Yield:1197231-80-3 64%

Reaction Conditions:

with thionyl chloride at 0 - 20;

Steps:

1.1

To a solution of 3-fluoro-4-(trifluoromethoxy)benzoic acid (1.00 g, 4.46 mmol) in ethanol (10 ml) was added thionyl chloride (1.33 g, 1 1.2 mmol) at 0°C. The reaction solution was slowly warmed to room temperature, and stirred at the same temperature overnight. The reaction solution was poured into saturated aqueous sodium bicarbonate solution, and extracted with ethyl acetate twice. The organic layer was combined, washed with saturated brine, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate = 10:0→9: 1) to give ethyl 3-fluoro-4-(trifluoromethoxy)benzoate (0.72 g, 64%) as a colorless and clear oil. 1H-NMR (DMSO-d₆) δ 1.33 (3H, t, J = 7.1Hz), 4.35 (2H, q, J = 7.1Hz), 7.77-7.73 (1H, m), 7.92-7.90 (1H, m), 8.00 (1H, dd, J= 10.6, 1.9Hz).

References:

WO2012/124825,2012,A1 Location in patent:Page/Page column 112; 113