ethyl 4-hydroxy-5-oxo-5H-indole-2-carboxylate

2-Benzyloxycarbonylamino-4-nitro-pentanedioic acid dimethyl ester

2-ethyl 7,9-dimethyl 3-nitro-4,5-dioxo-4,5-dihydro-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylate

dimethyl 7,8-dimethoxy-6-[3-methoxy-3-oxo-2-(phenylhydrazono)propyl]-5-nitro-2,4-quinolinedicarboxylate

6-Chloro-4-hydroxy-7-[methoxycarbonyl-(4-methoxycarbonyl-2-oxo-2,3-dihydro-oxazol-5-yl)-methyl]-5-oxo-5H-indole-2-carboxylic acid ethyl ester