反应详情

Ethyl 7-hydroxy-4-oxo-8-n-propyl-4H-1-benzopyran-2-carboxylate (1 g) in anhydrous dimethylformamide (4 ml) is cooled to 0° and treated under nitrogen with sodium hydride (50% dispersion in mineral oil, 180 mg) with stirring for 30 minutes. Dimethylaminothiocarbamylchloride (465 mg) is added and the mixture is stirred 15 minutes at 0°, warmed to 80° and maintained as such for 18 hours. The mixture is cooled, diluted with methylene chloride (50 ml) and washed with water (3×100 ml)), dried over sodium sulfate and reduced to dryness in vacuo. The residue is recrystallized from ethyl acetate and hexane to yield the title compound.

1. stirringthe mixture is stirred 15 minutes at 0°
2. temperaturewarmed to 80°
3. temperaturemaintained as such for 18 hours
4. temperatureThe mixture is cooled
5. washwashed with water (3×100 ml)),
6. dry with materialdried over sodium sulfate
7. customThe residue is recrystallized from ethyl acetate and hexane