Thiopyran

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Hooshang Pirelahi - One of the best experts on this subject based on the ideXlab platform.

  • effects of electron withdrawing group on the photoisomerization of tetraaryl 4h Thiopyran 1 1 dioxides
    Heteroatom Chemistry, 2008
    Co-Authors: Farnaz Jafarpour, Fatemeh Ramezani, Hooshang Pirelahi
    Abstract:

    Syntheses and photoisomerization of the new sulfone derivatives, 4,4-di (p-trifluoromethylphenyl)-2,6-diphenyl-4H-Thiopyran-1, 1-dioxide and 4-(p-trifluoromethylphenyl)-2,4,6-triphenyl-4H-Thiopyran-1,1-dioxide, have been investigated. The relative molar ratios of the photoproducts are compared with those of 2,4,4,6-tetraphenyl-4H-Thiopyran-1,1-dioxide as well as electron-donating substituted 4-methyl-2,4,6-triaryl-4H-Thiopyran-1,1-dioxides as model compounds under identical experimental conditions using 1H NMR spectroscopy. The results observed are discussed on the basis of a triplet excited state di-π-methane rearrangement. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:557–561, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20455

  • Effects of electron‐withdrawing group on the photoisomerization of tetraaryl‐4H‐Thiopyran‐1,1‐dioxides
    Heteroatom Chemistry, 2008
    Co-Authors: Farnaz Jafarpour, Fatemeh Ramezani, Hooshang Pirelahi
    Abstract:

    Syntheses and photoisomerization of the new sulfone derivatives, 4,4-di (p-trifluoromethylphenyl)-2,6-diphenyl-4H-Thiopyran-1, 1-dioxide and 4-(p-trifluoromethylphenyl)-2,4,6-triphenyl-4H-Thiopyran-1,1-dioxide, have been investigated. The relative molar ratios of the photoproducts are compared with those of 2,4,4,6-tetraphenyl-4H-Thiopyran-1,1-dioxide as well as electron-donating substituted 4-methyl-2,4,6-triaryl-4H-Thiopyran-1,1-dioxides as model compounds under identical experimental conditions using 1H NMR spectroscopy. The results observed are discussed on the basis of a triplet excited state di-π-methane rearrangement. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:557–561, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20455

  • An approach to the novel stereoselectivity in photorearrangement of 4,4-dialkyl-2,6-diphenyl-4H-Thiopyran-1,1-dioxides
    Journal of Photochemistry and Photobiology A-chemistry, 2006
    Co-Authors: Farnaz Jafarpour, Hooshang Pirelahi
    Abstract:

    The photochemical behaviour of 4,4-dimethyl-, 4-tert-butyl-4-methyl- and 4-benzyl-4-methyl-2,6-diphenyl-4H-Thiopyran-1,1-dioxides has been investigated and compared with those of 4-methyl-2,4,6-triphenyl-4H-Thiopyran-1,1-dioxide and 2,4,4,6-tetraphenyl-4H-Thiopyran-1,1-dioxide as model compounds under identical experimental conditions followed by 1H NMR spectroscopy. The high yields of the stereoisomeric bicyclic photoproducts of dialkyl analogues in the absence of SO2 extruded byproducts are discussed on the basis of a vinyl–vinyl di-π-methane (DPM) rearrangement.

  • The Effects of the Electron-Donating Methoxy Group on the Photoisomerization of 4-Methyl-2,4,6-triaryl-4H-Thiopyran-1,1-dioxides
    Phosphorus Sulfur and Silicon and the Related Elements, 2005
    Co-Authors: Hooshang Pirelahi, Farnaz Jafarpour, Ghasem Rezanejadebardajee, Javad Amanishamsabaad, Arash Mouradzadegun
    Abstract:

    Syntheses and photoisomerization of the new sulfone derivatives, 4-anisyl-4-methyl-2,6-diphenyl-4H-Thiopyran-1,1-dioxide and 2,6-dianisyl-4-methyl-4-phenyl-4H-Thiopyran-1,1-dioxide, are described. The relative molar ratios of the regioselective photoproducts were compared with those of the unsubstituted model compound under identical experimental conditions using 1H NMR spectroscopy. The results that were observed are discussed on the basis of a vinyl-vinyl thia-di-π -methane rearrangement.

  • Competitive Photochemical Pathways in the Rearrangement of Tetrasubstituted 4H-Thiopyrans
    Monatshefte für Chemie Chemical Monthly, 2004
    Co-Authors: Hooshang Pirelahi, Assieh Atarodiekashani, Seyyedmajid Seyyedmoossavi, Hossein Daryanavardedargahani
    Abstract:

    The photoisomerization of 4,4-dialkyl-2,6-diphenyl-4 H -Thiopyrans and 4-benzyl-2,4,6-triphenyl-4 H -Thiopyran was investigated and compared with those of the 2,4,4,6-tetraaryl- and 4-alkyl-2,4,6-triaryl-4 H -Thiopyran analogues reported earlier. Obviously, the alkyl groups at the 4-positions of the 4 H -Thiopyrans strongly diminish the efficiency of the di-π-methane rearrangement and, contrastingly, a four-electron suprafacial [1,3]-sigmatropic rearrangement is found to be highly efficient.

Samir Zard - One of the best experts on this subject based on the ideXlab platform.

Matthieu Corbet - One of the best experts on this subject based on the ideXlab platform.

Vadim M. Timoshenko - One of the best experts on this subject based on the ideXlab platform.

  • The synthesis and properties of 6-trifluoromethyl-substituted Thiopyrano[3,4-d]isoxazole derivatives
    Chemistry of Heterocyclic Compounds, 2015
    Co-Authors: Serhii A. Siryi, Vadim M. Timoshenko, Yurii G. Vlasenko, Eduard B. Rusanov, Yuriy G. Shermolovich
    Abstract:

    The first representatives of the novel 4,7а-dihydro-3а Н -Thiopyrano[3,4 -d ]isoxazole heterocyclic system, containing an ester, carboxyl, or hydroxymethyl group at position 3 and a trifluoromethyl group at position 6 were obtained by [3+2] cycloaddition reaction of ethyl cyanocarboxylate N -oxide and 6-trifluoromethyl-2 Н -Thiopyran, followed by further transformations of the ethyl 6-trifluoromethyl-4,7а-dihydro-3а Н -Thiopyrano[3,4 -d ]isoxazole-3-carboxylate intermediate. The cleavage of the isoxazoline ring of the obtained compounds led to the formation of 6-trifluoromethyl-2 Н -Thiopyran derivatives with nitrile or carbonyl-containing functionality at position 3. Transformations of the Thiopyran moiety in 4,7а-dihydro-3а Н -Thiopyrano[3,4 -d ]isoxazole were studied for the case of Pummerer reaction product with oxidized sulfur atom, ethyl 6-trifluoromethyl-4,7а-dihydro-3а Н -Thiopyrano[3,4 -d ]isoxazole-3-carboxylate 5-oxide, which was converted to ethyl 6-trifluoromethyl-4 Н -Thiopyrano[3,4 -d ]isoxazole-3-carboxylate.

  • Synthesis of polyfluoroalkyl containing Thiopyran derivatives and their applications in fluoroorganic chemistry
    Journal of Fluorine Chemistry, 2012
    Co-Authors: Sergiy A. Siry, Vadim M. Timoshenko, Jean-philippe Bouillon
    Abstract:

    Abstract An overview of syntheses and chemical properties of polyfluoroalkyl 2 H - and 4 H -Thiopyrans, their hydrogenated (3,4- and 3,6-dihydroThiopyrans, and tetrahydroThiopyrans) and S-oxidized derivatives is presented. The first part is devoted to the synthetic methods starting from acyclic or cyclic precursors, and on multicomponent reactions. The second one deals with the chemical properties of Thiopyran derivatives such as elimination reactions, [4+2] cycloadditions, sulfur or C C double bond oxidations, and reactions with nucleophiles. The last part is focused on the biological evaluation of polyfluoroalkyl 2 H -Thiopyrans, especially as potential cardiotonic agents.

  • Oxidative transformations of 6-trifluoromethyl-2H-Thiopyran as a route to fluoro-containing Thiopyranosides
    Tetrahedron Letters, 2011
    Co-Authors: Sergiy A. Siry, Vadim M. Timoshenko
    Abstract:

    Abstract The synthesis of cis- and trans -6-(trifluoromethyl)-3,4-dihydro-2 H -Thiopyran-3,4-diols from 6-(trifluoromethyl)-2 H -Thiopyran via an OsO 4 -catalysed dihydroxylation and bromohydroxylation–alkaline hydrolysis sequence is described. Acetylation of the diols followed by S -oxidation affords the corresponding cis- and trans -3,4-diacetoxy-6-(trifluoromethyl)-3,4-dihydro-2 H -Thiopyran S-oxides which reacted with acetic anhydride and boron trifluoride diethyl ether complex by an additive Pummerer pathway giving tetraacetyl derivatives of trifluoromethyl-containing Thiopyranoses.

Christopher Barnerkowollik - One of the best experts on this subject based on the ideXlab platform.

  • a study into the stability of 3 6 dihydro 2h Thiopyran rings key linkages in the raft hetero diels alder click concept
    Macromolecules, 2008
    Co-Authors: Sebastian Sinnwell, Christopher V Synatschke, Thomas Junkers, Martina H Stenzel, Christopher Barnerkowollik
    Abstract:

    The combination of RAFT chemistry and hetero-Diels−Alder (HDA) cycloaddition provides a convenient conjugation tool for the construction of macromolecular architectures. The actual conjugation linkage, which is formed in the RAFT HDA approach, consists of a 3,6-dihydro-2H-Thiopyran ring. Herein, a careful study into the stability of polymer linked by 3,6-dihydro-2H-Thiopyran rings under different thermal and pH conditions is performed. As polymeric model system, a 3,6-dihydro-2H-Thiopyran functionalized poly(ethylene glycol) (PEG) obtained after a HDA cycloaddition between a diene functionalized PEG and 1-phenylethyl (diethoxyphosphoryl)dithioformate or 1-phenylethyl pyridin-2-yldithioformate is used. Electrospray ionization mass spectrometry (ESI-MS) is employed to map the generated products. The stability tests under thermal conditions showed for the diethoxyphosphoryl derivative the preservation of the polymer end-groups after 24 h at temperatures up to 80 °C. At higher temperatures degradation reactio...

  • a study into the stability of 3 6 dihydro 2h Thiopyran rings key linkages in the raft hetero diels alder click concept
    Institute for Future Environments; Science & Engineering Faculty, 2008
    Co-Authors: Sebastian Sinnwell, Christopher V Synatschke, Thomas Junkers, Martina H Stenzel, Christopher Barnerkowollik
    Abstract:

    The combination of RAFT chemistry and hetero-Diels-Alder (HDA) cycloaddition provides a convenient conjugation tool for the construction of macromolecular architectures. The actual conjugation linkage, which is formed in the RAFT HDA approach, consists of a 3,6-dihydro-2H-Thiopyran ring. Herein, a careful study into the stability of polymer linked by 3,6-dihydro-2H-Thiopyran rings under different thermal and pH conditions is performed. As polymeric model system, a 3,6-dihydro-2H-Thiopyran functionalized poly(ethylene glycol) (PEG) obtained after a HDA cycloaddition between a diene functionalized PEG and 1-phenylethyl (diethoxyphosphoryl)dithioformate or 1-phenylethyl pyridin-2-yldithioformate is used. Electrospray ionization mass spectrometry (ESI-MS) is employed to map the generated products. The stability tests under thermal conditions showed for the diethoxyphosphoryl derivative the preservation of the polymer end-groups after 24 h at temperatures up to 80°C. At higher temperatures degradation reactions of the 3,6-dihydro-2H-Thiopyran ring including the retro HDA reaction occurred. A complete fragmentation was observed after 24 h at 160°C. The pyridinyl derivative was found to be slightly more temperature stable since its structure was unaffected at conditions up to 24 h at 120°C and full cleavage was only observed after 24 h at 180°C. In this case the fragmentation mechanism occurred exclusively via the retro HDA reaction and the resulting diene functionalized polymer was the only detected product species. Both conjugates showed an excellent stability toward hydrolysis in aqueous media under strong acidic (0.1 and 1 M HCL) and strong basic (0.1 and 1 M NaOH) conditions. © 2008 American Chemical Society.