JPS6222778A - Nematic liquid crystal compound, liquid crystal composition and production of said compound - Google Patents

Abstract

NEW MATERIAL:A nematic liquid crystal compound expressed by formula I (R is 1-10C n-alkyl: X is H, CH3 or Cl). EXAMPLE:Hydroquinone ester of 1,4-bis-(5-n-butyl-2-thienylacrylic acid) expressed by formula II. USE:One component of liquid crystal compositions, which is a thiophene based nematic liquid crystal compound capable of exhibiting the liquid crystal phase within a wide temperature range under high temperature conditions and usable in a mixture with another nematic liquid crystal compound of nonnematic liquid crystal compound. PREPARATION:For example, a compound expressed by formula II and a compound expressed by formula III are subjected to dehydration reaction in the presence of pyridine in a solvent, e.g. dichloroethane, using a dehydrating agent, e.g. N,N'-dicyclohexylcarbodiimide, etc., to afford the aimed compound expressed by formula I in one stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a novel thiophene-based nematic 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.

[Technical Background of the Invention] Liquid crystals have the property of changing their orientation under the influence of electric or magnetic fields, significantly changing optical properties such as light scattering and birefringence, 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 chemical stability.

[Objects of the Invention] An object of the present invention is to provide a novel thiophene-based nematic liquid crystal compound having a wide liquid crystal temperature range at high temperatures, a liquid crystal composition containing this compound, and a method for producing the compound.

[Structure of the Invention] That is, the nematic liquid crystal compound of the present invention has the general formula (wherein, R is a linear alkyl group having 1 to 10 carbon atoms,
is a hydrogen atom, a methyl group, or a chlorine atom).

Compounds included in the present invention include 1,4-his-(5-alkyl-2-
chenyl acrylic M) hydroquinone ester, 1,4-his=(5-alkyl-2-chenyl acrylic acid)-, represented by (in the formula, R represents a linear alkyl group having 1 to 10 carbon atoms) 2-Methyl-hydroquinone ester, 1,4-his-(5-n-alkyl-2-
(chenyl acrylic acid)-2-chloro-hydroquinone ester.

In addition, these manufacturing methods include (1) a compound represented by the general formula (in the formula, R represents a straight alkyl group having 1 to 10 carbon atoms) and a compound represented by the general formula (in the formula, x i + hydrogen atom, methyl group, or (representing a chlorine atom) in the presence of a dehydrating agent to produce a compound represented by the general formula (in which R and X have the same meanings as above); or

(2) A compound represented by the general formula (in the formula, R1jrA represents a straight alkyl group having 1 to 10 atoms) is reacted with a chlorinating agent to form the general formula (in the formula, R has the same meaning as above) An acid chloride represented by the general formula % (1) (wherein X represents a hydrogen atom, a methyl group, or a chlorine atom)
There is a method of obtaining a compound represented by the general formula (wherein R and X have the same meanings as above) by reacting with a compound represented by the above formula.

Further, the liquid crystal composition of the present invention is characterized in that it contains one or more compounds represented by the general formula (I).

Next, the manufacturing method of the present invention (6) is explained.

! l! In the production method (1), examples of the dehydrating agent include N-hydroxyphthalimide, N,N'-disuccinimidyl carbonate, N,N'-dicyclohexylcarbodiimide, etc., and in particular N.

N'-dicyclohexylcarbosiimide N. pravd
The method of i c' et al. (J. Chem.

Soc. , 4633. , 1964) is preferred. Also N
, N'-dicyclohexylcarbodiimide compound (V
) in a solvent such as dichloromethane, dichloroethane, or carbon tetrachloride in the presence of pyridine to obtain the desired compound in one step. The chlorinating agent used in production method (2) includes thionyl chloride, phosphorus trichloride, phosphorus pentachloride, etc., but thionyl chloride is particularly preferred from the viewpoint of ease of treatment after the reaction. When thionyl chloride is used, the molar excess of 5-n-alkyl-2-chepyrylacrylic acid of formula (V) is centrifuged, and after the reaction, thioyl chloride is distilled off under reduced pressure. Just leave. 5-n- of formula (W)
Alkyl-2-chenyl acrylic acid chloride and formula (v
The reaction l) with the hydroquinone derivative is carried out in an inert solvent such as ethyl ether, benzene, ethyl acetate, etc.
In particular, ethyl acetate is preferred from the viewpoint of solubility. In addition, in order to remove hydrogen chloride generated during the reaction, pyridine,
It is preferable to add a basic substance such as triethylamine. The product after the reaction can be subjected to treatments such as organic solvent extraction, water washing, and crystallization to yield 1 q of the target compound.

5-n-alkyl-2-chenyl acrylic acid used as a raw material in the present invention is produced by the method for which the present inventors previously applied for a patent (Japanese Patent Application No. 59-267133, Japanese Patent Application No. 59-2671).
No. 3, Japanese Patent Application No. 133 (Sho 60-55).

1st stage ↓, 3rd stage ↓ 4th stage ↓ (wherein, R is a linear alkyl group having 1 to 10 carbon atoms, R
1 represents a straight chain alkyl group having one less carbon atom than R; ) In the first step, thiophene is reacted with n-alkylcarboxylic acid or an acid chloride or acid anhydride of n-alkylcarboxylic acid to produce n-alkyl-2-chenylketone of formula (a).

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 in ethyl ether as a solvent and then with N,N-dimethylformamide or 2-n-alkylthiophene is reacted with phosphorus oxychloride as a catalyst. , N,N-dimethylformamide to form 5-n-alkyl-2-thiophene aldehyde of formula (C) IN! will be built.

In the fourth step, methyl 5-n-alkyl-2-chenyl acrylate obtained by refluxing 5-n-alkyl-2-thiophenaldehyde and methyl acetate in the presence of sodium is subjected to alkaline hydrolysis, or Using pyridine containing a small amount of piperidine as a solvent, 5-n-alkyl-2-
Thiophene aldehyde and malonic acid are reacted to form the formula (V
) of 5-n-alkyl-2-chenyl acrylic acid)
be notified.

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

R-Q-C-0-○-R' [wherein R and R' are each "III H2It 4
1-1n-CmH2m +l-0-1n-c, H2m
++-C-0-1-CN 1-NO2 (where m is an integer of 1 to 10) 1 R-Q-co=N-○-R' [In the formula, R and R' are each n-C, 82m ++-
1n-CmH2Ill 4l-0-1n-c, H2I
ll represents either +1-C-0-1-CN or -NO2 (where m is an integer of 1 to 10)] R-CI>-〇-R・[In the formula, R and R' each represent n- CmH2tn ++
-1゜n-cTn■2 vn ++-0-1n-C11H2m
+1-C-0-1-CN, -NO2 (where m is an integer of 1 to 10)] η R-Q-c-s-〇-R' [In the formula, R and R' are n-C, IIH2Tn+, respectively
B,n-cIIIH2Ill 4l-0-1n-c,l
lH2Ill 4l-C-0-1-CN, -NO
2 (however, m is an integer from 1 to 10)] R-<E>-〇-R・[In the formula, R represents n-c, H2m ++-, and R' represents -CN, - Represents either NO2 (however, m
is an integer from 1 to 10)] R-■-c-o-〇-R' [In the formula, R is n-C, H2II +1-, R'
Han-C1IIH2tn ++-1n-C, IIH2m
+t-0-1n-CmH2□1-0-j-0-, -C
Represents either N or -NO2 (where m is 1
~10 integer)] R-<E>-C-8-〇-R' [In the formula, R represents n-C, H2m ++-, and R'han
-C, IIH2m ++-1n-ClnH2m +t-
0-1n-C,, lH2m +I -0-a-0-, -
Represents either CN or -N02 (where m is 1 to 1
an integer of 0)]]R−○−○−○−R [In the formula, R and R′ are respectively n−c and mH2rn +
+-1n- et al ■211 橿ji〇-・.

nc, H2II ++-0-C-0-1-CH, -
802 (however, m is an integer from 1 to 10)] R-■-〇-○-R・[In the formula, R represents n-C, H2Ill +1-, R'
Han n-CWIH2m +1”, n-C, II 211I
n-0-1n-C, IIH2, , 1-0-C-0-,
-CN, -NO2 (however, m
is an integer from 1 to 10)]R-<EE>-■-C-0-O
-R' [wherein R represents n-Cl1H2m ++-,
R' is n-C, IIH21+1 ++-1n-cWII
f 2 Wl++-0-1n-CwlH2,,1-0-
Represents any of C-0-, -CN, -NO2 (where m is an integer of 1 to 10)] [wherein R is n-C, H
2Ill u-, X represents either F1Cβ or Br (where m is an integer of 1 to 10)] [In the formula, R represents n-CIIIH2u++-, X represents either F1Cβ or Br (However, ■ is 1 to 1
0 integer)] In the E formula, R represents n-CTnN 2 K +1-, and
HaF.

Represents either CJ2 or Br (however, m is 1 to 10
[In the formula, R represents n-CvIIH2m +1-,
Integer of 0)] [In the formula, R and R' are n-C11lH2m n-1n-
c, ti 2 m ++-0-, X is 10N
or -Br (where m is an integer from 1 to 10)]
Next, Table 1 shows the physical properties of the main liquid crystal compounds of the present invention.

(Space below) Table 1 (In the table, phase transition temperature C is a crystalline phase, N is a nematic liquid crystal phase, 11 isotropic liquid phase, arrow (J phase transition is shown in Table 1) [Examples of the invention] Next, the present invention will be specifically explained with reference to Examples and formulation examples.

Example 1 5-propyl-2-chenyl acrylic IU 2.0 g (0
, 01 mol) was dissolved in 3 m 12 i,' of thionyl chloride and refluxed for 30 minutes. Thereafter, excess thionyl chloride was distilled off under reduced pressure. Next, the obtained reaction product was cooled and dissolved in 30 yyl of ethyl ether.

This solution was added dropwise to a mixture of 10 mJ of pyridine and 50 mβ of ethyl acetate containing 0.55 g (0,005 mol) of hydroquinone, and then left overnight at room 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 following compound was obtained by crystallization from ethanol. Yield 64.4%.

NMR (δ, CDC1a) 1, QO (t, 6H= -CH3) 1.73 (m, 4H, -CH2-) 2.81 (t, 4H, -CH2-) 6.29 (d, 2H, Hd ) 6.77 (6,2H,Hb) 7.14 (d, 2H, Ha) 7.18 (s, 41-1.He) 7.88 (d, 2H, HC) Examples 2-3 Examples The compounds listed in Table 2 were obtained in the same manner as in Example 1, except that 0.005 mol of the following compound was used instead of 0.005 mol of hydroquinone in Example 1.

1”22- Example 4 5-Methyl-2-chenyl acrylic 112.19 (0,
0.55 g of hydroquinone was added to the solution (01 mol), and further 5 TrLβ of pyridine and 60 mR of dichloroethane were added and dissolved. After adding N,N'-dicyclohexylcarbodiimide and stirring, the mixture was allowed to stand at room temperature for 24 hours. The generated urea body was removed, and the solvent of the filtrate was distilled off under reduced pressure. Ethanol was then added to dissolve the mixture under heating, and the mixture was cooled to crystallize. The obtained crystals were filtered and recrystallized from ethanol to obtain 1.2 g of the following compound.

Yield 58.5%.

NMR (δ.CDCβ3) 2,53 (s,6H,-CH3) 6,28 (d,2H,Hd) 6,74 (d,2H,l-(b) 7,12 (d,2H,Ha) 7, 18 (s, 4t-1, t-1e) 7, 86 (d
, 2H, Hc) Examples 5 to 10 5-Methyl-2-chenyl acrylic 1 in Example 4
In place of 0.01 mol, the following compound O.

The compounds listed in Table 3 were obtained in the same manner as in the same Example except that 01 mol was used.

C2 +15-Q-CH-CH-COO11n- C4
119+Cil=CH-CDDlln-C,,
Old 1-Q- CIl=CIl-COOHn- C6
11,3i9CH=CH-COONn-C7 old s
-Q- cu-cu-coon 28 - Example 11 2.3 g of 5-butyl-2-chenyl acrylic acid (0,0
1 mol) of methylhydroquinone (0.62 g (0.00
5 mol) was added thereto, and 5 TrLJ2 of pyridine and 60 mβ of dichloromethane were added to a colander and dissolved. N,N'-dicyclohexylcarbodiimide 2.1 (0.01 mol)
After stirring, the mixture was left standing at room temperature for 24 hours. The generated urea body was filtered off, and the solvent of the filtrate was distilled off under reduced pressure. Ethanol was then added and dissolved by heating, followed by cooling and crystallization.

The crystals were separated by filtration and recrystallized from ethanol to obtain 1.6 g of the following compound. Yield 63%.

NMR (δ, CDC, e) 0.95 (t, 6H, -CH3) 1.53 (m, 8H, -CH2-) 2.21 (S, 3 days, -CH3) 2.84 (↑, 4H , -CH2-) 6.28 (d, IH, Hd) 6, 32 (d, IH, To1d')6.
76 (d, 2H, Hb and Hb') 7.05 (d
, 3H, f-fe, Hf and ]”g) 7.14 (d
, 21-1.8a and Ha') 7.87 (d, I
H, l-1c) 7.90 (d, IH, Hc') Examples 12 to 13 In place of 0.01 mol of 5-butyl-2-chenyl acrylic acid in Example 11, 0.01 mol of the following compound The compounds listed in Table 4 were obtained in the same manner as in the same Example except that moles were used.

n-c5 old 11> ch=c■-coo[+-32
Example 14 0.72 g (0,005 mol) of chlorohydroquinone was added to 2.3 g (0,001 mol) of 5-butyl-chenyl acrylic acid, and then 5771°1 of pyridine and 60 m, g of dichloroethane were added and dissolved. did.

N,N'-dicyclohexylcarbodiimide 19
(0.01 mol) was added, stirred, and allowed to stand at room temperature for 24 hours. The generated urea body was filtered off, and the filtrate was concentrated under reduced pressure.

Add ethanol and dissolve by heating, and after cooling, filter the crystals.
Recrystallization from ethanol gave 1.8 g of the following compound. Yield 68.1%.

NMR (δ. CDC 3) 0, 95 (t, 6H, -CH3) 1, 53 (m, 8t-(, -CH2 -) 2,
84 (↑,4H,-CM2-) 6,26 (d.1t-1.Hd) 6,32 (d,11-(,Hd')6,77 (
d, 21-1, Hb and Hb'>7, 16 (m,
4H. Ha. Ha', He and Ha) 7,31 (q,1H,Hf) 7,87 (d,1t-1.t-1c)7,93 (d
. The compounds listed in Table 5 were obtained.

n-C5 old+Qct+=cu-coonn-c6
Old Ben CH=CI-1-COONn- C7 ■1s
QCH=CH-COOtl-36 - Example 1B (formulation example) The following liquid crystal composition (A> shows a liquid crystal phase up to 74°C (N-+I).The crystallization temperature (N-C) is 0°C or lower. It is.

n-C3H7-■-coo-Q-cN 30% (weight) n-C5tl 11-■-coo-〇-CN40% (weight) n-C's If + +-■-coo-Q-QC5H
,.

30% (weight) When 10% (weight) of the following compound obtained in the present invention was added to 90% (weight) of this composition (A), the results shown in Table 6 were obtained.

(N in the table is a nematic liquid crystal phase, ■ is an isotropic liquid phase, C
indicates a crystalline phase. )

Claims (7)

[Claims] (1) Represented by a general formula ▲ Numerical formulas, chemical formulas, tables, etc. A nematic liquid crystal compound characterized by (2) The nematic liquid crystal compound according to claim 1, wherein X is a hydrogen atom. (3) The nematic liquid crystal compound according to claim 1, wherein X is a methyl group. (4) The nematic liquid crystal compound according to claim 1, wherein X is a chlorine atom. (5) Compounds represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R is a straight-chain alkyl group having 1 to 10 carbon atoms, and X is a hydrogen atom, methyl group, or chlorine atom) A liquid crystal composition characterized by containing one or more types of. (6) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents a straight chain alkyl group having 1 to 10 carbon atoms) and the general formula ▲ Numerical formulas, chemical formulas, tables, etc. Yes▼ (In the formula, X represents a hydrogen atom, methyl group, or chlorine atom)
To obtain a compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (in the formula, R and X have the same meanings as above) by reacting the compound represented by A method for producing a nematic liquid crystal compound characterized by: (7) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents a straight-chain alkyl group having 1 to 10 carbon atoms) A compound represented by the general formula ▲ is reacted with a chlorinating agent. There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R indicates the same meaning as above) Acid chloride, and then there are general formulas ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, X is a hydrogen atom) , indicating a methyl group or a chlorine atom)
A nematic liquid crystal compound characterized by reacting with a compound represented by the following to obtain a compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (wherein R and X have the same meanings as above) manufacturing method.