B. Trofimov, A. M. Vasil’tsov, E. Schmidt
Oct 1, 2005
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0
Influential Citations
22
Citations
Journal
European Journal of Organic Chemistry
Abstract
2,6-Bis(pyrrol-2-yl)pyridine (4), 2-(pyrrol-2-yl)-6-[2-(1-vinylpyrrol-2-yl)]pyridine (5), 2,6-bis[2-(1-vinylpyrrol-2-yl)]pyridine (6), 2,6-dimethyl-3,5-bis[2-(1-vinylpyrrol-2-yl)] pyridine (9), 3-acetyl-2,6-dimethyl-5-[2-(1-vinylpyrrol-2-yl)]pyridine (10), and 2,6-dimethyl-3-(pyrrol-2-yl)-5-[2-(1-vinylpyrrol-2-yl)]pyridine (11) have been synthesized from the oximes of the corresponding diacetylpyridines in a one-pot procedure by treatment with acetylene in MOH/DMSO systems (M = Li, K) at 80–140 °C under pressures of 25–30 atm, thus illustrating the applicability and general character of the reaction for synthesis of diverse dipyrrole-pyridine assemblies and their N-vinyl and acetyl derivatives. A stable 4·DMSO complex with bifurcated NH···O···HN bonding has been isolated and its X-ray structure determined. Quantum chemical analysis at the B3LYP/6-311G* level shows that the cis-cis conformation of 4 is most stable, with the cis-trans and trans-trans forms accordingly less favorable by 3.2 and 7.8 kcal mol–1. Activation barriers of cis-cis-to-cis-trans and cis-trans-to-trans-trans dynamics are 8.3 and 9.5 kcal mol–1, respectively, which means that internal rotation of the pyrrole rings in 4 is essentially hindered. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)