(6R)-7t-benzoylamino-3-methyl-7c-methylsulfanyl-8-oxo-(6rH)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid methyl ester

benzhydryl 3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

allyl (6R,7R) 7-phenoxyacetamido-1,1-dioxo-2-phenylselenomethyl-10-desacetoxyceph-3-em-4-carboxylate

(6R,7R)-7-{2-[1-(3-Methoxy-phenyl)-1H-tetrazol-5-ylsulfanyl]-acetylamino}-3-methyl-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid

(R)-3-(1-Methyl-1H-tetrazol-5-ylsulfanylmethyl)-5,5,8-trioxo-5λ6-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid tert-butyl ester