To a solution of 2-(2-benzylaminoanilin-5-yl)benzoxazole (see Working Example 17-2) (80.0 mg, 0.254 mmol) in dimethylformamide (2 mL) was added an aqueous solution of acetaldehyde (approx. 90%, 47.7 μL, 0.761 mmol) and oxone (102 mg, 0.165 mmol), and this was stirred at room temperature for 3 hours. After the reaction was complete, aqueous potassium carbonate solution was added, and this was extracted with ethyl acetate. The organic layer obtained was dried over anhydrous sodium sulfate, filtered, and concentrated to give an oil that was purified by silica gel column chromatography to yield the title compound (35.2 mg, 41% yield) as light brown crystals.
