Reacción #47357

Ecuación de reacción

3-(2,5-difluoro-phenoxy)-but-2-enoic acid ethyl ester

N-bromosuccinimide

→

4-bromo-3-(2,5-difluoro-phenoxy)-but-2-enoic acid ethyl ester

Rendimiento 87.2%

Disolventes

carbon tetrachloride

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe reaction was then heated
2. 2
   TemperaturaAt this time, the reaction was cooled to 25° C.
3. 3
   Otrowas placed in the refrigerator overnight
4. 4
   OtroAt this time, the reaction was removed from the refrigerator
5. 5
   OtroThe resulting precipitate was removed by filtration
6. 6
   Lavadowas rinsed with carbon tetrachloride (25 mL)
7. 7
   ConcentraciónThe filtrate was concentrated in vacuo
8. 8
   OtroPurification by Analogix flash chromatography (40 g, 2% ethyl acetate/hexanes)

Procedimiento

A solution of 3-(2,5-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 (25 mL). The filtrate was concentrated in vacuo. Purification by Analogix flash chromatography (40 g, 2% ethyl acetate/hexanes) afforded impure 4-bromo-3-(2,5-difluoro-phenoxy)-but-2-enoic acid ethyl ester (1.56 g, 87%) as a clear oil. The material was used without further purification.

Fuente