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'Conformation' in keywords Facet   Publication Year 1990  [X]
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1990[X]
1Author    V. Vill, J. ThiemRequires cookie*
 Title    Flüssigkristalle mit monosubstituierten alicyclischen und heteroalicyclischen Ringen Liquid Crystals Derived from Mono-Substituted Alicyclic and Heteroalicyclic Rings  
 Abstract    Twenty two liquid crystalline mono-substituted cyclopentanes and cyclohexanes including their oxygen analogues were prepard and studied. Smectic phases with clearing temperatures 5^80 °C were observed, and these do not differ considerably between the esters of the more flexible five-mem-bered ring derivatives and those of the conformationally more rigid six-membered rings. In case of the latter, decreasing clearing points ar observed with increasing ratios of the axial conformation (static conformational effect). Altogether rather low clearing points are observed, which may be interpreted by a dynamic conformational effect owing to which fast ring inversion causes the compounds to appear in a bulkier shape, and this results in a disadvantageous packing in the mesophase. 
  Reference    Z. Naturforsch. 45a, 1345—1348 (1990); eingegangen am 21. Oktober 1990 
  Published    1990 
  Keywords    Alicyclic rings, Liquid crystals, Conformation, Oxygen heterocycles 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-1345.pdf 
 Identifier    ZNA-1990-45a-1345 
 Volume    45 
2Author    Ryszard Stolarskia, JaroslawM. Cieslab, David ShugarabRequires cookie*
 Title    Monophosphates and Cyclic Phosphates of Some Antiviral Acyclonucleosides: Synthesis, Conformation and Substrate/Inhibitor Properties in Some Enzyme Systems  
 Abstract    Chemical and enzymatic procedures are described for the synthesis o f the m onophosphates and cyclic phosphates o f the antiviral acyclonucleoside 9-(1,3-dihydroxy-2-propoxym ethyl)-guanine (D H PG), its 3-hydroxymethyl-4-hydroxybutyl analogue, the (/?)-and (S)-epimers o f 9-(3,4-dihydroxybutyl)guanine, and 9-(2,3-dihydroxypropyl)guanine. The structures, and some conform ational features, o f all the foregoing, were determined by 'H and 3IP N M R spectroscopy. Their substrate/inhibitor properties have been examined in several enzyme systems, including ribonucleases, snake venom phosphodiesterase, beef heart and higher plant cyclic nucleotide phosphodiesterases, nuclease P I, and 3'-and 5'-nucleo-tidases. The enzymatic results are considered in relation to the mechanism o f the antiviral ac­ tivity o f the cyclic phosphate o f D H PG . 
  Reference    Z. Naturforsch. 45c, 293 (1990); received October 31 1989 
  Published    1990 
  Keywords    Acyclonucleosides, M onophosphates, Cyclic Phosphates, Conformation, Substrate/Inhibitor Properties 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0293.pdf 
 Identifier    ZNC-1990-45c-0293 
 Volume    45