New Heterocyclic Liquid Crystalline Compounds

Mesomorphic derivatives of 2-substituted 5-p-alkyl(alkoxy or cyano)phenylpyridines, 1,4-disubstituted piperidines, and ethyl 5-p-alkylphenylthiophene-2-carboxylates have been synthesised and their liquid crystal properties compared with those of analogous benzene and cyclohexane derivatives. Intermediates in the pyridine derivative synthesis 2-thienyl- and 2-furylpyridines-have been found to be mesomorphic too. Some piperidine compounds containing the cyano group in the benzene ring exhibit a large (over + 30) positive dielectric anisotropy.