HCID 135783976, compound → HCID 135783975, compound

Participants

Reaction Steps

16.2 G. of 1-ethyl-1,7-dihydro-4-(trifluoromethyl)-6H-pyrazolo[3,4-b]pyridin-6-one, dissolved in 250 ml. of absolute ethanol, are catalytically hydrogenated by means of rhodium on charcoal catalyst (5%) at a temperature of 90°-100°. The reaction is performed in an autoclave at a hydrogen pressure of 10 atm. for 14 hours. After cooling, the catalyst is filtered off and the solution evaporated to dryness. The residual 1-ethyl-1,4,5,7-tetrahydro-4-(trifluoromethyl)-6H-pyrazolo[3,4-b]pyridin-6-one is treated with hot hexane providing 13.3 g. (81.5%) of the compound, m.p. 129°-130°. Recrystallization from a mixture of benzene/petroleum ether (1:2) raises the melting point at 130°-132°.

Provenance & Evidence