PB08 Synthesis and Properties of Substituted Pyrano [3, 2-c] [1] benzopyrans for New Liquid Crystal Compounds

Abstract

We studied the application of pyrano [3, 2-c] [1] benzopyran system as a core structure of new liquid crystal compounds. Pyranobenzopyrans can be prepared in one-pot reaction by the intramolecular [4+2] cycloaddition of orthoquinonemethides, which are in turn generated from salicylaldehydes and 4-alken-l-ols. Some compounds obtained were evaluated by T_c, Δn, kinetic viscosity (η), and viscosity coefficient (η_r) upon addition to the base LC mixture by 10wt%. Introduction of fluorophenyl groups on the A ring shows liquid crystalline phase and rises T_c without changing Δ n of the LC mixture.