Oxidative Ammonolysis of Dialkylpyridines

The cluster approach was used to simulate the chemisorption of dialkylperidines on the surface of a vanadium oxide catalyst, involving active centers of various nature, and to assess the enthalpy of proton abstraction from the alkyl substituents. Under oxidative ammonolysis conditions, the order of the transformation of the substituents in unsymmetrical dialkylpyridines into the cyano group is determined by the enthalpy of their deprotonation.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 159–163.Original Russian Text Copyright © 2005 by Vorob’ev, Sembaev.     

Mechanism of Formation of the Cyano Group from the Chloromethyl,Methoxymethyl, and Alkoxycarbonyl Substituents in the Aromatic Ring Under Conditions of Oxidative Ammonolysis

Upon gas-phase oxidative ammonolysis on vanadium oxide catalysts 4-nitro-, 2-halo, 2- and 4-hydroxy-, and 4-methoxy- and 4-phenoxytoluenes much less selectively convert into the corresponding substituted benzonitriles than their derivatives with the methyl group substituted by chloromethyl, methoxymethyl, or alkoxycarbonyl groups. This fact is explained in terms of different mechanisms of formation of the cyano group: The methyl group converts via deprotonation to form a carbanion, whereas the heteroatomic groups, via the energetically more favorable carbocation formation.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 313–317.Original Russian Text Copyright © 2005 by Vorob’ev, Sembaev.     

Effect of Reaction Medium on the Composition of Vanadium-Titanium Catalyst in Oxidative Ammonolysis of Alkylpyridines

The influence exerted by the concentration of alkylpyridines on the chemical composition of a vanadium-titanium catalyst under oxidative ammonolysis conditions was subjected to a comparative study.     

Reactivity of Isomeric Picolines in Oxidative Ammonolysis on a Vanadium Oxide Catalyst

The reactivity of isomeric picolines in their oxidative ammonolysis on a vanadium oxide catalyst, as measured by the rate constants of cyanopyridine formation, increases in the order 3-picoline < 2-picoline < 4-picoline. Correlations were found between the mentioned rate constants and the gas-phase basicities of the starting compounds, with constants characterizing electron-acceptor properties of the nitrogen atoms, as well as the deprotonation constants of the methyl groups of picolines in the gas phase or bound via the nitrogen atoms with clasters modeling Brønsted acid centers of the vanadium oxide surface.     

Oxidative ammonolysis of 3- and 4-methylpyridines on vanadium oxide catalysts modified with titanium and tin oxides

Catalytic properties of vanadium-titanium-tin oxides catalysts of various compositions were studied in oxidative ammonolysis of 3- and 4-methylpyridines.     

On some peculiarities of phthalimide formation in the oxidative ammonolysis of o-xylene

In the oxidative ammonolysis of o-xylene on oxide catalysts, phthalimide can be obtained from phthalodinitrile through an intermediate phthalocyanine step. The catalyst ability to form phthalocyanine can be used to estimate its selectivity to phthalimide.

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Effect of oxides of the IV and VI group metals on the polymorphic transformation of anatase into rutile

An effect of some metal oxides on the polymorphic transformation of anatase into rutile and on the rate of dissociation of V₂O₅ in the systems V₂O₅-TiO₂ and V₂O₅-TiO₂-Me_xO_y has been studied, where Me_xO_y is SnO₂, WO₃, Cr₂O₃ or ZrO₂.     

Novel Delta‐Opioid‐Receptor‐Selective Ligands in the 14‐Alkoxy‐Substituted Indolo‐ and Benzofuromorphinan Series

Several new indolo‐ and benzofuromorphinans substituted at the positions 5 and 14 were prepared and tested in vitro by means of opioid‐receptor binding and functional ([³⁵S]GTPγS binding) assays. All compounds 1 – 11 displayed high affinity for δ opioid‐binding sites (Table 1). Compound 4 proved to be an agonist, and all other compounds were antagonists. The presence of a Me group at position 5 induced no change in δ affinity (see 1 vs. 3 ), but decreased the μ and κ affinities. An EtO group at position 14 conferred a very high affinity and also high selectivity to δ opioid receptors (see 2 and 10 ). Chain elongation of the 14‐alkoxy group resulted in compounds with reduced δ affinity and selectivity (see 4 and 11 and also 5 – 9 ). The results of the present study indicate that the 5‐ and 14‐positions of indolo‐ and benzofuromorphinans represent critical sites that could be a trigger to develop new compounds with increased δ affinity and/or selectivity.