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

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 ofp- 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-acetyidimedone gave the corresponding 1-(4methoxyphenyl)-4-oxo-4, 5, 6, 7-tetrahydroindazole. In the case of 2 -formyldimedone the intermediate 2-(4methoxyphenylhydrazinomethylene)-5, 5-dimethyl-1,3-cyclohexanedione was isolated.Riga Technological University, Riga LV-1658. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 708–710, May, 1996. Original article submitted December 31, 1995.