Synthesis and some properties of 2H-benzimidazole 1,3-dioxides

The synthesis of novel 2H-benzimidazole 1,3-dioxides on the basis of benzofuroxans interaction with alcohols in acids is described. The formation of a stable secondary carbocation from alcohol is necessary for formation of 2H-benzimidazole 1,3-dioxide while substituents in benzofuroxans don't prevent the reaction. Under heating 2H-benzimidazole 1,3-dioxides are rearranged to 3H-[2,1,4]benzoxadiazine 4-oxides whose stability depends on substituents in the aromatic ring. Under irradiation oxadiazines are converted back to 2H-benzimidazole 1,3-dioxides.

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