Synthesis and Antiviral Activity of N-Heterocyclic Hydrazine Derivatives of Camphor and Fenchone

Chemistry of Heterocyclic Compounds - Alkylation of the primary amino group of hydrazones of (+)-camphor and (–)-fenchone with dihaloalkanes leading to the production of novel...     

Acid-catalyzed transformations of diepoxy derivatives of terpinolene

Transformations of diepoxy derivatives of terpinolene under conditions of homogeneous and heterogeneous acid catalysis were studied. Qualitative and quantitative compositions of the reaction mixtures were found to depend on the acidity of the medium and mutual orientation of the epoxide rings in the p-menthane skeleton. The experimental data were compared with the results of computer simulation of the most probable transformation pathways in terms of molecular mechanics and quantum-chemical methods.     

Large deviations for a symmetric branching random walk on a multidimensional lattice

An important role in the theory of branching random walks is played by the problem of the spectrum of a bounded symmetric operator, the generator of a random walk on a multidimensional integer lattice, with a one-point potential. We consider operators with potentials of a more general form that take nonzero values on a finite set of points of the integer lattice. The resolvent analysis of such operators has allowed us to study branching random walks with large deviations. We prove limit theorems on the asymptotic behavior of the Green function of transition probabilities. Special attention is paid to the case when the spectrum of the evolution operator of the mean numbers of particles contains a single eigenvalue. The results obtained extend the earlier studies in this field in such directions as the concept of a reaction front and the structure of a population inside a front and near its boundary.     

Synthesis and colloidochemical properties of cerium dioxide hydrosols stabilized by zirconium polycationic compounds

It is shown that cerium dioxide hydrosols can be stabilized by polycationic compounds of zirconium, and the optimum conditions of the stabilization are determined. Stable CeO₂ hydrosols with concentrations of higher than 20 wt % are prepared; the sizes and electrophoretic mobility of their particles, as well as sol stability in the presence of some electrolytes, are investigated. The nature of the aggregation stability of the stabilized cerium dioxide sols is discussed.     

Synthesis of epoxy dinitriles from citral and their acid-catalyzed transformations

2,3-and 6,7-Epoxy derivatives of citral react with malononitrile in the presence of basic Csβ-zeolite to give the corresponding epoxyalkenylidenemalononitriles as the major products. Epoxy dinitriles obtained from 6,7-epoxycitral undergo acid-catalyzed transformations into tetrahydrofuran derivatives or acyclic polyenes containing hydroxy and cyano groups, depending on the catalyst nature.     

Acid-Catalyzed Rearrangements of (-)-Thujopsene

The transformations of (-)-thujopsene in liquid (HSO₃F-SO₂FCl) and over solid (TiO₂/SO₄ ^{2 -}) superacids, as well as by the action of peroxy acids, were studied. New tricyclic hydrocarbons were isolated. The experimental results were compared with the data of computer analysis of the most probable transformation pathways using molecular-mechanics and quantum-chemical methods.     

Harmonic Vibrations of a Viscoelastoplastic Sandwich Cylindrical Shell

The free and forced harmonic vibrations of viscoelastoplastic sandwich shells are analyzed. An equation for approximate determination of the amplitudes of near-resonance vibrations is derived. As an example, the problem is solved for a sandwich circular cylindrical shell     

Reactions of caryophyllene,isocaryophyllene, and their epoxy derivatives with acetonitrile under ritter reaction conditions

Acid-catalyzed reactions between acetonitrile and caryophyllene, isocaryophyllene, caryophyllene 4, 5-epoxide, and isocaryophyllene 4,5-epoxide affording optically active amides with a tricyclic skeleton were investigated.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1641–1646.Original Russian Text Copyright © 2004 by Yarovaya, Korchagina, Rybalova, Gatilov, Polovinka, Barkhash.     

Synthesis of copper(II) oxide hydrosols

A procedure is developed for the synthesis of copper(II) oxide hydrosols. It is shown that the main parameters that govern the reproducibility of the synthesis results and the aggregation stability of synthesized hydrosols are the temperature of copper(II) nitrate hydrolysis and the concentration of a peptizing agent. Dispersed phase particles are shown to have a cylindrical shape with a prevailing length-to-diameter ratio of approximately 2.7.     

Synthesis and Antiviral Properties of Camphor-Derived Iminothiazolidine-4-Ones and 2,3-Dihydrothiazoles

A set of heterocyclic products was synthesized from natural (+)-camphor and semi-synthetic (−)-camphor. Then, 2-Imino-4-thiazolidinones and 2,3-dihydrothiazoles were obtained using a three-step procedure. For the synthesized compounds, their antiviral activity against the vaccinia virus and Marburg virus was studied. New promising agents active against both viruses were found among the tested compounds.