反应详情

A mixture of 4-chlorophenylacetic acid (34 g) and red phosphorus (1.5 g) was stirred under an atmosphere of nitrogen and dry bromine (20 g) was carefully added over a period of 30 minutes. The reaction mixture was heated to a temperature of 100° C. and dry bromine (32 g) was carefully added over a period of 45 minutes. The mixture was then heated under reflux for 3 hours and cooled. Ethyl alcohol (100 ml) was added to the reaction mixture and the mixture allowed to stand overnight. The ethanolic mixture was diluted with water and extracted with ethylene dichloride. The extract was washed with aqueous sodium carbonate, dried over anhydrous sodium sulfate and the solvent removed by distillation under reduced pressure. The product was distilled through a Fenske ring column to give ethyl α-bromo-4-chlorophenylacetate (33.4 g; 65%) b.p. 119° C. at 0.9 mm of Hg.

1. additionwas carefully added over a period of 45 minutes
2. temperatureThe mixture was then heated
3. temperatureunder reflux for 3 hours
4. temperaturecooled
5. extractionextracted with ethylene dichloride
6. washThe extract was washed with aqueous sodium carbonate
7. dry with materialdried over anhydrous sodium sulfate
8. customthe solvent removed by distillation under reduced pressure
9. distillationThe product was distilled through a Fenske ring column