- Improved synthesis of trans-4-alkylcyclohexane carboxylic acids
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Several stereomerically pure amino acid derivatives containing the N-terminal trans-4-alkylcyclohexanoyl fragment were obtained. Hydrogenation of 4-alkylbenzoic acids in the presence of a special Ru-Ni/C catalytic system and isomerization of the resulting mixture of trans- and cis-isomers of 4-alkylcyclohexanecarboxylic acids were used as the key steps. The stereomeric configuration of all compounds was confirmed by 1H NMR spectroscopy. The compounds obtained possess a broad biological activity potential and are useful intermediates in the synthesis of stereomerically pure modified peptides.
- Bazurin, Alexey A.,Krasnikov, Sergey V.,Obuchova, Tatiana A.,Danilova, Angelina S.,Balakin, Konstantin V.
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p. 6669 - 6672
(2007/10/03)
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- Synthesis and Physical Properties of Alkoxymethylene Substituted Phenyl Cyclohexanecarboxylates
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The homologous series of 4-alkoxymethylene-substituted-phenyl 4'-alkylcyclohexanecarboxylates are prepared.And their transition temperatures, bulk viscosities and birefringences have been measured comparing with the series of 4-alkoxy-substituted-phenyl 4'-alkylcyclohexanecarboxylates.The differences between the alkoxymethylene-substituted series and alkoxy-substituted series are discussed.Alkoxymethylene groups contribute to lowering the transition temperatures, and also reducing the bulk viscosities and optical anisotropy compared to the alkoxy groups as terminal groups of mesogens.This is apparently due to the higher flexibility of the alkoxymethylene groups, which affected the packing of molecules.
- Kitamura, Teruo,Mukoh, Akio,Era, Susumu,Fujii, Tsunenori
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p. 231 - 248
(2007/10/02)
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- 1-(TRANS-4 prime -N-ALKYLCYCLOHEXYL)-2-(4 double prime -CYANOPHENYL)ETHANES - A NEW SERIES OF STABLE NEMATOGENS OF POSITIVE DIELECTRIC ANISOTROPY.
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The synthesis and some important properties of the 1-(trans-4 prime -n-alkylcyclohexyl)-2-(4 double prime -cyanophenyl)ethanes - where n-alkyl equals C//1 to C//7 - are described.
- Carr,Gray,McDonnell
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- The Synthesis and Liquid Crystal Properties of Some Laterally Fluorinated trans-Cyclohexane-1-carboxylate and Benzoate Esters
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A large number of laterally fluorinated 4-n-alkyl- and -alkoxy-phenyl 4'-n-alkyl- and -alkoxy-bezoates and 4-n-alkylphenyl trans-4'-n-alkyl- and -alkoxy-cyclohexane-1-carboxylates were synthesised.In these compounds, the lateral fluoro-substituent was situated in either the phenol or the carboxylic acid moiety of the molecules for the benzoate esters, but only in the phenol moiety for the trans-cyclohexane-1-carboxylate esters.The nematic thermal stabilities for the fluorophenyl bezoate and trans-cyclohexane-1-carboxylate esters and the fluorobenzoate esters were compared with those for the corresponding non-fluorinated analogues.A nematic thermal efficiency order was derived for the 4-n-alkyl-fluorophenyl 4-n-alkylbezoate and trans-4-n-alkylcyclohexane-1-carboxylate esters, but only in the case of the latter esters, which were extensively examined, was the smectic tendency of the system investigated.Explanations are given for the observed nematic and smectic thermal stabilities of the titled esters, and some of their physical properties are discussed.
- Gray, G. W.,Hogg, C.,Lacey, D.
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