Acetic Acid → N-Benzylcytisine

Beteiligte Stoffe

Reaktionsschritte

To a 25 ml round bottom flask was added 0.510 gm (2.68 mmol) cytisine in 10 ml of 1,2-dichloroethane. The above solution was treated with 0.272 ml (2.68 mmol) benzaldehyde, 153 μl acetic acid and 0.852 gm (4.02 mmol) sodium triacetoxyborohydride. The reaction mixture was stirred at room temperature for 2 hours and was then partitioned between methylene chloride and 1 N HCl (aq). The organic phase was washed with brine, dried and the solvent evaporated in vacuo to a solid. Chromatography on silica gel eluting with 1% methanol in methylene chloride afforded 434 mg (58%) of the title product which was used in the next step. 1H NMR (CDCl3, 250 MHz) δ 7.28 (dd, 1H), 7.15 (m, 3H), 6.98 (m, 2H), 6.98 (m, 2H), 6.52 (d, 1H), 5.92 (d, 1H), 4.10 (d, 1H), 3.88 (dd, 1H), 3.40 (dd, 2H), 2.88 (m, 3H), 2.39 (br.s, 1H), 2.3 (dd, 2H), 1.82 (dd, 2H) ppm.

Herkunft & Nachweise