General procedure for the synthesis of 3-trifluoromethyl-4-bromophenol from 3-trifluoromethylphenol: To a solution of 3-trifluoromethylphenol (7.50 mL, 62 mmol) was added dropwise bromine (3.47 mL, 68 mmol) and the reaction mixture was stirred overnight at room temperature. After completion of the reaction, the mixture was poured into water and extracted with dichloromethane. The organic layers were combined and washed sequentially with 4% sodium bicarbonate solution and saturated saline. The solvent was removed by distillation under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography with hexane/ethyl acetate solvent mixture as mobile phase. Finally, 5.17 g of 3-trifluoromethyl-4-bromophenol was obtained in 30% yield. lRMS: m/z 241 (M-1)+; retention time: 6.18 min (Method B). 1H NMR (400 MHz, CDCl3) δ 7.53 (d, J = 8.6 Hz, 1H), 7.19 (d, J = 2.9 Hz, 1H), 6.87 (dd. J = 8.6, 2.9 Hz, 1H), 5.98 (s, 1H).
