Studies on Reactions of Cyclic Oxalyl Compounds with Hydrazines or Hydrazones. 2. Synthesis and Reactions of 4-Benzoyl-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic Acid

4-Benzoyl-1-(4-nitrophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid, obtained from the corresponding furan-2,3-dione and N-benzylidene-N'-(4-nitrophenyl)hydrazine, was converted via reactions of its acid chloride with various alcohols or N-nucleophiles into the corresponding ester or amide derivatives. The nitrile of the starting acid and 1-(4-aminophenyl)-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid were also obtained. While cyclocondensation reactions of the two acids and the nitrile mentioned with hydrazines lead to pyrazolo[3,4-d]pyridazine derivatives, the reaction of starting acid with 2-hydrazinopyridine provided the hydrazonopyrazole acid derivative.