反应详情

The ketone of (a) above (3.2 g) was suspended in methanol under nitrogen and the temperature brought to -40° C. Sodium borohydride (0.3 g) was added portionwise. The mixture was stirred for 30 min and then concentrated in vacuo, azeotroping with tetrahydrofuran. Borane tetrahydrofuran complex (64 ml, 1.0M in tetrahydrofuran) was added and the mixture was heated at reflux overnight. The mixture was cooled and quenched carefully with methanol, and the mixture was then concentrated in vacuo. The resulting residue was dissolved in ethanol (100 ml) and potassium carbonate (4.2 g) was added. The mixture was heated at reflux for 12 h. The mixture was cooled and evaporated and the residue was extracted with ethyl acetate and water. The organic extract was washed with brine, dried (MgSO4) and evaporated to afford 3-hydroxy-2-methyl-2-phenylpiperidine as a white solid. 1H NMR (360 MHz, CDCl3) δ7.79 (2H, d, ArH), 7.40 (2H, t, ArH), 7.15-7.19 (1H, m, ArH), 3.89 (1H, mc), 2.89-3.01 (2H, m), 1.67-1.91 (4H, m), 1.39 (3H, s, CH3).

1. custombrought to -40° C
2. concentrationconcentrated in vacuo
3. customazeotroping with tetrahydrofuran
4. additionBorane tetrahydrofuran complex (64 ml, 1.0M in tetrahydrofuran) was added
5. temperaturethe mixture was heated
6. temperatureat reflux overnight
7. temperatureThe mixture was cooled
8. customquenched carefully with methanol
9. concentrationthe mixture was then concentrated in vacuo
10. dissolutionThe resulting residue was dissolved in ethanol (100 ml)
11. additionpotassium carbonate (4.2 g) was added
12. temperatureThe mixture was heated
13. temperatureat reflux for 12 h
14. temperatureThe mixture was cooled
15. customevaporated
16. extractionthe residue was extracted with ethyl acetate and water
17. extractionThe organic extract
18. washwas washed with brine
19. dry with materialdried (MgSO4)
20. customevaporated