OPTICALLY ACTIVE DIOXOLANYLACRYLIC AND DIOXOLANYLPROPIONIC ACID ESTERS CONTAINING A MESOGENIC RESIDUE, A PROCESS FOR MANUFACTURING THEM AND THEIR USE AS DOPING AGENTS IN LIQUID CRYSTAL MIXTURES

摘要

HOE 89/F 080 of the disclosure Optically active dioxolanylacrylates and dioxolanylpropionates carrying a mesogenic radical, a process for their preparation, and their use as dopes in liquidcrystal mixtures. Optically active 1,3-dioxolane derivatives, carrying a mesogenic radical, of the general formula (I) (I) are suitable as dopes in - in particular ferroelectric liquid-crystal mixtures. The symbols in the general formula have the following meaning here: R1 is constructed analogously to the moiety of the general formula on the right of X or is an alkyl or alkylene ¢sic! radical which may be substituted, R2, R3 and R4 are H or alkyl (R4 is alternatively alkenyl), which may also be substituted ¢R2 and R3, together with the C(2) of the dioxolane ring, are a cycloaliphatic radical or a keto group!, j, l and n are zero, 1 or 2, and k and m are zero or 1, with the proviso that n = zero if k = zero, m = zero if n = zero, and 1 ? j + 1 + n ? 3, -A1, -A2 and -A3 are an aromatic, heterocyclic or aliphatic ring system, -M1 and -M2 are -CO-O, -O-CO, -CH2CH2, -CH=CH, -CH2O, -OCH2 or -C=C, and X is CH=CH or CH2-CH2. The particular advantage of the compounds of the general formula (I) is that they are able to induce a high twisting power in a cholesteric phase, but without significantly affecting, in the smectic C* phase, the magnitude of the spontaneous polarization already present in a mixture. They are therefore suitable for pitch compensation, in particular for ferroelectric liquidcrystal mixtures.