JPH0710784A - Phenylcyclohexane derivative - Google Patents

Abstract

PURPOSE:To obtain a mixture consisting of new phenylcyclohexane derivatives and capable of providing a liquid crystal composition not depositing crystals for a long period in low-temperature area without reducing electrooptical characteristics of a liquid crystal material. CONSTITUTION:The objective mixture is composed of two or more kinds of compounds of formula I (R<1> is 1-12C alkyl; X<1> to X<3> are H or deuterium and at least one of X<1> to X<3> is deuterium; Y<1> and Y<2> are H or F; Z is F, Cl, etc.; R<2> is 1-12C alkyl or 2-12C alkenyl; cyclohexane ring has trans configuration) and mutually different in number of deuterium and/or replaced positions and being mutually same in R<1>, Y<1>, Y<2> and Z. This mixture is obtained by reacting, e.g. a compound of formula II with Mg, reacting a mixture of the reactional product with a compound of formula III to afford a compound of formula IV, dehydrating this compound, hydrogenating the dehydrated compound and further, as necessary, carrying out isomerization to trans body and then separating and removing cis isomer. Furthermore, the compound of formula II is a new substance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixture of liquid crystal compounds having a deuterium atom, which can improve the characteristics of an electro-optical liquid crystal display material, and more particularly, to an electro-optical liquid crystal material which is widely used. Properties, that is, nematic phase-isotropic liquid phase transition temperature, threshold voltage, refractive index anisotropy, dielectric anisotropy, response speed, etc.
The present invention relates to a mixture of phenylcyclohexane derivatives having an excellent effect of preventing crystals from precipitating in a low temperature region for a long period of time, and further relates to a mixture of cyclohexanone derivatives useful as a production intermediate of this mixture.

[0002]

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

Various characteristics are required as a liquid crystal material according to these display system and drive system. (1)
The wide temperature range of the liquid crystal phase and (2) the small viscosity are important required characteristics common to all the methods. More specifically, as the characteristics of (1), it is important that (1a) the nematic phase maximum temperature (T _NI ) is high, and (1b) that the melting point is low so that phase separation such as crystallization or precipitation does not easily occur. .

Up to the present, no liquid crystal compound which alone satisfies such required properties has been known, and it is actually used as a mixture of various liquid crystal compounds. Among them, in order to obtain a liquid crystal material 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 such a method is used, for example, when the nematic phase-isotropic liquid phase transition temperature (hereinafter referred to as T _NI point) of the liquid crystal material is increased, the mixing ratio of the liquid crystal compound having a high T _NI point is set. It should be high. However, such compounds are minimum temperature of liquid crystal phases so (hereinafter, referred to. T _CN point) is high, will be risen T _CN point inevitably resulting liquid crystal composition,
In many cases, crystals are precipitated at a low temperature, and in many cases it cannot be used as a practical liquid crystal material.

From the above, when preparing a practical liquid crystal material 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 exhibited. The temperature range of the liquid crystal phase is expanded by empirically mixing 10 to 20 kinds of liquid crystal compounds and compounds 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 according to the purpose of use, and therefore, the liquid crystal compound as the constituent component of the liquid crystal material may be another compound. It cannot be used unless it satisfies various required properties to some extent, including compatibility with. Therefore, among many liquid crystal compounds, the selection range of compounds that can be used in preparing a practical liquid crystal material is considerably limited.

For example, in addition to the characteristics (1) and (2) described above, the liquid crystal material used for STN-LCD has
(3) The elastic constant ratio (K ₃₃ / K ₁₁ ) of the liquid crystal material is large,
Achieving high contrast is required. Furthermore, since the STN display system is often applied to general-purpose devices such as laptop computers, low threshold voltage is also an important required characteristic.

In order to lower the threshold voltage of the liquid crystal material, the dielectric anisotropy Δε of the liquid crystal material is calculated according to the following formula.
Or increasing the elastic constant K is effective.

[0009]

[Equation 1]

(Wherein V _th is a threshold voltage, k is a proportional constant, K is an elastic constant, and Δε is a dielectric anisotropy.) Here, as a liquid crystal compound having a very large Δε, for example, , There are compounds such as the following formulas, but if a large amount of a compound with too large Δε is used, problems such as increase in current value often occur, and when actually used as a liquid crystal display device, in terms of reliability. There's a problem.

[0011]

[Chemical 4]

(In the formula, R represents an alkyl group.) Further, the liquid crystal material having a small elastic constant is a liquid crystal compound having a proper Δε value (hereinafter referred to as a p-type liquid crystal compound).
And maternal consisting, T _NI point is high, and relatively small third liquid crystal compound ring system Δε have a negative suitable value of elastic constant (hereinafter referred to as n-type liquid crystal compound.) Or p-type liquid crystal compound It is prepared by the method of mixing.

Further, as the p-type liquid crystal compound having a large elastic constant ratio K ₃₃ / K ₁₁ required for achieving high contrast, for example, the following compounds are used.

[0014]

[Chemical 5]

(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, Although it is necessary to mix such a p-type liquid crystal compound and a tricyclic liquid crystal compound, there is a problem that crystals tend to be precipitated in a low temperature region. Therefore, they have the same skeleton and R '
Of the above p-type liquid crystal are added by adding many kinds of homologues having different carbon atoms from each other, or when R'is alkenyl, adding many kinds of homologues having different double bond positions from each other. _Has lowered the T _CN point.

However, in such a method, due to the difference in the number of carbon atoms or the position of the double bond,
Elastic constant ratio because K ₃₃ / K ₁₁ are different values of the compound, after all, the elastic constant ratio K ₃₃ / K ₁₁ of the resulting liquid crystal material is reduced, often contrast 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.

At present, a liquid crystal composition for STN having a low threshold voltage of about 1.2 V is prepared, but the elastic constant ratio K ₃₃ / K ₁₁ is sufficient as described above. Since it is not large and the T _CN point is not low, an STN-LCD having a low driving voltage, high contrast and usable even in a low temperature region has not yet been manufactured.

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. Is limited. In particular,
Many general-purpose liquid crystal materials are designed with a focus on satisfying the electro-optical characteristics, but the temperature range of the liquid crystal phase of (1) is sufficiently low, especially in the low temperature range, and is practically used. Few things are reliable.

Therefore, a liquid crystal display device using a liquid crystal material which is widely used at present and which substantially satisfies the above-mentioned characteristics (2) and (3), can be formed by the liquid crystal material unless the problem of crystal precipitation at a low temperature is solved. The operating environment temperature is limited.

Under these circumstances, there has been a demand for a compound which can further lower the T _CN point without reducing the electro-optical characteristics of liquid crystal materials or liquid crystal display devices currently used.

[0021] Generally, since T _CN point of the liquid crystal material is often mixed system composition comprised of individual liquid crystal simple substance exhibits supercooling phenomenon, usually T _CN point the liquid crystal material in a liquid nitrogen or the like Sufficiently low temperature for solidification or glass state (eg -70
The temperature is gradually increased to measure the transition temperature from the solid to the nematic phase, and this is taken as the T _CN point.

However, in the case of a practical liquid crystal material having 10 to 20 kinds of components, since it is not a eutectic mixture, the lower limit temperature of the nematic phase based on the above measurement and the lower limit of the actually reversibly stable nematic phase are obtained. Even if the temperature does not match, and even if it is stored at a temperature higher than the lower limit temperature of the nematic phase based on the above-mentioned measurement, there are many cases where crystals will precipitate, and in the end, the operable temperature range is the temperature based on the above-mentioned measurement. It may be narrower than the 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, it is required that a nematic phase is stably exhibited in a wide temperature range from -40 ° C to 110 ° C for in-vehicle use, aircraft use, etc. For example, some crystals may be precipitated in about 1 week when stored at -25 ° C.

From such an example, the T _{CN of the} liquid crystal composition is also
Even if the point is very low, crystals do not always precipitate at higher temperatures. Therefore, in order to satisfy the characteristics of (1) above, crystals that do not precipitate even when stored at low temperature for a long time are required. To be done.

However, a liquid crystal material which is a highly reliable liquid crystal material in which crystals do not precipitate even if it is stored at a lower temperature for a long time and which sufficiently satisfies the electro-optical characteristics required for various display systems and drive systems. No material is currently available.

[0026]

The problems to be solved by the present invention include electro-optical characteristics of liquid crystal compositions used in various liquid crystal display devices, that is, a nematic phase-isotropic liquid phase transition temperature, The present invention provides a mixture that does not cause precipitation of crystals for a long period of time in a low temperature region without reducing the threshold voltage, response characteristics, etc., and can substantially extend the operable temperature range. To provide the body.

[0027]

In order to solve the above-mentioned problems, the present invention has the general formula (I)

[0028]

[Chemical 6]

(In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, and X ¹ , X ² and X ³ each independently represent a hydrogen atom (H) or a deuterium atom (D). But,
At least one represents a deuterium atom (D), Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom, and Z is a fluorine atom, a chlorine atom, a cyano group, —R ² ,
_{^{-OR 2, -CF 3, -OCF 3}} , -OCF 2 H, -OCN
Or represents -OCH ^₂ CF _3, R ₂ is -C 1-1
2 represents an alkyl group having 2 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms, and includes a fluorine atom, a chlorine atom, a cyano group, a linear alkoxyl group having 1 to 7 carbon atoms, and a carbon atom having 2 to 7 carbon atoms.
Alkenyloxy group, -OCF _3, -OCN or -O
CH ₂ CF ₃ is preferred and the cyclohexane ring is in the trans configuration. ), At least two compounds selected from the group consisting of compounds represented by the formula (1) are different from each other in (1) the number of deuterium atoms and / or the substitution position, and (2) R is mutually different.
^There is provided a mixture of two or more compounds selected from the group consisting of the compounds represented by the general formula (I), wherein ¹ , ¹ , Y ² , Y ² and Z are the same.

As mentioned above, the compounds of the general formula (I) according to the invention are
The characteristics of the compound are X in each compound ¹, X²And X³Haso
Each independently, a hydrogen atom (H) or a deuterium atom (D)
And at least one of them is a deuterium atom.
(D). Therefore, R¹, Y¹, Y²And Z
Are the same, and X¹, X²And X³Only for different compounds
In the case where the compound of the general formula (I) includes stereoisomers,
There will be 10 compounds.

However, as will be described later, in the process of producing the compound of the general formula (I), it is safe to use some of these compounds in the form of a mixture. On the contrary, when used as a mixture, it is characterized in that it is less likely to cause crystal precipitation in a low temperature range and that the compatibility with other liquid crystal compounds is improved.

In the mixture of general formula (I) according to the invention:
In order to obtain the excellent effects as described above, the general formula (I)
The total number of deuterium atoms (D) in the two or more compounds represented by is 5 with respect to the total number of X ¹ , X ² and X ^3.
It is preferably 0% or more.

It is already known that a hydrogen atom is replaced with a deuterium atom (D) in a liquid crystal compound, and there are several reports as shown below. 1) H. Gasparoux et al., Ann.ReV.Phys.Chem., 27, 175 (1976) 2) GWGray et al., Mol.Cryst.Liq.Cryst., 41, 75 (1977) 3) AJ Leadbetter et al., J. Phys . [Paris] coll C3, 40,
125 (1979) 4) A. Kolbe et al., Z. Naturforsch., 23a, 1237 (1968) 5) JD Rowell et al., J. Chem. Phys., 43, 3442 (1965) 6) WD Philips et al., J. Chem. Phys ., 41, 2551 (1964) 7) AF Martins et al., Mol.Cryst.Liq.Cryst., 14, 75 (197
7) 8) ET Samulski et al., Phys. Rev. Lett., 29, 340 (1972).

In these reports, hydrogen atoms (H) in the carboxyl group of 4-alkoxybenzoic acid were all replaced by deuterium atoms (D) (Reference 1)), and all hydrogen atoms in the side chain ( H) is replaced with a deuterium atom (D), or the hydrogen atom (H) of the benzene ring is replaced with a deuterium atom (D).
It is only an example in which the hydrogen atom (H) of the cyclohexane ring was replaced by a deuterium atom (D) like the compound of the general formula (I) of the present invention was not known.

The mixture of the general formula (I) of the present invention can be produced, for example, as follows. That is, the general formula (III)

[0036]

[Chemical 7]

(In the formula, R ¹ has the same meaning as in formula (I)), instead of the 4-alkylcyclohexanone derivative represented by formula (II)

[0038]

[Chemical 8]

(In the formula, R¹Is an alkane having 1 to 12 carbon atoms
Represents a kill group, X¹, X², X³And X ^FourAre independent
Represents a hydrogen atom (H) or a deuterium atom (D)
But X¹~ X^FourAt least one of them represents a deuterium atom (D).
The cyclohexane ring is in the trans configuration. )
Deuterium-substituted 4-alkylcyclohexano
Two or more compounds selected from the group consisting of
(1) Number of deuterium atoms (D) and / or substitution positions of each other
Different, and (2) R¹Specially
From the compound represented by the general formula (II)
A mixture of two or more compounds selected from the group
By using it as an intermediate,
Same as for non-substituted phenylcyclohexane derivative
Can be manufactured.

More specifically, it can be obtained according to the following example.

[0041]

[Chemical 9]

A) In the general formula (I), Z = F, R
^2, -OR ^2, when the case of compounds that are -CF ₃ or -OCF ₃ Z is the above group, since it is inert to the Grignard reagent of general formula (IV) 4-bromo-body Directly react with magnesium as a Grignard reagent with a compound of the general formula (II), dehydrate the obtained cyclohexanol derivative to a cyclohexene derivative, and then hydrogenate it, and isomerize it to the trans form if necessary. Then, it can be obtained by separating and removing the cis form.

[0043]

[Chemical 10]

(B) In the general formula (I), Z = -OR
^In the case of the compound of ² or -OCH ₂ CF ₃ , the compound of Z = -OCH ₃ is used as the 4-bromo compound of the general formula (IV) in the above-mentioned a), and the same as in the above-mentioned a). it can be obtained Z = a -OCH ₃ compound in I). This is demethylated (trimethylsilyl iodide, boron tribromide, aluminum chloride, hydrobromic acid and the like can be used) to obtain the phenol derivative of the general formula (V). The compound of the general formula (V) was treated with R ² W or WCH ₂ CF in the presence of a base.
₃ (wherein, W is a bromine atom,. Representing a leaving group such as iodine or p- toluenesulfonyl group) by reaction with the general formula Z is -OR ² or -OCH ₂ CF ₃ (I ).

Alternatively, the phenol derivative of the general formula (V) can also be obtained by reacting the aniline derivative of the general formula (X) described below with sodium nitrite in an aqueous sulfuric acid solution to form a diazonium salt, and decomposing the salt. You can

[0046]

[Chemical 11]

C) In the general formula (I), Z = -OC
In the case of a compound which is F ₂ H, the compound of the general formula (V) obtained in the above (b) is used as a formic acid ester, which is used as dimethylaminosulfur trifluoride (D
It can be obtained by fluorinating by AST) or the like.

[0048]

[Chemical 12]

D) In the general formula (I), Z = -CN
In the case of the compound a) in the above a), instead of the compound of the general formula (IV),
By using the compound of general formula (VI), the compound of general formula (VII) in which Z = H in general formula (I) is obtained.

[0050]

[Chemical 13]

The compound of the general formula (VII) is reacted with oxalic acid chloride in the presence of a Lewis acid to give an acid chloride, and then reacted with ammonia to give the compound of the general formula (VIII).
Amide is obtained. By dehydrating this with thionyl chloride or the like, a compound having Z = -CN in the general formula (I) can be obtained.

[0052]

[Chemical 14]

Alternatively, this intermediate acid chloride is obtained by acetylating the compound of the general formula (VII) and then oxidizing it with bromine in an aqueous alkaline solution to give the carboxylic acid of the general formula (IX), and then thionyl chloride or the like. It can also be obtained by reacting with the chlorinating agent.

[0054]

[Chemical 15]

Alternatively, the compound of the general formula (VII) is directly iodinated with iodine / periodic acid, and then copper cyanide is used.
A compound with Z = -CN in the general formula (I) can also be obtained by reacting with (I).

[0056]

[Chemical 16]

(E) In the case of the compound of the general formula (I) in which Z = Cl, the amide of the general formula (VIII) can be reacted with bromine in an alkaline aqueous solution to obtain the aniline derivative of the general formula (X). By reacting this with sodium nitrite in the presence of hydrochloric acid to form a diazonium salt and decomposing it with copper (I) chloride, a compound in which Z = Cl in the general formula (I) can be obtained.

[0058]

[Chemical 17]

F) In the general formula (I), Z = -OC
In the case of the compound of N, it can be easily obtained by reacting the phenol derivative of the general formula (V) with cyanogen bromide in the presence of a base such as triethylamine.

[0060]

[Chemical 18]

In the above production process, when at least one of Y ¹ and Y ² in the general formula (I) is F, it is difficult to obtain the corresponding compound of the general formula (IV) in the above process a). In some cases. Alternatively, in the step (d), it may be difficult to selectively introduce the substituent Z at a desired position.

Therefore, in such a case, the intermediate compound of the general formula (VII) is lithiated with butyllithium or the like to give the phenyllithium derivative of the general formula (XI), which is directly alkylated ( In the general formula (I), Z =
R ² ) or carbon dioxide to obtain a carboxylic acid of the general formula (IX), which can be obtained by the above-mentioned method.

The general formula (II) used as an intermediate here
The deuterium-substituted 4-alkylcyclohexanone is also a novel compound, and the present invention also provides this compound.
The characteristic of the mixture of the general formula (II) is that X in each compound is
^1, X ^2, although X ³ and X ⁴ represent each independently a hydrogen atom (H) or a deuterium atom as described above (D), X ¹ ~
At least one of X ⁴ is at a point representing a deuterium atom (D).

By the way, the mixture of the above-mentioned general formula (I)
In the production method, X in the compound of general formula (II)
¹~ X^FourOne of the deuterium atoms (D) is represented by the general formula (I)
Lost by dehydration during the production of a mixture of
Subsequent hydrogenation results in replacement with hydrogen atoms (H)
It is clear that you will. At this time, X¹~ X^FourTo
There is no distinction between^FourDesorbs hydrogen
It is safe to assume that it will be replaced with a child (H).
Corresponding compounds of formula (I) of X ¹~ X³of
Showing only X^FourThe position corresponding to is placed on the hydrogen atom
It has a changed structure.

In order to obtain excellent properties of a mixture of two or more compounds selected from the group consisting of the compounds represented by the general formula (I) of the present invention, the deuterium atom (D) in the whole mixture must be The total number (hereinafter referred to as D conversion rate) is
It is preferably 50% or more with respect to the total number of X ¹ , X ² and X ³ .

Therefore, even in a mixture of two or more compounds selected from the group consisting of the corresponding compounds of the general formula (II), the total number of deuterium atoms (D) (D conversion rate) in the entire mixture is X. It is preferably 50% or more, and particularly preferably 70% or more with respect to the total number of ^{1 to} X ⁴ .

This compound of the general formula (II) is prepared by dissolving the corresponding 4-alkylcyclohexanone of the general formula (III) which is not substituted by deuterium in an aprotic solvent such as dichloromethane and reacting with a base such as an alkali metal alcoholate. Underneath, it can be obtained by reacting with heavy water (D ₂ O). The temperature of the reaction is preferably in the range of room temperature to the reflux temperature of the solvent, and in order to accelerate the reaction, it is also preferable to coexist with a quaternary ammonium salt such as tetrabutylammonium bromide.

Table 1 shows examples of the mixture of the compounds of the general formula (I) thus obtained and the phase transition temperatures thereof.

[0069]

[Table 1]

(In the table, Cr is a crystalline phase, N is a nematic phase, Sm is a smectic phase, and I is an isotropic liquid phase. In addition, () indicates a monotropic phase. The D conversion ratio is X ¹ in the mixture.
Shows the ratio of deuterium atoms (D) to the total number of to X ^3. )

The mixture of the general formula (I) can be used to solve the problem of crystal precipitation in the low temperature region of the liquid crystal composition. For example, (No. 1) to (N in Table 1)
o. Mixed liquid crystal (A) comprising the compound of 3)

[0072]

[Chemical 19]

(In the formula, "d _3- " is a mixture of compounds of the general formula (I) in which at least one of the substituents X ^{1 to} X ³ is a deuterium atom (D). Was prepared, and "%" represents "% by weight."), And showed a nematic phase at 50.0 ° C or lower. When this mixed liquid crystal (A) was stored at −20 ° C., no crystal precipitation could be observed even after 1 month.

On the other hand, (No. 1) to (No. 3)
Of the formulas (R-1) to (R-3), which have a similar structure to each of the compounds of formula (B), but are not substituted with deuterium.

[0075]

[Chemical 20]

(In the formula, "%" represents "% by weight".)
Was prepared, it exhibited a nematic phase at 50.5 ° C. or lower. When this mixed liquid crystal (B) was similarly stored at −20 ° C., crystal precipitation was observed after 7 days.

Therefore, the deuterium-substituted mixture of the general formula (I) according to the present invention is extremely useful for preparing a liquid crystal composition in which crystals do not precipitate for a long period of time in a low temperature region.

[0078]

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 a nuclear magnetic resonance spectrum ( NM
R), mass spectrum (MS), infrared absorption spectrum (IR), etc. The D conversion rate was measured by NMR, and the NMR used for the measurement was JNM-GSX400 (400 MHz ¹ H) manufactured by JEOL Ltd.

[0080] Incidentally, "d ₄ -" in formula (II), the substituents of X ¹ to X ^4, indicates that a mixture of at least one is made of compounds which are deuterium atoms (D) Similarly, “d ₃ −” represents X ¹ to
It represents a mixture of compounds in which at least one of the substituents of X ³ is a deuterium atom (D). Further, "%" in the composition represents "% by weight".

Example 1 Deuteration of 4-propylcyclohexanone

[0082]

[Chemical 21]

2.4 g of sodium methoxide was added to heavy water (D
The conversion rate: 99.8%) was dissolved in 20 ml. To this was added 18.5 g of 4-propylcyclohexanone dissolved in 20 ml of dichloromethane, and the mixture was heated and stirred at the reflux temperature of the solvent for 9 hours. After cooling, the organic layer was separated, and the aqueous layer was extracted with dichloromethane and then collected. Combine the organic layers, wash with water,
It was dehydrated and dried over anhydrous sodium sulfate.

The solvent was distilled off and deuterium-substituted d ₄ − was added.
17.6 g of 4-propylcyclohexanone was obtained. NM
When the D conversion rate was measured by R, it was about 91%.

[0085] In the same manner as Example 2 4-butyl-cyclohexanone deuterated Example 1 to obtain a d _4-4-butyl cyclohexanone is deuterated. When the D conversion rate was measured by NMR, it was about 89%.

[0086] In the same manner as Example 3 4-pentyl deuterated Example 1 of cyclohexanone to obtain a d _4-4-pentyl cyclohexanone is deuterated. When the D conversion rate was measured by NMR, it was about 87%.

[0087] In the same manner as Example 4 deuterated Example 1 4-heptyl cyclohexanone, to yield the d _4-4-heptyl cyclohexanone is deuterated. When the D conversion rate was measured by NMR, it was about 87%.

Example 5 d ₃ -1-cyano-4-
Synthesis of (trans-4-propylcyclohexyl) benzene

[0089]

[Chemical formula 22]

(5-a) d₃-1-phenyl-4-p
Synthesis of ropyr-1-cyclohexene Shaving in 5 ml of dry tetrahydrofuran (THF)
5.2 g of magnesium powder was added. Bromobenze
A solution of 28.0 g of THF in 120 ml of gentle reflux.
Was added dropwise at a sustained rate. Stir for another 30 minutes after dropping
I stirred. D obtained in Example 1 under ice cooling_Four-4-Prop
A solution of 16.6 g of rucyclohexanone in 50 ml of THF
For 40 minutes, taking care not to let the internal temperature exceed 40 ° C.
Defeated After stirring for another 30 minutes at room temperature,
Hydrochloric acid was added until the aqueous layer was slightly acidic. Vinegar the reaction product
It was extracted twice with 200 ml of ethyl acetate, and the organic layer was saturated brine.
It was washed with and dried over anhydrous sodium sulfate. Solvent
Evaporate under reduced pressure to give an oily d _Four-1-phenyl-4-p
A crude product of ropyr-1-cyclohexanol was obtained.

The total amount was dissolved in 100 ml of toluene,
1.0 g of potassium hydrogensulfate was added, and the mixture was heated under reflux for 1 hour while stirring to remove water that distilled out. After allowing to cool to room temperature, the reaction mixture was washed with water, saturated aqueous sodium hydrogen carbonate solution, water and saturated brine, and dehydrated and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to obtain a d _{3-1-phenyl-4-propyl-1-cyclohexene} 23.5 g.

(5-b) Synthesis of d _3- (trans-4-propylcyclohexyl) benzene d ₃ -1 obtained in (5-a) above in an autoclave
-Phenyl-4-propyl-1-cyclohexene 23.
5 g was added and dissolved in 200 ml of ethyl acetate. 2.5g of palladium carbon was added to this, and the hydrogen pressure was 4Kg / cm.
Stir at ² for 3 hours at room temperature. The catalyst was removed by filtration through Celite, and the solvent was distilled off under reduced pressure to obtain d _3- (4-propylcyclohexyl) benzene (cis / trans mixture). N, N-dimethylformamide (D
MF) dissolved in 115 ml, potassium t-butoxide 1
0.0g was added and it stirred at 110 degreeC for 3 hours. Water 100
ml was added, neutralized with dilute hydrochloric acid, and the reaction product was extracted twice with hexane. The hexane layer was washed with water, dehydrated and dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product, which was purified by silica gel column chromatography (hexane) to give d ₃ -(Trance-4
-Propylcyclohexyl) benzene and d _3- (cis-
20.2 g of a 86/14 mixture of 4-propylcyclohexyl) benzene was obtained.

[0093] _{(5-c) d 3 -} ( trans-4-propyl-cyclohexyl) benzamide above (5-b) obtained in d ₃ - (trans-4-propyl-cyclohexyl) benzene and d ₃ - (cis 86/14 mixture of -4-propylcyclohexyl) benzene 1
0.0 g was dissolved in 50 ml of dichloromethane, 8.6 g of anhydrous aluminum chloride was added, and the mixture was ice-cooled. 6.9 g of oxalic acid dichloride dissolved in 30 ml of dichloromethane was added dropwise with care so that the internal temperature did not exceed 10 ° C. After stirring for 1 hour under ice cooling, the reaction solution was poured into diluted hydrochloric acid and ice, and the reaction product was extracted with dichloromethane. 10 ml of this dichloromethane solution was added to 150 ml of 29% aqueous ammonia under ice cooling.
It was added dropwise at a temperature of not higher than 0 ° C. After stirring for 1 hour at 5 to 10 ° C., the precipitated crystals were collected by filtration, dried under reduced pressure, and d ₃ −
12 g of crude crystals of (trans-4-propylcyclohexyl) benzamide (containing a small amount of cis isomer) were obtained.

[0094] (5-d) d ₃ -1- cyano-4- (trans-4-propyl-cyclohexyl) benzene Synthesis of (5-c) obtained in d ₃ - (trans-4-propyl-cyclohexyl) benzamide Toluene 5
The suspension was suspended in 0 ml, thionyl chloride (20 ml) was added, and the mixture was heated with stirring under reflux for 1 hour. After allowing to cool, add water and stir,
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 solvent was distilled off, and the obtained crude product was purified by silica gel column chromatography (toluene) and further recrystallized from methanol to give d ₃ -1-cyano-4- (trans-4-propylcyclohexyl). ) Benzene 5.4
g was obtained. When the D conversion rate was measured by NMR, it was about 85%. The phase transition temperature was as follows.

Phase transition temperature (° C.): melting point 40 ° C. (Cr →
I), 46 ° C (N-I) The phase transition temperature of 1-cyano-4- (trans-4-propylcyclohexyl) benzene which is not deuterated has a melting point of 42 ° C (N-I). ) Point is 45 ° C.

Example 6 d ₃ -1-cyano-4-
Synthesis Example 5 (trans-4-pentylcyclohexyl) benzene in place of the d ₄ 4-propyl cyclohexanone, except for using the d ₄ 4 pentylcyclohexanone obtained in Example 3 and Example 5 Similarly,
d ₃ -1-Cyano-4- (trans-4-pentylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 7 d ₃ -1-cyano-4-
Synthesis Example 5 (trans-4-heptylcyclohexyl) benzene in place of the d ₄ 4-propyl cyclohexanone, except for using the d ₄ 4-heptyl cyclohexanone obtained in Examples 4 and 5 Similarly,
d ₃ -1-Cyano-4- (trans-4-heptylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 8 Synthesis of d ₃ -1-cyano-2-fluoro-4- (trans-4-propylcyclohexyl) benzene In Example 5, instead of bromobenzene, 3-fluoro-1-bromo was used. except that benzene was used in the same manner as in example 5 to give the d _3-1-cyano-4- (trans-4-propyl-cyclohexyl) -2-fluorobenzene. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 9 d ₃ -4-ethoxy-1-
Synthesis of (trans-4-propylcyclohexyl) benzene

[0100]

[Chemical formula 23]

4-bromo-1-ethoxybenzene 20.
A Grignard reactant was prepared in the same manner as in Example (5-a) from 0 g, 2.6 g of magnesium, and 100 ml of THF. To this was reacted analogously to d ₄ 4-propyl cyclohexanone 16.7g in 40 ml of THF, to give the d _4-1- (4-ethoxyphenyl) -4-propyl-1 crude cyclohexanol oil It was The total amount in the same manner by reacting with potassium hydrogen sulphate in toluene, d _3-1- (4-propyl-1-cyclohexene -
25.5 g of 1-yl) -4-ethoxybenzene was obtained.
This was hydrogenated in the same manner as in Example (5-b), the obtained crude product was purified by silica gel column chromatography (toluene / hexane), and recrystallized from methanol to give d ₃ -4-ethoxy-1- (trans-4-propylcyclohexyl) benzene 12.0 g
Got The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 10 d ₃ -4-methoxy-1
Synthesis of-(trans-4-pentylcyclohexyl) benzene In Example 9, 4-bromo-1-methoxybenzene was used instead of 4-bromo-1-ethoxybenzene,
Instead of d _4-4-propyl cyclohexanone, d ₄ -4
- except using pentylcyclohexanone in the same manner as in Example 9, d ₃ -4- methoxy-1- (trans-4
-Pentylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 11 d ₃ -4-pentyl-1
Synthesis of-(trans-4-propylcyclohexyl) benzene In the same manner as in Example 9 except that 4-bromo-1-pentylbenzene was used instead of 4-bromo-1-ethoxybenzene in Example 9, d ₃ -4- pentyl -1
-(Trans-4-propylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 12 d ₃ -4-fluoro-1
Synthesis of-(trans-4-pentylcyclohexyl) benzene In Example 9, 1-bromo-4-fluorobenzene was used instead of 4-bromo-1-ethoxybenzene,
d ₄ - instead of trans-4-propyl cyclohexanone, obtained in Example 3 d ₄ - except for using trans-4-pentylcyclohexanone in the same manner as in Example 9, d ₃ -4- fluoro -1 -(Trans-4-pentylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

[0105] (Example 13) d _{3-3,4-difluoro-1} Synthesis Example 9 (trans-4-pentylcyclohexyl) benzene in place of the 4-bromo-1-ethoxy benzene, 1-bromo using 3,4-difluorobenzene, d ₄ - instead of trans-4-propyl cyclohexanone, d ₄ obtained in example 3 - except that a trans-4-pentylcyclohexanone in the same manner as in example 9 Te, d _{3-3,4-difluoro-1-} (trans -
4-pentylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Embodiment 14) d₃-4-trifluoro
Methoxy-1- (trans-4-propylcyclohexyl
B) Synthesis of benzene In Example 9, 4-bromo-1-ethoxybenzene
In place of 4-bromo-1-trifluoromethoxyben
D was the same as in Example 9 except that Zen was used. ₃-4-
Trifluoromethoxy-1- (trans-4-propyl
Cyclohexyl) benzene was obtained. D conversion rate and phase transition temperature
The degrees are summarized in Table 1.

Example 15 d ₃ -4- (trans-
Synthesis of 2-butenyloxy) -1- (trans-4-pentylcyclohexyl) benzene

[0108]

[Chemical formula 24]

[0109] _{(15-a) d 3 -4-} ( trans-4
- pentylcyclohexyl) d ₃ -4- methoxy obtained in Synthesis Example 10 of phenol-1- (trans-4-pentylcyclohexyl) benzene 4.0g
Was heated and stirred in 50 ml of acetic acid and 50 ml of 50% hydrobromic acid under reflux for 20 hours. After allowing to cool, the reaction solution was poured into water, and the reaction product was extracted with toluene. After washing with water, and the solvent was distilled off under reduced pressure, and the obtained crude product was recrystallized from hexane to give d ₃ -4- (trans-4-pentylcyclohexyl) phenol 3.0g .

[0110] _{(15-b) d 3 -4-} ( trans-2
- butenyloxy)-1-(d ₃ -4- obtained trans-4-pentylcyclohexyl) benzene Synthesis of (15-a) (trans-4
-Pentylcyclohexyl) phenol 1.5 g TH
It was dissolved in F5 ml. This was added dropwise to 150 mg of sodium hydride suspended in 15 ml of THF, and the mixture was stirred for 3 hours. 1.0 g of trans-1-bromo-2-butene
5 ml of THF solution was added dropwise, and the mixture was further heated and stirred under reflux for 6 hours. After allowing to cool, water was added and dilute hydrochloric acid was added to weakly acidify the reaction product, and the reaction product was extracted with toluene. After washing with water,
The oily crude product obtained by distilling off the solvent under reduced pressure was purified by silica gel column chromatography (toluene / hexane) and recrystallized from methanol.
d _{3-4-(trans-2-butenyloxy)} -1-
1.1 g of (trans-4-pentylcyclohexyl) benzene was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

(Example 16) d ₃ -1-Cyanato-4
Synthesis of-(trans-4-pentylcyclohexyl) benzene

[0112]

[Chemical 25]

D ₃ -4-obtained in the above (15-a)
1.5 g of (trans-4-pentylcyclohexyl) phenol was dissolved in 50 ml of 2-butanone, 2 ml of triethylamine was added, and the mixture was ice-cooled to 5 ° C. To this, a solution of 1.0 g of cyanogen bromide in 5 ml of acetone was added dropwise over 30 minutes,
Further, the mixture was stirred at the same temperature for 4 hours. The reaction solution was poured into water, the reaction product was extracted with toluene, washed with water, and the solvent was distilled off. The obtained crude product was purified by silica gel column chromatography (toluene / hexane), and recrystallized from ethanol to give d ₃ -1-cyanato-4- (trans-4-pentylcyclohexyl) benzene crystal 0.8.
g was obtained. The D conversion rate and the phase transition temperature are summarized in Table 1.

Example 17 Preparation of Liquid Crystal Composition (No. 1) and (No. 1) obtained in Examples 5, 6 and 7.
2), a mixed liquid crystal (A) composed of each mixture of (No. 3)

[0115]

[Chemical formula 26]

When prepared, a nematic phase was exhibited at 50 ° C. or lower. When this mixed liquid crystal (A) was stored at −20 ° C., no crystal precipitation was observed even after 1 month.

(Comparative Example) Formulas (R-1), (R-2) and (R-3) having similar structures to the mixtures obtained in Examples 5, 6 and 7 but not having deuterium substitution. ) Mixed liquid crystal (B) comprising each compound

[0118]

[Chemical 27]

As a result, a nematic phase was exhibited at 50.5 ° C. or lower. Similarly, when it was stored at -20 ° C, precipitation of crystals was observed after 7 days. Therefore, the deuterium-substituted mixture of the general formula (I) of the present invention has an excellent compatibility with other liquid crystal compounds as compared with a compound having a similar structure, and further has an effect of making it difficult to precipitate crystals in a low temperature region. It is apparent that the temperature range that can be driven is substantially expanded.

[0120]

INDUSTRIAL APPLICABILITY The mixture of the deuterium-substituted phenylcyclohexane derivatives represented by the general formula (I) of the present invention can be easily produced industrially from commercially available compounds as shown in Examples. can do.

Further, the mixture of the compounds represented by the general formula (I) is excellent in compatibility with other liquid crystal compounds, and in the low temperature range, which is a problem of liquid crystal materials which are currently widely used. It is possible to prepare a liquid crystal composition in which crystals are prevented from precipitating and crystals do not precipitate even at −20 ° C. for a long time. Moreover, the electro-optical characteristics are not significantly reduced.

Therefore, it is extremely useful as a constituent material of a liquid crystal display device used in a low temperature region.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C07C 261/02 7188-4H C09K 19/30 9279-4H G02F 1/13 500 // C07B 59/00 7419-4H

Claims (10)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, X ¹ , X ² and X ³ each independently represent a hydrogen atom (H) or a deuterium atom (D), 1
Represents a deuterium atom (D), Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom, and Z represents a fluorine atom, a chlorine atom, a cyano group, —R ² , —OR ² , or —. CF
_{3, -OCF 3, -OCF 2 H} , -OCN or -OCH ₂ C
F ₃ represents R ₃ , R ² represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms, and the cyclohexane ring has a trans configuration. ) At least two compounds selected from the group consisting of compounds represented by
(1) The number of deuterium atoms and / or the substitution position are different from each other, and (2) R ¹ , Y ¹ , Y ² and Z are the same as each other, represented by the general formula (I). A mixture consisting of two or more compounds selected from the group consisting of: 2. R ¹ represents a linear alkyl group having 1 to 7 carbon atoms, Z represents a fluorine atom, a cyano group, a linear alkyl group or alkoxyl group having 1 to 7 carbon atoms, or the number of carbon atoms. 2-7 linear alkenyloxy group, a mixture of claim 1, wherein a representative of the -OCF ₃ or -OCN. 3. The mixture according to claim ^2, wherein the proportion of deuterium atoms (D) is 50% or more based on the total number of X ¹ , X ² and X ³ . 4. The mixture according to claim 3, wherein Z is a cyano group, and Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom, at least one of which is a hydrogen atom. . 5. Z is a fluorine atom, and Y ¹ and Y ² each independently represent a hydrogen atom or a fluorine atom,
A mixture according to claim 3, characterized in that at least one represents a hydrogen atom. 6. Z represents a straight-chain alkyl group having 1 to 5 carbon atoms, an alkoxyl group or a straight-chain alkenyloxy group having 2 to 7 carbon atoms, and Y ¹ and Y ² are both a hydrogen atom or fluorine. 4. The mixture according to claim 3, characterized in that it represents an atom. 7. In the general formula (I), Z is —OCF ₃
Or represents -OCN, mixture of claim 3, wherein Y ¹ and Y ^2, characterized in that the both represent a hydrogen atom. 8. A compound represented by the general formula (II):(In the formula, R¹Represents an alkyl group having 1 to 12 carbon atoms
Then X¹, X², X³And X ^FourAre each independently a hydrogen atom
(H) or a deuterium atom (D), but X¹~ X ^FourNou
At least one of them represents a deuterium atom (D). )
Compounds passed down. 9. A compound represented by the general formula (II):(In the formula, R¹Represents an alkyl group having 1 to 12 carbon atoms
Then X¹, X², X³And X ^FourAre each independently a hydrogen atom
(H) or a deuterium atom (D), but X¹~ X ^FourNou
At least one of them represents a deuterium atom (D). )
Two or more compounds selected from the group consisting of compounds
Are (1) the number and / or the number of deuterium atoms (D) of each other.
Different replacement positions, and (2) R¹Are the same
A compound represented by the general formula (II), characterized by
A mixture consisting of two or more compounds selected from the group consisting of
Stuff. 10. The mixture according to claim 9, wherein the ratio of deuterium atoms (D) is 50% or more based on the total number of X ^{1 to} X ⁴ .