796 mg of m-chloroperbenzoic acid (>65%) was added to toluene (20 mL) solution of 898 mg of 2-allyl-6-(methylthio)-1-pyridin-2-yl-3H-pyrazolo[3,4-d]pyrimidin-3one, and stirred for 30 minutes. 1.60 mL of N,N-diisopropylethylamine, 800 mg of [5-amino-2-(4-methylpiperazin-1-yl)phenyl]methanol and 10 mL of tetrahydrofuran were added to the reaction liquid, and stirred overnight. Aqueous saturated sodium hydrogencarbonate solution was added to the reaction liquid, and extracted with a mixed solution of chloroform/isopropanol (80/20). This was dried with anhydrous magnesium sulfate, the solvent was evaporated away, and the residue was purified through basic silica gel column chromatography (hexane/ethyl acetate=50/50 to 0/100). The resulting crystal was recrystallized from ethanol to obtain 941 mg of the entitled compound as a white crystal.
