Heterocyclizations of 5-methylpyrazol-3-amine with unsaturated arylaliphatic carboxylic acid derivatives
作者:V. V. Lipson、S. M. Desenko、M. G. Shirobokova、O. V. Shishkin、S. V. Shishkina
DOI:10.1134/s1070428006070153
日期:2006.7
Cyclocondensation of 5-methylpyrazol-3-amine with methyl cinnamate and arylmethylidene-malonic acids in DMF and methanol leads to the formation of 7-aryl-2-methyl-6,7-dihydropyrazolo[1,5-a]pyrimidin-5(4H)-ones. Arylmethylidenemalonic acids react with the title amine at a ratio of 1: 2 in nitrobenzene to give 4-aryl-3,5-dimethyl-1,7-dihydrodipyrazolo[3,4-b:4',3'-e]pyridines. Heterocyclizations of 5-methylpyrazol-3-amine with 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones or their precursors, para-substituted benzaldehydes and 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid) in all solvents (methanol, DMF, and nitrobenzene) give the corresponding 4-aryl-3-methyl-2,4,5,7-tetrahydropyrazolo[3,4-b]pyridin-6-ones. The structure of 3-methyl-4-(4-nitrophenyl)-2,4,5,7-tetrahydropyrazolo[3,4-b]pyridin-6-one was proved by X-ray analysis.