(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

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

(6R,7S)-3-(chloromethyl)-7-methoxy-2-(pyrrolidine-1-carbonyl)-5-thia-1-azabicyclo[4.2.0]oct-2-en-8-one 5,5-dioxide

tert-butyl N-((6R,7S)-3-(hydroxymethyl)-7-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carbonyl)-N-methylglycinate