Sodium Hydroxide → 5-(6-Trifluoromethyl-pyridin-2-ylamino)-pyrazolo[1,5-a]pyrimidine-3-carboxylic acid

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A mixture of ethyl 5-(6-(trifluoromethyl)pyridin-2-ylamino)pyrazolo[1,5-a]pyrimidine-3-carboxylate (344 mg, 0.98 mmol, 1.0 equiv), 2M aqueous sodium hydroxide solution (1.50 mL, 3.0 equiv) and ethanol (15 mL) was heated to reflux for 5 hours. After cooling, the precipitate was collected by filtration, washed with ethanol, and air dried. The resultant solid was suspended in 1.25 M HCl in methanol (16 mL) and then concentrated under vacuum. The residue was triturated (diethyl ether) to afford 355 mg (quant. yield) of 5-(6-trifluoromethyl-pyridin-2-ylamino)-pyrazolo[1,5-a]pyrimidine-3-carboxylic acid which was used without further purification. LCMS (ESI) m+H=324.2; 1H NMR (300 MHz, DMSO-d6) δ: 11.03 (s, 1H), 9.01 (d, 1H), 8.95 (d, 1H), 8.35 (s, 1H), 8.10-8.02 (m, 1H), 7.54 (d, 1H), 7.16 (d, 1H).

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