Variation of Functional Composition of SKEPT Rubber in the Course of Ozonolysis

Ozonolysis in hexane of ternary ethylene-propylene rubber (SKEPT), accompanied by formation of oxygen-containing groups and intermolecular cross-linking, was studied. These processes become more pronounced when ozonolysis is performed in hexane containing pyridine.     

Ferrocene‐modified thiopyrimidines: synthesis,enantiomeric resolution,antitumor activity

Ferrocenylalkyl thiopyrimidines ( 6a–d to 9a–d ) were prepared via the reaction of the α‐(hydroxy)alkyl ferrocenes, FcCHR(OH) ( 1a–d ; Fc = ferrocenyl; R = H, Me, Et, Ph), with 2‐thiopyrimidines ( 2 – 5 ) in acetone at room temperature in the presence of TFA, yielding 50–95%. The resulting enantiomers were resolved using HPLC on modified cellulose as chiral selector. The antitumor activities of S‐ferrocenylethyl 2‐thiopyrimidine ( 6b ) against two murine solid tumor models, carcinoma 755 (Ca755) and Lewis lung carcinoma (LLC) were evaluated in vivo. The strong antitumor effect of compound 6b on Ca755 and LLC was demonstrated. The index of tumor growth inhibition on Ca755 equaled 95% in comparison with control. Copyright © 2010 John Wiley & Sons, Ltd.     

Generation of Nonstationary Waves by a Spherical Piezoelectric Transducer Filled with a Viscous and Surrounded by a Perfect Compressible Liquids

A nonstationary problem is solved for a thin-walled piezoelectric transducer generating waves. The transducer is filled with a viscous and surrounded by a perfect compressible liquids. A method is developed to reduce this problem to a system of Volterra's integral equations. Calculations are performed to evaluate the effect of the viscous properties of the filler on the processes in the hydroelectroelastic system.     

Synthesis of New Bicyclic Phosphoranes by Cycloaddition Reactions

Abstract

Dialkyl alkynylphosphonites (I) react with nitrile of trimethylpyruvic acid, and esters of trifluoropyruvic and mesoxalic acids in boiling benzene to form new bicyclic phosphoranes. The reaction proceeds according to the scheme including the formation of bipolar ions (A) and (B), and ylide (C). Addition of the second molecule of carbonyl compound leads to (I).     

Synthesis of Tetraazide Derivatives of <Emphasis Type="Italic">p-tert</Emphasis>-Butylcalix[4]arene Using Copper-Catalyzed Nucleophilic Aromatic Substitution

Aromatic azido derivatives of p-tert-butylcalix[4]arene have been obtained for the first time using copper-catalyzed nucleophilic aromatic substitution of azide anion for bromide in 5,11,17,23-tetrabromo- 25,26,27,28-tetrabuthoxycalix[4]arene in a dioxane–water (3: 1) solvent mixture with N,N-dimethylethylenediamine as a stabilizing ligand for copper(I). When the reaction is carried out under with microwave heating, partial substitution products (mono-, distally di-, proximally di-, and trisubstituted) can be isolated in satisfactory yields.     

α,β-Unsaturated Derivatives of Trivalent Phosphorus in Reactions with Activated Carbonyl Compounds

Abstract

Dialkyl alkynylphosphonites (I) react with esters and nitriles of α-oxocarboxylic acids to give phosphorylated alkanoates, 1,3,2-dioxaphospholanes and l-phosphabicyclohept-4-enes, depending on the nature of the reagent and conditions of the reaction. The reaction of dialkyl alkenylphosphonites (II) with esters and nitriles of α-oxocarboxylic acids predominantly leads to dioxaphospholane derivatives.     

Radiation of nonstationary waves by a thin-walled piezoceramic cylinder containing a viscous compressible fluid

The transient operation conditions of a thin-walled piezoradiator containing a viscous compressible fluid and immersed into an acoustic medium are considered. The problem is solved using the integral Laplace time transformation. Originals of the general solution of the linearized Navier-Stokes equations are constructed for the interior of the domain. These originals are used to find the unknowns from a system of integral Volterra equations. Numerical examples are presented. S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 35, No. 12, pp. 63–71, December, 1999.     

Features of self-organization and biological properties of solutions of citric and succinic acids in low concentrations

Russian Chemical Bulletin - A relationship between the nonmonotonic concentration dependences of the size of the dispersed phase (nanoassociates), physicochemical properties (electric conductivity,...     

Stability of Oligomeric α-Alkoxyhydroperoxides

The thermal decomposition of oligomeric -alkoxyhydroperoxides (I) is described by a first-order rate law and characterized by an activation energy equal to 19.7 kJ/mol. A chain mechanism and a rate law for this reaction are proposed. The effect of amine and phenolic stabilizers on decomposition is studied, the efficiency of phenolic stabilizers is examined, and the effective rate constant of the acid-catalyzed decomposition of compounds I is determined.