반응 #360857

반응 방정식

4-(2-Bromoethyl)phenyl boronic acid

2-nitroimidazole

potassium carbonate

→

bromide

수율 14.1%

4-(2 -Nitroimidazolyl ethyl)phenyl boronic acid

수율 14.1%

용매

dimethylformamide

반응 조건

후처리

1. 1
   기타Dimethylformamide was removed under reduced pressure
2. 2
   workup.DISSOLUTIONthe resulting gum was dissolved in a minimum amount of water
3. 3
   여과The precipitated solid was filtered off
4. 4
   세척washed with water
5. 5
   추출The combined aqueous portion was again extracted with ethyl acetate (5×50 ml)
6. 6
   기타The organic layer was dried
7. 7
   농축concentrated
8. 8
   기타chromatographed (silica gel)
9. 9
   세척Elution with 1:1 ethyl acetate/hexane

실험 절차

4-(2-Bromoethyl)phenyl boronic acid (0.525 g, 2.72 mmol) and 2-nitroimidazole (0.3 g, 2.72 mmol) were heated in dry dimethylformamide (15 ml) in presence of anhydrous potassium carbonate (1.38 g, 10 mmol) under nitrogen with stirring at 60°-70° C. for 48 hours. Dimethylformamide was removed under reduced pressure and the resulting gum was dissolved in a minimum amount of water and acidified with 2N hydrochloric acid. The precipitated solid was filtered off and washed with water. The combined aqueous portion was again extracted with ethyl acetate (5×50 ml). The organic layer was dried, concentrated and combined with the previously precipitated solid and chromatographed (silica gel). Elution with 1:1 ethyl acetate/hexane yielded some unreacted starting bromide (0.1 g); continued elution with 2:1 ethyl acetate/hexane provided the required boronic acid as a pale yellow crystalline solid. The product was recrystallized from tetrahydrofuran/hexane. Yield: 0.25 g (36%), m.p. 229°-231° C., M.S. (M+H)+ 262.

출처