To a solution of 2-(2-(2-methoxyphenyl)aminoanilin-5-yl)benzoxazole (see Working Example 30-1) (48.0 mg, 0.135 mmol) in dimethylformamide (2 mL) was added an aqueous solution of acetaldehyde (approx. 90%, 20.5 μL, 0.405 mmol) and oxone (53.9 mg, 0.0878 mmol), and this was stirred at room temperature for 3 hours. After the reaction was complete, aqueous potassium carbonate solution was added, this was filtered and washed with water. The crystals obtained were purified by silica gel column chromatography to yield the title compound (18.2 mg, 38% yield) as white crystals.
