N-(3-Chloro-4-fluorophenyl)-4-(3-hydroxypropyl)-1,2,5-oxadiazole-3-carboxamide (60 mg, 0.20 mmol) was dissolved in anhydrous DCM (2 mL), followed by addition of TEA (57 μL, 0.41 mmol). The reaction was stirred and cooled to 0° C., and methanesulfonyl chloride (29 μL, 0.37 mmol) was added drop-wise. The reaction was quenched with water and diluted with DCM. The organic layer was separated, dried over Na2SO4, filtered, concentrated and purified by silica gel chromatography (25%-75% EtOAc/hexane) to give the desired product (60 mg, 80%). LCMS for C13H14ClFN3O5S (M+H)+: m/z=378.
