P‐12.5: Synthesis of Quaterphenyl Liquid Crystalline Isothiocyanates by Successive Alternating Cross‐linking

Due to their high dielectric anisotropy, nematic thioisocyanate quaterphenyl liquid crystals have found application in a wide GHz range. This article proposes a method for obtaining a sequential combination of quaterphenyl derivatives of thioiocyanates containing a methyl group lateral substitute on benzene structure. First, the reaction of pentylphenyl boric acid with diazobromotoluene tetrafluoroborates gives the corresponding biphenyl bromo derivatives, which are converted into organozinc derivatives through the Grignard reagent. Terphenyl bromo derivatives were obtained by the Negishi reaction of organozinc compounds with p‐iodobromobenzene. Terphenyl derivatives after transformation into boric acids were further combined according to the classical scheme.