Polyfuryl(aryl)alkanes and their derivatives 9. Polyfuryl(aryl)methanes in the diels-alder reaction

The reaction of polyfuryl(aryl)methanes with N-(3,5-dichlorophenyl)maleimide has been studied. It was found that tetrasubstituted methanes do not react. Difurylmethane, gem-difurylethane, gem-difurylethane, and trifurylmethane form mono- and diadducts, and difurylarylmethanes form only monoadducts. The molecular and crystal structure of the diadduct of gem-difurylethane- gem-bis {4-aza-7-methyl-10-oxa-4-(3,5-dichlorophenyl)tricyclo-[5,2,1,0 _2,6]deca-8-en-3,5-dion-1-yl}ethane has been studied.For Communication 8, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 751–758, June, 1993.     

Polyfuryl(aryl)alkanes and their derivatives. 14. Halochromism of polyfuryl(aryl)alkanes

It was concluded on the basis of the similarity between the electronic spectra of difurylarylmethanes and trifurylalkanes and the spectra of the corresponding arylfurylcarbinols and difurylcarbenium perchlorates in concentrated sulfuric acid that the appearance of color in the solutions of polyfuryl(aryl)alkanes in concentrated sulfuric acid results from their disproportionation at the carbon-carbon bond with the elimination of the furan ring. The disproportionation of difurylalkanes, containing a methine hydrogen atom at the central carbon atom, under these conditions is accompanied by hydride transfer.For Communication 13, see [1].Kubansk State Technological University, Krasnodar. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 738–741, June, 1996. Original article submitted February 21, 1996.     

Polyfuryl(aryl)alkanes and their derivatives. 4. Synthesis of furyldiarylmethane derivatives

A number of substituted furyldiarylmethanes were obtained by the reaction of furan derivatives with secondary aromatic alcohols.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 307–308, March, 1984.     

Polyfuryl(aryl)alkanes and their derivatives. 2. Trifurylalkanes and mechanism of their formation

Alkylfurans react with carboxylic acid anhydrides and chlorides in benzene in the presence of catalytic amounts of perchloric acid to give trifurylalkanes. The mechanism of the reaction, which is a consecutive process with the successive formation of an acylfuran, an alkyldifurylcarbinol, and a trifurylalkane, is examined. Intermediates, including an alkyldifurylcarbonium perchlorate, were isolated and characterized.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 592–596, May, 1983.     

Polyfuryl(aryl)alkanes and their derivatives 18. Photochemical transformation of 2-nitroaryldifurylmethanes

During UV irradiation or storage in light, solutions of 2-nitroaryldifurylmethanes in THF are converted into derivatives of 4,9-dihydrofuro[3,2-b]quinoline.For communication 17 see [1].Kubansk State Technological University, Krasnodar 350072, Russia. Severo-Osetinsk State University, Vladikavkaz 362040, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1250–1252, September, 1998.     

Polyfuryl(aryl)alkanes and their derivatives 16. Convenient path to benzofuran ketones

2-(3-Oxobutyl)-3-(5-methyl-2-furyl)benzofurans were synthesized by the recyclization of 2-hydroxyarylbis(5-methyl-2-furyl)methanes in methanol saturated with hydrogen chloride. They can also be obtained by the reaction of salicylaldehydes and sylvane in an ethanol solution of hydrogen chloride.For Communication 15, see [1].Severo-Osetinsk State University, Vladikavkaz, Russia. Kubansk State Technological University, Krasnodar 362040, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 603–607, May, 1998.     

Polyfuryl(aryl)alkanes and their derivatives. 12. C-fur bond cleavage in the series of polyfuryl(aryl)alkanes

Reactions taking place with cleavage of the C-Fur bond are examined. It was established that disproportionation in two directions, leading to the formation of tris(5-methyl-2 furyl)methane, takes place when 3, 4dimethoxyphenylbis(5-methyl-2 furyl)methane is boiled in an acidic medium. The acid-catalyzed reaction of 5-methylfurfural with ethylene glycol leads to the formation of either 2-(S-methyl-2 fury!)-1,3-dioxolane or tris(S-methyl-2 furyl)methane, depending on the catalyst. The treatment of 2-(S-methyl-2 fury!)-1,3-dioxolane or gem-tris(5. methyl-2 furyl)ethane with triryl perchlorate leads to tris(5-methyl-2 furyl)carbenium or bis(5-methyl-2-furyl)methylcarbenium perchlorates respectively.For Comminication 11, see [1]Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 175–179, February, 1996.     

Polyfuryl(aryl)alkanes and their derivatives. 5. Cations and radicals in the polyfuryl(aryl)methane series

The perchlorates of trifuryl- and difuryl(aryl)carbene have been prepared by the oxidation of polyfuryl(aryl)-methanes with trityl perchlorate and have been characterized. The temperature dependence of the PMR and ¹³C NMR spectra of the cations suggests that they exist in solution in the form of various rotamers. X-ray diffraction has been used to establish that the tris(5-methyl-2-furyl)carbene perchlorate molecule is a symmetrical propeller in which each furan ring is twisted from the plane by 10.4°. Reduction of the corresponding perchlorates on a zinc mirror in tetrahydrofuran gives stable polyfuryl(aryl)-methane radicals which were recorded by ESR spectroscopy.For Communication 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 329–337, March, 1993.     

Polyfuryl(aryl)alkanes and their derivatives. 10. Selective synthesis of 2-hydroxyaryldifurylmethanes

It was shown that Me₃SiCl, B(OH)₃, PhB(OH)₂, and B₂O₃ can act as catalysts for the selective synthesis of 2-hydroxyaryldifurylmethanes. It was established by x-ray crystallographic analysis that the molecules in the crystal of 2-hydroxy-3,5-diiodopenylbis(5-methyl-2 furyl)methane are linked in pairs by two hydrogen bonds between the hydroxyl group in one of them and the oxygen atom of the fury! group in the other.For Comunication 9. see [1]Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 162–167, February, 1996.     

Polyfuryl(aryl)alkanes and their derivatives. 17. Synthesis of compounds of the oxazulene series

Preparative methods were developed for the synthesis of various compounds of the benzofurooxazulene series. It was established that the formation of an oxazulenium salt and a dihydrooxazulene derivative during the treatment of 3-(5-methyl-2-furyl)-2-(3-oxobutyl)benzofurans with perchloric acid results from disproportionation of the intermediate compound—an oxazulene derivative.For Communication 16, see [1].Kubansk State Technological University, Krasnodar 350072, Russia. Severo-Osetinsk State University, Vladikavkaz 362040, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 883–892, July. 1998.     

Polyfuryl(aryl)alkanes and their derivatives. 7. New recyclization and cyclization reactions in the 2-hydroxyaryldifurylmethane series

Reaction of 2-hydroxybenzaldehydes with -methylfuran (sylvan) under acid-catalysis conditions was investigated. It is shown that the reaction does not stop at the step involving formation of 2-hydroxyarylfuryl-methanes but proceeds further with opening of one of furan rings and recyclization to 3-furylbenzo-furan derivatives. The latter in turn undergo transformations that lead to new heterocyclic systems — 5,6-dihydro-2,4-dimethyl-4-(5-methyl-2-furyl)-4H-benzo[b]furo[2,3-h]cyclopenta[b]furans. Data from the IR, PMR, and mass spectra, alternative synthesis, and x-ray diffraction analysis were used to confirm structures of the synthesized compounds.For Communication 6 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 616–626, May, 1993.     

Polyfuryl(Aryl)alkanes and their derivatives. 6. Stereochemistry of intramolecular rotations about the C-C+ bonds in aryl(Alkyl)difurylcarbonium ions

It was demonstrated by dynamic ¹H NMR spectroscopy that for difurylmethyl and gem-difurylethyl cations conformational changes are realized through rotation of one of the furan rings, whereas in the case of aryldifurylmethyl cations conformational transformations take place as the simultaneous rotation of two aromatic rings; the correlated rotation of the two furan rings proceeds with smaller energy expenditures.For Communication 5 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 450–455, April, 1993.     

Polyfuryl(aryl)alkanes and their derivatives. 11. Optimization of the conditions for the synthesis of 2-nitroaryldifurylmethanes and the nature of the side products

It was found that 2-nitroaryldifurylmethanes can be obtained with high yields as a result of the condensation of derivatives of 2-nitrobenzaldehyde and sylvane in dioxane in the presence of perchloric acid. The reaction of 6-nitroveratraldehyde and sylvane in benzene in the presence of trimethylsilyl chloride leads to the formation of the product from the condensation of the aryldifurylmethane with the initial aldehyde and also a derivative of fitful-2,1-benzisoxazole.For Communication 10, see [1]Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 168–174, February, 1996.     

Polyfuryl(aryl)alkanes and their derivatives. 13. Molecular structure of bis(5-methyl-2-furyl)(4-methoxyphenyl)methane and tris(5-methyl-2furyl)methane

4-Methoxyphenylbis(5-methyl-2-furyl)methane (I) and tris(5-methyl-2-furyl)methane (II) were investigated by x-ray crystallographic analysis. It was established that the molecules of (I) have a propeller conformation with C_s symmetry, and the furan rings are turned with the oxygen atoms towards the methine hydrogen atom. The molecule of (II) has a different conformation with C_2v symmetry; one of the furan rings and the methine C-H bond lie ideally in one plane, and the other two furan rings are arranged symmetrically with the oxygen atoms in relation to this bond and incline toward eclipsing of the exocyclic C-C bond.For Communication 12, see [1].Kubansk State Technological University, Krasnodar. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 648–653, May, 1996.     

Polyfuryl(aryl)alkanes and their derivatives. 8. Synthesis of benzofuro[2,3-h]-1-oxaazulenium salts. molecular and crystal structures of 2,4-dimethylbenzo[b]furo[2,3-h]-1-oxaazulenium perchlorate

The first representatives of a new heterocyclic system — benzofuro[2,3-h]-1-oxaazulenium salts — were synthesized. Diverse variations of the synthesis of these compounds are proposed. The molecular and crystal structures of 2,4-dimethylbenzo[b]furo[2,3-h]-1-oxaazulenium perchlorate were studied.See [1] for our preceding communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 627–632, May, 1993.     

Synthesis and optical activity of aryl(N-trifluoromethylsulfonylimino)thiodifluoroacetic acids and their derivatives

Synthesis and NMR studies of a new type of optically active sulfur(IV) compounds—aryl(N-trifluoromethylsulfonylimino)thiodifluoroacetic acids and their derivatives are described.     

Self-assembly of long chain alkanes and their derivatives on graphite

We combine scanning tunneling microscopy (STM) measurements with ab initio calculations to study the self-assembly of long chain alkanes and related alcohol and carboxylic acid molecules on graphite. For each system, we identify the optimum adsorption geometry and explain the energetic origin of the domain formation observed in the STM images. Our results for the hierarchy of adsorbate-adsorbate and adsorbate-substrate interactions provide a quantitative basis to understand the ordering of long chain alkanes in self-assembled monolayers and ways to modify it using alcohol and acid functional groups.     

Kinetics of oxidation of alkanes and their derivatives byn-decanepersulfonic acid

The kinetics of interaction ofn-decanepersulfonic acid with linear, branched, and substituted hydrocarbons was studied. The oxidation ofcyclo-C₆H₁₂/C₆D₁₂ occurs with a moderate kinetic isotope effect,k ^H/k ^D=2.2±0.3. A satisfactory correlation between the partial rate constants and the structure of hydrocarbons in terms of the Okamoto-Brown equation was found. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 822–825, May, 2000.