Electrochemical interconversion of 1-(p-tolyl)-6-methyl-2,4-diphenylpyrimidinium perchlorate and 1-(p-tolyl)-6-methylene-2,4-diphenylpyrimidine

It is shown that reduction of the 6-methyl-1-(p-tolyl)-2,4-diphenylpyrimidinium cation proceeds in two one-electron stages. In the first stage, an unstable radical is formed, and in the second stage, an unstable anion. As a result of dehydrogenation of the radical, the anhydro base 6-methylene-1-p-tolyl-2,4-diphenyl-6H-pyrimidine is formed. Oxidation of this compound in a single one-electron stage forms an unstable cation radical, the hydrogenation of which leads to the original pyrimidinium cation. Data obtained by cyclic voltametry and electrosynthesis with subsequent identification of the products have shown that, the same as in the reaction with the hydroxide anion, the methyl-substituted pyrimidinium cation acts as a CH-acid.Rostov State University, Rostov-on-Don 344101, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 71–75, January, 1999.     

Nature of weak inter-and intramolecular interactions in crystals 8. Influence of intermolecular contacts on the strength of intramolecular O-H...N bonds in crystals of 3-(2-hydroxyphenyl)-1,2,4-triazoles

The nature and energy of the intramolecular H-bond in 3-(2-hydroxyphenyl)-1,2,4-triazoles was studied by X-ray diffraction and quantum chemical methods. In this system, the conjugation does not additionally contribute to the enhancement of the H-bond energy. The cooperative effects lead to a strengthening of the intramolecular H-bond. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 396–402, March, 2006.     

Synthesis of the alkaloid dioxyline and other 6,7-dimethoxyisoquinolines in a modified ritter reaction

It has been found that aceto- and benzonitriles and 3,4-dimethoxyphenylacetone in the presence of acetylperchlorate or upon heating in polyphosphoric acid or polyphosphoric ester form the corresponding isoquinoline. The data indicate that the reaction proceeds like a typical Ritter reaction and is defined by electrophilic activation of the carbonyl group of the ketone and the nucleophilicity of the nitrile. This methodology gave the alkaloid dioxyline (dimoxyline), obtained in high yield by the use of benzoylhexachloroantimonate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 363–368, March, 1992.     

Synthesis of γ-pyrones,flavones, and isocoumarins by destructive oxidation of pyranylidenes and their benzo analogs

Preparative methods for the synthesis of isocoumarins, -pyrones, and flavones by destructive oxidation of methylenepyrans with potassium permanganate in acetone were developed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1320–1323, October, 1978.     

Unusual recyclization of 5-methyl-2, 4-diphenyl-6-(2-N,N-dimethylaminovinyl)-3-azapyrilium perchlorate

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, p. 134, January 1990.     

Photocyclization of 1,2-diaryl- and photobicyclization of 1,2,6-triarylpyridinium cations

New 1,2-diaryl- and 1,2,6-triarylpyridinium salts, containing various five- and six-membered heteroaromatic substituents in the 1, 2, and 6-positions of the pyridinium ring, were synthesized. New tetra- and hexacyclic compounds were prepared by photocyclization of the cations of these salts. Photocyclization proceeds through a singlet excited state with nonadiabatic formation of a dihydro intermediate, followed by its oxidative dehydrogenation. The structure and quantum yield of the formation of photoproducts are determined by steric and electronic effects of the substituents, and in bichromophore compounds by the presence of S-S intramolecular interfragment energy transfer.The article is dedicated to the memory of Professor G. N. Dorofeenko.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1518, November, 1984.     

Complex Formation in the System Bis[2-(trimethylammonio)ethyl] Succinate Diodide-Iodine in Solutions and in Crystal

The complex formation in the system bis[2-(trimethylammonio)ethyl] succinate diodide-iodine involves no more than two iodine molecules. The crystal structure of the salt [(CH3)3N(CH2)2OCOCH2]2(I3)2 is formed by layers of inorganic anions (I₃ ^-) and organic dications (centrosymmetric dications {[(CH₃)₃N · (CH₂)₂OCOCH₂]⁺}₂), evenly alternating along the a axis. The crystal structure of the salt [(CH₃)₃N(CH₂)₂·OCOCH₂]₂(I₃)₂(I₂)0.5 is formed by organic and inorganic layers evenly alternating along the [011] diagonal, with a centrosymmetric iodine molecule.     

Β-Chloro-Β-ferrocenylacrylaldehyde and its application in the synthesis of pyrylium and pyridine derivatives of ferrocene

-Chloro--ferrocenylacrylaldehyde, to which an s-cis configuration was assigned on the basis of the PMR spectral data, was synthesized from acetylferrocene by the Vilsmeier-Haack reaction. 2, 3, 6-Trisubstituted pyrylium salts with a ferrocenyl substituent in the 6 position were obtained by condensation of this aldehyde with -dicarbonyl compounds. The pyrylium salts were converted to the corresponding pyridines by the action of ammonium acetate in acetic acid. On the basis of the structures of the pyridines it was established that the aldehyde carbon atom initially attacks the -dicarbonyl compound with subsequent closing of the -unsubstituted pyrylium ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 599–602, May, 1977.