[NH2:1][CH2:2][CH2:3][O:4][CH2:5][C@@H:6]1[CH2:10][C@@H:9]([OH:11])[CH2:8][N:7]1[C:12]([O:14][CH2:15][C:16]1[CH:21]=[CH:20][C:19]([N+:22]([O-:24])=[O:23])=[CH:18][CH:17]=1)=[O:13].[N+:25]([C:28]1[CH:38]=[CH:37][C:31]([CH2:32][O:33][C:34](Cl)=[O:35])=[CH:30][CH:29]=1)([O-:27])=[O:26].[OH-].[Na+]>O.O1CCCC1>[OH:11][C@H:9]1[CH2:8][N:7]([C:12]([O:14][CH2:15][C:16]2[CH:17]=[CH:18][C:19]([N+:22]([O-:24])=[O:23])=[CH:20][CH:21]=2)=[O:13])[C@H:6]([CH2:5][O:4][CH2:3][CH2:2][NH:1][C:34]([O:33][CH2:32][C:31]2[CH:30]=[CH:29][C:28]([N+:25]([O-:27])=[O:26])=[CH:38][CH:37]=2)=[O:35])[CH2:10]1To a solution of (2S,4R)-2-(2-aminoethyloxymethyl)-4-hydroxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (1.12 g) in a mixture of water (20 ml) and tetrahydrofuran (40 ml) was added a solution of 4-nitrobenzyloxycarbonyl chloride (0.85 g) in tetrahydrofuran (4 ml) under ice-cooling with stirring, keeping the pH between 8.5-9.5 with 4N aqueous sodium hydroxide. The mixture was stirred at the same condition for 2 hours. The reaction mixture was evaporated under reduced pressure and then ethyl acetate (50 ml) was added thereto. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (20 g) and eluted with a mixture of methanol and chloroform (2:98 V/V) to give (2S,4R)-4-hydroxy-1-(4-nitrobenzyloxycarbonyl)-2-[2-(4nitrobenzyloxycarbonylamino)ethyloxymethyl]pyrrolidine (0.88 g).
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