Acetyl chloride → N-(3-{[2-(acetylamino)-7-cyano-1,3-benzothiazol-6-yl]oxy}phenyl)-3-(1-cyano-1-methylethyl)benzamide

To a solution of N-{3-[(2-amino-7-cyano-1,3-benzothiazol-6-yl)oxy]phenyl}-3-(1-cyano-1-methylethyl)benzamide (200 mg, 0.44 mmol) produced in Example 1 (iv) in pyridine (2 mL) was added acetyl chloride (41 μL, 0.57 mmol), and the mixture was stirred at room temperature for 2 hr. The reaction mixture was concentrated under reduced pressure. The residue was suspended in ethyl acetate (20 mL), washed successively with 5% aqueous sodium hydrogen carbonate solution (20 mL) and saturated brine (20 mL), and dried over anhydrous sodium sulfate. Insoluble material was filtered off, and the filtrate was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (ethyl acetate/n-hexane=50/50→100/0), and the obtained solution was concentrated under reduced pressure. The residue was crystallized from ethyl acetate to give the title compound (127 mg, 58%) as a white powder.