To a suspension of NaH (60%, 195 mg) in THF (dry) (10 mL) was added 2-chloroethanesulfonyl chloride (0.307 mL) at 0° C. and the mixture was stirred for 10 min at the same temperature. A solution of 6′-(cyclohexyloxy)-5-fluoro-3,3′-bipyridin-2-amine (280 mg) in THF (dry) (10 mL) was added at 0° C. and the mixture was stirred at room temperature under nitrogen for 1 day. The mixture was quenched with water at 0° C. carefully. EtOAc and THF were added and the organic layer was separated, washed with brine, dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was crystallized from MeCN-THF/IPE to give the title compound (81.1 mg) as colorless crystals.
