[NH2:1][C:2]([CH:4]1[CH2:8][CH:7](OS(C)(=O)=O)[CH2:6][N:5]1[C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])=[O:3].C1COCC1.[F-:26].C([N+](CCCC)(CCCC)CCCC)CCC.O>ClCCl>[NH2:1][C:2]([C@@H:4]1[CH2:8][C@H:7]([F:26])[CH2:6][N:5]1[C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])=[O:3]
In a 5.0 L 4-necked RB flask, fitted with a mechanical stirrer and reflux condenser, were added tert-butyl 2-(aminocarbonyl)-4-[(methylsulfonyl)oxy]pyrrolidine-1-carboxylate (100 gm, 0.32 M), THF (500 ml), a tetrabutylammonium fluoride solution (153.4 gm, 0.48 mol in 500 ml THF) and water (35 ml) at 25-35° C. while stirring. The reaction mixture was brought to 55-60° C. and maintained for 48-60 hrs while stirring. The progress of the reaction was monitored by HPLC and after ascertaining completion, the reaction mixture was poured slowly into an ice cold water (1.5 L) and dichloromethane (0.72 L) mixture. The aqueous layer was washed with additional MDC (210 ml×3). The organic layers were combined and washed with a saturated brine solution (0.5 L). The dichloromethane layer was distilled below 40° C. under vacuum and hexane (500 ml) was added to the resulting mass. The trace dichloromethane was distilled off. The resulting mass was taken as such to the next stage.
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