Reactions of 1,2,4,5-Tetrafluoro-3,6-bis(vinylsulfonyl)benzene with Cyclic Amines

Reactions of 1,2,4,5-tetrafluoro-3,6-bis(vinylsulfonyl)benzene with pyrrolidine, piperidine, and morpholine lead to formation of different products, depending mainly on the reactant ratio. In the presence of 2 equiv of cyclic amine, adducts at both vinylsulfonyl groups are formed, while in reactions with 4 equiv of cyclic amine, the addition at the double bonds is accompanied by nucleophilic replacement of one or two fluorine atoms in the benzene ring.     

Contribution of the pyrylium structure to the electrochemical properties of nitroflavones

The polarographic behavior of 3- and 4-nitroflavones on a dropping mercury electrode in Britton-Robinson buffer solutions was investigated. It Is shown that, depending on its position, the nitro group displays properties that are typical only for aromatic nitro compounds or a combination of properties of aromatic and aliphatic -unsaturated nitro compounds. The deciding factor is the realization of pyrylium and pyrone structures, depending on the pH of the medium. The kinetic parameters of the chemical transformation of the nitro form to the aci form of 3-nitroflavone in an alkaline medium are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 312–316, March, 1982.     

Study of Dieckmann’s equation with integral kernels having variable kurtosis coefficient

An integral equation arising in a spatial model of stationary communities developed by the Austrian scientists Ulf Dieckmann and Richard Low is studied. A special case of this equation with integral kernels being Student distributions is considered. The existence of a solution in this case is proved, and the application of a method for reducing the dimension of a multidimensional integral equation previously proposed by the authors is described.     

Experimental study of electron density distribution in crystals of antimony(V) dicarboxylate complexes

Structural Chemistry - The molecular structure and charge density distribution in the crystals of triphenylantimony bis[(2E)-3-phenylprop-2-enoate] [Ph3Sb(O2CCH=CHPh)2] and triphenylantimony...     

Unusual transformations of difluorosilanone F<Subscript>2</Subscript>Si=O

The structure and properties of fluorosilicon polymer (fluorosil) formed by the reaction of phenyltrifluorosilane with aliphatic alcohols have been studied by the methods of IR, ¹⁹F, ²⁹Si NMR spectroscopy, high temperature mass-spectrometry, derivatography and atom emission analysis. Due to its high reactivity, this polymer readily reacts with glass of the reaction vessel extracting the ions of all metals entering into its composition. Fluorosil formed in a quartz, teflon or polypropylene reactors is characterized by low stability and is slowly decomposed to SiF₄ and SiO₂. Apparently, fluorosil is the product of incorporation of SiF⁴ into the SiO₂ matrix.     

Comparative analysis of the thickness and electrical conductivity of thin chalcogenide semiconductor films

The structure and thickness of zinc and cadmium chalcogenide semiconductor films are studied by X-ray radiography. The film thickness is shown to be comparable with the half-value layer depth. The electrical conductivity of the films increases upon heating in the hydrogen atmosphere and decreases upon heating in carbon oxide. The opposite trend is observed in the ratio between the electrical conductivity and band gap of the initial and oxidized film surfaces.

     

Light-induced formation of nitroxyl radicals by organic Bi(V) compounds in the presence of 2-methyl-2-nitrosopropane and <Emphasis Type="Italic">C</Emphasis>-phenyl-<Emphasis Type="Italic">N</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-butylnitrone

The organic bismuth compounds Ph₃Bi(O₂CCH=CHCH₃)₂ and Ph₃Bi(O₂CEt)₂ decompose under scattered light in the presence of spin traps (2-methyl-2-nitrosopropane and C-phenyl-N-tert-butylnitrone) in organic solvents (acetonitrile, benzene, toluene) to form adducts of phenyl radicals with the traps.     

Anti-Proliferative and Cytoprotective Activity of Aryl Carbamate and Aryl Urea Derivatives with Alkyl Groups and Chlorine as Substituents

Natural cytokinines are a promising group of cytoprotective and anti-tumor agents. In this research, we synthesized a set of aryl carbamate, pyridyl urea, and aryl urea cytokinine analogs with alkyl and chlorine substitutions and tested their antiproliferative activity in MDA-MB-231, A-375, and U-87 MG cell lines, and cytoprotective properties in H₂O₂ and CoCl₂ models. Aryl carbamates with the oxamate moiety were selectively anti-proliferative for the cancer cell lines tested, while the aryl ureas were inactive. In the cytoprotection studies, the same aryl carbamates were able to counteract the CoCl₂ cytotoxicity by 3–8%. The possible molecular targets of the aryl carbamates during the anti-proliferative action were the adenosine A2 receptor and CDK2. The obtained results are promising for the development of novel anti-cancer therapeutics.     

Novel method for preparing 4-haloquinoline N-oxide hydrohalides from 4-nitroquinoline N-oxide

A simple method has been developed for preparation of 4-haloquinoline N-oxide hydrohalides involving passage of the gaseous hydrohalide at room temperature through a solution of 4-nitroquinoline N-oxide in chloroform.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 516–518, April, 1996.     

Reaction of Dithiomalonamide and Dianilide with α-Acetylene Ketones

Russian Journal of Organic Chemistry -