Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.303, 313-318, 1997
New Synthesis of the Liquid-Crystalline Bicyclohexylbenzene Derivatives
A new improved approach to prepare the liquid crystalline bicyclohexylbenzene derivatives is proposed. The key stage is the synthesis of 3-(trans-4-arylcyclohexyl)-6-alkyl (or aryl) cyclohex-2-en-1-ones via the condensation of the corresponding Mannich salts with 2-substituted acetoacetic esters (or methyl benzyl ketones) in the presence of a base. The catalytic hydrogenation of these cyclohexenones in base media gives mainly saturated trans-ketones which are promising semiproducts for the preparation of different kinds of the LC compounds containing a bicyclohexyl fragment. The chemical transformations of the prepared cyclohexanones were carried out and as a result a range of LC compounds both known and new ones were synthesized.
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