JPS59170055A - Chlorobenzoic acid ester - Google Patents

Abstract

NEW MATERIAL:A 2'-cyano-4'-halogenophenyl 2-chloro-4-alkoxybenzoate of formula I (R is 1-10C alkyl; X is F or Cl). USE:A liquid crystal composition having about -3 negative dielectric anisotropy, and usable for guest-host type display elements by mixing with another nematic liquid crystal and further for two frequency type display elements by combination with a liquid crystal having a positive dielectric anisotropy value. PREPARATION:A 2-chloro-4-alkoxybenzoic acid of formula II is reacted with SOCl2, etc. to give an acid chloride of formula III, which is then reacted with 2- cyano-4-chloro(or fluoro)phenol of formula IV in the presence of pyridine to afford the aimed compound of formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel liquid crystal compound having negative dielectric anisotropy,
Regarding liquid crystal compositions containing the same, liquid crystal display crystals utilize the optical anisotropy and dielectric anisotropy of liquid crystal substances, but depending on the display format, TN
It is divided into various types such as type (twisted nematic type), DS type (dynamic scattering type), guest-host type, and DAP type.
The properties of liquid crystal materials suitable for each use vary. However, it is common for all liquid crystal materials to be stable against moisture, air, heat, light, etc., and they are also required to exhibit a liquid crystal phase in as wide a temperature KiQ range as possible around room temperature. It is being However, at present, there is no substance that satisfies these conditions in the monochemical industry, and liquid crystal compositions obtained by mixing several types of liquid crystal compounds and non-liquid crystal compounds are not available.
The current situation is that

Recently, guest display, which is a color LCD display method, has been
Host-type liquid crystal display devices have started to attract attention. This uses a mixture of liquid crystal and dye, but liquid crystal with negative dielectric anisotropy is used for positive guest-host type display elements. Therefore, there is a need for liquid crystal compounds or liquid crystalline compounds having various properties, good compatibility, and negative dielectric anisotropy that can be used as constituent components of liquid crystals.

It is an object of the present invention to provide all standard liquid crystal compounds suitable for such uses.

That is, the present invention provides a 2-chloro-4-alkoxybenzene compound represented by the general formula (in the above formula, R represents an alkyl group having 1 to 10 carbon atoms, and X represents F or Ct). 1l
l-2'-77/-4'-halogenophenyl ester, and a liquid crystal composition containing at least one portion thereof.

The compound of the present invention itself does not exhibit liquid crystal a, but its dielectric anisotropy value is about 13, so by mixing it with other nematic liquid crystals, it can be used for guest-host type display devices. It is possible to obtain a liquid crystal composition having properties. Furthermore, by combining it with one having a positive dielectric anisotropy value, it can be used in a pulse frequency method type display element.

Next, the method for producing the compound of the present invention is shown. First, it is converted into an acid chloride using 2-chloro-4-alkoxyfermented total thionyl chloride, and then it is reacted with 2-cyano-4-chlorophenol in the presence of pyridine. In particular, the desired compound is obtained.

The chemical formula for this is 0 (in the above formula, R and .

The compounds of the present invention will be explained in more detail in the following examples.

Example 1 (Production of 2-chloro-4-pentyloxybenzoic acid-2'-cyano-47-chlorophenyl ester) (1) Production of 2-cya/-4-chlorophenol 5
- Chlorosalicylaldehyde oxime 20f in anhydrous vinegar [
Dissolve in 100WIJ and reflux for 10 hours. After the reaction, acetic anhydride is distilled off under reduced pressure. To the remaining oil, add 20 g of potassium hydroxide dissolved in 100 ml of water and 1 ml of ethanol.
Add 0.00 ml and heat at 80°C for 5 hours. When it is brought to room temperature and completely acidified with 6N hydrochloric acid, 2-cyano-4-
Crystals of chlorophenol precipitate. Filter this crystal,
Dry and use for the next reaction (accumulation: 14 g, 1 m, p, 1
64-168°CL.

(2) 2-cyano-4-chlorophenol obtained in esterification (1) 0
．． Dissolve 671 in 8 ml of pyridine, and add 1.00 f of 2-chloro-4-penaloxybenzene to this while shaking well. Add the acid chloride prepared above.

After the reaction, add 20 grams of toluene and pour into water. Separate the toluene layer, wash with 6N salt solution, 2N sodium hydroxide solution, and then water, and finally measure the anhydrous value. Dry with sodium chloride. When toluene is distilled off under reduced pressure, a crystalline substance remains, which is recrystallized from ethanol-2ethyl acetate to obtain the target product, 2-chloro-4-pentyloxybenzoic acid-2'-Schiff/-4'-chlorophenyl ester. is 0.919"4ut'Lfc.

Yield 58.5%. The melting point of this product is 95.7-96.1
It was °C.

Example 2 2-chloro-4 in Example 1 was prepared in the same manner as in Example 1.
- Using 2-chloro-4-propyloxybenzoic acid chloride instead of pentyloxybenzoic acid chloride, 2-
Chloro-4-propyloxybenzoic acid-2'-cyano-
4'-chlorophenyl ester was produced. The melting point of this product was 116.2-117.2°C.

Implementation fylJ 8 (Production of 2-chloro-4-pentyloxybenzoic acid-2'-cyano-4'-fluorophenyl ester) (1) Production of 2-cyano-4-fluorophenol 45 g of 5-fluorosalicylaldehyde oxime was Dissolve in 100ml of acetic anhydride and reflux for 10 hours.After the reaction, acetic anhydride is distilled off under reduced pressure.

The remaining oil was heated with a solution of 22 das of potassium hydroxide dissolved in 100 d of water and 100 ml of ethanol at 80°C for 5 hours. When the mixture is brought to room temperature and completely acidified with 6N hydrochloric acid, 2-cyano-4-fluorophenol crystals are precipitated. The crystals were filtered, dried, and then recrystallized with methanol, and the melting point was 120-122.
The yield at 1°C was 80f, which was used in the next reaction.

(2) Dissolve 0.501 of 2-cyano-4-fluorophenol obtained in esterification (1) in 81 VC of pyridine, and add 2-oo-4-pentyloxypropylene to the solution while shaking and mixing well. Add aromatic acid chloride made from 84y and thionyl chloride. After the reaction, add 20ml of toluene to the apparatus overnight.
Put the sword in the water. Toluene) fI is separated and 6N
Wash with salt, 2N sodium hydroxide solution, water, and finally dry with anhydrous sulfuric acid. When toluene is distilled off under reduced pressure, a crystalline substance remains, which is then diluted with ethanol.
Recrystallization from ethyl acetate yields the target product, 2-chloro-
0.56F of 4-pentyloxybenzoic acid-27-7/-4'-fluorophenyl ester was obtained, fc, yield 44.7%. The melting point of this product is 101.1-101.9
It was °C.

Example 4 [Usage example] Ester-based nematic liquid crystal composition LIXO
N) The N-I point of FN-45 (manufactured by Chinon (2), ) is 6
The viscosity of 8.4°C5Δε at -0, 9, and 20°C is 18.5 cp. To this mixture, 1% of commercially available Color Purple G-224ff manufactured by Merck & Co. was added and sealed in a cell to produce a guest-host cell.The threshold voltage was measured and found to be 8.80V.

Next, 10 ft of 2-chloro-4-pentyloxybenzoic acid-27-cyat-4'-chlorophenyl ester, which is a compound of the present invention! A liquid crystal composition containing 590 parts of FN-4 was prepared. The N-1 point is 34.5°C
1△ε is -1, 2, viscosity at 20゛C is 28.5c
When a guest-host type liquid crystal cell was prepared with 1% of the dye G-224 added thereto and the entire threshold voltage was measured, it was found to be 8.26V, which was a large drop.

341

Claims (2)

[Claims] (1) 2-chloro-4-alkoxybenzoic acid-2 represented by the general formula (in the above formula, R represents an alkyl group having 1 to 10 carbon atoms, and X represents F or Ct). '-Cyano-4'-halogenophenyl ester. (2) General formula (in the above formula, R is an alkyl group having 1 to 1 o carbon atoms,
A liquid crystal composition containing at least one 2-chloro-4-alkoxybenzoic acid-2'-cyano-4'-logenophenyl ester represented by (X represents F or Ct).