Reaktion #62881

Reaktionsgleichung

3-bromo-4-fluorobenzaldehyde

ethylene glycol

→

2-(3-bromo-4-fluorophenyl)-1,3-dioxolane

Ausbeute 78.3%

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas heated at the reflux temperature under a Dean and Stark trap
2. 2
   Sonstigeapproximately 12 cm3 of water had collected in the trap, and analysis of the reaction mixture by gas liquid chromatography
3. 3
   WaschenThe mixture was washed with sodium bicarbonate solution and brine
4. 4
   Trocknendried over anhydrous magnesium sulphate
5. 5
   SonstigeEvaporation of the solvent under reduced pressure
6. 6
   Sonstigegave a yellow oil, which
7. 7
   workup.DISTILLATIONwas purified by distillation under reduced pressure

Vorschrift

A mixture of 3-bromo-4-fluorobenzaldehyde (45.7 g), ethylene glycol (27.39 g), p-toluenesulphonic acid (0.225 g) and dry toluene (110 cm3) was heated at the reflux temperature under a Dean and Stark trap. After 4.5 hours, approximately 12 cm3 of water had collected in the trap, and analysis of the reaction mixture by gas liquid chromatography indicated that no starting aldehyde was present. The mixture was washed with sodium bicarbonate solution and brine, and dried over anhydrous magnesium sulphate. Evaporation of the solvent under reduced pressure gave a yellow oil, which was purified by distillation under reduced pressure to give 2-(3-bromo-4-fluorophenyl)-1,3-dioxolane (43.56 g), boiling point 68°-106° C. at 0.04 mmHg.

Quelle