反应详情

To a mixture of 65.2 ml of n-butyllithium (1.61M in hexane) and 100 ml of anhydrous ether was added dropwise 29.3 g of 4-bromo-3,5-dichlorobenzotrifluoride (3) in 30 ml of anhydrous ether at -78° C., followed by stirring for 20 minutes. Subsequently, 10 g of dry ice crashed into small pieces was added in small portions to the reaction mixture, followed by stirring at room temperature for 1.5 hours. Ice water was added to the reaction mixture, the mixture was thereafter extracted with ether, and the combined extract was subjected to reverse extraction with 10% aqueous sodium carbonate solution. The aqueous layer was acidified with 6N hydrochloric acid, followed by extraction with ethyl acetate, washing with brine and drying over anhydrous magnesium sulfate. Removal of the solvent under reduced pressure gave 20.4 g of the desired product in the form of white crystals (crude yield 79.1%). mp 117°~118° C.

1. additionwas added in small portions to the reaction mixture
2. stirringby stirring at room temperature for 1.5 hours
3. extractionthe mixture was thereafter extracted with ether
4. extractionthe combined extract
5. extractionextraction with 10% aqueous sodium carbonate solution
6. extractionfollowed by extraction with ethyl acetate
7. washwashing with brine
8. dry with materialdrying over anhydrous magnesium sulfate
9. customRemoval of the solvent under reduced pressure