ethyl γ-bromo-(4-nitrophenyl)azoacetoacetate
potassium cyanide
4-Cyano-2-[(4-nitro-phenyl)-hydrazono]-3-oxo-butyric acid ethyl ester
3-Acetyl-5-imino-2-methyl-6-(4-nitro-phenyl)-4-phenyl-5,6-dihydro-4H-pyrano[2,3-d]pyridazine-8-carboxylic acid ethyl ester
3-Acetyl-2-methyl-6-(4-nitro-phenyl)-5-oxo-4-phenyl-5,6-dihydro-4H-pyrano[2,3-d]pyridazine-8-carboxylic acid ethyl ester
2-Hydroxy-6-(4-nitro-phenyl)-5-oxo-4-phenyl-5,6-dihydro-4H-pyrano[2,3-d]pyridazine-3,8-dicarboxylic acid diethyl ester
2-Amino-6-(4-nitro-phenyl)-5-oxo-4-phenyl-5,6-dihydro-4H-pyrano[2,3-d]pyridazine-3,8-dicarboxylic acid 8-ethyl ester
6-(4-Nitro-phenyl)-5-oxo-2,4-diphenyl-5,6-dihydro-4H-pyrano[2,3-d]pyridazine-8-carboxylic acid ethyl ester