反应详情

To a solution of 6-amino-5-fluoro-benzoxazolin-2-one (0.97 g, 5.7 mmole) and 3-formyl-5,6-dihydro-2H-pyran (0.71 g, 6.3 mmole) in ethanol (40 ml) were added molecular sieves (4A, 1 g). The mixture was heated under reflux for 3 hours. Upon cooling, the reaction mixture was filtered and the filtrate was concentrated to yield a solid product, which was washed with ethanol. This product was dissolved in methanol (200 ml) and then sodium borohydride was added in portions at room temperature. Stirring was continued for hours. The reaction mixture was concentrated and water was added. The organic material was extracted with ethyl acetate. The combined extracts were washed with brine, dried over magnesium sulfate, and concentrated. The resulting residue was recrystallized from methanol to afford 420 mg of the title product (28%): m.p. 175°-176° C.

1. temperatureThe mixture was heated
2. temperatureunder reflux for 3 hours
3. temperatureUpon cooling
4. filtrationthe reaction mixture was filtered
5. concentrationthe filtrate was concentrated
6. customto yield a solid product, which
7. washwas washed with ethanol
8. dissolutionThis product was dissolved in methanol (200 ml)
9. additionsodium borohydride was added in portions at room temperature
10. waitwas continued for hours
11. concentrationThe reaction mixture was concentrated
12. additionwater was added
13. extractionThe organic material was extracted with ethyl acetate
14. washThe combined extracts were washed with brine
15. dry with materialdried over magnesium sulfate
16. concentrationconcentrated
17. customThe resulting residue was recrystallized from methanol