NEW OPTICALLY ACTIVE ESTERS OF 5-ETHYL AND 5-VINYL-1,3-DIOXOLAN-4-CARBONIC ACIDS, THEIR USE AS DOPING SUBSTANCES IN LIQUID CRYSTAL MIXTURES AND THE NEW ESTER CONTAINING LIQUID CRYSTAL MIXTURES

摘要

Novel optically active esters of 5-ethyl- and 5-vinyl-1,3- dioxolane-4-carboxylic acid, their use as dopes in liquid-crystal mixtures, and liquid-crystal mixtures containing the novel esters. Optically active 1,3-dioxolanyl derivatives of the general formula (I) IMAGE are suitable as dopes in liquid-crystal mixtures. The symbols in the general formula have the following meanings: R1 has an analogous structure to the moiety on the right of X in the general formula or is an alkyl or alkylene radical, which may be substituted, R2 and R3 are H or alkyl, which may also be substituted [R2 and R3 are alternatively, together with the C(2) of the dioxolane ring, a cycloaliphatic radical] R4 is vinyl or ethyl, with the proviso that at least one radical R4 is vinyl or ethyl if R1 is analogous to the moiety on the right of X in the formula (I), -A1, -A2 and -A3 are aromatic, heterocyclic or aliphatic ring systems, -M1 and -M2 are -CO-O, -O-CO, -CH2CH2, -CH=CH, -CH2O,-OCH2 or -C=C, and X is O, S or O-CO-O. The particular advantage of the compound of the general formula (I) is that it is able to induce high twisting power in a cholesteric phase.