反应详情

To a stirred solution methyl 3-acetyl-5-bromo-4-hydroxybenzoate (106 g, 388 mmol) in toluene (1 L) was added dropwise (diethyloxonio)trifluoroborate (0.201 L, 1630 mmol), under nitrogen. The resulting solution was left to stir overnight at room temperature, then 4-(dichloromethylene)morpholin-4-ium chloride (143 g, 698 mmol) was added and mixture heated at 90° C. for 12 h. Upon cooling to room temperature, ether (1.5 L) was added and the solid was collected by filtration. This solid was then suspended in MeOH (1 L) and the mixture was heated at 50° C. for 2 h. Upon cooling to room temperature, the solid was collected by filtration then solubilized in DCM (1 L) and washed with water and a saturated solution of sodium bicarbonate. The organic layer was dried over MgSO4, filtered and evaporated to dryness to afford methyl 8-bromo-2-morpholino-4-oxo-4H-chromene-6-carboxylate (68.0 g, 47.6%) as an off-white solid. Mass Spectrum: m/z [M+H]+=368.

1. waitThe resulting solution was left
2. temperaturemixture heated at 90° C. for 12 h
3. temperatureUpon cooling to room temperature
4. filtrationthe solid was collected by filtration
5. temperaturethe mixture was heated at 50° C. for 2 h
6. temperatureUpon cooling to room temperature
7. filtrationthe solid was collected by filtration
8. washwashed with water
9. dry with materialThe organic layer was dried over MgSO4
10. filtrationfiltered
11. customevaporated to dryness