1-Bromo-2-trifluoroacetylcyclobutenes as novel building blocks for the construction of trifluoromethyl substituted heterocycles. Part 2: Synthesis of trifluoromethyl substituted thiophenes, condensed with cyclobutene moieties

This paper describes a novel synthetic approach to 2-cyano-3-trifluoromethylthiophenes fused with cyclobutene rings with variable spiro conjunctions. The reaction of substituted 1-bromo-2-trifluoroacetylcyclobutenes with mercaptoacetonitrile results in the substitution of bromine with S-center to afford the corresponding nitriles in high yields, which form the target thiophenes by subsequent treatment of lithium 2,2,6,6-tetramethylpiperidide and acetic anhydride.     

Natural mineral sorbents for chemical and microbiological purification of potable water

The role of a number of rocks (shungite, glauconite fossil rock, flint) in a chemical and microbiological purification of water was estimated. On the basis of a shungite-dolomite module a simple method for a widescale manufacture of chemically and microbiologically pure potable water with conditionated content of mineral matters was developed.     

Addition reactions of 1,1,1-trifluoro-4-trimethylstannylbut-3-yn-2-one and 1,1,1-trifluorobut-3-yn-2-one to some tetrahydropyridines. Synthesis of trifluoroacylated polysubstituted tetrahydroazocines

A reaction of tetrahydropyridines, obtained by the Diels-Alder reaction from α,β-unsat-urated N,N-dimethylhydrazones and methyl acrylate, with acetylenes activated with the trifluoroacetyl group has been studied and found to lead to polysubstituted trifluoroacylated tetrahydroazocines. No cyclobutene intermediates have been detected.     

3-Indolizin-2-ylquinoxalines and the derived monopodands

The reactions of 3-acetylquinoxalin-2-one with methyl-and benzylpyridines in the presence of iodine produce the corresponding 3-(2-alkylpyridinioacetyl)quinoxalin-2(1H)-one iodides. Treatment of the latter with triethylamine affords the corresponding 3-indolizin-2-ylquinoxalin-2-ones. Due to the presence of the endocyclic carbamoyl group, the reactions of these compounds with bisalkylating reagents give quinoxaline-containing monopodands and monoalkylation products containing spacers with different lengths and of different nature. Dedicated to Professor Ya. A. Levin on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2534–2542, November, 2005.     

Development of a Radioastronomical Correlation Method for Measuring Mirror-Antenna Parameters

We consider the techniques and instrumentation developed at the Radiophysical Research Institute (NIRFI) for measuring mirror-antenna parameters using signals from extraterrestrial radio sources and geostationary satellites. The results of measuring the radiation patterns of several large-scale fully-rotatory radio telescopes in a wide dynamic range and of retrieving the amplitude and phase distributions on their apertures are presented.     

Synthesis of 1-tert-butyl-2-aryldiazene-2-oxides by reactions of t-BuNHMgBr with nitrobenzenes

A new method has been developed for the synthesis of alkylaryldiazene oxides by the reactions of t-BuNHMgBr with nitrobenzenes. The cis-azoxy compound 1-tert-butyl-2-(2-chlorophenyl)diazene-2-oxide, which irreversibly isomerizes to the trans isomer upon heating, was obtained for the first time under chemical reaction conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1394–1397, June, 1991.     

Effect of the isotope composition and unsaturated bonds on the mass defect spectrum of residual hydrocarbons

By accurately measuring the position of the peaks in the ion mass spectrum of residual gases, it is found that the peaks are associated with hydrocarbon ions. The “mass defect” spectrum is close to that obtained analytically. The deviations observed are related to the presence of the ¹³C isotope and nonsaturation of bonds in the ions recorded. The experimental data obtained may be used as a reference in impurity microanalysis, in calibrating the mass scale of mass spectrometers, and in checking the theory of mass spectrum analysis.