Sodium chlorite (30 mg, 0.33 mmol) was added to a water (0.3 ml)/2-methyl-2-propanol (1.2 ml) mixed solution of {[5-chloro-6-({4-[(5-methylpyrazin-2-yl)amino]quinazolin-6-yl}oxy)pyridin-3-yl]oxy}acetaldehyde (50 mg, 0.11 mmol) obtained in Example 32, 2-methyl-2-butene (0.051 ml, 0.48 mmol) and sodium dihydrogenphosphate (13 mg, 0.11 mmol), and the reaction solution was stirred at room temperature for 1 hour. Aqueous 1 N hydrochloric acid solution was added to the reaction solution, and extracted with chloroform/methanol (9:1). The organic layer was dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained residue was recrystallized from ethyl acetate to obtain the entitled compound (37 mg, yield: 77%) as a yellow solid.
