To a solution of Example 182D (54 mg, 0.112 mmol) in 5 mL dichloromethane was added diisopropylethylamine (58.9 μL, 0.337 mmol) and ethanesulfonyl chloride (26.6 μL, 0.281 mmol). The mixture was stirred at ambient temperature for 16 hours. Another 1.5 equivalents ethanesulfonyl chloride (16 μL) and 2.0 equivalents diisopropylethylamine (39 μL) were added. The mixture was continued to stir overnight. The mixture was concentrated. The residue was taken into dioxane (6 mL) and treated with sodium hydroxide (2810 μL, 2.81 mmol, 1N aqueous solution). The mixture was heated at 60° C. for 1 hour to hydrolyze the bis-sulfonamide to the manosulfonamide. To the reaction mixture, saturated ammonium chloride solution was added, extracted with ethyl acetate (3×), washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated and the residue was purified by column chromatography on silica gel with a gradient of 0-8% methanol in dichloromethane to give the title compound (10 mg, 0.017 mmol, 16% yield).
