Sodium; (5R,6S)-3-cyclohexylcarbamoyloxymethyl-6-((R)-1-hydroxy-ethyl)-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylate
Sodium; (5R,6S)-6-((R)-1-hydroxy-ethyl)-7-oxo-3-phenylcarbamoyloxymethyl-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylate
(5R,6S)-6-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-3-cyclohexylcarbamoyloxymethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester
(5R,6S)-6-[(R)-1-(tert-Butyl-dimethyl-silanyloxy)-ethyl]-7-oxo-3-phenylcarbamoyloxymethyl-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid allyl ester
Sodium; (5R,6S)-3-(4-carbamoyloxymethyl-phenoxymethyl)-6-((R)-1-hydroxy-ethyl)-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylate