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 (141 mg, 271 μmol) produced in Example D10 in tetrahydrofuran (4 mL) were added triethylamine (113 μL, 813 μmol) and thiomorpholine (77 μL, 813 μmol), and the mixture was stirred at 60° C. for 3 hr. To the reaction mixture was added saturated aqueous sodium hydrogen carbonate solution (15 mL), and the mixture was extracted with ethyl acetate (15 mL, 10 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=20/80→0/100), and the fractions containing the object product were concentrated under reduced pressure. To the obtained residue were added diisopropyl ether and ethyl acetate, and the obtained precipitate was collected by filtration to give the title compound (117 mg, 73%) as a colorless amorphous solid.
