反应详情

To a solution of 4-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propoxy]-3-bromobenzoic acid (903 mg) in dichloromethane (100 ml) was added conc. sulfuric acid (five drops), and then into the mixture was bubbled isobutene under ice-cooling for 30 minutes. The mixture was left standing at room temperature for 2 days in a sealed vessel. To the reaction mixture was added sodium hydrogen carbonate, and then was bubbled nitrogen gas to remove isobutene. The insolubles were removed by filtration, and the filtrate was subjected to concentration under reduced pressure. The residue was dissolved in ethyl acetate, the solution was washed with a saturated aqueous solution of sodium hydrogen carbonate, and dried with magnesium sulfate. The solvent was removed by evaporation under reduced pressure and the residue was subjected to purification with silica gel flash chromatography [hexane-ethyl acetate (9:1)]. The eluate was concentrated under reduced pressure to give tertbutyl 4-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propoxy]-3-bromobenzoate (660 mg) as slightly brown oily product.

1. custominto the mixture was bubbled isobutene under ice-
2. temperaturecooling for 30 minutes
3. waitThe mixture was left
4. additionTo the reaction mixture was added sodium hydrogen carbonate
5. customwas bubbled nitrogen gas
6. customto remove isobutene
7. customThe insolubles were removed by filtration
8. concentrationthe filtrate was subjected to concentration under reduced pressure
9. dissolutionThe residue was dissolved in ethyl acetate
10. washthe solution was washed with a saturated aqueous solution of sodium hydrogen carbonate
11. dry with materialdried with magnesium sulfate
12. customThe solvent was removed by evaporation under reduced pressure
13. customthe residue was subjected to purification with silica gel flash chromatography [hexane-ethyl acetate (9:1)]
14. concentrationThe eluate was concentrated under reduced pressure