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 then methanesulfonyl chloride (29 μL, 0.37 mmol) was added dropwise. The reaction was quenched with water and diluted with DCM. The organic solution was separated, dried over Na2SO4, filtered, concentrated and purified by silica gel chromatography (25%-70% EtOAc/hexane) to give the desired product (19 mg). LCMS for C13H14ClFN3O5S(M+H)+: m/z=378.
