(6R,7R)-3-Acetoxymethyl-7-{(R)-2-[N'-(2-nitro-benzyloxycarbonyl)-hydrazino]-3-phenyl-propionylamino}-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester

(6R,7R)-3-acetyloxymethyl-7-<2-(3-hydroxy-2-pyridyl)-4-thiazolyl>acetylamino-8-oxo-5-thia-1-azabicyclo<4.2.0>oct-2-ene-2-carboxylic acid diphenylmethyl ester

(R)-3-Acetoxymethyl-5,5,8-trioxo-7-[1-pyridin-2-yl-meth-(Z)-ylidene]-5λ6-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester

benzhydryl 7-[(Z)-bromomethylidene]cephalosporanate

(R)-3-Acetoxymethyl-7-[1-cyano-meth-(Z)-ylidene]-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester