C(OC([O:6][CH:7]1[C:12]2[CH:13]=[CH:14][S:15][C:11]=2[S:10](=[O:17])(=[O:16])[N:9]([CH2:18][CH2:19][CH2:20][O:21][CH2:22][CH3:23])[CH2:8]1)C)C.C([Li])CCC.[S:29](=[O:31])=[O:30].O.O.O.C([O-])(=O)C.[Na+].[NH2:40]OS(O)(=O)=O>C1COCC1.O>[CH2:22]([O:21][CH2:20][CH2:19][CH2:18][N:9]1[CH2:8][CH:7]([OH:6])[C:12]2[CH:13]=[C:14]([S:29]([NH2:40])(=[O:31])=[O:30])[S:15][C:11]=2[S:10]1(=[O:17])=[O:16])[CH3:23]A solution of the product from Step C (13.25 g, 36.5 mmol) in THF (250 mL) was degassed under nitrogen and cooled to -60° C. in a dry-ice/isopropanol bath. n-Butyllithium (16.0 mL of a 2.5M solution, 40 mmol) was added slowly over 5 min and the mixture was stirred at -60° C. for 45 min followed by the introduction of excess sulfur dioxide gas into the flask. The mixture was allowed to warm to room temperature over two hours and the solvent was removed by evaporation. The residue was mixed with water (200 mL) and sodium acetate trihydrate (13.91 g, 102.2 mmol) followed by the addition of hydroxylamine-O-sulfonic acid (6,9 g, 61.32 mmol). The mixture was stirred at room temperature for 18 hr and then extracted with ethyl acetate (5×15 mL). The combined extracts were evaporated and the residue dissolved in THF (150 mL), mixed with 2N HCl (10 mL), warmed gently for 1 hr and then evaporated to a residue. The residue was mixed with ethyl acetate (100 mL) and water (100 mL). The organic layer was separated, washed with saturated aqueous sodium chloride, dried (MgSO4) and evaporated to a residue which was purified by column chromatography (silica, gradient, 3:1 hexane/ethyl acetate to 7:3 methylene chloride/methanol) to provide a pale yellow solid (11.6 g, 86%): mp 140°-145° C. dec. Analysis. Calculated for C11H18N2O6S3 : C, 35.66; H, 4.90; N, 7.56. Found: C, 35.79; H, 4.80; N, 7.47.
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