Reaktion #47509

Reaktionsgleichung

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

N-bromosuccinimide

benzoyl peroxide

→

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

Ausbeute 40.0%

Lösungsmittel

carbon tetrachloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeNitrogen gas was bubbled through the mixture for 5 min
2. 2
   Temperaturthe resulting mixture was heated
3. 3
   Temperaturto reflux for 4 h
4. 4
   Sonstigewas then placed in the refrigerator overnight
5. 5
   SonstigeThe solids formed
6. 6
   Sonstigewere removed by filtration
7. 7
   Einengenthe filtrate concentrated in vacuo
8. 8
   SonstigeThe crude product obtained
9. 9
   Sonstigewas purified

Vorschrift

To a stirred mixture of (E)-3-(2,3-difluoro-phenoxy)-but-2-enoic acid ethyl ester (8.01 g, 0.033 mol) in carbon tetrachloride (30 mL) under a nitrogen atmosphere was added N-bromosuccinimide (8.91 g, 0.050 mol) and benzoyl peroxide (810 mg, 0.003 mol). Nitrogen gas was bubbled through the mixture for 5 min, and the resulting mixture was heated to reflux for 4 h. The reaction mixture was then placed in the refrigerator overnight. The solids formed were removed by filtration and the filtrate concentrated in vacuo. The crude product obtained was purified using flash column chromatography (silica gel (100-200 mesh), ethyl acetate/hexanes) to afford (E)-4-bromo-3-(2,3-difluoro-phenoxy)-but-2-enoic acid ethyl ester (4.20 g, 40%) as a yellow oil.

Quelle