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

6-(1-hydroxy-ethyl)-4-methyl-3-(1-(4-nitro-benzyloxycarbonyl)-5-{3-[2-(4-pyrimidin-2-yl-piperazin-1-yl)-ethanesulfonyl]-thiazolidin-2-yl}-pyrrolidin-3-ylsulfanyl)-7-oxo-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester