V. Samsonov, I. Bagryanskaya, Y. Gatilov
Aug 1, 2011
Citations
0
Influential Citations
5
Citations
Journal
Russian Chemical Bulletin
Abstract
AbstactThermal transformations of 2H-benzimidazole 1,3-dioxides represented by spiro[2H-benz-imidazole-2,1′-cyclohexane] 1,3-dioxide and its 5-nitro derivative were studied. Their heating resulted in reversible isomerization to spiro[3H-[2,1,4]benzoxadiazine-3,1′-cyclohexane] 4-oxides. More prolonged heating of 2H-benzimidazole 1,3-dioxides caused sequential elimination of the first and then (at higher temperature) the second N-oxide oxygen atom to form 2H-benzimidazole derivatives, which upon further heating were transformed to 7,8,9,10-tetrahydro-6H-azepino[1,2-a]benzimidazoles. A scheme of the process was suggested, which described the experimental data obtained. Spiro[3H-[2,1,4]benzoxadiazine-3,1′-cyclohexane] 4-oxides on exposure to the sunlight were quantitatively transformed to 2H-benzimidazole 1,3-dioxides.