Sodium Carbonate → (+/-)-1,3-dihydro-1-(1-{1-[1-(2-pyrazinyl)-1-ethyl]piperidin-4-yl}piperidin-4-yl)-2H-benzimidazol-2-one

Participants

Reaction Steps

A mixture of 1-(1-(2-pyrazinyl)-ethyl)-4-oxopiperidine (37 mg), 4-(2-oxo-1-benzimidazolinyl)piperidine (41 mg), 1,2-dichloroethane (0.75 mL), glacial acetic acid (0.011 mL) and sodium triacetoxyborohydride (60 mg) was stirred at room temperature for 48 h. The reaction mixture was poured into dichloromethane (5 mL) and saturated aqueous Na2CO3 (3 mL) and the layers separated. The aqueous layer was extracted with dichloromethane (2×5 mL) and the combined organic layers dried over Na2SO4 and concentrated under reduced pressure. Purification by preparative TLC, eluting with chloroform; 10% methanol; 1% NH4OH, followed by trituration with diethyl ether gave 35 mg of (±)-1,3-dihydro-1-(1-{1-[1-(2-pyrazinyl)-1-ethyl]piperidin-4-yl}piperidin-4-yl)-2H-benzimidazol-2-one as a colorless solid: 1H NMR (400 MHz, CDCl3) 9.77 (br s, 1H), 8.69 (d, 1H), 8.54 (dd, 1H), 8.46 (d, 1H), 7.35 (m, 1H), 7.11-7.03 (m, 3H), 4.39 (m, 1H), 3.73 (q, 1H), 3.11 (m, 3H), 2.90 (m, 1H), 2.35-2.55 (m, 5H), 2.11 (m, 2H), 1.92-1.61 (m, 6H), 1.44 (d, 3H). Analysis calculated for C23H30N6O.0.1 H2O.0.3 CHCl3 : C: 63.01, H: 6.92, N: 18.92 found C: 63.07, H: 6.96, N: 18.76.

Provenance & Evidence