反应详情

To a solution of 2-hydroxy-4-trifluoromethyl-benzoic acid (5 g, 24.258 mmol, Matrix Scientific) in ethanol (50 mL) were added potassium carbonate (8.38 g, 60.645 mmol) and ethyl iodide (7.68 mL, 97.032 mmol). The reaction mixture was heated at gentle reflux for 4 h then concentrated in vacuo. The residue was taken in petroleum ether and water, and the layers were separated. The product was extracted with petroleum ether (1×). The organic layers were washed with brine (1×), dried over anhydrous sodium sulfate, filtered and concentrated. Purification of the crude residue by flash chromatography (40 g of silica gel, eluting with 10% ethyl acetate in hexane) gave 2-ethoxy-4-trifluoromethyl-benzoic acid ethyl ester as colorless oil (4.68 g, 74%).

1. temperatureThe reaction mixture was heated
2. temperatureat gentle reflux for 4 h
3. concentrationthen concentrated in vacuo
4. customwater, and the layers were separated
5. extractionThe product was extracted with petroleum ether (1×)
6. washThe organic layers were washed with brine (1×)
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated
10. customPurification of the crude residue
11. washby flash chromatography (40 g of silica gel, eluting with 10% ethyl acetate in hexane)