(6R)-3-acetoxymethyl-7t-((S)-3-tert-butoxycarbonylamino-3-phenyl-propionylamino)-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid 生成
(6R)-3-acetoxymethyl-7t-((R)-3-amino-3-phenyl-propionylamino)-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid