Toray Industries, Inc.

Toray Fine Chemicals Co., Ltd.

Toshihiro Fujino

Haruyo Sato

Seiji Morii

Sakie Nakai

When a salt of an amine and an optically active diacyltartaric acid, or a diastereomer salt of an optically active amine and an optically active diacyltartaric acid, obtained by optically resolving a racemic amine using the optically active diacyltartaric acid, is salt-exchanged with an acid aqueous solution, the optically active diacyltartaric acid is added in the acid aqueous solution beforehand. Furthermore, a raw material containing a racemic amine and an optically active diacyltartaric acid is optically resolved, and the diastereomer salt of the optically active amine and the optically active diacyltartaric acid respectively of one isomer type, is separated. The obtained diastereomer salt is dissociated using an acid aqueous solution containing the optically active diacyltartaric acid, for recovering the optically active diacyltartaric acid, and the obtained optically active diacyltartaric acid is recycled into an optical resolution step as a raw material of the optical resolution step.

Processes for the recovery of optically active diacyltartaric acids

Disclosed are a method for producing racemic piperidine derivatives by processing optically-active piperidine derivatives in a hydrogen atmosphere in the presence of a reducing catalyst; and a method for producing optically-active piperidine derivatives or their acid salts by optically resolving the racemic piperidine derivatives obtained in the former method.

Processes for producing racemic piperidine derivative and for producing optically active piperidine derivative

Method for producing optically-active 2-piperazinecarboxylic acid

An industrial process for producing O,O'-diacyltartaric anhydride with high purity and high efficiency is disclosed. According to the process of the invention, a carboxylic acid of the formula (I):

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Kuwana, Japan

Toshihiro Fujino