ethyl 2-chloro-3-oxo-butyrate
4-phenyl-semicarbazide
2-chloro-3-(4-phenyl-semicarbazono)-butyric acid ethyl ester
sodium acetate
ethanol
diethyl 2-acetyl-3-cyanobutanedioate phenylsemicarbazone
triethyl 6a-amino-2,5-dimethyl-1,6-bis-(N'-phenylureido)-1,3a,6,6a-tetrahydropyrrolo<2,3-b>pyrrole-3,3a,4-tricarboxylate
4-Benzoyl-2,5-dimethyl-1-(3-phenyl-ureido)-1H-pyrrole-3-carboxylic acid ethyl ester
2,5-Dimethyl-1-(3-phenyl-ureido)-1H-pyrrole-3,4-dicarboxylic acid 3-ethyl ester 4-methyl ester
ethyl 4-cyano-2-methyl-5-phenyl-1-(N'-phenylureido)pyrrole-3-carboxylate