D-xylose derivative liquid crystals

We studied the phase transition temperatures of a series of amphiphilic D-x ylopyranose and D-xylofuranose derivatives in which the lipophilic part is an alkyl chain R(n-CnH2n+1), regiospecifically linked to D-xylose, at diffe rent positions, by Z which is an atom or a functional group (O, S, O-(CH2)( 3)-S). The alkyl chain was moved from the C-1 to the C-5 position in the xy lose moiety, thereby allowing us to compare directly the phase transition t emperatures of the individual materials. These compounds give thermotropic and/or lyotropic liquid crystals. In some cases, we also observed solid-sol id phase transitions.