反应详情

To a solution of ethyl 4-oxo-4H-quinolizine-3-carboxylate (1) (2.33 g, 10.7 mmol) in 20 ml acetic acid was rapidly added a solution of bromine (1.9 g, 12 mmol) in 10 ml acetic acid. The reaction was complete after 5 min, as indicated by thin layer chromatography (ethyl acetate). The solvent was evaporated in vacuo and the remaining yellow solid was dissolved in 20 ml dichloromethane. To this solution, silica gel (3 g) was added and the solvent was evaporated in vacuo. The silica gel was poured on a prepacked column and eluted with ethyl acetate to give ethyl 1-bromo-4-oxo-4H-quinolizine-3-carboxylate (9) as a bright yellow solid (2.1 g, 71%). M.p. 156-158° C. 1H NMR (δ, CDCl3): 1.43 (t, J=7 Hz, 3H), 4.43 (q, J=7 Hz, 2H), 7.03 (dd, J=7 Hz, J=7 Hz, 1H), 7.30 (dd, J=7 Hz, 2H), 7.80 (dd, J=7 Hz, J=7 Hz, 1H), 8.63 (s, 1H), 9.49 (d, J=7 Hz). MS: m/z 294.9839; required for C12H10BrNO3: 294.9843.

1. customThe solvent was evaporated in vacuo
2. dissolutionthe remaining yellow solid was dissolved in 20 ml dichloromethane
3. additionTo this solution, silica gel (3 g) was added
4. customthe solvent was evaporated in vacuo
5. additionThe silica gel was poured on a prepacked column
6. washeluted with ethyl acetate