KR20000036036A - Liquid crystal materials - Google Patents

Abstract

PURPOSE: Provided are charily liquid crystal compounds that exhibit a low transition temperature from the crystalline to smectic and the smectic C phase over a wide temperature range, and that provide stable orientation over time. CONSTITUTION: The charily, laterally substituted compounds of formula (1) are liquid crystal compounds that exhibit a charily smectic C phase. Preferably, the compounds exhibit a charily smectic C phase over a broad temperature range, such as over a range of at least 20°C, more preferably at least 30°C, and most preferably over at least 40°C range. It is preferred that the compounds exhibit a charily smectic. C phase at low temperatures, including ambient temperatures. Accordingly, it is preferred that the lower end of the charily smectic C phase is 20°C or less, more preferably 10°C or less, and most preferably, 5°C or less.

Description

Liquid crystal compound

Liquid crystal displays have been commonly used in electronic equipment for many years. In general, commercial displays are operated in a twisted nematic (TN) or super twisted nematic (STN) manner. However, liquid crystal displays based on ferromagnetic methods are also known. Such display devices have excellent properties such as higher switching efficiency than TN and STN display devices. However, the ferromagnetic liquid crystal display device has a limited operating temperature range in spite of these advantages, and thus it is not widely used for commercial or consumer goods. In particular, in order to take advantage of the ferromagnetic effect, the liquid crystal material must exhibit a smetic C phase. Liquid crystal compounds exhibiting Smectic C phase retain their properties only in a narrow temperature range. Moreover, the Smectic C phase tends to appear only at relatively high temperatures, i.e., above ambient temperature. Therefore, it is impractical to design ferromagnetic liquid crystal display devices in general consumer electronic products.

Liquid crystal compounds include cyclohexane, cyclohexene, benzene, biphenyl and terphenyl compounds. Such compounds are disclosed in the following literature: Ferroelectrics 1991, vol. 114, p. 357; UP 04 216525 (1992); EP 86/00529 (1987); DE 3608500 (1987); WO 87/05015 (1987); WO 87/01717; WO 87/05017; DE 3706766; JP 88 300 885.6 (1988); J. Am. Che. Soc. 1986, vol. 108, p. 5210; GB 2181429; JP 05 17409; JP 07 258642 Many of these compounds do not show a Smectic C phase but instead only a nematic phase. Therefore, these compounds are useful only in TN or STN type display devices and do not function as ferromagnetic liquid crystal materials. Compounds exhibiting Smectic C phase suffer from the drawback of unstable orientation as well as the temperature limitations described above.

U.S. Patent 4,784,793 addresses some of the problems with ferromagnetic liquid crystal materials and suggests the use of terpenoid derivatives, such as esters of terpenoid alcohols, as smectic hosts or chiral dopants. US Pat. Nos. 5,382,380 and 5,494,605 all relate to p-terphenyl derivatives with fluorine substitution in the side chain. This compound is described as exhibiting a Smectic C phase over a wide temperature range.

However, the compounds according to the prior art are still not completely satisfactory and do not meet all the requirements required in some new applications of liquid crystal displays. In particular, there is a need for compounds that enable the formation of ferromagnetic liquid crystal mixtures having a low transition temperature from the crystal phase to the Smectic C phase, a wide Smectic C phase temperature range, and a stable orientation.

The present invention relates to a liquid crystal material used in a ferromagnetic liquid crystal display device. More specifically, the present invention relates to a chiral derivative having a side chain substituted as a derivative of a cyclohexane, benzene, biphenyl, terphenyl and quarterphenyl compound, a mixture thereof and a liquid crystal display device using the same.

An object of the present invention is to provide a chiral liquid crystal compound having a low transition temperature from a crystalline phase to a smectic C phase, exhibiting a smectic C phase over a wide temperature range, and exhibiting a stable orientation over time.

It is another object of the present invention to provide a ferromagnetic mixture which exhibits a Smectic C phase over a wide temperature range at low temperatures.

It is still another object of the present invention to provide a liquid crystal display device capable of operating at a very low temperature over a wide temperature range.

The above and other objects of the present invention are achieved by the chiral liquid crystal compound of formula (1).

R ^1- (A ¹ ) _a -Z ^1- (A ² ) _b- (Z ² ) _c- (A ³ ) _d -R ²

Wherein a, b, c and d are each independently 0 or 1;

R ¹ and R ² are each independently selected from the group consisting of the formulas S ¹ , S ² and S ³ :

Wherein Y ¹ , Y ² , Y ³ , and Y ⁴ are each independently hydrogen, alkyl, F, CN, CF ₃ or OCF ₃ , and n, p and k are each independently integers of 0 to 7, m And l are each independently 0 or 1, provided that at least one of R ¹ and R ² is a chiral radical;

Z ¹ and Z ² are each independently a ring selected from the group consisting of Formulas 2 to 11.

Wherein X is O, F, Cl, OH, CN or a group represented by the formulas L ¹ to L ⁶ :

Wherein Y ¹ , Y ² , Y ³ , Y ⁴ , n, p, k, m and l have the same meaning as in the formulas S ¹ -S ³ ;

A ¹ , A ² and A ³ are rings independently selected from the group consisting of Formulas 12-19:

Wherein X ¹ , X ² , X ³ , and X ⁴ are each H, F or Cl, and B and B ¹ are each a single bond, —CH ₂ CH ₂ —, —CH═CH—, —C≡C, -OCH ₂ -or -CH ₂ O;

Provided that any of X, X ¹ , X ² , X ³ and X ⁴ is F when the ring structure formed by any ^three of A ¹ , Z ¹ , A ² , Z ² and A ³ is terphenyl Does not represent.

The present invention relates to chiral liquid crystal compounds of formula (I):

Formula 1

R ^1- (A ¹ ) _a -Z ^1- (A ² ) _b- (Z ² ) _c- (A ³ ) _d -R ²

a, b, c and d is because each is 0 or 1. The compounds of formula (1) or may have a small number of the ring of one degree represented by Z ¹ or Z ¹ and A ¹ -A ³ and / or Z ² of the random It may have a plurality of rings represented by. When a is 0, the substituent R ¹ is directly bonded to the Z ¹ group. Likewise, if b, c and d are each 0, then the R ² group will be bonded directly to Z ¹ .

R ¹ and R ² are each represented by one of the formulas S ¹ -S ³ , provided that at least one of R ¹ and R ² is a chiral group. In this regard, although both R ¹ and R ² need not be chiral groups, such a case may be considered. Since at least one of R ¹ and R ² must be a chiral group, the compound of formula 1 is optically active.

In the formulas S ¹ -S ³ , the chiral component can be obtained by appropriately selecting a group for a pair of Y ¹ and Y ² or a pair of Y ³ and Y ⁴ , which is easy for those skilled in the art. Will be understood. The Y ¹ -Y ⁴ groups are each independently selected for R ¹ and R ² . That is, the Y ¹ group in the R ¹ may be the same as Y ¹ in the R ² group or may be different. The same is true for all other variables in the formulas S ¹ -S ³ , wherein the ones selected for R ¹ are independent of those selected for R ² . When Y ¹ , Y ² , Y ³ or Y ⁴ represents alkyl, it may be straight or branched and generally has 1 to 12 carbon atoms. More preferably, said alkyl group has 1 to 8 carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl and t-butyl. n, p and k are each an integer from 0 to 7, while m and l are 0 or 1, respectively. Preferably p and k are also 0 or 1.

Examples of R ¹ and R ² groups include 2-methylbutyl, 2-methylpentyl, 2-methylhexyl, 4-methylhexyl, citronelyl, citronelyloxy, 2-methylhexyloxy, 2-methyloctyloxy , 2-cyanobutyloxy and 2-fluorobutyloxy. Achiral R ¹ and R ² are octyl, octyloxy, butyl, hexyl, hexyloxy, nonyl, nonyloxy, decyl, decyloxy, 2-octyloxyethyl, 2-octyloxyethyloxy, heptyloxymethyl and heptyl Oxymethyloxy.

Z ¹ and Z ² each independently represent a six-membered ring selected from the group consisting of Formulas 2-11, each of which is substituted by a group X. Group X independently represents a group represented by O, F, Cl, OH, CN or the formula L ¹ -L ⁶ . When X is O, unlike OH, it is connected to the ring by a double bond. Therefore, X cannot be O in the rings of the formulas 4, 5 and 8-11. When Z ² is present (where c is 1), each group X is independently selected.

In the formulas L ¹ -L ⁶ , Y ¹ , Y ² , Y ³ and Y ⁴ , n, p, k, m and l have the same meanings as defined in the formulas S ¹ -S ³ . However, for greater emphasis and more clarity, it is again mentioned in the present application that groups such as Y ¹ may mean different things in each substituent and in each formula. Examples of L ¹ -L ⁶ are 2-methylbutyloxycarbonyl, 2-methylbutylcarbonyloxy, 2-methylhexyloxy, 2-methyloctyloxy, 2-methylbutyl, 2-methylbutyloxy, 2- Chlorobutylcarbonyloxy, ethyl and ethyloxy. As can be seen from the above formulas and those exemplified above, L ¹ -L ⁶ can represent a chiral group or an achiral group.

A ¹ -A ³ are each independently selected from the ring of formula 12-19. X ¹ -X ⁴ are independently selected for each of A ¹ -A ³ and are H, F or Cl. B and B ¹ are selected from a single bond, —CH ₂ CH ₂ —, —CH═CH—, —C≡C, —OCH ₂ —, and —CH ₂ O as the linking group.

The chiral compound in which the side chain is substituted, represented by the formula (1), is a liquid crystal compound exhibiting a chiral smectic C phase. The compound preferably exhibits a chiral smectic C phase over a wide temperature range of 20 ° C. or higher, more preferably 30 ° C. or higher, most preferably 40 ° C. or higher. It is also desirable to exhibit the chiral smectic C phase at low temperatures, including ambient temperature. Therefore, it is preferable that the minimum temperature of a chiral smectic C phase is 20 degrees C or less, More preferably, it is 10 degrees C or less, Most preferably, it is 5 degrees C or less. Smectic phase C temperature values can be measured by conventional methods known in the art, for example by heating the compound to an isotropic liquid phase, then cooling and reheating to observe the phase change and transition temperature. have. In the present application, the transition temperature was measured using a METTLER FP5 hotstage and a control unit together with a polarizing microscope, and these measured values were confirmed using a differential scanning calorimeter (Perkin-Elmer DSC-7). .

It is preferable that the compound of Formula 1 is a compound represented by one of Formulas 1.1 to 1.39 described later. In these formulae, R ³ and R ⁴ represent the formula L ¹ -L ⁶ group, while R ¹ , R ² and X ¹ -X ⁴ are as defined in formula (1).

R ¹ and R ² are each independently selected from the group consisting of the formulas S ¹ , S ² and S ³ .

Wherein Y ¹ , Y ² , Y ³ , and Y ⁴ are each independently hydrogen, alkyl, F, CN, CF ₃ or OCF ₃ , and n, p and k are each independently integers of 0 to 7, m And l are each independently 0 or 1, provided that at least one of R ¹ and R ² is a chiral radical;

Z ¹ and Z ² are each independently a ring selected from the group consisting of Formulas 2 to 11.

Compounds of formula (I) may be prepared by one of ordinary skill in the art without undue experimentation by conventional reactions known per se in the art and conventional and / or commercially available starting materials. have. However, the preferred reaction process is described below. The liquid crystal compound according to the present invention can be obtained by conversion of 3,6-disubstituted cyclohexane-2-enone. The synthesis of such starting compounds is shown in Scheme 1. For convenience and clarity, the compounds are described without the subscript a-d indicated, but such subscripts should be considered to be present.

The method consists of heating the acetoacetic acid ester with hydrochloric acid 4-substituted β-N-dimethylaminopropio-phenone in the presence of basic hydroxide. 3,6-disubstituted cyclohex-2-enone is converted to 3,6-disubstituted cyclohexanone (Formula 24) by reduction with hydrogen in the presence of 10% Pd / C.

As shown in Schemes 2 and 3, other compounds of Formula 1 may be readily obtained from compounds of Formulas 23 and 24. For convenience, mention again that the subscripts a-d are missing in these responsiveness. However, these reactivity includes the case where any one or more of a-d is zero.

Specifically, the 3,6-disubstituted cyclohex-2enones are correspondingly 4,4-disubstituted by aromatization in the presence of 200 ° C., 10% Pd / C or by heating in alcohol in the presence of iodine. Can be converted from 3-hydroxybiphenyl, terphenyl and quarterphenyl (Formula 27).

3,6-disubstituted cyclohexanone can be converted to the corresponding cis and trans alcohols (Formula 34) by reduction with NaBH ₄ or LiAlH ₄ in a suitable solvent.

Fluorine-substituted compounds (Formula 38-39) are prepared by heating the ketone (Formula 24) with diethylaminosulfur trifluoride in benzene or methylene chloride and the resulting difluoro derivative (Formula 36) is a base, preferably Preferably with KOH or alcoholate.

The cyanounsaturated compounds (42, 43) are treated with ketone (24) with acetone cyanohydrin in the presence of tertiary amines or alkali metal carbonates in dioxane or tetrahydrofuran, followed by the corresponding cyanoalcohol 3 Obtained by treatment with POCl ₃ in the presence of a primary aliphatic amine or pyridine. These isomeric compounds (formulas 42, 43) are separated by the crystallization method.

Chlorine substituted compounds (Formula 26, 30, 31) are obtained by heating ketones (Formula 23, 24) together with PCl ₅ , PCl ₃ in hexane or benzene. These isomeric compounds (formula 30, 31) are separated by crystallization methods or used in the form of isomer mixtures.

Compounds of formulas (25) and (32) are obtained by treating ketones (23, 24) with Grignard reagent in anhydrous ether solution. The corresponding alcohol in the toluene solution is then heated in the presence of a catalytic amount of acid, preferably in the presence of p-toluenesulfonic acid.

The compound of formula 36 is obtained by treating ketone (Formula 24) with triethyl orthoformate in the presence of p-toluenesulfonic acid in ethanol.

The chlorocyclohexane derivative (Formula 33) is obtained by treating the corresponding alcohol (Formula 34) with PCl ₅ , SOCl ₂ , PCl ₃ .

Fluorocyclohexane derivatives (Formula 33) are synthesized by treating alcohols (Formula 34) with diethylaminosulfur trifluoride (DAST) in methylenechloride at temperatures lower than 20 ° C.

Using the above-mentioned method, it is easy to obtain cyclohexene, cyclohexane, benzene, biphenyl, terphenyl and quarterphenyl derivatives which have been difficult to synthesize and study until now.

Compounds of Formula 1 are useful in liquid crystal displays including TN, STN and ferromagnetic LC displays. The compound of formula 1 is particularly useful for preparing compositions having a wide range of temperatures, as well as optical and dielectric anisotropy values, on the Smectic C phase. The composition according to the invention requires at least two kinds of compounds, at least one of which is a compound of formula (1). The compound included in the composition is entirely a compound of formula 1 or a mixture with other liquid crystal compounds.

Compositions containing a compound of formula 1 with two or three rings have a low or moderate clearing temtperature. Compositions containing a compound of formula 1 with four or five rings have an extended range of Smectic C phase, which is wider than 100 ° C. Such compositions are useful in ferromagnetic liquid crystal displays, TN, STN and active matrix displays. The high chemical stability and resistivity of these mixtures can stabilize the display performance.

It is preferred that the composition exhibits a chiral smectic C phase over a wide temperature range, preferably at least 40 ° C., as a ferromagnetic composition. At the same time, it is preferable that the lower limit temperature of a chiral smectic C phase is 10 degrees C or less, More preferably, it is -10 degrees C or less, Most preferably, it is -30 degrees C or less.

In one specific embodiment, one or more of the compounds of Formula 1 are combined with at least one liquid crystal pyrimidine derivative. Preferably, the pyrimidine derivative may exhibit a smectic C phase to form a ferromagnetic liquid crystal composition. Such compounds include phenyl-substituted pyrimidines such as 2-alkoxyphenyl-5-alkylpyrimidines, wherein the alkoxy and alkyl groups each contain 1-12 carbon atoms.

The composition of the present invention can be used in any conventional liquid crystal display device. As will be appreciated by those skilled in the art, such displays generally comprise two parallel electrodes, at least one of which is transparent and a layer of liquid crystal composition disposed between these electrodes. In more detail, the liquid crystal layer is generally disposed between two parallel plates, one of which is transparent and these parallel plates are again supported or surrounded by parallel electrodes. There may be one or more alignment layers, isolating layers and color filter layers between the parallel plates. In a specific preferred embodiment, the display device is operated by the ferromagnetic effect.

Hereinafter, the present invention will be described with reference to various embodiments. However, it should not be construed that the present invention is limited by the following examples.

Example 1

3- (4-octyloxyphenyl-6- (2-methylbutyl) cyclohex-2-enone (Formula 23)

0.1 mol of β-N-dimethylaminoethyl 4-octyloxypropiophenone hydrochloride, 0.12 mol of 2- (2-methylbutyl) acetoacetic ester, 0.25 mol of sodium isopropylate are dissolved in 200 ml of anhydrous isopropanol The mixture was refluxed for 5 hours. The mixture was cooled and acidified with 20% sulfuric acid solution. The oily substance was extracted from the mixture with diethyl ether. The extract was washed with water, dried over anhydrous Na ₂ SO _{4 and} filtered. The residue obtained after evaporation of the solvent was purified by crystallization in isopropanol. Yield 63%.

Using this method, the following compounds were prepared:

3-phenyl-6- (2-methylbutyl) cyclohex-2-enone,

3- (4-octyloxyphenyl) -6- (2-methylbutyl) cyclohex-2-enone,

3- (4- (2-methylbutyl) phenyl) -6-octylcyclohex-2-enone,

3- (4-citronellyloxyphenyl) -6-heptylcyclohex-2-enone,

3- (4-octyloxybiphenyl-4) -6- (2-methylbutyl) cyclohex-2-enone,

3- (4-citronellyloxybiphenyl-4) -6- (hexyl-21) cyclohex-2-enone,

3- (4- (methylbutyl) styryl-6-octylcyclohex-2-enone,

3- (4-citronellyloxystyryl) -6-heptylcyclohex-2-enone,

3- (4-octyloxystyryl) -6-citronellylcyclohex-2-enone,

3- (4-octyloxystyryl) -6-citronellylcyclohex-2-enone,

3- (4-pentylbiphenyl) -6-citronellylcyclohex-2-enone,

(m.p. 15 SmC 87 SmA 155 I)

1,4-bis- (3-citronellylcyclo-2-enonoyl-6) benzene,

4,4-bis- (3-citronellylcyclo-2-enonoyl-6) biphenyl,

3- (4-citronellyloxybiphenyl) -6- (2-cyanoethyl) cyclohex-2-enone,

3- (4- (2-methylbutyl) biphenyl) -6- (trans-4-butylcyclohexylethyl-2) cyclohex-2-enone, and

3- (trans-4- (2-methylbutyl) cyclohexylphenyl) -6- (trans-4-octylcyclohexyl) cyclohex-2-enone.

Example 2

3- (4-octyloxyphenyl-6- (2-methylbutyl) cyclohexanone (Formula 24)

0.1 mole of 3- (4-octyloxyphenyl-6- (2-methylbutyl) cyclohex-2enone and 5 g of KOH were dissolved in 150 ml of isopropanol and 50 in the presence of 1 g of catalyst (10% Pd / C). Hydrogenation was carried out using hydrogen gas at C until hydrogen was no longer absorbed, then the catalyst was filtered off, the solvent was evaporated, the residue was poured into water and extracted with hexane. The residue was then recrystallized several times in ethanol, yield 47%.

Using this method the following compounds were prepared:

3-phenyl-6- (2-methylbutyl) cyclohexanone,

3- (4-octyloxyphenyl) -6- (2-methylbutyl) cyclohexanone,

3- (4- (2-methylbutyl) phenyl) -6-octylcyclohexanone,

3- (4-octyloxybiphenyl-4) -6- (2-methylbutyl) cyclohexanone,

3- (2- (4-citronellyloxyphenyl) ethyl) -6-heptylcyclohexanone,

1,4-bis- (3- (2-methylhexyl) cycloxanoyl-6) benzene,

4,4-bis- (3- (2-methylbutyl) cycloxanoyl-6) biphenyl,

3- (4- (2-methylbutyl) biphenyl) -6- (trans-4-butylcyclohexylethyl-2) cyclohexanone, and

3- (trans-4- (2-methylbutyl) cyclohexylphenyl) -6- (trans-4-octylcyclohexyl) cyclohexanone.

Example 3

Synthesis of 1- (2-methylbutyl) 2-cyano-4- (4-octyloxybiphenyl) cyclohex-1-ene (Formula 42)

A mixture of 0.5 moles of 3-cis-citronellyl-6- (4-octyloxybiphenyl) cyclohexanone, 0.2 moles of acetone cyanohydrin, 0.2 moles of triethylamine and 40 ml of tetrahydrofuran was added for 24 hours. Left at room temperature. After addition of 100 ml of benzene, the mixture was diluted with water and diluted hydrochloric acid and dried over anhydrous sodium sulfate. Then the mixture was filtered and benzene was evaporated. 4 ml of pyridine and 0.1 mol of POCl ₃ were added to the residue and the resulting mixture was heated to boiling for 7 hours. The mixture was then poured into iced water and the product was extracted with benzene. The extract was diluted with water and diluted hydrochloric acid, then dried over MgSO ₄ and filtered. After evaporation of benzene, the residue was crystallized using a methanol-isopropanol mixed solution. Yield 38%.

Example 4

Synthesis of 1-cyano-3-trans- (4-octyloxybiphenyl) -6- (2-methylbutyl) cyclohex-1-ene (Formula 43)

A mixture of 0.05 mole 3-trans-citronellyl-6- (4-octyloxybiphenyl) cyclohexanone, 0.2 mole acetone cyanohydrin, 0.2 mole triethylamine and 40 ml tetrahydrofuran was added for 24 hours. Left at room temperature. After addition of 100 ml of benzene, the mixture was diluted with water and diluted hydrochloric acid and dried over anhydrous sodium sulfate. Then the mixture was filtered and benzene was evaporated. 4 ml of pyridine and 0.1 mol of POCl ₃ were added to the residue and the resulting mixture was heated to boiling for 7 hours. The mixture was then poured into iced water and the product was extracted with benzene. The extract was diluted with water and diluted hydrochloric acid, then dried over MgSO ₄ and filtered. After evaporation of benzene, the residue was crystallized using a methanol-isopropanol mixed solution. Yield 45%.

Example 5

Synthesis of 1- (2-methylbutyl) -2-cyano-4- (4-octyloxybiphenyl) cyclohexane (Formula 44)

A mixture of the corresponding cyano compounds (0.03 moles), prepared according to the method described in Example 4, was dissolved in a tetrahydrofuran-isopropanol (10: 1) mixed solution. 0.2 g of Pd / C (10%) was added to the resulting mixture and connected to a hydrogen source. The mixture was stirred until no more hydrogen was absorbed. The catalyst was filtered off, the solvent was evaporated off and the product was crystallized using a methanol-isopropanol mixed solution. Yield 38%.

Example 6

Synthesis of 1- (2-methylbutyl) -2-chloro-4- (4-octyloxybiphenyl) cyclohex-1-ene (Formula 30)

A mixture of 0.03 moles of cis-3- (2-methylbutyl) -6- (4-octyloxybiphenyl) cyclohexanone, 0.07 moles of PCl, NaSO and 50 ml of benzene is heated to boiling and cooled Treated with KOH 10% solution. The organic layer was then separated, washed with water, dried over anhydrous MgSO ₄ and filtered through an Al ₂ O ₃ layer. After evaporating the solvent, the oily liquid was crystallized using a methanol-isopropanol mixed solution. Yield 48%.

Example 7

Synthesis of 1- (2-methylbutyl) -2-methyl-4- (4-octyloxybiphenyl) cyclohex-1-ene (Formula 32)

To 0.04 mole methylmagnesium iodine solution in 200 ml of diethyl ether, 0.03 mole of cis-3-2- (2-methylbutyl) -6- (4-octyloxybiphenyl) cyclohexanone was added and stirred for 4 hours. It was. The resulting magnesium salt was decomposed using a 20% sulfuric acid solution, and the organic layer was separated and dried over Na ₂ SO ₄ . The solvent was then evaporated and 50 ml of toluene and a catalytic amount of p-toluenesulfonic acid were added to the residue and heated using an azeotropic head until the generation of water stopped. The mixture was then cooled and diluted with water. The toluene layer was separated, dried over Na ₂ SO _{4 and} filtered. The residue was dissolved in hexane and the crude product was purified by column chromatography and crystallized using isopropyl alcohol. Yield 70%.

Example 8

Synthesis of 1- (2-methylbutyl) -2-ethoxy-4- (4-octyloxybiphenyl) cyclohex-1-ene (Formula 36)

0.05 moles of cis-3-2- (2-methylbutyl) -6- (4-octyloxybiphenyl) cyclohexanone, 0.15 moles of ethyl ester of ortho formic acid, catalytic amount of p-toluenesulfonic acid and 150 ml of ethyl The mixture of alcohols was stirred for 6 hours. The mixture was then diluted with water and extracted with benzene. The benzene layer was separated, washed with water and dried over Na ₂ SO ₄ . After evaporation of benzene, the oily residue was dissolved in hexane, eluted on a column packed with silica gel and the fractions collected. Based on chromatographic analysis, the fractions containing the pure product were collected and the solvent was evaporated. Yield 48%.

Example 9

Synthesis of trans-1- (2-methylbutyl) -2,2-difluoro-4- (4-octyloxybiphenyl) cyclohexane (Formula 37)

A mixture of 0.01 mol of trans-3- (2-methylbutyl) -6- (4-octyloxybiphenyl) cyclohexanone, 0.01 mol of diethylaminosulfur trifluoride (DAST) and 15 ml of benzene was added for 24 hours. Heated to boiling. The mixture was then poured into water, the benzene layer was separated, washed with water, dried over MgSO ₄ and filtered. The crude product remaining after evaporation of the solvent was crystallized with isopropanol. Yield 60%.

Example 10

Synthesis of 1- (2-methylbutyl) -2-fluoro-4- (4-octyloxybiphenyl) cyclohex-1-ene (Formula 39)

A mixture of 0.01 mol of trans-1- (2-methylbutyl) -2,2-difluoro-4- (4-octyloxybiphenyl) cyclohexane, 0.05 mol of KOH and 30 ml of ethylene glycol was added for 8 hours. After stirring at 130 ° C., the mixture was diluted with water and extracted with benzene. The benzene layer was washed with water then dried over MgSO ₄ and filtered. The crude product remaining after evaporation of the solvent was crystallized with isopropanol. Yield 47%.

Example 11

Synthesis of 2- (2-methylbutyl) -5- (4-octyloxybiphenyl) cyclohexan-1-ol (Formula 34)

A mixture of 0.05 mol of trans-3- (2-methylbutyl) -6- (4-octyloxybiphenyl) cyclohexanone, 0.05 mol of sodium borohydride and 100 ml of isopropyl alcohol was added at 50-60 ° C. Stir for hours. The reaction mixture was acidified with hydrochloric acid and extracted with ether. The ether extract was washed with water and then dried over MgSO ₄ . After evaporation of the solvent in vacuo the crude product was crystallized with hexane. Yield 85%.

Example 12

Synthesis of 1- (2-methylbutyl) -2-fluoro-4- (4-octyloxybiphenyl) cyclohexane (Formula 40)

0.05 mol of diethylaminosulfur trifluoro in a solution in which 0.05 mol of 2- (2-methylbutyl)-(4-octyloxybiphenyl) cyclohexan-1-ol is dissolved in 15 ml of CHCl at −70 ° C. Ride (DAST) was added. The cooling was then stopped, the temperature of the mixture was raised to room temperature and poured into water, allowing delamination to occur. The organic layer was dried over Na ₂ S0 ₄ and filtered. After evaporation of the solvent, the crude product was recrystallized with ethanol. Yield 50%.

Example 13

Synthesis of 4- (2-methylbutyl) -3-hydroxy-4-octyloxyterphenyl (Formula 27)

0.1 mole of 3- (4-octyloxyphenyl-6- (2-methylbutyl) cyclohex-2-enone was hydrogenated in the presence of 1 g of catalyst (10% Pd / C) at 200 ° C. The reaction mixture was ether After dissolving in, the catalyst was filtered off and the solvent was evaporated The residue was recrystallized several times with toluene Yield 47%.

Example 14

Synthesis of 1- (2-methylbutyl) -2-chloro-4- (4-octyloxybiphenylcyclohexane (Formula 33)

A mixture of 0.05 mol of 2- (2-methylbutyl) -5- (4-octyloxybiphenyl) cyclohexan-1-ol and 0.05 mol of SOCl ₂ in 35 ml of benzene was mixed at 30 ° C. for 0.05 hours. Heated. Then heating was stopped and the mixture was poured into water. The organic layer was separated, washed with water, dried over anhydrous MgSO ₄ and filtered. After evaporation of the solvent, the oily liquid was crystallized using a methanol-isopropanol mixed solution. Yield 57%.

Example 15

Synthesis of 4- (2-methylbutyl) -3-chloro-4-octyloxyterphenyl (Formula 26)

0.1 mol of 3- (4-octyloxybiphenyl) -6- (2-methylbutyl) cyclohex-2-enone and 0.01 mol of PCl ₅ were dissolved in 30 ml of benzene and boiled for 4 hours. Then the heating was stopped and the mixture was poured into KOH 10% solution. The organic layer was separated, washed with water, dried over anhydrous MgSO ₄ and filtered. After evaporation of the solvent, the oily liquid was crystallized using an isopropanol mixed solution. Yield 65%.

Using this method the following compounds were prepared:

4-citronelin-3-chloro-4-octyloxyterphenyl

m.p. 5 SmC 67 SmA 105 I

Example 16

Synthesis of 4- (2-methylbutyl) -3-citronellyloxy-4-octyloxyterphenyl (Formula 29)

A mixture of 0.01 mole 4- (2-methylbutyl) -3-hydroxy-4-octyloxyterphenyl, 0.012 mole citronelyl bromide, 0.02 mole KOH and 50 ml isopropyl alcohol was boiled for 5 hours. . Then washed with water, dried over anhydrous MgSO ₄ and filtered. The residue remaining after evaporation of the solvent was crystallized with isopropanol. Yield 64%.

Example 17

Synthesis of 2- (2-methylbutyl) -5- (4-octyloxybiphenyl) -1- (2-methylbutylcarbonyloxy) cyclohexane (Formula 35)

In a solution in which 0.01 mol of 2- (2-methylbutyl) -5- (4-octyloxybiphenyl) cyclohexan-1-ol and 0.12 mol of 2-methylbutyrol chloride are dissolved in 50 ml of anhydrous ether, 0.02 mole of pyridine was added. After 12 hours, the reaction mixture was acidified with hydrochloric acid and then separated. The ether layer was washed with water and then dried over MgSO ₄ . The solvent was removed under vacuum and the crude product was crystallized with ethanol. Yield 45%.

Example 18

Mixture A with the following composition:

2- (4-heptyloxyphenyl) -5-heptylpyrimidine-5%

2- (4-octyloxyphenyl) -5-heptylpyrimidine-10%

2- (4-nonyloxyphenyl) -5-heptylpyrimidine-15%

2- (4-octyloxyphenyl) -5-octylpyrimidine-20%

2- (4-decyloxyphenyl) -5-octylpyrimidine-30%

2- (4-hexyloxyphenyl) -5-nonylpyrimidine-20%

m.p. 10 SmC 51 SmA 63 N 69 I

Example 19

Mixture B of the following composition:

Mixture A-90%

4-citronellyl-3-chloro-4-octyloxyterphenyl-10%

m.p. -5 SmC 59 SmA 61 N 65 I

Although the present invention has been described in detail by the above embodiments, it will be apparent that variations are possible in various ways. Such modifications should be considered as not departing from the spirit and scope of the present invention, and all modifications apparent to those skilled in the art should be construed as falling within the scope of the appended claims.

Compounds of Formula 1 are useful in liquid crystal displays, including TN, STN and ferromagnetic liquid crystal displays. The compound of formula 1 is particularly useful for making compositions having a wide temperature range as well as optical anisotropy and dielectric anisotropy. The compound of the present invention can be used in all conventional liquid crystal display devices.

Claims (15)

A chiral liquid crystal compound represented by formula (1): R ^1- (A ¹ ) _a -Z ^1- (A ² ) _b- (Z ² ) _c- (A ³ ) _d -R ² Wherein a, b, c and d are each independently 0 or 1; R ¹ and R ² are each independently selected from the group consisting of the formulas S ¹ , S ² and S ³ : Wherein Y ¹ , Y ² , Y ³ , and Y ⁴ are each independently hydrogen, alkyl, F, CN, CF ₃ or OCF ₃ , and n, p and k are each independently integers of 0 to 7, m And l are each independently 0 or 1, provided that at least one of R ¹ and R ² is a chiral radical; Z ¹ and Z ² are each independently a ring selected from the group consisting of Formulas 2 to 11. Wherein X is O, F, Cl, OH, CN or a group represented by the formulas L ¹ to L ⁶ : Wherein Y ¹ , Y ² , Y ³ , Y ⁴ , n, p, k, m and l have the same meaning as in the formulas S ¹ -S ³ ; A ¹ , A ² and A ³ are rings independently selected from the group consisting of Formulas 12-19: Wherein X ¹ , X ² , X ³ , and X ⁴ are each H, F or Cl, and B and B ¹ are each a single bond, —CH ₂ CH ₂ —, —CH═CH—, —C≡C, -OCH ₂ -or -CH ₂ O; Provided that any of X, X ¹ , X ² , X ³ and X ⁴ is F when the ring structure formed by any ^three of A ¹ , Z ¹ , A ² , Z ² and A ³ is terphenyl Does not represent. A compound according to claim 1, wherein both R ¹ and R ² are chiral radicals. A compound according to claim 1, wherein X is represented by one of formulas L ¹ -L ⁶ . The compound of claim 3, wherein both c and d are zero. The compound of claim 1, wherein at least one of a and b is 1. A compound according to claim 1, wherein R ¹ and R ² are each independently represented by a formula S ¹ . The compound of claim 1, wherein the compound exhibits a chiral smectic C phase. 8. A compound according to claim 7, wherein said compound exhibits a chiral smectic C phase over a temperature range of at least 40 < 0 > C. 8. The compound according to claim 7, wherein the lower limit temperature of the chiral smectic C phase of the compound is 10 ° C or less. Liquid crystal composition comprising at least one compound represented by Formula 1: R ^1- (A ¹ ) _a -Z ^1- (A ² ) _b- (Z ² ) _c- (A ³ ) _d -R ² Wherein a, b, c and d are each independently 0 or 1; R ¹ and R ² are each independently selected from the group consisting of the formulas S ¹ , S ² and S ³ : Wherein Y ¹ , Y ² , Y ³ , and Y ⁴ are each independently hydrogen, alkyl, F, CN, CF ₃ or OCF ₃ , and n, p and k are each independently integers of 0 to 7, m And l are each independently 0 or 1, provided that at least one of R ¹ and R ² is a chiral radical; Z ¹ and Z ² are each independently a ring selected from the group consisting of Formulas 2 to 11. Wherein X is O, F, Cl, OH, CN or a group represented by the formulas L ¹ to L ⁶ : Wherein Y ¹ , Y ² , Y ³ , Y ⁴ , n, p, k, m and l have the same meaning as in the formulas S ¹ -S ³ ; A ¹ , A ² and A ³ are rings independently selected from the group consisting of Formulas 12-19: Wherein X ¹ , X ² , X ³ , and X ⁴ are each H, F or Cl, and B and B ¹ are each a single bond, —CH ₂ CH ₂ —, —CH═CH—, —C≡C, -OCH ₂ -or -CH ₂ O; Provided that any of X, X ¹ , X ² , X ³ and X ⁴ is F when the ring structure formed by any ^three of A ¹ , Z ¹ , A ² , Z ² and A ³ is terphenyl Does not represent. The composition of claim 10 further comprising at least one pyrimidine compound. The composition according to claim 1, wherein the composition exhibits a chiral smectic C phase and the lower limit temperature of the chiral smectic C phase is -30 ° C. 13. The composition of claim 12 wherein the composition exhibits a chiral smectic C phase over a temperature range of at least 40 ° C. Two parallel plate electrodes, at least one of which is transparent; And A liquid crystal display device comprising a liquid crystal layer disposed between the parallel plates and containing the composition of claim 10. The liquid crystal display of claim 14, further comprising at least one of an alignment layer and a separation layer between the parallel plates.