反应详情

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.

1. temperaturewas heated at the reflux temperature under a Dean and Stark trap
2. customapproximately 12 cm3 of water had collected in the trap, and analysis of the reaction mixture by gas liquid chromatography
3. washThe mixture was washed with sodium bicarbonate solution and brine
4. dry with materialdried over anhydrous magnesium sulphate
5. customEvaporation of the solvent under reduced pressure
6. customgave a yellow oil, which
7. distillationwas purified by distillation under reduced pressure