Diphenylacetylene compound, process for preparing the same and liquid crystal composition and element comprising the same

A liquid crystal composition comprising a diphenylacetylene compound of the formula [1]:

• ##STR36## wherein R is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2-C.sub.16 alkoxyalkyl group;
• X.sup.1, X.sup.2, X.sup.3, X.sup.4, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are independently from each other a --CH-- group, a --CF-- group or a nitrogen atom;
• A is a hydrogen atom, a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkyl) group, 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkenyl) group or a R.sup.1 --(O).sub.m group in which R.sup.1 is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.12 alkynyl group;
• and m is0 or 1.

A process for preparing a diphenylacetylene compound of the formula (1):

• ##STR37## wherein R is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.16 alkoxyalkyl group;
• X.sup.1, X.sup.2, X.sup.3, X.sup.4, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are independently from each other a --CH-- group, a --CF-- group or a nitrogen atom;
• A is a hydrogen atom, a fluorine atom, a trifluoromethyl group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkyl) group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkenyl) group or a R.sup.1 --(O).sub.m group in which R.sup.1 is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.12 alkynyl group;
• and m is 0 or 1;
• comprising reacting an aromatic compound of the formula (2):
• ##STR38## wherein A, X.sup.1, X.sup.2, X.sup.3, X.sup.4, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are the same as defined above, and D is a halogen atom or --OSO.sub.2 R' in which R' is a C.sub.1 -C.sub.5 alkyl group which may be substituted by a fluorine atom or an alkyl-, alkoxy-, or halogen-substituted or unsubstituted phenyl group;
• with an ethynyl aromatic derivative of the formula (3);
• ##STR39## wherein R, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are the same as defined above and wherein said ethynyl aromatic derivative is prepared by treating a carbinol derivative of the formula (7):
• ##STR40## wherein R, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are the same as defined above, with a base;
• wherein said carbinol derivative of the formula (7) is prepared by reacting a carbinol derivative of the formula (5):
• ##STR41## wherein D, Y.sup.1, Y.sup.2, Y.sup.3, and Y.sup.4 are the same as defined above, with a boron compound of the formula (6):
• ##STR42## wherein R and each R.sup.5 is a hydroxyl group, a C.sub.1 -C.sub.8 straight alkyl group, a C.sub.2 -C.sub.8 branched alkyl group, a C.sub.3 -C.sub.8 cycloalkyl group, a C.sub.1 -C.sub.8 straight alkyoxy group, a C.sub.2 -C.sub.8 branched alkoxy group, a C.sub.3 -C.sub.8 cycloalkoxy group, or the two R.sup.5 groups together form a C.sub.1 -C.sub.8 straight alkylene group, a C.sub.2 -C.sub.8 branched alkylene group, a C.sub.3 -C.sub.8 cycloalkylene group, a C.sub.1 -C.sub.8 straight alkylenedioxy group, a C.sub.2 -C.sub.8 branched alkylenedioxy group, a C.sub.3 -C.sub.8 cyclic alkylenedioxy group or a benzodioxy group, in the presence of a metal catalyst and a base;
• in the presence of a metal catalyst and a base.

A process for preparing a diphenylacetylene compound of the formula (1):

• ##STR43## wherein R is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.16 alkoxyalkyl group;
• X.sup.1, X.sup.2, X.sup.3, X.sup.4, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are independently from each other a --CH-- group, a --CF-- group or a nitrogen atom;
• A is a hydrogen atom, a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkyl) group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkenyl) group or a R.sup.1 --(O).sub.m group in which R.sup.1 is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.12 alkynyl group;
• and m is 0 or 1:
• comprising reacting a diphenylacetylene derivative of the formula (10):
• ##STR44## wherein A, X.sup.1, X.sup.2, X.sup.3, X.sup.4, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are the same as defined above, and D is a halogen atom or --OSO.sub.2 R' in which R' is a C.sub.1 -C.sub.5 alkyl group which may be substituted by a fluorine atom or an alkyl-, alkoxy-, or halogen-substituted or unsubstituted phenyl group with a boron compound of the formula (6):
• (R.sup.5).sub.2 B--CH.dbd.CH--R (6)
• (trans)
• wherein R is the same as defined above and each R.sup.5 is a hydroxyl group, a C.sub.1 -C.sub.8 straight alkyl group, a C.sub.2 -C.sub.8 branched alkyl group , a C.sub.3 -C.sub.8 cycloalkyl group, a C.sub.1 -C.sub.8 straight alkyoxy group, a C.sub.2 -C.sub.8 branched alkoxy group, a C.sub.3 -C.sub.8 cycloalkoxy group, or the two R.sup.5 groups together form a C.sub.1 -C.sub.8 straight alkylene group, a C.sub.2 -C.sub.8 branched alkylene group, a C.sub.3 -C.sub.8 cycloalkylene group, a C.sub.1 -C.sub.8 straight alkylenedioxy group, a C.sub.2 -C.sub.8 branched alkylenedioxy group , a C.sub.3 -C.sub.8 cyclic alkylenedioxy group or a benzodioxy group;
• in the presence of a metal catalyst and a base.

A process for preparing a diphenylacetylene compound of the formula (1):

• ##STR45## wherein R is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.16 alkoxyalkyl group;
• X.sup.1, X.sup.2, X.sup.3, X.sup.4, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are independently from each other a --CH-- group, a --CF-- group or a nitrogen atom;
• A is a hydrogen atom, a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkyl) group, a 4-R.sup.1 -(C.sub.3 -C.sub.8 cycloalkenyl) group or a R.sup.1 --(O).sub.m group in which R.sup.1 is a C.sub.1 -C.sub.12 alkyl group, a C.sub.2 -C.sub.12 alkenyl group or a C.sub.2 -C.sub.12 alkynyl group;
• and m is 0 or 1;
• comprising reacting an ethynyl aromatic compound of the formula (11):
• ##STR46## wherein A, X.sup.1, X.sup.2, X.sup.3, and X.sup.4, are the same as defined above;
• wherein said ethynyl aromatic compound (11) is synthesized by a process:
• ##STR47## with an aromatic derivative of the formula (12):
• ##STR48## wherein R, Y.sup.1, Y.sup.2, Y.sup.3 and Y.sup.4 are the same as defined above, and D is a halogen atom or --OSO.sub.2 R' in which R' is a C.sub.1 -C.sub.5 alkyl group which may be substituted by a fluorine atom or an alkyl-, alkoxy-, or halogen-substituted or unsubstituted phenyl group;
• wherein said aromatic derivative of the formula (12) is synthesized by a process:
• ##STR49## (1) when D is a halogen atom:
• ##STR50## (2) when D is --OSO.sub.2 R:
• ##STR51## in the presence of a metal catalyst and a base.