Study of the mechanism of recyclization of furans into thiophenes and selenophenes in conditions of acid catalysis. 4. study of the effect of the solvent and direction of reactions of hydrolysis and recyclization of 2,5-dimethylfuran

The kinetics of hydrolysis of 2,5-dimethylfuran and its recyclization into the corresponding thiophene were investigated in water-alcohol medium W R I and 50% ethyl alcohol in the presence of HCl. It was found that the rates of these reactions are a function of both the initial concentration of the acid component and the concentration of water in the alcohol. The rate of hydrolysis is a function of the dilution of the alcohol to a greater degree than the rate of recyclization.See [1] for Communication 3.Scientific-Research Institute of Chemistry at N. G. Chernyshevskii Saratov State University, Saratov 410026. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 624-628, May, 1995. Original article submitted January 30, 1995.     

Three-body treatment of Coulomb effects in the problem of long-range effective interactions

The problem of Coulomb scattering of a charged particle by a two-particle bound system, consisting of a charged and a neutral particle, is investigated in the integral-equation approach of rigorous three-body theory. The bound state of the two particles is provided by a short-range interaction chosen in the simplest form using anS-wave separable potential. The integral equation defining the effective potential of the interaction of the charged particle with the two-particle bound system is formulated. It is shown that the multiple Coulomb scattering of the involved charged particles generates a sequence of long-range terms in the effective potential. It turns out that the long-range effects of Coulomb scattering are partly cancelled. As a result the polarization potential does not contain the longest-ranged terms which decrease at large distances as ^–2 and ^–3.     

Luminescent determination of automobile petrol in hexane solutions

The work deals with the problem of determination of automobile petrol of various octane numbers and petroleum contamination of some objects on the basis of analysis of photoluminescence spectra of automobile petrol samples. For this purpose steady state luminescence properties of samples of automobile petrol of different types being in sale were measured. Samples of automobile petrol diluted in hexane were prepared and their luminescence spectra were measured at room and liquid nitrogen temperatures of samples. We constructed concentration dependences of luminescence intensity of both wide band luminescence of liquid solutions obtained at room temperature and peak intensities of luminescence lines of quasi linear spectra of solutions frozen at 77 K. Possibility to use luminescence method for analysis of petrol pollutions on some objects is illustrated by results of investigation of pine-wood pieces contaminated by automobile petrol.     

Synthesis and some transformations of 4H-pyrano[3,2-d]pyrazoles

The ability of the amide carbonyl group of the pyrazolone ring to participate in the heterocyclization of oxopropyl-5-pyrazolones under the influence of polyphosphoric acid (PPA) or phosphorus polysulfide in dioxane with the formation of 4H-pyrano[ 3,2-d]pyrazole derivatives is demonstrated. Ionic hydrogenation of the pyranopyrazoles leads to 5,6-dihydropyrano[3,2-d]pyrazoles, while the action of phosphorus polysulfide in xylene leads to pyrazolo[5,4-b]thiapyrylium salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 317–320, March, 1982.     

Reactions of 4H-selenopyrans with halogens

The reactions of 2,4,4,6-tetraphenyl-4H-selenopyran with chlorine or bromine give the corresponding 1,1-dichloro- or 1,1-dibromo-4H-selenopyrans, whereas the reaction of 2,4,6-triphenyl-4H-selenopyran with bromine gives 2,4,6-triphenylselenopyrylium tribromide.     

Properties and antiphage activity of condensed hydro(thio)chromans and their copper complexes

Research into the reactivity of carbonyl-substituted spirohydrochromans with hydrogen sulfide under the influence of protic and aprotic acids was continued for the case of 3,4,5,6,7,8-hexahydrospiro[chromene-2,1-cyclohexan]-2-one. The general nature of the reactions was established. Complexes of copper(II) with substituted hydro(thio)chromans were obtained. The results from investigation of the antiphage activity of the synthesized compounds are presented.N. G. Chernyshevskii Saratov State University, Saratov. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1320–1325, October, 1996. Original article submitted April 18, 1996; revision submitted August 13, 1996.     

Configuration and conformation of 3,5-diphenyl-2-thiabicyclo[4.4.0]decane

The PMR spectra of 3,5-diphenyl-2-thiabicyclo[4.4.0]decane and its 4,6-dideutero derivative and S-oxide in the presence of Eu(dpm)₃ were studied. It was established that 3,5-diphenyl-2-thiabicyclo[4.4.0]decane has a cis,cis,cis configuration. The extremal spin-spin coupling constants (SSCC) constitute evidence for conformational rigidity of the investigated condensed system, which exists in the form of a puckered chair. The formation of the same cis,cis,cis isomer of 3,5-diphenyl-2-thiabicyclo[4.4.O]decane in the case of catalytic hydrogenation, disproportionation with trifluoroacetic acid, and ionic hydrogenation constitutes evidence for stereospecificity of the processes involving the reduction of the double bonds in 2,4-diphenyl-5,6-tetramethylene-6H-thiopyran.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1347–1350, October, 1981.     

The oxidation reactions of thiopyrans

A method was developed for the preparation of compounds with 4H-thiopyrone structure by the oxidation of the corresponding 4H-thiopyranes and their condensed analogs by potassium permanganate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1489–1492, November, 1985.     

Synthesis of hydrothioxanthenes. III

Reaction of alkylidenedicyclohexanones with hydrogen sulfide in polar solvents under the influence of hydrogen chloride or hydrochloric acid has been studied. A preparative route to the synthesis of sym-octahy-drothioxanthenes has been established and some of their chemical properties have been studied.For part II, see [1].