General procedure for the synthesis of 2-bromo-5-trifluoromethylphenol from 3-trifluoromethylphenol: To a stirred solution of 61.65 g (0.38 mol) of 3-trifluoromethylphenol dissolved in 240 ml of carbon disulfide, 19.6 ml (0.38 mol) of bromine was slowly added dropwise. The reaction mixture was stirred continuously at room temperature for about 18 hours. Subsequently, the reaction solution was partitioned between 200 ml of dichloromethane and 100 ml of water. The organic phase was separated, washed with 20 mL of saturated aqueous sodium chloride, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using dichloromethane containing 40% hexane as eluent. The eluate containing the target product was collected and concentrated under reduced pressure to give 48.8 g (53% yield) of 2-bromo-5-trifluoromethylphenol as a yellow oil. Ion spray mass spectrometry (MS) analysis showed m/e = 239,241 (M + 1).
[1] Journal of the American Chemical Society, 1951, vol. 73, p. 1325
[2] Journal of Organic Chemistry, 1951, vol. 16, p. 586,606
[3] Patent: US6638936, 2003, B1
