Free-radical hydroxymethylation of benzimidazole
Several benzimidazole derivatives were subjected to free-radical hydroxymethylation. Benzimidazole displays lower activity than quinoline in the first stage of the transformation, viz., in the addition of the hydroxymethyl radical. The yields of hydroxymethylation products are also determined by the ability of the intermediate benzimidazolium cation radicals to undergo oxidation and are increased in the presence of a catalyst, viz., silver ions.