Acetyl chloride → 5-(Benzoxazol-2-yl)-1-(4-methoxyphenyl)-2-methylbenzimidazole

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Reaction Steps

2-(4-(4-methoxyphenylamino)-3-nitrophenyl)benzoxazole (Working Example 15-3) (150 mg, 0.415 mmol) was added to a tetrahydrofuran (5 mL) solution containing 10% palladium-carbon (50 mg), and a hydrogen atmosphere was substituted in the flask and this was stirred at room temperature for 3 hours. After the reaction was complete, this was filtered through Celite and the filtrate was concentrated. To a solution of the oil obtained in toluene (5 mL) was added acetyl chloride (70.8 mg, 0.902 mmol), and this was heated to reflux with stirring for 2.5 hours. After the reaction was complete, this was cooled to room temperature, saturated aqueous sodium hydrogen 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 crystals that were purified by silica gel column chromatography to yield the title compound (47 mg, 32% yield) as dark brown crystals.

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