JPS62273974A - Biphenyl ester based liquid crystal compound of thienylcarboxylic acid and thiophenecarboxylic acid, liquid crystal composition and production thereof - Google Patents

Abstract

NEW MATERIAL:A liquid crystal compound expressed by formula I (R is 2-14C straight-chain alkyl; n is 1 or 0; X is cyano or Br). EXAMPLE:4'-Cyano-4-biphenylyl 5-n-propyl-2-thienylacrylate and 4'-cyano-4- biphenylyl 5-n-propyl-2-thiophenecarboxylate. USE:A liquid crystal composition having a wide liquid crystal temperature range. PREPARATION:For example, a compound expressed by formula II is reacted with a compound expressed by formula III in the presence of a dehydrating agent to afford the aimed compound expressed by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to liquid crystal compounds used as electrical display materials. More specifically, the present invention relates to a novel thiophene-based liquid crystal compound exhibiting a liquid crystal phase over a wide temperature range, a liquid crystal composition containing this compound, and a method for producing the liquid crystal compound.

(Prior Art) Liquid crystals have the property of changing their orientation under the influence of electric or magnetic fields, thereby significantly changing their optical properties, and are widely used in electrical display devices. Properties required of the liquid crystal used in such display devices include a wide liquid crystal temperature range, low viscosity, high dielectric anisotropy, and optical stability.

Conventionally, liquid crystal compounds having three benzene rings bonded have been known, but liquid crystal compounds containing a thiophene ring and having a wide temperature range have not been known. In addition, conventional liquid crystal materials with three benzene rings bonded have a high temperature at which they change from a liquid crystal phase to a crystal, so when added to a liquid crystal composition, they have the disadvantage that only a few percent can be added because it increases the crystallization temperature.

(Problems to be Solved by the Invention) Among liquid crystal compounds having two or more rings, the azomedine type compounds, which have been relatively widely used in practice, have a low transition temperature and are optically stable. It easily hydrolyzes in the presence of even the slightest amount of water and loses its liquid crystallinity. On the other hand, the ester type has a relatively high transition temperature, but is moisture and optically stable. In view of the above circumstances, we created an ester-type compound with a dielectric anisotropy that is larger in the long axis direction of the molecule by bonding a highly polar cyano group or halogen atom as the terminal group and bonding a sulfur-containing thiophene ring to the other end group. As a result of various studies on colorless liquid crystal compounds with a wide temperature range, we discovered that a series of new compounds containing a thiophene ring exhibit liquid crystallinity.

That is, the object of the present invention is to provide a new phenyl ester liquid crystal compound of chenyl acrylic acid and thiophenecarboxylic acid having a wide liquid crystal temperature range, a liquid crystal composition containing this compound, and a method for producing the same.

[Structure of the invention]

(Means for Solving the Problems) That is, the liquid crystal compound of the present invention has the general formula (wherein R is a linear alkyl group having 2 to 14 carbon atoms, n is 1 or O, and X is a cyano group or bromine atom). Compounds included in the present invention include 5-n represented by the general formula (wherein R is a straight-chain alkyl group having 2 to 14 carbon atoms, and X is a cyano group or a bromine atom) when n is 1. -Alkyl-2-chenylacrylate-4'-substituted-4-biphenylyl and the general formula when n is 0 (wherein R is a straight-chain alkyl group having 2 to 14 carbon atoms, X is a cyano group or 5-n-alkyl-monosubstituted-4-biphenylyl represented by the general formula (II>
5-n-alkyl-2-chenylacrylic acid-47-dia2-4-biphenylyl represented by the general formula (in the formula, R represents a straight-chain alkyl group having 2 to 14 carbon atoms) as a compound included in 5-n-alkyl-2-chenylacrylate-4-bromo-4-biphenylyl represented by the general formula (wherein R represents a straight-chain alkyl group having 2 to 14 carbon atoms), and As a compound included in the general formula (III), 5-looalkyl-2-thiophenecarboxylic acid represented by the general formula (in the formula, R represents a straight-chain alkyl group having 2 to 14 carbon atoms) @4''-cyano- 4-biphenylyl and 5-n-alkyl-2-thiophenecarbon M 4''-70 mo-4-biphenylyl represented by the general formula (in the formula, R represents a straight-chain alkyl group having 2 to 14 carbon atoms) can give.

These liquid crystal compounds can be obtained by Manufacturing Method 1 and Manufacturing Method 2 described below.

Production method 1 A compound represented by the general formula (wherein R is a linear alkyl group having 2 to 14 carbon atoms, n is 1 or O) and the general formula %formula%() (in the formula represents a cyano group or a bromine atom) in the presence of a dehydrating agent to produce a compound represented by the general formula (wherein R, n and X have the same meanings as above) can do.

In this method, N-hydroxyphthalimide, N,N'-disuccinimidyl carbonate,
Examples include N,N'-dicyclohexylcarbodiimide, and in particular, the method of N, Pravdic et al. (J. Che.
m, Soc, 4633, 1964) is preferred.

In addition, N,N'-dicyclohexylcarbodiimide can be prepared in one step by using an equimolar amount of the compound of formula (■) and dehydrating it in a solvent such as dichloromethane, dichloroethane, or carbon tetrachloride in the presence of pyridine. The desired compound can be produced.

Production method 2 A compound represented by the general formula (in the formula, R is a linear alkyl group having 2 to 14 carbon atoms, and n represents 1 or O) is reacted with a chlorinating agent to produce a compound represented by the general formula (formula (in which R and n have the same meanings as above), and then a compound represented by the general formula % (in which X represents a cyano group or a bromine atom) as an inert compound. A compound represented by the general formula (wherein R, n and X have the same meanings as above) can be obtained by reacting in a solvent.

The compound represented by can be (q).

Examples of the chlorinating agent used in this method include thionyl chloride, phosphorus trichloride, and phosphorus pentachloride, but thionyl chloride is particularly preferred from the viewpoint of ease of treatment after the reaction.

When thionyl chloride is used, it may be refluxed using an excess molar amount relative to the compound of formula (■), and the reacted double thionyl chloride may be distilled off under reduced pressure. Acid chloride of formula (X) and formula (I
The reaction of X) with 4-hydroxy-4'-substituted biphenyl is carried out in a solvent such as ethyl ether, benzene, or ethyl acetate, with ethyl acetate being particularly preferred from the viewpoint of solubility.

Further, in order to remove hydrogen chloride generated during the reaction from the system, it is preferable to add a basic substance such as pyridine or triethylamine. The product after the reaction can be subjected to treatments such as organic solvent extraction, water washing, and crystallization to obtain the desired compound.

5-n-Furkyl-2-chenyl acrylic acid and 5-n-alkyl-2-thiophenecarboxylic acid used as raw materials in the present invention are obtained by a method previously applied by the present inventors (
Japanese Patent Application No. 59-267133, Japanese Patent Application No. 59-26713
No. 4, Patent Application No. 1983-55433, Patent Application No. 1983-260
No. 935).

(Left below) 2nd stage ↓ CH2-R+ (b) 3rd stage ↓ RQCHO (C) 4th stage ↓ RQcu = CH-B-on ・< v ma) (In the formula, R is the number of carbon atoms from 2 to 14 straight chain alkyl group, R1 is R
In the first step, thiophene is reacted with an n-alkylcarboxylic acid or an acid chloride or acid anhydride of an n-alkylcarboxylic acid to form the formula (a). ) n-alkyl-2-thenyl ketone is produced.

In the second step, 2-n-alkylthiophene of formula (b) is produced by reducing n-alkyl-2-thenylketone with hydrazine hydrate in the presence of an ethylene glycol solvent.

In the third step, 2-n-alkylthiophene is reacted with phenyllithium using ethyl ether as a solvent, and then with N,N-dimethylformamide, or with 2-n-alkylthiophene using phosphorus oxychloride as a catalyst. By reacting with N,N-dimethylformamide,
5-n-alkyl-2-thiophene aldehyde of formula (C) is prepared.

In the fourth step, 5-n-alkyl-
Refluxing 2-thiophenaldehyde and methyl acetate to form 19
5-n-Alkyl-2-methyl acrylate is hydrolyzed with alkali or pyridine containing a small amount of piperidine is used as a solvent to give 5-n-alkyl-2-
By reacting thiophene aldehyde and malonic acid, the formula (■
5-n-alkyl-2-chenyl acrylic acid of a) is produced.

Also, 5-n-alkyl- can be manufactured by the following steps.

In the formula, R represents a straight chain alkyl group having 2 to 14 carbon atoms)
It can be produced by oxidizing 5-0-furkyl-2-thiophene aldehyde with silver oxide, sodium hypochlorite, potassium hypochlorite, sodium hypobromite, potassium hypobromite, or the like.

4-hydroxy-4'- which is the other raw material of the present invention
Bromobiphenyl is a commercially available product. 4-hydroxy-4
'-Cyanobiphenyl can be produced by the following steps.

↓ ) 10-@- [phase] CM It can be produced by reacting 4-hydroxy-4'-bromobiphenyl with cuprous cyanide in N,N-dimethylformamide.

Examples of other nematic liquid crystal compounds and non-nematic liquid crystal compounds that can be mixed with the liquid crystal compound of formula (I>) include the following compounds.

R@-C-0*).

[In the formula, RI3 and R' are each n-Cm)lzm+
+ -1n-CmHzm++-0-1n-Cm) Izu
-C-0-, -CN, -NO2 (
However, m is an integer from 1 to 10)]R◎CH=N◎R.

[In the formula, R and R' are each n-CmHzm++
-1n-C5Hz++-0-, n-CmHzm++-C
Represents either -0-1-CN or -NO2 (where m is an integer from 1 to 10)]R(K-protection R.

[In the formula, R and R' are each n-CmHzTSukude-1n
-CmHz11+1-0-, n-CmHzm++-C
-0-, -CM, -NO2 (where m is an integer from 1 to 10)]n-CmHzm++-0-,
n-Cmf(zm -C-0-1-CN, -NO2
(m is an integer from 1 to 10)] R name 4 R' (In the formula, Rl represents tn-CmHzm++-, R' is n
-Cm)Izm++ -1n-CmHzm++-0-,
n-CmHzm++-C-0-1-CN, -NO2
Table V (where m is an integer from 1 to 10)]R(
Cold-0■R゛ [in the formula Rhan-Cm)]zz++-, R'han-CmHzm++ -1゜n-C5Hz++-0-C-0-, -CN, -N
Represents either O2 (m is an integer from 1 to 10)] R' is n-CmHzm++-0-, n-CmHzm++
-C-1-NO2 (where m is 1 to 1
0 integer)] R (integer IR' [where R and R' are each low CmHzm++-1
゜n-C11182N-0-C-0-, -CN, -N
Represents either O2 (where m is an integer from 1 to 10)] R gutter
-C5Hz++-1O n-CmHzllH, l-0-C-0-, -CN,
-NO20) If L Kawo (however, m is 1 to 10)
)] [In the formula, R represents nn-C1Hz++-, and R' represents n-C
m H211)+I.

n-CmHzm++-0-C-0-, -CN, -
NO2 (represents DiftL Kawo (where m is an integer from 1 to 10)] [In the formula, R represents +1-C1Hz+1-, X represents F,
Represents either CJ2 or Br (where m is an integer of 1 to 10) [wherein R represents n-CmHzm-, X represents F1
CJ2.8" (where m is an integer from 1 to 10)] [In the formula, R represents n-CmHzm++-, and X represents either F1CJ?, 8r (however, m is 1 to 1
an integer of 0)] [wherein R represents n-CmHzm-,)N
, tF, or CJ2.8r (where m is 1
~10 integer)] [wherein R and R' are n-Cm)lz
l)+I-1nl-1n-C++-0-, X is -
Represents CN or -Br (where m is an integer from 1 to 10)
] (Function) The physical properties of the main liquid crystal compounds of the present invention are shown in Tables 1 and 2.

(Left below) 1st table (C in the phase transition temperature (0) in the table indicates a crystalline phase, N indicates a nematic liquid crystal phase, S indicates a smectic liquid crystal phase, ■ indicates an isotropic liquid phase, and arrows indicate a phase transition. (Example) Next, the present invention will be specifically explained with examples of raw material production, examples, and formulation examples. .

Raw material production example 1 4-hydroxy-4'-bromobiphenyl 12.45 CI (0,
0.05 mol) and 5.4 CJ (0.06 mol) of cuprous cyanide were added, and the mixture was stirred and refluxed for 5 hours. After the reaction, it was cooled to 70°C.

Separately, 22 g (0.08 mol) of ferric chloride hexahydrate was added to 9 mj1. The solution was dissolved in an aqueous solution of 35m and e containing 35m, and added dropwise to the above reaction solution. After stirring at 60 to 70°C for 30 minutes, 300 mft of ethyl acetate and 100 mft of water were added, and the mixture was cooled with stirring. Separate the ethyl acetate layer and reduce the aqueous layer to 150 ml.
mβ was extracted with ethyl acetate, combined with the previous extract, and treated with dilute hydrochloric acid and water in that order. After distilling off ethyl acetate, the residue was dissolved in methanol, treated with activated carbon, and crystallized by adding water to obtain 3.9q of 4-hydroxy-4'-cyanobiphenyl. Yield 39%.

Example 1 5-propyl-2-chenyl acrylic lfi 0.98
1 (0,005 mol) and 4-hydroxy-4'-bromobifu(di) Lt 1.25 Q (0,()05-
dichloromethane containing 5 mfl of pyridine and 60 mfl of pyridine.
Dissolved in mβ. Next, N,N'-dicyclohexylcarbodiimide Cl (0.005 mol) was added, stirred, and allowed to stand overnight.

The generated urea body was filtered off, and the solvent of the filtrate was distilled off.

The crystals obtained by adding ethanol to crystallization were recrystallized from ethanol to obtain the following compound 1.52 CI.

Yield 71.2% NMR (δ.CDCβ3) 1,00(t,3H, - CH3 >1,74(m,
2H, -CH2-)2,81(t,2M.,
-CH2 - ) 6, 31 (d, 1M, Hd) 6, 77 (d, IH, )Ib) 7, 15 (d, IH, Ha) 7, 24 (d, 2H, He) 7, 45 (d , 2M, Hh) 7, 54 (d, 4H. Hf and HCI>7,
90 (d, 1N, , HC) Examples 2 to 8 The following compound o. The compounds listed in Table 3 were obtained in the same manner as in the same Example except that oos mol was used.

Table 3 Example 9 5-propyl-2-chenyl acrylic 710.98 C
l (0,005 mol) and 4-hydroxy-4'-cyanobiphenyl 0.98 CJ (0,
005 mol) was dissolved in 60 mfl of dichloromethane containing 5 mλ of pyridine. Next, 1.04 g (0,005 mol) of N,N'-dicyclohexylcarbodiimide was added, stirred, and allowed to stand overnight. The generated urea body was filtered off, and the solvent of the filtrate was distilled off. The crystals obtained by adding ethanol were recrystallized from ethanol to obtain the following compound 1.
．． 40 CI was obtained. Yield 75.1%.

NMR (δ, CDCJ23> 1.00 (t, 3H, -CH3) 1.74 (m, 2H, -CH2-) 2.82 (t, 3M, -CH2-) 6.31 (d,
IN, Hd) 6.78 (d, IH, Hb) 7, 16 (d, IH, Ha) 7, 28 (d, 2H, He) 7.66 (d, 6H, Hf, HQ and Rh) 7.
91 (d, IH, Hc) Examples 10 to 13 The fourth example was prepared in the same manner as in Example 9 except that 0.005 mol of the following compound was used in place of 5-propyl-2-chenyl acrylic acid. The compounds listed in the table were obtained.

(Leaving space below) Table 4 Examples 14 to 21 Same as Example 1 except that 0.005 mol of the following compound was used instead of 0.005 mol of 5-propyl-2-chenyl acrylic lO. The compounds listed in Table 5 were obtained.

Examples 22 to 26 0.005 mol of the following compound was substituted for 0.005 mol of 5-propyl-2-chenyl acrylic IIQ in Example 9.
The compounds listed in Table 6 were obtained in the same manner as in the same Example except that moles were used.

(Margin below) Table 6 Example 27 5-ethyl-2-chenyl acrylic l O,91C1 (
0,005 mol) was dissolved by adding 2 mβ of dichloromethane and 2 mi of dichloroethane, and 4 ml of thionyl chloride was added thereto, followed by continuous flow for 1 hour. Thereafter, the solvent and excess thionyl chloride were distilled off under reduced pressure. The obtained reaction product was cooled and 30 mβ of ethyl ether was added.

Add 1.25% of this solution to 4-hydroxy-bromodophenyl
The mixture was added dropwise to a mixed solution of 10 m of pyridine (0,005 mol) and 70 mβ of ethyl acetate, and then allowed to stand overnight at air temperature. This reaction solution was treated with dilute hydrochloric acid, water, dilute caustic soda, and water in this order. After distilling off ethyl acetate, the residue was recrystallized from ethanol to obtain the following compound 1.40. Yield: 67.
8%.

NMR (δCDCβ3) 1.34 (i, 3N, -Cth) 2.88
(Q, 21.-CH2-)6.31 (d, 1M
, Hd ) 6.78 (d, IH, Hb ) 7.15 (d, IN , Ha ) 7.24 (d, 2H, He) 7.45 (d, 2H, song) 7.54 (d, 4H , Hf and Hg) 7.90 (
d, IN, Hc) Example 28 Same as Example 27 except that 5-ethyl-2-thiophene carbonyl y2o, oos mol was used instead of 5-ethyl-2-chenyl acrylic 1o, oos mol. In the same manner, the following compound 1.020 was obtained. Yield 52
,7%.

NMR (δ, CDC, e3) 1.37 (t, 3H, -CH3) 2.93 (Q, 2M, -CH2-) 6.88 (d
,1)1. ) lb) 7.28 (d, IH, HC) 7.45 (d, 2H, Hf) 7.55 (d, 4H, Hd and He) 7.83 (
'd, IH, Ha) Example 29 (formulation example) The following liquid crystal composition (A) shows a liquid crystal phase up to 72.5°C (N-1), and the crystallization temperature (N→C) is 0°C or lower. It is.

Composition (A) n-c 5 H+ + -@-@@-CN 10%
When 5% (weight) of the following compound obtained in the present invention was added to this composition (A>95% (weight)), the results shown in Table 7 were obtained.

(2) CsH++i>COO-oo-cN (blank below) phase, C indicates a crystalline phase, and arrows indicate phase transitions. ) [Effects of the Invention] As described above, it was possible to obtain a novel thiophene-based liquid crystal compound having a wide liquid crystal temperature range and a liquid crystal composition containing this compound.

Claims (8)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R is a straight chain alkyl group having 2 to 14 carbon atoms, n is 1 or 0, and X is a cyano group or a bromine atom. ) A liquid crystal compound characterized by being represented by: (2) Claims represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. The liquid crystal compound according to item 1. (3) Claims expressed by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. The liquid crystal compound according to item 1. (4) The liquid crystal compound according to claim 1, wherein X is a cyano group. (5) The liquid crystal compound according to claim 1, wherein X is a bromine atom. (6) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc.
A liquid crystal composition comprising at least one species. (7) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. Formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, X indicates a cyano group or a bromine atom)
In the presence of a dehydrating agent, a compound represented by the general formula ▲ has a mathematical formula, a chemical formula, a table, etc. ▼ (in the formula, R, n and X have the same meanings as above). A method for producing a liquid crystal compound, characterized in that: (8) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. It is reacted with a curing agent to form a trichloride represented by the general formula ▲ Numerical formula, chemical formula, table, etc. (in the formula R and n have the same meanings as above), and then the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, X represents a cyano group or a bromine atom.) By reacting with a compound represented by A method for producing a liquid crystal compound, characterized by obtaining a compound represented by (indicating a meaning).