JPH03123749A - Ether threshold value voltage-lowering agent - Google Patents

Abstract

NEW MATERIAL:A compound of formula I [R is linear chain 1-5C alkyl; the cyclohexane ring has a trans (equatorial-equatorial) configuration; X is F or H]. EXAMPLE:A compound of formula VIII. USE:A threshold value voltage-lowering agent useful as a material for preparing liquid crystal display cells responding at high speeds and driven at low voltage, capable of lowering the viscosity of mixed liquid crystals and of effectively dropping the threshold value voltage and having excellent solubility in general mixed liquid crystals. PREPARATION:A compound of formula II is reacted with methoxymethyl triphenyl phosphonium chloride and the resultant compound of formula III is treated with hydrochloric acid to prepare a compound of formula IV. The compound of formula IV is reacted with the above-mentioned chloride and the resultant compound of formula V is treated with hydrochloric acid to produce the compound of formula VI. The compound of formula VI is reacted with the avove-mentioned chloride to give the compound of formula VII, which is reduced in the presence of Raney nickel catalyst to provide the compound of formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel ether-based threshold voltage lowering agent useful as an electro-optical display material.

[Prior art] M-Shut (M, 5) is a typical liquid crystal display cell.
chadt) etc. (APPLIED PHYSICS L
HTTER3lfi.

127-128 (1971)) or the field effect mode cell proposed by G. H. Beilmeier (G.

H, Heilmeier) et al.
OF THE 1. E.J., E.

(1968)) or the dynamic light scattering cell proposed by G. H. Heilmeier et al. [APPL
IED PHYSICSLETTERS landlord, 91
(1968) “L or D.L.White” etc. (JOURNAL 0FA
PPLIED PHYSICS45.4718 (1
There is a guest-host type cell proposed by 974)).

These liquid crystal display cells are required to have various characteristics, but high-speed response and low threshold voltage (Vth) are particularly important characteristics required. A liquid crystal display cell having a low threshold voltage can be driven at a low voltage.

The equivalent time (τ) is proportional to the viscosity (η) of the liquid crystal material (τ
Therefore, if a liquid crystal material with low viscosity is used, a liquid crystal display cell with high-speed response can be manufactured.

[Problem to be solved by the invention]

At present, excellent viscosity reducing agents used for this purpose include the compounds represented by the following.

However, although the above compound (a) lowers the viscosity, it has the drawback of increasing the threshold voltage.

The problem to be solved by the present invention is to provide a novel compound that, when added to a parent liquid crystal, effectively reduces the viscosity and threshold voltage of the parent liquid crystal.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention is directed to the general formula: Represents F or H. ] Provides a compound represented by:

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

... (■) [In the above reaction formula, R represents a linear alkyl group having 1 to 5 carbon atoms, the cyclohexane ring has a trans (equatorial-equatorial) configuration, and X represents F or H. ] Step 1 - A compound of formula (n) is reacted with methoxymethyltriphenylphosphonium fluoride in t-butyl methyl ether to produce a compound of formula (II[).

Step 2 - Treating the compound of formula (I) with hydrochloric acid in tetrahydrofuran to produce the compound of formula (IV).

Step 3 - A compound of formula (IV) is reacted with methoxymethyltriphenylphosphonium chloride in butyl methyl ether to produce a compound of formula (V).

Step 4 - A compound of formula (V) in tetrahydrofuran;
Treatment with hydrochloric acid produces a compound of formula (Vl).

Step 5 - The compound of formula (Vl) is also reacted with methoxymethyltriphenylphosphonium chloride in monobutyl methyl ether to produce the compound of formula (■).

Step 6 - Compound of formula (■) is dissolved in Raney acetate in ethyl acetate.
Compound (1) is produced by performing catalytic reduction using nickel as a catalyst.

Table 1 lists the melting points of representative compounds of formula (I) thus produced.

Table 1 The compounds of formula (I) according to the present invention do not exhibit a nematic phase, but can be used, for example, in a field-effect display cell in a mixture with other nematic liquid crystal compounds having positive or negative dielectric constant anisotropy. It can be used as a material.

Thus, preferred representative examples which can be used in admixture with compounds of formula (I) include, for example, 4-substituted benzoic acid 4'-substituted phenyl esters, 4-substituted cyclohexanecarboxylic acid 4'-substituted phenyl esters, , 4-substituted cyclohexanecarboxylic acid 4'-111 biphenyl ester, 4-(4-substituted cyclohexanecarbonyloxy)benzoic acid 4'-fta phenyl ester, 4-(4-substituted cyclohexanecarbonyloxy)benzoic acid 4'-fta phenyl ester,
-substituted cyclohexyl)benzoic acid 4'-substituted phenyl ester, 4-(4-substituted cyclohexyl)benzoic acid 4'
-Substituted cyclohexyl ester, 4-1m4'-substituted biphenyl, 4-substituted phenyl-4'-substituted cyclohexane, 4-substituted 4"-substituted terphenyl, 4-substituted biphenyl 4"-111A cyclohexane, 2-(4'-substituted cyclohexane) 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 driving characteristics, and 10% by weight each of the compounds Nα1 and Nα2 of formula (I) shown in Table 1. The viscosity and threshold voltage (Vth) measured for each mixed liquid crystal consisting of are posted for comparison, and for comparison, the base liquid crystal (A) is 90% by weight and is generally used as an excellent viscosity reducing agent. The viscosity and vth measured for a mixed liquid crystal consisting of the following compound (a) used and 10 weight of each of the following compound (b) having a similar structure to compound Nα1 are listed. The base liquid crystal (A) is as shown in Table 2, and the compound (a) and compound (b) are represented by the following formula.

It can be seen from Table 2 that the compound of formula (1) lowers the viscosity of the base liquid crystal (A) and significantly lowers the threshold voltage.

This superiority is particularly clear in the reduction of threshold voltage when compared with compound (a), which is commonly used as a viscosity reducing agent, and compound (b), which has a similar structure to compound Nα1.

Example 1 Methoxymethyltriphenylphosphonium chloride 4
4.5 g (0.13 mol) in 150 mI of t-butyl methyl ether! , and while maintaining the internal temperature at -10°C, add 16.8 g of potassium-butoxide (0,1
5 mol) within 5 minutes, stirred at the same temperature for 10 minutes, and then continued stirring at room temperature for 1 hour. Next, reduce the internal temperature to 11
While keeping the temperature at 0℃, (0.1 mol) of tetrahydrofuran 1tE50n+f was added dropwise over 5 minutes, and at the same temperature, 1tE50n+f was added dropwise.
After stirring for 0 minutes, stirring was continued for 1 hour at room temperature.

After the reaction is complete, add 150,111 liters of water to the reaction solution. After stirring for 10 minutes, the mixture was extracted twice with 150 mf of ethyl acetate.

After washing and drying the extract, the solvent was distilled off under reduced pressure. A mixed solvent of n-hexane:toluene (1:1) was added to the obtained residue, and after stirring for 30 minutes, triphenylphosphine oxide was filtered. Separated. The filtrate was purified using a silica gel column to obtain 20 g (0.09 mol) of the following compound.
I got it.

20g of the above compound and 100ml of tetrahydrofuran
The mixture was dissolved in a mixed solvent of 20 mf of hydrochloric acid and heated under reflux for 1 hour. After the reaction was completed, 200 ml of water was added to the reaction solution, and the mixture was extracted twice with 150 mf of ethyl acetate. After washing the extract with water and drying, the solvent was distilled off under reduced pressure to obtain 16 g of the following compound (0
,078 mol) was obtained.

Methoxymethylphosphonium chloride 44.5g (0
, 13 mol) was suspended in 150 mf of butyl methyl ether, and while maintaining the internal temperature at -10°C, potassium
It was treated with 16.8 g (0.15 mol) of t-butoxide within 5 minutes, stirred at the same temperature for 10 minutes, and then treated with 16.8 g (0.15 mol) of t-butoxide at room temperature.
Stirring was continued for an hour.

Next, the above compound 1 was added while maintaining the internal temperature at -10°C.
A solution of 6 g of tetrahydrofuran (50 mf) was added dropwise within 5 minutes, stirred at the same temperature for 10 minutes, and then continued stirring at room temperature for 1 hour. After the reaction is complete, add 150n+jl of water to the reaction solution! was added and stirred for 10 minutes, then 150 n/! of ethyl acetate was added. Extracted twice. After washing the extract with water and drying, the solvent was distilled off under reduced pressure, and the resulting residue was mixed with n-hexane:toluene (1
: 1) mixed solvent 500nF! After stirring for 30 minutes, triphenylphosphine oxide was filtered off.

The filtrate was purified using a silica gel column to obtain 18 g (0,077 mol) of the following compound.

18g of the above compound was added to tetrahydrofuran 100II+1
and 9% H (/!20mj2) and heated under reflux for 1 hour.Next, 200ml of water was added to the reaction solution, and extracted twice with ethyl acetate 150II+2.The extract was washed with water, dried, and then dissolved in the solvent. was distilled off under reduced pressure to obtain the following compound 1
5 g (0,068 mol) were obtained.

Methoxymethyltriphenylphosphonium chloride 4
4.5 g (0.13 mol) was suspended in 150 IIll of t-butyl methyl ether, and the internal temperature was -i.

Potassium-t-butoxide 16.
8 g (0.15 mol) within 5 minutes and at the same temperature 1
After stirring for 0 minutes, stirring was continued for 1 hour at room temperature. Next, while maintaining the internal temperature at -10°C, 50 tall of a solution of 15 g of the above compound in tetrahydrofuran was added dropwise over 5 minutes, and after stirring at the same temperature for 10 minutes, stirring was continued at room temperature for 1 hour. After the reaction is complete, add 150ml of water to the reaction solution. Add
After stirring for 10 minutes, the mixture was extracted twice with 150 ml of ethyl acetate.

After washing and drying the extract, the solvent was distilled off under reduced pressure. A mixed solvent of n-hexane:toluene (1:l) was added to the resulting residue, stirred for 30 minutes, and triphenylphosphine oxide was filtered off. Then, the filtrate was purified using a silica gel column to obtain 16 g (0,066 mol) of the following compound.

In the same manner as in Example 1, the following compound was obtained.

16g of the above compound was dissolved in 3001I11 of ethyl acetate, and Raney nickel was used as a catalyst, hydrogen pressure was 5kg/
Catalytic reduction was carried out for 10 hours at ci. After the reaction was completed, the catalyst was filtered off, the filtrate was distilled off under reduced pressure, the resulting residue was distilled under reduced pressure, and then purified by recrystallization from methanol to obtain 12 g (0,048 mol) of the following compound. .

Melting point: 27°C Example 2: Melting point: 12°C [Effect of the invention] When the compound (I) according to the present invention is added to a general mixed liquid crystal, it lowers the viscosity of the mixed liquid crystal and lowers the threshold value. It is a compound that can effectively reduce voltage, and it has the characteristic of being extremely soluble in common mixed liquid crystals. Therefore, the formula (I
) are extremely useful as materials for manufacturing liquid crystal display cells with high-speed response and low-voltage operation.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R represents a linear alkyl group having 1 to 5 carbon atoms, and the cyclohexane ring is trans arrangement, where X represents F or H. ] A compound represented by