The 4-(5-fluoro-3-(2,2,2-trifluoroethyl)-2-oxo-1-benzimidazolinyl)piperidine (~10 mmol.) above was dissolved in anhydrous DMF (25 mL) followed by the addition of 1,1-dioxido-2-(4-bromobutyl)-5-chloro-1,2-benzisothiazol-3(2H)-one (3.54 g, 10 mmol.) and triethylamine (1.4 mL, 10 mmol.) and allowed to stir at 50° C. under an inert atmosphere for three hours or until reaction was complete. The cooled solution was diluted with EtOAc and washed with NaHCO3 /Na2CO3 solutions, water (3×), and the organic layer dried (Na2SO4), filtered and the solvent evaporated to give 1,1-dioxido-2-(4-(4-(5-fluoro-3-(2,2,2-trifluoroethyl)-2-oxo-1-benzimidazolinyl)piperidin-1-yl)butyl)-5-chloro-1,2-benzisothiazol-3(2H)-one as a viscous oil. This material was dissolved in EtOAc (50 mL) and excess HCl gas/EtOAc was added to give an immediate copious white precipitate which was gently digested in the warmed EtOAc to give the crystalline HCl salt of Compound A, mp: 255-257° C. Analysis calculated for C25H25ClF4N4O4S.HCl: C,48.00; H,4.19; N, 8.96; found: C,47.96; H, 4.17; N, 8.93. The NMR was consistent with structure.
