Реакция #43602

Уравнение реакции

1,2-dibromoethane

3-bromo-4,5-dihydroxybenzaldehyde

cesium carbonate

→

desired compound

Выход 75.0%

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

Выход 75.0%

Растворители

dimethylformamide

Условия реакции

Обработка

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

Методика

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%).

Источник