反应详情

温度

16 °C

To a stirred solution of benzylamine (5.2 mL, 47 mmol) in acetonitrile (30 mL) was added aqueous NaHCO3 solution (20 mL, 1.8 M, 36 mmol). After cooling to 16° C., the crude product obtained in step A (3.46 g, 32.9 mmol) dissolved in acetonitrile (30 mL) was added slowly over 40 minutes. After addition, the solution was heated to reflux for 1 h. The solvent was evaporated in vacuo to approximate 25 mL volume and ethyl acetate (60 mL) added. The resulting solution was stirred for 15 minutes. The organic layer was separated, washed with water (60 mL), dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo and the residue purified by flash column chromatography (SiO2, 8:1 to 7:3 hexanes/ethyl acetate) to give 1-benzyl-2-methylpiperidin-4-one (3.9 g, 54%) as a brown oil: 1H NMR (CDCl3, 300 MHz) δ 7.39-7.26 (m, 5H), 3.96 (d, J=13.5 Hz, 1H), 3.45 (d, J=13.2 Hz, 1H), 3.03-2.95 (m, 2H), 2.56-2.51 (m, 2H), 2.39-2.31 (m, 2H), 2.28-2.24 (m, 1H), 1.17 (d, J=6.3 Hz, 3H).

1. additionwas added slowly over 40 minutes
2. additionAfter addition
3. temperaturethe solution was heated
4. temperatureto reflux for 1 h
5. customThe solvent was evaporated in vacuo to approximate 25 mL volume and ethyl acetate (60 mL)
6. additionadded
7. customThe organic layer was separated
8. washwashed with water (60 mL)
9. dry with materialdried over Na2SO4
10. filtrationfiltered
11. concentrationThe filtrate was concentrated in vacuo
12. customthe residue purified by flash column chromatography (SiO2, 8:1 to 7:3 hexanes/ethyl acetate)