O-Phenylenediamine → 1H-benzimidazole, 2-(4-methyl-2-pyridinyl)-

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Reaction Conditions

Reaction Steps

450 g of polyphosphoric acid, 40 g (0.29 mol) of 4-methyl-pyridine-2-carboxylic acid amide and 31 g (0.29 mol) of o-phenylendiamine are added in a three-neck round-bottom flask, equipped with a condenser, a thermometer and mechanical stirring. The mixture is heated at 210° C. for 4 hours. At the end, the mixture is cooled at 70° C. and the crude is added to 1 L of water. Basify with a 50% aqueous solution of sodium hydroxide and filter the solid obtained. Crystallize from absolute ethanol. The product 2-(4-methylpyridin-2-yl)-1H-benzoimidazol is obtained with a yield of 85%. Melting point: 228-9° C.

Provenance & Evidence