反应详情

25.6 g of triethylamine (253 mmol) and 28.6 g of O-nitrobenzenesulfonyl chloride (129 mmol) were added to a solution of (3R,5S)-5-[(S)-1-amino-2-hydroxyethyl]-3-ethyldihydrofuran-2-one hydrochloride obtained in the above reaction in a mixed solvent of tetrahydrofuran (350 ml) and water (35.0 ml) at 0° C., and the mixture was stirred at the same temperature for two hours. The reaction mixture was concentrated under reduced pressure and 500 ml of water was added, followed by extraction with ethyl acetate. Then, the organic layer was washed with water, a saturated sodium bicarbonate aqueous solution and brine and dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (elution solvent:ethyl acetate). Further, 20 ml of diisopropyl ether and 40 ml of ethyl acetate were added, and the precipitated solid was collected by filtration to obtain 17.0 g of the title compound (total yield over two steps: 59%).

1. concentrationThe reaction mixture was concentrated under reduced pressure and 500 ml of water
2. additionwas added
3. extractionfollowed by extraction with ethyl acetate
4. washThen, the organic layer was washed with water
5. dry with materiala saturated sodium bicarbonate aqueous solution and brine and dried over anhydrous magnesium sulfate
6. filtrationAfter filtration
7. customthe solvent was evaporated under reduced pressure
8. customthe residue was purified by silica gel column chromatography (elution solvent:ethyl acetate)
9. additionFurther, 20 ml of diisopropyl ether and 40 ml of ethyl acetate were added
10. filtrationthe precipitated solid was collected by filtration