Synthesis
The general procedure for the synthesis of 2-bromo-2'-chloroacetophenone from o-chloroacetophenone is as follows: in a reaction system, 1.2 g (10 mmol) of o-chloroacetophenone 1a was mixed and stirred with 0.121 g (0.5 mmol) of Cu(NO3)2-3H2O while an oxygen bulb (ca. 0.5-1 L) was attached. Subsequently, an aqueous 8 mol/L hydrobromic acid solution (1.5 mL, 12 mmol) was slowly added dropwise to the mixture. The reaction mixture was stirred continuously at 70 °C and the reaction progress was monitored by TLC or GC. After completion of the reaction, the mixture was extracted with CH2Cl2. The organic extract was washed sequentially with 5% sodium sulfite solution, saturated sodium bicarbonate solution and water and finally dried with anhydrous magnesium sulfate. The solvent was removed under vacuum and the residue was purified by column chromatography (silica gel as stationary phase, petroleum ether/dichloromethane 3:1 v/v/v) to afford the target product 2-bromo-2'-chloroacetophenone (2a) in a yield of 1.81 g in 91%.
References
[1] Synthetic Communications, 2016, vol. 46, # 2, p. 165 - 168
[2] Patent: US2004/44057, 2004, A1
[3] Bioorganic and Medicinal Chemistry, 2014, vol. 22, # 2, p. 692 - 702
[4] Tetrahedron, 1998, vol. 54, # 43, p. 13059 - 13072
[5] Tetrahedron Letters, 2012, vol. 53, # 2, p. 191 - 195
