反应详情

A solution of borane dimethyl sulphide complex (7.38 mL) was added to an ice cooled, stirred solution of methyl 7-(2,2-dimethylpropionylamino)-2H-chromene-8-carboxylate (Intermediate 12, 7.49 g) in anhydrous THF (100 mL) and the mixture was stirred at room temperature for two hours. The resulting mixture was cooled in an ice bath and water (2.6 mL) was added carefully followed successively by 3M sodium hydroxide (31 mL) and 50% hydrogen peroxide (16 mL). After stirring vigorously at room temperature for 45 minutes, the mixture was diluted with ethyl acetate and water and the layers were separated. The organic layer was washed with brine, dried (Na2SO4) and filtered. The filtrate was evaporated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 10-60% to give methyl 7-(2,2-dimethylpropionylamino)-3-hydroxychroman-8-carboxylate (3.46 g) as a white foam.

1. temperaturecooled
2. temperatureThe resulting mixture was cooled in an ice bath
3. stirringAfter stirring vigorously at room temperature for 45 minutes
4. customthe layers were separated
5. washThe organic layer was washed with brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. customThe filtrate was evaporated in vacuo
9. customthe residue was purified by chromatography on silica
10. washeluting with a mixture of ethyl acetate and cyclohexane with a gradient of 10-60%