JPS5936643A - 3,4-dichlorobenzoic acid 4-(trans-4'-(trans-4"-alkylcyclohexyl) cyclohexyl)phenyl ester - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R is H or 1-10C alkyl). EXAMPLE:3, 4-Dichlorobenzoic acid 4-[ trans-4'-( trans-4''-propylcyclohexyl )-cyclohexyl]phenyl ester. USE:A liquid crystal substance exhibiting a liquid crystal phase over a wide temperature range, having high clear point, and nevertheless, low viscosity and positive dielectric anisotropy. When the compound is used as a component of a liquid crystal composition, the clear point of the composition can be raised without increasing the viscosity of the composition nor too much affecting the threshold voltage and saturation voltage. PROCESS:The compound of formula I can be prepared by (1) reacting 4-bromoanisole of formula II with metallic Mg, (2) reacting the product with 4-(trans-4'- alkylcyclohexyl)cyclohexanone to obtain the compound of formula III, (3) subjecting the compound successively to dehydration, reduction, and demethylation, and (4) reacting the resultant compound of formula IV with 4-dichlorobenzoic acid chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel liquid crystal material exhibiting a liquid crystal phase over a wide temperature range and having positive dielectric anisotropy, and a liquid crystal composition containing the same.

Display elements using liquid crystals have come to be widely used in watches, calculators, etc. This liquid crystal display element utilizes the properties of optical anisotropy and dielectric anisotropy of liquid crystal materials, and liquid crystal phases include nematic liquid crystal phase, smectic liquid crystal phase, and cholesteric liquid crystal phase. The one used is the one most widely put into practical use. In other words, there are various types such as tiTN (twisted nematic) type, DS type (dynamic permissive type), guest-host type, DAP type, etc.
The properties required of the liquid crystal materials used for each type are different. However, in any case, it is desirable that the liquid crystal substances used in these display elements exhibit a liquid crystal phase over as wide a range as possible in nature, but there is currently no single substance that satisfies such conditions. Currently, products that can be put to practical use are obtained by mixing several liquid crystal substances or non-liquid crystal substances. In addition, these materials must of course be stable against moisture, light, heat, air, etc., and the threshold voltage and saturation voltage necessary to drive the display element must be as low as possible, and the response must be as low as possible. In order to increase the speed, it is desirable that the viscosity be as low as possible. By the way, in order to widen the liquid crystal temperature range toward high temperatures, it is necessary to use a liquid crystal substance with a high melting point as a component, but liquid crystal substances with a high melting point generally have a high viscosity, so the liquid crystal composition containing it also has a high viscosity. As a result, the response speed of liquid crystal display elements that can be used at high temperatures, for example, up to about 80° C., particularly at low temperatures, tends to be significantly slow. However, the present inventors have arrived at the present invention, a liquid crystal material f1: glossy, which exhibits a liquid crystal phase over a wide temperature range, has a high clearing point, and has a low viscosity.

That is, the present invention provides 3,4-dichlorobenzoic acid-4-(trans-4'-( ) lance-4''-alkylcyclohexyl)cyclohexyl]phenylnisder and a liquid crystal composition containing the same.

The compounds of the present invention have a high clearing point.
) lance-4'-() lance-4''-:/' o hirucyclohexyl)cyclohexyl] phenyl ester O
C-8 point tri 145'C%SN point, 1185°
The C,N-1 point exhibits a liquid crystal phase in a wide temperature range of 800°C or higher, and by adding it as a component of the composition, the clearing point can be raised without increasing the viscosity of the liquid crystal composition. . Further, although the dielectric anisotropy value of the compound of the present invention is about +2, it does not change the threshold voltage and saturation voltage of the composition so much. It also has good stability against moisture, heat, light, etc.

Next, the method for producing the compound of the present invention will be described. First, 4-promoanine and metal magnesium are reacted to form 4-methoxyphenylmagnesium bromide, which is then converted into 4-methoxyphenylmagnesium bromide.
4-methoxy-(1'-hydroxy-4'-()trans-4" −
alkylcyclohexyl)cyclohexyl]benzene. This was then dehydrated using potassium hydrogen sulfate as a catalyst to give 4-methoxy-(4'-()lans-4"-alkylcyclohexyl)cyclohexen-t'-yl]benzene. This was then treated with a Raney nickel catalyst in an ethanol solvent. 5- 4-methoxy-(4'-()lans-4''-alkylcyclohexyl)cyclohexyl]benzene is obtained when reduced at normal pressure and 30°C.

Since this is a mixture of trans and cis isomers, it is recrystallized from ethanol and 4-methoxy-[trans-4'-(
) lance-4"-argylcyclohexyl]cyclohexyl]benzene is obtained. It is then demethylated with hydrobromic acid to yield 4-[trans-4'-()lance-4"-alkylcyclohexyl)cyclohexal]fux /-le is obtained. In the presence of pyridy a.

React with 4-dichlorobenzoic acid chloride to obtain the desired 8.4
-Dichlorobenzoic acid-4-[trans-4'-()trans-4"-alkylcyclohexyl)cyclohexyl]
Phenyl ester was produced.

The above is expressed as a chemical formula: 6-(1) Hereinafter, the manufacturing method and usage examples of the compound of the present invention will be explained in more detail with reference to Examples.

Example 1 (8,4-dichlorobenzoic acid-4-(trans-4'-()trans-4"-propylcyclohexyl)
Production of cyclohexyl phenyl ester] Place three pieces of magnesium 1.2y (0,049 mol) in the form of 4-bromoaniso-A-9,21
(0,049 mol) dissolved in tetrahydrofuran (80 wt) was heated to a reaction temperature of 80 to 85° in a nitrogen stream.
( ), and slowly dripping with stirring, the reaction will occur, and in 8 hours the magnesium will dissolve and become homogeneous to produce p4-methoxyphenylmagnesium bromide. ) 10.9F (0,049 mol) of cyclohexene was dissolved in tetrahydrofuran to make 50*t and reacted with reaction 11.
．． Drop as quickly as possible while keeping the A degree at b~10°0. After dropping, raise the temperature to 86°C'' for 80 minutes.
! Add 50 ytt i of 8N hydrochloric acid.

The reaction solution was placed in a separatory funnel and extracted three times with 200ml of toluene.The combined toluene layer was washed with water until the washings became neutral, and the toluene was distilled off from -C under reduced pressure. The substance is 4-methoxy-(1'-hydroxy-4'-(
) lance-4''-propylcyclohexyl)cyclohexyl] benzene, add 6 g of potassium hydrogen sulfate, and dehydrate at 160°C for 2 hours in a nitrogen stream. After cooling 2
After adding 00d of toluene, potassium hydrogen sulfate is removed separately, and the toluene layer is washed with water until the washing solution becomes neutral. The toluene was then distilled off under reduced pressure, and the remaining oil was recrystallized with ethanol to obtain 4-methoxy-(4'-()lance-4"-propylcyclohexyl)cyclohexene-1'l)benzene. .All fik obtained here
7. of Raney nickel catalyst 1. Dissolve in 120g of ethanol along with Of and perform catalytic reduction at normal pressure 50°C.
500 ml of hydrogen was absorbed. The catalyst is sent door to door and recrystallized as is. Since the obtained product is a mixture of cis and trans forms, we further recrystallize it with ethanol.
Isolate the trans isomer.

This is 4-methoxy-[trans-4'~(trans-
4"-Propylcyclohexyl)cyclohexyl]benzene was obtained in an amount of 28 g and a yield of 18%.

Reflux 15F with 200 ml of hydrobromic acid (47%) and 200 g of acetic acid for 20 hours. 17 After completion of the reaction 5.
Add 0.00 ml of water and filter the precipitated crystals. After thoroughly washing with water, it was recrystallized from an acetone-ethanol mixed solvent. This is 4-[trans-4'-(
) lance-41-pentylsifhexyl) cyclohexyl phenol.

Yield 11f, yield +<77%. This also shows a liquid crystal phase,
Its C-f (m point is 195°C, S m N point is 20°C
2.5°C, N-1 point is 20? -8'''C.

Ill like this! The constructed 4-[trans-4'-(
To a solution of 1f of trans-41-pentylcyclohexyl (cyclohexyl)phenol dissolved in 80 parts of pyridine, 1 g of 8,4-dichlorobenzoic acid chloride was added, and the mixture was allowed to stand overnight. Add 200 yil of toluene and remove the toluene layer using a separatory funnel to 6NJf! Wash with water until neutral, then with 2N caustic soda solution and finally with water.

After drying it over anhydrous sodium sulfate, the 1.luene layer was distilled off under reduced pressure. When the precipitated crystals are recrystallized from ethanol, the desired 8.4-dichlorobenzoic acid-4-(trans-4'-()trans-4"-propylcyclohexyl) is obtained.
[cyclohexyl]f-10-enyl ester was obtained. Yield 0.8F, yield 51%. Also, the C-8m point is 145.0°C, and the Sm-N point is 185°C.
．． 0°C, and the N-I point was 800°C or higher.

Hereinafter, 4-(trans-4'-(trans-4"-propylcyclohexyl)cyclohexanone on the upper side has another alkyl group in its place)
The following compound can be produced in exactly the same manner except that ()lance-4''-alkylcyclohexyl)cyclohexanone is used.

8.4-dichlorobenzoic acid [-4-()trans-4'-cyclohexylcyclohexyl)7enyl ester, 3.4-dichlorobenzoic acid-4-(trans-4'-(
) trans-4"-methylcyclohexyl) cyclohexyl] phenyl ester 8.4-dichlorobenzoic acid-4-(trans-4'-(
)7ysu-4"-ethylcyclohexyl)cyclohexyl]phenyl ester8.4-dichlorobenzoic acid-4-[trans-4'-(
trans-4”-butylcyclohexyl)cyclohexyl]phenyl ester, C-8m point 1 B 7.1°Q
, 8m-N point 197.5℃, N-I point g o o ”c
that's all.

8.4-Dichlorobenzoic acid-4-(trans-4'-(
) lance-4"-pentylcyclohexyl)cyclohexyl]phenyl ester, 8,4-dichlorobenzoic acid-
4-[trans-4'-()trans-4"-hexylcyclohexyl)cyclohexyl]phenyl ester, 8
．． 4-dichloroamine, lLf acid-4-() lance-4'
-(+-lance-4"-hebutylcyclohexyl)cyclohexyl]phenyl ester, 8,4-dichlorobenzoic acid-,4-f)synx-4'-():7ns4"
-octylcyclohexyl)cyclohexyl]phenyl ester, 8.4-dichlorobenzoic acid-4-(trans-4'-()trans-4"-nonylcyclohexyl)cyclohexyl]phenyl ester, 8.4-dichlorobenzoic acid- 4-[trans-4'-(
) lance-4"-decylcyclohexyl]cyclohexyl]phenyl ester.

Example 2 (Usage example) Trans-4-propyl-(4'-cyanophenyl)cyclohexane 28% Trans-4-pentyl-(4'-cyanophenyl)cyclohexane 42% Trans-4-hebutyl-(4'-cyano The N-I point of a liquid crystal composition having a composition of 80% (phenyl)cyclohexane is 52°C. When this liquid crystal composition was sealed in a TN cell (twisted nematic cell) with a cell thickness of 10 μm, the operating threshold voltage was 1.5.
8V, and the saturation voltage was 2.12■. Also, the viscosity is 20°
It was 28 cp in C.

To 97 parts of this liquid crystal composition, 8 parts of 8,4-dichlorobenzoic acid-4-[trans-4'-(tone-4''-propylcyclohexyl)cyclohexyl]phenyl ester prepared in Example 1 was added. The N-1 point of the liquid crystal composition was 60'0, and when this was made into a TN cell similar to the above, the threshold voltage was 1.55.
V, the saturation voltage was 2.14 V.

The viscosity was 28 cp at 20°C.

that's all 14-

Claims (2)

[Claims] (1) 8,4-dichlorobenzoic acid-4-[trans-4'-()trans-4''- Alkylcyclohexyl)cyclohexyl]7 enyl ester. (2) 8,4-dichlorobenzoic acid-4-[trans-4'-()trans-4''- A liquid crystal composition containing at least one type of alkylcyclohexyl]cyclohexyl]7enyl ester.