| 摘要 |
Cyclic compounds have the formula I R<1>-(A<1>-Z<1>)n-A<2>-R<2>, in which R<1> is alkyl with 1 to 12 C atoms, wherein one or several non-adjacent CH2 groups may be substituted with -O-, -CO-, -O-CO- and/or -CO-O-, A<1> and A<2> are independently from each other trans-1,4-cyclohexylene, wherein one or two non-adjacent CH2 groups may be substituted with O and/or S, or 1,4-phenylene unsubstituted or substituted with halogen, CN and/or CH3, wherein one or several CH groups may be substituted with N, Z<1> is -CO-O-, -O-CO-, -CH2CH2- or a simple compound, n is 1,2 or 3, and R<2> is -CO-CH2-COO-alkyl, -O-CO-O-alkyl or in case A<2> = trans-1,4-cyclohexylene, it can also be -CO-CH2-CO-alkyl. Alkyl represents a straight chain or a simple ramified alkyl group with 1 to 10 C atoms, provided that if R<2> = -O-CO-O-alkyl, R<1>-(A<1>-Z<1>)n-A<2>- represents (a), (b) or (c). These compounds are useful as components of liquid crystal phases.
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