A new method for the synthesis of silicon-and germanium-containing 2-acetylfurans and 2-acetylthiophenes

A new method was developed for the synthesis of silicon-and germanium-containing acetylfurans and acetylthiophene by metallation of 2-acetylfuran or 2-acetylthiophene with n-BuLi at low temperature after protection of the carbonyl group with lithium N-methylpiperazide and reaction of the lithium derivative with various trialkyl-, alkylphenyl-, and cycloalkylchlorosilanes or trialkylchloro(bromo)germanes. The cytotoxic activity of the new compounds was studied, and it was established that the silicon-and germanium-containing acetylfurans and acetylthiophenes are substances with low toxicity (LD₅₀ 312->2000 mg/kg) and have low cytotoxicity toward HT-1080 and MG-22A tumor cells. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 192–199, February, 2007.     

Irradiation of detonation nanodiamonds with γ-rays does not produce long living spin radicals

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Polyureas—a new promising class of binders for adhesives, sealants, and coatings

The results of an investigation of the dependences of the gelation time of polyurea composites on various factors are presented. Examples of reducing the gelation time of a polyurea-based sealant for practical applications are shown. Methods of creation of polyurea composites with predefined technological properties are suggested.     

A two-dimensional inverse problem for the viscoelasticity equation

For the integrodifferential equation that corresponds to the two-dimensional viscoelasticity problem, we study the problem of determining the density, the elasticity coefficient, and the spaceintegral term in the equation. We assume that the sought functions differ from the given constants only inside the unit disk D = {x ∈ ?² | |x| < 1}. As information for solving this inverse problem, we consider the one-parameter family of solutions to the integrodifferential equation corresponding to impulse sources localized on straight lines and, on the boundary of D, there are defined the traces of the solutions for some finite time interval. It is shown that the use of a comparatively small part of the given information about the kinematics and the elements of dynamics of the propagating waves makes it possible to reduce the problem under consideration to three consecutively and uniquely solvable inverse problems that together give a solution to the initial inverse problem.     

Exact bounded boundary controllability of vibrations of a two-dimensional membrane

The boundary control of vibrations of a plane membrane is considered. A constraint is imposed on the absolute value of the control function. The goal of the control is to drive the membrane to rest. The proof technique used in this paper can be applied to a membrane of any dimension, but the two-dimensional case is considered for simplicity and illustrative purposes.     

Transformation of optical vortices by polarization dynamic holograms

Results of theoretical and experimental studies of regularities in the transformation of the topological and polarization structures of optical vortices by polarization dynamic holograms formed by pulse Gaussian and singular light beams in dye solutions are presented.     

Fused Fluorinated Bis-β-diketones and Luminescent-Spectral Properties of Their Complexes with Europium

Russian Journal of General Chemistry - Claisen condensation of diacetylated fused aromatic and heteroaromatic compounds (fluorene, dibenzofuran, dibenzothiophene, or carbazole) with...     

One-Pot Synthesis of Quaternary Phosphonium Salts Based on Tertiary Phosphines and (R)-(+)-Pulegone

Russian Journal of General Chemistry - As a result of reactions of nucleophilic addition of tertiary phosphines to pulegone in the presence of hydrochloric acid, quaternary phosphonium salts were...