Synthesis,complexation, and photochemistry of benzobisthiazole-based bis(crown ether)

Benzobisthiazole-based bis(crown ether) was synthesized and its complexation with alkali and alkaline earth cations was studied. Photochemical transformations of the free ligand and its complexes with alkaline earth cations involve E,Z-photoisomerization and [2+2] photocycloaddition. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2056–2065, September, 2005.     

A hexacyclic ent-trachylobane diterpenoid possessing an oxetane ring from Mitrephora glabra

[chemical reaction: see text]. Three new ent-trachylobane diterpenoids (1-3) were isolated and structures elucidated from Mitrephora glabra Scheff. (Annonaceae). Mitrephorone A (1) possesses a hexacyclic ring system with adjacent ketone moieties and an oxetane ring, both of which are unprecedented among trachylobanes. All compounds were evaluated for cytotoxicity against a panel of cancer cells, where 1 displayed the most potent and broadest activity, and against a battery of antimicrobial assays, where all compounds were approximately equipotent.     

QSPR Modeling of the Reactivity Parameters of Monomers in Radical Copolymerizations

For a series of monomers, QSPR test analysis is performed by optimizing the correlation weights of the local invariants of molecular graphs representing monomer structures in order to construct models of the reactivity parameters of monomers Q and e. This approach may be used as a tool in reactivity predictions for monomers for which no experimental data on Q and e are available.Original Russian Text Copyright © 2004 by A. A. Toropov, V. O. Kudyshkin, N. L. Voropaeva, I. N. Ruban, and S. Sh. Rashidova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 994–998, November–December, 2004.     

Synthesis of partially hydrogenated pyrazolo[3,4-b]quinolinones by condensation of 3-amino-5-methylpyrazole with aromatic aldehydes and dimedone

Cyclocondensation of 3-amino-5-methylpyrazole with 2-arylmethylidene-5,5-dimethylcyclohexane-1,3-diones or 9-aryl-3,3,6,6-tetramethyl-2,3,4,5,6,7,8,9-octahydro-1H-xanthene-1,8-diones, as well as with synthetic precursors of the latter (para-substituted benzaldehydes and dimedone), in dimethylformamide or methanol gives the corresponding 4-aryl-3,7,7-trimethyl-2,4,6,7,8,9-hexahydropyrazolo[3,4-b]quinolin-5-ones. The structure of 4-(4-methoxyphenyl)-3,7,7-trimethyl-2,4,6,7,8,9-hexahydropyrazolo[3,4-b]quinolin-5-one was proved by the X-ray diffraction data.     

EPR study of spin adducts of silyl and phosphonyl radicals with higher internal perfluoroalkenes

The EPR method was used to study the structure of spin adducts of silyl and phosphonyl radicals with higher internal perfluoroalkenes. The capacity for spin adducts to split off hydrogen atoms is determined by the degree of steric screening of the free radical center. The preparative photochemical reaction of hydrosilanes and dialkyl phosphites with perfluoro-4-methylpent-2-ene leads to regiospecific hydrosilylation and hydrophosphorylation products with yields up to 80%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1018–1023, May, 1991.     

Synthesis of modified hexaprenol WC5OH from glutaraldehyde derivatives

A new procedure was developed for building linear Z-isoprenoids from glutaraldehyde derivatives as nonisoprenoid precursors, and is illustrated by the synthesis of hexaprenol WC₅OH.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 89–97, January, 1990.     

Synthesis of condensed systems containing the tetrazole ring by base-catalyzed intramolecular cyclization of quaternary ammonium salts

Quaternary ammonium salts containing propargyl and 3-(2-methyltetrazol-5-yl)propargyl groups undergo base-catalyzed cyclization at room temperature with self heating to form condensed heterocyclic systems containing the tetrazole ring. Heating at 90–92°C for 2 h is necessary to cyclize the allyl analogs of the starting salts.Communication 234 of the series Research on Amines and Ammonium Compounds. For 233, see [1].Institute of Organic Chemistry, National Academy of Sciences of the Republic of Armenia, Erevan 375094. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 390–394, March, 1999.     

Kinetics of formation of a linear polymer-polymer network system in the presence of 3d metal chelates

For semi-interpenetrating polymer networks (semi-IPNs) based on an incompatible polyurethane network/linear polymethylmethacrylate pair formed in situ in the presence of 3d metal chelates, we have studied the effect of the system composition on the kinetics of formation of the components and the nature of complex formation between the metal compound and the polymer matrix. The ratio of the system components has been shown to have an effect on the selection of the macroligand in formation of complexes of the metal chelate with the polar groups of the semi-IPN, where the general character of the kinetic behavior for the formation of the network and the linear polymer is preserved. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 6, pp. 351–356, November–December, 2006.     

Quantum-chemical study of spectral and luminescent properties and photochemistry of polyatomic molecules

The potential of a package of quantum-chemical software programs for exploring physicochemical problems pertaining to polyatomic organic molecules is highlighted. The results of investigation into the spectral, luminescent, and photochemical properties of molecules are discussed. The necessity of development of target-oriented models for studying the problems of physics and chemistry of molecules is emphasized.