diphenylmethyl (6R, 7S)-7-(2'-thienyl)acetamido-7-methoxy-3-carbamoyloxymethyl-3-cephem-4-carboxylate
(6R)-7t-hydroxyoxalylamino-3-(hydroxyoxalylcarbamoyloxy-methyl)-7c-methoxy-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester
diphenylmethyl (6R,7S)-7-carbomethoxycarbonylamino-7-methoxy-3-carbamoyloxymethyl-3-cephem-4-carboxylate
diphenylmethyl (6R,7S)-7-carboxycarbonylamino-7-methoxy-3-carbamoyloxymethyl-3-cephem-4-carboxylate
diphenylmethyl (6R, 7S)-7-amino-7-methoxy-3-carbamoyloxymethyl-3-cephem-4-carboxylate