反应详情

温度

105 °C

A solution of 3-(2,4-difluoro-phenoxy)-but-2-enoic acid ethyl ester (1.35 g, 5.57 mmol) in carbon tetrachloride (30.9 mL) was treated with N-bromosuccinimide (1.09 g, 6.13 mmol) and benzoyl peroxide (108 mg, 0.44 mmol). The reaction was then heated to reflux (105° C.) for 5 h. At this time, the reaction was cooled to 25° C. and then was placed in the refrigerator overnight. At this time, the reaction was removed from the refrigerator. The resulting precipitate was removed by filtration and was rinsed with carbon tetrachloride (10 mL). The filtrate was concentrated in vacuo. Purification by Analogix flash chromatography (40 g, 2% ethyl acetate/hexanes) afforded impure 4-bromo-3-(2,4-difluoro-phenoxy)-but-2-enoic acid ethyl ester (1.45 g, 81%) as a clear oil. The material was used without further purification.

1. temperatureThe reaction was then heated
2. temperatureAt this time, the reaction was cooled to 25° C.
3. customwas placed in the refrigerator overnight
4. customAt this time, the reaction was removed from the refrigerator
5. customThe resulting precipitate was removed by filtration
6. washwas rinsed with carbon tetrachloride (10 mL)
7. concentrationThe filtrate was concentrated in vacuo
8. customPurification by Analogix flash chromatography (40 g, 2% ethyl acetate/hexanes)