N-((6R,7S)-3-(acetoxymethyl)-7-methoxy-5,5-dioxido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carbonyl)-N-methyl-D-alanine

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

methyl 3-(acetoxymethyl)-7α-methoxy-8-oxo-5-thia-1-azabicyclo<4.2.0>oct-2-ene-2-carboxylate 5,5-dioxide

(6R,7S)-3-Acetoxymethyl-7-methoxy-5,5,8-trioxo-5λ6-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid ethyl ester