Synthesis
General procedure for the synthesis of 2-bromo-1-[4-(trifluoromethoxy)phenyl]ethanone from 4'-(trifluoromethoxy)acetophenone: To a preheated (80 °C) stirred solution of copper(II) bromide (17.2 g, 77.2 mmol) in ethyl acetate (20 mL) was slowly added 4'-(trifluoromethoxy)acetophenone (8.7 g, 42.89 mmol) in a chloroform (10 mL) solution. The reaction mixture was stirred continuously at 80 °C for 4 h, during which the progress of the reaction was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was filtered through a diatomaceous earth pad to remove solid impurities. The filtrate was subsequently concentrated under reduced pressure to give the crude product. The crude product was further purified by silica gel column chromatography with an eluent of 2-2.5% dichloromethane/hexane mixed solvent, resulting in the target compound 2-bromo-1-[4-(trifluoromethoxy)phenyl]ethanone (7 g, 58.0% yield) as an off-white solid. Its 1H NMR (400 MHz, CDCl3) data were as follows: δ 8.05 (d, J=8.0 Hz, 2H), 7.32 (d, J=8.8 Hz, 2H), 4.41 (s, 2H).
References
[1] Journal of Medicinal Chemistry, 2017, vol. 60, # 18, p. 7677 - 7702
[2] Patent: WO2018/165520, 2018, A1. Location in patent: Page/Page column 223
[3] Patent: WO2013/131408, 2013, A1. Location in patent: Page/Page column 128
[4] Journal of Medicinal Chemistry, 1996, vol. 39, # 1, p. 253 - 266
[5] Bioorganic and Medicinal Chemistry Letters, 2010, vol. 20, # 4, p. 1432 - 1435
