Method for producing optically active pyrrolidone carboxylic acid or alkali metal salt thereof

Abstract

Provided is a method with which it is possible to produce, easily and at excellent yield, a pyrrolidone carboxylic acid of extremely high chemical purity and optical purity or an alkali metal salt thereof. A method for producing an optically active pyrrolidone carboxylic acid or an alkali metal salt thereof, the method including a step for adding an alkali metal hydroxide to a solution of optically active zinc pyrrolidone carboxylate dihydrate and filtering out a precipitate.

Description

technical field [0001] The present invention relates to a method for producing an optically active pyrrolidone carboxylic acid or an alkali metal salt thereof. Background technique [0002] Pyrrolidone carboxylic acid (PCA) is a compound useful not only as a cosmetic raw material but also as a raw material for pharmaceuticals and the like. Pyrrolidone carboxylic acid is synthesized by heating glutamic acid to undergo a self-cyclization reaction. As a production method, a solvent-free direct heating method, a high-pressure high-heat method in the presence of a solvent, a subcritical pressure heating method, and an enzymatic cyclization method (enzymatic cyclization method) are known. [0003] Japanese Patent Application Laid-Open No. 1-132560 (Patent Document 1) describes a solvent-free direct heating method. In the solvent-free direct heating method, the monovalent alkaline earth metal salt of glutamic acid in a solid state is heated to a temperature between 120° C. and 25...

AI Technical Summary

Problems solved by technology

However, there is no known method for producing pyrrolidonecarboxylic acid in a simple and high yield by removing zinc from the product without impairing the optical purity.

In such a case, it is known to use an ion exchange resin to remove zinc, but it is difficult to reduce it to about tens of ppm

[0008] As mentioned above, there is no known method of producing pyrrolidone carboxylic acid or its salt with high optical purity and high chemical purity (HPLC purity)