JPH0873854A - 4-(2-cyclohexylethyl)cyclohexylbenzene derivative - Google Patents

Abstract

PURPOSE: To obtain a mixture comprising new liquid-crystalline compounds having deuterium atoms, capable of lowering the melting point of the composition without lowering the nematic phase upper limit temperature of the composition, substantially not depositing crystals even at low temperature, an suitable as a material for liquid crystal elements used in a low temperature region. CONSTITUTION: This mixture comprises two or more compounds wherein the number and substituted positions of deuterium (D) atoms are different from each other and R<1> , Y<1> , Y<2> and Z are the same each other, among compounds of formula I [R<1> is a 1-12C alkyl, alkoxyalkyl; X<1> -X<8> are each H, deuterium (D); Y<1> , Y<2> are each H, F; Z is F, cyano, etc.,]. The mixture includes 1-[d4 - trans-4-[2-(trans-4-propylcyclohexyl)ethyl]cyclohexyl]-3,4,5-trifluoro benzene. The mixture of the compounds of formula I can be obtained from a mixture comprising two or more kinds of compounds of formula II and a mixture comprising two or more kinds of compounds of formula III.

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
It relates to a mixture of (2-cyclohexylethyl) cyclohexylbenzene derivatives.

[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 Recently, the TFT (Thin Film Tr) has been replaced by such a simple matrix drive.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]

[Chemical 3]

[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]

[Chemical 5]

(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 or an alkoxyalkyl group having 1 to 12 carbon atoms, and X ¹ , X ² ,
X ³ , X ⁴ , X ⁵ , X ⁶ , X ⁷ and X ⁸ each independently represent a hydrogen atom (H) or a deuterium atom (D), and Y ¹ and Y ² are each independently a hydrogen atom or Represents a fluorine atom, Z is a fluorine atom, a chlorine atom, a hydrogen atom, a cyano group,
_{^{-R 2, -OR 2, -CF 3}} , -OCF 3, represent -OCF ₂ H or -OCH ^₂ CF _3, R ₂ is 1 to 12 carbon atoms
Represents an alkyl group 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 mutually X ^{1 to} X ^8;
Represented by the above general formula (I), wherein the number of deuterium atoms (D) and / or the substitution positions are different, and (2) R ¹ , Y ¹ , Y ² and Z are the same as each other. A mixture of two or more compounds (hereinafter, represented by the general formula (I)
It is a mixture of. )I will provide a.

Among the mixture of the general formula (I), R ¹
Represents a linear alkyl group or an alkoxyalkyl group having 1 to 7 carbon atoms, Z is a fluorine atom, a chlorine atom, a cyano group, a linear alkyl group or an alkoxyl group having 1 to 7 carbon atoms, -OCF ₃ or it is preferable to represent -OCH ₂ CF _3.

More specifically, in the general formula (I) (A), it is preferable that at least one of Y ¹ , Y ² and Z is a fluorine atom, and Z and Y ¹ are both fluorine atoms. It is preferable.

Further, (B) in the general formula (I), Y ¹
It is also preferable that both Y ² and Y ² are hydrogen atoms, and at this time, Z is more preferably a chlorine atom or a cyano group. As mentioned above, the characteristic of the mixture of the general formula (I) is that, in the general formula (I), X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ ,
X ⁷ and X ⁸ each independently represent a hydrogen atom (H) or a deuterium atom (D), and at least one of them.
And the number of deuterium atoms (D) in X ^{1 to} X ⁸ and / or the substitution position in each of the two or more compounds, each of which is a deuterium atom (D). And (2) R ¹ , Y ¹ , Y ² and Z are the same as each other. That is, in the general formula (I), when R ¹ , Y ¹ , Y ² and Z are fixed, the compound of the general formula (I) may have a great variety of compounds including stereoisomers. It will be.

However, as will be described later, it is not industrially advantageous to selectively produce each of these various kinds of 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 state of a mixture composed of several kinds of compounds among various kinds of homologues depending on the number of deuterium atoms (D) and / or the substitution position.

On the contrary, when 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). 20 to 95% of the total number of X ^{1 to} X ⁸
Is preferable, the range of 30 to 90% is more preferable, and the range of 60 to 90% is particularly preferable.

In the mixture of the general formula (I) of the present invention, all of the X ^{1 to} X ⁸ are necessarily the target of the deuterium substitution of the general formula (Ia).

[0052]

Embedded image

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
The configurations of X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² , Z and the cyclohexane ring have the same meanings as in the mixture of the general formula (I). ) Need not consist solely of the compound represented by the formula (I), and in the general formula (I), X ⁵ , X ⁶ , X ⁷ and X ⁸ are hydrogen atoms (H).

[0054]

[Chemical 9]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , Y ¹ ,
The configurations of Y ² , Z and the cyclohexane ring have the same meanings as in formula (I). 2)
One or more compounds are (1) different from each other in the number and / or substitution position of deuterium atoms (D) in X ^{1 to} X ⁴ , and (2) mutually different in R ¹ , Y ¹ , Y ² and Z. A mixture of two or more compounds represented by the general formula (Ib) (hereinafter, referred to as a mixture of the general formula (Ib)) or X ¹ in the general formula (I),
A compound of the general formula (I) in which X ² , X ³ and X ⁴ are hydrogen atoms (H)
c)

[0056]

[Chemical 10]

(Wherein R ¹ , X ⁵ , X ⁶ , X ⁷ , X ⁸ , Y ¹ ,
The configurations of Y ² , Z and the cyclohexane ring have the same meanings as in formula (I). 2)
One or more compounds are (1) different from each other in the number and / or substitution position of deuterium atoms (D) in X ^{5 to} X ⁸ , and (2) R ¹ , Y ¹ , Y ² and Z are the same as each other. A mixture of two or more kinds of the compounds represented by the general formula (Ic) (hereinafter, referred to as a mixture of the general formula (Ic)) is also preferable.

In such a mixture, the compound of the general formula (I
The ratio of the number of deuterium atoms (D) in the mixture of b) is
Deuterium atom (D) for the total number of X ^{1 to} X ⁴ in the general formula (Ib) or in the mixture of the general formula (Ic).
The ratio of the number is, the total number of X ⁵ to X ⁸ in the general formula (Ic), preferably in the range 40 to 95%, respectively, more preferably in the range of 50-90%.

The mixtures of general formula (I) according to the invention are
For example, it can be obtained by the following manufacturing method. General formula (II)

[0060]

[Chemical 11]

Two or more compounds represented by the formula (wherein R ¹ , X ¹ , X ² , X ³ and X ⁴ have the same meanings as in formula (I)) are (1) mutually X ^{1 to} X ⁴ are different in the number and / or substitution position of the deuterium atom (D) and are wound (2) R ^{1 s} are the same as each other, and are represented by the general formula (II) 4- A mixture of two or more substituted cyclohexanone derivatives (hereinafter, represented by the general formula (I
It is a mixture of I). ) And the general formula (III)

[0062]

[Chemical 12]

Two or more compounds represented by the formula (wherein X ⁵ , X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² and Z have the same meanings as in formula (I)), (1) Mutually X ^{5 to} X ⁸
The number of the deuterium atom (D) and / or the substitution position in, and (2) Y ¹ , Y ² and Z are the same as each other, represented by the above general formula (III) 4
-A mixture of two or more phenylcyclohexanone derivatives (hereinafter referred to as a mixture of general formula (III)) can be produced, for example, as follows. (Production method a)

[0064]

[Chemical 13]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² and Z have the same meanings as in formula (I). ) The mixture of the general formula (II) is represented by the general formula (V) by reacting the mixture of the general formula (II) with the Wittig reagent of the formula (IV), followed by acid treatment, and then isomerizing the cyclohexane ring to the trans configuration with a base. (1) Deuterium atom (D) at X ^{1 to} X ⁴
Different in the number and / or substitution position, and (2) are mutually R
^A mixture of two or more cyclohexanecarbaldehyde derivatives represented by the general formula (V), wherein ¹ is the same, is obtained (hereinafter referred to as the mixture of the general formula (V)). By reacting this again with the compound of the formula (IV) and acid-treating, two or more compounds represented by the general formula (VI) are (1) mutually deuterium atoms (D) in X ^{1 to} X ⁴ . Of the cyclohexaneethanal derivative represented by the general formula (VI), characterized in that the number and / or the substitution position of each of them are different and (2) R ¹ is the same as each other (hereinafter, General formula (V
It is a mixture of I). ) Get. This is reduced using a reducing agent such as sodium borohydride to obtain a mixture of cyclohexaneethanol derivatives. This is made into a mixture of (2-bromoethyl) cyclohexane derivatives with a brominating agent such as phosphorus tribromide and then reacted with triphenylphosphine to obtain a phosphonium salt. By using this as a Wittig reaction agent with a strong base, the alkylidenecyclohexane derivative obtained by reacting with the mixture of the above-mentioned general formula (III) is hydrogenated by catalytic reduction, and if necessary, by separating and removing the cis isomer, A mixture of general formula (Ia) can be obtained.

Alternatively, the intermediate (2-bromoethyl) cyclohexane derivative is reacted with magnesium to give a Grignard reagent, which is then reacted with the mixture of the general formula (III), dehydrated with an acid and then hydrogenated. You may. In this case, at least one of X ⁵ to X ⁸ is a hydrogen atom. (Production method b)

[0067]

Embedded image

(Wherein X ⁵ , X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² and Z have the same meanings as in formula (I).) A mixture of formula (III) is represented by formula (III) By reacting with a compound of IV), acid treatment and isomerization with a base, two or more compounds represented by the general formula (VII) are converted to (1)
The number and / or substitution position of deuterium atoms (D) in X ^{5 to} X ⁸ are different from each other, and (2) Y ¹ , Y ² and Z are mutually different.
Are the same, the above general formula (VII)
Of cyclohexanecarbaldehyde derivative represented by
A mixture of at least one species (hereinafter referred to as a mixture of general formula (VII)) is obtained.

[0069]

[Chemical 15]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² and Z have the same meanings as in formula (I). ) Next, the mixture of the above-mentioned general formula (V) is converted into a cyclohexanemethanol derivative with a reducing agent such as sodium borohydride, and from this, a Wittig reaction agent is obtained in the same manner as in (Production method a). This Wittig reagent has the general formula (VI
By reacting the mixture of I) and then hydrogenating, a mixture of general formula (Ia) can be obtained.

Alternatively, it is an intermediate (bromomethyl)
The cyclohexane derivative may be reacted with magnesium to give a Grignard reactant, which may be reacted with the mixture of the general formula (VII), dehydrated with an acid and then hydrogenated. (Production method c)

[0072]

Embedded image

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² and Z have the same meanings as in formula (I). ) A mixture of the general formula (VII) is converted into a cyclohexanemethanol derivative with a reducing agent such as sodium borohydride,
From this, a Wittig reaction agent is obtained in the same manner as in (Production method a). A mixture of the general formula (Ia) can be obtained by reacting the Wittig reactant with the mixture of the general formula (V) and then hydrogenating.

Alternatively, it is an intermediate (bromomethyl)
The cyclohexane derivative may be reacted with magnesium to give a Grignard reagent, which may be reacted with the mixture of the general formula (V), dehydrated with an acid and then hydrogenated. In this method, the trans-form cyclohexane ring is used. The above-mentioned production method is more preferable because a part thereof becomes a cis isomer during hydrogenation. (Production method d)

[0075]

[Chemical 17]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ , Y ² and Z have the same meanings as in formula (I). ) By reacting the mixture of the general formula (VII) with the compound of the formula (IV) again and treating with an acid, the compound of the general formula (VIII)
Two or more compounds represented in the, (1) together X ⁵ ~
Represented by the above general formula (VIII), wherein the number and / or substitution position of deuterium atoms (D) in X ⁸ are different, and (2) Y ¹ , Y ² and Z are the same as each other. A mixture of two or more cyclohexaneethanal derivatives (hereinafter referred to as the mixture of general formula (VIII)) is obtained. This is reduced using a reducing agent such as sodium borohydride to obtain a cyclohexaneethanol derivative. This is converted to a (2-bromoethyl) cyclohexane derivative with a brominating agent such as phosphorus tribromide and then reacted with triphenylphosphine to obtain a phosphonium salt. Using a strong base as a Wittig reaction agent, the compound of the general formula (II)
The mixture of general formula (Ia) can be obtained by hydrogenating the alkylidenecyclohexane derivative obtained by reacting with the mixture of 1 above by catalytic reduction and separating and removing the cis isomer as necessary.

Alternatively, an intermediate (2-bromoethyl) cyclohexane derivative is reacted with magnesium to give a Grignard reactant, which is then reacted with a mixture of the general formula (II), dehydrated with an acid and then hydrogenated. You may.

In each of the above-mentioned production methods, there is a case where Z in the general formula (Ia) is a group which is active under the reaction conditions, reactants and the like. In such a case, first, in the general formula (Ia), Z is a hydrogen atom.
It can be prepared by preparing a mixture of h) and then introducing the group into it.

[0079]

[Chemical 18]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ and Y ² have the same meanings as in formula (I). ) For example, when Z represents a cyano group, the compound represented by the general formula (Ia
It can be obtained by brominating or iodizing the mixture of h) and then reacting it with copper (I) cyanide.

[0081]

[Chemical 19]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ and Y ² have the same meanings as in formula (I). ) Alternatively, it can be obtained by reacting a mixture of the general formula (Iah) with oxalic acid dichloride in the presence of a Lewis acid such as aluminum chloride to form an acid chloride, which is converted to an acid amide with ammonia and then dehydrated with thionyl chloride or the like. it can.

[0083]

Embedded image

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ and Y ² have the same meanings as in formula (I). Alternatively, the mixture of the general formula (Iah) is reacted with acetyl chloride or acetic anhydride in the presence of a Lewis acid such as aluminum chloride to give an acetyl body, which is oxidized with bromine in an alkali to give a carboxylic acid. After being made into chloride, it can be obtained in the same manner as above.

[0085]

[Chemical 21]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ and Y ² have the same meanings as in formula (I), and W represents a leaving group such as chlorine atom, bromine atom, iodine atom or p-toluenesulfonyl group. . In the case where Z represents an alkenyl group, the bromide of the above intermediate is lithiated with alkyllithium such as butyllithium, which is then added in the presence of a copper (I) catalyst (LiCubl ₂ is preferred) or copper art. The complex can be obtained by reacting with an alkenyl halide or the like.

Particularly, in the general formula (Iah), Y ¹ = Y ²
In the case of ═fluorine atom, the mixture of the general formula (Iah) can be directly lithiated with butyllithium.

[0088]

[Chemical formula 22]

(Wherein R ¹ , X ¹ , X ² , X ³ , X ⁴ , X ⁵ ,
X ⁶ , X ⁷ , X ⁸ , Y ¹ and Y ² have the same meanings as in formula (I), and W has the same meaning as described above. When Z represents an alkenyloxy group, a mixture of Z in the general formula (Ia) in which OCH ₃ is demethylated (hydrobromic acid, boron tribromide, trimethylsilyl iodide, dimethyl sulfide / aluminum chloride). Etc. are used) to obtain a mixture of the general formula (Ioh) in which Z═OH, and this is used as an alcoholate in the presence of a base, and is alkenylated in the same manner as above.

By reacting the mixture of the general formula (Ioh) with BrCN in the presence of a base such as pyridine, a mixture of compounds of the general formula (I) in which Z is —OCN can be obtained.

In the above production method, the compound represented by the general formula (III)
In place of the deuterium-substituted general formula (I
II ')

[0092]

[Chemical formula 23]

By using the phenylcyclohexanone derivative represented by the formula (wherein Y ¹ , Y ² and Z have the same meanings as in formula (I)),
A mixture of b) can be obtained.

Similarly, in place of the general formula (II), the general formula (II ') not substituted by deuterium is used.

[0095]

[Chemical formula 24]

By using the compound represented by the formula (wherein R ¹ has the same meaning as in formula (I)), a mixture of formula (Ic) can be obtained. Each mixture of the general formula (II) or (III) used as a starting material in the above-mentioned production method contains the corresponding compound of the general formula (II ′) or (III ′) which is not deuterated in the presence of a base. Further, it can be obtained by substituting deuterium with D ₂ O. The reaction solvent is preferably an aprotic solvent such as dichloromethane, and the base is preferably an alkali metal alcoholate. In addition, 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.

Examples of the mixture of the general formula (Ia), the mixture of the general formula (Ib) and the mixture of the general formula (Ic) thus obtained are listed in Table 1 together with their phase transition temperatures.

[0098]

[Table 1]

(In the table, C represents a crystalline phase, N represents a nematic phase, and I represents an isotropic liquid phase.) The mixture of the general formula (I) of the present invention is substituted with the corresponding deuterium. The melting point is clearly lower than that of the compound without it.
Moreover, it has a feature that crystals are hard to precipitate at low temperature.

As an example, a low-viscosity host liquid crystal (H) for active matrix

[0101]

[Chemical 25]

A mixed liquid crystal (M-3) consisting of 70% by weight and 30% by weight of the mixture of (No. 3) in Table 1 was prepared. Further, for comparison, the compound of formula (R-3) which has 70% by weight of host liquid crystal (H) and a similar structure of (No. 3), but is not deuterium-substituted.

[0103]

[Chemical formula 26]

A mixed liquid crystal (M
R-3) was prepared. These mixed liquid crystals are cooled to room temperature (about 25
When left at (° C.), no crystal precipitation could be observed in (M-3) even if left for 1 week. On the other hand, (MR
In 3), precipitation of a trace amount of crystals was observed after 3 days. Next, when these mixed liquid crystals were stored at −20 ° C., they were crystallized together in one week, but when their melting points were measured thereafter, it was 26 ° C. in (M-3), whereas
R-3) was as high as 30 ° C.

Next, a mixed liquid crystal (M-1) comprising 70% by weight of the host liquid crystal (H) and 30% by weight of the mixture of (No. 1) in Table 1 was prepared, and the host liquid crystal (M-1) was prepared for comparison. H) 70% by weight and a similar structure of (No. 1) but without deuterium substitution of formula (R-1)

[0106]

[Chemical 27]

A mixed liquid crystal (M
R-1) was prepared. These mixed liquid crystals are cooled to room temperature (about 25
When left for 1 week, no precipitation of crystals was observed. However, when these mixed liquid crystals were stored at −20 ° C. and crystallized and then their melting points were measured, it was 7 ° C. in (M-1), while it was 12 in (MR-3). It was as high as ℃.

From this, it can be understood that the mixture of the general formula (I) according to the present invention has a low melting point, is difficult to crystallize at low temperature, and is extremely useful as a practical liquid crystal material.

[0109]

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 to show the same retention time (or Rf value), and the nuclear magnetic resonance It was confirmed by spectrum (NMR), mass spectrum (MS) and infrared absorption spectrum (IR). The D conversion of the mixture was measured by NMR. The NMR used for the measurement was JNM-GSX400 (400 MHz ¹ manufactured by JEOL Ltd.).
H). The D conversion rate of the mixture of the general formula (I) is the same as the general formula (II) or the general formula (II
The D conversion rate of the mixture of I) was used as it was.

In the structural formula, in ring D, at least one hydrogen atom (H) of the cyclohexane or cyclohexanone ring is replaced with a deuterium atom (D) (D is a group represented by the general formula (I), ( II), (III), etc., are substituted at the positions shown by X ^{1 to} X ⁸ ), and d ₄ − described in the compound name is a hydrogen atom at the above position of the cyclohexane ring. X ^{1 to} X ⁴ or X ^{5 to} X ⁸
In the above, a mixture of up to 4 deuterium-substituted compounds is represented. Further, "%" in the composition represents "% by weight".

[0112] (Reference Example 1) Synthesis of d _{4-4-propyl-cyclohexanone}

[0113]

[Chemical 28]

24 g of sodium methoxide was dissolved in 160 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 to give the cyclohexanone ring 2
Position and / or 6-position to obtain a d _{4-4-propyl-cyclohexanone} 180g which is deuterated. 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 85%.

[0116] In Reference Example 2 Reference Example 1 d _4-4-butyl cyclohexanone, instead of 4-propyl cyclohexanone, except using 4-butyl-cyclohexanone in the same manner as in Reference Example 1, d ₄ - 4-Butylcyclohexanone was obtained. When the D conversion rate was measured by NMR, it was about 8
It was 8%.

Reference Example 3 Synthesis of d ₄ -4- (3,4-difluorophenyl) cyclohexanone

[0118]

[Chemical 29]

14.0 g of sodium methoxide was dissolved in 44 g of heavy water (D conversion rate 99.8%). 4- (3,4-difluorophenyl) cyclohexanone dissolved in 180 ml of dichloromethane (this compound is a Grignard reaction agent prepared from 1-bromo-3,4-difluorobenzene is cyclohexane-1,4-dione monoethylene acetal). It was reacted with, dehydrated, and then hydrogenated the cyclohexene ring, and then deacetalized.) 105 g was added, and further tetrabutylammonium bromide 2.0 g was added, and the mixture was heated with stirring at the reflux temperature of the solvent for 6 hours. did. 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 dried over anhydrous sodium sulfate.

By distilling off the solvent, the cyclohexanone ring 2
D ₄ -4- (3 to position and / or 6-position is deuterated,
106 g of 4-difluorophenyl) cyclohexanone 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 65%.

Reference Example 4 d ₄ -4- (3,4,5-
Synthesis of trifluorophenyl) cyclohexanone Referential Example 3 except that 4- (3,4,5-trifluorophenyl) cyclohexanone was used in place of 4- (3,4-difluorophenyl) cyclohexanone in Reference Example 3. It was obtained in the same manner d ₄ -4- (3,4,5- trifluorophenyl) cyclohexanone. When the D conversion rate was measured by NMR, it was about 70%.

[0122] In (Example 5) d _{4-4-(4-fluorophenyl)} Reference Example 3 of cyclohexanone, instead of 4- (3,4-difluorophenyl) cyclohexanone, 4- (4-fluorophenyl) except for using cyclohexanone in the same manner as in reference example 3 to give the d ₄ -4- (4- fluorophenyl) cyclohexanone. When the D conversion rate was measured by NMR, it was about 65%.

[0123] In (Example 6) d _{4-4-(4-chlorophenyl)} Reference Example 3 of cyclohexanone, instead of 4- (3,4-difluorophenyl) cyclohexanone, 4- (4-chlorophenyl) cyclohexanone except for using in the same manner as in reference example 3 to give the d ₄ -4- (4- chlorophenyl) cyclohexanone. When the D conversion rate was measured by NMR, it was about 70%.

[0124] In (Example 7) d _{4-4-Referential} Example 3 of phenyl cyclohexanone, instead of 4- (3,4-difluorophenyl) cyclohexanone, except for using 4-phenyl cyclohexanone Reference Example 3 Similarly, d ₄ −
4-phenylcyclohexanone was obtained. When the D conversion rate was measured by NMR, it was about 68%.

Reference Example 8 d ₄ -trans-4-
Synthesis of (3,4,5-trifluorophenyl) cyclohexanecarbaldehyde

[0126]

[Chemical 30]

248 g of methoxymethyltriphenylphosphonium chloride was added to 250 m of tetrahydrofuran (THF).
1 and 750 ml of toluene and suspended in ice. To this, 81.2 g of potassium t-butoxide was added in two batches so that the internal temperature did not exceed 5 ° C. to prepare a Wittig reaction agent. After stirring for 1 hour, 129 g of d ₄ -trans-4- (3,4,5-trifluorophenyl) cyclohexanone obtained in Reference Example 4 was added with 100 ml of toluene and TH.
It was dissolved in 400 ml of F and added dropwise at an internal temperature of 10 ° C or lower.
After stirring for another 1 hour, 1000 ml of water was added, and the mixture was neutralized with a small amount of dilute hydrochloric acid. The organic layer was concentrated under reduced pressure, 1200 ml of hexane was added, and the precipitated crystals were separated by filtration. The filtrate was washed with a water / methanol mixed solvent and the solvent was distilled off to obtain 172 g of an enol ether compound as an intermediate. The whole amount was dissolved in 650 ml of THF, 200 ml of dilute hydrochloric acid was added, and the mixture was heated under reflux for 1 hour. After cooling, the mixture was extracted with ethyl acetate, dehydrated and the solvent was distilled off. It was dissolved in 560 ml of methanol, 28 ml of a 20% aqueous sodium hydroxide solution was added dropwise, and the mixture was stirred for 2 hours. After adding 200 ml of water and extracting with toluene, the organic layer was washed with water and the solvent was distilled off under reduced pressure to give 143 g of d ₄ -trans-4- (3,4,5-trifluorophenyl) cyclohexanecarbaldehyde. Got

Reference Example 9 d ₄ -trans-4-
(3,4-difluorophenyl) d _{4-4-(3,4-difluorophenyl)} obtained in Reference Example 3 of cyclohexane carbaldehyde analogously from cyclohexanone as in Reference Example 8,
d ₄ -trans-4- (3,4-difluorophenyl)
Cyclohexanecarbaldehyde was obtained.

Reference Example 10 d ₄ -trans-4-
(4-fluorophenyl) by the d _{4-4-(4-fluorophenyl)} cyclohexanone obtained in Reference Example 5 cyclohexane carbaldehyde in the same manner as in Reference Example 8, d ₄
-Trans-4- (4-fluorophenyl) cyclohexanecarbaldehyde was obtained.

Reference Example 11 d ₄ -trans-4-
D _4-4-obtained in Reference Example 6 (4-chlorophenyl) cyclohexane carbaldehyde (4-chlorophenyl)
D ₄ -trans-4- (4-chlorophenyl) cyclohexanecarbaldehyde was obtained from cyclohexanone in the same manner as in Reference Example 8.

Reference Example 12 Synthesis of d ₄ -trans- ₄ -phenylcyclohexanecarbaldehyde From d 4-4-phenylcyclohexanone obtained in Reference Example 7, d ₄ -trans-4 was prepared in the same manner as in Reference Example 8. -Phenylcyclohexanecarbaldehyde was obtained.

Reference Example 13 Synthesis of d ₄ -trans-1-bromomethyl-4-propylcyclohexane

[0133]

[Chemical 31]

30.9 g of methoxymethyltriphenylphosphonium chloride was dissolved in 120 ml of THF and cooled to 5 ° C. To this, 10.9 g of potassium t-butoxide was added and stirred at the same temperature for 1 hour to prepare a Wittig reaction agent. To this was added dropwise to dissolve the d _{4-4-propyl-cyclohexanone} 10.3g obtained in Reference Example 1 in 20 ml of THF, and stirred for 1 hour at the same temperature. 80 ml of water was added and further neutralized with a small amount of dilute hydrochloric acid. The organic layer was concentrated under reduced pressure, 150 ml of hexane was added, and the precipitated crystals were separated by filtration. The filtrate was washed with a water / methanol mixed solvent and the solvent was distilled off to obtain 11.9 g of an enol ether compound as an intermediate. The whole amount was dissolved in 50 ml of THF, 10 ml of 10% hydrochloric acid was added, and the mixture was stirred at room temperature for 5 hours. Hexane and water were added, and after liquid separation, the aqueous layer was extracted with hexane, the organic layers were combined and dehydrated and dried, and then the solvent was distilled off. 11.6 g of the obtained crude crystals were added to 11 ml of ethanol and 8
Dissolve in 5 ml, 1 ml of 20% aqueous sodium hydroxide solution
And 10 ml of water were added dropwise, and the mixture was stirred for 2 hours. 100m of water
1 was added and the mixture was extracted with hexane, the organic layer was washed with water, and the solvent was distilled off under reduced pressure to obtain 11.5 g of d ₄ -trans-4-propylcyclohexanecarbaldehyde.

All of this was dissolved in 50 ml of ethanol,
This was added dropwise to a 15 ml ethanol solution of 1.3 g of sodium borohydride at 5 ° C. After stirring for 2 hours, excess hydride was decomposed by adding water and dilute hydrochloric acid. After distilling off most of the ethanol under reduced pressure, d ₄ and extracted with toluene - was obtained trans-4-propyl-cyclohexane methanol 10.5 g.

The whole amount was dissolved in hexane (ml) and cooled to 5 ° C. 21.3 g of phosphorus tribromide was added dropwise thereto over 30 minutes, and the mixture was further stirred for 1 hour. After water was added to decompose excess phosphorus tribromide, the organic layer was separated. After dehydration and drying,
The solvent is distilled off, and further distilled under reduced pressure (92 to 95 ° C / 4m
mHg) to, d ₄ - trans-1-bromomethyl -4
9.9 g of -propylcyclohexane were obtained.

Reference Example 14 Bromide (d ₄ -trans-)
Synthesis of 4-propylcyclohexylmethyl) triphenylphosphonium

[0138]

[Chemical 32]

[0139] Triphenylphosphine 287g of toluene 70ml solution in Reference Example 13 obtained in d ₄ - trans-1-bromomethyl-4-propyl cyclohexane 20
0 g was added, and the mixture was heated under reflux for 8 hours. Toluene was distilled off under reduced pressure, 200 ml of THF was added, and the mixture was further heated and refluxed for 2 hours. The mixture was allowed to cool to room temperature, the precipitated crystals were separated by filtration, and dried under reduced pressure to obtain 233 g of (d ₄ -trans-4-propylcyclohexylmethyl) triphenylphosphonium bromide crystals.

(Example 1) 1- [d ₄ -transformer-4
Synthesis of-[2- (trans-4-propylcyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluorobenzene (mixture of No. 1 in Table 1)

[0141]

[Chemical 33]

223 g of (d ₄ -trans-4-propylcyclohexylmethyl) triphenylphosphonium bromide obtained in Reference Example 14 was added to 600 ml of toluene and THF.
It was dissolved in 200 ml and cooled to -20 ° C. 52.0 g of potassium t-butoxide was added in two portions over 30 minutes,
Further, the mixture was stirred at -20 ° C for 1 hour to prepare a Wittig reaction agent. In addition, d ₄ -trans-4 obtained in Reference Example 8
A solution of 95.1 g of-(3,4,5-trifluorophenyl) cyclohexanecarbaldehyde in 200 ml of toluene was added dropwise over 30 minutes. The temperature was raised to room temperature and further stirred for 1 hour. After 800 ml of water was added and the mixture was neutralized with diluted hydrochloric acid, it was extracted twice with 500 ml of toluene. The organic layers were combined and dehydrated and dried over anhydrous sodium sulfate. Toluene was distilled off under reduced pressure, 1000 ml of hexane was added, and the precipitated crystals of triphenylphosphine oxide were filtered off. The filtrate was concentrated again and then purified using column chromatography to give 1- [d ₄ -trans-4- [2- (trans-4.
-Propylcyclohexyl) ethenyl] cyclohexyl] -3,4,5-trifluorobenzene crystals 131
g was obtained. Dissolve the whole amount in 500 ml of ethyl acetate,
13% of 5% palladium carbon was added, and hydrogen pressure was 4 Kg / cm.
Stirred at ² for 8 hours at room temperature. The catalyst was filtered through diatomaceous earth, and the crude crystals obtained by concentrating the filtrate were recrystallized from a hexane / ethanol mixed solvent (1/10) to give 1- [d ₄ -trans-4- [2- (trans- 93.8 g of crystals of 4-propylcyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluorobenzene were obtained. The melting point of this mixture was 44 ° C., and upon cooling from the isotropic liquid (I) phase, a phase transition was made to a nematic (N) phase at 83 ° C.

Comparative Example 1 1- [trans-4- [2
-(Trans-4-propylcyclohexyl) ethyl]
Synthesis Example 1 of cyclohexyl] -3,4,5-trifluoro-benzene (compound of formula (R-1)), d 4 - trans-4- (3,4,5
-Trifluorophenyl) cyclohexanecarbaldehyde instead of deuterium-substituted trans-4-
In the same manner as in Example 1 except that (3,4,5-trifluorophenyl) cyclohexanecarbaldehyde was used,
1- [trans-4- [2- (trans-4-propylcyclohexyl) ethyl] cyclohexyl] -3,4
5-Trifluorobenzene was obtained. The melting point of this compound was as high as 49 ° C., and the N phase upper limit temperature was 83.5 ° C.

(Example 2) 1- [d ₄ -trans-4
- Synthesis Example 1 - [2- (d ₄ trans-4-propyl cyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluoro-benzene (No.2 mixture in Table 1), bromide instead of (trans-4-propyl-cyclohexyl methyl) triphenylphosphonium bromide obtained in reference example 14 (d ₄ - trans-4-
1- [d ₄ was obtained in the same manner as in Example 1 except that propylcyclohexylmethyl) triphenylphosphonium was used.
- trans -4- [2- (d ₄ - trans-4-propyl-cyclohexyl) ethyl] cyclohexyl] -3,
4,5-Trifluorobenzene was obtained. The phase transition temperatures of this mixture are summarized in Table 1.

(Example 3) 1- [d ₄ -trans-4
Synthesis of-[2- (trans-4-ethylcyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluorobenzene (mixture of No. 3 in Table 1) In Example 1, bromide (trans- Example 1 except that (trans-4-ethylcyclohexylmethyl) triphenylphosphonium bromide was used instead of 4-propylcyclohexylmethyl) triphenylphosphonium.
In the same manner as in 1- [d ₄ -trans-4- [2- (trans-4-ethylcyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluorobenzene was obtained.
The phase transition temperatures of this mixture are summarized in Table 1.

(Example 4) 1- [d ₄ -trans-4
- Synthesis of - [2-(d ₄ trans-4-propyl cyclohexyl) ethyl] cyclohexyl] -3,4-difluorobenzene (mixture No.4 in Table 1)

[0147]

Embedded image

In Example 1, d ₄ -trans-4-
In place of (3,4,5-trifluorophenyl) cyclohexane carbaldehyde, d ₄ obtained in Reference Example 9 - using trans-4- (3,4-difluorophenyl) cyclohexane carbaldehyde, bromide (trans In the same manner as in Example 1 except that (d ₄ -trans-4-propylcyclohexylmethyl) triphenylphosphonium bromide obtained in Reference Example 14 was used instead of -4-propylcyclohexylmethyl) triphenylphosphonium. 1
- [d ₄ - trans -4- [2- (d ₄ - trans-4-
Propylcyclohexyl) ethyl] cyclohexyl]-
3,4-difluorobenzene was obtained. The phase transition temperatures of this mixture are summarized in Table 1.

(Example 5) 1- [trans-4- [2
- Synthesis Example 1 - (trans-4-butylcyclohexyl d ₄₎ ethyl] cyclohexyl] -3,4-difluorobenzene (a mixture of No.5 in Table 1), d ₄ - trans-4- ( 3,4,5
-Trifluorophenyl) cyclohexanecarbaldehyde, trans-4- (3,4-difluorophenyl) cyclohexanecarbaldehyde was used, and (trans-4-propylcyclohexylmethyl) triphenylphosphonium bromide was used. (D ₄ -transformer-4
-Butylcyclohexylmethyl) triphenylphosphonium was used in the same manner as in Example 1, except that 1
- [trans-4- [2-(d ₄ - trans-4-butylcyclohexyl) ethyl] cyclohexyl] 3,4
-Difluorobenzene was obtained. The phase transition temperatures of this mixture are summarized in Table 1.

(Example 6) 1- [d ₄ -trans-4
- Synthesis Example 1 [2- [trans-4- (3-methoxypropyl) cyclohexyl] ethyl] cyclohexyl] -3,4-difluorobenzene (No.6 mixture in Table 1), d ₄ - Trans-4- (3,4,5
- instead of trifluorophenyl) cyclohexane carbaldehyde, d ₄ - using trans-4- (3,4-difluorophenyl) cyclohexane carbaldehyde, bromide (trans-4-propyl-cyclohexyl methyl) in place of triphenylphosphonium , Bromide [trans-4
- (3-methoxypropyl) except for using cyclohexyl methyl] mixture of triphenylphosphonium in the same manner as in Example 1, 1- [d ₄ - trans-4- [2-
[Trans-4- (3-methoxypropyl) cyclohexyl] ethyl] cyclohexyl] -3,4-difluorobenzene was obtained. The phase transition temperatures of this mixture are summarized in Table 1.

Example 7 1- [d ₄ -transformer-4
-[2- (trans-4-propylcyclohexyl) ethyl] cyclohexyl] -4-fluorobenzene (first
No. in the table Synthesis Example 1 of 7 mixture), d ₄ - trans-4- (3,4,5
1- [d ₄ -trans-4 in the same manner as in Example 1 except that d ₄ -trans-4- (4-fluorophenyl) cyclohexanecarbaldehyde was used instead of -trifluorophenyl) cyclohexanecarbaldehyde. -[2
-(Trans-4-propylcyclohexyl) ethyl]
Cyclohexyl] -4-fluorobenzene was obtained. The phase transition temperatures of this mixture are summarized in Table 1.

(Embodiment 8) 1- [d ₄ -transformer-4
- Synthesis Example 1 [2- (trans-4-propyl cyclohexyl) ethyl] cyclohexyl] -4- chlorobenzene (No.8 mixture in Table 1), d ₄ - trans-4- (3,4 , 5
1- [d ₄ -trans-4-, except that d ₄ -trans-4- (4-chlorophenyl) cyclohexanecarbaldehyde was used instead of -trifluorophenyl) cyclohexanecarbaldehyde. [2-
(Trans-4-propylcyclohexyl) ethyl] cyclohexyl] -4-chlorobenzene was obtained. The phase transition temperatures of this mixture are summarized in Table 1.

(Example 9) 1- [d ₄ -trans-4
Synthesis of-[2- (trans-4-propylcyclohexyl) ethyl] cyclohexyl] -4-cyanobenzene (mixture of No. 9 in Table 1)

[0154]

Embedded image

In Example 1, d ₄ -trans-4-
Substituting a mixture of (3,4,5-trifluorophenyl) cyclohexanecarbaldehyde for d ₄ -trans-4
[D ₄ -trans-4 was prepared in the same manner as in Example 1 except that a mixture of phenylcyclohexanecarbaldehyde was used.
-[2- (trans-4-propylcyclohexyl) ethyl] cyclohexyl] benzene was obtained.

20 g of this mixture are added to 80 g of dichloromethane.
Dissolve in ml, add 12 g of anhydrous aluminum chloride and add ice
Cooled down. Oxalic acid dichloride dissolved in 40 ml of dichloromethane
Be careful not to let the internal temperature exceed 10 ° C for 9.5 g of chloride.
Was dropped. After stirring under ice-cooling for 2 hours, dilute with hydrochloric acid and ice.
It was opened and extracted with dichloromethane. This dichloromethane
The solution was added to 200 ml of 30% ammonia water under ice cooling at 10 ° C or higher.
Dropped down. After stirring for 1 hour at 5-10 ° C,
The separated crystals were collected by filtration, dried under reduced pressure and treated with 4- [d _Four− Tiger
Ns-4- [2- (trans-4-propylcyclohexyl
Crude crystals of sil) ethyl] cyclohexyl] benzamide
12 g was obtained.

The total amount of the obtained benzamide mixture was dissolved in 50 ml of toluene, 20 ml of thionyl chloride was added, and the mixture was heated and stirred under reflux for 1 hour. After allowing to cool, water was added and the mixture was stirred, and the organic layer was separated. The aqueous layer was extracted with toluene, the organic layers were combined, washed with water, and dried over anhydrous sodium sulfate. The crude product obtained by distilling off the solvent was purified by silica gel column chromatography (toluene) and further recrystallized from methanol to give 1- [d ₄ -trans-
4- [2- (trans-4-propylcyclohexyl)
4.8 g of crude crystals of ethyl] cyclohexyl] -4-cyanobenzene were obtained. The phase transition temperatures of this mixture are summarized in Table 1.

Example 10 Preparation of Liquid Crystal Composition (1)

[0159]

Embedded image

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

70% of this host liquid crystal (H) and Example 1
A liquid crystal composition (M-1) consisting of 30% of the mixture of (No. 1) obtained in 1. was prepared. The T _{NI of} this composition is 10
5 ° C. This composition (M-1) was stored at 0 ° C. and room temperature (about 20 ° C.) for 1 week, but neither crystal precipitation was observed. Moreover, this composition (M-3) was -25
When it was stored at ℃, it crystallized, but when the melting point was measured thereafter, it was 7 ℃.

(Comparative Example 2) 70% of host liquid crystal (H) and the formula (R-1) obtained in Comparative Example 1

[0163]

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A liquid crystal composition (MR-1) containing 30% of 1- [trans-4- [2- (trans-4-propylcyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluorobenzene was prepared. did. T of this composition
_NI was 105.5 ° C. and (M-1), which was almost unchanged. This composition (MR-1) was added at 0 ° C. and room temperature (about 20 ° C.).
When stored at 0 ° C), there was no change at room temperature, but 0
Precipitation of crystals was observed at 1 ° C in 1 week. On the other hand, when this composition was stored at −25 ° C., it also crystallized,
When the melting point was measured thereafter, it was 12 ° C., which was higher than (M-1).

Example 11 Preparation of Liquid Crystal Composition (2) 70% of host liquid crystal (H) and Example 3 (N) were obtained.
o. Liquid crystal composition (M-3) comprising 30% of the mixture of 3)
Was prepared. The T _{NI of} this composition was 95.5 ° C. This composition (M-3) was stored at room temperature (about 20 ° C.) for 1 week, but no crystal precipitation was observed. On the other hand, when this composition (M-3) was stored at -25 ° C, it was crystallized, but its melting point was measured to be 26 ° C.

(Comparative Example 3) Host liquid crystal (H) 70% and formula (R-3)

[0167]

[Chemical 38]

A liquid crystal composition (MR-3) containing 30% of 1- [trans-4- [2- (trans-4-ethylcyclohexyl) ethyl] cyclohexyl] -3,4,5-trifluorobenzene was prepared. did. T of this composition
_NI showed almost no change from 96 ° C to (M-3).
When this composition (MR-3) was stored at room temperature (about 20 ° C.), precipitation of a trace amount of crystals was observed within one week.
On the other hand, when this composition was stored at −25 ° C., it also crystallized, but the melting point was measured at 30 ° C. (M
It was higher than -1).

Therefore, it is clear that the deuterium-substituted mixture of the general formula (I) of the present invention lowers the melting point of the liquid crystal composition with almost no change in the T _NI of the liquid crystal composition. A liquid crystal composition having a wider phase temperature range can be obtained. It is also clear that it has the effect of making crystals less likely to precipitate at lower temperatures.

[0170]

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 which 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 a 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.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 43/225 C 7419-4H 255/50 261/00 9451-4H C09K 19/42 G02F 1/13 500 // C07M 5:00

Claims (10)

[Claims] 1. A compound represented by the general formula (I):(In the formula, R¹Is an alkyl group having 1 to 12 carbon atoms or
Represents a lucoxyalkyl group, X¹, X², X³, X^Four, X
^Five, X⁶, X⁷And X⁸Are each independently a hydrogen atom (H)
Or represents a deuterium atom (D), and Y¹And Y²Are each
Independently represents a hydrogen atom or a fluorine atom, and Z is fluorine
Atom, chlorine atom, hydrogen 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 3 to 12 carbon atoms.
The cyclohexane ring is in the trans configuration. )
Two or more compounds to be given are (1) X¹~ X⁸To
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), R¹Is a carbon atom
Linear alkyl group or alkoxyalkyl group of formula 1 to 7
Represents, Z is a fluorine atom, a chlorine atom, a cyano group, carbon
Linear alkyl group or alkoxyl having 1 to 7 atoms
Group, -OCF ₃Or -OCH₂CF₃Characterized by
The mixture according to claim 1, wherein 3. In the general formula (I), Y ¹ , Y ² and Z
The mixture according to claim 2, wherein at least one of them is a fluorine atom. 4. The mixture according to claim 3, wherein in the general formula (I), Z and Y ¹ are both fluorine atoms. 5. The mixture according to claim 2, wherein in the general formula (I), Y ¹ and Y ² are both hydrogen atoms. 6. The mixture according to claim 5, wherein Z in the general formula (I) is a chlorine atom or a cyano group. 7. The mixture according to claim 6, wherein in the general formula (I), R ¹ is a linear alkyl group having 1 to 7 carbon atoms. 8. In the general formula (I), X ¹ , X ² , X ³
8. The mixture according to claim 3, wherein X and X ⁴ are all hydrogen atoms (H). 9. In the general formula (I), X ⁵ , X ⁶ , X ⁷
And X ⁸ are all hydrogen atoms (H). 10. Deuterium based on the total number of X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ , X ⁷ and X ⁸ in two or more compounds represented by general formula (I). 10. The mixture according to claim 1, wherein the proportion of the number of atoms (D) is in the range of 20 to 95%.