Hydrochloric Acid → 3-fluoro-4-(2-phenyl-1H-pyrrolo[2,3-b]pyridin-4-yloxy)-phenylamine

To a solution of 3-fluoro-4-[2-phenyl-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrrolo[2,3-b]pyridin-4-yloxy]-phenyl-carbamic acid t-butyl ester in methanol, a 1:1 solution (10 mL) of hydrochloric acid and methanol was added. The mixture was stirred at room temperature for 4 hours. The resulting reaction mixture was concentrated under reduced pressure and ether was added to the resulting residue. After stirring for 2 hours, the produced solid was collected by filtering. Thus obtained hydrochloride was dissolved in water and neutralized to about pH 8 by adding 1 M sodium hydroxide aqueous solution. The resulting mixture was extracted with ethyl acetate. The organic layer was separated and washed with sodium chloride aqueous solution. The organic layer was dried with Na2SO4 and then filtered. The filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (hexane:ethyl acetate=1:1) to give the target compound as a white solid (81 mg, 0.25 mmol, 40% yield).