反应详情

28 ml of a 10% w/v methanolic solution of hydrogen chloride were added dropwise to a solution of 1.42 g of (2R,4S)-4-formyloxy-2-{4-[2-(4-nitrobenzyloxycarbonyl)oxyethyl]-1-piperazinylcarbonyl}-1-(4-nitrobenzyloxycarbonyl)pyrrolidine [prepared as described in step (i) above] in 14 ml of 1,4-dioxane, and the resulting mixture was stirred at room temperature for 1 hour. At the end of this time, the solvent was removed by distillation under reduced pressure, and the resulting residue was mixed with water. The aqueous mixture thus obtained was made alkaline by the addition of a saturated aqueous solution of sodium hydrogencarbonate, and then the mixture was extracted with ethyl acetate. The extract was washed with an aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and the residue was purified by column chromatography through silica gel, using a 9:1 by volume mixture of ethyl acetate and methanol as the eluent to give 1.33 g of the title compound, as a colorless powder.

1. customAt the end of this time, the solvent was removed by distillation under reduced pressure
2. additionthe resulting residue was mixed with water
3. customThe aqueous mixture thus obtained
4. extractionthe mixture was extracted with ethyl acetate
5. washThe extract was washed with an aqueous solution of sodium chloride
6. dry with materialdried over anhydrous magnesium sulfate
7. customThe solvent was removed by distillation under reduced pressure
8. customthe residue was purified by column chromatography through silica gel
9. additionby volume mixture of ethyl acetate and methanol as the eluent