PURPOSE: To obtain the titled amino acid in high yield, by reacting β-chloroalanine with a hydrosulfide of an alkalie metal, or alkaline earth metal in the presence of a halide of alkali metal, alkaline earth metal or ammonium in a polar aprotic solvent.
CONSTITUTION: β-Chloroalanine is reacted with a hydrosulfide of an alkali metal or alkaline earth metal or ammonium hydrosulfide in the presence of a halide of alkalie metal, alkaline earth metal, or ammonium in a polar aprotic solvent (e.g., DMSO) to give cysteine. By the reaction in the aprotic solvent having high polarity, decomposition of β-chloroalanine, a raw material, is suppressed, the reaction at relatively low temperature is made possible by the solvent effect and promoting effect of the halide on substitution reaction, and this suppresses also decomposition of the raw material and the desired compound.
SOYA SUMIO
HIROMOTO KAZUHIKO
ISHIOKA RIYOUJI
