JPS63250332A - Fluorotrane based nematic compound - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I (R and R' are 1-9C straight-chain alkyl; cyclohexane ring has trans configuration). USE:A liquid crystal compound having high N-I transition temperature and large DELTAn. PREPARATION:A magnesium bromide obtained by reacting a compound expressed by formula II with Mg powder is reacted with 4-n-alkylcyclohexanone to afford a compound expressed by formula III, which is then dehydrated, catalytically reduced by a hydrogenation catalyst and reacted with periodic acid.2 hydrates in a mixed solvent consisting of acetic acid, water and CCl2 to give a compound expressed by formula IV, which is reacted with a compound expressed by formula V in the presence of a base such as diethylamine in a solvent such as DMF using dichlorobis(triphenylphosphine)palladium (II) and CuI as a catalyst to provide the compound expressed by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel fluorotolane-based nematic liquid crystal compound useful as an electro-optical display material.

[Conventional technology]

The currently mainstream liquid crystal display cell is a TN cell, which is a type of field effect cell. In this TN type cell, Mol-Cryst,
As reported in Llq, Crymt, 6345 (1981), the next step is to reduce the refractive index of the liquid crystal material filled in the cell to prevent the occurrence of interference fringes on the cell surface that would impair the appearance of the cell. Anisotropy (Δn) and cell thickness d
) μm must be set to a specific value. In a practically used liquid crystal display cell, the value of Δn-d is 0.
It is set to either 5, 1.0, 1.6 or 2.2. Since the value of Δn-d is set to a constant value in this way, the value of d can be made small by using a liquid crystal material with a large value of Δn. When the value of d becomes small,
The response time (τ) becomes small according to the well-known relational expression ταd2. Therefore, a liquid crystal material with a large value of Δn is
It is an extremely important material for producing liquid crystal display cells with fast response speed and no interference fringes. On the other hand, most of the liquid crystal materials that can be put to practical use are usually prepared by mixing several or more components, each consisting of a compound that has a nematic phase near room temperature and a compound that has a nematic phase above room temperature. . Most of the above-mentioned mixed liquid crystals currently in practical use are at least -30°C to +65°C.
However, with the diversification of applied products for liquid crystal display cells, there is a demand for liquid crystal materials that extend the nematic liquid crystal temperature range to higher temperatures. Strangely enough, my friend, a nematic liquid crystal compound with a high nematic phase-isotropic liquid phase (NT) transition temperature is considered essential.

The inventors have developed a large Δn and high N to meet these demands.
Another proposal was made for a nematic liquid crystal containing -f transition temperature (Japanese Unexamined Patent Publication No. 152427/1983).

However, this compound has a crystalline phase-nematic phase (C-N).
It has the disadvantage of a high transition temperature and poor compatibility with the nematic mixed liquid crystals currently in use.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is that Δn is large and N
An object of the present invention is to provide a novel nematic liquid crystal compound having a high -1 transition temperature, a low C-N transition temperature, and good compatibility with the nematic mixed liquid crystals generally used at present.

[Means to solve all problems]

In order to solve the above-mentioned problems, the present invention aims to solve the above-mentioned problems by using the general formula: ) arrangement. ] The above problems were solved by providing a compound represented by the following.

The compound of formula (1) according to the present invention can be produced according to the following production method.

In the first step, the compound of formula (II) is reacted with magnesium powder in a solvent such as all anhydrous tetrahydrofuran.
The compound II) is produced.

In the second step, the compound of formula (m) is reacted with 4-n-alkylcyclohexanone of formula (■), and then decomposed with hydrochloric acid or the like to produce a compound of formula (V).

The third step is dehydration of compound 1 of formula (V) in a solvent such as toluene over an acidic catalyst such as p-t/l/enesulfonic acid to prepare a total compound of formula (M).

Fourth Step The compound of formula (M) is catalytically reduced with a hydrogenation catalyst such as Raney nickel in a solvent such as ethanol to produce a compound of formula (■).

Fifth step: A compound of formula (■) is reacted with periodic acid dihydrate of iodine in a mixed solvent consisting of acetic acid, water and carbon tetrachloride to produce a compound of formula (■).

Step 6: The compound of formula (■) is prepared in the presence of a base such as diethylamine in a solvent such as N,N-dimethylformamide using -cyclolobis(triphenylphosphine)palladium(n) and g1M iodide as a catalyst. ,formula(
The compound of formula (1) according to the present invention is entirely produced by reacting with the compound of (ii).

Table 1 lists the transition temperatures of representative compounds of formula (1) thus produced.

1st table grave RR' transition temperature ('C)I
n-"C3H, -n-C4) 1.-48(-C
AN) 186 (N T ) ← In the table, C represents a crystalline phase, N represents a nematic phase, and ■ represents an isotropic liquid phase.

The compound according to the invention according to the formula (2) is a nematic liquid crystal compound having a weakly positive or weakly negative dielectric anisotropy and can therefore be used, for example, in a mixture with other nematic liquid crystal compounds having a negative dielectric anisotropy. It can be used as a material for dynamic light scattering type display cells, and can be used as a material for field effect type display cells in a mixture with other nematic liquid crystal compounds having positive or negative dielectric constant anisotropy. Thus, preferred representative examples which can be used in admixture with the compound of formula (I) include □4-substituted benzoic acid 4'-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4'-a substituted phenyl ester, 4
-Substituted cyclohexane car? 4'-R-substituted piphenyl ester of benzoic acid, 4-(4-substituted cyclohexanecaryloxy)benzoic acid 4'-substituted phenyl ester,
-fiil cyclohexyk) benzoin H4' -fi
1m phenyl ester, 4-(4-substituted cyclohexyl)benzoic acid 4'-substituted Schiff tetrahexyl ester, 4-substituted 4'-substituted biphenyl, 4-substituted phenyl-4'-substituted cyclohexane, 4-substituted 4'-substituted terphenyl,
4-substituted piphenyl 4'-substituted cyclohexane, 2-(
Examples include 4-substituted phenyl)-5-substituted pyrimidine.

Table 2 shows 85% by weight of the base liquid crystal (A), which is currently widely used as a nematic liquid crystal material, and Table 1 shows the following formula (1).
The anisotropy (Δn) of the refractive index (Δn) measured at the qN-1 point is measured for each liquid crystal mixture consisting of 15% by weight of compound 1, and at the ninth point of comparison, the anisotropy (Δn) of the base liquid crystal (A) itself is measured at 7tN. -1 point and posted at Δn1. In addition, the parent liquid crystal consists of and.

Table 2 N-1 point Δn (℃) (-) (A) 54.0 0.0917(A)+41
72.3 0.116 From the data listed in Table 2, it can be seen that the compound of formula (1) can raise the entire N-r point of the parent liquid crystal to a level sufficient for practical use, and Δ
It can be seen that nf can be significantly increased.

The effects of the present invention are also clarified by the following comparative experiments. A known compound of the following formula, which has a chemical structure similar to the compound of formula (1) according to the present invention and was developed for the purpose of increasing the N-1 point and Δnf of mixed liquid crystals, has a C→N transition temperature of 87°C. When this was added to the base liquid crystal (A), the base liquid crystal (A) was added to the base liquid crystal (A).
The solubility of A) at -30°C is 6. At this time, the N-r point of the mixed liquid crystal is 62.1'C and Δn is 0.
It was 101.

On the other hand, one of the compounds according to the present invention, that is, the compound of the formula, has a low C-N transition temperature of 48°C, and its solubility in the base liquid crystal (A) at -30°C is 14%, which is a 6-point ratio. The Nr point of the mixed liquid crystal at this time was 71.0°C and Δn was 0.114.

From these facts, the compound of formula (1) according to the present invention has a lower C-N transition temperature than typical known similar compounds, and can be added in large amounts to the base liquid crystal, resulting in a lower N-r point. It will be understood that Δni can be significantly increased.

Example 1 m-bromofluorobenzene 40.0 j! (0,2
29 mol) of anhydrous tetrahydrone run, and this solution was dissolved in magnesium powder 6.10.9 (0,
251 g atom) K was added dropwise at 20 to 30°C with stirring, and then reacted for 2 hours at room temperature (25°C) to give 3
- Source of fluorophenylmagnesium bromide solution.

Next, in this solution, 29.1 # (0,208 mol) of 4-n-propylcyclohexanone was dissolved in 87% of anhydrous tetrahydrofuran, and the solution was heated to 5 to 1 ml with stirring.
After the dropwise addition at 0°C, the mixture was further reacted at room temperature (25°C) for 3 hours. The reaction solution was added to cold dilute hydrochloric acid with stirring to make it acidic, and then the reaction product was extracted with toluene. The extract was washed with water and dried. The toluene was distilled off from this solution to obtain the crude product 54 of the following compound. , 9.9? Nine points.

The crude product was dissolved in 500 d of sonic toluene, and 0.500 d of p-toluenesulfonic acid l hydrate (2,
After adding 63 mmol), the mixture was allowed to react at reflux temperature for 5 hours while stirring.

After cooling the reaction solution, the toluene layer was washed with water, dried, and the toluene was distilled off from the solution. The obtained original reaction product was separated and purified by vacuum distillation, and the following compound 33, OI! (0
, 150 mol) was obtained as follows.

Yield: 72.1% Next, 33.0 g (0,150 mol) of this compound was dissolved in ethanol 160-, and a catalytic amount of Raney was added to this solution.
Nickel gold added, under pressure (3.0 kg/cm2 or less),
The entire hydrogenation reaction was carried out at room temperature (25°C).

After the reaction, the catalyst was filtered and ethanol was distilled off from the mother liquor to obtain 33.0 gk of a crude product containing the following compound.

Dissolve this crude product in 9132ml of total vinegar, and add 2ml of water to this solution.
6m, periodic acid dihydrate 9.401 (0,041
2 mol), iodine 19.111 (0,0752 mol),
20w1ly of carbon tetrachloride was added, and the mixture was allowed to react at reflux temperature for 25 hours while stirring. After cooling the reaction solution, add acidic sodium sulfite aqueous solution to remove excess iodine, further dilute with water, and extract the reaction product with carbon chloride. After washing the extract with water and drying, the reaction product obtained by completely distilling off carbon tetrachloride from this liquid was vacuum distilled to obtain 13.9 g of a crude product of the following compound Kanakura.

This crude product was dissolved in 8.24 mmol of diethylamine, and to this solution was added dichloro-bis(triphenylphosphine)nogradium (It) 2819 (0.040 mmol) and cuprous iodide 7611F (0.40 mmol). ), and while stirring these at room temperature, a solution of p-n-butylphenylacetylene 6,3 lI (0,040 mol) dissolved in 20 m of N,N-dimethylformamide was added dropwise, and the mixture was stirred at room temperature for 24 hours. Leave it alone and move on. This reaction solution was added to a dilute aqueous solution of hydrochloric acid for gold coating to make it acidic, and then the reaction product was extracted with toluene, the extract was washed with water, and after drying, the toluene was distilled off from this solution to obtain the reaction product.几.

The resulting nine reaction products were separated and purified by silica glu column chromatography, and purified by recrystallization from n-hexane to obtain the following compound 7.41 (0,020 mol) in total.

Yield 13T transition temperature 48°C (C-+N) 186°C (N;:r) [Effects of the invention] The novel nematic liquid crystal compound of the present invention has a high transition temperature for N-, and has a large 4-portion. By mixing it with liquid crystal mixtures that are currently in practical use, N-1
The transition temperature and Δn can be increased. Furthermore, compared to known structurally similar compounds, the mixed liquid crystal has a lower C-N transition temperature and has a higher solubility at low temperatures in liquid crystal mixtures currently in practical use, and has a higher N-1 transition temperature and Δni. It can be made.

Claims (1)

[Claims] ▲ Numerical formulas, chemical formulas, tables, etc. - equatorial) arrangement. ] A compound represented by