反应详情

温度

5 °C

Preparation of ##STR8## 7.76 g of the sodium salt of 3-hydroxy-2-(o-tolyl)-acrylic acid methyl ester and 0.3 g of 15-crown-5 in 160 ml of N-methyl-2-pyrrolidone (NMP) are cooled to 5° C. with stirring. Chlorodifluoromethane is then passed in while simultaneously adding dropwise a solution of 8.5 g of sodium hydroxide in 9.3 ml of water and the reaction mixture is left to react with vigorous stirring at 5°-8° C. for 2 hours. 82 ml of 2N hydrochloric acid are then added dropwise at 0°-8° C. and the phases are separated. The aqueous phase is extracted exhaustively with ethyl acetate and the combined organic phases are washed with a saturated sodium chloride solution. After drying over sodium sulfate, the residue is filtered and concentrated to dryness by evaporation in vacuo. 3-difluoromethoxy-2-(o-tolyl)acrylic acid methyl ester is obtained in the form of a pale yellow oil.

1. waitthe reaction mixture is left
2. customto react
3. stirringwith vigorous stirring at 5°-8° C. for 2 hours
4. customthe phases are separated
5. extractionThe aqueous phase is extracted exhaustively with ethyl acetate
6. washthe combined organic phases are washed with a saturated sodium chloride solution
7. dry with materialAfter drying over sodium sulfate
8. filtrationthe residue is filtered
9. concentrationconcentrated to dryness by evaporation in vacuo