A mixture of tert-butyl ((2S)-1-((2-(4-hydroxyphenyl)[1,3]oxazolo[4,5-c]pyridin-6-yl)oxy)propan-2-yl)carbamate (300 mg), 2-(2,2-difluorocyclopropyl)ethyl methanesulfonate (312 mg), potassium carbonate (215 mg) and DMF (5 mL) was stirred overnight at 70° C. The reaction mixture was allowed to cool to room temperature, and 2-(2,2-difluorocyclopropyl)ethyl methanesulfonate (935 mg) and potassium carbonate (645 mg) were added thereto. The obtained mixture was stirred overnight at 70° C. To the reaction mixture was added water, and the mixture was extracted with ethyl acetate. The combined organic layer were washed with saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (239 mg).
