3-((2S,4S)-4-Mercapto-1-(((4-nitrobenzyl)oxy)carbonyl)pyrrolidine-2-carboxamido)benzoic acid

This compound is a sulfur-containing pyrrolidine derivative featuring a carboxybenzyl-protected amine and a nitrophenyl carbonate group. It serves as a key intermediate in the manufacture of the carbapenem antibiotic ertapenem.