JPH06228099A - Production of thiol-protecting derivative - Google Patents

Abstract

PURPOSE:To obtain the subject derivative protected with 3-nitro-2-pyridyl sulfide in high yield by reacting a benzyl 3-nitro-2-pyridyl sulfide with sulfuryl chloride and reacting the reaction product with a SH protecting thiol compound. CONSTITUTION:2-Chloro-3-nitropyridine and 4-methoxyphenylmethanethiol are heated under reflux in the presence of triethylamine in methanol for 4 hours to give a benzyl 3-nitro-2-pyridyl sulfide of formula I (R is H, alkyl or alkoxy), which is dissolved in dichloromethane and reacted with sulfuryl chloride at 0 deg.C at room temperature for 20 minutes to give 3-nitro-2-pyridinesulfenyl chloride of formula II. 3-Nitro-2-pyridinesulfenyl chloride is not isolated and reacted with a thiol compound containing a SH-protecting group of the formula A-S(X) (A is protected amino residue or protected peptide; X is thiol-protecting group) to give a thiol-protecting derivative protected with 3-nitro-2-pyridinesulfenyl group of formula III.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is known as a protecting group for cysteine or thiol group, and is a 3-nitro-2-pyridinesulfenyl group having a property of selectively leaving to form an S-S bond in peptide synthesis and the like. By reacting a compound protected with an (Npys) group with a thiol compound protected with an SH group without isolating 3-nitro-2-pyridinesulfenyl chloride (Npys-Cl), high purity, It is intended to provide a method of synthesizing in high yield and easily.

[0002]

2. Description of the Related Art The Npys group is a new thiol protecting group developed by Matsueda et al. And has the ability to form an S--S bond by reacting with a free SH group [Chem. Let
t. , 737 (1981), Int. J. Peptid
e Protein Res. , 28 , 107 (198
6) Description], and introduced using Npys-Cl. Conventionally, Npys-Cl was synthesized by Matsueda et al. By the reaction of bis (3-nitro-2-pyridyl) disulfide with chlorine [Chem. Lett. , 951 (1978)
Description]. The compound protected by the Npys group is
Although it is synthesized using s-Cl, its use is limited because Npys-Cl itself is unstable and expensive. Further, an amino acid having an SH group protected by an Npys group is commercially available, but it is expensive.

[0003]

In the conventional synthesis method,
Since the raw material Npys-Cl is unstable and expensive, there is a problem in that it is difficult to obtain an inexpensive amino acid having an SH group protected by an Npys group.

[0004]

[Means for Solving the Problems] The inventors of the present invention used benzyl 3-nitro-2-pyridyl sulfide, which has good solubility, as a raw material, and reacted with sulfuryl chloride to produce Np
By synthesizing ys-Cl with high purity and high yield, and reacting it with a thiol compound having a protected SH group without isolation, ys-Cl is protected with the target Npys group at high yield and at low cost. As a result of discovering that the above compound can be synthesized and conducting further detailed studies, the present invention has been completed.

More specifically, the present invention will be described in more detail. Benzyl 3-nitro-2-pyridyl sulfides represented by the following general formula (II) and sulfuryl chloride are treated with an inert gas (eg, helium, argon, etc.) atmosphere. under,
After reacting for several tens of minutes at 0 ° C or lower, N represented by the following formula (III)
Pys-Cl was synthesized, and the system was sufficiently replaced with an inert gas without isolation, and the following general formula (IV)
A method of synthesizing a target compound protected by an Npys group represented by the following general formula (I) with high purity and high yield by adding a solution of a thiol compound represented by is there.

[0006]

[Chemical 2]

In the formula, R represents a hydrogen atom, an alkyl group or an alkoxy group. A represents a protected amino acid residue or a peptide containing a protected amino acid residue, and X represents a thiol protecting group used for peptide synthesis and the like.

In the reaction formula shown in Chemical Formula 2, R is a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group;
Examples thereof include alkoxy groups such as methoxy group and ethoxy group. A includes protected amino acid residues represented by cysteine, penicylamine and the like; peptides containing protected amino acid residues represented by cysteine, penicylamine and the like.
X represents a thiol protecting group such as a methoxybenzyl (MBzl) group. Even when there are a plurality of S (X) groups, a compound protected with an Npys group can be synthesized by the same method. An example of the method for producing the compound protected by the Npys group of the present invention will be described below.

4-methoxybenzyl 3-nitro-2-
Pyridyl sulfide was dissolved in dichloromethane, and sulfuryl chloride was added at 0 ° C. under an argon gas atmosphere to react to synthesize Npys-Cl. After the system was sufficiently replaced with argon gas, it was protected with 4-methoxybenzyl group. By adding a solution of a thiol compound and reacting it, a target compound protected by an Npys group can be synthesized.
The reaction is carried out in dichloromethane under an inert gas atmosphere at room temperature for several tens of minutes, the solvent is removed, and the residue is purified by column chromatography to obtain the desired product in high yield and high purity.

[0010]

INDUSTRIAL APPLICABILITY According to the present invention, benzyl 3-nitro-2-pyridyl sulfides and sulfuryl chloride are allowed to act, and without isolation, a thiol compound having a protected SH group is added to this system to react with each other. The target Npy
It is a novel and efficient production method capable of synthesizing a compound protected with an s group in high yield and high purity.

[0011]

EXAMPLES Examples will be shown below for illustrating the present invention in more detail, but they do not limit the present invention.

Example 1 (1) Synthesis of 4-methoxybenzyl 3-nitro-2-pyridyl sulfide 2-chloro-3-nitropyridine 2.18 g (13.8)
Mmol) and 4-methoxyphenylmethanethiol 2.
5 ml (21.3 mmol), triethylamine 2.5
After dissolving ml (21.3 mmol) in 10 ml of methanol and heating under reflux for 4 hours, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography using chloroform as an eluent to obtain 3.54 g of the desired product ( Yield 9
3%) was obtained. Melting point 89.2 to 90.0 ° C Elemental analysis CHNS Calculated value 56.51 4.38 10.14 11.60 Measured value 56.80 4.31 10.15 11.44

(2) Synthesis of compound protected with Npys group Synthesis of Fmoc-Cys (Npys) -OH 4-methoxybenzyl 3-nitro-obtained in (1)
103 mg (0.37 mmol) of 2-pyridyl sulfide was dissolved in 0.5 ml of dichloromethane, and sulfuryl chloride 0.03 ml was added at 0 ° C under an argon gas atmosphere.
(0.48 mmol) was added, and the mixture was stirred at room temperature for 20 minutes. After the system was sufficiently replaced with argon gas, Fmoc-Cys (MBzl) -OH (Fmoc was 9-
Represents a fluorenylmethyloxycarbonyl group, Cys
Represents a cysteine residue) was added to a solution of 116 mg (0.25 mmol) in 12.5 ml of dichloromethane, the mixture was stirred for 30 minutes, and the solvent was distilled off. An ethyl acetate solution was added to the obtained residue to dissolve it, which was washed with 5% citric acid aqueous solution, water, and saturated saline solution in this order, dried with a desiccant, and then the solvent was distilled off. Chloroform: methanol = 22:
Purification by column chromatography using 5 as a developing solvent gave 107 mg (yield 86%) of the desired product. Melting point 1
70.0 to 171.0 ° C [α] _D ²⁷ -74.1 °
(Cl, DMF) ¹ H-NMR (CDCl ₃ ) δ = 3.1-3.3 (2H, d, β-CH ₂ ), 4.2
(1H, t, CH), 4.3-4.5 (3H, m, α-
_{CH, CH 2), 6.2-6.4 (} 1H, br, N
H), 7.1-7.9 (10H, m, Ar-H), 8.
5 (1H, d), 9.9-10.2 (1H, br, CO
OH)

Boc-Cys (MBzl) -OH was prepared in the same manner as in the synthesis of Boc-Cys (Npys) -OH.
(Boc represents a t-butoxycarbonyl group) 341 m
324 mg of the target product was reacted with g (1.0 mmol).
(Yield 86%) was obtained. Melting point 153.0-158.0
° C [α] _D ²⁶ -85.6 ° (cl, CH ₃ OH), ¹ H-NMR (CDCl ₃ ) δ = 1.4 (9H, s, ^t Bu), 3.2-3.4 ( Two
H, d, β-CH ₂ ), 4.2-4.3 (1H, br,
α-CH), 6.2-6.3 (1H, br, NH),
7.5 (1H, dd), 8.5 (1H, dd), 8.9
(1H, dd), 9.0-9.2 (1H, br, COO
H)

Boc-D-Pen (Npys) -OH
Synthesis of 4-methoxybenzyl 3-nitro-obtained in (1)
899 mg (3.28 mmol) of 2-pyridyl sulfide was dissolved in 4.3 ml of dichloromethane, and 0.26 ml of sulfuryl chloride was added at 0 ° C under an argon gas atmosphere.
(4.20 mmol) was added, and the mixture was stirred at room temperature for 20 minutes. After thoroughly replacing the system with argon gas, Boc-D-Pen (MBzl) -OH (D-Pen represents a D-penicylamine residue) 807 mg (2.19) was added to this solution.
Was added to 110 ml of dichloromethane, the mixture was stirred for 30 minutes, and then the solvent was distilled off. An ethyl acetate solution was added to the obtained residue to dissolve it, which was washed with a 5% citric acid aqueous solution and a saturated saline solution in this order, dried with a desiccant, and then the solvent was distilled off. Chloroform: methanol = 22:
Purification by column chromatography using 5 as a developing solvent gave 621 mg of the desired product (yield 70%). Melting point 1
55.5 to 158.5 ° C [α] _D ²⁵ −29.0 °
_{(Cl, C 2 H 5 OH} ) 1 H-NMR (CDCl 3) δ = 1.2-1.6 (15H, m, t Bu, CH 3),
4.1-4.2 (1H, br, α-CH), 6.2-
6.3 (1H, br, NH), 7.45 (1H, d
d), 8.6 (1H, dd), 8.9 (1H, dd),
9.9-10.2 (1H, br, COOH) Elemental analysis CHN Calculated value 44.65 5.25 10.41 Measured value 44.51 5.19 10.41

Fmoc-D-Pen (Npys) -O
Synthesis of H Fmoc-D-Pen (MBzl) -OH was reacted in the same manner as above to obtain 413 mg of the desired product (yield 78%).
Got Melting point 113.0-116.0 ° C [α] _D ²⁷ -13.6 ° (cl, DMF) ¹ H-NMR (CDCl ₃ ) δ = 1.4 (6H, d, CH ₃ ), 4.2 (1H, t,
CH), 4.3-4.5 (3H, m, α-H, C
_{H 2), 6.2-6.4 (1H,} br, NH), 7.1
-7.9 (10H, m, Ar-H), 8.5 (1H,
d), 8.9 (1H, dd), 9.8-10.0 (1
H, br, COOH)

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[Procedure amendment]

[Submission date] February 26, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

(2) Synthesis of compound protected with Npys group Synthesis of Fmoc-Cys (Npys) -OH 4-methoxybenzyl 3-nitro-obtained in (1)
103 mg (0.37 mmol) of 2-pyridyl sulfide was dissolved in 0.5 ml of dichloromethane, and sulfuryl chloride 0.03 ml was added at 0 ° C under an argon gas atmosphere.
(0.48 mmol) was added, and the mixture was stirred at room temperature for 20 minutes. After the system was sufficiently replaced with argon gas, Fmoc-Cys (MBzl) -OH (Fmoc was 9-
Represents a fluorenylmethyloxycarbonyl group, Cys
Represents a cysteine residue) was added to a solution of 116 mg (0.25 mmol) in 12.5 ml of dichloromethane, the mixture was stirred for 30 minutes, and the solvent was distilled off. An ethyl acetate solution was added to the obtained residue to dissolve it, and the solution was washed with 5% citric acid aqueous solution and water / saturated saline solution (1: 1) in this order, dried with a desiccant, and then the solvent was distilled off, followed by chloroform. : Methanol = 22: 5 was used as a developing solvent for purification to obtain 107 mg (yield 86%) of the desired product.
Mp from 170.0 to 171.0 ° C [α] _D ²⁷ -7
4.1 ° (cl, DMF) ¹ H-NMR (CDCl ₃ ) δ = 3.1-3.3 (2H, d, β-CH ₂ ), 4.2
(1H, t, CH), 4.3-4.5 (3H, m, α-
_{CH, CH 2), 6.2-6.4 (} 1H, br, N
H), 7.1-7.9 (10H, m, Ar-H), 8.
5 (1H, d), 8.9 (1H, d), 9.9-10.
2 (1H, br, COOH)

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Boc-D-Pen (Npys) -OH
Synthesis of 4-methoxybenzyl 3-nitro-obtained in (1)
899 mg (3.28 mmol) of 2-pyridyl sulfide was dissolved in 4.3 ml of dichloromethane, and 0.26 ml of sulfuryl chloride was added at 0 ° C under an argon gas atmosphere.
(4.20 mmol) was added, and the mixture was stirred at room temperature for 20 minutes. After thoroughly replacing the system with argon gas, Boc-D-Pen (MBzl) -OH (D-Pen represents a D-penicylamine residue) 807 mg (2.19) was added to this solution.
Was added to 110 ml of dichloromethane, the mixture was stirred for 30 minutes, and then the solvent was distilled off. An ethyl acetate solution was added to the obtained residue to dissolve it, and the solution was washed with 5% citric acid aqueous solution and water / saturated saline solution (1: 1) in this order, dried with a desiccant, and then the solvent was distilled off, followed by chloroform. Purification by column chromatography using methanol: 22: 5 as a developing solvent gave 621 mg of the desired product (yield 70%). Melting point 155.5 to 158.5 ° C. [α] _D ²⁵ −
29.0 ° (cl, C ₂ H ₅ OH) ¹ H-NMR (CDCl ₃ ) δ = 1.2-1.6 (15H, m, ^t Bu, CH ₃ ),
4.1-4.2 (1H, br, α-CH), 6.2-
6.3 (1H, br, NH), 7.45 (1H, d
d), 8.6 (1H, dd), 8.9 (1H, dd),
9.9-10.2 (1H, br, COOH) Elemental analysis CHN Calculated value 44.65 5.25 10.41 Measured value 44.51 5.19 10.41

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Fmoc-D-Pen (Npys) -O
Synthesis of H Fmoc-D-Pen (MBzl) -OH was reacted in the same manner as above to obtain 413 mg of the desired product (yield 78%).
Got Melting point 113.0-116.0 ° C. [α] _D ²⁷ 13.6 ° (cl, DMF) ¹ H-NMR (CDCl ₃ ) δ = 1.4 (6H, d, CH ₃ ), 4.2 ( 1H, t,
CH), 4.3-4.5 (3H, m, α-H, C
_{H 2), 6.2-6.4 (1H,} br, NH), 7.1
-7.9 (10H, m, Ar-H), 8.5 (1H,
d), 8.9 (1H, d) , 9.8-10.0 (1H,
br, COOH)

Claims (1)

[Claims] 1. A benzyl compound represented by the following general formula (II):
3-nitro-2-pyridyl sulfides represented by the following formula (III) obtained by reacting sulfuryl chloride
Nitro-2-pyridinesulfenyl chloride is reacted with a thiol compound having a protected SH group represented by the following general formula (IV) without isolation, and a compound represented by the following general formula (I) is represented by 3- A method for producing a thiol-protected derivative protected with a nitro-2-pyridinesulfenyl group. [Chemical 1] In the formula, R represents a hydrogen atom, an alkyl group or an alkoxy group. A represents a protected amino acid residue or a peptide containing a protected amino acid residue. X represents a thiol protecting group used for peptide synthesis and the like.