反应详情

An excess of 1,5-dibromopentane (100 g, 3 equivalents) was added to a suspension of vanillin (43) (22 g) and potassium carbonate (30 g) in acetone (700 mL). The reaction mixture was heated at reflux for 2.5 hours and then allowed to stir at room temperature overnight, at which time TLC and LC/MS showed the reaction to be complete. The suspension was subjected to vacuum filtration and the resulting acetone solution was evaporated to dryness under reduced pressure. The residue was applied to a pad of silica gel and washed with 10% ethyl acetate in hexane (2 L) followed by 25% ethyl acetate in hexane to elute the product, removal of excess solvent by rotary evaporation under reduced pressure afforded the product 44 as an oil which crystallised on standing in freezer (35 g, 80% yield).

1. temperatureThe reaction mixture was heated
2. temperatureat reflux for 2.5 hours
3. customthe reaction
4. filtrationThe suspension was subjected to vacuum filtration
5. customthe resulting acetone solution was evaporated to dryness under reduced pressure
6. washwashed with 10% ethyl acetate in hexane (2 L)
7. washto elute
8. customthe product, removal of excess solvent
9. customby rotary evaporation under reduced pressure