Sodium Bicarbonate → 6-Bromo-3-(trifluoromethyl)-(1,2,4)triazolo(4,3-a)pyridine

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A mixture of polyphosphoric acid (20 mL, 175 mmol) and N′-(5-bromopyridin-2-yl)-2,2,2-trifluoroacetohydrazide (1.9 g, 6.69 mmol) was stirred at 120° C. for 20 hours and then poured in to water. The mixture was then basified with saturated aqueous sodium bicarbonate solution and extracted with dichloromethane (3×250 mL). The organic phases were combined and washed with brine (1×100 mL), dried with MgSO4 and evaporated to give an involatile residue. The residue was purified by flash chromatography on silica-gel using an increasing gradient of ethyl acetate in isohexane as eluant to give 6-bromo-3-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyridine (1.39 g, 78%) as a beige solid.

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