Allylamine → 4-(Allylamino)-1-benzylpiperidin-2-one

Participants

Reaction Steps

A mixture of 1-benzyl-piperidine-2,4-dione (508 mg, 0.25 mmol), allylamine (188 μL, 2.50 mmol) and 4 Å molecular sieves (500 mg) in DCE (5 mL) was stirred at ambient temperature for 5 hours, then sodium triacetoxyborohydride (106 mg, 0.50 mmol) was added. The resulting mixture was stirred for 16 hours, filtered through Celite®, and concentrated under vacuum. The resulting residue was dissolved in methanol (4 mL) and sodium borohydride (114 mg, 3.00 mmol) was added. The mixture was stirred for 40 hours and then concentrated under vacuum. The residue was dissolved in DCM and washed with 5% aqueous sodium bicarbonate, and dried over sodium sulfate and concentrated under vacuum. The residue was purified by column chromatography on silica gel (gradient: 0 to 80% methanol in DCM then 0 to 60% 2M NH3 in methanol solution in DCM) to afford 430 mg (70%) of racemic 4-allylamino-1-benzyl-piperidin-2-one. 1H NMR (400 MHz, CDCl3) δ: 7.29 (m, 5H), 5.89-5.85 (m, 1H), 5.20 (m, 2H), 4.85 (s, 1H), 4.61 (m, 2H), 3.95 (s, 1H), 3.68 (m, 1H), 3.29-3.25 (m, 2H), 3.10 (m, 1H), 2.75 (ddd, 1H), 2.33 (t, 1H), 1.99 (m, 1H), 1.70-1.57 (m, 1H).

Provenance & Evidence