WO1997028117A1

WO1997028117A1 - Novel processes for producing l-glutamine and novel intermediates for synthesis thereof

Info

Publication number: WO1997028117A1
Application number: PCT/JP1997/000219
Authority: WO
Inventors: Yukio Soeda; Teruo Kutsuma; Kiyoshi Nakagawa
Original assignee: Sun A Pharm Co., Ltd.
Priority date: 1996-02-02
Filing date: 1997-01-30
Publication date: 1997-08-07

Abstract

A process for industrially producing L-glutamine of a high purity which comprises η-amidating the L-isomer of a compound represented by general formula (Chemical formula (1)) or its salts, (wherein R1 represents hydrogen or lower alkyl; and R2 represents lower alkyl or lower alkyloxy) and, after the completion of the reaction, eliminating the protecting group therefrom; and novel intermediates therefor. A process for producing L-glutamine which comprises preparing a compound of the above general formula (Chemical formula (1)) from L-glutamic acid or its ester followed b y η-amidation and the elimination of the protecting group. Compounds of the general formula (Chemical formula (1)) wherein R 1 is lower alkyl or their salts.

Description

Specification

Novel production method of L-glutamine and novel synthetic intermediate thereof

Technical field

The present invention relates to a novel synthetic production method of L-glutamine, which is used in large quantities as pharmaceuticals and various pharmaceutical intermediates, and a new industrial intermediate material used for synthetic production. Background art

Extraction, fermentation, and synthesis methods are known as methods for producing L-glutamine, but those produced industrially are by the fermentation method. According to the fermentation method, L-glutamine itself is chemically unstable, so it is easily hydrolyzed to L-glutamic acid with acid, alkali or hot water, and is closed to form L-pyridone carboxylic acid. Because of the acidity, it is very difficult to isolate and purify L-glutamine from fermentation broth. Therefore, the production cost is very high.

For this reason, synthetic methods for producing L-glutamine have been studied for a long time. As can be seen in Japanese Patent Publications Nos. 40-620, No. 46-116, and No. 48-149, these methods are all L-glutamine. In this method, L-daltamine is produced by amidating an acid r ester in the presence of carbon disulfide. However, as is well known, carbon disulfide is highly toxic, volatile and easily flammable, and steam is heavier than air and stays in low places to create an explosive mixed gas. Charges and ignites or explodes due to discharge sparks. For this reason, this method has not yet been industrialized. An object of the present invention is to use a synthesis method instead of a fermentation method in order to produce high-purity L-glutamine at low cost, and not to use dangerous carbon disulfide, which is a barrier to industrialization. Is to provide.

Disclosure of the invention

In summary, the first invention of the present invention relates to a method for producing L-glutamine or a salt thereof, and has the following general formula (Formula 1):

R'〇COCH ₂ CH ₂ CHCO〇H

I

N

/ \

CH ₃ — CH

II

CH 0

\

C

I

R ²

(Wherein, R ¹ represents hydrogen or a lower alkyl group, and R ² represents a lower alkyl group or a lower alkyloxy group). It is characterized in that the protecting group is removed after the reaction.

The second invention of the present invention relates to a method for producing another L-glutamine or a salt thereof, and comprises the following general formula (Formula 2):

R ¹ OCOCH ₂ CH ₂ CHCOOH

NH ₂

(Wherein, R ¹ represents hydrogen or a lower alkyl group) to a compound represented by the general formula: CH ₃ COCH ₂ CO—R ² (wherein R ² represents a lower alkyl group or A lower alkyloxy group) to protect the amino group, followed by selective amidation at the r-position, and removal of the protecting group after the reaction. A third invention of the present invention is a compound represented by the following general formula (Formula 3):

R ³ OCOCH ₂ CH ₂ CHCOOH

I

N

/ \

CH ₃ -CH

II:

CH O

\

C

I

R ²

Wherein R ³ represents a lower alkyl group and R ² represents a lower alkyl group or a lower alkyloxy group, or a salt thereof.

As a result of various studies, the present inventors have completed the present invention by using alkyl acetate or acetylacetone instead of carbon disulfide.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described specifically.

First, the selective amidation at the r-position in the first invention and the second invention of the present invention is carried out by isolating the isolated compound represented by the general formula (I) 1 or a salt thereof, or Compounds of the formula (1) which are formed by the reaction as in the second invention and which contain L or a salt thereof include methanol, ethanol, tetrahydrofuran, methylene chloride, and acetone. An amidating agent (preferably, ammonia gas, liquid ammonia or aqueous ammonia) is directly reacted in an organic solvent such as tolyl, or once reacted with L-amino acid in the compound represented by the general formula (Chemical Formula 1). Glutamate can be carried out by activating the carboxyl group at the 1-position and then reacting it. When the above-mentioned activation is carried out in advance, an acid halogenating agent (preferably thionyl chloride) is used. And then reacting with an amidating agent (preferably ammonia gas or liquid ammonia).

After the reaction, the protecting group may be removed by a conventional method, but is preferably removed by hydrolysis with an acid (preferably diacid).

As described above, according to the method of the present invention, r-number one amidation can be selectively performed without using carbon disulfide as in the prior art.

In the first invention of the present invention, among the compounds represented by the general formula (Chemical Formula 1) as the raw materials, compounds in which the group R ¹ is hydrogen are described, for example, in Japanese Patent Publication No. Sho. Known compounds. As described in the above-mentioned public notice, the substance can be added to an alkali metal salt of glutamic acid in an organic solvent such as isopropyl alcohol, ether, chloroform, dioxane, benzene, toluene, or the like. It can be obtained by reacting the corresponding acetate acetate or 0-diketon under mild conditions of from normal temperature to heating.

Among the compounds represented by the general formula (Chemical Formula 1), the compound in which the group R ¹ is a lower alkyl group, as described above, a compound targeted by the third invention of the present invention, 3) This is a novel compound. Is an example of the lower alkyl group represented by general formula (3) group in the compound represented by R ² and groups R ^3, Number 1-6 alkyl group atoms, such as methyl, Echiru, n- propyl, i-propyl, n-butyl, i-butyl, t-butyl, pentyl and hexyl groups.

The compound represented by the general formula (Formula 3) can be produced, for example, according to the following method.

Specifically, glutamate or a functional derivative thereof (eg, an alkali metal salt such as a sodium salt, an acid halide, an acid anhydride, an ester, or the like) is added to R ³ —React an alcohol corresponding to 官能 H, or a corresponding functional derivative thereof (eg, an alcoholate such as a sodium salt, an alkali metal halide, an ester, etc.) by a conventional esterification method, and then react with a general formula: CH ₃ COCH the § Seto acid alkyl esters or Asechiruase tons compound represented by ₂ CO- R ² may be reacted.

For example, L-glutamic acid or sodium L-glutamate is converted to an alcohol represented by R ^{3 —}又は H (preferably methanol or e) in the presence of an acid (preferably dimethyl sulfate, sulfuric acid, or hydrochloric acid) or thionyl chloride. (Tanol) in an organic solvent. Alternatively, an alkyl halide (preferably methyl iodide) is reacted in an organic solvent such as methylene chloride or acetonitrile in the presence of a base (preferably caustic soda) to form L-glutamic acid. — Produce alkyl esters.

Next, a base (preferably caustic soda or sodium methylate) is added, followed by reaction with acetoacetate alkyl ester or acetylacetone.

Further, the compound represented by the general formula (Chemical Formula 3) is prepared by suspending or dissolving glutamic acid in an organic solvent such as alcohol by changing the order of the reaction from the above-described method, and then adding sodium hydroxide or sodium methacrylate. Then, L-glutamic acid salt of sodium sodium is added to the mixture to react with an alkyl acetate or acetyl acetate to react N- (1-acyl-substituted propene-2-yl) -1-L-. Glutamic acid [ie, some known compounds of the general formula (Chemical Formula 1) wherein the group R ¹ is hydrogen] is produced, and then an esterifying agent (eg, thionyl chloride mouth light, methyl iodide, dimethyl sulfate, sulfuric acid) , Hydrochloric acid, etc.) and reacting by a conventional esterification method. In the second invention of the present invention, L-glutamic acid, or a salt thereof, which is used as one of the starting materials, is sodium glutamate chemically. It is a stable substance produced by the fermentation method and has been used in large quantities since ancient times as a raw material for foods, pharmaceuticals and various pharmaceuticals. L-glutamic acid アルキル -alkyl ester is also a known substance, as shown in Japanese Patent Publication Nos. 40-6206, 46-11641 and 48-1049, and is known to be an acid catalyst (preferably). Can be easily produced by reacting lower alcohols in the presence of dimethyl sulfate, sulfuric acid and hydrochloric acid.

In addition, L-integration of the compound represented by the general formula (Ig 1) can be carried out by an asymmetric synthesis method using a conventional method, an optical resolution method from a reaction product, or L-glutamic acid or a functional derivative thereof. It can be easily obtained by the method used. Further, salt formation in the raw material, the intermediate or the target substance can be carried out by a conventional method.

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1

L-glutamic acid 5-methyl ester 5.0 g in 50 ml of methanol

(31 mM) was suspended. Under stirring, 50 ml of a methanol solution containing 1.24 g (31 mM) of caustic soda was added dropwise, and the solution became clear about 20 minutes after the start of the dropwise addition. Next, a 25 ml solution of methanol in which 3.8 g of methyl acetate was dissolved was added dropwise, and after the completion of the addition, the mixture was refluxed for 30 minutes. The mixture was allowed to cool to room temperature to obtain a solution of N- (1-methoxycarbonylpropene-1-yl) -1-L-glutamate sodium 5-methyl ester. A part of the reaction solution was taken out and its production was confirmed by the following analysis. Next, 500 ml of 25% aqueous ammonia was added to the reaction solution, and the mixture was stirred for 2 hours. The solution was concentrated under reduced pressure at a bath temperature of 50 ° C. or less until the amount became 20 g, to obtain a concentrated oil of N— (1-methoxycarbonylpropene-2-yl) -1-L-glutamine sodium. A part of the concentrated oil was taken out and its production was confirmed by the following analysis. Then, 17 ml of methanol, 8 ml of acetic acid (14 Om) and 8 ml of water were sequentially added to the concentrated oil. The pH of the solution was 4.2, and a small amount of L-glutamine seed crystal was added under ice cooling, and crystals precipitated from the solution. The crystals were collected by filtration, washed with methanol, and the obtained crystals were dissolved in 4 Om 1 of water, adjusted to pH 5.5 with aqueous ammonia, and filtered. The solution was concentrated under reduced pressure at a bath temperature of 40 ° C. or lower until the volume became about half the volume, 22 ml of methanol was slowly added to the obtained solution, and the mixture was stirred overnight, and the crystals were collected by filtration. The obtained crystals were washed with methanol and then with ether, and dried under reduced pressure at 40 ° C or lower. The yield of L-glutamine was 2.94 g.

Melting point: 185 ° C (decomposition)

Specific rotation: [na] D ²⁰ 10 Omm, C = 2% (2N-HC 1) 32.2 ° Elemental analysis Theoretical value C: 41.09% H: 6.90% N: 19.17% Analytical value C: 41.01% H: 6.80% N: 1 8.96% N- (1-Methoxycarbonylpropene-1-yl) _L-Glutamic acid sodium 5-methyl ester analysis

The reaction solution taken out was dried under reduced pressure, crystallized from ether, and subjected to NMR measurement.

NMR (CD ₃ 〇D. C5)

1.92 C3H.s, = C (ΝΗ) -Me], 2.10 (2Η, m, CH ₂ -CH ₂ -CH), 2.30 (2H, t, J = 8.55, OC-

CH ₂ -CH ₂ ), 3.56 (3 H, s, C-Me). 3.70 (3 H, s.COO-Me), 3.98 (1 H.m.CH2-CH-NH (COONa)), 4.41 (1 H. s, = CH— C〇Me)

N— (1-Methoxycarbonylpropene-1-yl) -1-: L-Glutamin sodium

The concentrated oil taken out is dried under reduced pressure, crystallized from ether, NMR measurements were taken.

NMR (CDaOD, d)

1.92 [3 H, s. = C (NH) -Me, 2.10 (2 H, m, CH2-CH -CH), 2.29 (2H, t, J = 7.93, OC-C. H ^-CH2) , 3.56 (3H, s.C -OMe), 3.97 1 H.t.J = 6.1 1, CH ₂ -CH-NH (COON a)], 4.41 (1 H, s, -CH-COMe)

Example 2

2.0 g of L-glutamic acid 5-methyl ester was suspended in 10 ml of methanol. Under stirring, 2.0 g of a 28% sodium methoxide-methanol solution was added dropwise, and after the addition, the insoluble material was removed by filtration, 30 ml of isopropyl alcohol was added, and then ethyl acetate 1.9 was added. The mixture was added dropwise, and heated under reflux for 12 hours. The solution was allowed to cool to room temperature to obtain a solution of N- (1-ethoxycarbonylpropene-1-yl) -l-l-sodium sodium daltamate 5-methylester. A part of the reaction solution was taken out and its production was confirmed by the following analysis. Next, the reaction solution was cooled to 0 ° C., and ammonia gas was blown for 2 hours. After the completion of the reaction, the mixture was concentrated under reduced pressure to obtain a concentrated N- (1-ethoxyquinpropene-1-yl) -L-glutamine sodium enriched oil. A part of the concentrated oil was taken out and its production was confirmed by the following analysis. Then, 7 m of methanol was added to the concentrated oil, and 3 ml of acetic acid and 3 ml of water were sequentially added. Under ice cooling, a small amount of L-glutamine seed crystal was added, and crystals precipitated from the solution. The crystals were collected by filtration, washed with methanol, and the obtained crystals were dissolved in 16 ml of water, adjusted to pH 5.5 with aqueous ammonia, and filtered. Bath temperature 4 (Concentrate under reduced pressure to about half the volume below TC, slowly add 9 ml of methanol to the concentrated solution, stir overnight, and collect the crystals by filtration. The obtained crystals are washed with methanol and then with ether. After that, decrease below 40 ° C Pressure dried. The yield of L-daltamine was 1.17.

Melting point: 186 ° C (decomposition)

Specific rotation: [a] _D ² . 100mm, C = 2% (2N-HC 1) 32.3 Analysis of N- (1-ethoxycarbonylpropene-1-yl) -1-L-sodium glutamate 5-methyl ester

NMR (CD ₃ OD.δ)

1.15 (3Η, t, J = 7.32, OCH2-CH3) 1.90 (3 Η.s, = C (NH) -Me), 2.10 (2H, m, CH2 CH2 one CH), 3.65 (3H.s, COO — Me), 3.90 [1 H, t. J = 6.72, CHz-CH-NH (COONa)], 4.03

Analysis of N- (1-ethoxycarbonylpropene-1-yl) -1-L-glutamine sodium formation

The concentrated oil taken out was dried under reduced pressure, crystallized from ether, and subjected to NMR measurement.

NMR (CDaOD, <5)

1.21 (3H.t. J = 7.33, 100 CH ₂ — Cii ^), 1.92 [3H.s. = C (NH) -Me], 2.04 (2H, m, CH _2-

-. CH), 2.35 (2H , t, J = 7.94, H2NCOCH2), 3.99 C 1 H, t, J = 6.72, CH 2 -CH ~ NH (COONa) ] 4.03 (2H q, J = 7.33 , -OCHaCHa ), 4.40 (1 H, s. = CH-CO)

Example 3

5.0 g of L-glutamic acid 5-methyl ester in 50 ml of methanol Suspended. Under stirring, 5 Oml of a methanol solution containing 1.24 g of caustic soda was added dropwise, and the solution became clear about 20 minutes after the start of the dropwise addition. Next, a 25 ml solution of methanol in which 3.8 g of acetylacetyl was dissolved was added dropwise, and after the completion of the addition, the mixture was refluxed for 30 minutes. After cooling to room temperature, a solution of N- (1-acetylpropyl-1-yl) -1-L-sodium glutamate 5-methylester was obtained. Next, 500 ml of 25% ammonia water was added to the reaction solution, and the mixture was stirred for 2 hours. The solution was concentrated under reduced pressure at a bath temperature of 5 CTC or less to 20 g to obtain a concentrated oil of N- (1-acetylpropene-12-yl) -1-L-glutamine sodium. Then, 17 ml of methanol, 8 ml of acetic acid, and 8 ml of water were sequentially added to the concentrated oil. Under ice cooling, a small amount of L-glutamine seed crystal was added, and crystals precipitated from the solution. The crystals were collected by filtration, washed with methanol, and the obtained crystals were dissolved in 4 Om1 of water, adjusted to pH 5.5 with aqueous ammonia, and filtered. Bath temperature 40. The solution was concentrated under reduced pressure to about half the volume under C, and 22 ml of methanol was slowly added to the obtained solution, stirred overnight, and the crystals were collected by filtration. The obtained crystals were washed with methanol and then with ether, and dried under reduced pressure at 40 ° C or lower. The yield of L-glutamine was 3.20 g.

Melting point: 186 ° C (decomposition)

Specific rotation: [α] ο ² ° 10 Omm, C = 2% (2 N-HC 1) 32.3 ° Example 4

5.0 g of L-glutamic acid 5-methyl ester was suspended in 50 ml of methanol. Under stirring, 5 Oml of a methanol solution containing 1.24 g of caustic soda was added dropwise, and the solution became clear about 20 minutes after the start of the addition. Next, a 25 ml solution of methanol in which 3.8 g of methyl acetate was dissolved was added dropwise. After the addition was completed, the mixture was refluxed for 30 minutes. Under cooling, 26 g of liquid ammonia was added, and the mixture was stirred for 3 hours. At a bath temperature of 50 ° C or less, concentrate under reduced pressure until the amount becomes 20 g. A concentrated oil was obtained. Then, 17 ml of methanol, 8 ml of acetic acid and 8 ml of water were sequentially added. Under ice cooling, a small amount of L_glutamine seed crystal was added, and crystals precipitated from the solution. The crystals were collected by filtration, washed with methanol, and the obtained crystals were dissolved in 40 ml of water, the pH was adjusted to 5.5 with aqueous ammonia, and the mixture was filtered. The solution was concentrated under reduced pressure at a bath temperature of 40 ° C. or lower until the volume was reduced to about half, and 22 ml of methanol was slowly added to the concentrated solution, stirred overnight, and the crystals were collected by filtration. The obtained crystals were washed with methanol and then with ether, and then dried under reduced pressure at 40 ° C or less. The yield of L-glutamine was 3.20.

Melting point: 186 ° C (decomposition)

Specific rotation: [a] _D ² . 1 0 Omm C-2% (2 N-HC 1) 3 2.3 ° Industrial availability

According to the present invention, high-purity L-glutamine can be industrially produced at low cost by a synthesis method without using dangerous carbon disulfide.

Claims

The scope of the claims

1. The following general formula (Formula 1):

R ^, OCOCH ₂ CH ₂ CHCOOH

Man

CH ₃ -CH

CH 0

\

C

R ²

(Wherein, R ¹ represents hydrogen or a lower alkyl group, and R ² represents a lower alkyl group or a lower alkyloxy group). A method for producing L-daltamine or a salt thereof, wherein the protecting group is removed after the reaction.

2. The following general formula (Formula 2):

R'OCOCH ₂ CH ₂ CHCOOH

NH ₂

(Wherein, R ¹ represents hydrogen or a lower alkyl group) and a compound represented by the formula: CH ₃ COCH ₂ C〇—R ² (where R ² is a lower alkyl group) Or a lower alkyloxy group) to protect the amino group, then selectively amidate at the r-position, and remove the protecting group after the reaction. —A method for producing glutamin or a salt thereof.

3. The following general formula (Formula 3):

R ³ OCOCH ₂ CH ₂ CHCOOH

/ N

CHa-C H

II

CH 〇

\ ノ /

C I

R ²

(Wherein, R ³ represents a lower alkyl group, and R ² represents a lower alkyl group or a lower alkyloxy group) or a salt thereof.