反应详情

Iodomethane (20.5 ml, 329 mmol) was added to a solution of (4-bromo-3,5-dimethyl-phenyl)-carbamic acid tert-butyl ester (47.5 g, 158 mmol) and cesium carbonate (80.6 g, 247 mmol) in DMF (165 ml) at room temperature, and the mixture was stirred for 27 hours. Further, cesium carbonate (26.9 g, 82.6 mmol) and iodomethane (20.5 ml, 329 mmol) were added at room temperature, and the mixture was further stirred for three days. An aqueous ammonium chloride solution was added to the reaction mixture, followed by extraction with ethyl acetate. The organic layer was sequentially washed with water and saturated brine and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane-ethyl acetate) to give (4-bromo-3,5-dimethyl-phenyl)-methyl-carbamic acid tert-butyl ester (9.34 g, 92%).

1. stirringthe mixture was further stirred for three days
2. extractionfollowed by extraction with ethyl acetate
3. washThe organic layer was sequentially washed with water and saturated brine
4. concentrationconcentrated under reduced pressure
5. customThe resulting residue was purified by silica gel column chromatography (hexane-ethyl acetate)