Water → 1-Methyl-2,6-diphenylpiperidin-4-one

Reaction equation

[C:1]1([CH:7]=[CH:8][C:9](=[O:18])[CH:10]=[CH:11][C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[CH3:19][NH2:20].O>CN(C)C=O>[C:1]1([CH:7]2[CH2:8][C:9](=[O:18])[CH2:10][CH:11]([C:12]3[CH:13]=[CH:14][CH:15]=[CH:16][CH:17]=3)[N:20]2[CH3:19])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

Procedure

1,5-Diphenyl-1,4-pentadien-3-one (20b, 4.00 g, 17.1 mmol) was dissolved in dimethyl formamide (60 ml). Methylamine (51, 6.0 ml, 70.0 mmol, 40% in water) was added and the mixture stirred for 96 hr at room temperature. The mixture was poured into water (250 ml) and stirred for 1 hr at room temperature. The resulting mixture was extracted into ethyl ether, washed with saturated sodium chloride, dried over magnesium sulfate, filtered and evaporated to afford a solid. The crude solid was recrystallized from ethanol to give 2.74 g (60%) of a white solid: mp 147-149° C. [expected mp 148-150° C.]; 1H NMR δ 1.82 (s, 3H), 2.50, (dd, 2H, J=12.3, 2.5 Hz), 2.82 (t, 2H, J=13.3 Hz), 3.45 (dd, 2H, J=12.9, 2.4 Hz), 7.34, (m, 10H); 13C NMR: δ 40.8, 50.8, 70.2, 127.0, 127.6, 128.8, 143.1, 206.8.