JPS61277658A - Halogeno aromatic compound - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I (R ius 1-10C alkyl; Z is F, Cl or Br; l and m are 0 or positive numbers to give 1 or 2 total of l+m). EXAMPLE:trans-4-Propyl-(3-cyano-4-fluorophenyl)cylohexane. USE:A liquid crystal composition having great positive dielectric anisotropy and good compatibility with another liquid crystal substance. PREPARATION:A 4-substituted acetanilide expressed by formula II is reacted with bromine in acetic acid solvent to give a bromo-substituted derivative expressed by formula III, which is then aminated and diazotized to afford a diazonium tetrafluoroborate. The resultant diazonium tetrafluoroborate is then thermally decomposed to give a fluorobromo-substitution product expressed by formula IV, which is further reacted with cuprous cyanide in a basic solvent, e.g. N,N-dimethylformamide, to afford the aimed compound expressed by formula I (Z is F).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel logeno aromatic compound and a liquid crystal composition containing this halogeno aromatic compound.

[Prior art]

Display elements using liquid crystal materials utilize the optical anisotropy or dielectric anisotropy of liquid crystal materials, and there are various display methods such as reed, twisted nematic, dynamic scattering, guest host, and DAP types. . The properties required of the liquid crystal materials used in these display elements differ depending on the display method, but they must exhibit a liquid crystal phase over as wide a temperature range as possible and be stable against moisture, heat, light, air, etc. Commonly requested. At present, there is no single compound that satisfies all such requirements, and liquid crystal compositions obtained by mixing several liquid crystal compounds or liquid crystal-like compounds are used.

[Purpose of the invention]

It is an object of the present invention to provide new compounds suitable for use as components of liquid crystal compositions.

[Structure of the invention]

The present invention is based on the general formula (1) (wherein, R represents an alkyl group having 1 to 10 carbon atoms, and 2 represents F, CI, or Br). and m are positive integers from 0 to 9, and 1+m is 1 or 2.
A liquid crystal composition characterized by containing a halogeno aromatic compound represented by:

Examples of the compounds represented by the above general formula (1) by common names include trans-4-alkyl, ru(3-cyano-4-halogenophenyl)cyclohexane, and 4'-alkyl-3-cyano-4-nologe. nobiphenyl, 4I-alkyl-3-cyano-4-no)logno-p-terphenyl, trans-4-alkyl-(3-cyano-4-/S 0
1'/biphenylyl 1) cyclohexane, trans-4-alkyl-[trans-4-(3-cyano-4-
Halogenophenyl) cyclohexyl cyclohe
It is.

Among the compounds represented by the above general formula (1), those in which R is a linear alkyl group generally have a strong tendency to exhibit a liquid crystal phase,
When n is a branched alkyl group a Generally, the melting point is low and the compatibility with other compounds is good.

Moreover, those in which z (halogen) is F or Cl are preferable, and those in which F is particularly preferable because of their low viscosity.

The compound of the present invention represented by the general formula (■) can be produced by a known method shown in the following reaction formula.

(Jl) (V) That is, first, a 4-substituted acetanilide (■) obtained by a known method is reacted with bromine in an acetic acid solvent to obtain a bromo-substituted product (III). When the substituent 2 in the compound of formula (1) is F, the thermal decomposition reaction of diazonium tetrafluoroborate obtained by aminating and then diazotizing (■), the so-called Diman reaction (A, Roe, O
rganic Reactions+ 5°193,
(1949)) to obtain a fluorobromo-substituted product (transformation), which was mixed with cuprous cyanide in an appropriate basic solvent (e.g., N,N-dimethylformamide, pyridine,
The desired compound (1) is obtained by reacting the compound in N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, etc.).

In the compound of formula (1), substituent 2 is cl! in case of saliva)
Sandmeyer reaction (D, T, Mo
Chemical Reactions 4
2, 213 (1948)) to obtain a chlorobromo-substituted product QV), and react this product with cuprous cyanide in a basic solvent in the same manner as above to obtain the target compound (1).

When substituent 2 is nr in the compound of formula (1), (■)
The bromo-substituted product of the formula and cuprous cyanide are reacted in a basic solvent to obtain the cyano-substituted product (V) '&, which is aminated and then diazotized to obtain a diazonium salt and Ml copper bromide. The desired compound (I) & is obtained by Sandmeyer reaction with

The compound of the present invention represented by general formula (11) can be mixed with other liquid crystal compounds or liquid crystal compositions and used as a new liquid crystal composition. Examples of other liquid crystal compounds that can be used include known compounds represented by general formulas (1 to xxxii) shown below.

The amount of the compound of the present invention mixed with one or more liquid crystal compounds included in these known compound groups is preferably 1 to 30 wt%, more preferably 5 to 20 wt%, in the liquid crystal composition after mixing. It is. If the mixing amount is less than 1 wt%, the effect of the mixing will be unclear, and if the mixing amount exceeds 30 wt%, the viscosity of the liquid crystal composition will increase, which is not preferable.

R'-%Y (XVii) R'eCOO-X-Y (
xvai) (m=1.2) R'0(XyCOO-X-Y (XiX)R"(E and c
oo-x-y (xx) RI()-CH20-CJY(XXi) R'-C::
)-C)-Y (XXIi)nt eX Y (XX
m) u'sha cllll, ooy (xxiv) R'(hayY
(XXV) R'MX-Y (XXVi) CX)Y
(like) R'-C)Coo-()-Y(excitement)R'(
)-C2H4-1C)-Y(XX■)R'-4C>-C
2H, -()-X-Y (XxX)R'-()-02H
Pe>Y(xxxi)RI-4C)-C2H4(Σx-y
(Ad) Halogen, alkyl group or alkoxyl group. The alkyl group of R' and the alkyl group of Y may be the same or different. ) [Effects of the Present Invention] The compound of the present invention represented by the general formula (1) has large positive dielectric anisotropy and has good compatibility with other liquid crystal compounds.

The present invention greatly expands the selection of compounds that can be usefully used as components of liquid crystal compositions.

EXAMPLES The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Production of trans-4-propyl-(3-cyano-4-fluorophenyl)cyclohexane 4°-(trans-4-propylcyclohexyl)7ado, which corresponds to general formula (n) in the above reaction formula, Nilide m00F (0,386 mol) was dissolved in 500 MIK of acetic acid at 50-°C and bromine 93. lj' (0,578 mol) was added dropwise over 40 minutes, followed by reaction at 50° C. for 2 hours with stirring.

Recrystallization from d gives the general formula (II) in the above reaction formula.
2-promo-4-()trans-4-propylcyclohexyl)acetanilide 89F (yield: 68%) was obtained. The melting point of this product was 142.6°C.

This compound 701 corresponding to the above compound 701 was dissolved in 500 d of ethyl alcohol at 80° C., 100 d of concentrated hydrochloric acid was added, and the mixture was reacted under heating under reflux for 6 hours. After the reaction is complete, add 2 ml of water to the reaction mixture. The precipitated crystals were separated by F, washed with water, and dried to give 42.7 f of 2-promo-4-()lance-4-propylcyclohexyl)aniline hydrochloride (yield: $
62-1 (melting point 203.2°C) was obtained. 100 d of concentrated hydrochloric acid and 100 TIII of water were added to this hydrochloride, and while cooling to about 0°C and stirring, 11.2 t of sodium nitrite (
A 42% aqueous solution of tetrafluoroboric acid containing 0.162 mol) of 34? (0,162 mol) was slowly added, and the precipitate was diluted and dried to give 2-bromo-4-(trans-4-7'ropylcyclohexyl)benzenediazoniumtetrafluorobole) 42.6 F (yield 80%, melting point 142.1°C, decomposition point 148.5°C).

This diazonium salt was added to 200 d of dry toluene and heated to about 100°C for thermal decomposition.

After gas generation stopped, the reaction solution was allowed to cool to room temperature, and 10%
After treatment with 100 d of sodium hydroxide aqueous solution twice,
It was washed with water until the washing solution became neutral and dried over anhydrous sodium sulfate. From this toluene solution, the toluene was distilled off, and the resulting oily residue was distilled under reduced pressure to create trans-4-pyl-(3-bromo-4-fluorophenyl)cyclohexane corresponding to the general formula QV)23. 2 f C yield
i72 h, boiling point 145-148°C/2xsHt).

Compound 2C1 (56.8 mmol) corresponding to the above formula was dissolved in 100 d of N-methyl-2-pyrrolidone,
After adding 7.7 f (86.8 mmol) of cuprous cyanide and reacting by heating under reflux for 4 hours, about 50 d' of N-methyl-2-pyrrolidone was distilled off. This reaction solution was cooled to about 60°C, and anhydrous ferric chloride 132 (80 mm!
7 mol), 150,117 mol of water, and 10,117 mol of concentrated hydrochloric acid,
The reaction mixture was heated to 60° C. for 2 hours while stirring. After the reaction was completed, the separated oil was extracted with 100% of n-heptane, the extract was washed with water until the washings became neutral, and then dried over anhydrous sodium sulfate. The n-hebutane was distilled off from this extract, and the resulting oily residue was distilled under reduced pressure to obtain the desired product, trans-4-propyl-(3-
cyano-4-fluorophenyl)cyclohexane l 2
,8? (yield 78%, boiling point 178°C/3 times Hy) was obtained.

The infrared absorption spectrum and nuclear magnetic resonance spectrum of this product were consistent with the expected chemical structure.

Example 2 Nematic clearing point (N-!) of liquid crystal composition A having the following composition:
point) is 72.0℃, and the fat charge anisotropy value (Δε) is 11.6
．． The viscosity (η20) at 20°C is 27.8 cp. Thickness: 10 cm, assembled by facing substrates with transparent electrodes of tin oxide coated with silicon and rubbed.
When a T-N cell of tlm was filled with liquid crystal composition A to form a liquid crystal cell and its characteristics were measured at 20°C, the threshold voltage was 1.75V.

The saturation voltage was 2.40V.

85 wt% of liquid crystal composition (A) and 15 Wt of trans-4-propyl-(3-cyano-4-fluorophenyl)cyclohexane obtained in Example 1.
) point N-1 is 42℃, Δε is 12.5, and η2o is 30
It was cp. The threshold voltage of the liquid crystal cell filled with this liquid crystal composition (B) was 1.08V, and the saturation voltage was 1.58V.

that's all

Claims (2)

[Claims] (1) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R represents an alkyl group having 1 to 10 carbon atoms, and Z represents F
, Cl or Br halogen, l and m are each 0 or a positive integer, and l+m is 1 or 2). (2) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, B represents an alkyl group having 1 to 10 carbon atoms, and Z is F
, Cl or Br halogen, l and m are each 0 or a positive integer, and l + m is 1 or 2). Characteristic liquid crystal composition.