Reaktion #47357

Reaktionsgleichung

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

Ausbeute 87.2%

Lösungsmittel

carbon tetrachloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction was then heated
2. 2
   TemperaturAt this time, the reaction was cooled to 25° C.
3. 3
   Sonstigewas placed in the refrigerator overnight
4. 4
   SonstigeAt this time, the reaction was removed from the refrigerator
5. 5
   SonstigeThe resulting precipitate was removed by filtration
6. 6
   Waschenwas rinsed with carbon tetrachloride (25 mL)
7. 7
   EinengenThe filtrate was concentrated in vacuo
8. 8
   SonstigePurification by Analogix flash chromatography (40 g, 2% ethyl acetate/hexanes)

Vorschrift

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.

Quelle