(6
R)-3
t-hydroxy-3
c-methyl-8-oxo-7
t-(2-phenoxy-acetylamino)-(6
rH)-5-thia-1-aza-bicyclo[4.2.0]octane-2
c-carboxylic acid 2,2,2-trichloro-ethyl ester 在
silica gel 作用下,
生成
(1S,4S,5R,8R)-1-Methyl-3-oxo-4-(2-phenoxy-acetylamino)-2-oxa-6-thia-9-aza-bicyclo[3.2.2]nonane-8-carboxylic acid 2,2,2-trichloro-ethyl ester