Addition of 1 to two moles of phenylhydrazine gives -tetraphenyl-(2,3-
d)-pyrazolo-5,6-pyridazine-7-one 4 isomer compound 1,2,3,5-tetraphenyl
-(2,3-d) pyrazolo-5,6-pyridazine-7-one 5 of 4 was synthesized by the r
eaction of 2 with phenylhydrazine. Diphenyl-(2,3-d)-pyrazolo-(1H,6H)-p
yridazine-7-one 6 was also obtained in two different ways. Reaction of
1 and 4-benzoyl-5 phenyl-furan-2,3-dione 3 with hydrazinium hydrate f
urnished compound 6. The structures of 4,5 and 6 were determined by th
e (13) C-NMR, IR spectra and elemental analysis. These new isomer and
condensed compounds synthesized in this study are important for hetero
cyclic chemistry.