反应详情

A solution of 4-(3-bromo-phenyl)-4-(4-difluoromethoxy-3-methyl-phenyl)-oxazolidin-2-one (intermediate XVII-2) (5.1 g, 1 eq) in a 9:1-mixture of ethanol and water (50 ml) was added lithium hydroxide (9.2 g, 30 eq). The reaction was stirred at reflux for 3 hours. Then the mixture was allowed to cool to room temperature and concentrated at reduced pressure. The residue was extracted with ethyl acetate (3×20 ml), the combined organic layers were collected, dried over sodium sulphate and concentrated in vacuo. The residue was purified by chromatography on silica gel using a 5:1-mixture of cyclohexane and ethyl acetate as the eluent. There were obtained 4.8 g (93% of theory) of the (RS)-2-amino-2-(3-bromo-phenyl)-2-(4-difluoromethoxy-3-methyl-phenyl)-ethanol as a white solid.

1. temperatureat reflux for 3 hours
2. concentrationconcentrated at reduced pressure
3. extractionThe residue was extracted with ethyl acetate (3×20 ml)
4. customthe combined organic layers were collected
5. dry with materialdried over sodium sulphate
6. concentrationconcentrated in vacuo
7. customThe residue was purified by chromatography on silica gel using a 5