反应详情

7.5 g of (E)-4-(4-(acetylamino)phenyl)-3-butenoic acid was dissolved in a 1N aqueous solution of potassium hydroxide. The obtained solution was heated under reflux for 4 hours and cooled by allowing to stand. After the pH of the solution had been adjusted to about 3 by the addition of concentrated hydrochloric acid, the resulting solution was concentrated under a reduced pressure, followed by the addition of benzene. The obtained mixture was concentrated and freed from the water by azeotropic distillation to obtain a solid. 300 ml of methanol and 1 ml of concentrated sulfuric acid were added to the solid. The obtained mixture was heated under reflux for 3 hours, cooled by allowing to stand and concentrated under a reduced pressure. An aqueous solution of potassium carbonate was added to the residue and the obtained mixture was extracted with ethyl acetate. The extract was washed with water and a saturated aqueous solution of common salt successively and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified by silica gel column chromatography [solvent: n-hexane/ethyl acetate (2:1)] to obtain 5.38 g of the title compound as a lightly orange-colored oil (yield: 82%).

1. temperatureThe obtained solution was heated
2. temperatureunder reflux for 4 hours
3. temperaturecooled
4. concentrationthe resulting solution was concentrated under a reduced pressure
5. additionfollowed by the addition of benzene
6. concentrationThe obtained mixture was concentrated
7. distillationfreed from the water by azeotropic distillation
8. customto obtain a solid
9. temperatureThe obtained mixture was heated
10. temperatureunder reflux for 3 hours
11. temperaturecooled
12. concentrationconcentrated under a reduced pressure
13. additionAn aqueous solution of potassium carbonate was added to the residue
14. extractionthe obtained mixture was extracted with ethyl acetate
15. washThe extract was washed with water
16. dry with materiala saturated aqueous solution of common salt successively and dried over anhydrous sodium sulfate
17. distillationThe solvent was distilled off
18. customthe residue was purified by silica gel column chromatography [solvent: n-hexane/ethyl acetate (2:1)]