反应详情

温度

0 °C

A suspension of ethyl 4-hydroxy-7-methoxy-8-methylquinoline-3-carboxylate (11, 9.2 g, 35.2 mmol) in 5N NaOH (150 mL) was refluxed for 1.5 h (until a clear solution was obtained). Then, the solution was cooled to 0° C. and the pH adjusted to 2-3 with concentrated HCl. The solid was filtered off and successively washed with water, acetone and ether. This powder was added in small portions to diphenylether (40 mL), pre-heated at 250° C. The resulting suspension became a solution after 20 min (CO2 formation was observed). After 1 h at 250° C., the brown solution was cooled to room temperature and diluted with heptanes (200 mL). The precipitate was filtered off and washed with heptanes and ether to give 6.4 g (96%) of the target product 12 as a yellow powder: m/z=190 (M+H)+.

1. temperaturewas refluxed for 1.5 h (until a clear solution
2. customwas obtained)
3. filtrationThe solid was filtered off
4. washsuccessively washed with water, acetone and ether
5. additionThis powder was added in small portions to diphenylether (40 mL)
6. temperaturepre-heated at 250° C
7. customafter 20 min
8. temperaturethe brown solution was cooled to room temperature
9. additiondiluted with heptanes (200 mL)
10. filtrationThe precipitate was filtered off
11. washwashed with heptanes and ether