Potassium Carbonate → 5-(Benzoxazol-2-yl)-2-methyl-1-(3-phenylpropyl)benzimidazole

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Reaction Steps

To a suspension of 2-(4-fluoro-3-nitrophenyl)benzoxazole (see Working Example 15-2) (300 mg, 1.16 mmol) in ethanol (5 mL) was added potassium carbonate (176 mg, 1.28 mmol) and 3-phenylpropylamine (189 mg, 1.39 mmol), and this was heated to reflux for 3 hours. After the reaction was complete, this was cooled to room temperature, water was added, and the precipitated crystals were filtered, washed with water and then dried. To a tetrahydrofuran solution (5 mL) of the crystals obtained was added 10% palladium-carbon (50 mg). A hydrogen atmosphere was substituted in the flask, and this was stirred at room temperature for 6 hours. After the reaction was complete, this was filtered through Celite and the filtrate was concentrated. The residue obtained was dissolved in methanol (5 mL), and to this was added 1,1,1-trimethoxyethane (108 mg, 0.896 mmol), and this was heated to reflux for 6 hours. After the reaction was complete, this was concentrated, and the residue obtained was purified by silica gel column chromatography to yield the title compound (58.5 mg, 14% yield) as white crystals.

Provenance & Evidence