反应详情

In methanol (30 ml), 2,5-dimethylbenzoic acid (1.772 g) was dissolved. The reaction solution was added with concentrated sulfuric acid (0.7 ml) and the whole was refluxed under heating for 17 hours. After having been cooled to room temperature, the reaction solution was concentrated under reduced pressure. The resultant residue was added with a saturated aqueous sodium hydrogen carbonate solution to make the pH thereof to 9, followed by extraction with chloroform. The organic layer was washed with a saturated saline solution and dried with anhydrous sodium sulfate. After a drying agent was filtrated out, the filtrate was concentrated under reduced pressure. The resultant residue was purified through silica gel column chromatography (hexane/ethyl acetate), thereby obtaining the subject compound (1.9353 g) as a pale-yellow oily substance.

1. temperaturethe whole was refluxed
2. temperatureunder heating for 17 hours
3. concentrationthe reaction solution was concentrated under reduced pressure
4. additionThe resultant residue was added with a saturated aqueous sodium hydrogen carbonate solution
5. extractionto 9, followed by extraction with chloroform
6. washThe organic layer was washed with a saturated saline solution
7. dry with materialdried with anhydrous sodium sulfate
8. filtrationAfter a drying agent was filtrated out
9. concentrationthe filtrate was concentrated under reduced pressure
10. customThe resultant residue was purified through silica gel column chromatography (hexane/ethyl acetate)