反应详情

温度

120 °C

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.

1. extractionextracted with dichloromethane (3×250 mL)
2. washwashed with brine (1×100 mL)
3. dry with materialdried with MgSO4
4. customevaporated
5. customto give an involatile residue
6. customThe residue was purified by flash chromatography on silica-gel