反应详情

40 ml of a 10% w/v methanolic solution of hydrogen chloride were added to a solution of 1.0 g of (2S,4S)-4-acetylthio-2-(4-[2-(4-nitrobenzyloxycarbonyl)oxyethyl]-1-piperazinylcarbonyl)-1-(4-nitrobenzyloxycarbonyl)-pyrrolidine [prepared as described in step (ii) above] in 10 ml of 1,4-dioxane, and the resulting mixture was stirred at 50° C. to 52° C. for 1 hour. At the end of this time, the reaction mixture was concentrated by evaporation under reduced pressure, and the concentrate was diluted with 100 ml of ethyl acetate. The dilute solution was neutralized with a saturated aqueous solution of sodium hydrogencarbonate and washed, in turn, with 30 ml of water and with 30 ml of an aqueous solution of sodium chloride. The solvent was removed by distillation under reduced pressure, and the resulting residue was purified by colorful chromatography through silica gel, using a 20:1 by volume mixture of ethyl acetate and methanol as the eluent, to give 566 mg of the title compound, as a colorless powder.

1. concentrationAt the end of this time, the reaction mixture was concentrated by evaporation under reduced pressure
2. additionthe concentrate was diluted with 100 ml of ethyl acetate
3. washwashed, in turn, with 30 ml of water and with 30 ml of an aqueous solution of sodium chloride
4. customThe solvent was removed by distillation under reduced pressure
5. customthe resulting residue was purified by colorful chromatography through silica gel
6. additionby volume mixture of ethyl acetate and methanol as the eluent