New (1R,4R)-2-arylidene-p-menthan-3-ones with a bridging ester group in the arylidene fragment. Synthesis and behavior in liquid-crystalline systems

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• 作者：V.V. Vashchenko ; L.A. Kutulya ; M.N. Pivnenko and N.I. Shkolnikova
• 关键词：(1R ; 4R) ; 2 ; (4 ; hydroxybenzylidene) ; and (1R ; 4R) ; 2 ; (4"" ; hydroxybiphenyl ; 4 ; yl)methylene ; p ; menthan ; 3 ; ones ; chiral esters ; synthesis ; mesomorphic properties ; smectic A mesophase ; twist grain boundary mesophase (TGBA) ; blue phases ; helical twisting power
• 刊名：Russian Chemical Bulletin
• 出版年：2003
• 出版时间：November 2003
• 年：2003
• 卷：52
• 期：11
• 页码：2406-2418
• 全文大小：6 KB

文摘

(1R,4R)-2-(4-Hydroxybenzylidene)- and (1R,4R)-2-(4""-hydroxybiphenyl-4-yl)methylene-p-menthan-3-ones were synthesized by condensation of (–)-menthone with O-tetrahydropyran-2-yl derivatives of 4-hydroxybenzaldehyde and 4""-hydroxy-4-formylbiphenyl, respectively, in a DMSO—base medium followed by the removal of the protective group. The reactions of these hydroxy derivatives with 4-alkylbenzoic, 4-alkyloxybenzoic, trans-4-alkylcyclohexane-4-carboxylic, and 4""-alkylbiphenyl-4-carboxylic acids afforded three series of new chiral esters. Compounds containing the arylidene moiety with three benzene rings were found to exhibit liquid-crystalline properties. The characteristic features of these compounds are discussed based on the results of studies by polarizing microscopy, differential scanning calorimetry, and small-angle X-ray scattering. It was found that the mesomorphic compounds under study can form a smectic A mesophase, twist grain boundary mesophases (TGBA), and blue phases in a wide temperature range. Upon dissolution of certain of chiral compounds in 4""-cyano-4-pentylbiphenyl, a rather high twisting power and the thermal stabilizing effect on mesophases were observed.