The present invention provides a simple industrial process for producing an L- or D-optically active α-methylcysteine derivative or its salt, which is a useful pharmaceutical intermediate, from readily available, inexpensive raw materials. In a process for producing an L- or D-optically active α-methylcysteine derivative or its salt, a racemic N-carbamoyl-α-methylcysteine derivative or its salt is D-selectively cyclized with hydantoinase to produce a D-5-methyl-5-thiomethylhydantoin derivative or its salt and an N-carbamoyl-α-methyl-L-cysteine derivative or its salt, which are then subjected to deprotection of the amino group and the sulfur atom, and hydrolysis.
本发明提供了一种简单的工业过程,用于从易得、廉价的原料中生产L-或D-光学活性α-甲基半胱
氨酸衍
生物或其盐,该衍
生物是一种有用的药物中间体。在生产L-或D-光学活性α-甲基半胱
氨酸衍
生物或其盐的过程中,使用外消旋N-
氨基甲基半胱
氨酸衍
生物或其盐与
咪唑二酮酶D-选择性环化,以产生D-5-甲基-5-
硫甲基
咪唑二酮衍
生物或其盐和N-
氨基甲基-
L-半胱氨酸衍
生物或其盐,然后对
氨基团和
硫原子进行去保护作用,并进行
水解。