C([O:3][C:4](=O)[C@H:5]1[CH2:9][CH:8]([OH:10])[CH2:7][N:6]1[S:11]([C:14]1[CH:19]=[CH:18][C:17]([CH3:20])=[CH:16][CH:15]=1)(=[O:13])=[O:12])C.[BH4-].[Li+].Cl>O1CCCC1>[OH:10][CH:8]1[CH2:7][N:6]([S:11]([C:14]2[CH:19]=[CH:18][C:17]([CH3:20])=[CH:16][CH:15]=2)(=[O:13])=[O:12])[C@@H:5]([CH2:4][OH:3])[CH2:9]1To an ice-cold solution of 286.4 g (0.914 mole) of 4-hydroxy-(4-toluenesulfonyl)-D-proline ethyl ester (5) in 2.8 L of tetrahydrofuran was added 20 g (0.918 mole) of lithium borohydride in one portion. The mixture was stirred at 0° C. for 1 hour and then kept at a temperature below 25° C. overnight. The mixture was cooled to 0° C. and the pH adjusted to 3 with 6N hydrochloric acid (180 ml). The volume was reduced to 500 ml by rotary evaporation, and 1.5 L of water was added. The white precipitate was filtered, washed with cold water (500 ml) dried under reduce pressure to give 223.8 g (90%) of the title compound. M.P. =127° C. [α]D =36.66° (c=1.0, acetone) K.F. -6.55%.
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