 13 peptide elongation reactions consisting of Examples Y7-1 to Y7-13. (Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Y2-2) containing only one nitrogen atom such as morpholine It was confirmed that by-products can be easily removed by using a specific cyclic amine as a scavenger.

Using a small amount of this compound, a mixed solution of trifluoroacetic acid (TFA): water: triisopropylsilane (TIS) = 9.5: 2.5: 2.5 was added, and the mixture was stirred at room temperature for 3 hours. ESI-MS of H-PyroGlu-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu-OH analyzed after deprotection of chain protecting groups: 1672.77 [M+H] ⁺ was confirmed.

Example Y8: Synthesis of H-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Y3-2) Compound (Y3-2) as tag Using 0.5 g (0.428 mmol), peptide synthesis was carried out in the same manner as in Examples Y7-1 to Y7-6. It was confirmed that in liquid separation after condensation of Fmoc-Lys(Boc)-OH at the 8th residue, it took a long time to separate the organic layer and the aqueous layer during liquid separation with 2M hydrochloric acid. After leaving the solution after synthesis for one day and night, the separated organic layer was taken and subjected to mass spectrometry. The mass number of (tBu)-Ile-Leu-OTag (Y3-2) was confirmed.
ESI-MS: 2849.49 [M] ⁺

Comparative example Y3
Synthesis of H-Leu-OTag (Comparative Example Y1) Using 1.0 g (1.09 mmol) of the compound shown in Comparative Example Y1 as a tag, synthesis was carried out in the same manner as in Example Y7-1. It was confirmed that a large amount of solid precipitated in liquid separation after condensation of Fmoc-Leu-OH, making liquid separation difficult and further peptide synthesis difficult.

[Results of peptide synthesis]
Table Y4 summarizes the peptide synthesis results (number of residues) of Example Y7, Example Y8 and Comparative Example Y3, and the solubility and hydrophobicity of the benzyl compounds used. When comparing the compound (Y2-2) and compound (Y3-2), which are examples of the benzyl compound of the present invention, with the linear C ₁₈ H ₃₇ compound of Comparative Example Y1, the solubility of the benzyl compound in an organic solvent was It was confirmed that the number of peptide synthesis residues increases as the temperature increases. In addition, when comparing compound (Y2-2) and compound (Y3-2), it was confirmed that compound (Y2-2), which has moderate hydrophobicity, increased the number of peptide synthesis residues the most. bottom.

Based on these facts, it can be said that tags with high solubility in organic solvents and moderate hydrophobicity, not too high, are suitable as tags for producing long-chain peptides. As such a tag, the benzyl compounds (compounds (Y1-2), (Y2-2), (Y3-2) and (Y4-2)) according to Examples Y1 to Y4 above are used as long-chain tags in the liquid phase tagging method. Compounds (Y2-2) and (Y3-2) according to Examples Y2 and Y3 are particularly useful for peptide synthesis, and compound (Y2-2) according to Example Y2 is more useful. Confirmed that there is.

Next, an example of Embodiment 3 of the present invention described above will be given. The synthesis method will be described below using peptides having the sequences shown below as examples, but the present invention is not limited to these.

[Deprotection of Fmoc group]
The de-Fmoc scheme used in this example is shown below. The case where Y1B (also referred to as carrier (ZA)) is used as the carrier compound is described as an example, but the carrier compound that can be used in the method of the present invention is not limited to Y1B. Also, the amount of each reagent to be added is merely an example, and is not limited to this. The carrier compound Y1B is the same as the compound Y2-2.

The starting material was dissolved in a mixed solution of MTHP/DMF (8/2) so as to be 18 v/w, morpholine (20.0 equiv) and DBU (7.0 equiv) were added, and the mixture was stirred at room temperature for 1 hour. The reaction solution was transferred to a separating funnel, and 2N hydrochloric acid was added to wash and separate the liquids to obtain the de-Fmoc compound as a solution.
[Peptide synthesis method using cyclic amine scavenger]

The starting material, Fmoc-AA-OH, was dissolved in a mixture of MTHP/DMF (8/2) to a concentration of 18 v/w, and Fmoc amino acid (1.3 equiv), EDCI.HCl (1.3 equiv) and Oxyma0. 0514 g (0.1 equiv) was added and stirred at room temperature for 1 hour. Morpholine (0.4 equiv) was added and stirred at room temperature for 30 minutes. Morpholine (20.0 equiv) and DBU (7.0 equiv) were added and stirred at room temperature for 1 hour. The reaction solution was transferred to a separating funnel, and 20% saline (18 v/w) was added twice to wash and separate the solution. Further, the organic layer was washed with 2M hydrochloric acid (18v/w) × 3 times, and separated, and further washed with 0.5M sodium hydrogen carbonate aqueous solution (18v/w), separated, and the organic layer was diluted with an appropriate amount of sulfuric acid. After drying with sodium, it was filtered while washing with an appropriate amount of MTHP to obtain an amino acid condensate as a solution.

Example Z1: PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu - Synthesis of OTag (Z1-13) Example Z1-1: Synthesis of HO-Leu-OTag (Z1-1) In the same manner as in Example Y7-1, the amino acid condensate (HO-Leu-OTag (Z1- 1)) was obtained as a solution. The amino acid condensate (HO-Leu-OTag(Z1-1)) is the same as the amino acid condensate (HO-Leu-OTag(Y2-2)) synthesized in Example Y7-1.

Example Z1-2: Synthesis of HO-Ile-Leu-OTag (Z1-2) In the same manner as in Example Y7-2, an amino acid condensate (HO-Ile-Leu-OTag (Z1-2)) was prepared in solution. obtained as The amino acid condensate (HO-Ile-Leu-OTag (Z1-2)) is the same as the amino acid condensate (HO-Leu-OTag (Y2-2)) synthesized in Example Y7-2.

Example Z1-3: Synthesis of H-Tyr(tBu)-Ile-Leu-OTag (Z1-3) The same procedure as in Example Z1-2 except that Fmoc-Tyr(tBu)-OH was used as the amino acid to be condensed. After working up, H-Tyr(tBu)-Ile-Leu-OTag (Z1-3) was obtained as a solution.

Example Z1-4: Synthesis of H-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-4) The same procedure as in Example Z1-2 except that Fmoc-Pro-OH was used as the amino acid to be condensed. was carried out to obtain H-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-4) as a solution.

Example Z1-5: Synthesis of H-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-5) H-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-5 ) was obtained as a solution.

Example Z1-6: Synthesis of H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-6) In addition, the same operation as in Example Z1-2 was performed except that MTHP/DMF (8/2) was used as the reaction solvent, and H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu) -Ile-Leu-OTag (Z1-6) was obtained as a solution.

Example Z1-7: Synthesis of H-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-7) , In addition, the same operation as in Example Z1-2 was performed except that 2 mL of acetone was added during the third 2M hydrochloric acid separation to separate the liquids, and H-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr (tBu)-Ile-Leu-OTag (Z1-7) was obtained as a solution.

Example Z1-8: Synthesis of H-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Z1-8) The same procedure as in Example Z1-8 was carried out except that Lys(Boc)-OH was used, and 2 mL of acetone was added during the third 2M hydrochloric acid separation to separate the liquids, and H-Lys(Boc)-Pro- Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-8) was obtained as a solution.

Example Z1-9: Synthesis of H-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-9) Condensation The same operation as in Example Z1-2 was performed except that Fmoc-Asn(Trt)-OH was used as the amino acid to be used, and H-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf )-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-9) was obtained as a solution.

Examples Z1-10: H-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Z1- 10) Synthesis H-Glu(OtBu)-Asn(Trt)-Lys(Boc)- Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-10) was obtained as a solution.

Example Z1-11: H-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu Synthesis of -OTag (Z1-11) The same operation as in Example Z1-2 was performed except that Fmoc-Tyr(tBu)-OH was used as the amino acid to be condensed, and H-Tyr(tBu)-Glu(OtBu)- Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-11) was obtained as a solution.

Examples Z1-12: H-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile - Synthesis of Leu-OTag (Z1-12) The same operation as in Example Z1-2 was performed except that Fmoc-Leu-OH was used as the amino acid to be condensed, and H-Leu-Tyr(tBu)-Glu(OtBu) -Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-12) was obtained as a solution.

Examples Z1-13: PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile - Synthesis of Leu-OTag (Z1-13) The same operation as in Example Z1-2 was performed except that Fmoc-PyroGlu-OH was used as the amino acid to be condensed, and H-PyroGlu-Leu-Tyr(tBu)-Glu( OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z1-13) was obtained as a solution.

Example Z1-14: Deprotection of C-Terminal Carrier and Side Chain Functional Group The solvent was distilled off from the resulting organic layer under reduced pressure, and 120 mL of an 80% aqueous acetonitrile solution was added to the residue under ice-cooling to obtain The precipitate is filtered, dried under reduced pressure, and PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu )-Ile-Leu-OTag (Z1-13) (1.401 g, 0.40 mmol, 33.1% yield).
ESI-MS: 3497.94 [M] ⁺
Using a small amount of this compound, add a mixed solution of trifluoroacetic acid (TFA): water: triisopropylsilane (TIS) = 95: 2.5: 2.5, stir at room temperature for 3 hours, After deprotection of the chain protecting groups, the ESI-MS of PyroGlu-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu-OH: 1672.77 [M+H ] ⁺ was confirmed.

Example Z2: PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr with C-Terminal Support B Synthesis of (tBu)-Ile-Leu-OTag (Z2-13) The C-terminal carrier B used in Example Z2 is the following compound (Z7).

Example Z2-1: Synthesis of H-Tyr(tBu)-Ile-Leu-OTag (Z2-2) 6 mL, Fmoc-Tyr(tBu)-OH 0.789 g (1.72 mmol), EDCI.HCl 0.329 g (1.72 mmol) and Oxyma 0.0563 g (0.396 mmol) were added and stirred at room temperature for 1 hour. 45.7 μL (0.528 mmol) of morpholine was added and stirred at room temperature for 30 minutes. 2.28 mL (26.4 mmol) of morpholine and 1.38 mL (9.24 mmol) of DBU were added and stirred at room temperature for 1 hour. Under ice-cooling, the reaction solution to which 10.89 mL of 6M hydrochloric acid was added was transferred to a separating funnel, and 18 mL of 0.1M hydrochloric acid was added to wash and separate the layers. Furthermore, 18 mL of 2M hydrochloric acid was added to the organic layer to perform washing and liquid separation, and further washing and liquid separation were performed with 18 mL of 0.5M sodium hydrogencarbonate aqueous solution. After drying the organic layer with an appropriate amount of sodium sulfate, it was filtered while washing with an appropriate amount of MTHP to obtain an amino acid condensate (H-Tyr(tBu)-Ile-Leu-OTag(Z2-2)) as a solution. rice field.

Example Z2-2: Synthesis of H-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-3) The same procedure as in Example Z2-1 except that Fmoc-Pro-OH was used as the amino acid to be condensed. was carried out to obtain H-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-3) as a solution.

Example Z2-3: Synthesis of H-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-4) The procedure was carried out except that Fmoc-Arg(Pbf)-OH was used as the amino acid to be condensed. By performing the same operation as in Example Z2-1, H-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-4) was obtained as a solution.

Example Z2-4: Synthesis of H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-5) H-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-5) was obtained as a solution by performing the same operation as in Example Z2-1 except that .

Example Z2-5: Synthesis of H-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-6) The same operation as in Example Z2-1 was performed except that H-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-6) was obtained as a solution. rice field.

Example Z2-6: Synthesis of H-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Z2-7) The same operation as in Example Z2-1 was performed except that Lys(Boc)-OH was used and liquid separation was performed by the following method. The reaction solution was transferred to a separating funnel, and 18 mL of 20% saline solution was added twice to wash and separate the solution. Further, the organic layer is washed with 18 mL of 2M hydrochloric acid 3 times and separated, further washed with 18 mL of 0.5M sodium hydrogen carbonate aqueous solution, separated, and the organic layer is dried with an appropriate amount of sodium sulfate, and then added with an appropriate amount of MTHP. While washing with, filter, amino acid condensate (H-Lys (Boc)-Pro-Arg (Pbf)-Arg (Pbf)-Pro-Tyr (tBu)-Ile-Leu-OTag (Z2-7) ) was obtained as a solution.

Example Z2-7: Synthesis of H-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-8) Condensation The same operation as in Example Z2-1 was performed except that Fmoc-Asn(Trt)-OH was used as the amino acid to be used, and H-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf )-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-8) was obtained as a solution.

Example Z2-8: H-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Z2- 9) Synthesis H-Glu(OtBu)-Asn(Trt)-Lys(Boc)- Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-9) was obtained as a solution.

Example Z2-9: H-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu - Synthesis of OTag (Z2-10) The same operation as in Example Z2-6 was performed except that Fmoc-Tyr(tBu)-OH was used as the amino acid to be condensed, and H-Tyr(tBu)-Glu(OtBu)- Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-10) was obtained as a solution.

Example Z2-10: H-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile -Synthesis of Leu-OTag (Z2-11) The same operation as in Example Z2-1 was performed except that Fmoc-Leu-OH was used as the amino acid to be condensed, and H-Leu-Tyr(tBu)-Glu(OtBu) -Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-11) was obtained as a solution.

Example Z2-11: PyroGlu-Leu-Tyr(tBu)-Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile -Synthesis of Leu-OTag (Z2-12) PyroGlu-Leu-Tyr(tBu)-Glu(OtBu) was prepared in the same manner as in Example Z2-1 except that Fmoc-PyroGlu-OH was used as the amino acid to be condensed. -Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag (Z2-12) was obtained as a solution.

Under reduced pressure, the solvent was distilled off from the obtained organic layer, 45 mL of 80% aqueous acetonitrile solution was added to the residue under ice-cooling, the obtained precipitate was filtered, dried under reduced pressure, and PyroGlu-Leu-Tyr (tBu). -Glu(OtBu)-Asn(Trt)-Lys(Boc)-Pro-Arg(Pbf)-Arg(Pbf)-Pro-Tyr(tBu)-Ile-Leu-OTag(Z2-12) (1.4 g, 0.86 mmol, 54% yield). (The yield was calculated from the starting material compound (Z2-1) (1.32 mmol).)
ESI-MS: 3497.94 [M] ⁺
Using a small amount of this compound, a mixed solution of trifluoroacetic acid (TFA): water: triisopropylsilane (TIS) = 9.5: 2.5: 2.5 was added, and the mixture was stirred at room temperature for 3 hours. ESI-MS confirmed the formation of PyroGlu-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu-OH after deprotection and analysis of the chain protecting groups. ESI-MS: 1672.77 [M+H] ⁺

Example Z3: Comparison of amounts of diketopiperazine produced by various bases To an MTHP/DMF solution (8:2) of Fmoc-Tyr(tBu)-Leu-OTag (Z3-1), 5 equiv of morpholine (Z3-2) was added. After stirring for 2 hours at room temperature, quantitative analysis by HPLC was performed. The amount of diketopiperazine produced is equal to the amount of Tag-OH (Z3-8) produced simultaneously with the production of diketopiperazine. Therefore, the production rates of various compounds are Fmoc-Tyr(tBu)-Leu-OTag (Z3-1), H-Tyr(tBu)-Leu-OTag (Fmoc deprotected product, Z3-7), and diketo It was obtained by calculating the ratio of the area of each compound to the total area of the carrier compound (Z3-8) generated by piperazine formation.

Liquid chromatography (HPLC) conditions:
Column: Inert Sustain C18 (3 μm, 4.6×125 mm)
Mobile phase B: THF, mobile phase A: 0.1% trifluoroacetic acid aqueous solution Eluate: mobile phase A/mobile phase B: Measurement was carried out under the gradient conditions shown in Table Z5.

Flow rate: 1.0 mL/min
Column temperature: 40°C
Detector: UV-visible spectroscopic detector (λ=220 nm)
Comparative example Z1
Except for adding 5 equiv of diethylamine (Z3-4, described in Patent Document 9 and Non-Patent Document 4) instead of 5 equiv of morpholine, the same operation as in Example Z3 was performed and the same quantitative analysis was performed.

Comparative example Z2
Instead of 5 equiv of morpholine, 5 equiv of N-methylpiperazine (Z3-5, described in Patent Document 2)] was added, but the same operation as in Example Z3 was performed and the same quantitative analysis was performed.

[Experimental result]
As shown in Table Z2, the deprotection reaction of the Fmoc group of morpholine proceeds slower than other compounds such as the compound (N-methylpiperazine, Z3-5) described in Patent Document 2, resulting in diketo It was found that the amount of piperazine produced was small. Accordingly, we have found that the cyclic amines of the present invention can function as excellent trapping molecules in peptide synthesis.

As shown in Table Z2, morpholine was able to suppress the production rate of diketopiperazine compared to diethylamine and N-methylpiperazine. Specifically, when morpholine is used, the ratio of diketopiperazine formation to the various compounds produced is suppressed to about 60% when diethylamine is used, and about half when N-methylpiperazine is used. could be suppressed. Thus, it was confirmed that the progress of side reactions was suppressed. This is probably because unintended deprotection of the Fmoc group could be suppressed because the cyclic amine used in the present invention has low basicity.

Claims

In an organic solvent, an amino group-containing compound protected with a protective group having a fluorene skeleton at the N-terminus is brought into contact with a scavenger represented by the following formula (Z1) to obtain a compound having a fulvene skeleton derived from the protective group. obtaining a capturing body in which the by-product and the capturing agent are bound;
a step of separating the captured body obtained from the organic solvent;
including,
Peptide production method:

In the formula (Z1),
N is a nitrogen atom,
H is a hydrogen atom,
X is a divalent group represented by —CH 2 —, —O—, —S—, or —(SO 2 )—;
n 1 R 1a , n 1 R 1b , n 2 R 2a , n 2 R 2b , n 3 R 3a , and n 3 R 3b are each independently H , —OH, —OR (R is an alkyl group), —SH, —SR (R is as defined for —OR above.), —(SO 2 )H, or —(SO 2 ) A monovalent group represented by R (R is the same as that of -OR above),
R 2a or R 2b and R 3a or R 3b may be bonded to each other to form a ring together with the carbon atoms to which they are bonded,
n 1 , n 2 and n 3 are each independently 1 or 2;
m is an integer of 0 or 1;
further comprising contacting an amino group-containing compound, the N-terminus of which is protected with the protecting group, with a deprotecting agent;
The method for producing the peptide according to claim 1.
The deprotecting agent is 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1.5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,4- at least one base selected from the group consisting of diazabicyclo[2.2.2]octane (DABCO), potassium tert-butoxide, sodium tert-butoxide, triethylamine, and tributylamine;
The method for producing the peptide according to claim 2.
The step of separating the capturing body includes adding an acidic aqueous solution to the organic solvent to wash the organic solvent, separating the organic solvent into an aqueous layer and an organic layer, and then separating the separated aqueous layer. include,
3. The method for producing the peptide according to claim 1 or 2.
The scavenger represented by the formula (Z1) is at least one selected from the group consisting of morpholine, piperidine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide.
The method for producing the peptide according to claim 4.
The scavenger represented by the formula (Z1) is at least one selected from the group consisting of morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide.
3. The method for producing the peptide according to claim 1 or 2.
In an organic solvent, an amino group-containing compound protected with a protective group having a fluorene skeleton at the N-terminus is brought into contact with a scavenger represented by the following formula (Z1) to obtain a compound having a fulvene skeleton derived from the protective group. obtaining a capturing body in which the by-product and the capturing agent are bound;
a step of separating the captured body obtained from the organic solvent;
including,
Methods for removing protecting groups:

In the formula (Z1),
N is a nitrogen atom,
H is a hydrogen atom,
X is a divalent group represented by —CH 2 —, —O—, —S—, or —(SO 2 )—;
n 1 R 1a , n 1 R 1b , n 2 R 2a , n 2 R 2b , n 3 R 3a , and n 3 R 3b are each independently H , —OH, —OR (R is an alkyl group), —SH, —SR (R is as defined for —OR above.), —(SO 2 )H, or —(SO 2 ) A monovalent group represented by R (R is the same as that of -OR above),
R 2a or R 2b and R 3a or R 3b may be bonded to each other to form a ring together with the carbon atoms to which they are bonded,
n 1 , n 2 and n 3 are each independently 1 or 2;
m is an integer of 0 or 1;
A protective group removing agent having a fluorene skeleton, comprising a scavenger represented by the following formula (Z1) and a basic deprotecting agent:

In the formula (Z1),
N is a nitrogen atom,
H is a hydrogen atom,
X is a divalent group represented by —CH 2 —, —O—, —S—, or —(SO 2 )—;
n 1 R 1a , n 1 R 1b , n 2 R 2a , n 2 R 2b , n 3 R 3a , and n 3 R 3b are each independently H , —OH, —OR (R is an alkyl group), —SH, —SR (R is as defined for —OR above.), —(SO 2 )H, or —(SO 2 ) A monovalent group represented by R (R is the same as that of -OR above),
R 2a or R 2b and R 3a or R 3b may be bonded to each other to form a ring together with the carbon atoms to which they are bonded,
n 1 , n 2 and n 3 are each independently 1 or 2;
m is an integer of 0 or 1;
The scavenger is at least one selected from the group consisting of morpholine, 3-hydroxypiperidine, 4-hydroxypiperidine, thiomorpholine, and thiomorpholine dioxide.
The remover according to claim 8.
The deprotecting agent includes 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, 1,4-diazabicyclo[2.2. 2] at least one base selected from the group consisting of octane, potassium tert-butoxide, sodium tert-butoxide, triethylamine, and tributylamine;
The remover according to claim 8 or 9.
The following formula (Y1):

[In the formula,
m Q's each represent an oxygen atom,
m R 1 are each independently represented by the following formula (YA):

(In the formula,
* indicates the binding position,
R 1a , R 1b , R 1c , R 1d and R 1e each independently represent a hydrogen atom or an alkyl group,
n 1 represents an integer of 0 to 6, and when n 1 is 1 or more, the repeating unit shown in parentheses to which n 1 is attached is an alkylene group,
n 2 represents an integer of 0 or more and 6 or less, and when n 2 is 1 or more, the repeating unit shown in parentheses to which n 2 is attached is an alkylene group,
However, at least two or more of R 1a , R 1b , R 1c and R 1d are hydrogen atoms. )
is a group represented by
k R 2 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom;
X represents a hydroxyl group,
m represents an integer of 2 or 3,
k represents an integer of 0 or more (5-m) or less,
At least one of m [QR 1 ] is substituted at the meta position with respect to the substituent containing X. ]
Benzyl compound (Y1) represented by.
total carbon number is 40 or more and 60 or less,
12. The benzyl compound (Y1) according to claim 11.
The m R 1s are each independently an organic group having one branched chain,
The following formula (YA'):

(In the formula,
* indicates the binding position,
R 1f is a linear alkyl group having 4 to 12 carbon atoms,
R 1g is a linear alkyl group having 6 to 14 carbon atoms. ) is a group represented by
12. The benzyl compound (Y1) according to claim 11.
The R 1f is a linear alkyl group having 4 to 10 carbon atoms,
The R 1g is a linear alkyl group having 6 to 12 carbon atoms,
14. The benzyl compound (Y1) according to claim 13.
A dissolving step of dissolving the benzyl compound according to any one of claims 11 to 14 in a soluble solvent;
Next, a condensation reaction step of condensing the dissolved benzyl compound and an amino acid whose N-terminus is protected by an N-terminal protecting group to produce a first condensate;
Then, a first base is added to the soluble solvent containing the first condensate to scavenge the amino acid active ester, the first base and the second base are added to the soluble solvent, and the second base is added to the soluble solvent. deprotecting the N-terminal protecting group from the condensate of 1 and scavenging by-products derived from the N-terminal protecting group with the first base;
Next, an acidic aqueous solution is added to the soluble solvent containing the captured bodies captured in the scavenging step to wash the solvent, and the aqueous layer and the organic layer are separated to remove the captured bodies and unnecessary substances to the aqueous layer. , a liquid separation step of obtaining a second condensate in which the N-terminal protecting group is deprotected from the first condensate in the organic layer;
A method for producing a peptide, comprising:
In the condensation reaction step, a 2n-th condensate comprising an amino acid whose N-terminus is unprotected and an amino acid whose C-terminus is protected with the benzyl compound, and which has n residues, condensing the n-th N-terminally protected amino acid to form the (2n+1)-th condensate;
the step of scavenging comprises performing deprotection of the N-terminal protecting group from the (2n+1)th condensate;
The liquid separation step includes a step of obtaining a (2n+2)th condensate in which the N-terminal protecting group is deprotected from the (2n+1)th condensate in the organic layer,
The n is a natural number of 2 or more,
A method for producing the peptide according to claim 15 .
wherein said n is 5 or more;
A method for producing the peptide according to claim 16 .
The liquid separation step further includes adding a ketone-based liquid separation promoting solvent to the soluble solvent.
A method for producing the peptide according to claim 15 .
The following formula (X1):

[In the formula,
m Q 1 and Q 2 are each an oxygen atom,
m R 1 are each independently an alkylene group,
m R 2 are each independently an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted aryl group,
k R 3 are each independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom,
X is a hydroxyl group,
m is an integer of 2 or 3,
k represents an integer from 0 to (5-m). ]
Benzyl compound (X1) represented by.
The m R 1s are alkylene groups having 2 to 16 carbon atoms,
The benzyl compound (X1) according to claim 19.
The m R 2 is an aryl group having a substituent containing a halogen atom,
The benzyl compound (X1) according to claim 19 or 20.
The m R 2 are alkyl groups having 5 to 28 carbon atoms,
The benzyl compound (X1) according to claim 19 or 20.
The m R 2 are linear alkyl groups or alkyl groups having a total of 1 or 2 branched chains, and are represented by the following formula (XA):

(In the formula,
* indicates the binding position,
R 2a , R 2b , R 2c , R 2d and R 2e each independently represent a hydrogen atom or an alkyl group,
n 1 represents an integer of 0 or more and 16 or less,
n2 represents an integer of 0 or more and 16 or less.
However, at least two or more of R 2a , R 2b , R 2c and R 2d are hydrogen atoms. ) is a group represented by
23. The benzyl compound (X1) according to claim 22.