反应详情

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.

1. customthe layers were separated
2. washThe organics were washed with saturated aqueous NaHCO3 and brine
3. dry with materialthen dried over MgSO4/Na2SO4
4. concentrationconcentrated in vacuo
5. customPurification by chromatography (0-20% EtOAc-hexanes)