JPH04169581A - 1,3-dioxane derivative, liquid crystal composition containing the derivative and liquid crystal display device produced by using the composition - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (m and n are integers satisfying the formulas m>=0, n>=1 and m+n<=8; X is F or CN; Y is H, F or Cl; the configuration of 1,3-dioxane ring is trans). EXAMPLE:Trans-5-Allyl-2-(4'-cyanophenyl)-1,3-dioxane. USE:A liquid crystal display device. PREPARATION:The objective compound of formula I can be produced e.g. by reacting a bromoalkane of formula II (e.g. allyl bromide) with diethyl malonate in the presence of NaOC2H5, reducing the resultant alkenylmalonic acid diethyl ester with LiAlH4 to obtain a 2-alkenylpropane-1,3-diol of formula III, reacting the compound with a substituted benzaldehyde of formula IV (X' is Br or F) and reacting the reaction product with CuCN.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a 1,3-dioxane derivative useful as a component of a liquid crystal composition used in a liquid crystal display device, a liquid crystal composition containing the same, and a liquid crystal composition thereof. The present invention relates to a liquid crystal display device using.

[Conventional technology]

Liquid crystal display devices using nematic liquid crystals include dynamic scattering method, guest-host method, and twisted nematic method (TN).
There are display methods such as , super twisted nematic method (STN), etc., and the device is driven by a static drive method, a dynamic drive method, an active matrix drive method, a two-frequency drive method, and the like. Among these display methods, the dynamic drive TN method is the most popular.
Recently, the dynamic drive STN system and the active matrix drive TN system are rapidly spreading.

The TN type has a small display capacity but is inexpensive, so it is widely used as a display device for calculators, watches, audio equipment, various measuring instruments, etc. Since the STN type and active matrix drive TN type have a large display capacity, they are applied to display devices for personal computers and word processors, and liquid crystal color televisions, and are attracting attention as display devices that will replace CRTs in the future.

Although the characteristics required of the liquid crystal material used in these liquid crystal display devices vary depending on the display method or field of application, the following characteristics are required for all liquid crystal display devices.

(1) Must be non-colored and thermally, optically, electrically and chemically stable.

(2) The nematic liquid crystal temperature range should be around room temperature and as wide as possible.

(3) The threshold voltage (vlh) of the voltage-light transmission characteristics (V-1° characteristics) is low and its temperature dependence is small.

(4) Good steepness (β) of V-1° characteristics.

(5) The viewing angle dependence (α) of the V Io characteristic is small.

(6) Fast electro-optical response speed.

In addition, the relationship between the display capacity of the currently most widely used TN type or STN type time-division drive type liquid crystal display device and the various characteristics listed on the previous page is the temperature dependence of Vlh in (A) and (3). is small.

The β values in (B) and (4) are as small as possible.

The α values in (C) and (5) are as small as possible.

It is known that the display capacity can be increased.

[Problem to be solved by the invention]

Furthermore, it is expected that the demand for TN or STN type liquid crystal display devices with high time division drive method and low voltage drive will increase in the future, and in that case, in addition to (A) to (C), (3) (7) Materials with low V and h are required. However, there is no known compound that satisfies these properties with a single component, and the current situation is to use a liquid crystal composition that is a mixture of a plurality of nematic liquid crystal compounds or similar compounds thereof.

In the future, the main components contained in liquid crystal compositions that will be used to meet this demand include, but these compounds have a large dielectric anisotropy (△ε) and are highly effective in lowering vlh. It had a drawback of large birefringence (Δn) and large α.

Therefore, an object of the present invention is to provide a compound having a large Δε and a small Δn, and another object of the present invention is to provide a compound having a large Δε and a small Δn.Further, another object of the present invention is to provide a compound of the TN type or liquid crystal composition by mixing the compound of the present invention and a conventional liquid crystal composition. An object of the present invention is to provide a liquid crystal composition that can be driven at a low voltage in a high time division driving method in an STN type, and a liquid crystal display device using the same.

[Means to solve the problem]

(Here, m and n are integers satisfying m≧0, n≧1, m+n≦8, X is F or CN5Y represents HlF or CI, and the 1,3-dioxane ring is in the trans configuration.

) 1,3-dioxane derivatives and their 1.3
- A liquid crystal composition containing a dioxane derivative and a liquid crystal display device using the liquid crystal composition (C, H2, -C)
I”CH<82+DingBr (1)(,H2
,,,1-CH-OH-θll:H2-+-rCO(C
OOEth (Seal) (where m and n are m≧
0, n≧1, an integer satisfying box 10≦8, X' is F or Br, Y is HlF or cg, x is F or CN,
When X' is CN and Y is F or Cg, steps 1 to 4;
In other cases, follow steps 1 to 3. ) Compound (I) of the present invention can be produced, for example, according to the scheme. That is, alkenyl diethyl malonate is obtained from bromoalkane and diethyl malonate. This compound is Li
Reduction with AI Ha gives 2-alkenylpropane-1,
3-diol is obtained. Compound (I) of the present invention is obtained from this compound and benzaldehyde having an appropriate substituent.

In addition, when X is CN and Y is F or Cg, X' is Br.
Compound (Vl) is synthesized using benzaldehyde in which Y is F or Cff, and this is cyanated with CuCN to obtain the compound (T) of the present invention.

Next, the method for producing compound (1) of the present invention will be outlined in accordance with the step order. In step 1, alkenyl bromide (n) and diethyl malonate are reacted in ethanol using sodium ethoxide to obtain alkenyl diethyl malonate (III). In step 2, the compound (
Reduction of m) with lithium aluminum hydride in tetrahydrofuran (THF) gives 2-alkenylpropane-1,3-diol (IV). In step 3, compound (rV) and substituted benzaldehyde are subjected to a dehydration reaction in methylene chloride using toluenesulfonic acid (T s OH) as a catalyst to obtain compound (1) of the present invention. Step 4 is a compound where X' is Br and Y is F or CI (Vl
) in N-methyl-2-pyrrolidinone (NMP)
Cyanation with CN provides compounds of the invention where X is CN and Y is F or CN.

The compound (1) of the present invention has large dielectric anisotropy and low birefringence. In particular, compounds where X is CN and Y is F or Cg have very large dielectric anisotropy, and X and Y are F or F. The compound is characterized by extremely low birefringence. Therefore, a liquid crystal composition prepared by appropriately mixing one or more compounds of the compound (I) of the present invention with other liquid crystal compounds or similar compounds thereof has a low electro-optical threshold voltage and low birefringence.

When mixing the compound of the present invention, the following compounds can be considered as components of the base liquid crystal composition, but are not limited to them. Excellent for alkyl groups, alkoxy groups,
alkenyl group, alkoxymethylene group, X is FSCN,
Alkyl group, alkoxy group, alkoxymethylene group or alkenyl group, Y is HSF or CI, m and n are 0 to
It represents an integer of 2, and the cyclohexane ring and 1°3-dioxane ring are in the trans configuration. )ing. Furthermore, the proportion of the compound of the present invention that can be mixed into the base liquid crystal composition is 1
~50% by weight, but when mixed with the compound of the present invention, the nematic-isotropic liquid transition temperature (N
-1 point) is lowered, a range of 3 to 30% by weight is more preferable.

Furthermore, when a liquid crystal composition prepared by appropriately mixing the compound (I) of the present invention with a base liquid crystal composition is injected into the liquid crystal display cell shown in FIG. 1, and its electro-optical properties are measured, it is found that the viewing angle is wide and High time division driving is possible with low voltage. In the figure, a TN type liquid crystal display cell is used, but the same effect can be obtained when an STN type liquid crystal display cell is used. Since the liquid crystal display device of the present invention is capable of high time-division driving at low voltage, it is very useful as a liquid crystal display device for calculators and the like using solar batteries or lithium batteries.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 (Production of compound 1) Method for producing trans-5-allyl-2-(4'-cyanophenyl)-1,3-dioxane.

Step 1 34.5 g of sodium was dissolved in 1500 cm3 of absolute ethanol, 195 g of diethyl malonate and 182 g of allyl bromide were added, and the mixture was refluxed for 10 hours. Ethanol in the reaction solution was distilled off, water was added to the residue, extracted with ether, washed with water, and dried over Na2SO2. Ether was distilled off, and the residue was distilled under reduced pressure (67℃/2
．． 0 mmHg) to obtain 200 g of diethyl allylmalonate.

Step 2 50 g of lithium aluminum hydrite was dispersed in 500 cm 3 of anhydrous tetrahydrofuran, and 200 g of diethyl allylmalonate was added dropwise while stirring. After the dropwise addition was completed, the mixture was refluxed for 5 hours while stirring. Excess L i A and Q H4 in the reaction solution were decomposed with water-containing tetrahydrofuran, hydrochloric acid was added, and the mixture was extracted with ether, washed with dilute hydrochloric acid, and then dried over NaSO4. The ether was distilled off and the residue was distilled under reduced pressure (112°C/4mmHg) to give 2-allyl-1
28.6 g of 3-propanediol was obtained.

Step 32-Allyl-1,3-propanediol5.
6g, 4-cyanobenzaldehyde 6°4g and p-
Dissolve 0.5 g of toluenesulfonic acid in methylene chloride,
A water separator was attached and the mixture was refluxed for 3 hours to remove the generated water. After washing the reaction solution with water, methylene chloride was distilled off, and the residue was recrystallized from a mixed solvent of methanol and water to obtain trans-5-allyl-2-(4'-cyanophenyl)-1.
4.6 g of 3-dioxane was obtained. The phase transition temperature of this compound was measured by DSC and was as follows: 65.1°C C---1→I (Here, C represents a crystal and ■ represents an isotropic liquid.) Example 2 (Production of compound 2) Method for producing trans-5-allyl-2-(4'-fluorophenyl)'-1,3-dioxane.

Step 1.2 2-allyl-1,3-propanediol synthesized in Step 1.2 of Example 1 was used.

Step 32-Allyl-1,3-propanediol5.
6g, 4-fluorobenzaldehyde 6°0g and p
-Dissolve 0.5 g of toluenesulfonic acid in methylene chloride and proceed as in step 3 of Example 1 to obtain 4.8 g of trans-5-allyl-2-(4'-fluorophenyl)-1,3-dioxane. Ta. The phase transition temperature of this compound is D
Measured by SC 28.0°C C-m--→■ Example 3 (Production of compound 3) Method for producing trans-5-allyl-2-(3',4'-difluorophenyl)-1,3-dioxane .

Step 1.2.3 Transform the transformer in the same manner as in Example 2.
5-allyl-2-(3',4'-difluorophenyl)-1,3-dioxane was obtained. This compound was a liquid at room temperature.

Example 4 (Preparation of compound 4) trans-5-allyl-2-(4'-cyano-3'-
A method for producing (fluorophenyl)-1,3-dioxane.

Step 1.2 2-allyl-1,3-propanediol synthesized in Step 1.2 of Example 1 was used.

Step 32 - Allyl-1,3-propanediol and 4
- 20.3 g of bromo-3-fluorobenzaldehyde and 1°Og of p-toluenesulfonic acid were added to 1° of methylene chloride.
00 cm' and carried out in the same manner as in Step 3 of Example 1 to obtain 12 g of 5-allyl-2-(4'-bromo-3'-fluorophenyl)-1°3-dioxane.

Step 45-Allyl-2-(4'-bromo-3'-
Fluorophenyl)-1,3-dioxane 12g5Cu
CN4.7g to N-methyl-2-pyrrolidinone 50cm
' and refluxed for 1.5 hours. The reaction solution was poured into a ferric chloride solution, extracted with chloroform, washed with diluted hydrochloric acid, and then the chloroform was distilled off. The residue was recrystallized from methanol to give trans-5-allyl-2-(4'-cyano-
3'-fluorophenyl)-1,3-dioxane 2.3
I got g. The phase transition temperature of this compound was measured using DSC.43.
9°C C---1→■ Example 5 (Liquid Crystal Composition 1) Commercially available liquid crystal composition ZLI-1565 (manufactured by Merck & Co., Ltd.) 9
A liquid crystal composition A was prepared by mixing 10% by weight of the compound of Example 1 with 0% by weight.

Liquid crystal composition A The N-I point of this liquid crystal composition is 75.9°C, and 80 is 0.1
It was 25.

Example 6 (Liquid Crystal Composition 2) In the same manner as in Example 5, a liquid crystal composition B was prepared by mixing 90% by weight of ZLI-1565 with 10% by weight of the compound of Example 2.

Liquid crystal composition B The N-I point of this liquid crystal composition is 71.1°C, and Δn is 0.1
It was 16.

Example 7 (Liquid Crystal Composition 3) In the same manner as in Example 5, a liquid crystal composition C was prepared by mixing 90% by weight of ZLI-1565 with 10% by weight of the compound of Example 3.

Liquid crystal composition C The N-1 point of this liquid crystal composition is 65.3°C, and Δn is 0.1
It was 05.

Example 8 (Liquid Crystal Composition 3) A liquid crystal composition was prepared in the same manner as in Example 5 by mixing 90% by weight of ZLI-1565 with 10% by weight of the compound of Example 4.

Liquid crystal composition D The N-I point of this liquid crystal composition is 74.2°C, and n is 0.12.
It was 3.

Comparative Example 1 (Liquid Crystal Composition 1) Trans-5 was added to commercially available liquid crystal material ZLI-1569% by weight.
-propyl-2-(4'-cyanophenyl)-1,3
- 10% by weight of dioxane derivative was mixed. The N-1 point of this liquid crystal composition was 79.6°C, and Δn was 0.121.

Comparative Example 2 (Liquid Crystal Composition 2) A liquid crystal composition was prepared in the same manner as in Comparative Example 1 by mixing 90% by weight of ZLI-1565 with 10% by weight of 4-butyl-4'-cyanobiphenyl. The N-I point of this liquid crystal composition is 82.8°C, and Δn is 0. It was 136.

Example 9 (Liquid crystal display device 1) As shown in FIG. 1, an electrode 3 made of a transparent conductive film (for example, an ITO film) is formed on glass substrates 1 and 2, and an alignment agent made of polyimide or the like is applied thereon. Then, the glass substrates 1 and 2 were placed facing each other with the sealant 6 in between to form a liquid crystal cell, and the liquid crystal composition A was injected between the glass substrates. The cell gap is 9 μm, the cell gap is 9 μm, the threshold voltage (V
Ih), viewing angle dependence α and steepness β were measured. Also, using AC dynamic drive, 1/3 bias, 1/3 bias
The voltage margin M at 3 duties was measured. In addition, ■20, Vaslsα, β, and M were defined by the following formula.

V, 1l-vlov, , -V9゜ (here, Vlo, ■,. and v9o are light transmittance 10
．． The voltage at 50 and 9096, T is the temperature, and φ is the viewing angle, and the front was set at 90°. ) The measurement results of these values are Vo 2.03V and α 1.
28, β was 1.42 and M was 9.5%.

Example 10 (Liquid Crystal Display Device 2) Liquid crystal composition B was injected into the liquid crystal cell prepared in Example 9, and V l h, α, β, and M were measured, and the results were as follows.

VIh 2.09Vα
1.29β
1.44M9,7 Example 11 (Liquid Crystal Display Device 3) Liquid crystal composition C was injected into the liquid crystal cell prepared in Example 9, and Vlh, α, β, and M were measured, and the results were as follows. .

V,, 2.03Vα
1.25β
1.43M
9.9% Example 12 (Liquid Crystal Display Device 4) The liquid crystal composition was injected into the liquid crystal cell prepared in Example 9, and the V I b % α, β, and M were measured, and the results were as follows. Ta.

VIb 1.92Vα
1.28β
1.40M 9.8%
Comparative Example 3 (Liquid Crystal Display Device 1) The liquid crystal composition prepared in Comparative Example 1 was injected into the liquid crystal cell prepared in Example 9, and V lh% α, β, and M were measured. The results were as follows. Ta.

V,, 2. IIVα
1,32β
1.43M 8.8%
Comparative Example 4 (Liquid Crystal Display Device 2) The liquid crystal composition prepared in Comparative Example was injected into the liquid crystal cell prepared in Example 9, and vll, α, β, and M were measured, and the results were as follows.

V,, 2.22Vα
1.31β
1,42M 9.0% Although a TN type liquid crystal cell was used in the above embodiment, the same effect can be obtained when an STN type liquid crystal cell is used instead of the TN type.

〔Effect of the invention〕

As described above, it has been revealed that the compound of the present invention has large dielectric anisotropy and small birefringence. Also,
By mixing the compound of the present invention with other liquid crystal compounds or similar compounds thereof, a liquid crystal composition having a low threshold voltage and viewing angle dependence can be obtained, and a TN type or STN type liquid crystal composition using this liquid crystal composition can be obtained. It was confirmed that the liquid crystal display device can be driven at low voltage and in high time division.

Therefore, the compound of the present invention is extremely useful as a basic component of a TN type or STN type liquid crystal composition used for high time division low voltage driving.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a liquid crystal element manufactured in an example of the present invention. 1.2...Glass substrate 3...Transparent electrode film 4... Orientation control layer 5...Polarizing plate 6...Sealing agent that's all Applicant: Seiko Epson Corporation

Claims (3)

[Claims] (1) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (Here, m and n are integers satisfying m≧0, n≧1, m+n≦8, X is F or CN, and Y is A 1,3-dioxane derivative characterized in that it represents H, F or Cl, and the 1,3-dioxane ring has a trans configuration. (2) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (Here, m and n are integers satisfying m≧0, n≧1, m+n≦8, X is F or CN, and Y is 1. A liquid crystal composition containing at least one 1,3-dioxane derivative represented by the formula (1,3-dioxane ring is in trans configuration). (3) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (Here, m and n are integers satisfying m≧0, n≧1, m+n≦8, X is F or CN, and Y is A liquid crystal display device characterized by using a liquid crystal composition containing at least one type of 1,3-dioxane derivative represented by H, F, or Cl, and the 1,3-dioxane ring has a trans configuration.