反应详情

A mixture of 16 (4.0 g, 16 mmol), nicotinaldehyde (1.89 mL, 20 mmol), and piperidine (4.0 mL, 40 mmol) in absolute EtOH (65 mL) was heated at reflux for 16 h. The mixture was cooled and concentrated in vacuo. Chromatography on silica gel (30-60% EtOAc/hexanes) gave a mixture of unreacted nicotinaldehyde and 17 (both have the same Rf on TLC). Washing of the mixture with hexane in a filter funnel provide 1.73 g (32%) of pure 17 as a yellow crystal. 1H NMR (CDCl3, 300 MHz) 8.87 (d, J=2.1 Hz, 1 H), 8.66 (dd, J=4.8, 1.5 Hz, 1 H), 7.97 (d, J=7.9 Hz, 1 H), 7.80 (d, J=16.7 Hz, 1 H), 7.66 (d, J=7.6 Hz, 1 H), 7.60 (d, J=15.9 Hz, 1 H), 7.55 (s, 1 H), 7.46 (t, J=7.8 Hz, 1 H), 7.38 (dd, J=7.9, 4.8 Hz, 1 H), 7.20 (dd, J=8.2, 2.6 Hz, 1 H), 4.62 (s, 2 H), 1.52 (s, 9 H); 13C NMR (CDCl3, 75 MHz) 189.7, 175.0, 168.0, 158.7, 151.6, 150.5, 141.4, 139.5, 134.9, 131.0, 130.2, 124.2, 122.3, 120.6, 114.1, 83.1, 66.2, 28.4.

1. temperaturewas heated
2. temperatureat reflux for 16 h
3. temperatureThe mixture was cooled
4. concentrationconcentrated in vacuo
5. customChromatography on silica gel (30-60% EtOAc/hexanes) gave
6. washWashing of the mixture with hexane in a filter funnel