Trimethylazanium;chloride → 1-(6-Chloro-3-hydroxypyridin-2-YL)ethan-1-one

To a suspension (80 mL) of aluminum chloride (14.3 g) in toluene was added trimethylammonium chloride (4.75 g), and the mixture was stirred under argon atmosphere at room temperature for 1 hr. To the mixture was added a solution (80 mL) of 1-[3-(benzyloxy)-6-chloropyridin-2-yl]ethanone (8.66 g) synthesized above in toluene, and the mixture was stirred at room temperature for 4 hr. The reaction mixture was concentrated under reduced pressure, saturated aqueous Rochelle salt solution was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (0-5% ethyl acetate/hexane) to give the title object compound (4.89 g, 86%) as a pale-yellow solid.