Bromine → 2-Bromo-1-(4-bromo-3,5-dimethoxyphenyl)ethanone

Participants

Reaction Steps

To a solution of 1-(4-bromo-3,5-dimethoxyphenyl)ethanone (0.895 g, 3.45 mmol) in anhydrous CH2Cl2 (5 mL) under a drying tube was added a freshly made solution of Br2 in CH2Cl2 (1.95 M, 1.9 mL, 3.7 mmol) dropwise. The reaction was stirred at room temperature for 30 min then neutralized with a solution of saturated aqueous NaHCO3. The mixture was diluted with CH2Cl2 and the layers were separated. The organics were washed with saturated aqueous NaHCO3 and brine then dried over MgSO4/Na2SO4 and concentrated in vacuo. The crude product was adsorbed onto silica gel (2.9 g) as a CH2Cl2 solution. Purification by chromatography (0-20% EtOAc-hexanes) gave 2-bromo-1-(4-bromo-3,5-dimethoxyphenyl)ethanone as a white solid (0.737 g, 63% yield). Large-scale synthesis of 2-bromo-1-(4-bromo-3,5-dimethoxyphenyl)ethanone was performed without chromatographic purification of the bromide.

Provenance & Evidence