反应详情

A suspension of 29.0 g of 2-bromo-4'-hydroxy-3'-methoxy-5'-nitroacetophenone in 700 ml of dry methylene chloride is treated at -20° within 30 minutes with a solution of 125.3 g of boron tribromide in 300 ml of dry methylene chloride. After the addition the mixture is stirred at -20° for a further 1 hour and at room temperature for 16 hours, then evaporated, the residue is treated cautiously with water while cooling with ice and stirred at 50° for 30 minutes. After cooling the mixture is extracted with ether, the ethereal phase is washed with water, dried over sodium sulfate, filtered and evaporated. There is obtained 2-bromo-3',4'-dihydroxy-5'-nitroacetophenone of m.p. 138°-140° (from methylene chloride).

1. additionAfter the addition the mixture
2. customevaporated
3. additionthe residue is treated cautiously with water
4. temperaturewhile cooling with ice
5. stirringstirred at 50° for 30 minutes
6. temperatureAfter cooling the mixture
7. extractionis extracted with ether
8. washthe ethereal phase is washed with water
9. dry with materialdried over sodium sulfate
10. filtrationfiltered
11. customevaporated