Hydrochloric Acid → (2S,4R)-2-(2,4-dioxoimidazolidin-1-yl)methyl-4-hydroxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

A solution of (2S,4R)-4-t-butyldimethylsilyloxy-2-(2,4-dioxoimidazolidin-1-yl)methyl-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (4.78 g) in a mixture of methanol (100 ml) and concentrated hydrochloric acid (1.62 ml) was stirred at ambient temperature for 1 hour. The reaction mixture was evaporated in vacuo. The resulting residue was dissolved in toluene (30 ml) and the solution was concentrated under reduced pressure to give a residue. The residue was chromatographed on silica gel (60 g) eluting with a mixture of dichloromethane and acetone (2:1 V/V). The fractions containing the desired compound were collected and evaporated in vacuo to give (2S,4R)-2-(2,4-dioxoimidazolidin-1-yl)methyl-4-hydroxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (3.27 g).