Ethyl 4,4,4-trifluoro-3-oxobutanoate (3 g, 16.30 mmol) was dissolved in ethanol (30 mL) under argon protection and urea (978 mg, 16.30 mmol) was added with stirring. Subsequently, freshly prepared sodium ethoxide solution (made by reacting 750 mg of sodium metal with 30 mL of anhydrous ethanol) was added to the reaction system. The reaction mixture was heated to 90 °C and the reaction was stirred at this temperature for 24 hours. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, volatile solvents were removed by distillation under reduced pressure, and the residue was diluted with water (25 mL), acidified with 1N hydrochloric acid (10 mL) to pH < 7, and then extracted with ethyl acetate (2 x 40 mL). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the target product 6-(trifluoromethyl)uracil (650 mg, 22% yield) as a white solid. Thin layer chromatographic conditions: 5% methanol/dichloromethane (Rf=0.3).1H-NMR (DMSO-d6, 500MHz) data: δ 11.07 (s, 1H), 11.54 (s, 1H), 6.07 (s, 1H).
