- Alkylpyridines transformations over acidic catalysts. An example of radical reactions on ionic surfaces
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4-Methyl-, 4-ethyl-, and 4-isopropylpyridine, ethyl-, and isopropylbenzene transformations were studied over the series of amorphous silica-aluminas. The main reactions of alkylpyridines were the transformations of the alkyl side chain. The crucial role of one-electron donor (radical) centres in the mentioned reactions was evidenced by the physicochemical characterization of the catalyst surfaces, the apparent correlation of activity vs. active centres concentration, and the dependence of product composition upon reaction conditions.
- Kijenski,Malinowski,Kowalczyk,Osawaru
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p. 719 - 736
(2007/10/03)
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- Substituent Effects on the CC Bond Strength, 18. - Stabilization of Alkyl Radicals by 4-Pyridyl, 1-Naphthyl or 2-Naphthyl Substituents in α-Position
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The formation of the α-substituted radicals 7-9 with the 4-pyridyl (7), 1-naphthyl (8), and the 2-naphthyl (9) substituent by thermolysis of their dimers 1-3 in solution was investigated.The activation parameters of the homolysis of the central CC bond were obtained from kinetic measurements of the thermal cleavage of 1-3 in the presence of radical scavengers.These data were compared with those obtained from the thermolysis of alkanes which cleave into α-alkyl branched radicals, and which lose the same amount of strain during the dissociation.The "strain-free" radical stabilization enthalpies of the α-substituted radicals were obtained in this way. - Key Words: Bond cleavage, C-C, kinetics of / Radicals, stability of
- Herberg, Clemens,Peyman, Anuschirwan,Noelke, Margot,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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p. 881 - 884
(2007/10/02)
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- Reactions of 2-Chloro-2-(4-pyridyl)propane with Nucleophiles. Substitution on Tertiary Carbon
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The reaction of 2-chloro-2-(4-pyridyl)propane (2) with lithium 2-propanenitronate affords the C-alkylation product 2-nitro-3-(4-pyridyl)-2,3-dimethylbutane (3), the Michael-adduct 2-nitro-2-methyl-4-(4-pyridyl)pentane (4), 4-isopropenylpyridine (5) and 2-
- Feuer, Henry,Doty,James K.,Kornblum, Nathan
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p. 783 - 787
(2007/10/02)
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