SQUARILIUM COMPOUND AND LIQUID CRYSTAL COMPOSITION CONTAINING THE SAME

Abstract: A squarilium compound represented by the following for­ ula (I) and a liquid crystal composition containing the same are discosed: wherein X and Y each represents wherein R¹ represents a hydrogen atom, an alkyl group, a sub­ stituted or unsibstituted aryl group or a substituted or unsub­ stituted aralkyl group; R², R³ and R⁴ each represents a hydro­ gen atom, an alkyl group or a substituted or unsubstituted alkoxy group; R⁵ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group; ring A represents a cyclic alky­ lene; ring B represents a substituted or unsubstituted aromatic ring; and ring C represents a heterocyclic ring containing one or two of a nitrogen atom, an oxygen atom and a sulfur atom; with proviso that X and Y are not the same when either one of them represents and a liquid crystal composition containing the squarilium com­ pound of the formula (I). The squarilium compound (I) are soluble in a wide variety of solvents and resistant to light, and their maximum absorp­ tion wavelengths in these solvent are in the ranges of from 700 to 900 nm.

Description: This invention relates to a squarilium compound and a liquid crystal composition containing the same. BACKGROUND OF THE INVENTION An information recording system using laser beams has recently been studied, wherein a liquid crystal having dissolved therein a compound which absorbs a laser beam of specific wavelengths is heated by irradiation of such a laser beam, whereupon the state of the irradiated portion is changed, for example, from an isotropically aligned state to a scattered state, as described, e.g., in IBM Tech. Discl. Bull ., 21 , 2007 (1978). On the other hand, it is known that a squarilium compound has photoconductivity and can be used, e.g., as an electric charge generator for electrophotographic light-sensitive materials (Japanese Patent Application (OPI) No. 105536/74, the term "OPI" as herein used referring to "published unexamined application"), a laser beam-absorbing material for laser recording liquid crystal display devices (Japanese Patent Application (OPI) No. 197485/84) and as a recording material for photodiscs (Japanese Patent Application (OPI) Nos. 46221/81, 217758/83 and 129954/84). However, conventionally known squarilium compounds involve problems of solubility such that they are soluble only in limited solvents, such as aprotic polar solvents, e.g., N,N-dimethylformamide, N-methylpyrolidone, N ,N-dimethylacetamide, formamide, dimethyl sulfoxide, etc., and also some of them have very poor solubility as in the case of Compound No. 6 disclosed in Japanese Patent Application (OPI) No. 129954/84. Further, many of these known compounds not only have the maximum absorption wavelengths in their solutions far aside from the oscillation wavelengths of semiconductor lasers, i.e., 780 nm, 830 nm or 850 nm but also lack in stability due to their insufficient light-resistance. Reference GB-A-2 140 023 discloses the use of the squarilium compound in a liquid crystal display device where video images are written into the cell comprising the liquid crystal material and the squarilium dye. The purpose of the dye is to improve the rate of transfer of heat from the laser to the liquid crystal material. These squarilium compounds suffer from problems of solubility (being soluble only in limited solvents) and furthermore also have the maximum absorption wave-length in solutions in which they are soluble far aside from the oscillation wave-lengths of semiconductor lasers used in information recording materials (850 nm, 830 nm or 780 nm). Also they lack stability due to their insufficient light-resistance. In contrast the squarilium compounds of the invention have better than expected light resistance. Also they show excellent sensitivity to a 830 nm laser beam. The conventional squarilium compounds can, therefore, find only limited applications and are not satisfactorily applicable to various information recording materials, particularly those using a laser beam as a light source. SUMMARY OF THE INVENTION Accordingly, an object of this invention is to provide a novel squarilium compound which can eliminate the above-described problems associated with the known squarilium compounds, as well as a liquid crystal composition containing such a novel squarilium compound. That is, the present invention relates to a squarilium compound represented by the formula (I): wherein X represents Y represents wherein R¹ represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group; R², R³ and R⁴ each represents a hydrogen atom, an alkyl group or a substituted or unsubstituted alkoxy group; R⁵ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group; ring A represents a cyclic alkylene; ring B represents a substituted or unsubstituted aromatic ring; and ring C reprsents a heterocyclic ring containing one or two of a nitrogen atom, an oxygen atom and a sulfur atom; with proviso that X and Y are not the same when either one of them represents and a liquid crystal composition containing the squarilium compound of the formula (I). DETAILED DESCRIPTION OF THE INVENTION The compound represented by the formula (I) according to the present invention can easily be prepared by, for example, reacting an azulene derivative represented by the formula (II) or (III): X - H (II) Y - H (III) wherein X and Y are as defined above, with 3,4-dihydroxy-3-cyclobutene-1,2-dione, i.e., squaric acid, represented by the formula: in a solvent. The solvent which can be used in the above reaction includes alcohols, e.g., methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol, 2-butanol, amyl alcohol, 1-hexanol, cyclohexanol, 1-heptanol, 1-nonanol, etc.; and mixed solvents of these alcohols and aromatic hydrocarbons, e.g., benzene, toluene, xylene, chlorobenzene, etc. The reaction temperature is selected from 70 to 150°C, and preferably from 90 to 120°C. The starting compound represented by the formula (II) or (III) includes the azulene derivatives as follows: (a) The position numbering system of the following benz[a]azulene derivatives is 1 , 2,3, 4-Tetrahydro-3-methyl-benz[a]azulene 1,2,3,4-Tetrahydro-3-t-butyl-benz[a]azulene 7-Isopropyl-benz[a]azulene 8-Isopropyl-benz[a]azulene 3-Ethyl-8-isopropyl-benz[a]azulne 3-t-Butyl-benz[a]azulene 3-t-Butyl-8-isopropyl-benz[a]azulene 3-n-Pentyl-8-isopropyl-benz[a]azulene 3-n-Heptyl-7-methyl-benz[a]azulene 3-n-Heptyl-8-isopropyl-benz[a]azulene 3-n-Octyl-8-isopropyl-benz[a]azulene 2-Methoxy-8-isopropyl-benz[a]azulene 2-n-Butoxy-8-methyl-benz[a]azulene 3-Methoxy-7-isopropyl-benz[a]azulene 3-Methoxy-8-isopropyl-benz[a]azulene 3-Bromo-8-isopropyl-benz[a]azulene 3-Ethyl-5-methoxy-8-isopropyl-benz[a]azulene 3-n-Butyl-5-methoxy-8-isopropyl-benz[a]azulene 3-n-Propyl-5-butoxy-7-isopropyl-benz[a]azulene 5-Ethoxyethoxy-8-isopropyl-benz[a]azulene 3-Ethyl-7-isopropyl-benz[a]azulene 3-n-Propyl-7-isopropyl-benz[a]azulene 3-n-Propyl-8-isopropyl-benz[a]azulene 3-n-Butyl-8-isopropyl-benz[a]azulene 3-n-Hexyl-7-isopropyl-benz[a]azulene 3-n-Heptyl-8-methyl-benz[a]azulene 3-n-Octyl-8-methyl-benz[a]azulene 3-n-Tridecyl-8-methyl-benz[a]azulene 2-n-Butoxy-8-isopropyl-benz[a]azulene 2-n-Heptyloxy-8-isopropyl-benz[a]azulene 3-Methoxy-8-isopropyl-benz[a]azulene 3-t-Butyl-5-methoxy-8-isopropyl-benz[a]azulene 3-Ethyl-5-n-butoxy-8-isopropyl-benz[a]azulene 3-n-Propyl-5-n-octyloxy-7-isopropyl-benz[a]azulene 5-n-Tridecyloxy-8-isopropyl-benz[a]azulene 2-Methoxyethoxy-8-isopropyl-benz[a]azulene 2-Ethoxyethoxyethoxy-8-isopropyl-benz[a]azulene 5-Methoxyethoxyethoxy-8-isopropyl-benz[a]azulene 3-n-Pentyl-benz[a]azulene 3-n-Heptyl-benz[a]azulene 3-n-Propyl-benz[a]azulene 3-t-Butyl-8-isopropyl-benz[a]azulene 7-Isopropyl-benz[a]azulene 3-n-Hexyl-benz[a]azulene 3-n-Octyl-8-isopropyl-benz[a]azulene 3-n-Pentyl-7-isopropyl-benz[a]azulene 3-n-Butyl-7-isopropyl-benz[a]azulene (b) The position numbering system of the following azuleno[1,2-b]thiophene derivatives is Azuleno[1,2-b] thiophene 7-Methylazuleno[1,2-b]thiophene 7-Isopropylazuleno[1,2-b]thiophene 6-Methylazuleno[1,2-b]thiophene 6-Isopropylazuleno[1,2-b]thiophene 4-Methoxy-7-isopropylazuleno[1,2-b]thiophene 4-Butoxy-7-isopropylazuleno[1,2-b]thiophene 4-Octyloxy-6-isopropylazuleno[1,2-b]thiophene 4-Ethoxyethoxy-7-isopropylazuleno[1,2-b]thiophene 4-Methoxyethoxyethoxy-7-isopropylazuleno[1,2-b]thiophene 1,4,8-Trimethylazuleno[1,2-b]thiophene 4-Tridecyloxy-7-isopropylazuleno[1,2-b]thiophene 4-Octadecyloxy-7-isopropylazuleno[1,2-b]thiophene Azuleno[1,2-b]1,2-dihydroxythiophene 7-Isopropylazuleno[1,2-b]1,2-dihydrothiophene 6-Isoprpopylazuleno[1,2-]1,2-dihydrothiophene 7-Methylazuleno[1,2-b]1,2-dihydrothiophene 4-Methoxy-7-isopropylazuleno[1,2-b]1,2-dihydrothiophene 4-Hepthyloxy-7-isopropylazuleno[1,2-b]1,2-dihydrothiophene 4-Octadecyloxy-7-isopropylazuleno[1,2-b]1,2-dihydrothiophene 4-Methoxy-6-isopropylazuleno[1,2-b]1,2-dihydrothiophene 4-Methoxyazuleno[1,2-b]1,2-dihydrothiophene 2-Methyl-7-isopropylazuleno[1,2-b]thiophene 4-Methoxyethoxy-7-isopropylazuleno[1,2-b]1,2-dihydrothiophene 2-Methylazuleno[1,2-b]thiophene 4-Methoxyazuleno[1,2-b]thiophene 1,2-Diphenylazuleno[1,2-b]thiophene 4,6,8-Trimethyl-2-phenylazuleno[1,2-b]thiophene (c) The position numbering system of the following azuleno[2,1-b]thiophene derivatives is Azuleno[2,1-b]thiophene 7-Methylazuleno[2,1-b]thiophene 7-Isopropylazuleno[2,1-b]thiophene 6-Methylazuleno[2,1-b]thiophene 6-Isopropylazuleno[2,1-b]thiophene 4-Methoxy-7-isopropylazuleno[2,1-b]thiophene 4-Butoxy-7-isopropylazuleno[2,1-b]thiophene 4-Octyloxy-6-isopropylazuleno[2,1-b]thiophene 4-Ethoxyethoxy-7-isopropylazuleno[2,1-b]thiophene 4-Methoxyethoxyethoxy-7-isopropylazuleno[2,1-b]thiophene 4-Dodecyloxy-7-isopropylazuleno[2,1-b]thiophene 4-Octadecyloxy-7-isopropylazuleno[2,1-b]thiophene Azuleno[2,1-b]2,3-dihydrothiophene 7-Isopropylazuleno[2,1-b]2,3-dihydrothiophene 6-Isopropylazuleno[2,1-b]2,3-dihydrothiophene 7-Methylazuleno[2,1-b]2,3-dihydrothiophene 4-Methoxy-7-isopropylazuleno[2,1-b]2,3-dihydrothiophene 4-Heptyloxy-7-isopropylazuleno[2,1-b]2,3-dihydrothiophene 4-Octadecyloxy-7-isopropylazuleno[2,1-b]2,3-dihydrothiophene 4-Methoxy-6-isopropylazuleno[2,1-b]2,3-dihydrothiophene 4-Methoxyazuleno[2,1-b]2,3-dihydrothiophene 2-Ethoxycarbonylazuleno[2,1-b]thiophene 3-Methylazuleno[2,1-b]thiophene 3-Methoxyazuleno[2,1-b]thiophene 4-Methoxyethoxy-7-isopropylazuleno[2,1-b]2,3-dihydrothiophene 4-Methoxyazuleno[2,1-b]thiophene (d) The position numbering system of the following azuleno[1,2-c]thiophene derivatives is Azuleno[1,2-c]thiophene 7-Methylazuleno[1,2-c]thiophene 7-Isopropylazuleno[1,2-c]thiophene 6-Methylazuleno[1,2-c]thiophene 6-Isopropylazuleno[1,2-c]thiophene 4-Methoxy-7-isopropylazuleno[1,2-c]thiophene 4-Butoxy-7-isopropylazuleno[1,2-c]thiophene 4-Octyloxy-6-isopropylazuleno[1,2-c]thiophene 4-Ethoxyethoxy-isopropylazuleno[1,2-c]thiophene 4-Methoxyethoxyethoxy-7-isopropylazuleno[1,2-c]thiophene 4-Octadecyloxy-7-isopropylazuleno[1,2-c]thiophene Azuleno[1,2-c]1,3-dihydrothiophene 7-Isopropylazuleno[1,2-c]1,3-dihydroxythiophene 6-Isopropylazuleno[1,2-c]1,3-dihydrothiophene 7-Methylazuleno[1,2-c]1,3-dihydrothiophene 4-Methoxy-7-isopropylazuleno[1,2-c]1,3-dihydrothiophene 4-Heptyloxy-7-isopropylazuleno[1,2-c]1,3-dihydrothiophene 4-Octadecyloxy-7-isopropylazuleno[1,2-c]1,3-dihydrothiophene 4-Methoxy-6-isopropylazuleno[1,2-c]1,3-dihydrothiophene 4-Methoxyazuleno[1,2-c]1,3-dihydrothiophene 4-Methoxyethoxy-7-isopropylazuleno[1,2-c]1,3-dihydrothiophene 4-Methoxyazuleno[1,2-c]thiophene (e) The position numbering system of the following azuleno[1,2-b]furan derivatives is Azuleno[1,2-b]furan derivatives is 7-Methylazuleno[1,2-b]furan 7-Isopropylazuleno[1,2-b]furan 6-Methylazuleno[1,2-b]furan 6-Isopropylazuleno[1,2-b]furan 4-Methoxy-7-isopropylazuleno[1,2-b]furan 4-Butoxy-7-isopropylazuleno[1,2-b]furan 4-Octyloxy-6-isopropylazuleno[1,2-b]furan 4-Ethoxyethoxy-7-isopropylazuleno[1,2-b]furan 4-Methoxyethoxyethoxy-7-isopropylazuleno[1,2-b]furan 4-Octadecyloxy-7-isopropylazuleno[1,2-b]furan 4-Methoxyazuleno[1,2-b]furan (f) The Position numbering system of the following azuleno[1,2-b]pyrrole derivatives is Azuleno[1,2-b]pyrrole 7-Methylazuleno[1,2-b]pyrrole 7-Isopropyl[1,2-b]pyrrole 6-Isopropyl[1,2-b]pyrrole 3-Ethoxycarbonylazuleno[1,2-b]pyrrole 3-Ethoxycarbonyl-7-isopropylazuleno[1,2-b]pyrrole 3-Ethoxycarbonyl-6-isopropylazuleno[1,2-b]pyrrole (g) The position numbering system of the following azuleno[1,2-c]pyridine derivatives is Azuleno[1,2-c]pyridine 8-Methylazuleno[1,2-c]pyridine 8-Isopropylazuleno[1,2-c]pyridine 7-Isopropylazuleno[1,2-c]pyridine 3-Ethoxycarbonylazuleno[1,2-c]1,2,3,4-tetrahydropyridine 3-Ethoxycarbonyl-8-isopropylazuleno[1,2-c]1,2,3,4-tetrahydropyridine 3-Ethoxycarbonyl-7-isopropylazuleno[1,2-c]1,2,3,4-tetrahydropyridine (h) The position numbering system of the following azuleno[2,1-c]pyridine derivatives is Azuleno[2,1-c]pyridine Methylazuleno[2,1-c]pyridine 8-Isopropylazuleno[2,1-c]pyridine 7-Isopropylazuleno[2,1-c]pyridine Azuleno[2,1-c]1,2,3,4-tetrahydropyridine Azuleno[2,1-c]3,4-dihydropyridine 2-Ethoxycarbonylazuleno[2,1-c]1,2,3,4-tetrahydropyridine 2-Ethoxycarbonyl-8-isopropylazuleno[2,1-c]1,2,3,4-tetrahydropyridine 2-Ethoxycarbonyl-7-isopropylazuleno[2,1-c]1,2,3,4-tetrahydropyridine (i) The position numbering system of the following azuleno[1,2-b]pyridine derivatives is Azuleno[1,2-b]pyridine 4-Ethoxycarbonylazuleno[1,2-b]1,2,3,4-tetrahydropyridine 4-Ethoxycarbonyl-8-isopropylazuleno[1,2-b]1,2,3,4-tetrahydropyridine 4-Ethoxycarbonyl-7-isopropylazuleno[1,2-b]1,2,3,4-tetrahydropyridine (j) The position numbering system of the following azuleno[2,1-b]pyridine derivatives is Azuleno[2,1-b]pyridine 2,3-Dichloroazuleno[2,1-b]pyridine 2-Methoxy-3-ethoxycarbonylazuleno[2,1-b]pyridine 2-Methylamino-3-ethoxycarbonylazuleno[2,1-b]pyridine 2-Methoxy-3-cyanoazuleno[2,1-b]pyridine Among the squarilium compounds represented by the formula (I), the squarilium compounds represented by the following formulae (IV) to (XIII) are preferred. wherein R¹⁰ represents a hydrogen atom or alkyl group having from 1-13 carbon atoms; R¹³ represents a hydrogen atom or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms; and R¹⁴ represents a hydrogen atom, a halogen atom, an alkyl group having from 1 to 13 carbon atoms or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms; with proviso that at least one of R¹⁰, R¹³ and R¹⁴ represents an alkyl group having from 1 to 13 carbon atoms or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms. wherein R⁶ represents a hydrogen atom or an alkyl group having from 1 to 13 carbon atoms; R²², R 22' , R²³, R 23' , each represents a hydrogen atom, an alkyl group having from 1 to 13 carbon atoms or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms; R²⁴ represents a hydrogen atom or alkyl group having from 1 to 13 carbon atoms; with proviso that at least one of the symmetrical pairs of R²² and R 22' ; R²³ and R 23' comprises different groups and ring B is as defined above. wherein R²² R 22' , R²³, R 23' , ring A and ring B are as defined above. wherein R²², R 22' , R²³, R 23' , and ring B are as defined above; and ring B' has the same meanings as ring B. wherein R², R³ and ring B are as defined above and R²⁶, R²⁷ and R²⁸ each represents an alkyl group. wherein R², R³ and ring C are as defined above; R 2' has the same meanings as R²; R 3' has the same meanings as R 3' ; and ring C' has the same meanings as ring C. wherein R², R³, R 2' , R 3' and ring C are as defined above; R 1' has the same meaning as R¹; R 4' has the same meaning as R⁴; and R 5' has the same meaning as R⁵. wherein R², R³, R 2' , R 3' , R 4' , ring A and ring C are as defined above. wherein R², R³, R 2' , R 3' , R 4' , ring B and ring C are as defined above. wherein R², R³, R 2' , R 3' , and ring B are as defined above; and R³⁸ and R³⁹ represent a hydrogen atom or an alkyl group having from 14 to 25 carbon atoms with proviso that at least one of R³⁸ and R³⁹ represents an alkyl group having from 14 to 25 carbon atoms. In the above-described formulae (I) to (XIII), substituents for the substituted alkoxy group are an alkoxy group, an alkoxyalkoxy group, an alkoxyalkoxyalkoxy group. The substituted aralkyl group is a benzyl or phenylethyl group substituted with a fluorine atom, a chlorine atom, a bromine atom,an alkyl group or an alkoxy group. The substituted aryl group is a phenyl group substituted with the same substituents as enumerated for the substituted aralkyl group. The heterocyclic ring as represented by rings C or C' is a furan ring, a dihydrofuran ring, a thiophene ring, a dihydrothiophene ring, a pyrrole ring, a dihydropyrrole ring, a pyrazole ring, an imidazole ring, a thiazole ring, a pyridine ring, a dihydropyridine ring, a tetrahydropyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a thiapyran ring, a quinoxaline ring, The compounds (I) of the present invention are soluble in halogen-containing hydrocarbon solvents, e.g., chloroform, dichloromethane, dichloroethane, etc.; ether solvents, e.g., diethyl ether, dioxane, tetrahydrofuran, dimethoxyethane, etc.; ester solvents, e.g., ethyl acetate, etc.; aromatic hydrocarbon solvents, e.g., benzene, toluene, xylene, chlorobenzenes, etc.; amide solvents, e.g., acetamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.; alcohol solvents, e.g., methanol, ethanol, methyl cellosolve, etc.; dimethyl sulfoxide; and the like. They also exhibit satisfactory light-resistance. In addition to the solubility in a wide variety of solvents and good light-resistance as described above, the compounds of the present invention possess a remarkable industrial value in that the maximum absorption wavelengths in the above-recited solvents fall within a range of from 700 to 900 nm and, in particular, are centered mainly in the vicinity of 780 nm, 830 nm or 850 nm that is an oscillation wavelength of a semiconductor laser. Therefore, they are expected to be useful in the field of various information materials utilizing a laser beam, such as laser beam-absorbing materials for laser recording liquid crystal display devices, electrophotographic light-sensitive materials of electrophotographic printers using a laser beam as a light source, recording materials for photodiscs in which an information can be recorded and read-out by a laser beam, infrared-cut filters, and the like. The squarilium compounds of the present invention can also be employed in liquid crystal compositions in combination with liquid crystals for the above-described liquid crystal display devices in which an information is recorded by a laser beam. The liquid crystals which can be used in combination with the squarilium compounds of this invention include smectic liquid crystals and cholesteric liquid crystals. Examples of the smectic liquid crystals are biphenyl type liquid crystals, terphenyl type liquid crystals, cyclohexylcyclohexane type liquid crystals, biphenylcyclohexane type liquid crystals, cyclohexylbiphenylcyclohexane type liquid crystals, phenylcyclohexyl carboxylate type liquid crystals, cyclohexylcyclohexyl benzoate type liquid crystals, cyclohexylphenylcyclohexyl carboxylate type liquid crystals, cyclohexylcyclohexylcyclohexyl carboxylate type liquid crystals, pyrimidine type liquid crystals, etc. and mixtures thereof. Cholesteric liquid crystals can be obtained by adding an optically active substance to nematic liquid crystals of, for example, cyclohexylcyclohexane type liquid crystals, phenylcyclohexane type liquid crystals, biphenyl type liquid crystals, terphenyl type liquid crystals, phenylcyclohexyl carboxylate type liquid crystals, phenyl benzoate type liquid crystals, etc. The optically active substance to be used includes chiralnematic compounds wherein an optically active group, e.g., a 2-methylbutyl group, a 3-methylbutoxy group, a 3-methylpentyl group, a 3-methylpentoxy group, a 4-methylhexyl group, a 4-methylhextoxy group, etc., is introduced to a nematic liquid crystals. Additional examples of the optically active substance include derivatives of alcohols, e.g., ℓ-menthol, d-borneol, etc.; derivatives of d-camphor, 3-methylcyclohexane, etc.; derivatives of carboxylic acids, e.g., d-citronellic acid, ℓ-camphoric acid, etc.; derivatives of aldehydes, e.g., d-citronellal, etc.; derivatives of alkenes, e.g., d-linonene, etc.; derivatives of amines, amides or nitriles; and the like. The liquid crystal compositions in accordance with the present invention can contain known dichromic dyes and additives, such as viscosity reducing agent. The present invention will now be illustrated in greater detail with reference to the following examples, but it should be understood that these examples are not limiting the present invention. EXAMPLE 1 To 0.038 g of 3,4-dihydroxy-3-cyclobutene-1,2-dione was added 20 ml of n-butyl alcohol, and the mixture was heated to about 100°C to form a solution. To the solution were added 0.15 g of 8-isopropyl-benz[a]azulene and 15 ml of benzene, and the mixture was stired at 95 to 105°C for about 1 hour while azeotropically removing the produced water. After cooling, n-hexane was added to the reaction mixture, and the precipitated crystals were purified by column chromatography to obtain 0.16 g of a compound of the formula: This compound had a melting point of 194 to 195°C, and its absorption spectrum in a chloroform solution showed the maximum absorption at 823 nm. EXAMPLE 2 In the same manner as described in Example 1 except for replacing the 8-isopropyl-benz[a]azulene as used in Example 1 with the equimolar amount of 3-ethyl-8-isopropyl-benz[a]azulene, a compound of the formula: was obtained. This compound had a melting point of 195 to 196°C, and its absorption spectrum in a chloroform solution had the maximum absorption wavelength at 836 nm. EXAMPLE 3 In the same manner as described in Example 1 except for replacing the 8-isopropyl-benz[a]azulene as used in Example 1 with the equimolar amount of 3-t-butyl-benz[a]azulene and recrystallizing the crude crystals from n-butanol, a compound of the formula: was obtained. This compound had a melting point of 310 to 311°C, and its absorption spectrum in a chloroform solution showed the maximum absorption wavelength of 823 nm. EXAMPLES 4 TO 30 In the same manner as described in Example 1, 27 squarilium compounds as shown in Table 1 below were prepared. Structures and maximum absorption wavelengths in chloroform solutions of these compounds are also shown in Table 1. EXAMPLE 31 To 0.11 g of 3,4-dihydroxy-3-cyclobutene-1,2-dione was added 30 ml of n-butyl alcohol, and the mixture was heated to about 100°C to form a solution. To this solution were added 0.20 g of 1-methyl-4-methyl-7-isopropylazulene, 0.23g of 8-isopropylbenz(a)azulene and 20 ml of benzene, and the resulting solution was stirred at 95 to 105°C for about 1 hour while azeotropically removing the produced water. After cooling, the reaction mixture was subjected to column chromatography to obtain a compound of the following formula This compound had a melting point of 129.0 to 130.0°C, and the maximum absorption wavelength of its absorption spectrum in a chloroform solution was 796 nm. EXAMPLES 32 TO 71 In the same manner as described in Example 31, squarilium compounds as shown in Tables 2 to 4 were prepared. Structures and maximum absorption wavelengths in chloroform solutions of these compounds are also shown in Tables 2 to 4 below. EXAMPLE 72 To 0.11 g of 3,4-dihydroxy-3-cyclobutene-1,2-dione was added 30 ml of n-butyl alcohol, and the mixture was heated to about 100°C to form a solution. To the solution were added 0.20 g of 1,4-dimethyl-7-isopropylazulene, 0.17 g of 4,6,8-trimethylazulene and 20 ml of toluene, and the mixture was stirred at 105 to 110°C for about 1 hour while azeotropically removing the produced water. After cooling, the reaction mixture was purified by column chromatography to obtain squarilium compounds shown in Table 5 below. EXAMPLE 80 Ten milliliters of n-butyl alcohol was added to 37 mg of 3,4-dihydroxy-3-cyclobutene-1,2-dione, and the mixture was heated to about 100°C to form a solution. To the solution were added 120 mg of azuleno[1,2-b]thiophene and 15 ml of toluene, and the mixture was stirred at 105 to 110°C for about 20 minutes while azeotropically removing the produced water. After cooling, the reaction mixture was purified by column chromatography to obtain a compound of the formula: This compound was not melted below 300°C, and its absorption spectrum in the chloroform solution showed the maximum absorption at 775 nm. EXAMPLE 81 In the same manner as described in Example 80 but replacing the azuleno[1,2-b]thiophene as used in Example 80 with the equimolar amount of 7-isopropylazuleno[1,2-b]thiophene, a compound of the following formula was obtained: This compound had a melting point of 224.5 to 226.0°C and the maximum absorption wavelength in its chloroform solution was 783 nm. EXAMPLE 82 In the same manner as described in Example 80 but replacing the azuleno[1,2-b]thiophene as used in Example 80 with the equimolar amount of 7-isopropylazuleno[1,2-b]1,2-dihydrothiophene, a compound of the following formula was obtained: This compound had a melting point of 219.0 to 220.5°C and its absorption spectrum in a chloroform solution showed the maximum absorption at 815 nm. EXAMPLE 83 In the same manner as in Example 80 except for replacing the azuleno[1,2-b]thiophene as used in Example 80 with the equimolar amount of 7-isopropylazuleno[1,2-c]-1,3-dihydrothiophene, a compound of the following formula was obtained: This compound had a melting point of 249.5 to 250.5°c and its absorption spectrum in the chloroform solution showed the maximum absorption at 746 nm. EXAMPLE 84 In the same manner as described in Example 80 but replacing the azuleno[1,2-b]thiophene with the equimolar amount of 7-isopropylazuleno[2,1-b]2,3-dihydrothiophene, a compound of the following formula was obtained. This compound had a melting point of 220.0 to 221.5°C and its absorption spectrum in the chloroform solution showed the maximum absorption at 815 nm. EXAMPLE 85 In the same manner as in Example 80 except for replacing the azuleno[1,2-b]thiophene as used in Example 80 with the equimolar amount of 6-isopropylazuleno[1,2-b]1,2-dihydrothiophene, a compound of the following formula was obtained: This compound had a melting point of 254.5 to 255.0°C, and its absorption spectrum in the chloroform solution showed the maximum absorption at 804 nm. EXAMPLE 86 In the same manner as in Example 80 except for replacing the azuleno[1,2-b]thiophene as used in Example 80 with the equimolar amount of 7-isopropylazuleno[1,2-b]furan, a compound of the following formula was obtained: This compound was not melted below 300°C, and its absorption spectrum in the chloroform solution showed the maximum absorption at 760 nm. EXAMPLE 87 In the came manner as in Example 80 but replacing the azuleno[1,2-b]thiophene with the equimolar amount of 3-ethoxycarbonyl-8-isopropylazuleno-[1,2-c]1,2,3,4-tetrahydropyridine, a compound of the following formula was obtained: This compound had a melting point of 219 to 220°C, and its absorption spectrum in the chloroform solution showed the maximum absorption at 752 nm. EXAMPLES 88 TO 162 In the same manner as described in Example 80, squarilium compounds shown in Tables 6 to 9 were obtained. Their structures and the maximum absorption wavelengths in their chloroform solutions are shown in Tables 6 to 9. EXAMPLES 163 to 171 EXAMPLE 163 Thirty milliliters of n-butyl alcohol was added to 15 mg of 3,4-dihydroxy-3-cyclobutene-1,2-dione, and the mixture was heated to about 100°C to form a solution. To the solution were added 50 mg of 1-n-heptadecylazulene and 15 ml of toluene, and the mixture was stirred at 105 to 110°C for about 20 minutes while azeotropically removing the produced water. After cooling, the reaction mixture was purified by column chromatography to obtain squarilium compounds as shown in Table 10 below. Their structures and the maximum absorption wavelengths in chloroform are shown in Table 10.

Claims: A squarilium compound represented by the formula (I): wherein X represents Y represents wherein R¹ represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group; R², R³ and R⁴ each represents a hydrogen atom, an alkyl group or a substituted or unsubstituted alkoxy group; R⁵ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group; ring A represents a cyclic alkylene ; ring B represents a substituted or unsubstituted aromatic ring; and ring C represents a heterocyclic ring containing one or two of a nitrogen atom, an oxygen atom and a sulfur atom; with proviso that X and Y are not the same when either one of them represents A squarilium compound as in claim 1, wherein X represents wherein R⁶ represents a hydrogen atom or an alkyl group having from 1 to 13 carbon atoms; and R⁷ and R⁸ each represents a hydrogen atom, an alkyl group having from 1 to 13 carbon atoms or an alkoxy group having from 1 to 13 carbon atoms; with proviso that R⁷ and R⁸ are positioned at the 5-, 6- or 8-position, wherein R⁹ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group; and R¹⁰ represents a hydrogen atom or an alkyl group having from 1 to 13 carbon atoms, wherein R¹⁰ is as defined above; and R¹¹ and R¹² each represents an alkyl group having from 1 to 13 carbon atoms, wherein ring A is as defined in claim 1; and R¹⁰ is as defined above, or wherein R¹⁰ is as defined above; R¹³ represents a hydrogen atom or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms; and R¹⁴ represents a hydrogen atom, halogen atom, an alkyl group having from 1 to 13 carbon atoms or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms; with proviso that at least one of R¹⁰, R¹³ and R¹⁴ represents a group other than a hydrogen atom: A squarilium compound as in claims 2, wherein X represents wherein R⁶ , R⁷ and R⁸ are as defined in claim 2; with proviso that R⁷ and R⁸ is each positioned at the 5-, 6- or 8-position. A squarilium compound as in claim 3, wherein X represents wherein R¹¹ is as defined in claims 2; and R¹⁵ represents an alkyl group having from 1 to 13 carbon atoms; with proviso that R¹⁵ is positioned at the 5-, 6- or 8-position. A squalilim compound as in claim 2, wherein X and Y each represents wherein R¹⁰ R¹³ and R¹⁴ are as defined in claim 2; with proviso that at least one of R¹⁰ , R¹³ and R¹⁴ represents a group other than a hydrogen atom A squarilium compound as in claim 5, wherein X and Y each represents wherein R¹³ and R¹⁴ are as defined in claim 2; and R¹⁹ represents a hydrogen atom, a methyl group or an isopropyl group; with proviso that R¹³ is at the 5-position, and R¹⁹ is at the 7- or 8-position. A squarilium compound as in claims 6, wherein the compound is represented by the formula: A squarilium compound as in claim 6, wherein the compound is represented by the formula: A squarilium compound as in claims 6, wherein the compound is represented by the formula: A sauarilium compound as in claim 2, wherein the compound is represented by the formula: A squarilium compound as in claim 1, wherein X represents or wherein R¹, R², R³, R⁴, R⁵, ring A, ring B and ring C are as defined in claim 1; and Y represents wherein R2, R³ and ring C are as defined in claim 1. A squarilium compound as in claim 11, wherein X represents wherein R¹⁹ represents a hydrogen atom, a methyl group or an isopropyl group; R²² and R²³ each represents a hydrogen atom, an alkyl group having from 1 to 13 carbon atoms or a substituted or unsubstituted alkoxy group having from 1 to 13 carbon atoms; R²⁴ represents a hydrogen atom or an alkyl group having from 1 to 13 carbon atoms; and R³² represents a hydrogen atom, an alkyl group, a phenyl group, a benzyl group or with proviso that R¹⁹ is at the 5-, 6- or 7-position, and at least one of R¹⁹, R²² and R²³ represents a hydrogen atom, wherein R¹⁹ is as defined above. and ring A¹ represents a cyclic alkyline group having from 3 to 10 carbon atoms; with proviso that R¹⁹ is at the 5- or 6-position, or wherein R¹⁴ is as defined in claim 4; R¹⁹ is as above and R²² is as defined above; with proviso that R¹⁹ is at the 7-or 8-position. A squarilium compound as in claim 11, wherein X represents wherein R¹⁹ is as defined in claim 12; R²² and R²³ are as defined in claim 12; R³³ and R³⁴ each represents a hydrogen atom, a methyl group or a phenyl group; and R³⁵ represents a hydrogen atom or an alkoxycarbonyl group; with proviso that R¹⁹ is at the 6-or 7-position, and at least one of R¹⁹, R²² and R²³ represents a hydrogen atom, wherein R¹⁹ is as defined in claim 12; R³⁵ is as defined above; and R³⁶ and R³⁷ each represents a hydrogen atom, a halogen atom, an alkoxy group, an alkylamino group, an alkoxycarbonyl group or a cyano group; with proviso that R¹⁹ is at the 7- or 8-position. A squarilium compound as in claim 11, wherein Y represents wherein R¹⁹ is as defined in claim 12; R²² and R²³ are as defined in claim 12; R³³, R³⁴ and R³⁵ are as defined in claims 13; with proviso that R¹⁹ is at the 6- or 7-position, and at least one of R¹⁹ , R²² and R²³ represents a hydrogen atom, wherein R¹⁹ is as defined above; and R³⁵, R³⁶ and R³⁷ are as defined in claim 13; with proviso that R¹⁹ is at the 7- or 8-position. A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A squarilium compound as in claim 11, wherein the compound is represented by the formula: A liquid crystal composition containing a squarilium compound as claimed any one of claims 1 to 22.

Inventors: IWANAMI, JUNKO, MIURA, KANOE, OZAWA, TETSUO
Applicants: MITSUBISHI KASEI CORPORATION
Application year: 1985
Main classification: C07C49
IPC codes: C07D209, C07C49, C07C45, C07D409, C07D307, C09K19, C07D333, C07D221