Sulfuric Acid → (2S,4R)-4-methanesulfonyloxy-1(4-nitrobenzyloxycarbonyl)-2-(2-oxoimidazolidin-1-yl)carbonylpyrrolidine

Participants

Reaction Conditions

Reaction Steps

To a mixture of N,N-dimethylformamide (0.6 ml) and tetrahydrofuran (1.2 ml) was added dropwise phosphorus oxychloride (0.58 ml) at -5° C. and the mixture was stirred at 5° C. for 5 minutes. To the mixture was added a solution of (2S,4R)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)proline (2.0 g) in tetrahydrofuran (20 ml) under ice-cooling. The solution was stirred at the same temperature for 30 minutes. To a solution were added ethylene urea (2.22 g) and concentrated sulfuric acid (0.035 ml), and the mixture was stirred at 45°-50° C. for 3 hours. Ethyl acetate (100 ml) and water (40 ml) was poured into the reaction mixture. The organic layer was washed with saturated aqueous sodium chloride, 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 (9:1, 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)carbonylpyrrolidine (1.98 g).

Provenance & Evidence