- Synthesis, Structure, and Photochemical Behavior of [5]Heli-viologen Isomers
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The syntheses of isomeric helical viologens that have potential applications in supramolecular chemistry and catalysis have been developed. The structures of the molecules and their solid-state packing motifs have been determined by X-ray crystallography. Computational studies demonstrate that the magnitude of their racemization barriers is primarily determined by the identity of the helical scaffold and is insensitive to the placement of the viologen functional group. The isomers are similar in their photophysical behavior but very different in their photochemical behavior.
- Zhang, Xiaoping,Clennan, Edward L.,Arulsamy, Navamoney,Weber, Rachael,Weber, Jacob
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p. 5474 - 5486
(2016/07/13)
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- Ruthenium-catalysed synthesis of 2- and 3-substituted quinolines from anilines and 1,3-diols
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A straightforward synthesis of substituted quinolines is described by cyclocondensation of anilines with 1,3-diols. The reaction proceeds in mesitylene solution with catalytic amounts of RuCl3·xH 2O, PBu3 and MgBr2·OEt2. The transformation does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy and chloro substituents as well as naphthylamines were shown to participate in the heterocyclisation. In the 1,3-diol a substituent was allowed in the 1- or the 2-position giving rise to 2- and 3-substituted quinolines, respectively. The best results were obtained with 2-alkyl substituted 1,3-diols to afford 3-alkylquinolines. The mechanism is believed to involve dehydrogenation of the 1,3-diol to the 3-hydroxyaldehyde which eliminates water to the corresponding α,β-unsaturated aldehyde. The latter then reacts with anilines in a similar fashion as observed in the Doebner-von Miller quinoline synthesis.
- Monrad, Rune Nygaard,Madsen, Robert
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experimental part
p. 610 - 615
(2011/02/28)
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