Method for optical resolution of dl-cysteine and (r,s)-1-(1-naphthyl)

Abstract

Method for optical resolution of DL-cysteine by (1) reacting DL-cysteine with formaldehyde to prepare DL-thiazolidine-4-carboxylic acid (DL-TCA), (2) forming diastereomer salts of D-TCA and of L-TCA by reacting DL-TCA with an optically active 1-(1-naphthyl)ethylamine, (3) separating said diastereomer salts by difference of the solubilities thereof in a solvent, (4) recovering D-TCA from said diastereomer salt of D-TCA and finally obtain D-cysteine, and recovering L-TCA from said diastereomer salt of L-TCA and finally obtain L-cysteine. Method for optical resolution of (R,S)-1-(1-naphthyl)ethylamine (R,S)-NEA by (1) reacting an optically active cysteine with formaldehyde to prepare an optically active thiazolidine-4-carboxylic acid, (2) forming diastereomer salts of (R)-NEA and of (S)-NEA by reacting (R,S)-NEA with optically active thiazolidine-4-carboxylic acid, (3) separating said diastereomer salts of (R)-NEA and of (S)-NEA by difference of the solubilities thereof in a solvent, (4) recovering (R)-NEA from said diastereomer salt of (R)-NEA, and recovering (S)-NEA from said diastereomer salt of (S)-NEA.