反应详情

88.4 g (311 mmol) of the 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-one obtained in the above step (5) was dissolved in 200 ml of ethanol, and further dissolved in 200 ml of dichloromethane. This solution was cooled to 5°~10° C., and 5.9 g (155 mmol) of sodium borohydride was added. The reaction mixture was stirred at the above temperature for 30 minutes, and further stirred at room temperature for 3 hours. Then, the reaction mixture was poured into 400 ml of a 5% hydrochloric acid aqueous solution and extracted with 900 ml of dichloromethane, and then the resultant organic layer was washed with a saturated sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was distilled off to give 86.8 g (yield 97%) of 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-ol.

1. temperatureThis solution was cooled to 5°~10° C.
2. stirringfurther stirred at room temperature for 3 hours
3. extractionextracted with 900 ml of dichloromethane
4. washthe resultant organic layer was washed with a saturated sodium chloride aqueous solution
5. dry with materialdried over anhydrous sodium sulfate
6. distillationThe solvent was distilled off