反应详情

温度

-10 °C

Nitric acid (1.08 g, 17 mmol) was added slowly to acetic anhydride (7 mL) at 5° C. Stirring was continued for 5 min and the reaction mixture was cooled to −10° C. (ice/salt bath). Ethyl 4-oxo-4H-quinolizine-3-carboxylate (1) (920 mg, 4.2 mmol) was added in one portion. After 5 min, an orange precipitate formed. The reaction was complete after 15 min as indicated by thin layer chromatography (ethyl acetate). The reaction mixture was poured into 250 g crushed ice and stirred for 30 min to give an orange suspension, which was extracted three times with 100 mL dichloromethane. The combined organic layers were washed three times with 100 ml water. Evaporation of the solvent gave a deep red solid. Purification by flash chromatography gave a bright yellow solid (497 mg, 50% yield). M.p. 169-170° C. 1H NMR (δ, CDCl3): 1.44 (t, J=7.0 Hz, 3H), 4.45 (q, J=7.0 Hz, 2H), 7.55 (dd, J=7.0 Hz, J=7.0 Hz, 1H), 8.15 (dd, J=9.7 Hz, 7.0 Hz, 1H), 9.31 (d, J=9.1 Hz, 1H), 9.47 (s, 1H), 9.60 (d, J=7.0 Hz, 1H). MS: m/z 262.0601; required for C12H10N2O5: 262.0590.

1. waitAfter 5 min
2. customan orange precipitate formed
3. waitThe reaction was complete after 15 min
4. additionThe reaction mixture was poured into 250 g
5. customcrushed ice
6. stirringstirred for 30 min
7. customto give an orange suspension, which
8. extractionwas extracted three times with 100 mL dichloromethane
9. washThe combined organic layers were washed three times with 100 ml water
10. customEvaporation of the solvent
11. customgave a deep red solid
12. customPurification by flash chromatography