JPH07286178A - 4- (2-phenylethyl) bicyclohexane derivative - Google Patents

Abstract

PURPOSE:To obtain a mixture excellent in compatibility with other liquid crystal compounds, causing no crystal deposition even in the low-temperature range, useful as e.g. a structural material for liquid crystal displays, composed of plural number of each specific phenylethylbicyclohexane derivatives. CONSTITUTION:The objective mixture is composed of at least two kinds of compound of formula I [R<1> is a 1-12C alkyl; X<1> to X<4> each is H or deuterium (D), at least one of them being D; Y<1> and Y<2> each H or F; Z is H, F, Cl, cyano, R<2>, OR<2>, OCN, CF3, OCF3, OCF2H OCH2CF3 (R<2> is a 1-12C alkyl or a 2-12C alkenyl); the cyclohexane ring stands at trans-configuration] which meet the following requirements: (1) the number of D(s) and/or the substitution site(s) in X<1> to X<4> differing from each other, and (2) R<1>, Y<1>, Y<2> and Z each is identical with each other; or, the objective mixture is composed of at least two kinds of compound of formula II which meet the following requirements: (1) the same as the above, and (2) R<1> is identical with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixture composed of a liquid crystal compound having a deuterium atom, which can improve the characteristics of an electro-optical liquid crystal display material, and more specifically, it does not precipitate crystals in the low temperature region for a long period of time. 4-has excellent effects
A mixture of (2-phenylethyl) bicyclohexane derivatives, and 4'-alkylbicyclohexane-4 having a deuterium atom useful as an intermediate for the preparation of this mixture.
-A mixture of carbaldehyde and a mixture of 4'-alkylbicyclohexyl-4-ethanal.

[0002]

2. Description of the Related Art Liquid crystal display devices have come to be used in watches, calculators, various measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions and the like. Typical liquid crystal display methods are TN (twisted nematic) type, STN (super twisted nematic) type, DS (dynamic light scattering) type, GH (guest host) type, and FLC (ferroelectric liquid crystal). ) And the like, and as the drive system, the conventional static drive has become more common and multiplex drive has become popular.
An active matrix drive using an ansistor) or MIM (Metal-Insulator-Metal) has been put to practical use.

Liquid crystal compositions are required to have various characteristics according to these display systems and drive systems. (1) The liquid crystal phase has a wide temperature range from low temperature to high temperature, and can be driven in a wide temperature range. (2) Low threshold voltage, low voltage driving, and (3) low viscosity and high-speed response are common to all liquid crystal compositions regardless of display method or driving method. It is an important characteristic that is required.

Up to the present, no liquid crystal compound which alone satisfies such required properties is known, and at present, a liquid crystal composition having desired properties is obtained by mixing various liquid crystal compounds. .

Among these, in order to obtain a liquid crystal composition exhibiting a liquid crystal phase in a wide temperature range, a method of mixing various liquid crystal compounds having different temperature regions of the liquid crystal phase is used. When using such a technique, for example, a nematic phase of the liquid crystal composition - isotropic liquid phase transition temperature mixing ratio, the high T _NI point crystal compound when increasing (hereinafter, referred to as T _NI point.) Should be higher. However, such compounds are of a nematic phase lower limit temperature (hereinafter, referred to as T _CN point.) So is high, T _CN point inevitably resulting liquid crystal composition may cause increased, and crystallized at a low temperature deposition In many cases, it cannot be used as a practical liquid crystal composition.

From the above, when preparing a practical liquid crystal composition in which the temperature range of the nematic phase is wide from a low temperature region to a high temperature region, a liquid crystal compound having a low melting point and a nematic phase at room temperature are generally used. The temperature range of the liquid crystal phase is adjusted by empirically mixing 10 to 20 kinds of the liquid crystal compound shown and a compound having a high T _NI point.

However, at the same time as expanding the temperature range, it is necessary to optimize the electro-optical characteristics and the viscosity in accordance with the purpose of use, so that other liquid crystal compounds as constituent components of the liquid crystal composition are It cannot be used unless it satisfies various required properties to some extent, including compatibility with compounds. Therefore, of the many liquid crystal compounds, the selection range of compounds that can be used in preparing a practical liquid crystal composition is considerably limited.

For example, liquid crystal compositions for active matrix driving systems such as TFT and MIM, which are becoming the mainstream of liquid crystal display devices at present, are required to have the above-mentioned characteristics (1) to (3). In addition to the fourth characteristic, it is further required (4) to have a high voltage holding ratio. This is because if the voltage holding ratio of the liquid crystal composition is low, a flicker phenomenon occurs in which the luminance of the pixel that should have been driven changes.

In general, in order to increase the voltage holding ratio of a liquid crystal composition, it must be chemically stable against heat and light in the device and have a high specific resistance value. As a result of various investigations on liquid crystal compounds satisfying such required characteristics, among the compounds conventionally used for TN and STN, liquid crystal compounds having an ester group, a cyano group, a pyrimidine ring, a dioxane ring, or the like have a voltage holding property. It was found to be unsuitable for active matrix as it reduces the rate. Further, also in the active matrix driving method, the display method is the same as the conventional TN display method, and therefore it is essential that the dielectric anisotropy (Δε) of the liquid crystal composition is positive as a whole. However, among the conventionally used liquid crystal compounds having a positive Δε (hereinafter referred to as p-type liquid crystal compounds), those having a relatively large Δε also lower the voltage holding ratio. Was not suitable for active matrix driving.

[0010]

[Chemical 4]

(In the formula, R represents an alkyl group.) Therefore, at present, in order to make Δε of the liquid crystal composition a positive and appropriate value, a compound having a fluoro group or a chloro group as a functional group, for example, Such a p-type liquid crystal compound is used as a material for an active matrix.

[0012]

[Chemical 5]

[0013]

[Chemical 6]

(In the formula, R represents an alkyl group and R'represents an alkyl group, an alkenyl group or an alkoxyalkyl group.) However, these compounds are used to achieve the electro-optical characteristics required for active matrix driving. However, since many liquid crystal compounds used for the active matrix have a relatively high T _NI point, it is very difficult to prepare a liquid crystal composition having a sufficiently low T _CN point.

In order to solve this problem, among the above-mentioned fluoro compounds, several homologues having the same skeleton and different from each other in the range of 2 to 7 carbon atoms of the terminal alkyl group are added. Is used to lower the T _CN point of the liquid crystal composition. However, in this method, the T _CN point does not decrease so much, and the viscosity tends to increase as the number of carbon atoms of the terminal alkyl group increases, so that the response characteristic of the above (3) is deteriorated. I will end up.

As described above, no active liquid crystal composition satisfying all of the above-mentioned characteristics (1) to (4) has been obtained so far, and the active matrix liquid crystal composition is (2). Priority is given to satisfying the characteristics of (4) to (4), and in the temperature range of (1), even if the T _CN point is not sufficiently low, it is unavoidable to use it. Many are easy to deposit.

In addition to the characteristics (1) to (3) described above, the liquid crystal composition used in the STN liquid crystal display device has a fourth characteristic (5) the elastic constant ratio of the liquid crystal composition ( K ₃₃ / K ₁₁ ) is large, and it is required to achieve high contrast. Further, since the STN display system is often applied to general-purpose devices such as laptop computers, the low threshold voltage of (2) is also an important required characteristic. In order to reduce the threshold voltage of the liquid crystal composition, it is necessary to increase the dielectric anisotropy Δε of the liquid crystal composition or decrease the elastic constant K according to the following formula.

[0018]

[Equation 1]

(In the formula, k represents a proportional constant, V _th represents a threshold voltage, and Δε represents a dielectric anisotropy.) Here, as a liquid crystal compound having a very large Δε, for example, the following formula is used. However, when a large amount of a compound having too large Δε is used, it often causes a problem such as an increase in current value, and when actually used as a liquid crystal display device, there is a problem in reliability. .

[0020]

[Chemical 7]

(In the formula, R represents an alkyl group.) The liquid crystal composition having a small elastic constant has a matrix liquid crystal composed of a p-type liquid crystal compound, a high T _NI point, and a relatively small elastic constant. Tri-ring liquid crystal compound or tri-ring system p of liquid crystal compound having negative Δε (hereinafter referred to as n-type liquid crystal compound)
Formed liquid crystal compounds are prepared by a method of mixing. As a p-type liquid crystal compound having a large elastic constant ratio K ₃₃ / K ₁₁ ,
For example, the compound of the following formula is used.

[0022]

[Chemical 8]

(In the formula, R ′ represents an alkyl group, an alkenyl group or an alkoxyalkyl group, and X represents a hydrogen atom or a fluorine atom.) Therefore, in order to satisfy the threshold voltage characteristic and the contrast characteristic in STN, When such a p-type liquid crystal compound is mixed with the above-mentioned tricyclic p-type or n-type liquid crystal compound, there is a problem that crystals tend to precipitate in a low temperature region. Therefore, as in the case of the active matrix, many kinds of homologues having the same skeleton and different carbon atoms of R ′ are added, or when R ′ is an alkenyl group, the position of the double bond is Are added to reduce the T _CN point of the resulting liquid crystal composition.

However, in such a method, due to the difference in the number of carbon atoms or the position of the double bond,
The value of the elastic constant ratio K ₃₃ / K ₁₁ of the compound also differs greatly, eventually, the elasticity of the liquid crystal composition obtained constant ratio K ₃₃ / K ₁₁
In many cases, and the contrast is often reduced. In addition, the method of adding a homologue has a problem in that the T _CN point can be lowered only in addition to increasing viscosity and slowing the response speed. It is very difficult to design the composition of a product.

At present, although a liquid crystal composition for STN having a low threshold voltage of about 1.2 V is prepared, the elastic constant ratio K ₃₃ / K ₁₁ is as described above. Since it is not large enough, it can be driven at low voltage and S
No TN liquid crystal display device has been manufactured so far.

As described above, as the liquid crystal composition having a wide temperature range of the liquid crystal phase of the above (1),
Although it is required that the liquid crystal composition has a high T _NI point as well as a low T _CN point, in reality, even if the temperature is higher than the T _CN point, crystals will not be formed if stored in a low temperature region for a long period of time. Since a large number of materials are deposited, a highly reliable liquid crystal display device does not have crystals deposited in the liquid crystal composition for a long period of time even in a low temperature region, and there is no display defect due to environmental temperature change on the entire display screen. Required. T _CN point of liquid crystal compositions, because often mixed system composition comprised of individual liquid crystal simple substance exhibits supercooling, T _CN point solidified or glassy state of the liquid crystal composition in a liquid nitrogen or the like Crystallization is performed by cooling to a sufficiently low temperature (for example, -70 ° C), and then the transition temperature from the solid to the nematic phase is measured while gradually increasing the temperature, and this is taken as the T _CN point.

However, in the case of a practical liquid crystal composition having 10 to 20 kinds of components, since it is not a eutectic mixture,
Even if the crystal is stored at a temperature higher than the lower limit temperature of the nematic phase based on the above-described measurement, crystals are often precipitated, which eventually narrows the drivable temperature range.
For example, it is not uncommon for crystals to precipitate at room temperature even though the T _CN point is -70 ° C. Further, as described above, it is required for a vehicle or an aircraft to stably show a nematic phase in a wide temperature range from -40 ° C to 110 ° C, but even when stored at a low temperature of -55 ° C. A liquid crystal composition in which crystals do not precipitate has not been obtained so far. Therefore, even a liquid crystal composition that is actually widely used for in-vehicle use may have crystals precipitated in about one week when stored at −25 ° C., for example. From such an example as well, even if the T _CN point of the liquid crystal composition is extremely low, it does not necessarily mean that crystals do not precipitate at a higher temperature.
_In order to obtain high reliability, it is necessary not to have a low _CN point but to prevent crystals from precipitating even in a low temperature region.

As described above, the liquid crystal composition is prepared by mixing various liquid crystal compounds so as to be adapted to the display system and the driving system. However, the liquid crystal compounds currently used alone have improved characteristics. Is limited. In particular,
A general-purpose liquid crystal composition is often designed with a focus on satisfying electro-optical characteristics. However, among such general-purpose liquid crystal compositions, particularly TF
In the liquid crystal composition for the active matrix driving system such as T and MIM and the liquid crystal composition for the STN liquid crystal display device, the temperature range of the liquid crystal phase of (1) is wide, and the crystal is formed in the low temperature region. Almost no material has high reliability in practice because it does not precipitate.

A general-purpose liquid crystal composition which substantially satisfies the above characteristics (2) to (5) has different temperatures depending on the purpose of use, but crystals are deposited for about one month even if stored at a relatively low temperature. If not, it is recognized as a highly reliable practical liquid crystal.

However, when such a liquid crystal composition is used, the ambient temperature at which the liquid crystal display device using it as a constituent material is naturally limited. As is clear from the above, it is a highly reliable liquid crystal composition in which crystals do not precipitate even at a lower temperature and sufficiently satisfies the electro-optical characteristics required for various display systems and drive systems. Despite the desire for liquid crystal compositions, such liquid crystal compositions have not yet been obtained.

[0031]

The problem to be solved by the present invention is to show the effect that the problem of crystal precipitation in a low temperature region can be remarkably improved by adding it to a liquid crystal material, and the threshold voltage etc. Another object of the present invention is to provide a liquid crystal material which does not deteriorate the electro-optical characteristics of the above.

[0032]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve the above problems. However, there is a limit to the improvement of the characteristics as described above only with the liquid crystal compounds which are currently widely used. . Therefore, the present inventors considered that it is necessary to develop a liquid crystal material that has not been used in general-purpose liquid crystal compositions at all.

Therefore, the present inventors have paid attention to various documents, and among them, regarding the liquid crystal compound having a deuterium atom (D), there have already been some reports as shown below. 1) H. Gasparoux et al., Ann.ReV.Phys.Chem., 27, 175 (1976) 2) GWGray et al., Mol.Cryst.Liq.Cryst., 41, 75 (1977) 3) AJ Leadbetter et al., J. Phys . [Paris] coll C3, 40,
125 (1979) 4) A. Kolbe et al., Z. Naturforsch., 23a, 1237 (1968) 5) JD Rowell et al., J. Chem. Phys., 43, 3442 (1965) 6) WD Philips et al., J. Chem. Phys ., 41, 2551 (1964) 7) AF Martins et al., Mol.Cryst.Liq.Cryst., 14, 85 (197
1) 8) ET Samulski et al., Phys. Rev. Lett., 29, 340 (1972) 9) H. Zimmermann et al., Liquid Crystals., 4, 591 (1989)

However, in these reports, 4
-Example of replacing hydrogen atom (H) in carboxyl group of alkoxyalkoxybenzoic acid with deuterium atom (D) (Reference (1))
In all the examples except the above, the hydrogen atom (H) in the terminal group was replaced with a deuterium atom (D), or the hydrogen atom (H) bonded to the benzene ring was replaced with a deuterium atom (D). . Moreover, these documents do not describe even an example in which the compound is added to a liquid crystal composition.

Therefore, the present inventors have not reported a hydrogen atom (H) bonded to a saturated hydrocarbon ring, which has not been reported so far.
Was attempted to be replaced by a deuterium atom (D), but it was revealed that the liquid crystal material obtained thereby had excellent properties that could not be predicted at all from the aforementioned literature. . That is, the present invention has the general formula (I) in order to solve the above problems.

[0036]

[Chemical 9]

(In the formula, R¹Is an alkane having 1 to 12 carbon atoms
Represents a kill group, X¹, X², X³And X ^FourAre independent
Represents a hydrogen atom (H) or a deuterium atom (D),
At least one represents a deuterium atom (D), and Y¹as well as
Y²Each independently represent a hydrogen atom or a fluorine atom.
Z is a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group,
-R², -OR², -OCN, -CF₃, -OCF₃, -O
CF₂H or -OCH₂CF ₃And R²Is the number of carbon atoms
Alkyl group having 1 to 12 or alkene having 2 to 12 carbon atoms
Represents a nyl group, and the cyclohexane ring is in the trans configuration.
It ) Two or more compounds represented by
X¹~ X^FourNumber and / or substitution of deuterium atoms (D) in
The position is different, and (2) R is mutually¹, Y¹, Y²And Z
Are represented by the above general formula (I),
A mixture of two or more compounds (hereinafter, generally referred to as
A mixture of formula (I)).

Among them, in the general formula (I), Z is a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a linear alkyl group having 1 to 7 carbon atoms or an alkoxyl group,
Preferably it represents OCF ₃ or —OCH ₂ CF ₃ ,
Especially fluorine atom, a cyano group, or -OCF ₃ preferred.

Further, it is preferable that at least two of (A) Y ¹ , Y ² and Z represent a fluorine atom. Among them, Y ¹ and Z both represent a fluorine atom and Y ² represents a hydrogen atom. Mixtures or mixtures in which Y ¹ , Y ² and Z all represent fluorine atoms are preferred. Alternatively, (B) it is preferable that both Y ¹ and Y ² represent a hydrogen atom, and a mixture in which Z represents a cyano group or —OCF ₃ is particularly preferable. Further, as described above, in the mixture of the general formula (I), R ¹ preferably represents a linear alkyl group having 1 to 7 carbon atoms.

As described above, the feature of the mixture of the general formula (I) is that in the general formula (I), X ¹ , X ² , X ³ and X ⁴ are each independently a hydrogen atom (H) or a heavy atom. A compound which represents a hydrogen atom (D) and at least one of which is a deuterium atom (D) is composed of two or more compounds, and in the two or more compounds, (1) X ^{1 to} X ⁴ are mutually present.
The number and / or substitution position of deuterium atoms (D) in the above are different, and (2) R ¹ , Y ¹ , Y ² and Z are mutually the same. That is, when R ¹ , Y ¹ , Y ² and Z are fixed in the general formula (I), the compound of the general formula (I) may include about 10 kinds of compounds including stereoisomers. become.

However, as will be described later, it is not industrially advantageous to selectively produce each of these 10 compounds in the production process, because the production process becomes complicated. Therefore, there is no problem as a liquid crystal material when it is used as a liquid crystal material in the form of a mixture consisting of several kinds of compounds of 10 kinds of homologues depending on the number of deuterium atoms (D) and / or the difference in the substitution position.

On the contrary, when it is used as a mixture, excellent properties such that crystal precipitation in the low temperature region is hard to occur and compatibility with other liquid crystal compounds is improved are obtained, rather, it is represented by the general formula (I). Is more preferable than the case where one compound is used alone. Further, among such mixtures of the present invention, the ratio of the number of deuterium atoms (D) in the mixture composed of two or more compounds represented by the general formula (I) is from X ¹ to general formula (I). 3 for X ⁴
Mixtures in the range 0 to 95% are preferred, 40 to 90
% Is more preferable, and 60 to 90% is particularly preferable. The mixture of the general formula (I) according to the present invention has, for example, the general formula (II)

[0043]

[Chemical 10]

(Where R is¹Is an alkane having 1 to 12 carbon atoms
Represents a kill group, X¹, X², X³And X ^FourAre independent
Represents a hydrogen atom (H) or a deuterium atom (D),
At least one represents a deuterium atom (D),
The xane ring is in the trans configuration. ) 2 types or more
The above compounds are (1) X¹~ X^FourDeuterium in Japan
The number of children (D) and / or the substitution position is different, and (2)
R to each other¹Are the same, said general formula
Mixture of two or more compounds represented by (II)
Other than using (hereinafter referred to as a mixture of general formula (II))
Is not deuterium substituted

[0045]

[Chemical 11]

(Wherein R ¹ , Y ¹ , Y ² and Z have the same meanings as in formula (I)) and can be produced in the same manner as in the production of the compound represented by the formula (I). The invention also provides a mixture of general formula (II).

[0047]

[Chemical 12]

(In the formula, R ¹ , X ¹ , X ² , X ³ and X ⁴ have the same meanings as in formula (I).)
In the mixture of the general formula (II), two or more compounds represented by the general formula (IV) are (1) different from each other in the number of deuterium atoms (D) in X ^{1 to} X ⁴ and / or the substitution position, And (2) a mixture of two or more compounds represented by the general formula (IV), wherein R ^{1 s} are the same, (hereinafter referred to as a mixture of the general formula (IV)),
The enol ether obtained is reacted with a Wittig reagent of the formula (Va) and treated with an acid. The mixture obtained here is a mixture of isomers in which the configuration of the cyclohexane ring is cis, trans and trans, trans. Next, by isomerizing this into trans, trans with a base,
A mixture of general formula (II) according to the invention can be obtained.

As described above, in the mixture of the general formula (I) of the present invention, in two or more compounds represented by the general formula (I), the deuterium atom (D) with respect to the total number of X ^{1 to} X ⁴ is added. A mixture in which the ratio of the number of is in the range of 30 to 95% is preferable because it can exhibit a more excellent effect, but in each mixture of the general formula (II) or (III), In two or more compounds represented by each general formula, the ratio of the number of deuterium atoms (D) to the total number of X ^{1 to} X ⁴ is preferably in the range of 30 to 95%, and 40 to 90%. The range is more preferable, and 60 to
A range of 90% is particularly preferred. Here, the general formula (II)
The mixture of can be produced as follows.

[0050]

[Chemical 13]

(In the formula, R ¹ , X ¹ , X ² , X ³ and X ⁴ have the same meanings as in formula (I), and R ³ represents a hydrogen atom or an alkyl group having 1 to 11 carbon atoms. Represent, R ³
CH ₂ and R ¹ represent the same group. ) By dissolving the monoethylene acetal of bicyclohexane-4,4'-dione of the general formula (VI ') in an aprotic solvent such as dichloromethane and reacting it with heavy water in the presence of a base such as alcoholate, the cyclohexanone ring Two
A mixture of two or more kinds of monoethylene acetal of general formula (VI) bicyclohexane-4,4′-dione substituted with deuterium at the 6- and 6-positions (hereinafter referred to as the mixture of general formula (VI)) Obtainable. At this time, the reaction is preferably carried out at room temperature to the reflux temperature of the solvent, and in order to promote the reaction, it is also preferable to coexist with a quaternary ammonium salt such as tetrabutylammonium bromide. This general formula (V
The mixture of I) is reacted with a Wittig reagent of the general formula (Vb), the resulting alkylidenecyclohexane derivative is hydrogenated, the cyclohexane ring having a cis configuration is separated and removed, and then deacetalized with an acid. Due to
A mixture of general formula (IV) can be obtained.

[0052]

[Chemical 14]

(In the formula, R ¹ , X ¹ , X ² , X ³ and X ⁴ have the same meanings as in the general formula (I).) Alternatively, instead of the Wittig reagent of the general formula (Vb), The cyclohexanol derivative is obtained by reacting a mixture of the general formula (VI) with an alkyl Grignard reagent (R ¹ MgBr) or the like, and dehydrating the obtained cyclohexanol derivative. This is hydrogenated to remove the cyclohexane derivative having a cis configuration by separation to give a compound of the general formula (IV)
It is also possible to obtain a mixture of However, in this case, in the obtained mixture of general formula (IV), at least one of X ^{1 to} X ⁴ is a hydrogen atom (H), and for convenience, X ⁴ may be regarded as a hydrogen atom (H). The mixture of the general formula (IV) thus obtained is converted into the compound of the formula (V
By reacting with the Wittig reagent of a), a mixture of general formula (II) can be obtained.

[0054]

[Chemical 15]

(In the formula, R ¹ , X ¹ , X ² , X ³ and X ⁴ have the same meanings as in the general formula (I).) Now, the mixture of the general formula (II) obtained here is Of the deuterium-substituted trans-4′-alkylbicyclohexane-trans-4-ethanal represented by the general formula (III) by reacting again with the Wittig reagent of the formula (Va) and then hydrolyzing. (1) Deuterium atom (D) at X ^{1 to} X ⁴
Different in the number and / or substitution position, and (2) are mutually R
Wherein the ¹ is the same, the above general formula (II
A mixture of two or more compounds represented by I) (hereinafter referred to as a mixture of general formula (III)) can be obtained. The invention also provides this mixture of general formula (III). When the mixture of the general formula (I) is produced by using the mixture of the general formula (III) as an intermediate, its Y ¹ , Y ² and Z
According to the above, for example, it can be manufactured as follows.

A) In the general formula (I), Z = H, F,
R ^2, -OR ^2, when the mixture is -CF ₃ or -OCF ₃

[0057]

[Chemical 16]

(In the formulae, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) When Z is the above group, Grignard Since it is inactive with respect to the reactant, the 4-bromo derivative of the general formula (VII) is directly reacted with magnesium as a Grignard reactant with the mixture of the general formula (III) to dehydrate the obtained benzyl alcohol derivative. To obtain a styrene derivative, followed by hydrogenation.

B) In the general formula (I), Z = -O
For R ^2, the mixture is -OCH ₂ CF ₃

[0060]

[Chemical 17]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in the general formula (I).) In the above general formula (VII) ), Z =-
In the same manner as in (a) except that a 4-bromo derivative of OCH ₃ is used, Z = -OCH in the general formula (I).
A mixture that is ₃ can be obtained. This is demethylated (trimethylsilyl iodide, boron tribromide, aluminum chloride, hydrobromic acid, etc. can be used),
A mixture of phenolic derivatives of general formula (Ioh) is obtained. In the presence of a base, R
(Wherein, W is a bromine atom, a leaving group such as iodine or p- toluenesulfonyl group.) ² W or WCH ₂ CF ₃ by reaction with, in formula (I), Z is -OR it is possible to obtain a ^two or a mixture is -OCH ₂ CF _3. Alternatively, this general formula (Ioh)
The mixture of the phenol derivatives of
It can also be obtained by reacting a mixture of the aniline derivative of h) with sodium nitrite in an aqueous sulfuric acid solution to form a diazonium salt, and decomposing this.

C) In the general formula (I), Z = -OCF
_For a mixture that is ₂ H

[0063]

[Chemical 18]

(In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in the general formula (I).) The general formula obtained in the above b) The mixture of (Ioh) is used as a formic acid ester, and this is fluorinated with dimethylaminosulfur trifluoride (DAST) or the like, whereby a mixture of Z = -OCF ₂ H in the general formula (I) can be obtained. .

D) In the case of a mixture of the general formula (I) in which Z = -CN

[0066]

[Chemical 19]

(In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) In the above a), Z is a hydrogen atom. Is a general formula (Ih)
Is reacted with oxalic acid chloride in the presence of Lewis acid to give a mixture of acid chlorides of general formula (Ich) and then with ammonia to give a mixture of amides of general formula (Iam). By dehydrating this with thionyl chloride or the like, a mixture of Z = -CN in the general formula (I) can be obtained.

[0068]

[Chemical 20]

(In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) Ich) mixture is
It may also be obtained by acetylating a mixture of the general formula (Ih), oxidizing it with bromine in an aqueous alkali solution to give a mixture of carboxylic acids of the general formula (Ica), and then reacting it with a chlorinating agent such as thionyl chloride. it can.

[0070]

[Chemical 21]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) Alternatively, a mixture of formula (Ih) It is also possible to obtain a mixture of Z = -CN in the general formula (I) by directly iodizing the compound with iodine / periodic acid and then reacting it with copper (I) cyanide.

E) In the case of a mixture of the general formula (I) in which Z = Cl

[0073]

[Chemical formula 22]

(In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) When the activity of chlorine is low, It can also be obtained in the same manner as in (a) above. However, more generally, by reacting a mixture of amides of general formula (Iam) with bromine in an aqueous alkaline solution, a mixture of aniline derivatives of general formula (Inh) is obtained, which is reacted in the presence of hydrochloric acid. By reacting with sodium nitrate to form a diazonium salt, which is further decomposed with copper (I) chloride, a mixture of Z = Cl in the general formula (I) can be obtained.

F) In the general formula (I), Z = -OCN
For a mixture that is

[0076]

[Chemical formula 23]

(In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) Of the phenol derivative of formula (Ioh) By reacting the mixture with cyanogen bromide in the presence of a basic substance such as triethylamine, in the general formula (I), Z = -OC
A mixture of N can be obtained.

[0078]

[Chemical formula 24]

(In the formula, R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ and Y ² have the same meanings as in formula (I).) In each of the above production steps, Y ¹ When at least one of Y and Y ² is a fluorine atom, it may be difficult to obtain the corresponding compound of the general formula (VII) in the above step (a), for example. Alternatively, in the step (d), it may be difficult to selectively introduce the substituent Z into a desired position. In such a case, the mixture of the general formula (Ih) is lithiated with butyllithium or the like to give a mixture of phenyllithium derivatives of the general formula (Ii), which is directly alkylated (in the general formula (I), Z = R ² ) or by reacting with carbon dioxide to give a compound of the general formula (Ica)
It is possible to obtain the derivative of the carboxylic acid of and obtain it from the above-mentioned method.

Examples of the mixture of the general formula (I) thus obtained are listed in Table 1 together with their phase transition temperatures.

[0081]

[Table 1]

(In the table, C represents a crystalline phase, Sm represents a smectic phase, N represents a nematic phase, and I represents an isotropic liquid phase. In addition, No. 1 and No. 3 do not crystallize. Its melting point was unknown, and the D conversion rate was deuterium atom (D) with respect to the total number of X ^{1 to} X ⁴ in the mixture.
It shows the ratio of the number of. )

The mixture of the general formula (I) of the present invention, which is not deuterium-substituted, has an excellent feature that it does not precipitate crystals even in a low temperature region as compared with a single compound having the same skeleton.

As such an example, it is currently widely used.

[0085]

[Chemical 25]

(Wherein, the cyclohexane ring represents the trans configuration and "%" represents "% by weight"), and 80% by weight of the base liquid crystal (A) and (No. 1) in Table 1.

[0087]

[Chemical formula 26]

(In the formula, “d ₄ −” is a mixture of compounds of the general formula (I) in which at least one of the substituents X ^{1 to} X ⁴ is a deuterium atom (D). A mixed liquid crystal (M-
When 1) was prepared, it showed a nematic phase at 65.4 ° C or lower. When this composition was stored at -20 ° C, 2
No precipitation of crystals could be observed even after a week.

On the contrary, it has a similar structure of a mixture of the same host liquid crystal (A) (80% by weight) and (No. 1),
Formula (R-1) not substituted with deuterium

[0090]

[Chemical 27]

A mixed liquid crystal (M
When R-1) was prepared and stored at -20 ° C in the same manner, precipitation of crystals was observed after 5 days. Next, especially suitable for active matrix

[0092]

[Chemical 28]

(In the formula, the cyclohexane ring represents the trans configuration and "%" represents "% by weight") to prepare a base liquid crystal (B). This host liquid crystal (B) has 11
It shows a nematic phase below 6.7 ℃ and its melting point is 11 ℃.
Is.

70% by weight of this base liquid crystal (B) and (No. 2) in Table 1

[0095]

[Chemical 29]

[0096] (wherein, "d ₄ -". Is that the same meanings as described above) mixed crystal consisting of a mixture 30% by weight of (N-
When 2) was prepared and stored at 0 ° C., precipitation of crystals could not be observed even after 2 weeks.

On the other hand, it has a similar structure of a mixture of 70% by weight of the same base liquid crystal (B) and (No. 2),
Formula (R-2) not substituted by deuterium

[0098]

[Chemical 30]

A mixed liquid crystal (N
R-2) was prepared and similarly stored at 0 ° C.,
After 1 day, it was completely crystallized and its melting point was measured and found to be 6 ° C.

From the above, the mixture of the deuterium-substituted compounds of the general formula (I) according to the present invention has an excellent feature that it is difficult to deposit crystals in the mixed liquid crystal even in a low temperature region. Obviously, it is extremely useful as a constituent material of a liquid crystal display device expected to be used in a low temperature region.

[0101]

EXAMPLES The present invention will be further described below by showing Examples of the present invention. However, the invention is not limited to these examples.

The structure of the compound has the same retention time (or Rf value) when a known compound not deuterated is compared with a capillary gas chromatograph and a thin layer chromatograph, and a nuclear magnetic resonance spectrum ( NM
R), mass spectrum (MS), infrared absorption spectrum (IR).

The D conversion rate of the mixture as a whole was measured by NMR, and the measurement was conducted according to "JNM-GSX40".
0 "(manufactured by JEOL Ltd., 400 MHz ¹ H) was used.

The D conversion rate of the mixture in the general formula (I), the general formula (II) and the general formula (III) was regarded as the same as the D conversion rate of the mixture in the general formula (IV) as an intermediate. . I wrote in front of the compound name and structural formula "d ₄ -"
Is a compound of the formula (I), (II), (III), (IV) or (VI) in which at least one of the substituents X ^{1 to} X ⁴ is a deuterium atom (D). Is a mixture of

Reference Example 1 Bicyclohexane-4,
Deuteration of 4'-dione monoethylene acetal

[0106]

[Chemical 31]

54.0 g of sodium methoxide was dissolved in 100 ml of heavy water (D conversion rate: 99.8%). Bicyclohexane-4,4'-dione monoethylene acetal 100.2 dissolved in 100 ml of dichloromethane was added thereto.
g, and then tetrabutylammonium bromide 2.0 g
Was added, and the mixture was heated with stirring at the reflux temperature of the solvent for 10 hours. After cooling, the organic layer was separated, and the reaction product of the aqueous layer was extracted with dichloromethane and then collected. The organic layer was combined with this, washed with water, and dehydrated and dried over anhydrous sodium sulfate.

The solvent was distilled off and d ₄ -bicyclohexane-4,4'-dione monoethylene acetal 100.5 was added.
g was obtained. When the D conversion rate was measured by NMR,
It was about 86%.

Reference Example 2 d ₄ -4- (transformer-4)
-Propylcyclohexyl) cyclohexanone

[0110]

[Chemical 32]

46.4 g of propyltriphenylphosphonium iodide was suspended in 150 ml of toluene and 46 ml of THF and cooled to 0 ° C. with ice. t-Butoxy potassium 1
3.0 g was added and stirred for 1 hour to prepare a Wittig reaction agent. This obtained in Reference Example 1 and d ₄ - bicyclohexane-4,4'-dione monoethylene acetal 2
A 40 ml solution of 0.0 g of toluene was added dropwise at an internal temperature of 10 ° C. or lower, and the mixture was further stirred at the same temperature for 1 hour. After adding 200 ml of water and neutralizing with dilute hydrochloric acid, the organic layer was separated and concentrated under reduced pressure. The obtained residue was dissolved in 200 ml of hexane and the insoluble material was filtered off. The filtrate was washed with a water / methanol mixed solvent and the solvent was distilled off to obtain 37.4 g of a crude product.
Silica gel column chromatography (hexane / ethyl acetate = 5/1) as eluant to give the d _{4-4'-propylidene} bicyclohexane-4-one monoethylene acetal 20.52 g.

All of this was dissolved in 300 ml of toluene,
21 ml of triethylamine and 4.0 g of palladium on carbon
Was added, and the mixture was stirred in an autoclave at a hydrogen pressure of 5 Kg / cm ² at room temperature. After the catalyst was filtered off, it was washed with dilute hydrochloric acid and then with water. 350 ml of formic acid was added, and the mixture was stirred at 80 ° C for 1 hour. The reaction solution was poured into water, the reaction product of the aqueous layer was extracted with toluene, the organic layer was combined with this, and washed with a saturated sodium hydrogen carbonate aqueous solution, water, and a saturated saline solution. After dehydration drying with anhydrous sodium sulfate, the solvent was distilled off to obtain a d _4-4- (trans-4-propyl) cyclohexanone and d ₄ 4- (cis-4-propyl-cyclohexyl) mixture of cyclohexanone. This is subjected to silica gel column chromatography (hexane / ethyl acetate =
And purified using 9/1), d ₄ -4- (trans-4
-Propylcyclohexyl) cyclohexanone 16.1
1 g was obtained. It was recrystallized from hexane and its melting point was measured and found to be 25 to 26 ° C.

Example 1 Synthesis of d ₄ -trans-4′-propylbicyclohexane-4-carbaldehyde

[0114]

[Chemical 33]

32.5 g of methoxymethyltriphenylphosphonium chloride was suspended in 100 ml of THF. This was ice-cooled, 10.8 g of potassium t-butoxide was slowly added, and the mixture was stirred at 0 ° C for 1 hr. D obtained in Reference Example 2
_4-4 was dissolved (trans-4-propyl-cyclohexyl) cyclohexanone 15g to THF85ml, was added dropwise over 30 minutes at the same temperature. After stirring for another 30 minutes, water 1
00 ml was added. The aqueous layer was separated, the organic layer was concentrated, 100 ml of hexane was added, and the insoluble material was filtered off. The precipitate was washed with hexane. The filtrate was collected, washed with a mixed solvent of methanol / water and then concentrated. The obtained oily crude product was dissolved in 100 ml of THF, and 100% of 10% hydrochloric acid was added.
ml was added and the mixture was heated with stirring for 1 hour. After cooling, the reaction product was extracted with 100 ml of ethyl acetate, washed with water, and the solvent was distilled off. 120 ml of the obtained oil is ethanol.
The resulting mixture was dissolved in water, 12 ml of 20% aqueous sodium hydroxide solution was added, and the mixture was stirred for 2 hours. 150 ml of water was added, and the deposited precipitate was filtered. The precipitate was washed with 150 ml of water and then with 150 ml of methanol, and dried under reduced pressure to obtain 14.9 g of white crystals of d ₄ -trans-4′-propylbicyclohexane-4-carbaldehyde.

Example 2 Synthesis of d ₄ -trans-4′-propylbicyclohexane-4-ethanal

[0117]

[Chemical 34]

29 g of methoxymethyltriphenylphosphonium chloride was suspended in 90 ml of THF and cooled with ice.
9.6 g of potassium t-butoxide was slowly added, and the mixture was stirred for 1 hour. D ₄ -trans-4 ′ obtained in Example 1
-Propylbicyclohexane-4-carbaldehyde 1
4.8 g was dissolved in 85 ml of THF and added dropwise at the same temperature for 30 minutes. After stirring for another 30 minutes, 130 ml of water was added. The organic layer was concentrated, 100 ml of hexane was added to dissolve it, the insoluble matter was filtered off, and then washed with 100 ml of a mixed solvent of methanol / water = 1/1. The hexane layer was concentrated, and the obtained oily crude product was dissolved in 100 ml of THF,
100 ml of 0% hydrochloric acid was added, and the mixture was heated with stirring under reflux of the solvent for 1 hour. After standing to cool, the reaction product was diluted with 100 ml of ethyl acetate.
After extraction, washing with water, dehydration drying over anhydrous sodium sulfate, evaporation of the solvent, and white crystals of d ₄ -trans-4′-propylbicyclohexane-4-ethanal 1
1.8 g was obtained.

(Example 3) d ₄ -trans-4- [2
-(3,4-Difluorophenyl) ethyl] -trans-4'-propylbicyclohexane (No.
1 mixture)

[0120]

[Chemical 35]

(3-a) Synthesis of d ₄ -trans-4′-propyl-trans-4- [2- (3,4-difluorophenyl) ethenyl] bicyclohexane 560 g of shaving magnesium in 2 ml of dry THF.
1 g of 1-bromo-3,4, -difluorobenzene 3.
A solution of 70 g of THF in 20 ml was added dropwise at such a rate that a gentle reflux was maintained. After the completion of dropping, the mixture was stirred for 1 hour and then left to cool. Under ice-cooling, obtained in Example 2 d ₄ - Be careful temperature inside the THF20ml solution of trans-4'-propyl-bi cyclohexane-4-ethanal 4.00g does not to exceed a 40 ° C. added dropwise in 1 hour did. After stirring at room temperature for another hour, dilute hydrochloric acid was added with stirring until the aqueous layer became weakly acidic. The reaction product was extracted with 40 ml of ethyl acetate, the organic layer was washed with water and then with saturated saline, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, the obtained oily substance was dissolved in 30 ml of toluene, 160 mg of p-toluenesulfonic acid monohydrate was added, and the mixture was heated with stirring under reflux for 6 hours. After cooling, it was washed with a saturated aqueous solution of sodium hydrogencarbonate and then with water, and dried over anhydrous sodium sulfate. The crude product obtained by distilling off the solvent is purified using silica gel column chromatography (hexane),
d ₄ - trans-4'-propyl - trans-4- [2
4.40 g of-(3,4-difluorophenyl) ethenyl] bicyclohexane was obtained.

(3-b) d ₄ -trans-4- [2-
(3,4-Difluorophenyl) ethyl] -trans-
Synthesis of 4′-propylbicyclohexane The total amount of d ₄ -trans-4′-propyl-trans-4- [2- (3,4-difluorophenyl) ethenyl] bicyclohexane obtained in (3-a) above was used. It was dissolved in 30 ml of ethyl acetate. 0.44 g of palladium carbon was added thereto, and the mixture was stirred under a hydrogen atmosphere at room temperature and atmospheric pressure for 6 hours.
The catalyst was removed by celite filtration, and the solvent was distilled off under reduced pressure, d ₄ - trans-4- [2- (3,4-difluorophenyl) ethyl] - trans-4'-propyl-bi cyclohexane 4.40g Got This is purified by silica gel column chromatography (hexane) and further recrystallized from a mixed solvent of ethanol / hexane (9/1) to give 3.55 g of a purified product showing a smectic phase at room temperature.
Got The D conversion rate of this mixture is shown in Table 1. Phase transition temperature (° C.): 47 (Sm → N), 117 (NI)

(Comparative Example 1) Trans-4- [2-
(3,4-Difluorophenyl) ethyl] -trans-
Synthesis Example 1 4'-propyl-bi cyclohexane (a compound of the formula (R-1)), instead of d ₄ 4- (trans-4-propyl-cyclohexyl) cyclohexanone, not deuterated 4- ( Example 1 except that trans-4-propylcyclohexyl) cyclohexanone was used.
Deuterium-substituted trans-4- [2- (3,4-difluorophenyl) ethyl] -trans-4′-propylbicyclohexane was obtained in the same manner as 2 and 3. The phase transition temperature of this compound was as follows. Phase transition temperature (° C): 19 (Cr → Sm), 50 (Sm-
N), 118.5 (N-I)

Example 4 d ₄ -trans-4- [2
Synthesis of-(3,4,5-trifluorophenyl) ethyl] -trans-4'-propylbicyclohexane (mixture of No. 2 in Table 1) In Example 3, 1-bromo-3,4- D ₄ was performed in the same manner as in Example 3 except that 1-bromo-3,4,5-trifluorobenzene was used instead of difluorobenzene.
-Trans-4- [2- (3,4,5-trifluorophenyl) ethyl] -trans-4'-propylbicyclohexane was obtained. The phase transition temperature and the D conversion rate are summarized in Table 1.

Example 5 d ₄ -trans-4- [2
Synthesis of-(4-trifluoromethoxyphenyl) ethyl] -trans-4'-propylbicyclohexane (mixture of No. 3 in Table 1) In Example 3, 1-bromo-3,4-difluorobenzene was added. Instead, d ₄ was obtained in the same manner as in Example 3 except that 1-bromo-4-trifluoromethoxybenzene was used.
-Trans-4- [2- (4-trifluoromethoxyphenyl) ethyl] -trans-4'-propylbicyclohexane was obtained. The phase transition temperature and the D conversion rate are summarized in Table 1.

Example 6 d ₄ -trans-4- [2
-(4-Cyanophenyl) ethyl] -trans-4'-
Synthesis of propylbicyclohexane (mixture of No. 4 in Table 1)

[0127]

[Chemical 36]

(6-a) d ₄ -trans-4- (2-
Synthesis of phenylethyl) -trans-4′-propylbicyclohexane In the same manner as in Example 3 except that bromobenzene was used instead of 1-bromo-3,4-difluorobenzene, d ₄ -Trans-4- (2-phenylethyl) -trans-4'-propylbicyclohexane was obtained.

(6-b) d ₄ -trans-4- [2-
(4-cyanophenyl) ethyl] - d ₄ was obtained above trans-4'-propyl-bi cyclohexane (6-a) - trans-4- (2-phenylethyl) - trans-4'-propyl bicyclohexane 5.30 g was dissolved in 45 ml of dichloromethane, and 4.42 g of anhydrous aluminum chloride was added and stirred. Under ice cooling, 2.22 g of oxalic acid dichloride was added dropwise over 30 minutes. After stirring at the same temperature for 1 hour, the temperature was returned to room temperature, the reaction solution was poured into ice water, and the reaction product was extracted with hexane,
The extract was concentrated, d ₄ -4- [2- [trans-4-
(Trans-4-propylcyclohexyl) cyclohexyl] ethyl] benzoic acid chloride was obtained. Dissolve the whole amount in 50 ml of dichloromethane and add 2% of 30% ammonia water.
0 ml was added and stirred for 1 hour. Hexane was added, and the precipitated crystals were collected by filtration, washed with dilute hydrochloric acid, saturated aqueous sodium hydrogen carbonate solution, water and cold methanol, and dried under reduced pressure.
crystals were obtained 4.4g of d ₄ -4- [2- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] ethyl] benzamide. Thionyl chloride 4
It was heated to reflux in 0 ml for 3 hours. Excess thionyl chloride was distilled off under reduced pressure, toluene was added, and the mixture was washed with saturated aqueous sodium hydrogen carbonate solution, water, and saturated brine, and dried over anhydrous sodium sulfate. The solvent was distilled off, and the obtained crude product was recrystallized from ethanol to obtain 3.5 g of d ₄ -trans-4- [2- (4-cyanophenyl) ethyl] -trans-4′-propylbicyclohexane. Obtained.
The phase transition temperature and the D conversion rate are summarized in Table 1.

Example 7 Preparation of Liquid Crystal Composition (1)

[0131]

[Chemical 37]

(Wherein the cyclohexane ring represents the trans configuration and "%" represents "% by weight"), a matrix liquid crystal (A) was prepared, and a nematic (N) phase was obtained at 54.5 ° C or lower. showed that.

A mixed liquid crystal (M-1) comprising 80% by weight of the base liquid crystal (A) and 20% by weight of the mixture of (No. 1) obtained in Example 3 was prepared. The maximum temperature of the N phase of this mixed liquid crystal was 65.4 ° C. This mixed liquid crystal is -20
When stored at 0 ° C., no crystal precipitation could be observed even after 2 weeks.

COMPARATIVE EXAMPLE 2 80% by weight of the base liquid crystal (A) and the formula (R-1) obtained in Comparative Example 1 which has a similar structure to (No. 1) but is not deuterium substituted.

[0135]

[Chemical 38]

A mixed liquid crystal (M
R-1) was prepared. The maximum temperature of the N phase of this mixed liquid crystal was 65.6 ° C. Next, when this mixed liquid crystal was stored at -20 ° C, precipitation of crystals was observed after 5 days.

From this, according to the present invention (No.
Although the mixture of 1) has a similar structure, the upper limit temperature of the N phase is almost the same as that of the compound which is not deuterium-substituted, and it is remarkably excellent in that crystals are not precipitated in the low temperature region. It is clear.

(Example 8) Preparation of liquid crystal composition (2) 80% by weight of the base liquid crystal (A) and the liquid crystal composition obtained in Example 4 (N) were used.
o. 2) Mixed liquid crystal (M-
2), a mixed liquid crystal (M-3) comprising 80% by weight of the base liquid crystal (A) and 20% by weight of the mixture of (No. 3) obtained in Example 5 was prepared. The upper limit temperature of the N phase of the mixed liquid crystal (M-2) is 60.5 ° C., and the (M-3) is 6
It was 8.8 ° C. When stored at -20 ° C in the same manner as in Example 7, no crystal precipitation could be observed even after 2 weeks.

Example 9 Preparation of Liquid Crystal Composition (3) Particularly Suitable for Active Matrix

[0140]

[Chemical Formula 39]

(In the formula, the cyclohexane ring represents a trans configuration, and “%” represents “% by weight”) to prepare a base liquid crystal (B). This host liquid crystal (B) has 11
It shows a nematic phase below 6.7 ℃ and its melting point is 11 ℃.
Met.

A mixed liquid crystal (N-1) comprising 70% by weight of the base liquid crystal (B) and 30% by weight of the mixture of (No. 1) of Example 3 was prepared, and the upper limit temperature of the N phase was 11
It was 5.7 ° C. When this mixed liquid crystal was stored at 0 ° C., no crystal precipitation was observed even after 2 weeks. Next, this mixed liquid crystal was stored at −40 ° C. and crystallized, and then the temperature was gradually raised to measure the melting point.
Met.

Comparative Example 3 A mixed liquid crystal (NR-1) comprising 70% by weight of the base liquid crystal (B) and 30% by weight of the compound of the formula (R-1) of Comparative Example 1 was prepared. The maximum temperature of the N phase of this mixed liquid crystal was 116 ° C. Next, when this mixed liquid crystal was stored at 0 ° C., it crystallized after 1 week.

Example 10 Preparation of Liquid Crystal Composition (4) 70% by Weight of Base Liquid Crystal (B) and (No. 2) of Example 4
A mixed liquid crystal (N-2) consisting of 30% by weight of the mixture of No. 3, 70% by weight of the base liquid crystal (B) and 30% by weight of the mixture of (No. 3) of Example 5 were prepared respectively. did. The maximum temperature of the N phase of the mixed liquid crystal (N-2) is 10
It was 9.0 degreeC and (N-3) was 120.5 degreeC.
When stored at 0 ° C. in the same manner, no precipitation of crystals was observed even after 2 weeks. After crystallization at −40 ° C. in the same manner as in Example 9, the melting point thereof was measured. As a result, the mixed liquid crystal (N-2) was 5 ° C. and (N-3) was about 0 ° C. Also fell below the melting point of the base liquid crystal (B).

(Comparative Example 4) Formula (R-2) having a similar structure of a mixture of 70% by weight of the base liquid crystal (B) and (No. 2) but not deuterium substituted.

[0146]

[Chemical 40]

A mixed liquid crystal (N
R-2) was prepared and similarly stored at 0 ° C.,
After 1 day, it was completely crystallized and its melting point was measured and found to be 6 ° C.

[0148]

INDUSTRIAL APPLICABILITY As shown in the examples, the mixture of the deuterium-substituted compounds represented by the general formula (I) of the present invention can be easily produced industrially from commercially available compounds. It is also possible to have excellent compatibility with other liquid crystal compounds. Therefore, when added to a liquid crystal material that is currently widely used, it has an excellent effect of not significantly lowering the T _NI point, lowering the electro-optical characteristics, and not precipitating crystals even in a low temperature region. To be Therefore, it is extremely useful as a constituent material of liquid crystal display devices used in a low temperature region, particularly TN, STN, and active matrix display devices.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display area C07C 43/225 C 7419-4H 47/105 47/34 255/50 261/02 9451-4H C09K 19/30 9279 -4H 19/52 9279-4H // G02F 1/13 500

Claims (22)

[Claims] 1. A compound represented by the general formula (I):(In the formula, R¹Represents an alkyl group having 1 to 12 carbon atoms
Then X¹, X², X³And X ^FourAre each independently a hydrogen atom
(H) or a deuterium atom (D), but at least 1
Represents a deuterium atom (D), Y¹And Y²Are each
Independently represents a hydrogen atom or a fluorine atom, and Z is a hydrogen atom.
Child, fluorine atom, chlorine atom, cyano group, -R², -O
R², -OCN, -CF₃, -OCF₃, -OCF₂H or
-OCH₂CF ₃And R²Has 1 to 12 carbon atoms
Represents an alkyl group or an alkenyl group having 2 to 12 carbon atoms
The cyclohexane ring is in the trans configuration. )
Two or more compounds to be given are (1) X¹~ X^FourTo
The number and / or substitution position of deuterium atoms (D) in the
And (2) R¹, Y¹, Y²And Z are the same
A compound represented by the general formula (I), characterized in that
A mixture of two or more compounds. 2. In the general formula (I), Z is a hydrogen atom,
Fluorine atom, a chlorine atom, a cyano group, a linear alkyl group or alkoxyl group having a carbon number of 1 to 7, -OCF ₃
Or claim 1, characterized in that represent -OCH ₂ CF ₃
The mixture described. 3. The mixture according to claim 2, wherein Z in the general formula (I) represents a fluorine atom, a cyano group or —OCF ₃ . 4. In the general formula (I), Y ¹ , Y ² and Z
4. The mixture according to claim 3, wherein at least two of them represent fluorine atoms. 5. The mixture according to claim 4, wherein in the general formula (I), Y ¹ and Z both represent a fluorine atom and Y ² represents a hydrogen atom. 6. In the general formula (I), Y ¹ , Y ² and Z
5. All represent fluorine atoms.
The mixture described. 7. The mixture according to claim 3, wherein Y ¹ and Y ² in the general formula (I) both represent a hydrogen atom. 8. The mixture according to claim 7, wherein Z in the general formula (I) represents a cyano group or —OCF ₃ . 9. The mixture according to claim 5, 6 or 8, wherein R ¹ in the general formula (I) represents a linear alkyl group having 1 to 7 carbon atoms. 10. The total number of X ¹ , X ² , X ³ and X ⁴ in two or more compounds represented by general formula (I),
The mixture according to any one of claims 1 to 9, wherein the ratio of the number of deuterium atoms (D) is in the range of 30 to 95%. 11. The total number of X ¹ , X ² , X ³ and X ⁴ in two or more compounds represented by general formula (I),
The mixture according to any one of claims 1 to 9, wherein the ratio of the number of deuterium atoms (D) is in the range of 40 to 90%. 12. The total number of X ¹ , X ² , X ³ and X ⁴ in two or more compounds represented by formula (I),
10. The mixture according to claim 1, wherein the ratio of the number of deuterium atoms (D) is in the range of 60 to 90%. 13. A compound represented by the general formula (II):(In the formula, R¹Represents an alkyl group having 1 to 12 carbon atoms
Then X¹, X², X³And X ^FourAre each independently a hydrogen atom
(H) or a deuterium atom (D), but at least 1
Represents a deuterium atom (D), and the cyclohexane ring is
It is a lance arrangement. ) Two or more compounds represented by
But (1) X¹~ X^FourOf the deuterium atom (D) at
The number and / or the substitution position are different, and (2) R are mutually¹
In the general formula (II), characterized in that
Mixtures of two or more of the compounds represented. 14. The mixture according to claim 13, wherein R ¹ in the general formula (II) represents a linear alkyl group having 1 to 7 carbon atoms. 15. Two or more kinds represented by the general formula (II)
In the compound of ¹, X², X³And X^FourFor the total number of
And the ratio of the number of deuterium atoms (D) is in the range of 30 to 95%.
15. The mixture according to claim 13 or 14, characterized in that
Stuff. 16. Two or more kinds represented by the general formula (II)
In the compound of ¹, X², X³And X^FourFor the total number of
And the ratio of the number of deuterium atoms (D) is in the range of 40 to 90%.
15. The mixture according to claim 13 or 14, characterized in that
Stuff. 17. Two or more kinds represented by general formula (II)
In the compound of ¹, X², X³And X^FourFor the total number of
And the ratio of the number of deuterium atoms (D) is in the range of 60 to 90%.
15. The mixture according to claim 13 or 14, characterized in that
Stuff. 18. A compound represented by the general formula (III):(In the formula, R¹Represents an alkyl group having 1 to 12 carbon atoms
Then X¹, X², X³And X ^FourAre each independently a hydrogen atom
(H) or a deuterium atom (D), but at least 1
Represents a deuterium atom (D), and the cyclohexane ring is
It is a lance arrangement. ) Two or more compounds represented by
But (1) X¹~ X^FourOf the deuterium atom (D) at
The number and / or the substitution position are different, and (2) R are mutually¹
Are the same, the above general formula (III)
A mixture of two or more compounds represented by 19. The mixture according to claim 18, wherein in the general formula (III), R ¹ represents a linear alkyl group having 1 to 7 carbon atoms. 20. The ratio of the number of deuterium atoms (D) to the total number of X ¹ , X ² , X ³ and X ⁴ in two or more compounds represented by general formula (III) is 30 to 95. 20. Mixture according to claim 18 or 19, characterized in that it is in the range of%. 21. The ratio of the number of deuterium atoms (D) to the total number of X ¹ , X ² , X ³ and X ⁴ in two or more compounds represented by the general formula (III) is 40 to 90. 20. Mixture according to claim 18 or 19, characterized in that it is in the range of%. 22. The ratio of the number of deuterium atoms (D) to the total number of X ¹ , X ² , X ³ and X ⁴ in two or more compounds represented by the general formula (III) is 60 to 90. 20. Mixture according to claim 18 or 19, characterized in that it is in the range of%.