(4R,5S,6S)-6-((R)-1-Hydroxy-ethyl)-4-methyl-3-[(3S,5S)-5-(2-methyl-isoxazolidin-5-yl)-1-(4-nitro-benzyloxycarbonyl)-pyrrolidin-3-ylsulfanyl]-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester

p-nitrobenzyl (1R,5S,6S)-2-(1-{4-[(3S)-1-(p-nitrobenzyloxycarbonyl)-pyrrolidin-3-ylcarbamoyl]-1,3-thiazol-2-yl}azetidin-3-yl)thio-6-[(R)-1-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylate

p-nitrobenzyl (1R,5S,6S)-2-(1-{4-[(3R)-1-(p-nitrobenzyloxycarbonyl)-pyrrolidin-3-ylcarbamoyl]-1,3-thiazol-2-yl}azetidin-3-yl)thio-6-[(R)-1-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylate

p-nitrobenzyl (1R,5S,6S)-2-{1-[4-(3-methoxyazetidine-1-carbonyl)-1,3-oxazol-2-yl]azetidin-3-yl}thio-6-[(R)-1-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylate

p-nitrobenzyl (1R,5S,6S)-2-(1-{4-[(3S)-1-(p-nitrobenzyloxycarbonyl)-pyrrolidin-3-ylcarbamoyl]-1,3-oxazol-2-yl}azetidin-3-yl)thio-6-[(R)-1-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylate