2-chloro-6-(difluoroMethoxy)pyridine

16879-02-0

1885-46-7

1214377-45-3

To a vigorously stirred solution of 6-chloropyridin-2-ol (0.13 g, 1.0 mmol) in acetonitrile (2 mL) was added 6 M aqueous potassium hydroxide (2 mL) at room temperature. Subsequently, difluoromethyl trifluoromethanesulfonate (0.38 mL, 3.0 mmol, 3 equiv) was added slowly and dropwise to the reaction mixture. The temperature was controlled during the reaction by means of a water bath to maintain it at room temperature (note that the reaction is exothermic) and stirring was continued for 30 minutes. Upon completion of the reaction, the mixture was diluted with water (20 mL) and extracted sequentially with ether (2 x 10 mL) and ethyl acetate (3 x 10 mL). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography with the eluent of pentane/diethyl ether (100:0 to 70:30 gradient elution) to afford the pure 2-chloro-6-difluoromethoxypyridine (129 mg, 72% yield). The structure of the product was confirmed by nuclear magnetic resonance hydrogen spectroscopy (1H NMR), carbon spectroscopy (13C NMR), fluorine spectroscopy (19F NMR) and high resolution mass spectrometry (HRMS).