JPH0827038A - Cyclohexyltolan derivative - Google Patents

Abstract

PURPOSE:To obtain the subject derivative useful as a constituent material for a liquid crystal display device, especially for TN or STN, readily producible from easily obtainable compounds, having excellent compatibility with other liquid crystal compounds, not precipitating crystal even in a low-temperature range. CONSTITUTION:This derivative is a mixture comprising the compounds of formula I [R<1> is a 1-12C alkyl; (n) is 0 or 1; X<1>, X<2> and X<3> are each independently H or deuterium atom (D); Y<1>, Y<2>, Y<3> and Y<4> are each independently H or F; Y<5> is H, F or ethyl; Z is or F, Cl, H, cyano, R<2> (R<2> is a 1-12C alkyl, etc.), CF3, etc.], whichin (A) the number of Ds and/or the substitution position is different mutually in X<1> to X<3> and (B) R<1>, (n), Y<1> to Y<5> and Z are mutually the same. The mixture of formula I is obtained by reacting a mixture of two or more compounds of formula II (W is Br or I) and two or more compounds of formula II, in which (A) the number of Ds and/or the substitution position is different mutually in X<1> to X<3> and (C) R<1>, (n), Y<1>, Y<2> and W are mutually the same, with a phenylacetylene derivative of formula III in the presence of a Pd catalyst and a copper catalyst in a solvent.

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. It relates to a mixture of cyclohexyl tolan derivatives having excellent effects.

[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 systems are TN (twisted nematic), STN (super twisted nematic), DS (dynamic light scattering), GH (guest / host), and FLC (ferroelectric liquid crystal). ), Etc., and the multiplex drive has been generally used instead of the conventional static drive. Recently, the TFT (Thin Film Tr) has been replaced by such a simple matrix drive.
An active matrix drive using an anistor) 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, the liquid crystal composition 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 when the voltage holding ratio of the liquid crystal composition is low, a flicker phenomenon occurs in which the luminance of a 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.

Also, in the active matrix drive system, the display system is the same as the conventional TN display system, 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 a p-type liquid crystal compound), those having a relatively large Δε also similarly lower the voltage holding ratio. Is not suitable for active matrix driving.

[0011]

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(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.

[0013]

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[0014]

[Chemical 4]

(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, 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 to the above fluoro compounds. 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 liquid crystal composition for active matrix 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. Furthermore, since the STN display method is widely applied to general-purpose devices such as laptop computers in particular, the low threshold voltage of (2) is also an important required characteristic.

In order to lower 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.

[0020]

[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. .

[0022]

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(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)
It is prepared by a method of mixing liquid crystalline compounds.

As the p-type liquid crystal compound having a large elastic constant ratio K ₃₃ / K ₁₁ , for example, a compound of the following formula is used.

[0025]

[Chemical 6]

(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 often decreases. 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 a low voltage and S with high contrast.
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.

At the T _CN point of the liquid crystal composition, a mixed composition composed of individual liquid crystal simple substances often exhibits a supercooling phenomenon. Therefore, at the T _CN point, the liquid crystal composition is solidified with liquid nitrogen or the like. Crystallization is performed by cooling to a glass state at 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. In addition, as described above, it is required that a nematic phase is stably shown in a wide temperature range from -40 ° C to 110 ° C for in-vehicle use or aircraft use, but -55 ° C.
At present, no liquid crystal composition has been obtained in which crystals do not precipitate even when stored at low temperature. Therefore, even a liquid crystal composition that is actually widely used for in-vehicle use is, for example, -25 ° C.
When stored in, some crystals may precipitate in about one week.

From such an example, the T _{CN of the} liquid crystal composition is also
Even if the point is very low, it does not mean that the crystal does not precipitate at a higher temperature. Therefore, what satisfies the characteristics of (1) above is not that the T _CN point is low, but that the crystal does not grow even in the low temperature region. No precipitation is required for high reliability.

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 can improve the 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-mentioned 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 the composition is used 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.

[0037]

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.

[0038]

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 reports of several examples 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) JDRowell et al., J. Chem. Phys., 43, 3442 (1965) 6) WDPhilips et al., J. Chem. Phys. ., 41, 2551 (1964) 7) AFMartins 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, none of these documents describes 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.

[0043]

[Chemical 7]

(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, n represents 0 or 1, and X ¹ , X ² and X ³ are each independently a hydrogen atom (H) or a heavy atom. Represents a hydrogen atom (D), but at least one is a deuterium atom (D)
Y ¹ , Y ² , Y ³ and Y ⁴ each independently represent a hydrogen atom or a fluorine atom, Y ⁵ represents a hydrogen atom, a fluorine atom or a methyl group, and Z represents a fluorine atom, a chlorine atom or hydrogen. atom, a cyano ^{group, -R 2, -OR 2, -CF} 3,
Represents —OCF ₃ , —OCF ₂ H or —OCH ₂ CF ₃ ,
R ² represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 3 to 12 carbon atoms, and the cyclohexane ring has a trans configuration. Two or more compounds represented by the formula (1) are different from each other in the number and / or substitution position of the deuterium atoms (D) in X ^{1 to} X ³ , and (2) R ¹ , n, Y ¹ ; Y ² , Y ³ , Y ⁴ , Y ⁵ and Z are the same, a mixture of two or more compounds represented by the general formula (I) (hereinafter, a mixture of the general formula (I) And)).

[0045] Of this, in the general formula (I), Z is a fluorine atom, a chlorine atom, a cyano group, -R ^2, -OR ^2, -O
Preference is given to the mixtures of the general formula (I) which are characterized in that they represent CF ₃ and R ² represents an alkyl radical having 1 to 12 carbon atoms.

More specifically, in the general formula (I), n
Is preferably 0, and a mixture characterized in that Y ¹ and Y ² both represent a hydrogen atom, particularly in the general formula (I), Y ⁵ represents a hydrogen atom, Z represents a fluorine atom, a cyano group, R ^2, mixture, characterized in that represent -OR ^2, in the general formula (I), Y ⁵ represents a methyl group, Y ³ and Y ⁴ are both hydrogen, the Z represents -R ² A mixture characterized by: or general formula (I)
In the above, a mixture characterized in that Y ⁵ represents a fluorine atom, Y ³ represents a fluorine atom, Y ⁴ represents a hydrogen atom, and Z represents —OR ² is also preferable.

Apart from this, in the general formula (I), n
Represents 0, at least one of Y ¹ and Y ² represents a fluorine atom, Y ⁵ represents a hydrogen atom, and Z represents a fluorine atom, a chlorine atom, —R ² , or —OR ^2. A mixture of the above-mentioned general formula (I) is also preferable, among which, in the general formula (I), Y ³ and Y ⁴ both represent a hydrogen atom, and Z represents a fluorine atom, —R ² , or —OR ^2. A mixture characterized by the general formula (I) wherein Y
^At least one of ³ and Y ⁴ represents a fluorine atom,
Preference is given to mixtures characterized in that Z represents a fluorine atom or a chlorine atom.

In the formula (I), the mixture in which n is 1 is such that Y ¹ and Y ² both represent a hydrogen atom or a fluorine atom, and Y ³ and Y ⁴ both represent a hydrogen atom or a fluorine atom. , Y ⁵ represents a hydrogen atom, and Z represents a fluorine atom or —R ² .

As described above, the feature of the mixture of the general formula (I) is that in the general formula (I), X ¹ , X ² and X ³ are each independently a hydrogen atom (H) or a deuterium atom ( D) and at least one of which is a deuterium atom (D), and is composed of two or more compounds, and
In one or more compounds, (1) the number and / or substitution position of deuterium atoms (D) in X ^{1 to} X ³ are different from each other,
And (2) R ¹ , n, Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Z are the same as each other. That is, in the general formula (I), R ¹ , n, Y ¹ , Y ² , Y ³ , Y ⁴ ,
When Y ⁵ and Z are fixed, the compound of the general formula (I) may have about 10 or more kinds of compounds including stereoisomers.

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 does not occur easily 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.

Among such mixtures of the present invention, the ratio of the number of deuterium atoms (D) in the mixture of two or more compounds represented by the general formula (I) is the same as in the general formula (I). A mixture in the range of 30 to 95% with respect to X ^{1 to} X ³ is preferable, a range of 40 to 90% is more preferable, and a range of 60 to 90% is particularly preferable.

The mixture of general formula (I) according to the invention is
General formula (II)

[0054]

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(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, n represents 0 or 1, and X ¹ , X ² and X ³ are each independently a hydrogen atom (H) or a heavy atom. Represents a hydrogen atom (D), but at least one is a deuterium atom (D)
And Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom, and W represents a bromine atom or an iodine atom. Two or more compounds represented by the formula (1) are different from each other in the number and / or substitution position of the deuterium atoms (D) in X ^{1 to} X ³ , and (2) R ¹ , n, Y ¹ ; Y ² and W are the same, and the general formula (I
A mixture of two or more compounds represented by formula (I) (hereinafter referred to as a mixture of formula (II)) and a compound represented by formula (II)
I)

[0056]

[Chemical 9]

(Wherein Y ³ , Y ⁴ , Y ⁵ and Z have the same meanings as in formula (I)) and a phenylacetylene derivative represented by the formula (I) in a solvent in the presence of a palladium catalyst and a copper catalyst. It can be obtained by reacting with. The palladium catalyst is preferably, for example, a palladium (II) complex such as dichlorobis (triphenylphosphine) palladium (II) or a palladium (0) complex such as tetrakis (triphenylphosphine) palladium (0), and the copper catalyst is, for example, Copper (I) salts such as copper (I) iodide are preferred. As the solvent, an aprotic polar solvent is preferable, and dimethylformamide (DMF) is particularly preferable.
Further, it is particularly preferable to coexist with an amine solvent,
As the amine solvent, for example, triethylamine is preferable.

Alternatively, the mixture of general formula (I) also comprises
The mixture of general formula (II) was treated with 2-methyl-3-butyn-2-ol under the same conditions as above.

[0059]

[Chemical 10]

By reacting with the general formula (IV)

[0061]

[Chemical 11]

(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, n represents 0 or 1, and X ¹ , X ² and X ³ are each independently a hydrogen atom (H) or a heavy atom. Represents a hydrogen atom (D), but at least one is a deuterium atom (D)
And Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom. ), Two or more compounds represented by the formula (1) are different from each other in the number and / or substitution position of deuterium atoms (D) in X ^{1 to} X ³ , and (2) are R ¹ , n, Y ¹ and Y ² is the same,
A mixture (hereinafter referred to as a mixture of the general formula (IV)) consisting of two or more compounds represented by the general formula (IV) is obtained.

[0063]

[Chemical 12]

(Wherein Y ³ , Y ⁴ , Y ⁵ and Z have the same meanings as in formula (I) and W'represents a bromine atom or an iodine atom) under the conditions described above. It can also be obtained by reacting with.

Here, the mixture of the general formula (II) is represented by the general formula (VI)

[0066]

[Chemical 13]

It can be produced from the cyclohexanone derivative of as follows. By reacting the compound of the general formula (VI) with heavy water in the presence of a base catalyst, the compound of the general formula (VI ′)

[0068]

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(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, n represents 0 or 1, and X ¹ , X ² , X
³ and X ⁴ each independently represent a hydrogen atom (H) or a deuterium atom (D), but at least one represents a deuterium atom (D). ) Two or more compounds represented by
(1) The number and / or substitution position of deuterium atoms (D) in X ^{1 to} X ⁴ are different from each other, and (2) R ¹ and n are the same as each other, the general formula (V
A mixture of two or more compounds represented by I ') (hereinafter referred to as a mixture of general formula (VI')) is obtained. The reaction is preferably carried out in an aprotic solvent, with dichloromethane being particularly preferred. Preferred bases are alkali metal alcoholates, especially sodium methoxide. The reaction is carried out at room temperature to the reflux temperature of the solvent, but it is preferably carried out at 30 ° C. to the reflux temperature of the solvent in order to shorten the reaction time. Further, the reaction is preferably carried out in the presence of a phase transfer catalyst, and a quaternary ammonium salt such as tetrabutylammonium bromide is particularly preferable.

The mixture of the general formula (VI ') is added to the mixture of the general formula (VII).

[0071]

[Chemical 15]

(Wherein Y ¹ and Y ² have the same meanings as in the general formula (I), and M is MgCl, MgBr, Mg
Represents I or Li. ) Of the organometallic reactant,
Then, by dehydrating in the presence of an acid catalyst, the compound of the general formula (VIII)

[0073]

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(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, n represents 0 or 1, and X ¹ , X ² and X ³ are each independently a hydrogen atom (H) or a heavy atom. Represents a hydrogen atom (D), but at least one is a deuterium atom (D)
And Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom. ), Two or more compounds represented by the formula (1) are different from each other in the number and / or substitution position of deuterium atoms (D) in X ^{1 to} X ³ , and (2) are R ¹ , n, Y ¹ and Y ² is the same,
A mixture of two or more compounds represented by the general formula (VIII) (hereinafter referred to as a mixture of the general formula (VIII)) is obtained.

Here, ^one of X ^{1 to} X ⁴ is eliminated during dehydration, but since X ^{1 to} X ⁴ are not particularly distinguished, if X ⁴ is eliminated for convenience. There is no problem in considering it.

Next, the mixture of the general formula (VIII) is hydrogenated, and if necessary, isomerized to the trans form, and then iodinated or brominated to give the general formula (I).
A mixture of I) can be obtained. The reaction may be carried out directly with iodine or bromine, or can be obtained by nitration, reduction, and subsequent aniline derivative diazo decomposition (Sandmeyer reaction). In particular, Y ¹ = Y ² =
In the case of F, it can also be obtained by forming a phenyllithium derivative with alkyllithium such as butyllithium and then reacting it with bromine or iodine.

Further, the phenylacetylene derivative of the general formula (III) is obtained by reacting the compound of the general formula (V) with 2-methyl-3.
-Butyn-2-ol can be obtained in the same manner as described above.

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

[0079]

[Table 1]

[0080]

[Table 2]

(In the table, Cr is a crystalline phase, S is a smectic phase, SA is a smectic A phase, N is a nematic phase, and I is an isotropic liquid phase. The ratio of the number of deuterium atoms (D) to the total number of X ^{1 to} X ³ in the mixture is shown.) The mixture of the general formula (I) of the present invention is not deuterium-substituted, but is the same. Compared with a single compound having a skeleton,
It has an excellent feature that crystals are not precipitated even in a low temperature region.

As such an example, a host liquid crystal (M) for nematic liquid crystal which is currently widely used.

[0083]

[Chemical 17]

80% by weight and shown in Table 1 (N
o. 2), (No. 9), (No. 13), (No. 1)
Liquid crystal compositions (M-2), (M-9), (M-13), each of which comprises 20% by weight of each mixture of 4) and (No. 15).
(M-14) and (M-15) were prepared, respectively. Furthermore, for comparison, the host liquid crystal (M) was added to the formulas (R-2) and (R-
9), (R-13), (R-14) and (R-15)

[0085]

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A liquid crystal composition (MR-2) comprising 20% by weight of the compound of 80% by weight and the same host liquid crystal (M) 80% by weight,
(MR-9), (MR-13), (MR-14) and (MR-15) were prepared, respectively.

These liquid crystal compositions were prepared at low temperature (about -25 ° C).
When stored in (M-2), (M-9), (M-1
In 3), (M-14) and (M-15), precipitation of crystals was not observed even after standing for 2 weeks. On the other hand, (MR
-2), (MR-9), (MR-13), (MR-1)
In 4) and (MR-15), precipitation of crystals was observed within 2 weeks although they were all trace amounts.

Next, a low-viscosity host liquid crystal (N) for active matrix

[0089]

[Chemical 19]

70% by weight and shown in Table 1 (N
o. 9), (No. 13), (No. 14), (No.
Liquid crystal compositions (N-9) and (N-1) comprising 30% by weight of each mixture of (15), (No. 16) and (No. 18).
3), (N-14), (N-15), (N-16) and (N-18) were prepared, respectively. Further, for comparison, 70% by weight of the host liquid crystal (N) and the formulas (R-9) and (R-1) corresponding to each of the above mixtures but not deuterium-substituted.
3), (R-14), (R-15), (R-16) and (R-18)

[0091]

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Liquid crystal compositions (NR-9), (NR-13), (NR-14) and (N
R-15), (NR-16) and (NR-18) were prepared, respectively. When these compositions were similarly stored at −25 ° C., they all crystallized, but their melting points were measured and found to be 28 ° C. for (NR-9), whereas (N−9).
In 9), it was as low as 24 ° C. Similarly, (N-13),
(N-14), (N-15), (N-16) and (N-
18) has melting points of 37 ° C, 13 ° C, 12 ° C, 44, respectively.
℃ and 42 ℃, (NR-13), (NR-1
4), (NR-15), (NR-16) and (NR-1)
8) is 43 ℃, 18 ℃, 16 ℃, 51 ℃ and 4 respectively
It was considerably lower than 7 ° C.

From the above, the mixture of the deuterium-substituted compounds of the general formula (I) according to the present invention has a low melting point and is excellent in that it is difficult to precipitate crystals in the mixed liquid crystal even in a low temperature region. It is obvious that it is extremely useful as a constituent material of a liquid crystal display device, which has characteristics and is expected to be used in a low temperature region.

[0094]

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.

Regarding the structure of the compound, a known compound not deuterated was compared with a capillary gas chromatograph and a thin layer chromatograph, and the same retention time (or R
f value), and nuclear magnetic resonance spectrum (NM
R), confirmed by mass spectrum (MS). Also,
The D conversion rate of the whole mixture was measured by NMR,
The NMR used for the measurement is JNM-G manufactured by JEOL Ltd.
SX400 (400 MHz ¹ H). The D conversion rate of the mixture of the general formula (I) is the intermediate of the general formula (II)
The D conversion rate of the mixture was used as it was.

In the structural formulas shown below, ring D is a ring in which the cyclohexane or cyclohexanone ring is deuterium-substituted (D is the general formula (I), (II),
In (IV), (VI ′), etc., X ^{1 to} X ³ or X
It is substituted at the positions shown by ^{1 to} X ⁴ . ), And d ₃ − (or d ₄ −) described in the compound name is a mixture in which up to 3 (or 4) of hydrogen atoms at that position of the cyclohexane ring are deuterium-substituted. Shall be represented. Further, "%" in the composition represents "% by weight".

Reference Example 1 Deuteration of 4-propylcyclohexanone

[0098]

[Chemical 21]

24 g of sodium methoxide was dissolved in 130 ml of heavy water (D conversion rate 99.8%). To this was added 185 g of 4-propylcyclohexanone dissolved in 200 ml of dichloromethane, and the mixture was heated with stirring at the reflux temperature of the solvent for 6 hours. After cooling, the organic layer was separated, and the aqueous layer was extracted with dichloromethane and then collected. The organic layers were combined, washed with water, and dehydrated and dried over anhydrous sodium sulfate.

The solvent was distilled off, and 2,2,6,6-d ₄ -4 in which the 2- and 6-positions of the cyclohexanone ring were deuterium-substituted.
180 g of -propylcyclohexanone was obtained. No impurities were formed by analysis by thin layer chromatography (TLC) and capillary gas chromatography. When the D conversion rate was measured by NMR, it was about 7
It was 0%.

(Reference Example 2) Deuteration of ₄ -ethylcyclohexanone ₄ -ethylcyclohexanone was deuterated in the same manner as in Reference Example 1 to obtain 2,2,6,6-d ₄ -4-ethylcyclohexanone. . When the D conversion rate was measured by NMR, it was about 65%.

Reference Example 3 Deuteration of ₄ -butylcyclohexanone ₄ -butylcyclohexanone was deuterated in the same manner as in Reference Example 1 to obtain 2,2,6,6-d ₄ -4-butylcyclohexanone. . When the D conversion rate was measured by NMR, it was about 76%.

Reference Example 4 Deuteration of ₄ -pentylcyclohexanone In the same manner as in Reference Example _4, 4-pentylcyclohexanone was deuterated to obtain 2,2,6,6-d ₄ -4-pentylcyclohexanone. . When the D conversion rate was measured by NMR, it was about 80%.

Reference Example 5 4-Propylbicyclohexane-4-one Deuteration 4-Propylbicyclohexane-4-one was prepared in the same manner as in Reference Example 1.
Deuteration of 4-one gave 2,2,6,6-d ₄ -4-propylbicyclohexane- ₄ -one. When the D conversion rate was measured by NMR, it was about 83%.

(Example 1) 1- (4-fluorophenyl)
Le) ethynyl-4- (2,2,6-d ₃-Transformer-4
-Propyl) cyclohexylbenzene (Table 1, No. 1
A mixture of

[0106]

[Chemical formula 22]

(1-a) Synthesis of (2,2,6-d ₃ -trans-4-propylcyclohexyl) benzene 25.2 g of magnesium was suspended in 50 ml of tetrahydrofuran (THF). To this, a solution of 148 g of bromobenzene in 740 ml of THF was added dropwise in a stream of nitrogen at a rate at which gentle reflux was maintained. After completion of dropping, the mixture was stirred for 1 hour and cooled with ice. 2, 2, 6 obtained in Reference Example 1
6-d _{4-4-propyl-cyclohexanone} 101.4g
A THF (500 ml) solution was added dropwise so that the internal temperature did not exceed 10 ° C. After completion of the dropping, the mixture was stirred for 1 hour and neutralized by adding water and then dilute hydrochloric acid. After separating the organic layer, the aqueous layer was extracted with toluene, combined with the organic layer, and washed with water and then saturated brine. 2,2,6,6-d ₄ -obtained by distilling off the solvent
1-Phenyl-4-propylcyclohexanol was dissolved in 800 ml of toluene, 4.0 g of potassium hydrogen sulfate was added, and the mixture was heated under reflux for 2 hours. After cooling, washed with saturated aqueous sodium bicarbonate followed by water, was dehydrated and dried over anhydrous sodium sulfate, the solvent was distilled off, 2,2,6-d ₃
-1-Phenyl-4-propyl-1-cyclohexene 1
52 g were obtained. The whole amount was dissolved in 750 ml of ethyl acetate, 15 g of palladium carbon was added, and the mixture was stirred in an autoclave at a hydrogen pressure of 3 Kg / cm ² for 7 hours at room temperature. After the catalyst was filtered off, the solvent was distilled off to obtain a crude product (trans / cis mixture of cyclohexane ring) dissolved in 450 ml of N, N-dimethylformamide (DMF), and 65 g of potassium t-butoxide was added, The mixture was heated and stirred at 110 ° C. for 6 hours. After cooling to room temperature, 500 ml of water was added, then 250 ml of dilute hydrochloric acid was added to weakly acidify, and the mixture was extracted twice with 500 ml of hexane. The hexane layers were combined, washed with water and then saturated brine, and dried over anhydrous sodium sulfate. After distilling off the solvent, distillation under reduced pressure (122-1
27 ° C / 1 mmHg) (2,2,6-d ₃ -transformer-
129 g of 4-propylcyclohexyl) benzene was obtained.

(1-b) Synthesis of 1- (2,2,6-d ₃ -trans-4-propylcyclohexyl) -4-iodobenzene (2,2,6-obtained in (1-a) above) d ₃ -transformer-
50 g of 4-propylcyclohexyl) benzene, 37.7 g of iodine and 28.2 g of periodic acid dihydrate were added to acetic acid 2
Dissolve in 00 ml, sulfuric acid 6 ml, water 40 ml and 1,2-
20 ml of dichloroethane was added, and the mixture was heated under reflux for 1 hour. After cooling, 200 ml of water was added, and the mixture was extracted twice with 250 ml of toluene. The extract was washed with a 10% sodium sulfite aqueous solution, water and saturated saline, and then dried and dried over anhydrous sodium sulfate. After distilling off the solvent, recrystallize from ethanol,
1- (2,2,6-d ₃ - trans-4-propyl-cyclohexyl) -4-iodobenzene 52.2 g.

(1-c) Synthesis of 1- (2,2,6-d ₃ -trans-4-propylcyclohexyl) -4-ethynylbenzene 1- (2,2, obtained in (1-b) above. 13.3 g of 6-d ₃ -trans-4-propylcyclohexyl) -4-iodobenzene was dissolved in 40 ml of DMF and 40 ml of triethylamine, and 0.20 g of dichlorobis (triphenylphosphine) palladium (II) and copper (I) iodide were added. ．
15 g was added, and then 2-methyl-3-butyn-2-ol 5.1 g was added dropwise over 30 minutes. After stirring at room temperature for 1 hour, 50 ml of water was added, and the mixture was extracted twice with 100 ml of ethyl acetate. After washing twice with water and then with saturated saline, it was dried over anhydrous sodium sulfate. The solvent is distilled off and 4- [4-
(2,2,6-d ₃ - trans-4-propyl-cyclohexyl) phenyl] -2-methyl-3-butyn-2-ol 11.5 g. The whole amount was dissolved in 70 ml of toluene, 2.4 g of sodium hydroxide was added, and the mixture was heated under reflux for 1 hour. After allowing to cool, water was added and then neutralized with dilute hydrochloric acid. After separating the organic layer, the organic layer was washed with water and then with saturated saline, and dried over anhydrous sodium sulfate. After distilling off the solvent, it was purified by silica gel column chromatography (hexane) 1- (2,2,6-d ₃ - trans-4-propyl-cyclohexyl) -4-ethynyl benzene 8.4 g.

(1-d) 1- (4-fluorophenyl) ethynyl-4- (2,2,6-d ₃ -trans-4
Synthesis of -propyl) cyclohexylbenzene 6.2 g of 1-bromo-4-fluorobenzene was added to DMF6.
0 ml and 24 ml of triethylamine and dissolved in dichlorobis (triphenylphosphine) palladium (II).
2 g and copper (I) iodide 0.15 g were added, and 1- (2,2,6-d ₃ -trans-obtained in the above (1-c) was added thereto.
6.6 g of 4-propylcyclohexyl) -4-ethynylbenzene was added dropwise over 30 minutes, and then the mixture was heated with stirring at 80 ° C. for 3 hours. After allowing to cool, add 60 ml of water and add 30 m of toluene.
Extracted twice with 1. After washing twice with water and then with saturated saline, it was dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified by silica gel column chromatography (hexane) and recrystallized from ethanol to give 1- (4-fluorophenyl) ethynyl-4- (2,2,6-d ₃ -trans-4-. 5.9 g of propyl) cyclohexylbenzene was obtained. The D conversion rate of this mixture was about 70%. Also,
The melting point was 85 ° C. and showed a nematic phase up to 187 ° C.

Comparative Example 1 Synthesis of 1- (4-fluorophenyl) ethynyl-4- (trans-4-propyl) cyclohexylbenzene In Example 1, 2,2,6,6-d ₄ -4-propyl 1- (4-Fluorophenyl) ethynyl-4- (trans-4-propyl) cyclohexylbenzene was obtained in the same manner except that 4-propylcyclohexanone was used instead of cyclohexanone. The melting point of this compound is 90
C and higher than the compound of Example 1. The maximum temperature of the nematic phase was 189 ° C.

Example 2 1- (3,4-Difluorophenyl) ethynyl-4- (2,2,6-d ₃ -trans-4-propyl) cyclohexylbenzene (Table 1, N
o. 2 mixture) in the same manner as in Example 1 except that 1-bromo-4-fluorobenzene was used in place of 1-bromo-4-fluorobenzene in the above (1-d), and 1- (3,4-
Difluorophenyl) ethynyl-4- (2,2,6-d
₃ -trans-4-propyl) cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 3) 1- (3-fluoro-4-)
Cyanophenyl) ethynyl -4- (2,2,6-d ₃ -
Synthesis of trans-4-propyl) cyclohexylbenzene (mixture of No. 3 in Table 1) In the above (1-d), 1-bromo-3-fluoro-4-cyano was used instead of 1-bromo-4-fluorobenzene. 1- (3) in the same manner as in Example 1 except that benzene was used.
-Fluoro-4-cyanophenyl) ethynyl-4-
(2,2,6-d ₃ - trans-4-propyl) was obtained cyclohexylbenzene. D conversion rate and phase transition temperature are first
It is summarized in the table.

(Example 4) 1- (3-fluoro-4-)
Methoxyphenyl) ethynyl-4- (2,2,6-d ₃
Synthesis of -trans-4-propyl) cyclohexylbenzene (mixture of No. 4 in Table 1) In the above (1-d), 1-bromo-3-fluoro-4- was used instead of 1-bromo-4-fluorobenzene. In the same manner as in Example 1 except that methoxybenzene was used, 1-
(3-Fluoro-4-methoxyphenyl) ethynyl-4
- (2,2,6-d ₃ - trans-4-propyl) was obtained cyclohexylbenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 5 1- (4-Butylphenyl) ethynyl-4- (2,2,6-d ₃ -trans-4
-Propyl) cyclohexylbenzene (Table 1, No. 5
1- (4-) in the same manner as in Example 1 except that 1-bromo-4-fluorobenzene was used instead of 1-bromo-4-fluorobenzene in the above (1-d). butylphenyl) ethynyl -4- (2,2,6-d ₃ - trans-4
-Propyl) cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 6 1- (2-Methyl-4-butylphenyl) ethynyl-4- (2,2,6-d ₃ -trans-4-propyl) cyclohexylbenzene (first
Table No. The mixture of 6) was synthesized in the same manner as in Example 1 except that 1-bromo-4-fluorobenzene was used instead of 1-bromo-4-fluorobenzene in the above (1-d), 1- (2-
Methyl-4-butylphenyl) ethynyl-4- (2,2
2,6-d ₃ - was obtained trans-4-propyl) cyclohexylbenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 7) 1- (2,3-difluoro-4-ethoxyphenyl) ethynyl-4- (2,2,6)
Synthesis of -d ₃ -trans-4-propyl) cyclohexylbenzene (mixture of No. 7 in Table 1) In the above (1-d), 1-bromo-2,3 was used instead of 1-bromo-4-fluorobenzene. -Difluoro-4-
In the same manner as in Example 1 except that ethoxybenzene was used,
1- (2,3-difluoro-4-ethoxyphenyl) ethynyl -4- (2,2,6-d ₃ - trans-4-propyl) was obtained cyclohexylbenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

[0118] (Example 8) 1- (3,4,5-trifluorophenyl) ethynyl -4- (2,2,6-d ₃ -
Trans-4-ethyl) cyclohexylbenzene (first
Table No. (Mixture of 8) (8-a) Synthesis of 1-ethynyl-3,4,5-trifluorobenzene

[0119]

[Chemical formula 23]

300 g of 1-bromo-3,4,5-trifluorobenzene was dissolved in 900 ml of DMF and 300 ml of triethylamine, and 5.0 g of dichlorobis (triphenylphosphine) palladium (II) and copper (I) iodide were dissolved.
1.4 g was added and stirred at 50 ° C. To this, 144 g of 2-methyl-3-butyn-2-ol was added dropwise over 1.5 hours. After completion of the dropping, the mixture was heated and stirred at 80 ° C. for 30 minutes, and allowed to cool to room temperature. 1200 ml of water was added, and the mixture was extracted twice with 700 ml of hexane. The organic layers were combined and washed twice with water and once with saturated brine. It was dried over anhydrous sodium sulfate, the solvent was distilled off, and the obtained crude product was distilled under reduced pressure (96 to 10).
The mixture was subjected to 0 ° C / 1 mmHg) to obtain 275 g of 4- (3,4,5-trifluorophenyl) -2-methyl-3-butyn-2-ol.

Sodium hydroxide (0.7 g) was added to this 70 g, and the resulting acetone was distilled off while heating and stirring at 120 ° C. After the acetone stopped distilling, the mixture was allowed to cool to room temperature, then decompressed to about 50 mmHg, and distilled under heating (60 ° C / 46 mmHg) to give an oily 1-ethynyl-
47 g of 3,4,5-trifluorobenzene was obtained.

(8-b) Synthesis of 1- (3,4,5-trifluorophenyl) ethynyl-4- (2,2,6-d ₃ -trans-4-ethyl) cyclohexylbenzene Obtained in Reference Example 2. from 2,2,6,6-d ₄ 4-ethyl cyclohexanone, which is (1-a), (1 -b) in analogy to 1- (2,2,6-d ₃ - trans-4-ethyl- Cyclohexyl) -4-iodobenzene was obtained. This 5
0.6 g and 1-ethynyl-3 obtained in (8-a),
29.8 g of 4,5-trifluorobenzene was added to DMF25.
It is dissolved in 0 ml and 25 ml of triethylamine, and dichlorobis (triphenylphosphine) palladium (II) 1.
1 g and 0.3 g of copper (I) iodide were added, and the mixture was stirred at 45 ° C. for 3 hours. After standing to cool, add 250 ml of water and add toluene 40
It was extracted with 0 ml and washed with dilute hydrochloric acid, water and saturated saline. The crude product obtained by drying over anhydrous sodium sulfate and distilling off the solvent was purified by silica gel column chromatography (hexane), and recrystallized twice from ethanol to give 1- (3,4,5-triene). fluorophenyl) ethynyl -4- (2,2,6-d ₃ - trans-4-ethyl)
42.8 g of cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

[0123] (Example 9) 1- (3,4,5-trifluorophenyl) ethynyl -4- (2,2,6-d ₃ -
Synthesis of trans-4-propyl) cyclohexylbenzene (mixture of Table 1, No. 9) In Reference Example 1, substituting 2,2,6,6-d ₄ -4-ethylcyclohexanone in the above (8-b). Got 2,
Except for using 2,6,6-d ₄ -4- propyl cyclohexanone in the same manner as in Example 8, 1- (3,4,5-trifluorophenyl) ethynyl-4- (2,2,6 d
₃ -trans-4-propyl) cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 10) 1- (3,4,5-trifluorophenyl) ethynyl-4- (2,2,6-d _3).
- instead of trans-4-) 2,2,6,6-d ₄ 4-ethyl-cyclohexanone in Synthesis of (8-b) of cyclohexylbenzene (mixture of Table 1 No.10), Example 3 except for using 2,2,6,6-d ₄ -4- butyl cyclohexanone obtained in the same manner as in example 8, 1- (3,4,5
Trifluorophenyl) ethynyl-4- (2,2,6-
d ₃ - the trans-4-butyl) cyclohexyl benzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 11 3,3,5-d ₃ -trans-4- [4- (4-butylphenylethynyl) phenyl] -trans-4′-propylbicyclohexane (Table 1, No. 11) Mixture) 2,2,6, obtained in Reference Example 5 in place of 2,2,6,6-d ₄ -4-propylcyclohexanone in Example 5.
6-d ₄ 4-propyl except for using bicyclohexane-4-one in the same manner, 3,3,5-d ₃ - trans -
4- [4- (4-butylphenylethynyl) phenyl]
-Trans-4'-propylbicyclohexane was obtained.
The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 12) 1- (4-fluorophenyl) ethynyl-2-fluoro-4- (2,2,6-d)
Synthesis of ₃ -trans-4-pentyl) cyclohexylbenzene (mixture of No. 12 in Table 1) In the above (1-a), 2,2,6,6-d ₄ -4-
2,2,6,6-d ₄ -4-pentylcyclohexanone obtained in Reference Example 4 was used instead of propylcyclohexanone, and 1-bromo-3-fluorobenzene was used instead of bromobenzene. 1 as in Example 1
-(4-Fluorophenyl) ethynyl-2-fluoro-
4- (2,2,6-d ₃ - trans-4-pentyl) to give the cyclohexylbenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 13) 1- (4-methylphenyl) ethynyl-2,6-difluoro-4- (2,2,6)
-D ₃ - Synthesis of trans-4-propyl) cyclohexyl benzene (mixture of Table 1 No.13)

[0128]

[Chemical formula 24]

(13-a) 1- (2,2,6-d _3-
Synthesis of trans-4-propyl) cyclohexyl-3,5-difluorobenzene In the above (1-a), bromobenzene was used instead of 3,
1- (2,2,6-d ₃ -trans-4-propyl) cyclohexyl-3,5-difluorobenzene was obtained in the same manner except that 5-difluoro-1-bromobenzene was used.

(13-b) 1- (2,2,6-d _3-
Trans-4-propyl) was obtained above cyclohexyl-3,5-difluoro-4-iodobenzene (13-a) 1- (2,2,6 -d 3 - trans-4-propyl) cyclohexyl -3 , 5-difluorobenzene (14.8 g) was dissolved in THF (60 ml),
Cooled to 50 ° C. Under a nitrogen atmosphere, 45 ml of n-butyllithium (1.68M, n-hexane solution) was added dropwise over 20 minutes, and the mixture was stirred at the same temperature for 30 minutes. A solution of 17.4 g of iodine in 180 ml of THF was added dropwise thereto at the same temperature for 30 minutes, and the mixture was stirred at -50 ° C for 30 minutes. After adding 50 ml of water, the mixture was returned to room temperature, neutralized with diluted hydrochloric acid, the organic layer was separated, and then extracted from the aqueous layer with 100 ml of hexane.
The organic layers were combined, washed with water and then saturated brine, and dried over anhydrous sodium sulfate. The solvent is distilled off and 1- (2
2,6-d ₃ - trans-4-propyl) cyclohexyl-3,5-difluoro-4-iodobenzene crystal 2
2.0 g was obtained.

(13-c) 1- (2,2,6-d _3-
Trans-4-propyl) was obtained above cyclohexyl-3,5-difluoro-4-ethynyl benzene (13-b) 1- (2,2,6 -d 3 - trans-4-propyl) cyclohexyl -3 , 5-Difluoro-4-iodobenzene to give 1- (2,2,6-d ₃ -trans-4-propyl) cyclohexyl-3,5-difluoro-4-ethynylbenzene in the same manner as (1-c). Got

(13-d) 1- (4-methylphenyl) ethynyl-2,6-difluoro-4- (2,2,6)
-D ₃ - was obtained trans-4-propyl) cyclohexyl benzene Synthesis of (13-c) 1- (2,2,6 -d 3 - trans-4-propyl) cyclohexyl-3,5-difluoro-4 1- (4-methylphenyl) ethynyl-2,6-difluoro-4- (2,2,6) from -ethynylbenzene and 4-bromotoluene in the same manner as (1-d).
-D ₃ - was obtained trans-4-propyl) cyclohexylbenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 14 1- (4-trifluoromethoxyphenyl) ethynyl-2,6-difluoro-4
- (2,2,6-d ₃ - trans-4-propyl) Synthesis Example 13 of cyclohexylbenzene (mixture of Table 1 No.14), instead of 4-bromotoluene, 1
1- (4-trifluoromethoxyphenyl) ethynyl-2,6-difluoro-4- (2,2,2
6-d ₃ -trans-4-propyl) cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 15 1- (3,4-difluorophenyl) ethynyl-2,6-difluoro-4-
Synthesis of (2,2,6-d ₃ -trans-4-propyl) cyclohexylbenzene (mixture of Table 1, No. 15) In Example 13, instead of 4-bromotoluene, 1
1- (3,4-difluorophenyl) ethynyl-2,6-difluoro-4- (2,2,6-d ₃ -trans-) was used in the same manner except that -bromo-3,4-difluorobenzene was used. 4-Propyl) cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 16) 1- (3,4,5-trifluorophenyl) ethynyl-2,6-difluoro-4
- (2,2,6-d ₃ - trans-4-propyl) Synthesis Example 13 of cyclohexylbenzene (mixture of Table 1 No.16), instead of 4-bromotoluene, 1
1- (3,4,5-trifluorophenyl) ethynyl-2,6-difluoro-4- (2,2,2,2,6-trifluorophenyl) ethynyl-2,6-difluoro-4- (2,2,2)
6-d ₃ -trans-4-propyl) cyclohexylbenzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 17 1- (4-chloro-3,
5-difluorophenyl) ethynyl-2,6-difluoro -4- (2,2,6-d ₃ - Synthesis Example 13 trans-4-propyl) cyclohexyl benzene (mixture of Table 1 No.16), Replace with 4-bromotoluene, 1
1- (4-chloro-3,5-difluorophenyl) ethynyl-2,6-difluoro-4 was obtained in the same manner except that -bromo-4-chloro-3,5-difluorobenzene was used.
- (2,2,6-d ₃ - trans-4-propyl) was obtained cyclohexylbenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 18) 3,3,5-d ₃ -trans-4- [4- (3,4,5-trifluorophenylethynyl) -3,5-difluorophenyl] -trans-4′- Propylbicyclohexane (Table 1, No. 18
From 2,2,6,6-d ₄ 4-propyl-bicyclohexane-4-one obtained in Reference Example 5 in the mixture) in the same manner as in Example 16, 3,3,5-d ₃ - Trans-4- [4- (3,
4,5-Trifluorophenylethynyl) -3,5-difluorophenyl] -trans-4′-propylbicyclohexane was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 19 Preparation of Liquid Crystal Composition (1)

[0139]

[Chemical 25]

(In the formula, the cyclohexane ring represents a trans configuration.), And a host liquid crystal (M) which is currently widely used as a nematic liquid crystal was prepared. Host liquid crystal (M)
Shows a nematic phase at 54.5 ° C or lower, and did not crystallize even when left at -40 ° C.

80% of this host liquid crystal (M) and Example 2
When a liquid crystal composition (M-1) consisting of 20% of the mixture of (No. 2) obtained in 1. was prepared, the nematic phase maximum temperature (T _NI ) was 71 ° C. This is a low temperature (about -25
When it was stored for 2 weeks, no precipitation of crystals or phase separation was observed.

Similarly, the host liquid crystal (M) 80% and (N
o. 9), (No. 13), (No. 14) and (N
o. 15% of the mixture of the liquid crystal composition (M-
9), (M-13), (M-14) and (M-15) were prepared, respectively. The T _{NI of} each composition was as follows. (M-9): T _NI 64 ° C. (M-13): T _NI 75 ° C. (M-14): T _NI 67.5 ° C. (M-15): T _NI 61 ° C. These still have the same temperature (-25 However, no precipitation of crystals or phase separation was observed even after standing for 2 weeks.

(Comparative Example 2) The compound (R) corresponding to each mixture of the present invention used in Example 19 but not substituted with deuterium was used.
-2), (R-9), (R-13), (R-14) and (R-15).

[0144]

[Chemical formula 26]

A liquid crystal composition (MR-2) or (MR-2) comprising 20% of the compound of the above and 80% of the same host liquid crystal (M).
-9), (MR-13), (MR-14) and (MR-
15) was prepared respectively. The T _{NI of} each composition was as follows. (MR-2): _TNI 71.5 ° C (MR-9): _TNI 64.5 ° C (MR-13): _TNI 75 ° C (MR-14): _TNI 68 ° C (MR-15): T _NI 61 ° C. When these were stored at room temperature, precipitation of all crystals was observed within 2 weeks. Therefore, the mixture of the present invention is
It is clear that the composition is less likely to crystallize as compared to the corresponding non-deuterium substituted compound.

Example 20 Preparation of Liquid Crystal Composition (2)

[0147]

[Chemical 27]

(In the formula, the cyclohexane ring has a trans configuration.) A fluorine-based host liquid crystal (N) particularly suitable for an active matrix was prepared. As a result, a nematic (N) phase at 116.7 ° C. or lower was obtained. And its melting point was 11 ° C.

A liquid crystal composition (N) consisting of 70% of this host liquid crystal (N) and 30% of the mixture of Table 1 (No. 13).
-13) was prepared. The T _{NI of} this composition is 140.5
It became as high as ℃. This composition (N-13) was cooled to room temperature (about 2
It was stored at 5 ° C.) for 1 week, but no precipitation of crystals was observed. On the other hand, when this composition (N-13) was stored at -25 ° C., it crystallized, but when its melting point was measured,
It was 37 ° C.

Similarly, (No. 9) and (No. 1)
4), (No. 15), (No. 16) and (No. 1)
30% of the mixture of 8) and 70% of the same host liquid crystal (N)
(N-9), (N-14), (N-15),
Each composition of (N-16) and (N-18) was prepared, and its T _NI was measured. The results are shown below. Further, when each composition was similarly stored at −25 ° C. and all were crystallized, their melting points are also shown. _{(N-9): T NI} 107.5 ℃, melting point 24 ℃ (N-14): T NI 125 ℃, melting point 13 ℃ (N-15): T NI 113 ℃, melting point 12 ℃ (N-16): T _NI 103 ° C., melting point 44 ° C. (N-18): T _NI 124.5 ° C., melting point 42 ° C.

(Comparative Example 3) Formula (R-9) corresponding to each mixture used in Example 20, but not deuterium-substituted,
(R-13), (R-14), (R-15), (R-1
6) and (R-18)

[0152]

[Chemical 28]

A liquid crystal composition (NR-9), (NR-9), which comprises 30% of the compound of 70% and 70% of the same host liquid crystal (N)
-13), (NR-14), (NR-15), (NR-
16) and (NR-18), respectively, and -25 ° C
It was crystallized when stored in. Its melting point and T
_NI is shown below. (NR-9): T _NI 125.5 ° C., melting point 28 ° C. (NR-13): T _NI 141 ° C., melting point 43 ° C. (NR-14): T _NI 125 ° C., melting point 18 ° C. (NR-15): T _NI 114 ° C., melting point 16 ° C. (NR-16): T _NI 103.5 ° C., melting point 51 ° C. (NR-18): T _NI 125 ° C., melting point 47 ° C. Therefore, the mixture of the present invention corresponds to the corresponding deuterium. It is clear that the melting point can be lowered with little reduction in the T _NI of the composition compared to the unsubstituted compound.

[0154]

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, the T _NI point is not significantly lowered, the melting point is lowered, the electro-optical characteristics are not lowered, and crystals are not precipitated even in the low temperature region. Excellent effect can be obtained. 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.

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[Procedure amendment]

[Submission date] August 2, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 11

[Correction method] Change

[Correction content]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C09K 19/30 9279-4H G02F 1/13 500 // C07M 5:00

Claims (11)

[Claims] 1. A compound of the general formula (I) (In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, n represents 0 or 1, and X ¹ , X ² and X ³ are each independently a hydrogen atom (H) or a deuterium atom ( D), at least one of which represents a deuterium atom (D), and Y
¹ , Y ² , Y ³ and Y ⁴ each independently represent a hydrogen atom or a fluorine atom, Y ⁵ represents a hydrogen atom, a fluorine atom or a methyl group, and Z is a fluorine atom, a chlorine atom, a hydrogen atom or a cyano group. ^{, -R 2, -OR 2, -CF} 3, -OCF 3,
-OCF represents ₂ H or -OCH ^₂ CF _3, R ₂ represents an alkyl group or an alkenyl group having 3 to 12 carbon atoms having 1 to 12 carbon atoms, the cyclohexane ring is the trans configuration. Two or more compounds represented by the formula (1) are different from each other in the number and / or substitution position of the deuterium atoms (D) in X ^{1 to} X ³ , and (2) R ¹ , n, Y ¹ ; Y
² , Y ³ , Y ⁴ , Y ⁵ and Z are the same, and a mixture of two or more compounds represented by the general formula (I). 2. In the general formula (I), Z is a fluorine atom, a chlorine atom, a cyano group, —R ² , —OR ² or —OCF.
A mixture according to claim 1, characterized in that it represents ₃ and R ² represents an alkyl group having 1 to 12 carbon atoms. 3. The mixture according to claim 2, wherein in the general formula (I), n represents 0 and Y ¹ and Y ² both represent a hydrogen atom. 4. In the general formula (I), Y ⁵ represents a hydrogen atom, Z represents a fluorine atom, a cyano group, —R ² or —O.
Mixture of claim 3, wherein a representative of the R ^2. 5. In the general formula (I), Y^FiveIs a methyl group
Represents Y³And Y ^FourTogether represent a hydrogen atom, and Z is-
R²The mixture according to claim 3, characterized in that 6. In the general formula (I), Y ⁵ represents a fluorine atom, Y ³ represents a fluorine atom, Y ⁴ represents a hydrogen atom, and Z represents —OR ^2. The mixture according to 3. 7. In the general formula (I), n represents 0, at least one of Y ¹ and Y ² represents a fluorine atom, Y ⁵ represents a hydrogen atom, Z represents a fluorine atom, a chlorine atom, mixture of claim 2, wherein a representative of the -R ² or -OR ^2. 8. In the general formula (I), Y ³ and Y ⁴ both represent a hydrogen atom, and Z is a fluorine atom, —R ² or —O.
Mixture according to claim 7, wherein a representative of the R ^2. 9. The mixture according to claim 7, wherein in the general formula (I), at least one of Y ³ and Y ⁴ represents a fluorine atom, and Z represents a fluorine atom or a chlorine atom. 10. In the general formula (I), n represents 1, Y ¹ and Y ² both represent a hydrogen atom or a fluorine atom, Y ³ and Y ⁴ both represent a hydrogen atom or a fluorine atom, and Y ⁵ Represents a hydrogen atom, Z is a fluorine atom or -R ²
The mixture according to claim 2, characterized in that 11. The ratio of the number of deuterium atoms (D) in a mixture of two or more compounds represented by general formula (I) is the total number of X ¹ , X ² and X ³ in general formula (I). The mixture according to claims 1 to 11, characterized in that it is in the range of 30-95%.