A problem of determining a special spatial part of 3D memory kernel in an integro‐differential hyperbolic equation

The inverse problem of determining 2D spatial part of integral member kernel in integro‐differential wave equation is considered. It is supposed that the unknown function is a trigonometric polynomial with respect to the spatial variable y with coefficients continuous with respect to the variable x. Herein, the direct problem is represented by the initial‐boundary value problem for the half‐space x>0 with the zero initial Cauchy data and Neumann boundary condition as Dirac delta function concentrated on the boundary of the domain . Local existence and uniqueness theorem for the solution to the inverse problem is obtained.     

Novel trialkylsilyl(germyl)-substituted thienyl- and furylbenzimidazoles and their N-substituted derivatives – synthesis,structure and cytotoxic activity

The reaction of 1,2-phenylenediamine with a variety of silicon- or germanium-containing 2-furaldehydes or 2-thienylcarbaldehydes in DMFA gave the corresponding benzimidazole derivatives in moderate yields (36–49%) in the presence of sodium hydrogen sulfite. As a result, a new series of silyl, germyl substituted hetarylbenzimidazoles were synthesized and their in vitro cytotoxicity was studied. The quaternisation of N-substituted benzimidazoles by heating with various alkyl, allyl and propargyl chlorides and bromides leads to the formation of benzimidazolinium salts. Potential cytotoxic activity of synthesized new benzimidazoles and benzimidazolinium salts was tested in vitro on two monolayer tumour cell lines: MG-22A (mouse hepatoma), HT-1080 (human fibrosarcoma) and normal mouse fibroblasts (NIH 3T3) and compared with corresponding benzimidazoles.     

Synthesis and Cytotoxic Activity of 1‐{3‐[1‐(5‐Organylsilylfuran‐2‐yl)silinan‐1‐yl]propyl}amines and Some Trimethylgermyl Analogues

New highly cytotoxic 1‐{3‐[1‐(5‐organylsilyl‐furan‐2‐yl)silinan‐1‐yl]propyl}amines and some trimethylgermyl analogues (IC₅₀ 1–7 μg mL^?1) have been synthesized by a hydrosilylation reaction of aliphatic and heterocyclic N‐allylamines in the presence of Speier’s catalyst. The effects of the silacycle, the element‐organic substituent in position 5 of the furan ring, and the structure of the amine on the cytotoxicity of the new compounds have been studied.     

Pumping of electromagnetic energy via multiple total internal reflection from active media

An experiment for strong light amplification at multiple total reflections from active gaseous media is proposed.     

Ferrocenylalkyl azoles: bioactivity,synthesis, structure

The toxicity of ferrocenylethyl benzotriazole ( 1 ) and other ferrocene compounds including ferrocenylmethyl benzimidazoles ( 4,5,6,11 ), ferricenium salts ( 3,9,10 ) and ferrocenylmethyl adenine ( 7 ), was studied. All ferrocene complexes under investigation showed low or medium toxicities. On the basis of an earlier model of chemical carcinogenesis, the antitumor activity of ferrocenylalkyl azoles 1, 8 and ferricenium salts 9, 10 was studied in vivo in the so‐called sub‐capsular test on human tumors. This effectiveness was compared with that of cisplatin. A series of ferrocenylalkyl azoles were synthesized by interacting azoles either with α‐hydroxyalkyl ferrocenes FcC(OH)R₁R₂ in organic solvent in the presence of aqueous HBF₄ in quantitative yields or with trimethyl(aminomethyl)ferrocene iodide in an aqueous‐basic medium in good yields. The X‐ray determinations of molecular and crystal structures of α‐(1‐benzotriazolyl)ethylferrocene ( 1 ) and α‐(1‐naphthatriazolyl)ethylferrocene ( 12 ) were performed. Copyright © 2008 John Wiley & Sons, Ltd.     

Interaction of secondary amines with aromatic aldehydes-efficient method for synthesis of the functionalized heterocyclic amines

A method is proposed for the benzylation of secondary heterocyclic amines with functionalized derivatives of benzaldehyde in the presence of formic acid under conditions close to amination according to the Leuckart-Wallach reaction. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1820–1823, December, 2007.     

Pyrazolyc 3-hydroxychromones: Regulation of ESIPT reaction by the “flavonol-like” intramolecular hydrogen bonding to carbonyl group oxygen,which dominates over the “alternative” H-bond to heterocyclic nitrogen

Two isomeric pyrazole derivatives of 3-hydroxychromone (3HC) with and without the possibility of the multiple intramolecular hydrogen bonds formation were compared theoretically and experimentally with the aim to find out whether the excited state intramolecular proton transfer (ESIPT) reaction follows the traditional to the most of 3HCs “flavonol-like” direction towards the CO group oxygen or an “alternative” direction towards the heterocyclic nitrogen atom.Quantum-chemical modeling and comparative study of the experimental spectral parameters of the title compounds indicated the preferential realization of “flavonol-like” ESIPT to oxygen channel.The 3HC systems with the “alternative” intramolecular hydrogen bond to nitrogen were characterized as low fluorescent and practically unable to ESIPT with participation of the nitrogen containing heterocyclic unit.     

Crystallographic report: 2‐Furfurylgermatrane

The germanium atom is penta‐coordinated and adopts a trigonal bipyramidal geometry. The 2‐furfuryl group and the nitrogen atom each occupy an apical position with a transannular N→Ge bond distance of 2.173(3) Å. Copyright © 2004 John Wiley & Sons, Ltd.     

Structural anisotropy study by resonance Raman scattering in nematics with different dyes

The method for the structural anisotropy determination, which is based on a comparison of the degree of polarization of absorption and resonance Raman bands, is tested with three dyes having different molecular dimensions in one nematic liquid crystal. The experimentally observed correlation between the variation of the structural anisotropy factor and the order parameters deviates from the predictions of the Segre model. This method could also be applied to determine the local field anisotropy for liquid crystals, but we must take into account the observed dependence of the structural anisotropy on the dimensions of the probe molecules.