t-butyl 3-acetoxymethyl-7α-methoxy-2-methylene-3-cephem-4-carboxylate 1β-oxide

t-butyl 3-acetoxymethyl-7α-methoxy-2α-methyl-3-cephem-4-carboxylate 1,1-dioxide

t-butyl 3-acetoxymethyl-7α-methoxy-2β-methyl-3-cephem-4-carboxylate 1,1-dioxide

t-butyl 3-acetoxymethyl-7α-methoxy-2-methylene-3-cephem-4-carboxylate 1,1-dioxide

(4S,5S,6R,7S)-3-Acetoxymethyl-7-methoxy-4-methyl-5,8-dioxo-5λ4-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid tert-butyl ester

(4R,5S,6R,7S)-3-Acetoxymethyl-7-methoxy-4-methyl-5,8-dioxo-5λ4-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid tert-butyl ester