3-Chloro-5-oxo-1,5-dihydro-pyrrole-2,2-dicarboxylic acid dimethyl ester

Proline,3-chloro-3,4-didehydro-1-[N-[(1,1-dimethylethoxy)carbonyl]-L-valyl]-2-(methoxycarbonyl)-5-oxo-, methyl ester

diethyl 1-((tert-butoxycarbonyl)-L-valyl)-3-chloro-5-oxo-1,5-dihydro-2H-pyrrole-2,2-dicarboxylate