ChemInform Abstract: Mesogenic N-(4-(4-Alkoxyphenyldiazo)benzylidene)-4-cyanoanilines.

ChemInform Abstract

An optimized method for the synthesis of title compounds of type (VII) is described. The lower homologues (n ≤ 5) are best prepared in refluxing ethanol, whereas the higher ones (n ≥ 6) are formed in high yields by condensation of the corresponding aldehydes (V) with p-cyanoaniline (VI) in a melt, without a solvent. (VII) form liquid-crystal phases, which are highly stable over a wide range of temperature. As a peculiarity it may be noted that the compound (VIIb) displays a monotropic smectic A phase and an enantiotropic nematic N phase.