反应详情

A solution of 1-benzyl-4-ethylaminopiperidine-4-carbonitrile I-1A-1d (0.58 g, 2.38 mmol) in methylene chloride (2 ml) cooled in an ice bath was treated with H2SO4 (1.8 ml, 33 mmol), dropwise, while keeping the internal temperature below 20° C. The reaction mixture was then warmed to room temperature and stirred for 19 hours. After stirring was discontinued, the thick pale orange H2SO4 bottom layer was separated, cooled in an ice bath, and then carefully quenched with concentrated NH4OH keeping the internal temperature below 55° C. The aqueous layer was extracted with methylene chloride (2×10 ml), the combined organic layers were washed with brine (20 ml), dried (Na2SO4), and then concentrated, in vacuo, to afford I-1A-1e as a pale orange oil that solidified to a peach colored solid upon standing (0.54 g, 87%): +APcl MS (M+1) 262.2; 1H NMR (400 MHz, CD2Cl2) δ 7.34-7.30 (m, 4H), 7.29-7.21 (m, 1H), 7.16 (br s, 1H), 3.48 (s, 2H), 2.71-2.68 (m, 2H), 2.47 (q, J=7.0 Hz, 2H), 2.17-2.02 (m, 4H), 1.62-1.58 (m, 2H), 1.41 (br s, 1H), 1.09 (t, J=7.0 Hz, 3H).

1. customthe internal temperature below 20° C
2. stirringAfter stirring
3. customthe thick pale orange H2SO4 bottom layer was separated
4. temperaturecooled in an ice bath
5. customcarefully quenched with concentrated NH4OH keeping the internal temperature below 55° C
6. extractionThe aqueous layer was extracted with methylene chloride (2×10 ml)
7. washthe combined organic layers were washed with brine (20 ml)
8. dry with materialdried (Na2SO4)
9. concentrationconcentrated, in vacuo
10. customto afford I-1A-1e as a pale orange oil that solidified to a peach