(
S)-2-[(2
S)-2
r-acetoxy-4-oxo-3
t-(2-phenyl-acetylamino)-azetidin-1-yl]-3-mercapto-3-methyl-butyric acid methyl ester 在
silica gel 作用下,
生成
(S)-2,2-dimethyl-7-oxo-6-(2-phenyl-acetylamino)-2,3,4,7-tetrahydro-[1,4]thiazepine-3-carboxylic acid methyl ester