反应详情

A mixture of 1.5 g of 1,3-dihydro-1-(4-oxocyclohexyl)-2H-benzimidazol-2-one, 1.12 g of ethyl 4-amino-1-piperidinecarboxylate, 20 mL of 1,2-dichloroethane, 0.40 mL of glacial acetic acid and 1.79 g of sodium triacetoxyborohydride was stirred at room temperature for 48 h. The reaction mixture was poured into 50 mL chloroform and 50 mL saturated aqueous Na2CO3 and the layers separated. The aqueous layer was extracted with 2×25 mL of chloroform and the combined organic layers dried over MgSO4 and concentrated under reduced pressure. Chromatography of the crude product on silica gel, eluting with 10% methanol in ethyl acetate gave 1.3 g of 1,3-dihydro-1-{trans-4-[1-ethoxycarbonyl-4-piperidinylamino]-1-cyclohexyl}-2H-benzimidazol-2-one as a white solid: 1H NMR (400 MHz, CDCl3) 9.8-9.9 (br m, 1H), 7.30 (m, 1H), 7.11-7.02 (m, 4H), 4.37 (m, 1H), 4.17-4.06 (m, 4H), 3.15 (m, 1H), 2.88 (t, 2H), 2.7 (m, 1H), 2.55 (m, 2H), 1.97 (d, 2H), 1.86 (d, 2H), 1.65 (q, 4H), 1.25 (m, 5H). Analysis calculated for C21H30N4O3C: 65.26, H: 7.82, N: 14.46 found C: 65.20, H: 7.57, N: 14.15.

1. customthe layers separated
2. extractionThe aqueous layer was extracted with 2×25 mL of chloroform
3. dry with materialthe combined organic layers dried over MgSO4
4. concentrationconcentrated under reduced pressure
5. washChromatography of the crude product on silica gel, eluting with 10% methanol in ethyl acetate