6-β-<(carboxy)methylsulfonamido>penicillanice acid sulfone

(5R)-3,3,6c-trimethyl-7-oxo-6t-(2-phenyl-acetylamino)-(5rH)-4-thia-1-aza-bicyclo[3.2.0]heptane-2c-carboxylic acid

benzyl (2S,5R,6R)-6-[(N-decanoyl-L-prolyl-L-threonyl-L-alanyl-L-asparaginyl)amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]-heptane-2-carboxylate

(2S,4S,5R,6R)-6-Allyloxycarbonylamino-3,3-dimethyl-4,7-dioxo-4λ4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid benzyl ester

benzyl (2S,5R,6R)-3,3-dimethyl-7-oxo-6-phthalisoimido-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate