摘要 |
Compounds of the formula <IMAGE> I wherein n stands for the number 0 or 1; rings A, B and C each independently represent trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl or unsubstituted or fluoro-substituted 1,4-phenylene; R1 denotes 3E-alkenyl with 4 to 12 carbon atoms, 4-alkenyl with 5 to 12 carbon atoms or, when ring A represents trans-1,4-cyclohexylene or trans-1,3-dioxane-2,5-diyl, also 1E-alkenyl with 2 to 12 carbon atoms; and R2 is hydrogen or C1-C10-alkyl, their manufacture as well as liquid crystalline mixtures which contain such compounds and their use for electro-optical purposes.
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