The 7-hydrazino-3,4-diphenyl-2H-pyrazolo-[3,4-d]-pyridazine 3, obtained in 2 different ways consisting of the reactions of anhydrous hydrazine with 4-benzoyl-5-phenyl-2,3-dihydro-2,3-furandione 1 or 3,4-diphenyl-2H-pyrazolo-[3,4-d]-pyridazin-7(6H)-one 2, was converted into hydrazone derivatives 4 by the reactions of 3 with various salicylaldehydes.
ŞENER, AHMET (2004) "One Step Synthesis and Some Reactions of 7-Hydrazino-3,4-Diphenyl- 2H-Pyrazolo [3,4-d] Pyridazine," Turkish Journal of Chemistry: Vol. 28: No. 1, Article 5. Available at: https://journals.tubitak.gov.tr/chem/vol28/iss1/5