Benzyl Bromide → 1,3-Dibenzylpiperidin-4-one

Reaction equation

[CH2:1]([N:8]1[CH2:13][CH2:12][C:11](=[O:14])[CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[H-].[Na+].[CH2:17](Br)[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1>O1CCCC1>[CH2:1]([N:8]1[CH2:13][CH2:12][C:11](=[O:14])[CH:10]([CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[CH2:9]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

Procedure

1-Benzylpiperidin-4-one (10 g, 53.0 mmole) was added to the stirred suspension of sodium hydride (1.8 g, 53.0 mmole) in tetrahydrofuran (50 ml) at 10° C. The reaction mixture was stirred for 15 min, benzyl bromide (9.0 g, 53.0 mmole) was added at 10° C. The resulting mixture stirred at room temperature for 4 hr and concentrated to dryness. The residue was triturated with water, extracted with ethyl acetate, dried (Na2SO4) and concentrated to give crude product, which was purified through column chromatography. Elute from 10% ethyl acetate in hexane afforded 1,3-dibenzylpiperidin-4-one. Yield 1.8 g (13%), C19H21NO, m/z 280 (M+1), PMR (CDCl3): 2.22-2.62 (4H, m, H2 & H6), 2.86 (2H, m, H5), 3.2 (1H, dd, H3, j=12 Hz), 3.45 (2H, m, CH2Ar), 3.68 (2H, m, N—CH2Ar), 7.1-7.4 (10, m, ArH).