O.[OH-].[Li+].OO.C([C@H]1COC(=O)N1[C:19]([C@H:21]1[CH2:25][C:24](=[O:26])[N:23]([CH2:27][C:28]2[CH:33]=[CH:32][C:31]([O:34][CH3:35])=[CH:30][C:29]=2[O:36][CH3:37])[CH2:22]1)=[O:20])C1C=CC=CC=1.S([O-])(O)=[O:39].[Na+]>O.O1CCCC1>[CH3:37][O:36][C:29]1[CH:30]=[C:31]([O:34][CH3:35])[CH:32]=[CH:33][C:28]=1[CH2:27][N:23]1[C:24](=[O:26])[CH2:25][C@H:21]([C:19]([OH:20])=[O:39])[CH2:22]1
To a solution of lithium hydroxide monohydrate (2.0 g) in water (45 ml) was added dropwise 30 wt % aqueous solution of hydrogen peroxide solution (11 ml)) in an ice-sodium chloride cooling bath, and the mixture was stirred for 15 minutes. To this reaction solution was added tetrahydrofuran (36 ml), and then a solution of (S)-4-benzyl-3-[(S)-1-(2,4-dimethoxybenzyl)-5-oxopyrrolidine-3-carbonyl]-2-oxazolidinone (17.2 g) in tetrahydrofuran (144 ml) was added dropwise thereto, and the mixture was stirred for additional 20 minutes. To this reaction solution was slowly added a 10 wt % aqueous solution of sodium hydrogen sulfite (131 ml), and the mixture was stirred at room temperature for 1 hour after removing the bath, and then extracted with ethyl acetate (180 ml). The resulting organic layer was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluent: ethyl acetate to chloroform/methanol=9/1). To the resulting product (6.7 g) was added diisopropyl ether (13.4 ml), the mixture was stirred at 70° C., and then cooled to 0° C. with stirring. A solid was collected from this suspension by filtration, dried under reduced pressure to give the titled compound (5.5 g). An analysis of this solid by HPLC analysis condition 1 showed that an isomer with longer retention time was a main product.
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