Water → 4,5-Dihydro-7-[3-(trifluoromethyl)phenyl]pyrazolo[1,5-a]pyrimidine-3-carboxylic acid, ethyl ester

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Reaction Steps

To a 20.0 g amount of 7-(3-(trifluoromethyl)-phenyl)pyrazolo(1,5-a)pyrimidine-3-carboxylic acid, ethyl ester (U.S. Pat. No. 4,178,449, Example 16) stirred in 100 ml of glacial acetic acid and cooled in a water bath is added portionwise 10.0 g of sodium cyanoborohydride under nitrogen. The mixture is stirred at room temperature for 3 hours. Evaporation of the mixture in vacuo gives an oil which solidifies on treatment with water. This solid is collected by filtration and is then stirred with a saturated solution of sodium bicarbonate, then is filtered, washed with water and dried in vacuo to give a white solid. Recrystallization from isopropyl alcohol gives 18.2 g of the desired product, mp 108-110° C.

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