JPS61129177A - Production of epoxysuccinic acid monoester derivative - Google Patents

Abstract

PURPOSE:An epoxysuccinic monoester, which is available in a reasonable price in industry, is used as a starting material to produce the title compound of high purity which is used as a drug or intermediate in high efficiency through a specific process with simple operations. CONSTITUTION:Crude epoxysuccinic acid monoester containing free epoxysuccinic acid as an impurity is allowed to react with an activator for carboxyls such as p-nitropenol to synthesize activated epoxysuccinic acid monoester. Then, the activated epoxysuccinic acid derived from epoxysuccinic acid as an impurity is removed as a solid insoluble. Subsequently, purified activated epoxysuccinic acid monoester is allowed to react with an amino group- containing compound such as an alkylamine to give an epoxysuccinic monoesteramide.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing epoxysuccinic acid monoester derivatives, and more specifically, to a highly purified epoxysuccinic acid monoester derivative useful for pharmaceutical use or as an intermediate. This paper relates to a method for efficiently manufacturing the product using hour wheel operation.

[Conventional technology]

Epoxysuccinic acid monoester monoamide has a thiol group that strongly inhibits the activity of proteolytic enzymes involved in the expression of activity, and has extremely low toxicity, making it an effective compound for the treatment of muscular dystrophy, myocardial infarction, and other muscle diseases. It is known that there is.

Conventional methods for synthesizing such epoxysuccinic acid monoester monoamides include (1) a method in which an acid chloride of an epoxysuccinic acid monoester and an amino group-containing compound are reacted in the presence of a base, and (2) N,N'-dicyclohexylcarbodiimide. A method using a condensing agent such as the following is known (for example, JP-A-55-115878).

[Problem that the invention seeks to solve]

However, these synthetic methods produce by-products of open epoxy rings and impurities derived from the condensing agent (for example, N,N'-dicyclohexylurea), so it takes several times to obtain the desired product with high purity. It requires recrystallization or purification by column chromatography, and is not suitable for industrial production.

As a method to solve these problems, the activated ester, which is a condensation product of epoxysuccinic acid monoester and a carboxyl group activator such as p-nitrophenol or N-hydroxysuccinimide, is once separated. ,
One possible method is to react with an amino group-containing compound to obtain the target compound. However, if this method is applied to the raw material of crude epoxysuccinic acid monoester (epoxysuccinic acid monoester containing epoxysuccinic acid as an impurity), which is industrially available at low cost, the by-product of epoxysuccinic acid diamide will be produced. Unavoidably, several recrystallizations or purification by column chromatography were ultimately necessary to obtain the desired product with high purity.

[Means for solving problems]

Therefore, the present inventors conducted extensive research on a method for efficiently producing high-purity epoxysuccinic acid monoester monoamide using crude epoxysuccinic acid monoester, which is industrially available at low cost, as a raw material, and as a result, developed a specific process. The present inventors have discovered that by employing this method, a highly pure target product can be obtained efficiently with simple operations, and have completed the present invention.

Thus, according to the present invention, the step (A) of synthesizing an activated epoxysuccinic acid monoester by reacting a crude epoxysuccinic acid monoester component containing an epoxysuccinic acid component as an impurity with a carboxyl group activator; Step CB) of removing activated epoxysuccinic acid derived from epoxysuccinic acid from the product as a solid insoluble matter and purified activated epoxysuccinic acid monoester)? Provided is a method for producing an epoxysuccinic acid monoester derivative, comprising a step (C) of reacting the epoxysuccinic acid monoester monoamide with an amino group-containing compound.

The synthesis reaction of epoxysuccinic acid monoamide and stelmonoamide in the present invention generally proceeds as follows.

The crude epoxysuccinic acid monoester component used in the first step (A) means an epoxysuccinic acid monoester and/or its reactive derivative containing epoxysuccinic acid and/or its reactive derivative as an impurity. Epoxysuccinic acid monoester is usually synthesized by hydrolysis reaction of epoxysuccinic acid diester, but even when synthesized under selected reaction conditions, it usually contains several percent of epoxysuccinic acid. The epoxysuccinic acid referred to here refers to trans and cis forms, and although not particularly limited, the trans form is usually used from the viewpoint of medicinal efficacy.

Moreover, epoxysuccinic acid monoester is a compound in which one carboxyl group of the above-mentioned epoxysuccinic acid is esterified. R1 in the above general formula (1) is not particularly limited, and specific examples include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, and a cycloalkyl group. Although some of these may be appropriately substituted, those having 6 or less carbon atoms are usually used.

The activator used in the reaction is a drug that increases the reactivity of carboxyl groups, and is a compound commonly used in active esterification methods for peptide synthesis. Specific examples include phenols with an electron-withdrawing group in the ortho or rose position, N-hydroxylamine, etc. In particular, p-nitrophenol, 2,
Prizes include 4.5-trichlorophenol, pentachlorophenol, and N-hydroxysuccinimide.

In the reaction of step (A), the crude epoxysuccinic acid monoester and approximately equimolar or slightly excessive amount of the activating agent are usually mixed in an organic solvent at 70°C or lower, preferably between -30°C and 30°C, to remove the condensing agent. carried out in the presence of Any commonly used condensing agent may be used, and specific examples include N,
Examples include N'-dicyclohexylcarbodiimide, water-soluble carbodiimide, and N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline.

In the reaction, crude epoxysuccinic acid monoester can be converted into a reactive derivative such as an acid halide, acid azide, acid anhydride, etc. according to a conventional method, and then reacted with an activator. within the scope of the present invention.

The organic solvent used in the reaction may be one that does not participate in this reaction, and specific examples thereof include ethyl acetate, tetrahydrofuran, acetone, chloroform, dichloromethane, acetonitrile, N,N-dimethylformamide alone or a mixed solvent thereof. Illustrated. The amount of solvent to be used can be selected as appropriate, but is usually 2 to 10 times the amount of solute.

Through this reaction, an activated epoxysuccinic acid monoester corresponding to the above general formula (n) is synthesized. In the formula, R2
indicates the residue of the activator. In addition, the epoxysuccinic acid component contained in the crude epoxysuccinic acid monoester component similarly reacts with the activator during this process, and the activated epoxysuccinic acid (i.e., the above-mentioned The activator produces a condensation compound).

The reaction product obtained by step (A) is then subjected to step (A).
In B), activated epoxysuccinic acid contained as an impurity is removed as a fixed insoluble matter. Generally, methods such as recrystallization and column chromatography can be considered as methods for separating activated epoxysuccinic acid monoester and activated epoxysuccinic acid, but these methods are insufficient in terms of yield and operability. Epoxysuccinic acid can only be efficiently removed by utilizing the difference in solubility between the two in organic solvents.

In other words, in relatively highly polar solvents, the difference in solubility between the two compounds is small, but in relatively less polar solvents, activated epoxysuccinic acid has a lower solubility than activated epoxysuccinic acid monoester, leading to the formation of insoluble crystals. Form. Therefore, if the insoluble crystals of activated epoxysuccinic acid are removed by separation operations such as filtration and decantation, activated epoxysuccinic acid monoester can be easily purified. The activated epoxysuccinic acid monoester purified here may be subjected to the next reaction as a solution, or may be isolated by performing a concentration operation or the like.

The organic solvent used here may be one that is inert to the solute, such as aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane, heptane, and octane, and cyclopentane and cyclohexane. Hydrocarbon solvents such as alicyclic hydrocarbons alone or a mixture of these solvents are most effective in terms of solubility of solutes. Furthermore, it is also possible to use a mixed solvent system with esters such as ethyl acetate and butyl acetate, ethers such as diethyl ether and tetrahydrofuran, ketones such as acetone, chloroform, dichloromethane, acetonitrile, N,N-dimethylformamide, etc. . Further, the temperature conditions during dissolution and separation are preferably a constant temperature of -30°C to 70°C, preferably a constant temperature of 0 to 30°C.

The activated epoxysuccinic acid monoester purified in step (B) is then reacted with an amino group-containing compound in step (C) to obtain the epoxysuccinic acid monoester monoamide represented by the general formula (I [[)]. It is formed. In the formula, R3 represents an amino residue.

The amino group-containing compound used has primary or secondary amino groups in the molecule.
Examples thereof include alkylamines, dialkylamines, alkenylamines, alkynylamines, cycloalkylamines, cycloalkenylamines, amino acids, and amino acid derivatives.

The reaction is carried out using activated epoxysuccinic acid monoester and approximately the same amount or slightly excess amount of an amino group-containing compound in an organic solvent.
It is carried out at -30° to 70°C, preferably 0 to 30°C.

The organic solvent used is not particularly limited as long as it does not participate in this reaction, and specific examples thereof include ethyl acetate, tetrahydrofuran, acetone, chloroform, dichloromethane, acetonitrile, N,N-dimethylformamide, and the like.

After the reaction, extraction, washing, etc. are performed using conventional methods.
High purity epoxysuccinic acid monoester monoamide can be obtained by performing concentration, crystallization, etc., and recrystallizing if necessary.

〔Effect of the invention〕

Thus, according to the present invention, highly pure epoxysuccinic acid monoester monoamide can be efficiently obtained from inexpensive raw materials through convenient operations.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that the percentages in Examples, Reference Examples, and Comparative Examples are based on weight unless otherwise specified.

! 18.8 g of epoxysuccinic acid diethyl ester was dissolved in 100 ml of ethyl alcohol, 60 ml of an ethyl alcohol solution containing 5.9 g of KOH was added under water cooling, and after stirring for 2 hours, the ethyl alcohol was concentrated under reduced pressure and the residue was
After dissolving in 0 ml of water, unreacted epoxysuccinic acid diethyl ester is extracted and removed with 150 ml of ethyl acetate.

Furthermore, 70 ml of 2N hydrochloric acid was added to the aqueous layer, followed by extraction three times with 200 ml of ethyl acetate, and the ethyl acetate layers were combined, washed with water, dried, and concentrated to obtain 12 g of crude epoxysuccinic acid monoethyl ester. As a result of high performance liquid chromatography (hereinafter referred to as HPLC) analysis of this product, the purity of epoxysuccinic acid monoethyl ester was 94%, and it contained 6% epoxysuccinic acid.

Since epoxysuccinic acid monoethyl ester is in the form of an oil, it cannot be purified by recrystallization, etc., and removal of epoxysuccinic acid by washing the extracted ethyl acetate layer with water involves loss of epoxysuccinic acid monoethyl ester, making it difficult to carry out. I found out something.

6% epoxysuccinic acid as an impurity obtained in the reference example.
17.0g of crude epoxysuccinic acid monoethyl ester containing
, 21.5 g of L-leucylisoamylamide, 13.6 g of N-hydroxysuccinimide, and 250 g of ethyl acetate.
A solution of 24.4 g of N,N' dicyclohexylcarbodiimide in 100 ml of ethyl acetate was gradually added under water cooling, and the mixture was stirred for 2 hours while maintaining the same temperature, and further stirred for 1 hour at room temperature. After the reaction, N and N' precipitated
- After filtering off dicyclohexylurea, 5% hydrochloric acid 50
m1. il Japanese salt water 50ml1. 50ml of saturated sodium bicarbonate solution. The mixture was washed successively with 50 ml of saturated brine, dried over magnesium sulfate, and concentrated. The obtained crude crystals were recrystallized from acetone-hexane, and R3 in the general formula (II[) was an ethyl group,
23.9 g of crystals containing epoxysuccinic acid monoester monoamide in which R3 is an L-leucylisoamylamino residue as a main component were obtained.

As a result of HPLC analysis, the purity of the product was 97%, and N
, 0.5% of N'-dicyclohexylurea, and 2.0% of impurities derived from epoxysuccinic acid.

Comparative Example 2 6% epoxysuccinic acid was used as an impurity obtained in the reference example.
Crude epoxysuccinic acid monoethyl ester containing 17.0
g was dissolved in 88 ml of ethyl acetate, and while cooling with water, 15.0 g of para-nitrophenol was added and stirred. This results in N
, N'-dicyclohexylcarbodiimide 22.
A solution obtained by dissolving 2 g in 42 ml of ethyl acetate was cooled with water, and then reacted at the same temperature for 3 hours and then at room temperature for 1 hour. After the reaction, the precipitated N,N'-dicyclohexylurea was filtered off, and the filtrate was concentrated under reduced pressure. The obtained concentrate was crystallized from a mixed solution of ethyl acetate and n-hexane to obtain 25.5 g of crude mono-trans epoxysuccinic acid varanitrophenylethyl ester (Process A). E
(As a result of PLC analysis, the purity of L-transepoxysuccinic acid varanitrophenylethyl ester was 94.7%, and it contained 5.3% of L-1-transepoxysuccinic acid dipranitrophenyl ester.

25.5 g of the above roughened trans-epoxysuccinic acid varanitrophenylethyl ester 250 m of ethyl acetate
1 and L-leucylisoamylamide I7 to this.
．． A solution prepared by dissolving 9 g of ethyl acetate in 35 ml of ethyl acetate was added dropwise at room temperature, and the mixture was further reacted at the same temperature for 4 hours. After the reaction, insoluble matter was filtered off, and the filtrate was diluted with a 2% hydroxide l-U rum aqueous solution (75 m
Washed sequentially with 1XS times), saturated saline, and 5% hydrochloric acid saturated saline. After drying over anhydrous magnesium sulfate, it was concentrated to dryness under reduced pressure, and the resulting residue was crystallized from an acetone-n-hexane mixture to obtain 20.6 g of crystals.

As a result of HPLC analysis, the composition of the above product was 98.2% epoxysuccinic acid monoester monoamide in which R in the general formula (I[[) is an ethyl group and R3 is an L-leucylisoamylamino residue. The impurity derived from epoxysuccinic acid was 1.5%.

Purity 9 obtained by carrying out the reaction of process A in the same manner as in Comparative Example 2
25.5 g of 4.7% crude L-1-lance epoxysuccinic acid paranitrophenylethyl ester was dissolved in 80 g of toluene.
20 in a mixed solvent of 0 ml and 400 ml of n-hexane.
Stir at ℃ for 1 hour. After filtering off the insoluble crystals, the filtrate was concentrated and purified under reduced pressure to obtain 24.2 g of crystals of mono-trans epoxysuccinic acid varanitrophenylethyl ester (Process B). As a result of HPLC analysis, the purity of L-)lans epoxysuccinic acid varanitrophenylethyl ester was 99.0%. In addition, H of the insoluble crystals separated by filtration
From the PLC analysis results, it was found that most of the insoluble matter was di-trans-epoxysuccinic acid dipranitrophenyl ester, indicating that impurities were separated almost quantitatively.

Purified L-transepoxysuccinic acid varanitrophenylethyl ester 24.2 g 'c Ethyl acetate 25
A solution prepared by dissolving 16.8 g of L-leucylisoamylamide in 35 ml of ethyl acetate was added dropwise thereto at room temperature, and the mixture was further reacted at the same temperature for 4 hours. After the reaction, the filtrate was mixed with a 2% aqueous sodium hydroxide solution (75 ml x 5 times),
It was washed successively with saturated brine, 5% hydrochloric acid, and saturated brine. After drying over anhydrous magnesium sulfate, it was concentrated to dryness under reduced pressure, and the resulting concentrate was crystallized from an acetone-n-hexane mixture to obtain 20.4 g of product crystals (Process C).

As a result of HPLC analysis, the composition of the above product was 99.5% epoxysuccinic acid monoester monoamide in which R1 of the general formula (I[[) is an ethyl group and R3 is an L-leucylisoamylamino residue. The impurity derived from epoxysuccinic acid was 0.3%.

The reaction in Step A was carried out in the same manner as in Comparative Example 2, and IJIL-4 lance epoxysuccinic acid varanitrophenyl ethyl ester having a purity of 94.7% was obtained.

Then, 25.5 g of this crude mono-trans epoxysuccinic acid varanitrophenylethyl ester was added to 640 g of toluene.
m1. 25℃ in a mixed solvent of 320ml of cyclohexane
Stir for 1 hour. Thereafter, the same procedure as in Example 1 was carried out to obtain a product with a purity of 98.5%. ! ! ! Crystals of L-transepoxysuccinic acid varanitrophenylethyl ester 23.
8 g was obtained (Process B). Next, using the purified L-)lans epoxysuccinic acid varanitrophenylethyl ethyl ethyl ethyl ester, the reaction in step C was carried out in the same manner as in Example 1, followed by the isolation operation to obtain 19.8 g of product crystals. . As a result of HPLC analysis, the composition of the above product was 99.3% epoxysuccinic acid monoester monoamide in which R1 of the above general formula (II) is an ethyl group and R3 is an L-leucylisoamylamino residue, derived from epoxysuccinic acid. 0 impurities
．． It was 4%.

Patent applicant: Zeon Corporation Same Taisho Pharmaceutical Co., Ltd.

Claims (1)

[Claims] Step (A) of synthesizing an activated epoxysuccinic acid monoester by reacting a crude epoxysuccinic acid monoester component containing an epoxysuccinic acid component as an impurity with a carboxyl group activator; A process (B) of removing activated epoxysuccinic acid derived from as a solid insoluble matter and a process of reacting the purified activated epoxysuccinic acid monoester with an amino group-containing compound to synthesize an epoxysuccinic acid monoester monoamide (C) A method for producing an epoxysuccinic acid monoester derivative.