JPS5933565B2 - 1-Cyclohexyl-2-cyclohexylbiphenylethane derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides etanne R□ useful as an electro-optical display material.
CH2CH2 ([wherein, R4 and R2 each have 1 to 1 carbon atoms]
7 represents a straight-chain alkyl group.

] 1-(trans(equatorial-equatorial)-4'-n-alkylcyclohexyl)-2-
4″1 (Trans (Ekatoria-Ekatorial)-4
″'-n-alkylcyclohexylbiphenyl)ethane.

A typical liquid crystal display cell is M-S
ehadt) etc. [APPL1EDPHY51C5LET
TER518127-128 (1971)] or the field effect mode cell proposed by G.H.
H Heilmeier) etc. [PROCEEDINGOF
THEI, E, E, E.

This invention relates to novel nematic liquid crystal compounds of derivatives. The novel nematic liquid crystal provided by the present invention has the general formula 5611
62-1171 (1968)].
Cell) or G-H Heilmeyer (G-HHe
ilmeier) etc. [APPLIEDPHYSICSL
ETTERS 13, 91 (1968)] or DL White etc. [JOURN
ALOFAPPLIEDPHYSICS mouth, 4718 (
For example, there is a guest-host type cell proposed by [1974].

The liquid crystal materials used in these liquid crystal display cells are required to have various properties, but having a nematic phase in a wide temperature range including room temperature is an important property that is commonly required for all types of display cells. .

Many of the materials that can be used for practical purposes with such properties are usually obtained by mixing several or more components, which consist of a compound that has a nematic phase near room temperature and a compound that has a nematic phase above room temperature. It is then prepared.
Most of the above-mentioned mixed liquid crystals currently in practical use are
It is required to have a nematic phase over the entire temperature range of at least -30°C to +65°C. In order to meet such requirements, 4,4' monosubstituted terphenyl, 4
・47 Monosubstituted biphenylcyclohexane, 4.4/monosubstituted benzoyloxybenzoic acid phenyl ester, etc.
Crystal phase-nematic phase transition temperature (C-N
Compounds having a nematic phase monoisotropic liquid phase transition temperature (N-1 point) of about 200 DEG C. are often used. However, these compounds have the undesirable property of increasing the viscosity of the resulting mixed liquid crystal, thereby decreasing the response speed. The compound of formula (1) according to the present invention is a novel compound with improved properties.

That is, when preparing a practically usable mixed liquid crystal having an N-1 point of 65°C or higher by mixing it with one or more other nematic liquid crystal compounds, the mixing ratio is lower than that of the above-mentioned known liquid crystal compounds. It is possible to suppress the increase in viscosity of liquid crystal to a much smaller extent. The compound of formula (1) according to the present invention can be produced, for example, according to the following production method.

In the first step, a compound of formula () is reacted with anhydrous aluminum chloride in carbon disulfide or nitrobenzene to produce a compound of formula ().

Second Step - The compound of formula () produced in the first step is reacted with hydrazine and potassium hydroxide in diethylene glycol or triethylene glycol to produce a compound of formula (I).

The transition temperature of the compound of formula (I) thus produced is
Listed in the table. The compound of formula (1) according to the present invention is a nematic liquid crystal compound having a weak negative dielectric anisotropy, and therefore can be used, for example, with other nematic liquid crystal compounds having a negative or weak positive dielectric anisotropy. It can be used as a material for dynamic light scattering display cells in a mixture state, and as a material for field effect display cells in a mixture state with other nematic liquid crystal compounds with strong positive dielectric constant anisotropy. can be used.

As described above, preferred representative examples that can be used in combination with the compound of formula (1) include 4,4' monosubstituted benzoic acid phenyl ester, 4,4' monosubstituted cyclohexanecarboxylic acid phenyl ester, etc. , 4,41 monosubstituted cyclohexanecarboxylic acid biphenyl ester, 4(4-monosubstituted cyclohexanecarbonyloxy)benzoic acid 4'-monosubstituted phenyl ester 4(4-monosubstituted cyclohexyl)benzoic acid 4/i★monosubstituted phenyl ester, 4(4-monosubstituted cyclohexyl)benzoic acid 4'-monosubstituted cyclohexyl ester5l, 4,4'-biphenyl, 4,4/-phenylcyclohexane, 4,4'-monosubstituted terphenyl, 4,4
Examples include 1-biphenylcyclohexane, 2(41-substituted phenyl)5-substituted pyrimidine, and the like.

Table 2 shows 90% by weight of the base liquid crystal (A), which is currently widely used as a nematic liquid crystal material with excellent time division 1 drive characteristics, and compounds of formula (1) shown in Table 1. 3
, black 4, black 5, black 6, black 7, black. 10% by weight of each of 8
The N-1 point and viscosity measured for each mixed liquid crystal consisting of are shown, and for comparison, the NI point and viscosity measured for the base liquid crystal (A) itself are shown.

In addition, the parent liquid crystal is and It consists of

From the data posted in Table 2, it can be seen that the compound of formula (1) can be applied to N-1 of the mixed liquid crystal without increasing the viscosity of the mixed liquid crystal.
You can understand that it increases the score.

The viscosity value of about 22 centipoise/20 DEG C. in Table 2 is considerably lower than the viscosity values of various mixed liquid crystals having an N-1 point of 65 DEG C. or higher, which is at the current average practical level. The practical value of the compound of formula (1) lies in the fact that mixed liquid crystals with such low viscosity can be obtained. The effects of the present invention are also clarified by the following comparative experiments.

A known compound of the formula whose chemical structure is similar to the compound of the formula () according to the present invention and which is widely used for the purpose of increasing the N-1 point of the mixed liquid crystal is added to the base liquid crystal (A) in various ways. mixed in proportion.

Similarly, one of the compounds according to the invention, ie a compound of the formula, was mixed into the parent liquid crystal (A) in various proportions.

Regarding the two types of mixed liquid crystals obtained in this way, each N
-1 point and viscosity were measured. Based on these measurement results,
FIG. 1 of the attached drawings shows the relationship between the N-1 point and the amount added, FIG. 2 shows the relationship between the viscosity and the amount added, and FIG. 3 shows the relationship between the viscosity and the N-1 point. These results, especially the results shown in Figure 3, show that when typical known similar compounds are added, the viscosity of the resulting mixed liquid crystal increases significantly as the N-1 point increases; It will be understood that when the compound of formula (1) according to the present invention is added, the increase in viscosity associated with the increase in the N-I point of the resulting mixed liquid crystal is much smaller.
Next, the present invention will be specifically explained using examples.

Anhydrous aluminum chloride 16 in 100ml carbon disulfide
．． 07 (0.120 m01) was added thereto, and 20.37 (0.100 m01) of trans-4-n-propylcyclohexyl acetic acid chloride was added dropwise while stirring at room temperature.

This was cooled to 0°C and trans-4-n-
Pentyl-1-biphenylcyclohexane 30.67 (
A solution prepared by dissolving 0.100 m01) in 50 m1 of carbon disulfide was added dropwise, and the mixture was reacted at 0°C for 5 hours, then returned to room temperature and reacted for 2 hours. After the reaction, carbon disulfide was distilled off, and the mixture was added to ice water and stirred at 60°C for 1 hour. After cooling, extract with ether, wash with water, dry, and after distilling off the ether, n-
After recrystallization and purification with hexane-ethanol, the following compound 37 was obtained.
．． 37 (0.0791 m01) was obtained. To this compound were added 100 ml of triethylene glycol, 6.337 (0.126 m01) of hydrazine hydride, and 13.1 f7 (0.234 m01) of potassium hydroxide, and the temperature was gradually raised while stirring, and the mixture was reacted at 180° C. for 3 hours. After cooling, 200 ml of water was added and extracted with n-hexane. After washing with water and drying over anhydrous sodium sulfate, n-hexane was distilled off and recrystallization was carried out with n-hexane-ethanol to obtain the following compound 26.4y (0.0576m01). Yield 57.6% Transition temperature 163°C (C-+S) 209
°C (S=N) 246 °C (N=I) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield 52.4% Transition temperature 133°C (C-+S) 196°C
(S=N) 228°C (N:I) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield 55.7% Transition temperature 172°C (C→S) 201°C (
Example 4 The following compound was obtained in the same manner as in Example 1.

Yield 51.9% Transition temperature 137°C (C→S) 198°C (
S=N)23'C(N=I) Example 5 The following compound was obtained in the same manner as in Example 1.

Yield 54.0% Transition temperature 125°C (C→S) 192°C (
S=N) 237°C (N=I) Example 6 The following compound was obtained in the same manner as in Example 1.

Yield 53.6% Transition temperature 145°C (C→S) 199°C (
S=N) 249°C (N=I) Example 7 The following compound was obtained in the same manner as in Example 1.

Yield 57.2% Transition temperature 17'C (C->S) 212°C
(S+: 2N) 261°C (N#I) Example 8 The following compound was obtained in the same manner as in Example 1.

Yield 56.6% Transition temperature 127°C (C-+S)2
15℃ (S=N) 262℃ (N=I)

[Brief explanation of drawings]

The drawings show compound No. 5, which is one of the compounds according to the present invention, and compound No. 9, which is a known compound having a similar chemical structure, added to a currently widely used base liquid crystal (A) in various proportions. Figure 1 shows the relationship between the N point and the amount added, Figure 2 shows the relationship between the viscosity and the amount added, and Figure 3 shows the relationship between the viscosity and the N-1 point. ing.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_1 and R_2 each represent a linear alkyl group having 1 to 7 carbon atoms. ] A compound represented by