Hydrochloric Acid → (2S,4R)-4-hydroxy-2-(1-methyl-1H-tetrazol-5-yl)thiomethyl-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

To a solution of (2S,4R)-4-t-butyldimethylsilyloxy-2-(1-methyl-1H-tetrazol-5-yl)thiomethyl-1-(4nitrobenzyloxycarbonyl)pyrrolidine (1.67 g) in methanol (30 ml) was added conc. hydrochloric acid (0.82 ml) at ambient temperature. After stirring at the same temperature for 1 hour, the reaction mixture was concentrated under reduced pressure. The resulting residue was dissolved in ethyl acetate (80 ml). 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 (2S,4R)-4-hydroxy-2-(1-methyl-1H-tetrazol-5-yl)thiomethyl-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (1.25 g).