To a solution of N-{3-[{2-[(chloroacetyl)amino][1,3]thiazolo[5,4-d]pyrimidin-5-yl}(methyl)amino]phenyl}-3-(1-cyano-1-methylethyl)benzamide (140 mg, 269 μmol) produced in Example D10 in tetrahydrofuran (4 mL) were added triethylamine (112 μL, 807 μmol) and thiomorpholine 1,1-dioxide (109 mg, 807 μmol), and the mixture was stirred at 60° C. for 16 hr. To the reaction mixture was added saturated aqueous sodium hydrogen carbonate solution (10 mL), and the mixture was extracted with ethyl acetate (15 mL, 5 mL). The combined organic layer was washed with saturated brine (5 mL), and dried over anhydrous sodium sulfate. The insoluble material was filtered off, and the filtrate was concentrated under reduced pressure. The obtained residue was purified by basic silica gel column chromatography (hexane/ethyl acetate=40/60→20/80), and the fractions containing the object product were concentrated under reduced pressure. The obtained residue was recrystallized from ethanol to give the title compound (94 mg, 56%) as a colorless solid.
