تفاعل #62881

معادلة التفاعل

3-bromo-4-fluorobenzaldehyde

ethylene glycol

→

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

المردود 78.3%

المذيبات

toluene

ظروف التفاعل

المعالجة

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

الإجراء التجريبي

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.

المصدر