Reaktion #43602

Reaktionsgleichung

1,2-dibromoethane

3-bromo-4,5-dihydroxybenzaldehyde

cesium carbonate

→

desired compound

Ausbeute 75.0%

8-Bromo-2,3-dihydro-1,4-benzodioxin-6-carbaldehyde

Ausbeute 75.0%

Lösungsmittel

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter heating at 80° for 4 h
2. 2
   Sonstigethe dimethylformamide was removed under reduced pressure
3. 3
   SonstigeThe residue was partitioned between water and ethyl acetate
4. 4
   Waschenthe organic layer was washed with brine
5. 5
   Sonstigedried
6. 6
   SonstigeThe crude product was purified by flash column chromatography (silica gel, 4:1 hexane:ethyl acetate)

Vorschrift

To a solution of 3-bromo-4,5-dihydroxybenzaldehyde (11.5 g, 0.52 mol) in dimethylformamide (220 ml) was added cesium carbonate (50.7 g, 1.56 mol). The mixture was stirred at ambient temperature for 30 min, then 1,2-dibromoethane (12.76 g, 0.68 mol) were added. After heating at 80° for 4 h, the dimethylformamide was removed under reduced pressure. The residue was partitioned between water and ethyl acetate, and the organic layer was washed with brine and dried. The crude product was purified by flash column chromatography (silica gel, 4:1 hexane:ethyl acetate) to give the desired compound as an off-white solid (9.57 g, 75%).

Quelle