反应详情

To a solution of 2,2,4,4-tetramethyl-6-chromanoic acid (200 mg, 0.85 mmol) in 0.5 ml of AcOH was added Br2 (0.07 ml, 1.28 mmol). The resulting dark-orange solution was stirred at room temperature for overnight. The excess bromine was removed under reduced pressure. Then the solution was poured into 5 ml of water and extracted with ethyl acetate (3×3 ml). The combined ethyl acetate layers were further washed with NaHCO3 (sat.), brine and dried over MgSO4. After concentration, the residue was purified by column chromatography (silica gel, ethyl acetate/hexane 1/3) to yield the desired product (170 mg, as white solids.

1. customThe excess bromine was removed under reduced pressure
2. additionThen the solution was poured into 5 ml of water
3. extractionextracted with ethyl acetate (3×3 ml)
4. washThe combined ethyl acetate layers were further washed with NaHCO3 (sat.), brine
5. dry with materialdried over MgSO4
6. concentrationAfter concentration
7. customthe residue was purified by column chromatography (silica gel, ethyl acetate/hexane 1/3)