Reaktion #66657

Reaktionsgleichung

1,2 dibromoethane

3-bromo-4,5-dihydroxy-benzaldehyde

K2CO3

water

1,2-dibromoethane

→

8-bromo-2,3-dihydro-benzo[1,4]dioxine-6-carboxaldehyde

Ausbeute 99.0%

Lösungsmittel

DMF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with ethyl acetate
2. 2
   WaschenThe combined organics were washed with brine
3. 3
   Trocknendried over Na2SO4
4. 4
   Filtrationfiltered
5. 5
   Einengenconcentrated in vacuo
6. 6
   SonstigeThe crude solid was purified via flash chromatography (9:1 hexane/ethyl acetate)

Vorschrift

To a solution of 3-bromo-4,5-dihydroxy-benzaldehyde (20.78 g, 95 mmol) in 480 ml DMF was added K2CO3 (52.95 g, 383 mmol) followed by 1,2-dibromoethane (8.7 ml, 101 mmol). The mixture was warmed to 100° C. After 18 additional 1,2 dibromoethane (1.0 mL) was added. After 2 h the mixture was poured into water and extracted with ethyl acetate. The combined organics were washed with brine, dried over Na2SO4, filtered and concentrated in vacuo. The crude solid was purified via flash chromatography (9:1 hexane/ethyl acetate) to give 8-bromo-2,3-dihydro-benzo[1,4]dioxine-6-carboxaldehyde (15.82 g, 99%) as a white solid.

Quelle