反应详情

To a solution of 4-nitrobenzyl (2R,5R,6S)-6-[(1R)-1- (4-nitrobenzyloxycarbonyloxy)ethyl]-3,7-dioxo-1-azabicyclo[3.2.0]heptane-2-carboxylate (1.92 g) in dichloromethane (50 ml) were added N,N-diisopropyl-N-ethylamine (0.76 ml) and trifluoromethanesulfonic anhydride (0.73 ml) at -30° C., and the solution was stirred at the same temperature for 30 minutes. To this solution was added (2S, 4S)-2-(2-aminothiazol-4-yl)-4-mercapto-1- (4-nitrobenzyloxycarbonyl)pyrrolidine (1.13 g) in dichloromethane (20 ml) at -30° C. and the solution was stirred at 0° C. for 3 hours. The mixture was washed in turn with water and brine, dried over magnesium sulfate, and evaporated in vacuo. The oily residue was chromatographed on silica gel (60 g) eluting with a mixture of dichloromethane and acetone (5:1 V/V) to give 4-nitrobenzyl (5R,6S)-3-[(2S,4S)-2-(2-aminothiazol-4-yl) -1-(4-nitrobenzyloxycarbonyl)pyrrolidin-4-ylthio]-6-[(1R)-1-(4-nitrobenzyloxycarbonyloxy) ethyl]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate (1.85 g).

1. stirringthe solution was stirred at 0° C. for 3 hours
2. washThe mixture was washed in turn with water and brine
3. dry with materialdried over magnesium sulfate
4. customevaporated in vacuo
5. customThe oily residue was chromatographed on silica gel (60 g)
6. washeluting with a mixture of dichloromethane and acetone (5:1 V/V)