Réaction #62880

Équation de réaction

4-fluorobenzaldehyde

aluminium trichloride

Bromine

→

3-bromo-4-fluorobenzaldehyde

Rendement 56.3%

Solvants

dichloromethane

dichloromethane

Conditions de réaction

Traitement

1. 1
   Températurea cooled
2. 2
   Températurethe mixture heated at the reflux temperature of 16 hours
3. 3
   TempératureAfter cooling
4. 4
   workup.ADDITIONthe reaction mixture was carefully poured onto ice
5. 5
   Extractionextracted with dichloromethane
6. 6
   LavageThe combined organic layers were washed with saturated sodium metabisulphite solution, water and brine
7. 7
   Séchagedried over anhydrous magnesium sulphate
8. 8
   AutreEvaporation of the solvent under reduced pressure
9. 9
   Autregave a dark red oil, which
10. 10
    workup.DISTILLATIONwas purified by distillation under reduced pressure

Mode opératoire

A solution of 4-fluorobenzaldehyde (49.6 g) in dry dichloromethane (20 cm3) was added to a cooled (0° C.) suspension of powdered aluminium trichloride (90.4 g) in dry dichloromethane (100 cm3). Bromine (70.4 g) was added, and the mixture heated at the reflux temperature of 16 hours. After cooling, the reaction mixture was carefully poured onto ice and extracted with dichloromethane. The combined organic layers were washed with saturated sodium metabisulphite solution, water and brine, then dried over anhydrous magnesium sulphate. Evaporation of the solvent under reduced pressure gave a dark red oil, which was purified by distillation under reduced pressure, using a 4" Vigreux column to give 3-bromo-4-fluorobenzaldehyde (45.7 g) as an oil, boiling point 85°-108° C. at 8 mmHg.

Source