Cyclization of 1-alkyl-3-[(2Z)-2,4-diaryl-4-oxobut-2-en-1-yl]-1H-benzimidazol-3-ium bromides occurs in the presence of MeONa at a reduced temperature of 5–10°C via a 1,5-electrocyclization mechanism to give 3a,4-dihydro-3H-pyrrolo[1,2-a]benzimidazoles. These are unstable under the reaction conditions and are readily converted to {1-[2-(alkylamino)phenyl]-4-phenyl-1H-pyrrol-3-yl}(phenyl)methanones.
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V. G. Kartsev (editor), Selected Methods of Synthesis and Modification of Heterocycles [in Russian], Vol. 1, IBS Press, Moscow (2003), p. 393.
L. Potikha, V. Kovtunenko, A. Turelyk, A. Turov, and A. Tolmachev, Synth. Commun., 38, 2016 (2008).
L. M. Potikha, A. R. Turelyk, and V. A. Kovtunenko, Khim. Geterotsikl. Soedin., 95 (2010). [Chem. Heterocycl. Comp., 46, 82 (2010)].
X-c. Zhang and W-y. Huang, Tetrahedron Lett., 38, 4827 (1997).
X-c. Zhang and W-y. Huang, Tetrahedron, 54, 12465 (1998).
E. Pohjala, Tetrahedron Lett., 13, 2585 (1972).
Y. Tamura, N. Tsujimoto, Y. Sumida, and M. Ikeda, Tetrahedron, 28, 21 (1972).
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 552–556, April, 2011.
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Potikha, L.M., Turelyk, A.R. & Kovtunenko, V.A. 1,5-Electrocyclization of 1-alkyl- 3-[(2Z)-2,4-diaryl-4-oxobut-2-en-1-yl]-1H-benzimidazol-3-ium bromides. Chem Heterocycl Comp 47, 452–455 (2011). https://doi.org/10.1007/s10593-011-0780-6
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DOI: https://doi.org/10.1007/s10593-011-0780-6