Azine derivative, process for the preparation thereof, nematic liquid crystal composition and liquid crystal display system comprising same

A process for the preparation of a compound represented by the general formula (I):

• ##STR155## wherein m and n each independently represent an integer of 0 or 1;
• rings A, B, C and D each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• R represents a C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• and Z represents a fluorine atom, chlorine atom, bromine atom, cyano group, --OCF.sub.3, --OCF.sub.2 H, --CF.sub.3, --OCH.sub.2 CF.sub.3, C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group, which comprises allowing a compound represented by the following general formula (II):
• ##STR156## wherein Z represents a fluorine atom, chlorine atom, bromine atom, cyano group, --OCF.sub.3, --OCF.sub.2 H, --CF.sub.3, --OCH.sub.2 CF.sub.3, C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• rings C and D each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• and m represents an integer of 0 or 1
• and a compound represented by the following general formula (III):
• ##STR157## wherein R represents a C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• rings A and B each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• and n represents an integer of 0 or 1
• to undergo reaction in the presence of an amine.

A process for the preparation of a compound represented by the general formula (I):

• ##STR158## wherein m and n each independently represent an integer of 0 or 1;
• rings A, B, C and D each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• R represents a C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• and Z represents a fluorine atom, chlorine atom, bromine atom, cyano group, --OCF.sub.3, --OCF.sub.2 H, --CF.sub.3, --OCH.sub.2 CF.sub.3, C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group,
• which comprises allowing a compound represented by the following general formula (IV):
• ##STR159## wherein Z represents a fluorine atom, chlorine atom, bromine atom, cyano group, --OCF.sub.3, --OCF.sub.2 H, --CF.sub.3, --OCH.sub.2 CF.sub.3, C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• rings C and D each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• and m represents an integer of 0 or 1
• and a compound represented by the following general formula (V):
• ##STR160## wherein R represents a C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• rings A and B each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• and n represents an integer of 0 or 1
• to undergo reaction in the presence of an amine.

A nematic liquid crystal composition, comprising a compound represented by the general formula (I):

• ##STR161## wherein m and n each independently represent an integer of 0 or 1;
• rings A, B, C and D each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• R represents a C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• and
• Z represents a fluorine atom, chlorine atom, bromine atom, cyano group, --OCF.sub.3, --OCF.sub.2 H, --CF.sub.3, --OCH.sub.2 CF.sub.3, C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group,
• with the proviso that Z is not an alkyl group, cyano group, fluorine atom, chlorine atom or bromine atom when m and n each are 0 and rings B and C each are 1,4-phenylene group and R is an alkyl group.

A nematic liquid crystal composition, comprising as a liquid crystal component A a compound represented by the general formula (I):

• ##STR162## wherein m and n each independently represent an integer of 0 or 1;
• rings A, B, C and D each independently represent 1,4-phenylene group which may be substituted by fluorine atom, trans-1,4-cyclohexylene group, pyrimidine-2,5-diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group, pyridazine-3,6-diyl group or trans-1,3-dioxane-2,5-diyl group;
• R represents a C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group;
• and
• z represents a fluorine atom, chlorine atom, bromine atom, cyano group, --OCF.sub.3, --OCF.sub.2 H, --CF.sub.3, --OCH.sub.2 CF.sub.3, C.sub.1-12 alkyl group or alkoxyl group, C.sub.2-12 alkenyl group or alkoxylalkyl group or C.sub.3-12 alkenyloxy group
• and as a liquid crystal component B a compound having a dielectric anisotropy of not less than +2,
• wherein as said liquid crystal component B there is incorporated a compound selected from the group consisting of compounds represented by the following general formulae (II-1) to (II-4):
• ##STR163## wherein R.sup.21 to R.sup.24 each independently represent a C.sub.2-10 straight-chain alkyl group, alkenyl group or C.sub.s H.sub.2s+1 --O--C.sub.t H.sub.2t in which s and t each independently represent an integer of from 1 to 5;
• X.sup.21 to X.sup.24 each independently represent a fluorine atom, chlorine atom, --OCF.sub.3, --OCHF.sub.2, --CF.sub.3 or --CN;
• Y.sup.21 to Y.sup.29 each independently represent a hydrogen atom or fluorine atom;
• W.sup.21 to W.sup.24 each independently represent a hydrogen atom or fluorine atom;
• Z.sup.21 to Z.sup.23 each independently represent a single bond, --COO--, --CH.sub.2 CH.sub.2 -- or --(CH.sub.2).sub.4 --;
• Z.sup.21 may also represent --C.dbd.C-- or --CH.dbd.CH--;
• Z.sup.24 and Z.sup.25 each independently represent a single bond, --COO--, --C.dbd.C-- or --CF.dbd.CF--;
• and
• m.sup.1 to m.sup.4 each independently represent an integer of from 0 or 1, with the proviso that m.sup.3 +m.sup.4 make an integer of 0 or and hydrogen atoms in the cyclohexane ring in the compounds (II-1) to (II-4)may be replaced by deuterium atoms (D).