(5R,6S)-6-[(1R)-1-Hydroxyethyl]-3-[[(3S)-1-[[(4-nitrophenyl)methoxy]carbonyl]-3-pyrrolidinyl]thio]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid (4-nitrophenyl)methyl Ester is an intermediate in synthesizing Panipenem (P180000), a broad spectrum carbapenem antibacterial and antimicrobial agent working against Gram-negative and Gram-positive organisms.