Patent ID: 6231934
Filing Date: 2001-05-15
Classification: C07C,C09K

Abstract:
A liquid crystalline compound expressed by the general formula (1)Ra-A.sub.1 -Z.sub.1 -A.sub.2 -Z.sub.2 -A.sub.3 -Z.sub.3 -A.sub.4 -Rb (1)wherein Ra represents an alkenyl group having 2 to 20 carbon atoms or an alkyl group having 1 to 20 carbon atoms, any methylene group (--CH.sub.2 --) in the alkenyl or alkyl group may be replaced by --O--, --S--, --CO--, --CH.dbd.CH--, or --C.tbd.C--, but in no case are adjacent methylene groups replaced by --O-- and/or --S--, and any hydrogen atom in Ra may be replaced by a halogen atom; Rb represents Ra, a halogen atom, or cyano group provided that at least one of Ra and Rb represents a group having double bond; A.sub.1, A.sub.2, A.sub.3, and A.sub.4 independently represent trans-1,4-cyclohexylene group, 1,4-phenylene group in which any hydrogen atom on the ring may be replaced by fluorine atom or cyano group, cyclohexenediyl group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, or 1,3-dioxane-2,5-diyl group; Z.sub.1, Z.sub.2, and Z.sub.3 independently represent an alkenylene group having 2 to 4 carbon atoms, --(CH.sub.2).sub.2 --, --COO--, --OCO--, --C.tbd.C--, --CH.sub.2 O--, --OCH.sub.2 --, or single bond, any hydrogen atom in the groups may be replaced by a halogen atom, provided that at least one of Z.sub.1, Z.sub.2, Z.sub.3 represents an alkenylene group having 2 to 4 carbon atoms, none of rings A.sub.1 to A.sub.4 adjacent to the alkenylene group is 1,4-phenylene group, and when all of rings A.sub.1, A.sub.2, and A.sub.3, or all of rings A.sub.2, A.sub.3, and A.sub.4 are trans-1,4-cyclohexylene group, then Z.sub.2 is not an alkenylene group.