JPS59148752A - Fluorine-containing cyclohexylbenzoic acid phenyl ester derivative - Google Patents

Abstract

NEW MATERIAL:A 4-(trans-4-substituted-cyclohexyl)-2-fluorobenzoic acid-4-cyanophenyl ester derivative shown by the formula I (R is 1-10C alkyl, or alkoxy). EXAMPLE:4-(trans-4-hexylcyclohexyl)-2-fluorobenzoic acid-4-cyanophenyl ester. USE:A liquid crystal display element substance. Having positive dielectric anisotropy and low viscosity. PREPARATION:3-Fluorobromobenzene shown by the formula II is reacted with magnesium, reacted with a 4-substituted cyclohexanone, and dehydrated. The resultant compound is catalytically reduced, reacted with acetyl chloride, oxidized further, and reacted with p-cyanophenol, to give a compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel liquid crystal material having positive vj electric power tropism and low viscosity, and a liquid crystal composition containing the same.

The liquid crystal display element is liquid, ti! It utilizes the optical anisotropy and di-1M and J4-isotropy of the substance, and depending on its display format, it can be classified into TN type (twisted nematic type), DB type (dynamic scattering type), guest-host type, and DAP type. There are various types of liquid crystal materials, and the properties of the liquid crystal materials used for each type are different. However, it is common for all liquid crystal materials to be stable against moisture, air, heat, light, etc.
There is a need for a material that exhibits a small liquid crystal phase over as wide a temperature range as possible, centering on room temperature. However, at present, there is no single compound that satisfies these conditions, and the current situation is to use liquid crystal compositions obtained by mixing liquid crystal compounds and non-crystalline compounds.

Recently, there has been a demand for liquid crystal compositions that can be driven at low voltages. It is said that a liquid crystal material with a large dielectric anisotropy value or a low viscosity material is suitable for meeting these requirements. The present invention has been made in view of such circumstances.

That is, the compound of the present invention is 4-(trans-4-substituted-cyclohexyl)-2-fluorobenzoic acid- represented by the general formula (in the above formula, R represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms). 4-cyanophenyl ester. Since this compound exhibits a large positive conduction anisotropy and also has a not so large viscosity, it can be used in liquid crystal display elements that can be driven at low voltage by mixing it with other liquid crystal compositions.

Next, a method for producing the compound of the present invention will be described.

First, 3-fluorobromobenzene (1) was reacted with magnesium in tetrahydrofuran to form 3-fluorobenzene magnesium fluoride (■), to which 4-i% cyclohexanone was added and 3-(4-am cyclohexane-
1-ol)fluorobenzene ((2). This is dehydrated using potassium hydrogen peroxide as a catalyst to form 3-(4-II).
t, fluorobenzene (converted-fuclohexen-1-yl) is obtained. This product is catalytically reduced in toluene with a Raney nickel catalyst to obtain 3-(4-cyclohexyl)fluorobenzene (V). This was mixed with F acetyl chloride in the presence of aluminum chloride in carbon disulfide to form 4-(
) lance-4-substituted cyclohexyl)-2-fluoro”
Acetofutonon (Vl) is obtained.

This product was dissolved in dioxane and oxidized with sodium hypobromite to produce 4-(trans-4-substituted cyclohexyl)-
2-Fluoro-amin, tl[m(VB), is produced. This was converted into acid chloride with thionyl chloride and then reacted with P-cyanophenol in the presence of pyridine to obtain the desired 4-(
Trance-4-1! cyclohexyl)-2-fluoroben iFm-4-cyanophenyl ester (Vllll)
can be manufactured.

The above is expressed as a chemical formula as follows.

(1) (1) (2)
(V) 1) BOOI2 (R represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms) The present invention will be explained in more detail with reference to Examples below.

Production of 4-cyanophenyl ester of 3-fluoro-bromobenzene (ftll(4-() lance-4-hexyl-4-hexyl)-2-fluorobandhizoic acid-4-cyanophenyl ester) First, 26.6 f(0,1
52 mol) was dissolved in tetrahydro 7ran 100- and mixed with 3.72 mol (0,152 gram atom) of magnesium in a nitrogen stream and kept at 40-45°C for 2 hours. When the magnesium pieces disappeared, the mixture was cooled, and a solution prepared by dissolving 22.1 F (0.121 mol) of 4-hexylcyclohexanone in 200 ml of tetrahydrofuran was quickly added, and the temperature was maintained at 30° C. or lower. After the dropwise addition, the mixture was refluxed for 2 hours, 3N salt [100] was added thereto, extracted with n-hebutane 250, and liquid separation washing was performed. l5I1. The solution was washed with water until it became neutral, and the combined n-hebutane layers were distilled off under reduced pressure to obtain the remaining oily substance 3-(4-hexylcyclohexan-1-ol)fluorobenzene. To this was added 7f of potassium hydrogen sulfate, and the mixture was dehydrated at 190° C. for 2 hours in nitrogen. After cooling, the potash hydrogen sulfate was separated and washed by adding 200+d of n-hebutane. Rinse with water until the washing solution becomes neutral, and combine.
-Add 3t of anhydrous sodium sulfate to the hebutane layer, leave it overnight, and distill under reduced pressure to obtain the main fraction (160℃/'5''Hr)
Collected. 21.7 F of this product was dissolved in toluene room, 7 f of Raney nickel was added, and catalytic reduction was carried out at room temperature and pressure for 10 hours. After removing the catalyst from F, toluene was distilled off under reduced pressure, and the remaining oil was distilled under reduced pressure. The main distillate is 130~l
41C/2 Hf, which was a mixture of trans and cis forms. This thing 10F carbon disulfide 50
6.2 ft. of aluminum chloride.

Acetyl chloride at 2-5°C with stirring4. Of was added over 10 minutes, and the temperature was gradually raised and kept at 35°C for 2 hours. After cooling, 50% of 6N hydrochloric acid was added and extracted with 100% of toluene. After washing with water and the washing liquid became neutral, the solvent was distilled off under reduced pressure, and red crystallization was performed with ethanol. Obtained crystal ha!
-() lance-4-hexylcyclohexyl)-2-fluoroacetophenone showed a melting point of 51.5°C. 3.1f of this product was dissolved in 50ml of dioxane, and a solution of thorium hypobromite prepared with 4.4t of sodium chloride, 100ml of ice water, and 6.41ml of bromine was added dropwise with stirring at a temperature below 1.0C. The dropping process was completed in about 1 hour, and then heated to 35°C.
Stirring was continued for 2 hours.

After cooling, 31 parts of sodium bisulfite was added, and the mixture was made acidic with 1 part of 100 parts of 3N salt. The precipitate was separated and the residue was recrystallized from salt tR10- to obtain crystals of 4-()lanth-4-hexylcyclohexyl)-2-fluorobenzoic acid.

The nematic clearing point of the crystal was 226°C. Dissolve this product O, IF in 1 Q ml of toluene, and dissolve 1. of was added and reacted at 70°C for 3 hours. Excess thionyl chloride was distilled off under reduced pressure and dissolved in toluene lO-. This solution was shaken and mixed with 10 m of a pyridine solution containing 0.05 f of P-cyazunoenol and left overnight.

This was extracted with 50 g of diethyl ether, and dispersed and washed with 6N-hydrochloric acid and 2N-soluble salt. After washing with water and the washing liquid became neutral, the solvent was distilled off under reduced pressure, and recrystallization was performed with toluene. The ester was obtained, yield ttiO,01t, crystalline point 53.0-56.5C.

It showed a clearing point of 191.5°C.

Examples 2 to 10 The following compounds * were obtained by carrying out the operation according to Example 1, except that another 4-alkylcyclohexanone was used in place of 4-hexylcyclohexanone used in Example 1.

4-()lanth-4-ethylcyclohexynol)-2-fluorobenzoic acid-4-cyanophenyl ester 4-()lanth-4-propylcyclohexyl)-2-
Fluorobenzoic acid-4-cyanophenyl ester 4-()lance-4-butylcyclohexyl)-2-fluorobenzoic acid-4-cya/phenyl ester 4-()lance-4-pentylcyclohexyl)-2 −
Fluorobenzoic (Yl-4-cyanophenyl ester 4-() lance-4-hebutylcyclohexyl)-2-
Fluorobenzoic acid-4-cyanophenyl ester 4-(trans-4-octylcycloxyl)-2-fluorobenzoic acid-4-cyanophenyl ester 4-(trans-4-nonylcyclohexyl)-2-fluoro Benzoic acid-4-cyanophenyl ester 4-()lanth-4-denurinchlorohexyl)-2-fluorobenzoic acid-4-cyanophenyl ester Example 11 (Usage example) Trans'-4-propyl-(417anophenyl) ) Cyclohexane 24iJk% trans-4-pentyl-(4I-cyanophenyl)cyclohexane:
s6 [1% trans-4-hebutyl-(4'-cyanophenyl)cyclohexane 2531iS trans-
The liquid crystal composition A having the composition of 14-pentel-(4'-cyanobiphenyl)cyclohexane 15mf* has a nematic clearing point of 72°C, an electrostatic anisotropy value of +11°, and a viscosity at 20°C of 29 cp, Threshold voltage is 1.8
The 3V% saturation voltage was 2.53V.

The compound of the present invention, 4-(
The nematic clearing point of the liquid crystal composition to which 5 parts by weight of trans-4-hexylcyclohexyl)-2-benzoin #4-cyanophenyl ester is added is FuroCp, and the nematic clearing point is FuroCp.
The unidirectional value was 11. The viscosity at 20°C was 32 cp, the threshold voltage was 1.80V, and the saturation voltage was 2.50V. Moreover, it is possible to raise the N-1 point without changing the K threshold voltage or saturation voltage.

that's all

Claims (2)

[Claims] (1) 4-cyanophenyl 4-(trans-4-[substituted-cyclohexyl)-2-fluorobenzoate] represented by the general formula (in the above formula, R represents an alkyl group or an alkoxy group having 1 to 1 carbon atoms) Ester in form. (2) 4-(trans-4-fit m -cyclohexyl)-2-fluoro&'JiL4+! represented by the general formula (in the above formula, R represents an alkyl group or an alkoxy group having 1 to 1 carbon atoms). l*-4
- A liquid crystal composition containing at least one cyanophenyl ester derivative.