Ammonia → 5-(Benzoxazol-2-yl)-2-methyl-1-phenylbenzimidazole

Participants

Reaction Conditions

Reaction Steps

A 2-neck flask (20 mL) equipped with reflux condenser was charged with 2-methyl-1-phenylbenzimidazole-5-carboxylic acid (see Synthesis Example 1-3) (0.15 g, 0.59 mmol), 2-aminophenol (0.09 g, 0.82 mmol) and polyphosphoric acid (approx. 2 g), and this was heated to 160° C. and stirred under those conditions for 20 hours. After being allowed to cool to room temperature, ice was added and concentrated aqueous ammonia (28%) was added to the liquid to give approx. pH 9. The precipitated crystals were filtered off, these were washed with distilled water (approx. 3 mL, 2 times), and then dried to yield the title compound (0.13 g, 68% yield) as greenish pale yellow crystals.

Provenance & Evidence