JPS60155142A - Novel trans-type nematic liquid crystal compound - Google Patents

Abstract

NEW MATERIAL:A compound shown by the formula I (R is 1-9C straight-chain alkyl; X is F, Cl, Br, or CN; cyclohexane ring is in trans configuration). USE:A nematic liquid crystal compound. Having high DELTAn and high N-I transition temperature. PREPARATION:trans 4-n-alkyl-1-phenylcyclohexane is reacted with a compound shown by the formula II and anhydrous AlCl3 in CS2 or nitrobenzene to give a compound shown by the formula III, -CO- is made into -CH(OH)- by the use of a reducing agent, the resultant compound is dehydrated to give a compound shown by the formula IV containing a double bond, bromine is added to the compound, and the prepared compound is reacted with a base (e.g., 1,5-diazabicyco[5,4,0] undecene-5), to give a compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of tolan 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 (MaS) is a typical liquid crystal display cell.
ehadt) etc. [APPLIED PHYSIC8LE
TTER 818, 127-128 (1971)) or the field-effect mode cell proposed by G.H. Beilmeier (
G@HHei1meler) etc. [PROCEEDIN
GOFTHel, E, E, E, 56 1162-117
1 (196B) 1, a dynamic light scattering cell (
dynamic e-scanning mode cell) or G*HH Heilmeie
r) etc. (APPLIED PHYSIC8tgrTER
s 13, 91 (196s)] or D L White etc. [JOUR
NAL 0FAPPLIED PHYSIC845,4
718 (1974)] and the host type cell.

Among these liquid crystal display cells, the one currently mainstream is a TN type cell, which is a type of field effect cell. In this TN type cell, Mo1. C
rys t, Li q.

As reported in Cryst, 63 45 (1981), the anisotropy of the refractive index of the liquid crystal material filled into the cell is used to prevent the generation of interference fringes on the cell surface, which would impair the appearance of the cell. It is necessary to set the product of the cell thickness (Δn) and the cell thickness (d) μm to a specific value. In practically used liquid crystal display cells, the value of Δn is 0.5.1.
0.1. <S or 2.2.

Since the value of Δnod is set to a constant value in this way, Δ
By using a liquid crystal material with a large value of n, the value of %d can be made small. If the value of d becomes small, the response time (
τ) becomes small according to the well-known relational expression of ταd2.

Therefore, a liquid crystal material with a large value of Δn is an extremely important material for manufacturing a liquid crystal display cell that has a fast response speed and is free from interference fringes. On the other hand, most practical liquid crystal materials are prepared by mixing several or more components, usually consisting of a compound that has a nematic phase near room temperature and a compound that has a nematic phase above room temperature. . Many of the above-mentioned mixed liquid crystals currently in practical use are required to have a nematic phase at least over the entire temperature range of -60°C to +65°C.
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. ) Nematic liquid crystal compounds with high transition temperatures are needed.

The compound of formula () according to the present invention has a large Δn and a high N
-I is a novel nematic liquid crystal compound having a transition temperature. Therefore, by mixing the compound of the formula ([) into the base liquid crystal of each building, a practical mixed liquid crystal material having a large Δn and a high N-I transition temperature can be prepared.

The compound of formula (I) according to the present invention can be produced according to the following production method. It has the same meaning as R in each formula (n) to (V) below and/or R and X in each formula ([).

K1 step N-) Lance 4-n-Alkyl-1-phenylcyclohexane is reacted with a compound of formula (II) and anhydrous aluminum chloride in carbon disulfide or nitrobenzene to produce a compound of formula (III).

1g2 Step - The compound of formula (III) prepared in the first step is reacted with a reducing agent such as lithium aluminum hydride in anhydrous ether or anhydrous tetrahydrofuran to prepare a compound of formula (IV).

Sixth step - A dehydrating agent such as potassium hydrogen sulfate is added to the crude compound of formula (IV) produced in the second step, and the compound is heated and dehydrated to produce a compound of formula (V).

Step 4 - Add carbon tetrachloride or chloroform or 1,1.2-) to the compound of formula (v) produced in step 6.
Addition reaction of bromine in a solvent such as lychloroethane is carried out by the formula (
Compound VI) is prepared.

Step 5 - The compound of formula (Vl) prepared in step 4 is dissolved in a 1,5-
Reaction with a base such as diazabicyclo(5,4,01 undecene-5) produces a compound of formula ().

The compound of formula (I) in which X is CN can be prepared by once preparing the compound of formula (I) in which X is Br, and then reacting this compound with cuprous cyanide in a solvent such as N,N-dimethylformamide. It can also be manufactured by

The transition temperature of the compound of formula ([) thus produced is the first
Listed in the table.

Table 1 I n-C, H7--CN'+ 53℃ (C-+N)
265°C (NgI)2 n-C, H7--Br 15
5℃(C-)N) 221℃(NgI)3 n-C,H
7--C1141℃ (C-+N) 219℃ (I to 1"
)4 n-C,H,--F 90℃(C-+N) 1
89℃ (N loe) 5 C, H, -CN 135℃ (C-
+N) 250'C(NzI)6C,H,-Br136
℃(C-)N) 209℃(NOI)7 C,H,-C
6124℃ (C-+N) 207℃ (NgI) In the formula, C
represents a crystalline phase, N represents a nematic phase, and N represents an isotropic liquid phase.

The compound of formula (I) according to the invention is a nematic liquid crystal compound with weak negative dielectric 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, representative preferred examples that can be used in combination with the compound of formula ([) include, for example, 4,4'-substituted benzoic acid phenyl ester, 4,4'-substituted cyclohexanecarboxylic acid phenyl ester, 4.4'-substituted cyclohexanecarboxylic acid biphenyl ester, 4(4-
Substituted cyclohexanecarbonyloxy)benzoic acid 4'-
Substituted phenyl ester 4(4-substituted cyclohexyl)benzoic acid 4'-substituted phenyl ester, 4(4-substituted cyclohexyl)benzoic acid 4'-substituted cyclohexyl ester, 4.4'-biphenyl, 4.4'-phenylcyclohexane, Examples include 4.4'-M-substituted terphenyl, 4.4'-biphenylcyclohexane, and 2 (4'-substituted phenyl)5-substituted pyrimidine.

Table 2 shows 90% of the base liquid crystal (A), which is currently widely used as a nematic liquid crystal material with excellent time-division driving characteristics, and compounds of the formulas ([) /I61, /162, shown in Table 1,
The N-I point and refractive index anisotropy (Δn) measured for each mixed liquid crystal consisting of 10% by weight of each of /166, 4, 5.7166s and 47.7168 are displayed for comparison. N-I measured for the host liquid crystal (A) itself in
The points and Δn are displayed. The parent liquid crystal is as follows: Point N-I in Table 2 Δn (A) 54.0 C1,0917 (A)+41 74.9 0.116 (A)+42 70.4 0.115 (A)+43 70. 2 0.114 (A)+7g64 67.10.111(A)+716
5 75.2 0.116(A)+/I66 69.1
0.115 (A) + 47 68.9 0.115 (A) + 48 66.2 0.110 From the data listed in Table 2, it is clear that the compound of formula (I) can reach the N-I point of the base liquid crystal sufficiently for practical purposes. Raise it to a maximum of Δ
It can be seen that n can be increased significantly.

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 used for the purpose of increasing the N-I point of the mixed liquid crystal was added to the above-mentioned mother liquid NA) of various types. 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 thus obtained, the respective NI points and Δn were measured. Based on these measurement results, the first
The relationship between the KN-1 point and the amount added is shown in Figure KN-1, and the relationship between the 7 points and the amount added is shown in Figure 2.

From these facts, it can be understood that the compound of formula (I) according to the present invention can significantly increase the N-I point and Δn of the parent liquid crystal as compared to typical known similar compounds.

In an example, anhydrous aluminum chloride 24.0 d in carbon sulfide 250 d.
9 (1180 mol), and while heating under reflux, trans-4-furopyru-1-phenylcyclohexane 30
．． A mixture of 1 (0.15 mol) and 4-bromo-phenylacetic acid chloride 35Ii (0.15 mol) was added dropwise.

After heating under reflux for 1 hour, carbon disulfide was distilled off, and the mixture was added to ice water and stirred at 60°C for 1 hour. Next, extract with toluene, wash with water, dry, and distill off toluene, then ethanol-
Recrystallize and purify with toluene (2:1) to obtain 55 g of the following compound.
(0,088 mol) was obtained.

This compound was dissolved in anhydrous tetrahydrofuran and 4.00,9 lithium aluminum hydride (0,105 mo
1) and 150 ml of anhydrous tetrahydrofuran.

After reacting for 2 hours at room temperature, 9% HCl 200d and water 2
00d was added, extracted with toluene, washed with water, dried, and the toluene was distilled off. The obtained crystals were dissolved in toluene 3QQa+/, and potassium hydrogen sulfate 2.80# (0,0206m
The water was removed using a decanter, and the mixture was heated under reflux for 1 hour. After the reaction, inorganic substances were filtered off and the product was recrystallized from the filtrate to obtain the following compound 26.8. ? (0.07 mol
) was obtained, and this compound was converted into 1,1,2-4-lichloroethane 150
Bromine 12.51 (0,077
mol) was added dropwise.

After reacting for 1.5 hours, the precipitated crystals were collected by filtration, washed with methanol, and dried. The obtained compound was dissolved in 250 dK of N,N-dimethylformamide, and 511.7 g (0,0
77 mol) was added thereto and heated under reflux for 4 hours. After cooling, water was added, the precipitated crystals were collected by filtration, washed with methanol, and dried.
The following compound 18.9.9 (0,0495 mol) was obtained.

Yield 66.1% Transition temperature 155°C (C→N)22
1°C (NzI) This compound 5.8111 (0,0100 mol) was dissolved in N,N-dimethylformamide 7011, cupric cyanide 1.35.17 (0,015 mol) was added, and the mixture was heated under reflux for 12 hours. . A cold solution of ferric chloride in hydrochloric acid was added, stirred for 0.5 hours, extracted with ether, washed with water, dried, and then recrystallized with ethanol-toluene (1:2) to obtain the desired compound 2.309 ( 0,007
05 mol) was obtained.

Yield 25.5% Transition temperature 156°C (C→N)26
5°C (NiI) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield 54.2% Transition temperature 141°C (C-+N)2
19°C (NiI) Example 3 The following compound was obtained in the same manner as in Example 1.

Collection 32.7% Transition temperature 90℃ (C-+N) 18
9°C (NiI) Example 4 The following compound was obtained in the same manner as in Example 1. Yield: 22.7
% Transition temperature 135℃ (C-+N) 250℃ (NpI
) Example 5 The following compound was obtained in the same manner as Example 1. Yield: 33.8
% Transition temperature 166℃ (C-+N) 209℃ (NO
I) Example 6 The following compound was obtained in the same manner as in Example 1.

Collection 64.7% Transition temperature 124℃ (C-+N)
207°C (NiI) Example 7 The following compound was obtained in the same manner as in Example 1.

Yield 32.2% Transition temperature 78℃ (σ→N) 179
℃(N mouth I)

[Brief explanation of the drawing]

Figures 1 and 2 show scrap 1, which is one of the compounds according to the present invention.
Relationship between the N-1 point and the amount added, and the N-I point of a mixed liquid crystal obtained by adding each of the compound and the known compound (, ) having a similar structure to the currently widely used base liquid crystal (A) 3 is a chart showing the relationship between the refractive index anisotropy Δn and the refractive index anisotropy Δn. Agent Patent Attorney Katsutoshi Takahashi Figure 1 (A) + (a, 91 - to (Q) gtz (A > Shichishi, 1 force; vs. Iro (Le 4.120 heavy weight% Figure 2 10) 20 (Ana self #3;'ru (phantom If

Claims (1)

[Claims] general formula A compound represented by