反应详情

To a suspension of ethyl 4-oxo-4H-quinolizine-3-carboxylate (1) (100 mg, 0.46 mmol) in 4 ml methanol was added 300 μl NaOH (3 M). The reaction mixture was stirred overnight, followed by evaporation of the solvent in vacuo. The remaining solid was dissolved in 4 ml water and the clear solution was acidified to pH 1, with 1 M HCl. The resulting suspension was filtered, and the residue was dried in vacuo over P2O5 to give yellow plates of 4-oxo-4H-quinolizine-3-carboxylic acid (1a) (63 mg, 72%). M.p. 235-240° C. 1H NMR (δ, DMSO-d6): 7.26 (d, J=8 Hz, 1H), 7.64 (dd, J=7 Hz, J=7 Hz, 1H), 8.03 (dd, J=7 Hz, J=7 Hz, 1H), 8.14 (d, J=9 Hz, 1H), 8.39 (d, J=9 Hz, 1H), 9.27 (d, J=7 Hz), 14.13 (s, 1H). MS: m/z 189.0433; required for C12H11NO3: 189.0428.

1. customfollowed by evaporation of the solvent in vacuo
2. dissolutionThe remaining solid was dissolved in 4 ml water
3. filtrationThe resulting suspension was filtered
4. dry with materialthe residue was dried in vacuo over P2O5