4-Thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid,6-[(acetyloxy)[4,5,6,7-tetrahydro-5-(phenylmethyl)thieno[3,2-c]pyridin-2-yl]methyl]-6-bromo-7-oxo-, (4-nitrophenyl)methyl ester, (5R)-