Antiferroelectric liquid crystal compound

An antiferroelectric liquid crystal compound of the following formulae: ##STR1## wherein R.sup.1 and R.sup.2 each is an alkyl group of C.sub.4 - C.sub.18, Rf is CF.sub.3 or C.sub.2 F.sub.5, X is O, COO, or a single bond, and * shows an optically active carbon atom.

FIELD OF THE INVENTION 
The present invention relates to a novel antiferroelectric liquid crystal 
compound having a terphenyl structure. 
BACKGROUND OF THE INVENTION 
Liquid crystals have excellent characteristics from various points of view, 
namely, 
1) they can be operated at a low voltage; 
2) they consume only small amount of power; 
3) panel type displays can be used; and 
4) they are passive type matrixes. 
Accordingly, electrooptical apparatuses using nematic liquid crystals such 
as a DSM cell, TN cell, G-H cell, or STN cell have been developed and 
practically used. However, all of the electrooptical apparatuses using 
such nematic liquid crystals have a defect that response time is as slow 
as several milli sec to several tens milli sec, leading to a restriction 
in their applications. 
In order to solve these problems, active matrix drive systems using STN 
cells or thin-film transisters were developed. However, STN type displays 
have problems that a high accuracy is required in controls of cell gap and 
tilt angle and that response time is rather slow, while they are excellent 
in such qualities as display contrast and viewing angle. 
With such a technical background, the development of a ferroelectric liquid 
crystal had been attempted which has a spontaneous polarization (Ps), has 
a strong torque based on Ps.times.E (E is an applied voltage), and has an 
extremely short optical response time of a few .mu.sec to several tens of 
.mu.sec to make the preparation of a hypervelocity device possible. 
Meyer et al. synthesized DOBAMBC 
(p-decyloxy-benzilidene-p-ammino-2-methylbutyl cinnamate) in 1975 for the 
first time in the world and which was confirmed to be a ferroelectric 
liquid crystal (Le Journal de Physique, Vol. 36, 1975, L-69). 
Further, since Clark and Lagawall reported in 1980 on such characteristics 
on display devices as high velocity response of submicroseconds and memory 
characteristics of DOBAMBC, ferroelectric liquid crystals have absorbed 
considerable public attention (N. A. Clark et al., Appl. Phys. Lett. 36, 
899 (1980)). 
However, from a practical standpoint, there were many technical problems in 
that system. In particular, no material exhibited ferroelectric liquid 
crystallinity at an ambient temperature, and an effective and practical 
method was not established to control the molecular alignment of the 
liquid crystal molecules. Controlling the molecular alignment of liquid 
crystal molecules is essential for applications in liquid crystal devices. 
After the publication of the report, various attempts have been made from 
both aspects of liquid crystal materials and device. Display devices 
utilizing the switching between twisted bistable states were prepared for 
trial, and high speed electrooptical apparatuses using the device are 
proposed in U.S. Pat. No. 4,367,924 and others. However, high contrast and 
proper potential of threshold value have not been obtained. 
From such a point of view, other switching systems were explored to propose 
a transitional diffusion system. subsequently, a three states switching 
system of liquid crystal having tristable states was reported in 1988 
(A.D. L. Chandani, T. Hagiwara, Y. Suzuki et al., Japanese J. of Appl. 
Phys., 27, (5), L729-L732 (1988)). 
The optically tristable states herein referred to mean that, when voltage 
in the form of a triangular wave as shown in FIG. 1A is applied to liquid 
crystal electrooptical devices where antiferroelectric liquid crystals are 
laid between the first electrode substrate plate and the second electrode 
substrate plate which is apart at a given space from the first one, the 
antiferroelectric liquid crystals show the first stable molecular 
orientation and resulting the first optically stable state as shown in 
FIG. 3 (a), and FIG. 1(D) at reference point 2, respectively, when 
electric voltage is zero. The antiferroelectric liquid crystals show the 
second stable molecular orientation and resulting the second optically 
stable state as shown in FIG. 3 (b), and FIG. 1(D) at reference point 1, 
respectively, in one of the direction of electric field; and show the 
third stable molecular orientation and resulting the third optically 
stable state as shown in FIG. 3 (c), and FIG. 1(D) at reference point 3, 
respectively, in the other direction of electric field. 
Liquid crystal electrooptical apparatuses utilizing the tristable states, 
that is three stable states, are proposed in U.S. Pat. No. 5,046,823 filed 
by the present applicant. 
The characteristics of an antiferroelectric liquid crystal showing the 
tristable states are described in more detail below. 
In the ferroelectric liquid crystal element having a stabilized surface 
which was proposed by Clark-Lagawall, ferroelectric liquid crystal 
molecules show two stable states in which the molecules are uniformly 
oriented or aligned in one direction in the phase S*C. The molecules are 
stabilized in either state depending on the direction of applied electric 
field as shown in FIG. 2 at (a) and (b), and the state is kept even when 
the electric field was shut off. 
Actually, however, the alignment of the ferroelectric liquid crystal 
molecules shows twisted two states in which directors of the liquid 
crystal molecules are twisted or shows a chevron structure in which layers 
are bent in a doglegged shape. In the chevron layer structure, switching 
angle becomes small, forming a cause for a low contrast, and which 
constitute a serious obstacle for its practical use. 
On the other hand, in the liquid crystal electrooptical devices, an "anti" 
ferroelectric liquid crystal molecules are aligned in antiparallel, 
tilting in opposite direction at every adjoining layer, in the phase 
S*.sub.(3) showing the tristable states, and thus, the dipoles of the 
liquid crystal molecules are negating each other. Accordingly, the 
spontaneous polarization is nullified as a whole. The transmittance of the 
liquid crystal phase showing such molecular alignment corresponds to 
reference point 2 in FIG. 1(D). 
Further, when a voltage sufficiently higher than a threshold value of (+) 
or (-) was applied, liquid crystal molecules shown in FIG. 3 at (b) or (c) 
are tilted in the same direction and aligned in parallel. In this state, 
the spontaneous polarization is produced since the dipoles are also 
shifted to the same direction to form a ferroelectric phase, and the 
transmittance of the liquid crystal phase in that state corresponds to 
reference points 1 and 3 in FIG. 1(D). 
That is, in the phase S*.sub.(3) of the "anti" ferroelectric phase, the 
"anti" ferroelectric phase at the time of no-electric field and two 
ferroelectric phases due to the polarity of applied electric field are 
stabilized, and switching is carried out among tristable states of an 
"anti" ferroelectric phase and two ferroelectric phases, with a direct 
current-like threshold value. Based on the change in the alignment of 
liquid crystal molecules accompanied with the switching, light 
transmittance is changed while drawing such a double hysteresis as shown 
in FIG. 4. 
One of the characteristics of the present invention is that a memory effect 
can be realized by applying a bias voltage to the double hysteresis as 
shown in FIG. 4 at reference point (A) and further applying a pulse 
voltage. 
Moreover, the ferroelectric phase is stretched in terms of its layer by the 
application of an electric field to form a book-shelf structure. On the 
other hand, in the "anti" ferroelectric phase at the time of no electric 
field, an analogous book-shelf structure is formed. Since the layer 
structure switching due to the application of an electric field gives a 
dynamic shear to liquid crystal layers, an alignment defect is improved 
during driving, and thus, a good molecular alignment can be realized. 
In the "anti" ferroelectric liquid crystal, since image display is 
performed by alternatively using both hysteresises of plus side and minus 
side, after-image phenomenon due to the accumulation of inner electric 
field based on the spontaneous polarization can be prevented. 
As explained above, the "anti" ferroelectric liquid crystal can be said to 
be a very useful liquid crystal compound having advantages as follows: 
1) Hipervelocity response is possible, 
2) High contrast and wide viewing angle can be expected, and 
3) Excellent alignment characteristics and memory effect can be realized. 
Reports are made on the liquid crystal phase of the "anti" ferroelectric 
liquid crystal showing the tristable states in the following articles: 
1 ) A. D. L. Chandani et al., Japanese J. Appl. Phys., 28, L-1265 (1989), 
and 
2) H. Orihara et al., Japanese J. Appl. Phys., 29, L-333 (1990 ). 
The liquid phase is called "Phase S*.sub.CA " (Antiferroelectric Smectic C 
phase) in association with the "anti" ferroelectric property. The phase is 
named "phase S*.sub.(3) " in the present specification since the liquid 
crystal phase performs the switching among tristable states. 
The liquid crystal compounds which have the "anti" ferroelectric phase 
S*.sub.(3) showing the tristable states in a phase series are disclosed in 
Japanese Unexamined Patent Publication No. 1-316367, U.S. Pat. Nos. 
5,171,471 and 4,973,738, and European Patent No. 330,491A filed by the 
present inventors, and in Japanese Unexamined Patent Publication No. 
1-213390 filed by Ichihashi et al. Liquid crystal electrooptical devices 
utilizing the tristable states are proposed in Japanese Unexamined Patent 
Publication No. 2-40625 and U.S. Pat. No. 5,046,823. 
When "anti" ferroelectric liquid crystals are applied for displays, it is 
difficult to satisfy all of these required performance of characteristics 
1) the range of operation temperature, 
2) response time, 
3) spontaneous polarization, and 
4) hysteresis, 
with a single liquid crystal. Thus, the liquid crystals are usually used as 
a mixture of ten-odd kinds of liquid crystals. 
Particularly, in respect of the required performance 1) above, that is the 
range of operation temperature, development of "anti" ferroelectric liquid 
crystals is desired which show a stabilized display performance 
characteristic at an area of lower temperatures including room 
temperature. However, "anti" ferroelectric liquid crystals have not yet 
been found which stably develop "anti" ferroelectric S*.sub.(3) phase at 
the area of lower temperatures including room temperature and showing a 
high speed response. 
SUMMARY AND OBJECTS OF THE INVENTION 
An antiferroelectric liquid crystal compound according to the present 
invention is represented by the following formulae: 
##STR2## 
wherein R.sup.1 and R.sup.2 each is a C.sub.4 -C.sub.18 alkyl group, Rf is 
CF.sub.3 or C.sub.2 F.sub.5, X is O, COO or a single bond, and * 
identifies an optically active carbon atom. 
The object of the present invention is to provide a novel antiferroelectric 
liquid crystal compound, that is a liquid crystal compound having a phase 
S*.sub.(3) showing tristable states. 
Further object of the present invention is to provide a liquid crystal 
compound by which a high speed response can be expected and which is very 
efficient as a component constituting a mixed antiferroelectric liquid 
crystal.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention relates, first, to an antiferroelectric liquid 
crystal compound represented by the formula (I) 
##STR3## 
wherein R.sup.1 and R.sup.2 are independently selected from an alkyl group 
of C.sub.4 - C.sub.18, respectively, Rf is CF.sub.3 or C.sub.2 F.sub.5, X 
is O, COO, or a single bond, and * shows an optically active carbon atom. 
Preferable compounds in the first aspect of the present invention include 
antiferroelectric liquid crystal compounds represented by the following 
formulae (I-1) and (I-2): 
##STR4## 
wherein R.sup.1 and R.sup.2 are the same as those in the formula (I) 
above. 
The present invention relates, second, to an antiferroelectric liquid 
crystal compound represented by the formula (II) 
##STR5## 
wherein R.sup.1, R.sup.2, Rf, X and * are the same as those in the formula 
(I). 
Preferable compounds in the second aspect of the present invention include 
antiferroelectric liquid crystal compounds represented by the following 
formulae (II-1), (II-2), and (II-3): 
##STR6## 
wherein R.sup.1, R.sup.2, and * are the same as those in the formula (I). 
The present invention relates, third, to an antiferroelectric liquid 
crystal compound represented by the formula (III) 
##STR7## 
wherein R.sup.1, R.sup.2, Rf, X and * are the same as those in the formula 
(I). 
Preferable compounds in the third aspect of the present invention include 
antiferroelectric liquid crystal compounds represented by the following 
formula (III-1) 
##STR8## 
wherein R.sup.1, R.sup.2, and * are the same as those in the formula (I). 
The compounds of the present invention can be produced by methods wherein 
known synthetic procedures disclosed in N. Miyaura et al. [Synth. Commun. 
11, 513 (1981)] and others are used in combination. 
The objective compound (7-1) in Synthesis Example 1 explained below can be 
prepared by subjecting 4-alkoxy-1-bromobenzene and 2,3-difluorophenyl 
boronic acid to a coupling reaction to form compound (1-1), converting the 
compound (1-1) to a lithium compound (2-1) and then to a boronic acid 
compound (3-1), subjecting the compound (3-1) to a coupling reaction with 
4-bromobenzonitrile to form compound (4-1), subjecting the nitrile 
compound to hydrolysis to convert the nitrile group to carboxyl group to 
form compound (5-1), then converting the compound (5-1) to an acid 
chloride (6-1), and finally subjecting the compound (6-1) to 
esterification with an optically active alcohol such as 
1,1,1-trifluoro-2-alkanol. 
The compound (6-2) shown in Synthesis Example 2 can be prepared by using 
lithium-2,3-difluorobenzene as a starting material, subjecting it to an 
addition reaction of alkylaldehyde, dehydration reaction, and reduction 
reaction to form compound (1-2), converting the compound (1-2) to boronic 
acid compound (2-2), subjecting the compound (2-2) to a coupling reaction 
with 4-bromo-4'-cyanobiphenyl to form compound (3-2), subjecting the 
compound (3-2) to hydrolysis to convert the cyano group to carboxyl group 
to form compound (4-2), and then repeating the procedures similar to those 
in Synthesis Example 1. 
Further, Synthesis Example 3 explains a method for producing another 
compound of the present invention wherein anhydrous aluminium chloride and 
acetyl chloride are reacted to a terphenyl to perform a Friedel-Crafts 
reaction to form compound (1-3). The Friedel-Crafts catalysts used in the 
reaction of Synthesis Example 3 include aluminium bromide (AlBr.sub.3), 
iron trichloride (FeCl.sub.3), tin tetrachloride (SnCl.sub.4), and 
antimony pentachloride (SbCl.sub.5) in addition to anhydrous aluminium 
chloride (AlCl.sub.3). 
Then, the compound (1-3) is subjected to a haloform reaction with a 
hypohalaous compound such as sodium hypobromide (NaOBr) and sodium 
hypochlorite (NaOCl) to oxidize acetyl group (CH.sub.3 CO) to carboxyl 
group (COOH) to form compound (2-3). The compound (2-3) is converted to an 
ethyl ester derivative (3-3) by a conventional method. 
Further, Friedel-Crafts reaction mentioned above and then Baeyer-Villiger 
rearrangement are conducted to form compound (5-3) through compound (4-3). 
Next, hydrolysis is performed by using a base such as potassium hydroxide 
or sodium hydroxide to form compound (6-3). The hydroxyl group and 
carboxyl group in the compound (6-3) are converted to methoxymethyloxy 
group and ethyl ester group, respectively, to form compound (8-3) through 
compound (7-3). 
Then, the ethyl ester group is converted back to carboxyl group by using a 
base such as potassium hydroxide to form compound (9-3), and the compound 
(9-3) is subjected to esterification by using an optically active 
1,1,1-trifluoro-2-alkanol and a dehydration-condensation agent to form 
compound (10-3). The dehydration-condensation agent includes 
dicyclohexylcarbodiimide(DCC)-aminopyridine compounds, 
2-chloro-1,3,5-trinitrobenzene and pyridine compounds, and 
N,N'-carbonyldiimidazole. 
Then, the methoxymethyloxy group in the compound (10-3) is converted to 
hydroxyl group with an acid such as hydrogen chloride at an ambient 
temperature and then reacted with alkanoylchloride 
##STR9## 
to produce the objective compound (12-3). 
The same compound as the compound (12-3) can also be produced by methods 
wherein known synthetic procedures disclosed in N. Miyaura et al. [Synth. 
Commum. 11, 513 (1981)] and others are used in combination. 
That is, in Synthesis Example 4, compound (1-4) is prepared by reacting 
4-bromoanisole with triisopropylborate at a low temperature below 
-50.degree. C. Then, the compound (1-4) is subjected to a coupling 
reaction with 4-bromo-4'-cyanobiphenyl to form compound (2-4). The 
compound (2-4) is subjected to hydrolysis in the presence of a base such 
as potassium hydroxide in a water-ethanol solution to convert the nitrile 
group to carboxyl group to prepare compound (3-4). The compound (3-4) is 
reacted with an acid to convert the methoxy group to hydroxyl group to 
form compound (4-4) and then the compound (4-4) is subjected to a reaction 
with alkanoylchloride (R.sup.1 COCl) to form compound (5-4). 
Further, the compound (5-4) is converted to acid chloride (6-4) and the 
compound (6-4) is subjected to esterification with an optically active 
alcohol such as 1,1,1-trifluoro-2-alkanol to provide the objective 
compound (7-4). 
SYNTHESIS EXAMPLE 1 
##STR10## 
SYNTHESIS EXAMPLE 2 
##STR11## 
SYNTHESIS EXAMPLE 3 
##STR12## 
SYNTHESIS EXAMPLE 4 
##STR13## 
EXAMPLE 
The present invention will now be described in further detail with 
reference to Examples and comparative Examples. However, it should be 
understood that the present invention is by no means restricted by such 
Specific Examples. 
Example 1 
4-n-octyloxy-2,3-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphen 
yl 
##STR14## 
[1] Synthesis of 
##STR15## 
After 7.5 g of o-difluorobenzene was dissolved in 80 ml of dried 
tetrahydrofuran (THF), the solution thus formed was cooled down to 
-70.degree. C. under a nitrogen atmosphere and then added dropwise with 42 
ml of butyllithium (1.6 mol/liter hexane solution) at a temperature lower 
than -55.degree. C. The solution was continuously stirred at the same 
temperature for 1.5 hours and added dropwise with a THF solution 
containing 24.8 g of triisopropylborate at a temperature of -65.degree. C. 
to -60.degree. C. After the dropping of the solution was finished, the 
solution was continuously stirred at an ambient temperature for 12 hours, 
added further with 60 ml of a 10% aqueous hydrochloric acid solution, and 
continuously stirred for 1 hour. The reaction mixture thus obtained was 
subjected to extraction with an ether, washed with water, dried, and 
subjected to distillation under a reduced pressure to separate the solvent 
to obtain 9.0 g of 2,3-difluorophenyl boronic acid. 
The boronic acid in an amount of 9.0 g was dissolved in 60 ml of an ether, 
and the solution thus formed was added dropwise with 60 ml of a 10% 
aqueous hydrogen peroxide while being refluxed under a heated condition. 
After the dropping of the aqueous hydrogen peroxide was finished, the 
reflux under a heated condition was further continued for 2 hours. Then, 
the ether layer was separated with a separating funnel, washed with water, 
dried, and then subjected to distillation under a reduced pressure to 
separate the solvent to obtain 7.1 g of 2,3-difluorophenol. 
After 7.1 g of 2,3-difluorophenol was dissolved in 100 ml of acetone, the 
solution thus formed was added with 17 g of potassium carbonate (K.sub.2 
CO.sub.3) and 12.0 g of n-octylbromide, heated to reflux for 8 hours, and 
then subjected to distillation under a reduced pressure to separate 
acetone. The residue was added with 100 ml of an ether and subjected to 
extraction. The insoluble materials were separated by filtration, washed 
with a 10% aqueous sodium hydroxide solution and water in turn. The 
solvent was separated by distillation under a reduced pressure to obtain 
15 g of a product. The product was purified by a silica gel column 
chromatography to obtain 12.1 g of 2,3-difluoro-1-n-octyloxybenzene. 
[2] Synthesis of 
##STR16## 
After 12.1 g of the compound synthesized in [1] above was dissolved in 60 
ml of a dried THF, the solution thus formed was cooled down to -70.degree. 
C., added dropwise with 32 ml of butyllithium, and continuously stirred at 
the same temperature for 2 hours. Then, the solution was added dropwise 
with a THF solution containing 18.8 g of triisopropylborate at a 
temperature of lower than -60.degree. C. and continuously stirred at an 
ambient temperature for 12 hours. Then, the solution was further added 
with 60 ml of a 10% aqueous hydrochloric acid solution and continuously 
stirred for 1 hour. The reaction mixture thus formed was subjected to 
extraction with an ether, washed with water, dried, and subjected to 
distillation under a reduced pressure to separate the solvent to obtain 
13.2 g of 4-n-octyloxy-2,3-difluorophenyl boronic acid. 
[3] Synthesis of 
##STR17## 
To 15 ml of ethanol was added 3.69 g of the 4-n-octyloxy-2,3-difluorophenyl 
boronic acid obtained in [2] above to prepare a solution (A). The solution 
(A) was added to a mixture of 2.58 g of 4-bromo-4'-cyanobiphenyl, 400 mg 
of tetrakis(triphenylphosphine)palladium(0), 36 ml of benzene, and 36 ml 
of an aqueous sodium carbonate (Na.sub.2 CO.sub.3) solution (2 mol/liter). 
After the solution thus formed was stirred for 12 hours while being 
heated, the solution was cooled down to 5.degree. C., and the crystals 
thus precipitated were separated by filtration. The crystals thus obtained 
were dissolved in a mixed solvents of n-hexane and ethyl acetate (10:2), 
subjected to purification with a silica gel column chromatography, 
recrystallized from methylene chloride-hexane to obtain 2.95 g of 
4-n-octyloxy-2,3-difluoro-4"-cyano-p-terphenyl. 
[4] Synthesis of 
##STR18## 
A mixture of 2.46 g of the terphenyl compound obtained in [3] above, 250 ml 
of ethanol, and 9 g of potassium hydroxide was stirred for 72 hours while 
being heated, added further with 10 g of acetic acid, and continuously 
stirred for 2 hours while being heated. The solution was cooled to 
precipitate crystals, and the crystals thus precipitated were separated by 
filtration, washed with water, and dried to obtain 2.38 g of 
4-n-octyloxy-2,3-difluoro-4"-carboxyl-p-terphenyl. 
[5] Synthesis of 
##STR19## 
A mixture of 2.35 g of the terphenyl compound obtained in [4] above, 20 ml 
of methylene chloride, 3 ml of thionyl chloride (SOCl.sub.2), and few 
drops of dimethyl formamide (DMF) was heated at 40.degree. C. for 2 hours. 
After the solvents were separated by distillation, the compound was 
dissolved in 30 ml of methylene chloride. The solution thus formed was 
added dropwise to 30 ml of methylene chloride solution containing 1.04 g 
of (R)-1,1,1-trifluoro-2-octanol, 0.69 g of dimethylaminopyridine (DMAP), 
and 0.58 g of triethylamine. After the dropping of the methylene chloride 
solution was finished, the resulting solution was continuously stirred at 
an ambient temperature for 4 hours. The reaction liquid thus obtained was 
washed with a diluted aqueous hydrochloric acid solution and water in 
turn, subjected to distillation to separate the solvent. The residue thus 
obtained was subjected to purification by a silica gel column 
chromatography using a mixed solvents of n-hexane and ethyl acetate (10:1) 
and by recrystallization to obtain 1.70 g of 
4-n-octyloxy-2,3-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphe 
nyl. 
The phase transition temperatures (.degree. C.) of the terphenyl compound 
thus prepared observed with a microscope equipped with a hot stage were as 
follows: 
##STR20## 
(The microscope used in Example 1 was also used for the determination of 
phase transition temperature in the following all Examples and Comparative 
Examples.) 
Example 2 
4-n-nonyloxy-2,3-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphen 
yl 
##STR21## 
Example 1 was repeated except that 12.2 g of n-nonylbromide was used 
instead of n-octylbromide in [1] in Example 1. 
The phase transition temperatures (.degree. C.) of the terphenyl compound 
obtained were as follows: 
##STR22## 
Example 3 
4-n-decyloxy-2,3-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphen 
yl 
##STR23## 
Example 1 was repeated except that 12.4 g of n-decylbromide was used 
instead of n-octylbromide in [1] in Example 1. 
The phase transition temperatures (.degree. C.) of the terphenyl compound 
obtained were as follows: 
##STR24## 
Example 4 
4-n-octyloxy-2,', 
3'-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR25## 
[1]Synthesis of 
##STR26## 
In 100 ml of acetone, 8.0 g of 4-bromophenol, 8.9 g of n-octylbromide, and 
13 g of potassium carbonate were heated to reflux for 12 hours. After the 
solvent was distilled off under a reduced pressure, the residue thus 
obtained was extracted with isopropyl ether, washed with a 5% aqueous 
sodium hydroxide solution and water in turn. The ether was distilled off, 
and the residue was purified by a silica gel column chromatography using a 
mixed solvents of n-hexane and diethyl ether (10:1) and subjected to 
distillation to obtain 8.4 g of 4-bromo-1-n-octyloxybenzene. 
To a mixture of 4.2 g of the 4-bromo-1-n-octyloxybenzene, 0.5 g of 
tetrakis(triphenylphosphine) palladium(0), 53 ml of benzene, and 53 ml of 
an aqueous sodium carbonate solution (2 mol/liter), 26 ml of ethanol 
containing 3.0 g of 2,3-difluorophenyl boronic acid synthesized by the 
same method as in [1] in Example 1 was added dropwise, and then the 
solution thus formed was heated to reflux for 5 hours. After the solution 
was cooled, it was added with 200 ml of an ether to extract the product, 
washed with water and dried. The solvent was distilled off under a reduced 
pressure. The residue thus obtained was purified by a silica gel column 
chromatography using a mixed solvents of n-hexane and diethyl ether (10:2) 
to obtain 2.8 g of 4-n-octyloxy-2', 3'-difluorobiphenyl. 
[2] Synthesis of 
##STR27## 
After 2.72 g of the 4-n-octyloxy-2', 3'-difluorobiphenyl was dissolved in 
20 ml of a dried THF, the solution thus formed was cooled down to 
-70.degree. C. under a nitrogen atmosphere and added dropwise with 5.5 ml 
of butyllithium (1.6 mol/liter hexane solution). The solution was 
continuously stirred at the same temperature for 2 hours, and then added 
dropwise with a THF solution containing 3.21 g of triisopropylborate. 
After the solution was stirred at an ambient temperature for 12 hours, it 
was added with 7.7 ml of a 10% aqueous hydrochloric acid solution and 
further stirred for 1 hour. Then, the same after-treatments as in [1] in 
Example 1 were repeated to obtain 2.27 g of 
4-(p-n-octyloxyphenyl)-2,3-difluorobenzene boronic acid. 
[3] Synthesis of 
##STR28## 
The boronic acid compound obtained in [2] above in an amount of 2.26 g and 
1.09 g of 4-bromobenzonitrile were subjected to the same procedures as in 
[3] in Example 1 to obtain 2.15 g of 4-n-octyloxy-2', 
3'-difluoro-4"-cyano-p-terphenyl. 
[4] Synthesis of 
##STR29## 
The procedures in [4] in Example 1 were repeated by using 2.15 g of the 
compound prepared in [3] above as a raw material to obtain 1.88 g of 
4-n-octyloxy-2', 3'- difluoro-4"-carboxyl-p-terphenyl. 
[5] Synthesis of 
##STR30## 
The procedures in [5] in Example 1 were repeated by using 1.88 g of 
4-n-octyloxy-2', 3'-difluoro-4"-carboxyl-p-terphenyl prepared in [4] above 
to obtain 1.64 g of 4-n-octyloxy-2', 
3'-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl. The 
terphnyl compound thus obtained was subjected to recrystallization from an 
anhydrous ethanol and used for the determination of phase transition 
temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
terphenyl compound were as follows: 
##STR31## 
Example 5 
4-n-nonyloxy-2', 
3'-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR32## 
Example 4 was repeated except that 13 g of n-nonylbromide was used instead 
of n-octylbromide in [1] in Example 4. 
The phase transition temperature (.degree. C.) of the terphenyl compound 
thus obtained were as follows: 
##STR33## 
Example 6 
4-n-decyloxy-2', 
3'-difluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR34## 
Example 4 was repeated except that 14 g of n-decylbromide was used instead 
of n-octylbromide in [1] in Example 4. 
The phase transition temperature (.degree. C.) of the terphenyl compound 
thus obtained were as follows: 
##STR35## 
Comparative Example 1 
4-n-octyloxy-3-fluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)p-terphenyl 
##STR36## 
[1] Synthesis of 
##STR37## 
To 50 ml of carbon disulfide in which 50 g of o-fluoroanisole was 
dissolved, a solution prepared by mixing 27 g of carbon dislufide with 
63.8 g of bromine was slowly added dropwise at a temperature of -5.degree. 
C. to 5.degree. C. in 1 hour with stirring. After the dropping of the 
solution was finished, it was further stirred at 5.degree. C. for 30 min, 
added with 125 ml of water, and subjected to extraction with chloroform. 
The chloroform layer was washed with an aqueous sodium thiosulfate 
(Na.sub.2 S.sub.2 O.sub.3) solution and an aqueous sodium 
hydrogencarbonate (NaHCO.sub.3) solution in turn. Then, the solvent was 
distilled off with an evaporator under a reduced pressure to obtain 70.9 
of 4-bromo-2-fluoroanisole. 
Then, 9.6 g of magnesium was added to 230 ml of THF, and the solution thus 
formed was slowly added dropwise with 70.9 g of the 
4-bromo-2-fluoroanisole obtained by the procedure mentioned above to 
prepare a Grignard reagent. The reagent was added dropwise to a mixture of 
123.8 g of triisopropyl borate and 391 ml of THF at a temperature of 
-60.degree. C. to -50.degree. C. with stirring. After the dropping of the 
reagent was finished, the solution was subjected to reaction at an ambient 
temperature for 2 hours, added with 242 ml of a 1N-aqueous hydrochloric 
acid solution, subjected to further reaction for 1 hour, extracted with an 
ether, washed with water, and concentrated under a reduced pressure to 
obtain 46.2 g of 4-methoxy-3-fluorobenzene boronic acid. 
[2] Synthesis of 
##STR38## 
To a mixture of 2.4 g of 4-bromo-4'-cyanobiphenyl, 0.37 g of 
tetrakis(triphenylphosphine)palladium(0), 15.2 ml of a 2N aqueous sodium 
carbonate solution, and 19.4 ml of benzene, a solution which was prepared 
by dissolving 1.9 g of 4-methoxy-3-fluoro-benzene boronic acid synthesized 
in [1] above in 14.4 ml of ethanol was slowly added dropwise with 
stirring, and the solution was subjected to reflux for 8 hours. After the 
reflux was finished, the solution was cooled, and the crystals thus 
precipitated were separated by filtration and washed with water and 
methanol in turn, and dried to obtain 2.5 g of 
4-methoxy-3-fluoro-4"-cyano-p-terphenyl. 
[3] Synthesis of 
##STR39## 
The 4-methoxy-3-fluoro-4"-cyano-p-terphenyl in an amount of 2.5 g obtained 
in [2] above was added with 200 ml of methylene chloride, and added slowly 
dropwise with stirring with a solution which was prepared by dissolving 8 
g of boron tribromide (BBr.sub.3) in 50 ml of methylene chloride, and the 
solution was subjected to reaction at an ambient temperature overnight. 
The solution was dispersed in 200 ml of water and extracted with THF. 
After the solvent was distilled off under a reduced pressure, the residual 
crystals were subjected to recrystallization from a mixed solvents of 
THF-methanol (10:1) to obtain 2.2 g of 
4-hydroxy-3-fluoro-4"-cyano-p-terphenyl. 
Then, a mixture of 1 g of the 4-hydroxy-3-fluoro-4"-cyano-p-terphenyl thus 
obtained, 0.77 g of n-octylbromide, 0.55 g of potassium carbonate, and 10 
ml of dimethyl formamide was subjected to reaction at 100.degree. C. for 1 
hour with stirring. After the reaction was finished, the solution was 
dispersed in 50 ml of water, subjected to extraction with ethyl acetate, 
washed with water, and subjected to distillation to separate the solvent 
under a reduced pressure to obtain solid materials. The solid materials 
were recrystallyzed from methanol to obtain 1.23 g of the objective 
compound. 
[4] Synthesis of 
##STR40## 
A mixture of 1,23 g of 4-n-octyloxy-3-fluoro-4"-cyano-p-terphenyl, 4.5 g of 
potassium hydroxide powders, and 123 ml of ethanol was refluxed for 72 
hours with stirring, added with 4.7 g of acetic acid, and further refluxed 
for 2 hours. After the reflux was finished, the solution was cooled to 
precipitate crystals. The crystals thus precipitated were separated by 
filtration, washed with water, and dried to obtain 1.2 g of 
4-n-octyloxy-3-fluoro-4"-carboxyl-p-terphenyl. 
[5] Synthesis of 
##STR41## 
A mixture of 1.2 g of the 4-n-octyloxy-3-fluoro-4"-carboxyl-p-terphenyl 
obtained in [4] above, 0.8 g of thionyl chloride, 20 ml of methylene 
chloride, and a catalytic amount of dimethyl formamide was subjected to 
reflux at 40.degree. C. for 2 hours. After the reflux was finished, the 
solution was concentrated under a reduced pressure, and then subjected 
several times to azeotropic distillation with toluene to separate 
unreacted thionyl chloride to obtain acid chloride materials. 
Then, 20 ml of methylene chloride solution containing the acid chloride 
materials mentioned above was slowly added dropwise, while being cooled 
with an ice water, to a mixed solution of 0.45 g of 
(R)-(+)-1,1,1-trifluoro-2-octanol [.alpha.] D.sup.20 =+25.6 (C=0.9960, in 
CHCl.sub.3), 0.3 g of dimethylaminopyridine (DMAP), 0.26 g of 
triethylamine, and 20 ml of methylene chloride. The solution was further 
subjected to reaction at an ambient temperature overnight. The reaction 
solution thus obtained was washed with a diluted aqueous hydrochloric acid 
solution and water in turn, the solvent was distilled off, and the residue 
was subjected to purification by a silica gel column chromatography using 
a mixed solvents of n-hexane and ethyl acetate (10:1) and by 
recrystallization from ethanol to obtain 1.7 g of 
4-n-octyloxy-3-fluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl. 
The terphenyl compound was further purified by recrystallization from an 
anhydrous ethanol for the determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
terphenyl compound were as follows: 
##STR42## 
Comparative Example 2 
4-n-nonyloxy-3-fluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR43## 
Comparative Example 1 was repeated except that 0.78 g of n-nonylbromide was 
used instead of n-octylbromide in [3] in Comparative Example 1. 
The phase transition temperature (.degree. C.) of the terphenyl compound 
thus obtained were as follows: 
##STR44## 
Comparative Example 3 
4-n-decyloxy-3-fluoro-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR45## 
Comparative Example 1 was repeated except that 0.79 g of n-decylbromide was 
used instead of n-octylbromide in [3] in Comparative Example 1. 
The phase transition temperature (.degree. C.) of the terphenyl compound 
thus obtained were as follows: 
##STR46## 
Comparative Example 4 
4-n-octyloxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR47## 
After 1.6 g of 4-n-octyloxyterphenyl-4"-carboxylic acid was heated with an 
excess amount of thionyl chloride under reflux condition for 6 hours, 
unreacted thionyl chloride was distilled off to obtain 
4-n-octyloxyterphenyl-4"-carboxylic acid chloride. 
To a solution prepared by dissolving the acid chloride mentioned above in 
50 ml of methylene chloride, another solution prepared by dissolving 0.7 g 
of 1,1,1-trifluoro-2-octanol, 0.4 g of triethylamine, and 0.1 g of 
dimethylaminopyridine in 50 ml of methylene chloride was slowly added 
while being cooled with ice, and the solution thus formed was subjected to 
reaction at an ambient temperature overnight. 
Then, the reaction liquid thus obtained was put in an ice water and 
extracted with methylene chloride. The methylene chloride layer was washed 
with a diluted aqueous hydrochloric acid solution, water, aqueous sodium 
carbonate solution, and water in turn, dried with anhydrous sodium 
sulfate, and subjected to distillation to separate the solvent to obtain a 
crude product. The crude product was purified by a silica gel column 
chromatography using a mixed solvents of n-hexane and ethyl acetate (10:1) 
to obtain 1.1 g of the objective optically active compound. The compound 
was further purified by recrystallization from anhydrous ethanol for the 
determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
compound were as follows: 
##STR48## 
Comparative Example 5 
4-n-octyloxy-4"-(1,1,1-trifluoro-2-decyloxycarbonyl-p-terphenyl 
##STR49## 
Comparative Example 4 was repeated except that 0.7 g of 
1,1,1-trifluoro-2-decanol was used instead of 1,1,1-trifluoro-2-octanol to 
obtain the objective compound. 
The phase transition temperature (.degree. C.) of the compound thus 
obtained were as follows: 
##STR50## 
Example 7 
4-n-octylcarbonyloxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR51## 
Synthesis of the objective compound was performed in the order as follows: 
##STR52## 
Synthesis of Compound 2: 
After a mixture of 172 g of terphenyl, 860 ml of benzene, and 353 g of 
acetyl chloride was cooled to -5.degree. C., it was added with a total of 
200 g of anhydrous aluminium chloride in few instalments, and subjected to 
reaction at -5.degree. C. for 1 hour and further at 10.degree. C. for 1 
hour. The solid materials thus formed were separated by filtration, washed 
with a total of 4 liter of methanol in few instalments, and then 
recrystallized from chloroform to obtain 121 g of 4-acetyl-p-terphenyl, 2. 
The yield was 59%. 
Synthesis of Compound 3: 
After 50 g of the 4-acetyl-p-terphenyl obtained in the synthesis of 
compound 2 above was dissolved in 2 liter of dioxane, the solution thus 
formed was added with an aqueous sodium hypobromite solution (prepared 
from 151 g of bromine (Br.sub.2) and 780 g of a 20% aqueous sodium 
hydroxide solution) and subjected to reaction at 60.degree. C. for 2 
hours. After the solution was cooled down to a room temperature, it was 
added with an aqueous hydrochloric acid solution to make it acidic. The 
crystals thus precipitated were separated by filtration, washed with 
water, added in 3 liter of THF, and heated to dissolve. After the 
insoluble materials were separated by filtration, the filtrate was 
concentrated to 500 ml, and the crystals thus precipitated were separated 
by filtration to obtain 44 g 4-carboxyl-p-terphenyl, 3. The yield was 88%. 
Synthesis of Compound 4: 
After 44 g of the 4-carboxyl-p-terphenyl obtained in the synthesis of 
compound 3 was heated to reflux with 450 ml of chloroform and 450 ml of 
thionyl chloride for 4 hours, the solvent and thionyl chloride were 
distilled off under a reduced pressure. The residue was added with 3 liter 
of a 3% triethylamine ethanol solution, and heated for 12 hours with 
stirring. After the solvent was distilled off under a reduced pressure, it 
was added with 2 liter of THF. The insoluble materials were separated by 
filtration, the filtrate was subjected to distillation under a reduced 
pressure to precipitate crystals, and the crystals were washed with 
benzene to obtain 35 g of 4-carboxyl-p-terphenyl ethyl ester, 4. The yield 
was 71%. 
Synthesis of Compound 5: 
After 29.2 g of the ester obtained in the synthesis of compound 4 above was 
dissolved in 290 ml of methylene chloride, it was added with 30.9 g of 
anhydrous aluminium chloride, added dropwise with 18.3 g of acetyl 
chloride, and then subjected to reaction by heating to reflux for 4 hours. 
The reaction liquid thus obtained was dispersed in an ice water, extracted 
with chloroform, washed with water, dried, and then subjected to 
distillation under a reduced pressure to separate the solvent. The residue 
was recrystallized from a mixed solvents of chloroform and methanol to 
obtain 24.1 g of 4-acetyl-4"-carboxyl-p-terphenyl ethyl ester, 5. The 
yield was 72%. 
Synthesis of Compound 6: 
After 27.0 g of the ester obtained in the synthesis of compound 5 above was 
dissolved in 540 ml of methylene chloride, it was added with 121 g of 
formic acid, 46 g of anhydrous acetic acid, and 15 g of a concentrated 
sulfuric acid, and then added dropwise with a 35% aqueous hydrogen 
peroxide while being cooled with ice. After the solution was heated under 
reflux condition for 8 hours, the solution was dispersed in an ice water, 
extracted with chloroform, washed with water, dried, and subjected to 
distillation under a reduced pressure to separate the solvent. The residue 
was recrystallized from a mixed solvents of chloroform and methanol to 
obtain 16.5 g of 4-acetyloxy-4"-carboxyl-p-terphenyl ethyl ester, 6. The 
yield was 58%. 
Synthesis of Compound 7: 
After 16.5 g of the compound obtained in the synthesis of compound 6 above 
was dissolved in 500 ml of ethanol, it was added with 34 g of a 50% 
aqueous potassium hydroxide solution, and refluxed for 5 hours. The 
solution was added with an aqueous hydrochloric acid solution to adjust 
its pH to 1 and further refluxed for 1 hour. The solution was cooled down 
to a room temperature to precipitate crystals, and the crystals thus 
precipitated were separated by filtration, washed with water, and dried to 
obtain 12.5 g of 4-hydroxy-4"-carboxyl-p-terphenyl, 7. The yield was 94%. 
Synthesis of Compound 8: 
After a mixture of 25.0 g of the compound obtained in the synthesis of 
compound 7 above, 1 liter of ethanol, 1 liter of THF, and 100 g of a 
concentrated sulfuric acid was heated for 3 hours with stirring, the 
insoluble materials were separated by filtration while being heated. The 
filtrate was allowed to stand to cool, and the crystals thus precipitated 
were separated by filtration, washed with water, and dried to obtain 23.1 
g of 4-hydroxy-4"-carboxyl-p-terphenyl ethyl ester, 8. The yield was 85%. 
Synthesis of Compound 9: 
The ethyl ester obtained in the synthesis of compound 8 above in an amount 
of 13.7 g, 13.0 g of chloromethyl methyl ether, and 22.2 g of anhydrous 
potassium carbonate were heated at 100.degree. C. in 70 ml of dimethyl 
formamide for 24 hours with stirring. After the solution thus formed was 
cooled, it was added with 500 ml of water, and the crystals thus 
precipitated were separated by filtration. The crystals were dissolved in 
600 ml of THF, the insoluble materials were separated by filtration, and 
the solution was subjected to distillation under a reduced pressure to 
separate the solvent. The residue was added with methanol, and the 
crystals thus precipitated were separated by filtration, and dried to 
obtain 10.1 g of 4-methoxymethyloxy-4"-carboxyl-p-terphenyl ethyl ester, 
9. The yield was 64%. 
Synthesis of Compound 10: 
The compound obtained in the synthesis of compound 9 above in a amount of 
22.8 g, 950 ml of ethanol, and 64 g of a 50% aqueous potassium hydroxide 
solution were heated to reflux for 4 hours. The reaction mixture thus 
obtained was added with a diluted aqueous hydrochloric acid solution to 
adjust its pH to 3 to 4, and the crystals thus precipitated were separated 
by filtration, washed with water, and dried to obtain 21.0 g of 
4-methoxymethyloxy-4"-carboxyl-p-terphenyl, 10. The yield was 100%. 
Synthesis of Compound 11: 
After 11.1 g of the compound obtained in the synthesis of compound 10 above 
was dissolved in 200 ml of methylene chloride, it was added with 7.0 g of 
(R)-(+)-1,1,1-trifluoro-2-octanol, 50 mg of dimethylaminopyridine, and 7.0 
g of ethylene dichloride EDC.HCl, and stirred at an ambient temperature 
for 24 hours. The reaction liquid thus obtained was washed with water, 
dried, and subjected to distillation under a reduced pressure to separate 
the solvent. The residue was purified by a silica gel column 
chromatography and further recrystallized from methanol to obtain 8.0 g of 
4-methoxymethyloxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl, 
11. The yield was 48%. 
Synthesis of Compound 12: 
After 8.0 g of the compound obtained in the synthesis of compound 11 above 
was dissolved in 110 ml of acetone, it was added with 17 ml of a 
concentrated hydrochloric acid solution and stirred at an ambient 
temperature for 2 hours. The reaction liquid thus obtained was added with 
300 ml of water, and cooled with ice. The crystals thus precipitated were 
separated by filtration. After the crystals were washed with a 10% hydrate 
acetone, they were dried to obtain 6.5 g of 
4-hydroxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl, 12. The 
yield was 89%. 
Synthesis of Compound 13: 
After 2.0 g of the compound obtained in the synthesis of compound 12 above 
was dissolved in 20 ml of methylene chloride, it was added with 0.54 g of 
triethylamine, and added dropwise with 1.0 g of nonanoylchloride. The 
solution was stirred at an ambient temperature for 12 hours, washed with a 
diluted aqueous hydrochloric acid solution, saturated salt water, 
saturated aqueous sodium bicarbonate solution, and salt water in turn, 
dried, and subjected to distillation under a reduced pressure to separate 
the solvent. The crude product thus obtained was purified first by a 
silica gel column chromatography, next by an ODS flash chromatogrphy, and 
then by recrystallization from ethanol to obtain 1.2 g of 
4-n-octylcarbonyloxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl, 
13. The compound was further purified by recrystallization from anhydrous 
ethanol for the determination of phase transition temperature. The yield 
was 46%. 
The phase transition temperature (.degree. C.) of the finally purified 
compound were as follows: 
##STR53## 
Example 8 
4-n-nonylcarbonyloxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR54## 
Example 7 was repeated except that 1.0 g of decanoylchloride was used as a 
raw material instead of 1.0 g of nonanoylchloride in the synthesis of 
compound 13 in Example 7 to obtain 1.1 g of the objective compound. The 
compound was further purified by recrystallization from anhydrous ethanol 
for the determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
compound were as follows: 
##STR55## 
Example 9 
4-n-decylcarbonyloxy-4"-(1,1,1-trifluoro-2-octyloxycarbonyl)-p-terphenyl 
##STR56## 
Example 7 was repeated except that 1.1 g of undecanoyl was used as a raw 
material instead of 1 g of nonanoylchloride in the synthesis of compound 
13 in Example 7 to obtain 1.2 g of the objective compound. The compound 
was further purified by recrystallization from anhydrous ethanol for the 
determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
compound were as follows: 
##STR57## 
Example 10 
4-n-octylcarbonyloxy-4"-(1,1,1-trifluoro-2-decyloxycarbonyl)-p-terphenyl 
##STR58## 
Example 7 was repeated except that 7.0 g of 
(R)-(+)-1,1,1-trifluoro-2-decanol was used instead of 
(R)-(+)-1,1,1-trifluoro-2-octanol used in the synthesis of the compound 11 
in Example 7 to obtain 1.1 g of the objective compound. The compound was 
further purified by recrystallization from anhydrous ethanol for the 
determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
compound were as follows: 
##STR59## 
Example 11 
4-n-nonylcarbonyloxy-4"-(1,1,1-trifluoro-2-decyloxycarbonyl)-p-terphenyl 
##STR60## 
Example 10 was repeated except that 1.0 g of decanoylchloride was used 
instead of 1.0 g of nonanoylchloride to obtain 1.1 g of the objective 
compound. The compound was further purified by recrystallization from 
anhydrous ethanol for the determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
compound were as follows: 
##STR61## 
Example 12 
4-n-carbonyloxy-4"-(1,1,1-trifluoro-2-decyloxycarbonyl)-p-terphenyl 
##STR62## 
Example 10 was repeated except that 1.2 g of undecanoylchloride was used 
instead of 1.0 g of nonanoylchloride to obtain 1.2 g of the objective 
compound. The compound was further purified by recrystallization from 
anhydrous ethanol for the determination of phase transition temperature. 
The phase transition temperature (.degree. C.) of the recrystallized 
compound were as follows: 
##STR63## 
Example 13 
The liquid crystal compound obtained in Example 4 was filled in the form of 
an isotropic phase to a liquid crystal cell having a cell thickness of 1.9 
.mu.m and having a rubbed polyimide oriented film on an ITO electrode 
substrate to prepare a liquid crystal thin film cell. 
The liquid crystal cell thus prepared was arranged on a polarizing 
microscope equipped with a photomultiplier where 2 polarizing plates were 
orthogonally arranged with each other in such a state that the visual 
field is dark when voltage is 0 V. 
The liquid crystal cell was slowly cooled down to temperature, T.sub.CA 
(.degree. C.) where phase S*.sub.(3) appeared. Then, the liquid crystal 
cell was further cooled down slowly to temperatures lower than the 
T.sub.CA (.degree. C.) and a pulse voltage as shown in FIG. 5(A) was 
applied at the temperatures. 
The response times, .tau..sub.r, .tau..sub.d, and .tau. which were obtained 
from the change in the transmittance (%) as shown in FIG. 5(B) are shown 
in FIG. 6. 
Definition of the response times will be understood from the following: 
The response time .tau..sub.r for the transition from the first stable 
state (dark state) to the second stable state (bright state), the response 
time .tau..sub.d for the transition from the second stable state (bright 
state) to the first stable state (dark state), and response time .tau. for 
the transition from the second stable state (bright state) to the third 
stable state (bright state) through the first stable state were measured. 
Smaller response times, .tau..sub.r, .tau..sub.d, and .tau. to electric 
field means a desirable more rapid response. 
Example 14 
Example 13 was repeated except that the compound obtained in Example 7 was 
used instead of the compound obtained in Example 4. 
The response times measured are shown in FIG. 7. 
Example 15 
The liquid crystal cell having the same structure as that in Example 14 
wherein the liquid crystal compound obtained in Example 7 was used was 
slowly cooled down at a temperature gradient of 0.1.degree. to 1.0.degree. 
C./min to the temperature, T.sub.CA (.degree. C.) where the S*.sub.(3) 
appeared. Then, the liquid crystal cell was further cooled down slowly to 
temperatures lower than the T.sub.CA (.degree. C.) and a pulse voltage as 
shown in FIG. 5A was applied. 
The response times, .tau..sub.r, .tau..sub.d, and .tau. which were obtained 
from the change in the transmittance (%) as shown in FIG. 5B are shown in 
FIG. 8. 
Example 16 
Example 15 was repeated except that the liquid crystal compound obtained in 
Example 10 was used instead of the liquid crystal compound obtained in 
Example 7. 
The response times measured are shown in FIG. 9. 
Comparative Example 6 
Example 15 was repeated except that the liquid crystal compounds obtained 
in comparative Examples 4 and 5, respectively, were used instead of the 
liquid crystal compound obtained in Example 7. 
The response times measured are also shown in FIGS. 8 and 9, respectively.