JPS59110651A - Novel nematic liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:A compound of formula I (R1, R2 are 1-7C straight-chain alkyl). USE:Electro-optic display material: it is used in dynamic scattering mode display cells, field effect mode display cells or the like. The mixture thereof with one or more other nematic liquid crystal compounds shows a raised nematic-isotropic phase transition point above 65 deg.C, but scarcely raises the viscosity of the mixture. PREPARATION:After acetylation of a compound of formula II to a compound of formula III, oxidation is carried out to give a compound of formula IV, which is ?catalytically hydrogenated in the presence of a catalyst such as Ru-C, followed by thermal rearrangement to a compound of formula V. The product is made to react with a halogenating agent into a compound of formula VI (X is halogen), then p-alkylphenol is made to react therewith to a give the compound of formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of cyclohexane derivatives useful as electro-optic display materials. The novel nematic liquid crystal compound provided by the present invention is a compound represented by the general formula.

M-Shut (M-8) is a typical liquid crystal display cell.
chadt ) etc. (APPLIED P) ffsIcs
LETTER3±Higashi 127-128 (1971)] or CpRocgE such as G-1ichi + Beilmeier
DxNG OF THE I, E, E, E, 1
1162 to 1171 (1968)] or the dynamic scattering mode cell proposed by G.H.
Heilmeier) etc. CAPPLIED PHYS
IC8LETTER813, 91 (1968)) or D L White etc. [JOURNAL OF APPLIED Pi (YS
There is a guest-host type cell proposed by IC845, 4718 (1974).

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

A large number of practically available materials with such properties (usually consists of a mixture of several or more components consisting of a compound that has a nematic phase near room temperature and a compound that has a nematic phase at a temperature higher than room temperature) It is prepared by combining many of the above-mentioned mixed liquid crystals currently in practical use.
is required to have a nematic phase over the entire temperature range from -60°C to ±65°C. , 4,4'-substituted terphenyl, 4,4'-substituted biphenylcyclohexane, 4,
4'-substituted benzoyloxybenzoic acid phenyl esters, which have a crystal phase-nematic phase transition temperature of about 100°C
C-N point) and a nematic phase at about 200°C.
Compounds with an isotropic liquid phase transition temperature (N-I point) are often used. However, these compounds have the unfavorable property of increasing the viscosity of the resulting mixed liquid crystal, thereby decreasing the response speed.

The compound of formula (I) according to the present invention is a novel compound with improved properties. That is, by mixing with one or more other nematic liquid crystal compounds, a practically usable mixed liquid crystal having an N-I point of 65° C. or higher is prepared.
Compared to the above-mentioned known liquid crystal compounds, the increase in viscosity of the mixed liquid crystal can be suppressed to a much smaller extent.

The compound of formula (I) according to the present invention can be produced, for example, according to the following production method.

First step: A compound of formula (■) is prepared by reacting the compound of formula (n)s with acetyl chloride and anhydrous aluminum chloride in carbon disulfide or nitrobenzene.

In the second step, the compound of formula (III) is reacted with a sodium hydroxide solution of sodium hypochlorite or sodium hypobromite in dioxane to produce a compound of formula (IV).

Sixth step: After hydrogen reduction of the compound of formula (IV) in a sodium hydroxide solution using a reduction catalyst such as R11-C, acidification is performed to take out the liberated carboxylic acid, which is thermally transferred to form the formula (
Produce the compound V).

Fourth step: A compound of formula (V) is reacted with a halogenating agent to produce a compound of formula (Vl) (in formula 3, X is a halogen atom). In the compound of formula (Vl), X is preferably a chlorine atom, and thionyl chloride may be used as the halogenating agent.

Fifth step - The present invention involves reacting the compound of formula (VI) produced in the fourth step with p-alkylphenol in an inert organic solvent such as ether, benzene, or toluene using a basic compound such as pyridine as a catalyst. A compound of formula (I) according to is prepared.

The transition temperatures of representative compounds of formula (I) thus produced are shown in Table 1.

The compound of formula (I) according to the present invention is a nematic liquid crystal compound with weak negative dielectric constant anisotropy, and therefore, for example,
It can be used as a material for dynamic light scattering display cells in a mixture with other nematic liquid crystal compounds that have negative or weak positive dielectric anisotropy, and also has strong positive dielectric anisotropy. It can be used as a material for field effect display cells in the form of a mixture with other nematic liquid crystal compounds.

Thus, preferred representative examples which can be used in admixture with the compound of formula (I) include, for example, 4,4'-substituted benzoic acid phenyl ester, 4,4'-[substituted cyclohexanecarboxylic acid phenyl ester] , 4,4'-substituted cyclohexanecarboxylic acid piphenyl ester, 4(
4-ft-substituted fucyclohexanecarbonyloxybenzoic acid 4'-substituted phenyl ester 4(4-9-substituted cyclohexyl)benzoic acid 4'-substituted phenyl ester, 4(4-substituted cyclohexyl)benzoic acid 4'-substituted cyclohexyl ester, 4 r 4' e phenyl, 4, 4'
-phenylcyclohexane, 4,4'-terphenyl, 4,4'-biphenylcyclohexane, 2(4'
-fil substituted phenyl) 5-substituted pyrimidine, and the like.

Table 2 shows the 80% by weight and the 1st
Compounds of formula (I) shown in the table /I61, /162, /1
The N-I point and viscosity measured for each mixed liquid crystal consisting of 20% by weight of each of Condition 4, Washing 5, and A6 are posted, and for comparison, the N-I point and viscosity measured for the base liquid crystal (A) itself are shown. -I point and viscosity are displayed. The parent liquid crystal is as follows: and Table 2 N-1 point Viscosity ('C) (c, p, /20°C) (~ 54.0 21.0 (A) + (/161) 7, 6 23. 0(
A) + (42) 72.9 2s,.

(A)+ <y18> 76.0 23.1
Prisoner + (A4) 76.3
2 6.6(Al+ (A
5) 76.3 23.3 prisoners + (/166)
75.1 23.6 From the data posted in Table 2, it can be seen that the compound of formula (I) increases the N-1 point of the mixed liquid crystal without substantially increasing the viscosity of the mixed liquid crystal. Approximately 26cm boise/20 in Table 2
The viscosity value at 70°C is at the current average practical level.
This value is considerably lower than the viscosity values of various mixed liquid crystals having the above N-1 point. The practical high value of the compound of formula (I) 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. The chemical structure is similar to the compound of formula (I) according to the present invention, and a wide range of (
The known compounds of the formula (used) were mixed in various proportions with the above-mentioned base liquid crystal (B).

Similarly, one of the compounds according to the present invention, ie, the compound of formula (3), was mixed with the parent liquid crystal (A) in various proportions. Regarding the two types of mixed liquid crystals obtained in this way, each N-
One point and viscosity were measured. Based on these measurement results, the relationship between viscosity and NI point is shown in FIG. 1 of the attached drawings. As a result, when a typical known similar compound is gradually added, the viscosity of the resulting mixed liquid crystal increases significantly as the N-1 point increases, whereas ), it will be understood that the increase in viscosity accompanying the increase in the N-1 point of the resulting mixed liquid crystal is much smaller.

Example: Anhydrous aluminum chloride 16.0 in 100ml carbon sulfide
．． 9 (0,120 mol) and acetyl chloride Z8FJ' (0,100 mol) was added thereto while stirring at room temperature.

This was cooled to 10°C, and while stirring, a liquid solution prepared by dissolving formula % in carbon disulfide 5ON was added dropwise, and the mixture was heated to 10°C.
After reacting for 5 hours, the mixture was returned to room temperature and reacted for 2 hours.

After the reaction, carbon disulfide was distilled off and then added to ice water.
Stirred at 0'C for 1 hour. After cooling, extract with toluene, wash with water, dry, distill off the toluene, recrystallize with ethanol,
22.9 g (0,0842 mol) of the following compound was obtained.

This compound was dissolved in dioxane 230% and 30 to 65%
Keep at ℃. While stirring, add 150 g of 12% sodium hypochlorite, 13.4 g of sodium hydroxide, and 13.0 g of water.
7 cc of bath liquid was quickly added dropwise. 40-50℃ after dropping
After reaction for 2 hours, the mixture was further heated to 80°C. After the reaction was completed, it was cooled and acidified with hydrochloric acid, and the precipitated crystals were filtered, washed with water, and dried to obtain 18.7 g (0,0682 mol) of the following compound.
I got it.

This compound was mixed with 85% sodium hydroxide 3.51 (0,0
750 mol) was dissolved in 300 W of water, and this (5% Ru-
C, add 15 g of catalyst containing 70% water and make 80" C1 hydrogen 3 a
It was reduced with tm. After completion of the reduction, the reaction product was filtered to remove the catalyst, the filtrate was made acidic with dilute hydrochloric acid, the precipitate was extracted with ether, washed with water, dried, and the ether was distilled off. This was heated at 200° C. for 24 hours in a nitrogen stream. After thermal transition, this was recrystallized from ethanol to obtain the following compound 16.55 (
0.0, [14B2 mol) was obtained.

100 g of thionyl chloride was added to this compound and the mixture was refluxed for 3 hours. After the reaction, thionyl chloride was distilled off, and toluene 60α
dissolved in.

Add this solution to 50cc toluene at 6.56.9 (0.04
The solution was added dropwise to a bath liquid in which 82 mol) of p-propylphenol and 7.69 mol of pyridine were dissolved while stirring at 10°C. After the completion of the dropwise addition, the reaction was carried out at reflux temperature for 2 hours, and after the completion of the reaction,
The reaction product was extracted with toluene. After washing the extract with water and drying, toluene was distilled off from this liquid, and the obtained reaction product was recrystallized from ethanol to obtain 14.6 g of the following compound (
0,0367 mol) was obtained.

Yield 367% Transition temperature 128℃ (('-+5
) 131°C (sgN) 165°C (N-I) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield 34.9% Transition temperature 115°C (C→N
) 152°C (NdI) Example 6 The following compound was obtained in the same manner as in Example 1.

Yield: 351% Transition temperature: 112°C (C-+N
) 149°C (N; 1=2I) Example 4 The following compound was obtained in the same manner as in Example 1.

Yield 37.1% Transition temperature 129°C (C-+3
) 1356C (S#N) 167°C (NdI) Example 5 The following compound was obtained in the same manner as in Example 1.

Yield 36.2% Transition temperature 127°C (C-+S
) 134°C (SdN) 166°C (N≧I) Example 6 The following compound was obtained in the same manner as in Example 1.

Yield 37.4% Transition temperature 124°C (C-+5
) 147°C (SμN) 166°C (N!I)

[Brief explanation of drawings]

Figure 1 shows the crystals of a mixed liquid crystal obtained by adding the compound of condition 6, which is one of the compounds according to the present invention, and the known compound 7, which has a similar structure to this, to a mother liquid crystal that is currently widely used. It is a chart showing the relationship between anti and N'-I points.

Claims (1)

[Claims] A compound represented by