Reaktion #47332

Reaktionsgleichung

3-(3-chloro-2-fluoro-phenoxy)-but-2-enoic acid ethyl ester

N-bromosuccinimide

benzoyl peroxide

→

4-bromo-3-(3-chloro-2-fluoro-phenoxy)-but-2-enoic acid ethyl ester

Ausbeute 86.4%

Lösungsmittel

carbon tetrachloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction was then warmed
2. 2
   Temperaturto reflux for 5 h
3. 3
   SonstigeAt this time, the reaction was removed from the freezer
4. 4
   SonstigeThe resulting precipitate was removed by filtration
5. 5
   EinengenThe filtrate was concentrated in vacuo
6. 6
   SonstigePurification by Analogix flash chromatography (40 g, 1-10% ethyl acetate/hexanes)

Vorschrift

A solution of 3-(3-chloro-2-fluoro-phenoxy)-but-2-enoic acid ethyl ester (1.41 g, 5.45 mmol) in carbon tetrachloride (30 mL) was treated with N-bromosuccinimide (1.07 g, 6.01 mmol) and benzoyl peroxide (0.15 g). The reaction was then warmed to reflux for 5 h. At this time, the reaction was cooled to 25° C. and then placed in the freezer over the weekend. At this time, the reaction was removed from the freezer and allowed to thaw. The resulting precipitate was removed by filtration. The filtrate was concentrated in vacuo. Purification by Analogix flash chromatography (40 g, 1-10% ethyl acetate/hexanes) afforded impure 4-bromo-3-(3-chloro-2-fluoro-phenoxy)-but-2-enoic acid ethyl ester (1.59 g, 86%) as a white solid. The material was used without further purification.

Quelle