Novel purine conjugates with N-heterocycles: synthesis and anti-influenza activity

Chemistry of Heterocyclic Compounds - A number of novel amides were synthesized by coupling of 6-[(9H-purin-6-yl)amino]hexanoic acid to heterocyclic amines. The antiviral activity of the obtained...     

Propagation,Dispersion, and Localization of Elastic Waves in Low-Symmetric Anisotropic Waveguides

The results of a theoretical investigation into ultrasonic linear normal wavefields in anisotropic three-dimensional bodies with mechanical orthorhombic symmetry are presented. A detailed study is made of the dispersion dependencies for higher normal wave modes in a single-layered orthorhombic plate-type waveguide. Moreover, the distribution of complex branches corresponding to the edge standing wave modes is studied and their role in the transformation of the entire spectrum upon a change in the travel direction in the waveguide plane is analyzed. A new type of localization of the higher modes of high-frequency short-range normal waves in a crystal layer is described. An efficient method is developed for studying the spectrum of ultrasonic normal waves in a circular cylindrical waveguide made of an orthorhombic monocrystal     

Dispersion of normal waves in a linearly orthotropic circular cylinder with a clamped lateral surface

We propose a method of obtaining the dispersion equation for normal waves in an orthotropic cylinder from the boundary conditions on the rigidly clamped boundary using a system of exponential particular solutions of the three-dimensional equations of its stationary wave motions. We compute the real and imaginary branches of the dispersion spectrum for a waveguide made of monocrystalline strontium sulfate. On figure. Bibliography: 7 titles. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 26, 1996, pp. 96–99.     

Synthesis,Anti-Influenza H1N1 and Anti-Dengue Activity of A-Ring Modified Oleanonic Acid Polyamine Derivatives

A series of sixteen A-ring modified (2,3-indolo-, 2-benzylidene) oleanonic acid derivatives, holding some cyclic amines, linear polyamines and benzylaminocarboxamides at C28, has been synthesized and screened for antiviral activity against influenza A/PuertoRico/8/34 (H1N1) and Dengue virus serotypes of DENV-1, -2, -3, -4. It was found that 28-homopiperazine 2 and 3-N-phthalyl 22 amides of oleanonic acid demonstrated high potency with selectivity index SI 27 (IC₅₀ 21 μM) and 42 (IC₅₀ 12 μM). Oleanonic acid aminoethylpiperazine amide 6 and C-azepano-erythrodiol 23 appeared to be the most effective compounds against DENV-1 (IC_50′s 67 and 107 μM) and -2 (IC_50′s 86 and 68 μM correspondingly) serotypes.     

The critical frequencies of propagating waves in linearly isotropic cylindrical waveguides

We obtain the equations for determining the critical frequencies of normal waves with zero wave numbers and study them. We present the results of computation of the critical frequencies for a waveguide made of monocrystalline strontium sulfate, and also the results of a study of the variation of the critical frequencies with the generalized index of shear anisotropy for waves characterized at the critical frequencies by the longitudinal elastic displacements alone. Two figures. Bibliography: 8 titles. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 26, 1996, pp. 87–95.     

Differaction of plane deformation waves on a cylindrical cavity in an anisotropic bulk composed of a monoclinic system

An analytic-numerical method based on perturbations in the elastic moduli is proposed for solving problems involving the diffraction of two-dimensional longitudinal-shear harmonic deformation waves on a cavity with a smooth curvilinear cross section in an elastic medium with an anisotropy corresponding to a monoclinic system in the dynamic deformation plane. Results from a numerical analysis of the distribution of the dynamic stresses in the near diffraction field are presented for the case of longitudinal waves scattered on a dome-shaped cavity as the direction of the incident wave and the degree of anisotropy of the medium are varied. Donetsk State University. Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 30, pp. 137–147, 1999.     

Methods of Synthesis and Antiviral Activity of New 4-Alkyl-3-Nitro-1,4-Dihydroazolo[5,1-c][1,2,4]Triazin-4-ols

Chemistry of Heterocyclic Compounds - An azo coupling reaction of α-nitro ketones with 5-diazoazoles was used to obtain 4-alkyl-3-nitro-1,4-dihydroazolo[5,1-с][1,2,4]triazines, which...     

Discovery of New Ginsenol-Like Compounds with High Antiviral Activity

A number of framework amides with a ginsenol backbone have been synthesized using the Ritter reaction. We named the acetamide as Ginsamide. A method was developed for the synthesis of the corresponding amine and thioacetamide. The new compounds revealed a high activity against H1N1 influenza, which was confirmed using an animal model. Biological experiments were performed to determine the mechanism of action of the new agents, a ginsamide-resistant strain of influenza virus was obtained, and the pathogenicity of the resistant strain and the control strain was studied. It was shown that the emergence of resistance to Ginsamide was accompanied by a reduction in the pathogenicity of the influenza virus.     

Erosion processes in anthropogenic systems in the South of the Russian Far East

The results of studying erosion processes in anthropogenic systems in the South of the Russian Far East are given. The surface of tailings dumps has been shown to be subjected to not only air and wind but also chemical erosion, which creates a great hazard to the environment and human health. A direct relation has been found between the anthropogenic material discharge and precipitation amount. Its maximal value during intense erosion processes has been estimated. A set of measures has been proposed to reduce the impact of erosion processes in mining anthropogenic systems.     

Synthesis and Antimycobacterial Activity of Hydrazides Based on Pyridoxine Derivatives

Pyridoxine derivatives, 3-hydroxy-2-methylpyridine-4- and -5-carbohydrazides, were synthesized according to optimized known procedures, and a method for the synthesis of 5-(hydroxymethyl)-2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine-6-carbohydrazide was developed. The hydroxymethyl groups in positions 5 and 6 of 2,2,8-trimethyl-4H-[1,3]dioxino[4,5-c]pyridine showed different reactivities, and only the 6-hydroxymethyl group was selectively oxidized to aldehyde under mild conditions. The lactone ring in 5,6-dihydrofuro[3,4-b]pyridin-7(5H)-one was found to be stable to nucleophiles. The synthesized hydrazides showed no antimycobacterial activity.