反应详情

To a solution of the secondary benzazepine (0.98 g, 3.9 mmol) from step E above in dichloromethane (50 mL) were added acetaldehyde (0.44 mL, 7.7 mmol), sodium triacetoxyborohydride (1.8 g, 8.3 mmol), acetic acid (0.2 mL), and 3 Å molecular sieves (1.0 g). The reaction solution was stirred at room temperature for 24 h and then it was diluted with dichloromethane, washed with aqueous 1 N sodium carbonate, dried over sodium sulfate and concentrated in vacuo. The crude product obtained was purified by flash column chromatography (dichloromethane to 95:4.5:0.5 dichloromethane/methanol/concentrated ammonium hydroxide) to give the desired N-ethyl benzazepine (0.53 g, 48%) as a yellow oil: 1H NMR (CDCl3, 500 MHz) δ 7.34 (t, J=7.5 Hz, 2H), 7.25 (t, J=7.5 Hz, 1H), 7.17 (d, J=7.5 Hz, 2H), 6.75 J=2.5 Hz, 1H), 6.68-6.40 (br, 2H), 4.27 (d, J=8.5 Hz, 1H), 3.94 (d, J=13.5 Hz, 1H), 3.81 (d, J=14.5 Hz, 1H), 3.77 (s, 3H), 3.27-3.16 (br, 1H), 3.06-3.01 (m, 1H), 2.55-2.45 (m, 2H), 2.32-2.24 (m, 1H), 2.13-2.04 (br, 1H), 1.11 (t, J=7.0 Hz, 3H); ESI MS m/z 282 [M+H]+.

1. washwashed with aqueous 1 N sodium carbonate
2. dry with materialdried over sodium sulfate
3. concentrationconcentrated in vacuo
4. customThe crude product obtained
5. customwas purified by flash column chromatography (dichloromethane to 95:4.5:0.5 dichloromethane/methanol/concentrated ammonium hydroxide)