反应详情

In a dry flask (3R,4R)-3-[(R)-1-phenyl-ethylamino]-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester (31.32 g, 83.0 mmol) was dissolved in ethanol (400 mL). Potassium carbonate (68.72 g) was added and the mixture was refluxed for 6 hours. The reaction mixture was cooled, filtered through a bed of celite, and concentrated in vacuo to give a crude oil. Purification by flash column chromatography (20-50% ethyl acetate/hexanes) provided a colorless oil (4.59 g, 15%). Unepimerized ester was also isolated (23.49 g, 75%). 1H NMR (300 MHz, CDCl3), δ: 7.25 (t, J=5, 2H), 7.245 (t, J=2, 2H), 7.20 (d, J=5, 1H), 4.19 (q, J=7, 2H), 3.94 (bd, J=13, 2H), 3.86 (m, 2H), 2.85 (m, 1H), 2.71 (m, 2H), 2.32 (d, J=7, 2H), 2.20 (d, J=15, 1H), 1.68 (bs, 3H), 1.51 (s, 9H). MS (ESI), m+/z: (M+H)+=377.

1. temperaturethe mixture was refluxed for 6 hours
2. temperatureThe reaction mixture was cooled
3. filtrationfiltered through a bed of celite
4. concentrationconcentrated in vacuo
5. customto give a crude oil
6. customPurification by flash column chromatography (20-50% ethyl acetate/hexanes)