Synthesis
General procedure for the synthesis of 2-bromo-2',4'-dichloroacetophenone from 2,4-dichloroacetophenone: N-bromosuccinimide (0.37 mmol) was slowly added to a stirred solution of 2,4-dichloroacetophenone (0.37 mol, 1 equiv) in acetonitrile (40 mL). The reaction mixture was continued to be stirred for 10-15 minutes. Subsequently, p-toluenesulfonic acid (p-TsOH, 0.74 mmol, 2 eq.) was added to the reaction system and the mixture was heated to reflux for 4-5 h. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was cooled to room temperature, washed with saturated sodium bicarbonate solution and subsequently extracted with ethyl acetate (3 x 20 mL). The organic layers were combined, dried with anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. The resulting crude product was purified by silica gel column chromatography with the eluent being a solvent mixture of ethyl acetate and hexane (4:96, v/v), and the fractions on 100-200 mesh silica gel were collected to give the pure 2-bromo-2',4'-dichloroacetophenone.
References
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[2] Journal of Medicinal Chemistry, 2018, vol. 61, # 13, p. 5679 - 5691
[3] Polish Journal of Chemistry, 1981, vol. 55, # 2, p. 399 - 409
[4] Medicinal Chemistry Research, 2016, vol. 25, # 10, p. 2335 - 2348
[5] Bioorganic and Medicinal Chemistry, 2018, vol. 26, # 8, p. 1665 - 1674
