反应详情

To a solution of sodium borohydride (0.32 g) in tetrahydrofuran (20 ml) was added dropwise boron trifluoride etherate (6.0 ml) under ice-cooling and the mixture was stirred at the same temperature for 10 minutes. To the mixture was added a solution of (2S,4R)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)- 2-(2-oxoimidazolidin-1-yl)carbonylpyrrolidine (2.0 g) in tetrahydrofuran (10 ml) and the mixture was stirred at ambient temperature for 3 hours. To a reaction mixture was added dropwise methanol (30 ml) under ice-cooling and the solution was evaporated in vacuo. The resulting residue was dissolved in methanol (30 ml) and conc. hydrochloric acid (0.5 ml) and stirred overnight at ambient temperature. The reaction mixture was evaporated in vacuo to give a residue. The residue was dissolved in a mixture of ethyl acetate (60 ml) and tetrahydrofuran (30 ml) and the solution was washed with saturated aqueous sodium hydrogen carbonate and saturated aqueous sodium chloride successively, dried over anhydrous magnesium sulfate and evaporated in vacuo to give a residue. The residue was chromatographed on silica gel (100 g) eluting with a mixture of chloroform and methanol (19:1 V/V). The fractions containing the desired compound were collected and evaporated in vacuo to give (2S,4R)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)-2-(2-oxoimidazolidin-1-yl)methylpyrrolidine (0.81 g).

1. temperaturecooling
2. stirringthe mixture was stirred at ambient temperature for 3 hours
3. temperaturecooling
4. customthe solution was evaporated in vacuo
5. dissolutionThe resulting residue was dissolved in methanol (30 ml)
6. stirringconc. hydrochloric acid (0.5 ml) and stirred overnight at ambient temperature
7. customThe reaction mixture was evaporated in vacuo
8. customto give a residue
9. washthe solution was washed with saturated aqueous sodium hydrogen carbonate and saturated aqueous sodium chloride successively
10. dry with materialdried over anhydrous magnesium sulfate
11. customevaporated in vacuo
12. customto give a residue
13. customThe residue was chromatographed on silica gel (100 g)
14. washeluting with a mixture of chloroform and methanol (19:1 V/V)
15. additionThe fractions containing the desired compound
16. customwere collected
17. customevaporated in vacuo