Aminopyrazine → 2-(Trifluoromethyl)imidazo[1,2-a]pyrazine

Participants

Reaction Steps

To a solution of 2-aminopyrazine (5.25 g, 55.2 mmol) in ethanol (120 mL) was added 1-bromo-3,3,3-trifluoroacetone (5.73 mL, 55.2 mmol). The reaction was stirred at reflux for 20 h. After evaporation of solvent, the residue was partitioned between ethyl acetate and saturated aqueous sodium bicarbonate solution. The aqueous layer was extracted with ethyl acetate (3×). The combined organic phase was washed with brine, dried over magnesium sulfate and concentrated. The residue was purified by flash chromatography (silica gel, 1:1 ethyl acetate:hexane, then 100% ethyl acetate) to give 2.35 g of the title compound as a solid. 1H NMR (500 MHz, CDCl3) δ 8.02 (m, 2H), 8.13 (m, 1H), 9.22 (s, 1H). ESI-MS 188 (M+1).

Provenance & Evidence