1-ethyl-4-hydrazino-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester → 8-Ethyl-4H-pyrazolo[4',3':5,6]pyrido[3,4-e][1,2,4]-triazolo[1,5-a]pyrimidin-5(8H)-one

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Reaction Steps

249 g. of 1-ethyl-4-hydrazino-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid, ethyl ester (1 mol.) are refluxed in 1.5 liters of dry dioxane together with 98 g. of ethoxymethylene cyanamide for 12 hours. After cooling to room temperature, the precipitated 8-ethyl-4H-pyrazolo[4',3':5,6]pyrido[3,4-e][1,2,4]triazolo[1,5-a]pyrimidin-5(8H)-one is filtered off and recrystallized from dimethylformamide, yield 135 g. (53%); m.p. 355°-356°.

Provenance & Evidence