Novel optically active benzene derivatives, process for producing the same and liquid-crystalline composition containing said derivatives as liquid-crystalline compound and light switching elements

Abstract: Disclosed are herein optically active benzene derivatives represented by the formula (I): (wherein R₁ represents an alkyl group having 3 to 20 carbon atoms; Y represents -O-, -COO- or -OCO-; m, p and s each represents a number of 0 or 1; Ar represents provided that when p is 1 Ar represents when p is 0 Ar represents X represents -COO- or -OCO-; Z represents wherein q represents a number of 1 to 5, t represents a number of 0 to 5, ℓ represents a number of 1 or 2, u represents a number of 0 or 1 and * indicates asymmetric carbon atom; provided that when Ar represents Z represents when P is 0 Z represents with the proviso that when t is 0 Ar represents R₂ represents an alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms; provided that when u is 0, R₂ represents an optically active alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms), preparation processes therefor, liquid crystal composition containing such benzene derivatives as liquid-crystalline compound, and a light switching element using said liquid crystal composition as liquid crystal element.

Description: This invention relates to the optically active benzene derivatives represented by the general formula (I): wherein R 1 represents an alkyl group having 3 to 20 carbon atoms; Y represents -O-, -COO- or -OCO-; m represents an integer of 0 or 1; Ar represents or Z represents wherein t represents a number of 0 to 5 and * indicates an asymmetric carbon atom; and R 2 represents an alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms, a process for producing the same, a liquid-crystalline composition containing said derivatives as liquid-crystalline compound, and light switching elements utilizing the liquid crystal compositions containing said derivatives. The term "liquid-crystalline compound" is used in this specification to refer to the liquid-crystalline compound of the broad sense, including those which may not have been confirmed to take a liquid crystal phase per se but can be utilized effectively as a liquid crystal composition. Image display devices using liquid crystal are now practically used in various fields. TN (twisted nematic) type liquid crystal display is known as one of these display systems. This display system has the advantages that its power consumption is low and it is soft to the eye because of the light-receiving type (the display panel itself is not luminous). Display by this system, however, is not always satisfactory in the aspect of response speed. As a system which is capable of high speed response, a display device utilizing the optical switching performance of ferroelectric liquid crystal has been proposed (Applied Physics Letters, 36, 899 (1980)) and is attracting attention. In view of its molecular configuration, ferroelectric liquid crystal is considered to belong to the type of liquid crystal having chiral smectic C phase (hereinafter referred to as S C * phase) or chiral smectic H phase (S H * phase). With its high speed response characteristics, such ferroelectric liquid crystal is expected to find its use not only for display devices such as liquid crystal televisions but also as materials for electronic elements such as optical printer head, photo-Fourier transformation element, etc. A ferroelectric liquid crystal material to be used in a ferroelectric liquid crystal indicating element practically utilized is required to have a number of characteristics, however, at present, one kind of compound singly can not satisfy these requirements, thus, it is necessary to use a ferroelectric liquid crystal composition obtained by mixing several kinds of liquid crystal compounds or non-liquid crystal compounds. Further, in addition to the ferroelectric liquid crystal composition comprising ferroelectric liquid crystal compounds only, Japanese Unexamined Patent Publication No. 195187/1986 has reported that a compound and a composition exhibiting a phase of smectic C, F, G, H or I which is non-chiral (hereinafter abbreviated as a phase of Sc or the like) are used as basic substances and one kind or plural kinds of compounds exhibiting a ferroelectric liquid crystal phase are mixed with the above substance to obtain a liquid crystal composition which is ferroelectric as a whole. Further, there has been found a report that compounds and compositions exhibiting a phase of Sc or the like are used as basic substances and one kind or plural kinds of compounds which are optically active but exhibit no ferroelectric liquid crystal phase are mixed therewith to make them a ferroelectric liquid crystal composition as a whole (Mol. Cryst. Liq. Cryst. 89. 327 (1982). US-A-4,876,026 discloses optically active 2-methylbutyrate derivatives which have a biphenyl or pyrimidinyl moiety. These compounds are said to be capable of imparting a spontaneous polarization value to achiral smectic compositions. EP-A-0,270,243 discloses optically active compounds containing a biphenyl moiety which are said to be useful as components of ferroelectric liquid crystal mixtures. Summarizing the above described, it is understood that one kind or plural kinds of compounds which are optically active, irrespectively of the compounds exhibiting a ferroelectric liquid crystal phase or not, can be mixed with basic substances to constitute a ferroelectric liquid crystal composition. However, it is preferable that the optically active substances desirably exhibit a liquid crystal phase, and even if they exhibit no liquid crystal phase, they preferably have a structure similar to a liquid crystal substance, namely, they are preferably the so-called pseudo liquid crystal substance. However, there has yet been found no liquid crystal material which shows spontaneous polarization necessary for high-speed response and liquid crystal properties in the low temperature region. In view of the above, the present inventors have made studies for developing a liquid crystal compound which can be widely applied to various types of display systems such as mentioned above, and as a result they found out novel optically active benzene derivatives and achieved the present invention. The present invention provides the novel optically active benzene derivatives represented by the above-described general formula (I). Such optically active benzene derivatives have been unknown in the prior art and disclosed for the first time by the present inventors. The compounds represented by the formula (I-d) : (wherein R 1 , R 2 , Y and m have the meanings given above; Z" represents wherein t represents a number of 0 to 5 and * indicates asymmetric carbon atom; and Ar" represents can be produced, for instance, by reacting optically active aromatic alcohols represented by the formula (VI): (wherein R 1 , Y, Ar", Z" and m have the meanings given above) with alkylating reagents represented by the formula (IX): Q - R 2 wherein R 2 has the meanings given above; Q represents a halogen atom or -OSO 2 R"' wherein R"' represents a lower alkyl group or a phenyl group optionally substituted by alkyl groups. The optically active aromatic alcohols (VI) containing an asymmetric carbon, which are used as starting material in the above reactions, can be produced, for instance, a ○ t = 0 b ○ t = 1 - 2 c ○ t = 3 - 5 The alkylating reagents (IX) used as another starting material in said reactions are mostly the known compounds and can be produced according to the methods disclosed in the literature. The substituent R 1 in the formula (VI) representing the optically active aromatic alcohols can be, for example, an alkyl such as propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl and eicosyl. The substituent R 2 in the formula (IX) representing alkylating reagents can be, for example, a straight-chain alkyl such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicocyl and the like, a branched alkyl such as 1-methylethyl, 2-methylbutyl, 3-methylpentyl, 4-methylhexyl, 5-methylheptyl, 6-methyloctyl, 1-methylpropyl, 1-methylbutyl, 1-methylpentyl, 1-methylhexyl, 2-ethylbutyl, 1-methylheptyl, 2,3-dimethylbutyl, 2,3,3-trimethylbutyl, 2-methylpentyl, 2,3-dimethylpentyl, 2,4-dimethylpentyl, 2,3,3,4-tetramethylpentyl, 2-methylhexyl, 3-methylhexyl, 2,5-dimethylhexyl, 2-methylheptyl, 2-methyloctyl, 2-trihalomethylpentyl, 2-trihalomethylhexyl, 2-trihalomethylheptyl, 2-halopropyl, 3-halo-2-methylpropyl, 2,3-dihalopropyl, 2-halobutyl, 3-halobutyl, 2,3-dihalobutyl, 2,4-dihalobutyl, 3,4-dihalobutyl, 2-halo-3-methylbutyl, 2-halo-3,3-dimethylbutyl, 2-halopentyl, 3-halopentyl, 4-halopentyl, 2,4-dihalopentyl, 2,5-dihalopentyl, 2-halo-3-methylpentyl, 2-halo-4-methylpentyl, 2-halo-3-monohalomethyl-4-methylpentyl, 2-halohexyl, 3-halohexyl, 4-halohexyl, 5-halohexyl, 2-haloheptyl, 2-halooctyl ("halo" in the alkyl group described above represents fluorine, chlorine, bromine or iodine), and the like, or an alkyloxyalkyl such as methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl, methoxyhexyl, methoxyheptyl, methoxyoctyl, methoxynonyl, methoxydecyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, ethoxybutyl, ethoxypentyl, ethoxyhexyl, ethoxyheptyl, ethoxyoctyl, ethoxynonyl, ethoxydecyl, propoxymethyl, propoxyethyl, propoxypropyl, propoxybutyl, propoxypentyl, propoxyhexyl, propoxyoctyl, propoxydecyl, butoxymethyl, butoxyethyl, butoxypropyl, butoxybutyl, butoxypentyl, butoxyhexyl, butoxyheptyl, butoxynonyl, pentyloxymethyl, pentyloxyethyl, pentyloxypropyl, pentyloxybutyl, pentyloxypentyl, pentyloxyoctyl, pentyloxydecyl, hexyloxymethyl, hexyloxyethyl, hexyloxypropyl, hexyloxybutyl, hexyloxypentyl, hexyloxyhexyl, hexyloxyoctyl, hexyloxynonyl, hexyloxydecyl, heptyloxymethyl, heptyloxyyethyl, heptyloxypropyl, heptyloxypentyl, octyloxymethyl, octyloxyethyl, decyloxymethyl, decyloxyethyl, decyloxypropyl and the like. In said branched alkyls, the branching carbon may be optically active one. Meanwhile, those which are capable of becoming optical active among the alkyl groups or alkoxyalkyl groups which may be substituted with a halogen atom may be an optically active group. An ordinary etherification method can be applied for the reaction of optically active aromatic alcohols (VI) and alkylating reagents (IX), and such reaction can be carried out in the presence of a solvent by using a basic substance. As the basic substance, there may be exemplified, for example, an alkaline metal hydride such as sodium hydride and potassium hydride, an alkaline metal such as lithium, sodium and potassium, an alkaline metal alcoholate such as sodium ethylate and sodium methylate, an alkaline metal carbonate such as sodium carbonate and potassium carbonate and lithium butyl. The amount of the above basic substance required is one equivalent amount or more and preferably within the range of 1 to 5 equivalent amounts relative to the optically active alcohols, although the upper limit thereof is not particularly limited. Alkylating reagents (IX) to be used in this reaction are halides such as a chloride, a bromide, an iodide or sulfates (methanesulfonic ester, ethanesulfonic ester, benzene sulfonic ester and toluenesulfonic ester) having an alkyl group or an alkoxyalkyl group of 1 to 20 carbon atoms, which may be substituted with a halogen atom, as exemplified as the above. These alkyl group or alkoxyalkyl group of 1 to 20 carbon atoms which may optionally be substituted with a halogen atom may be an optically active group. These halides or sulfates having an optically active group are derived from the corresponding alcohols, and some of the optically active alcohols can easily be obtained by asymmetric reduction of the corresponding ketones with an asymmetric metal catalyst, a microorganism or an enzyme. Some of the alcohols exist in nature or can be derived from the following optically active amino acids and optically active oxy acids obtainable by optical resolution: valine, leucine, isoleucine, phenylalanine, threonine, allothreonine, homocerin, alloisoleucine, tert-leucine, 2-aminobutyric acid, norvaline, norleucine, ornithine, lysine, hydroxylysine, phenylglycine, aspartic acid, glutamic acid, mandelic cid, toropic acid, 3-hydroxybutyric acid, malic acid, tartaric acid and isopropylmalic acid. The amount of such an alkylating agent (IX) used is not limited so long as it is one equivalent amount or more and usually within the range of 1 to 5 equivalent amounts relative to the optically active aromatic alcohols (VI). As the reaction solvent, in addition to the above exemplified solvents, polar solvents such as dimethylsulfoxide, hexamethyl triamide phosphate, N-methylpyrrolidone can be used. The reaction temperature may be usually -50°C to 120°C, preferably within the range of -30°C to 100°C. After completion of the reaction, optically active benzene derivatives of the general formula (I-d) can be obtained in a good yield according to the ordinary separation methods such as procedures of extraction, separation, concentration and the like, and if necessary, derivatives can be purified by column chromatography, recrystallization. Specific examples of optically active benzene derivatives (I-d) are shown below. 2-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)phenyl)pyrimidine, 2-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)oxyphenyl}pyrimidine, 2-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)carbonyloxyphenyl}pyrimidine, 2-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)oxycarbonylphenyl}pyrimidine, 5-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbon atoms)phenyl}pyrimidine, 5-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbon atoms)oxyphenyl}pyrimidine, 5-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbon atoms)carbonyloxyphenyl}pyrimidine, 5-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbon atoms)oxycarbonylphenyl}pyrimidine, 2-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}phenyl]-5-alkyl(of 3 to 20 carbon atoms)pyrimidine, 2-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}phenyl]-5-alkyl(of 3 to 20 carbon atoms)oxypyrimidine, 2-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}phenyl]-5-alkyl(of 3 to 20 carbon atoms)carbonyloxypyrimidine, 5-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}phenyl]-2-alkyl(of 3 to 20 carbon atoms)pyrimidine, 5-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}phenyl]-2-alkyl(of 3 to 20 carbon atoms)oxypyrimidine, 5-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl)phenyl]-2-alkyl(of 3 to 20 carbon atoms)carbonyloxypyrimidine, 5-[4-{1-Alkyl(of 1 to 20 carbon atoms)oxyethyl}phenyl]-2-alkyl(of 3 to 20 carbon atoms)oxycarbonylpyrimidine, 2-{1-Methyl-2-alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)oxyphenyl)pyrimidine, 2-{1-Methyl-2-alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)carbonyloxyphenyl}pyrimidine, 2-{1-Methyl-2-alkyl(of 1 to 20 carbon atoms)oxyethyl}-5-{4-alkyl(of 3 to 20 carbon atoms)oxycarbonylphenyl}pyrimidine, 5-{1-Methyl-2-alkyl(of 1 to 20 carbonatoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbonatoms)phenyl}pyrimidine, 5-{1-Methyl-2-alkyl(of 1 to 20 carbonatoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbonatoms)oxyphenyl}pyrimidine, 5-{1-Methyl-2-alkyl(of 1 to 20 carbonatoms)oxyethyl}-2-{4-alkyl(of 3 to 20 carbon atoms)carbonyloxyphenyl)pyrimidine, 5-{1-Methyl-2-alkyl(of 1 to 20 carbonatoms)oxyethyl)-2-{4-alkyl(of 3 to 20 carbon atoms)oxycarbonylphenyl}pyrimidine, 2-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon atoms)oxyethyl}-phenyl]-5-alkyl(of 3 to 20 carbon atoms)pyrimidine, 2-[4-{1-Methyl-2-alkyl(of 1 to 20 carbonatoms)oxyethyl}-phenyl]-5-alkyl(of 3 to 20 carbon atoms)oxypyrimidine, 2-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon atoms)oxyethyl}-phenyl]-5-alkyl(of 3 to 20 carbon atoms)carbonyloxypyrimidine, 2-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon atoms)oxyethyl}-phenyl]-5-alkyl(of 3 to 20 carbon atoms)oxycarbonylpyrimidine, 5-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon-atoms)oxyethyl}-phenyl]-2-alkyl(of 3 to 20 carbon atoms)pyrimidine, 5-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon-atoms)oxyethyl}-phenyl]-2-alkyl(of 3 to 20 carbon atoms)oxypyrimidine, 5-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon-atoms)oxyethyl}-phenyl]-2-alkyl(of 3 to 20 carbon atoms)carbonyloxypyrimidine, 5-[4-{1-Methyl-2-alkyl(of 1 to 20 carbon-atoms)oxyethyl}-phenyl]-2-alkyl(of 3 to 20 carbon atoms)oxycarbonylpyrimidine, Compounds in which "1-methyl-2-alkyl(of 1 to 20 carbon atoms)-oxyethyl" in the above exemplified compounds is replaced with any one of: "1-methyl-3-alkyl(of 1 to 20 carbon atoms)oxypropyl", "1-methyl-4-alkyl(of 1 to 20 carbon atoms)oxybutyl", "1-methyl-5-alkyl(of 1 to 20 carbon atoms)oxypentyl" and "1-methyl-6-alkyl(of 1 to 20 carbon atoms)oxyhexyl", Compounds in which "1-methyl-2-alkyl(of 1 to 20 carbon atoms)-oxyethyl" group which is a substituent on the phenyl group in the above exemplified compounds is replaced with any one of: "1-methyl-3-alkyl(of 1 to 20 carbon atoms)oxypropyl", "1-methyl-4-alkyl(of 1 to 20 carbon atoms)oxybutyl", "1-methyl-5-alkyl(of 1 to 20 carbon atoms)oxypentyl" and "1-methyl-6-alkyl(of 1 to 20 carbon atoms)oxyhexyl" group. Here, "alkyl (of 3 to 20 carbon atoms)" means an alkyl group having 3 to 20 carbons and "alkyl (of 1 to 20 carbon atoms)" means an alkyl group or an alkoxyalkyl group having 1 to 20 carbons and may be substituted with a halogen atom, and they are substituents exemplified above. When the thus obtained optically active benzene derivatives represented by the general formula (I) are utilized as a constituent element of liquid crystals, particularly the constituent element of the ferroelectric liquid crystals, the substituent R 2 is preferably an alkyl group or an alkoxyalkyl group from a view of optical stability in practice. Further, in the ferroelectric liquid crystals, for permitting them to exert rapid response property which is a characteristic feature thereof, liquid crystals having a smaller viscosity coefficient are preferred. For permitting liquid crystals to exert the rapid response property, a compound having a large spontaneous polarization is preferably used and in this case, s = 1 is preferred. Utilization of the optically active benzene derivatives represented by the general formulae (I-d) as a liquid crystal composition is effective for lowering the temperature range of the liquid crystal phase without enhancing the viscosity, even if said benzene derivatives themselves exhibit no liquid crystal phase. Further, the response speed can be enhanced because of excellent activity for enhancing spontaneous polarization in liquid crystal composition. The liquid crystal composition of the present invention is one containing at least one kind of optically active benzene derivatives represented by the general formula (I) as the formulating component. In this case, the optically active benzene derivative represented by the general formula (I) is usually used so as to give a ratio of 0.1 to 99.9% by weight preferably 1 to 99% by weight based on the resulting liquid crystal composition. Further, such a liquid crystal composition is used to be effectively utilized also as a liquid crystal element, for example, a light switching element, and as the method of use of the liquid crystal composition in this case, a method which has heretofore been known can be applied as such without any particular limitation. Thus, according to the present invention, novel optically active derivatives represented by the general formula (I) can be easily obtained with a good yield, and besides can be effectively utilized as a liquid crystal composition and further as a liquid crystal element employing the same, due to excellent characteristics of said derivatives as a liquid crystal compound. Preparation Example (starting-material compound (VI)) To a mixed solvent of 200 ml of ethanol and 100 ml of chloroform were added 35.5 g (0.1 mole) of 2-(4-acetylphenyl)-5-decyloxypyrimidine, and while maintaining the temperature at 30 to 35°C, 2.65 g (0.07 mole) of sodium borohydride were gradually added thereto. After stirring at the same temperature for 4 hours, the reaction mixture was poured into 500 ml of water and extracted with 400 ml of ethyl acetate. The organic phase was washed sufficiently, dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain 35.6 g (yield: 99.9 %) of 2-{4-(1-hydroxyethyl)phenyl}-5-decyloxypyrimidine. To a solution of 32.1 g (0.09 mole) of the thus obtained 2-{4-(1-hydroxyethyl)phenyl}-5-decyloxypyrimidine, 200 ml of toluene and 100 ml of pyridine were added 12.2.g (0.12 mole) of acetlc anhydride and 1 g of 4-dimethylaminopyridine, and while maintaining the temperature at 30 to 40°C, reaction was carried out for 6 hours. After completion of the reaction, the reaction mixture was poured into 500 ml of water, adjusted the pH to 1 to 2 with 4N hydrochloric acid and then 200 ml of toluene were added to effect extraction and separation. The resulting organic phase was washed with water, 5% aqueous sodium hydrogen carbonate and water in this order and finally dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure to obtain 35.5 g (yield : 99%) of 2-{4-(1-acetoxyethyl)phenyl)-5-decyloxypyrimidine. 31.9 g (0.08 mole) of the above 2-(4-(1-acetoxyethyl)phenyl)-5-decyloxypyrimidine were suspended in 450 ml of a 0.3 M phosphate buffer (pH 7.0) and 10 ml of chloroform and 1.6 g of lipase ([Amano P]) were added thereto, followed by vigorous stirring at 38 ± 2°C for 24 hours. After completion of the reaction, to the reaction mixture were added 300 ml of ethyl acetate to effect separation of the solution. Then, the organic phase was washed with water and concentrated under reduced pressure and the resulting residue was separated by silica gel column chromatography (eluent ; toluene : ethyl acetate). 13.9 g (yield : 48.7%) of (+)-2-{4-(1-hydroxyethyl)phenyl)-5-decyloxypyrimidine, [α] 20 / D = +26.0° (C=1, CHCl 3 ) and 16.1 g (yield: 50.5%) of (-)-2-{4-(1-acetoxyethyl)phenyl}-5-decyloxypyrimidine were obtained. Example 1 Into 20 ml of anhydrous dlmethylformamide were dissolved 1.78 g (5 millimole) of the (+)-2-{4-(1-hydroxyethyl)phenyl}-5-decyloxypyrimidine obtained in the Preparation Example (starting material compound (VI)] above, and then 0.24 g (6 millimoles) of 60% sodium hydride was added thereto, followed by stirring at 40°C for 1 hour. Subsequently, 1.79 g (7 millimole) of hexyl p-toluenesulfonate were added thereto, to subject to reaction at the same temperature for 2 hours. After completion of the reaction, the reaction mixture was poured into 200 ml of water, extracted with 200 ml of toluene, followed by separation thereof, and the organic phase was washed with water sufficiently, followed by drying over anhydrous magnesium sulfate. After the solvent was distilled off under reduced pressure, the resulting residue was purified by silica gel column chromatography (eluent; toluene : ethyl acetate) to obtain 1.81 g (yield : 82%) of (+)-2-{4-(1-hexyloxyethyl)phenyl}-5-decyloxypyrimidine. The physical values are shown in Table 1. Examples 2 and 3 Reaction and post-treatment were carried out in the same manner as in Example 1 except that (+)-2-{4-(1-hydroxyethyl)phenyl}-5-decyloxypyrimidine obtained in the Preparation Example (starting material compound (VI)] was used and the reagents as shown in Table-1 as the alkylating agents (IX), to obtain the results as shown in Table-1. Examples 4 and 5 Into 100 ml of methanol and 50 ml of tetrahydrofuran were dissolved 15 g of the (-)-2-{4-(1-acetoxyethyl)phenyl}-5-decyloxypyrimidine obtained in the Preparation Example [starting material compound (VI)] above, and then 50 ml of 20% aqueous sodium hydroxide solution were added thereto, to subject to reaction at 40 to 45°C for 4 hours. After completion of the reaction, 4N hydrochloric acid was added to the reaction mixture to adjust it to pH 7 to 8, and then 200 ml of toluene were added to effect extraction and separation. After the organic phase was washed with water, the solvent was distilled off under reduced pressure to obtain 13.2 g (yield : 98.5%) of (-)-2-{4-(1-hydroxyethyl)phenyl}-5-decyloxypyrimidine. Reaction and post-treatment were carried out in the same manner as in Example 1 except that 1.78 g (5 millimoles) of the (-)-2-{4-(1-hydroxyethyl)phenyl}-5-decyloxypyrimidine obtained above were used and the reagents as shown in Table-1 were used as the alkylatingagent to obtain the results as shown in Table-1. Examples 6 to 11 Reaction and post-treatment were carried out in the same manner as in Example 1, except that the optically active aromatic alcohols (VI) were used as the starting-material and the reagents as shown in Table-1 were used to obtain the results as shown in Table-1. Example 12 The liquid crystal composition as shown in Table 2 was formulated by using optically active benzene derivative (I). Formulation was carried out by weighing predetermined amounts of predetermined compounds and mixing them in a sample bottle under heating and melting. [Preparation Method of Liquid Crystal Element] On a glass substrate Provided with indium oxide transparent electrodes was provided a polyimide type polymer coating film, followed by rubbing in a predetermined direction by use of gauzes. A liquid crystal cell was assembled by employing glass fibers (diameter : 5 µm) as a spacer so as to maintain the rubbing directions of two pieces of the substrate paralleled and the liquid crystal composition (or liquid crystal compound) described above was charged thereinto and sealed under vacuum to obtain a liquid crystal element. The liquid crystal element was combined with a polarizer and 20 V was applied to the electric field to observe and measure changes in intensity of transmitted light. As a result, it has been confirmed that the liquid crystal element is capable of functioning as a switching element. It has been found that, as is apparent from these results, when the optically active benzene derivatives (I-d) of the present invention are used as a liquid crystal material, lowering of the temperature range for the Sc* phase can be performed as compared with the Comparative example, and further a liquid crystal composition having a spontaneous polarlzation value enough to practical use can be obtained.

Claims: An optically active benzene derivative represented by the formula (I): wherein: R 1 represents an alkyl group having 3 to 20 carbon atoms; Y represents -O-, -COO- or -OCO-; m represents an integer of 0 or 1; R 2 represents an alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms; Ar represents or Z represents wherein t represents a number of 0 to 5; and * indicates an asymmetric carbon atom. An optically active benzene derivative according to Claim 1, wherein R 2 represents an alkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms. An optically active benzene derivative according to Claim 1, wherein R 2 is an optically active group. A process for preparing an optically active benzene derivative of formula (I-d) wherein: R 1 represents an alkyl group having 3 to 20 carbon atoms; R 2 represents an alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by chalogen atoms; Y represents -O-, -COO- or -OCO-; m represents a number of 0 or 1; Z" represents wherein t represents a number of 0 to 5; Ar" represents and * indicates an asymmetric carbon atom; which process comprises reacting an optically active aromatic alcohol represented by the formula (VI): (wherein R 1 , Y, Ar", Z" and m are as defined above) with an alkylating reagent represented by the formula (IX) : Q-R 2 wherein R 2 is as defined above; and Q represents a halogen atom or a group of formula -OSO 2 R"' wherein R"' represents a lower alkyl group or a phenyl group optionally substituted by alkyl groups. The process according to Claim 4, wherein the reaction is carried out in the presence of a basic substance. A liquid crystal composition having at least two components at least one of which is an optically active benzene derivative represented by the formula (I) wherein: R 1 represents an alkyl group having 3 to 20 carbon atoms; Y represents -O-, -COO- or -OCO-; m represents an integer of 0 or 1; R 2 represents an alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms; Ar represents or Z represents wherein t represents a number of 0 to 5; and * indicates an asymmetric carbon atom. A light switching element employing a liquid crystal composition according to Claim 6 as a liquid crystal material.

Inventors: FUJISAWA KOICHI, HIGASHII TAKAYUKI, KAWAKAMI CHIZU, KURIMOTO ISAO, MINAI MASAYOSHI, TANI TAKESHI, TODA SHOJI, FUJISAWA, KOICHI, HIGASHII, TAKAYUKI, KAWAKAMI, CHIZU, KURIMOTO, ISAO, MINAI, MASAYOSHI, TANI, TAKESHI, TODA, SHOJI
Applicants: SUMITOMO CHEMICAL CO, SUMITOMO CHEMICAL COMPANY LIMITED
Application year: 1989
Main classification: C07D239
IPC codes: C09K19, C07C69, C07C49, C07C45, C07C43, C07D239, C07C65