反应详情

To a solution of 2-pentanone (1.72 g) in methanol (10 mL) was added bromine (3.20 g) at −30° C. The mixture was allowed to warm to room temperature and stirred until the red color of bromine disappeared. To the obtained colorless solution were added sodium acetate (3.20 g) and N-(2-phenylethyl)thiourea (2.70 g) and the mixture was stirred with heating under reflux for 4 hr. A saturated aqueous sodium hydrogencarbonate solution (10 mL) was added to the reaction mixture and the mixture was concentrated. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:9-2:1 in volume ratio) to give the title compound (850 mg, yield 23%) as pale-yellow crystals.

1. temperaturewith heating
2. temperatureunder reflux for 4 hr
3. concentrationthe mixture was concentrated
4. customThe residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:9-2:1 in volume ratio)