反应详情

47.7 Grams (157 mmol) of 3-(2-chloro-4-ethoxycarbonyl-5-methylphenylthio)propionic acid was added to 167 g of 20 wt % P2O5 -containing polyphosphoric acid heated at 80~85° C., and then the mixture was stirred under heat for 1 hour and 20 minutes. After allowed to cool to room temperature, the reaction mixture was gradually added to a mixture of 191 g (1.80 mol) of sodium carbonate and ice, and the mixture was stirred at room temperature until the sodium carbonate was almost dissolved. The mixture was extracted with ethyl acetate twice, and the extract was washed with a sodium carbonate aqueous solution twice, with water twice and with a saturated sodium chloride aqueous solution once, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to give 41.3 g (yield 85%) of 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-one.

1. temperatureheated at 80~85° C.
2. temperatureunder heat for 1 hour and 20 minutes
3. dissolutionwas almost dissolved
4. extractionThe mixture was extracted with ethyl acetate twice
5. washthe extract was washed with a sodium carbonate aqueous solution twice
6. dry with materialwith water twice and with a saturated sodium chloride aqueous solution once, and dried over anhydrous sodium sulfate
7. distillationThe solvent was distilled off under reduced pressure