Synthesis and mesomorphic properties of new liquid crystalline compounds with ß-hydroxy-, ß-chloroketone and a,ß-unsaturated ketone moieties in the terminal chains

Abstract

The syntheses of new liquid crystalline compounds containing β-hydroxy-, β-chloroketone and α,β-unsaturated ketone moieties are described. The key intermediate 1-(4-hydroxyphenyl)-3-hydroxyoctan-1-one was obtained by the hydrogenolysis of the heterocycle in 3-(4-hydroxyphenyl)-5-pentyl-2-isoxazoline. Dehydratation of the intermediate β-hydroxyketone led to 1-(4-hydroxyphenyl)-oct-2-en-1-one. Reaction of 1-(4-hydroxyphenyl)-3-hydroxyoctan-1-one with hydrochloric acid yielded 1-(4-hydroxyphenyl)-3-chlorooctan-1-one. The target liquid crystalline compounds were synthesized by the esterification of these phenols with corresponding acids. The relationships between the moiety type in the terminal chain and the liquid crystalline properties are discussed.