(6R,7R)-3-(Acetoxymethyl)-8-oxo-7-[(phenylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, (7R,7aR)-3-[(acetyloxy)methyl]-6-oxo-7-[(2-phenylacetyl)amino]-7,7a-dihydro-2H,6H-azeto[2,1-b][1,3]thiazine-4-carboxylic acid, (6R,7R)-3-(acetyloxymethyl)-8-oxo-7-[(2-phenylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, (7R)-7-(Phenylacetylamino)-3-(acetoxymethyl)cepham-3-ene-4-carboxylic acid, Cephalosporin G, (6R,7R)-3-(acetoxymethyl)-8-keto-7-[(2-phenylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, benzylcephalosporin, (6R,7R)-3-(acetyloxymethyl)-8-oxo-7-(2-phenylethanoylamino)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, Phenylacetamidocephalothin, (6R)-3-acetoxymethyl-8-oxo-7t-(2-phenyl-acetylamino)-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 7-(phenylacetamido)-3-(acetoxymethyl)-3-cephem-4-carboxylic acid