Subject selenium stabilized

Benzimidazole (but not 1-methylbenzimidazole) is oxidized by permanganate, dichromate or hydrogen peroxide to imidazole-4,5-dicarboxylic acid, while napth-[l,2-d]- and -[2,3-d]-imidazoles also form products in which the heterocyclic ring remains intact, hence demonstrating its stability to these conditions. With lead peroxide benzimidazole is subject to an unusual oxidation as it forms (101), also the reaction product of lead dioxide and 2,2 -bibenzimidazolyl. In dioxane, selenium dioxide oxidizes 2-methylbenzimidazole to o-hydroxyacetanilide (66RCR122). 

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