反应详情

To a mixture of the above methyl 2,4-dimethylbenzoate (19.75 g) and activated aluminum neutral oxide (120 g) was added dropwise bromine (9.25 ml) while stirring at room temperature. The mixture was stirred at room temperature for 8 hours, and diluted with diethyl ether (1000 ml). Insoluble materials were filtered off, and washed with diethyl ether (500 ml). The combined filtrate was washed successively with 10% aqueous sodium thiosulfate solution, a saturated aqueous sodium hydrogen carbonate solution and brine. The filtrate was dried over magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was crystallized from methanol (40 ml) to give methyl 5-bromo-2,4-dimethylbenzoate (6.34 g) as colorless crystals. APCI-Mass m/Z 243/245 (M+H).

1. stirringThe mixture was stirred at room temperature for 8 hours
2. filtrationInsoluble materials were filtered off
3. washwashed with diethyl ether (500 ml)
4. washThe combined filtrate was washed successively with 10% aqueous sodium thiosulfate solution
5. dry with materialThe filtrate was dried over magnesium sulfate
6. customthe solvent was evaporated under reduced pressure
7. customThe residue was crystallized from methanol (40 ml)