1-(1-phthalazinyl)- and 1-(4-methoxyphenyl)-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazole

Article abstract of DOI:10.1007/BF01164795

2-(1-Phthalazinylhydrazino)methylene- (IIIa) or 2-(1-phthalazinylhydrazino)ethylidene-5,5-dimethyl-1,3-cyclohexanediones (IIIb) were prepared from 1-hydrazinophthalazine and 2-formyl- or 2-acetyldimedone. Cyclization of IIIb in the presence of p-TsOH gave 1-(1-phthalazinyl)3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydroindazole. Reaction of 4-methoxyphenylhydrazine with 2-formyl- and 2-acetyldimedone gave the corresponding 1-(4-methoxyphenyl)-4-oxo-4,5,6,7-tetrahydroindazole. In the case of 2-formyldimedone the intermediate 2-(4-methoxyphenylhydrazinomethylene)-5,5-dimethyl-1, 3-cyclohexanedione was isolated. 1996 Plenum Publishing Corporation.