反应详情

A mixture of 18.2 g (0.1 mole) of 4-methyl-3-(3-oxobutyl)-maleic acid anhydride and 17.5 g (0.15 mole) of dimethylammonium benzoate in 400 ml of benzene is heated under reflux using a water separator for 42 hours. The benzene is removed in vacuo and the residue that remains is partitioned between methylene chloride and saturated sodium bicarbonate solution. The crude product remaining after drying and after removal of the methylene chloride is chromatographed over silica gel with petroleum ether/ether. Subsequent recrystallisation from ether/petroleum ether yields 6-dimethylamino-3-methylbenzofuran-2(3H)-one having a melting point of from 87° to 89° C.

1. temperatureis heated
2. temperatureunder reflux
3. customfor 42 hours
4. customThe benzene is removed in vacuo
5. customthe residue that remains is partitioned between methylene chloride and saturated sodium bicarbonate solution
6. customafter drying
7. customafter removal of the methylene chloride
8. customis chromatographed over silica gel with petroleum ether/ether
9. customSubsequent recrystallisation from ether/petroleum ether