JP5754116B2 - Amine compound, production method thereof, and use thereof - Google Patents

Description

  The present invention relates to a novel amine compound and an organic electroluminescence (EL) device using the same. The amine compound in the present invention can be used as a photosensitive material or an organic photoconductive material. Specifically, a hole transport material such as an organic EL device or an electrophotographic photosensitive member used for a flat light source or a display, or a hole injection material. And it is useful as a luminescent material. In particular, the amine compound of the present invention is very useful for an organic EL device using a phosphorescent material.

  Organic EL devices are currently being actively researched as next-generation thin flat displays, and have already been put into practical use in mobile phone displays and televisions. However, in order to further spread the organic EL element, it is required to further improve the light emission efficiency of the element.

  The general light emission mechanism of organic EL devices is that when electrons and holes are injected from both electrodes, they go to the counter electrode and recombine in the light emitting layer to generate excitons. Light emission occurs when the light returns to the ground state. In this excited state, there are a singlet excited state in which the direction of electron spin is antiparallel and a triplet excited state in which the direction of electron spin is parallel. Fluorescence emission involving only the excited state is the mainstream. However, from the simple quantum mechanical reasoning, the generation ratio of singlet excited state and triplet excited state generated by recombination of electrons and holes is 1: 3. Therefore, in the case of an organic EL element using fluorescence. The maximum value of the internal quantum efficiency is 25%. That is, 75% of the excited state is not used for light emission. In addition, since the light extraction efficiency to the outside of the organic EL element is about 20% at most, in the organic EL element using fluorescence, the external quantum efficiency is 25% × 20%, which is estimated to be about 5% at the maximum. .

  For this reason, in order to further improve the external quantum efficiency, it is necessary to use light emission from a triplet excited state that occupies 75% of the excited state, that is, phosphorescence. If this utilization becomes possible, the external quantum efficiency can be improved up to 20%. Against this background, in recent years, development of organic EL elements using phosphorescent materials has been activated.

  By the way, in an organic EL element using a phosphorescent material, a material used for a layer adjacent to the light emitting layer is required to have a higher triplet level (T1) than a fluorescent material. On the other hand, it is difficult to say that triplet levels of known materials conventionally used in organic EL elements using fluorescent materials are sufficient. For example, the triplet level of 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), which is well known as a hole transport material, is about 2.3 eV. Therefore, when combined with a phosphorescent material having a triplet level of 2.3 eV or higher, excitation energy cannot be sufficiently confined, resulting in a decrease in efficiency.

  Furthermore, in order to improve the triplet level, a method of introducing a skeleton such as a carbazole group into the material has been attempted. For example, a compound having a carbazole skeleton includes 4,4′-bis (N-carbazolyl) biphenyl (CBP) (see, for example, Non-Patent Document 1), but the triplet level is about 2.6 eV. It's hard to say that the level is sufficient.

R. Holms et. al. , Appl. Phys. Lett. 2003, 82, 2422.

  An object of the present invention is to provide an organic EL material that exhibits higher efficiency than conventional materials, particularly a material that is very useful in an organic EL element using a phosphorescent material. More specifically, it is to provide a novel material suitable for a hole injection material such as an organic EL element, a hole transport material and a light emitting material.

  As a result of intensive studies, the present inventors have found that the amine compound represented by the general formula (1) has a higher triplet level than a conventionally known material. That is, the present invention relates to an amine compound represented by the general formula (1) and its use.

（式中、環Ａ、環Ｂ及び環Ｃは各々独立してヘテロ原子を含んでもよい芳香環を表す。Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８及びＲ_９は各々独立して水素原子、炭素数１〜１８の直鎖、分岐若しくは環状のアルキル基、炭素数１〜１８の直鎖、分岐若しくは環状のアルコキシ基、炭素数６〜２４のアリール基、又は炭素数６〜２４のアリールオキシ基を表す。Ａｒ_１、Ａｒ_２、Ａｒ_３及びＡｒ_４は各々独立して炭素数６〜４０の置換基を有してもよいアリール基、又は炭素数５〜４０の置換基を有してもよいヘテロアリール基を表す。なお、Ｒ_３又はＲ_４とＲ_５又はＲ_６はお互いに結合して環を形成してもよい。また、Ａｒ_１とＡｒ_２、及びＡｒ_３とＡｒ_４は互い結合して環を形成してもよい。）
以下、本発明を詳細に説明する。

(In the formula, ring A, ring B and ring C each independently represent an aromatic ring which may contain a hetero atom. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are each independently a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 18 carbon atoms, or a C 6 to 24 carbon atom. Represents an aryl group or an aryloxy group having 6 to 24 carbon atoms, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ each independently an aryl group optionally having a substituent having 6 to 40 carbon atoms, or It represents a heteroaryl group which may have a substituent having 5 to 40 carbon atoms, wherein R ₃ or R ₄ and R ₅ or R ₆ may be bonded to each other to form a ring. ₁ and Ar ₂ , and Ar ₃ and Ar ₄ may be bonded to each other to form a ring.
Hereinafter, the present invention will be described in detail.

  In the amine compound represented by the general formula (1) of the present invention, ring A, ring B and ring C each independently represent an aromatic ring which may contain a hetero atom. Specific examples include, but are not limited to, benzene ring, naphthalene ring, anthracene ring, triphenylene ring, fluorene ring, pyridine ring, pyrazine ring, quinoline ring, pyrrole ring, indole ring, carbazole ring, furan ring. Benzofuran ring, dibenzofuran ring and the like.

In the amine compound represented by the general formula (1) of the present invention, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are each independently a hydrogen atom, A linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aryloxy group having 6 to 24 carbon atoms Represents a group. Examples of the linear, branched or cyclic alkyl group having 1 to 18 carbon atoms include, but are not limited to, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec- Butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, stearyl, trichloromethyl, trifluoromethyl, cyclopropyl, cyclohexyl, 1,3-cyclohexadienyl, 2- A cyclopenten-1-yl group etc. can be illustrated.

  The linear, branched or cyclic alkoxy group having 1 to 18 carbon atoms is not limited to the following, and specifically includes a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and an n-butoxy group. , Sec-butoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, stearyloxy group, trifluoromethoxy group and the like.

  Examples of the aryl group having 6 to 24 carbon atoms include, but are not limited to, phenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethyl. Phenyl group, 3-ethylphenyl group, 2-ethylphenyl group, 4-n-propylphenyl group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-tert-butylphenyl group, 4-cyclopentylphenyl group 4-cyclohexylphenyl group, 2,4-dimethylphenyl group, 3,5-dimethylphenyl group, 3,4-dimethylphenyl group, 1-biphenyl group, 1-naphthyl group, 2-naphthyl group, 9-phenanthryl group , 9,9-dialkyl-fluoren-2-yl group, 9,9-di-trifluoromethyl-fluoren-2-yl group, etc. It can be.

  Examples of the aryloxy group having 6 to 24 carbon atoms include, but are not limited to, phenoxy group, p-tert-butylphenoxy group, 3-fluorophenoxy group, 4-fluorophenoxy group, and the like. Can be illustrated.

R ₃ or R ₄ and R ₅ or R ₆ can be bonded to each other to form a ring.

In the amine compound represented by the general formula (1) of the present invention, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ are each independently an aryl group which may have a substituent having 6 to 40 carbon atoms, or The heteroaryl group which may have a C5-C40 substituent may be represented. The aryl group which may have a substituent having 6 to 40 carbon atoms is not limited to the following, and specifically, a phenyl group, a naphthyl group, or a biphenylyl group which may have a substituent. Terphenyl group, biphenylenyl group, anthryl group, triphenylenyl group, fluorenyl group, benzofluorenyl group, phenanthryl group, pyrenyl group, chrysenyl group, perylenyl group, picenyl group, etc. , Phenyl group, 1-naphthyl group, 2-naphthyl group, 2-anthryl group, 9-anthryl group, 2-fluorenyl group, phenanthryl group, pyrenyl group, chrysenyl group, perylenyl group, picenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethylphenyl group, 3-ethylphenyl group, 2-ethyl Enyl group, 4-n-propylphenyl group, 4-isopropylphenyl group, 2-isopropylphenyl group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-sec-butylphenyl group, 2-sec-butyl Phenyl group, 4-tert-butylphenyl group, 3-tert-butylphenyl group, 2-tert-butylphenyl group, 4-n-pentylphenyl group, 4-isopentylphenyl group, 2-neopentylphenyl group, 4 -Tert-pentylphenyl group, 4-n-hexylphenyl group, 4- (2'-ethylbutyl) phenyl group, 4-n-heptylphenyl group, 4-n-octylphenyl group, 4- (2'-ethylhexyl) Phenyl group, 4-tert-octylphenyl group, 4-n-decylphenyl group, 4-n-dodecylphenyl group 4-n-tetradecylphenyl group, 4-cyclopentylphenyl group, 4-cyclohexylphenyl group, 4- (4′-methylcyclohexyl) phenyl group, 4- (4′-tert-butylcyclohexyl) phenyl group, 3- Cyclohexylphenyl group, 2-cyclohexylphenyl group, 4-ethyl-1-naphthyl group, 6-n-butyl-2-naphthyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 3,4- Dimethylphenyl group, 3,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2,4-diethylphenyl group, 2,3,5-trimethylphenyl group, 2,3,6-trimethylphenyl group, 3, 4,5-trimethylphenyl group, 2,6-diethylphenyl group, 2,5-diisopropylphenyl group, 2,6-diisobutyl Phenyl group, 2,4-di-tert-butylphenyl group, 2,5-di-tert-butylphenyl group, 4,6-di-tert-butyl-2-methylphenyl group, 5-tert-butyl-2 -Methylphenyl group, 4-tert-butyl-2,6-dimethylphenyl group, 9-methyl-2-fluorenyl group, 9-ethyl-2-fluorenyl group, 9-n-hexyl-2-fluorenyl group, 9-dimethyl-2-fluorenyl group, 9,9-diethyl-2-fluorenyl group, 9,9-di-n-propyl-2-fluorenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxy Phenyl group, 4-ethoxyphenyl group, 3-ethoxyphenyl group, 2-ethoxyphenyl group, 4-n-propoxyphenyl group, 3-n-propoxyphenyl group, 4 -Isopropoxyphenyl group, 2-isopropoxyphenyl group, 4-n-butoxyphenyl group, 4-isobutoxyphenyl group, 2-sec-butoxyphenyl group, 4-n-pentyloxyphenyl group, 4-isopentyloxy Phenyl group, 2-isopentyloxyphenyl group, 4-neopentyloxyphenyl group, 2-neopentyloxyphenyl group, 4-n-hexyloxyphenyl group, 2- (2′-ethylbutyl) oxyphenyl group, 4- n-octyloxyphenyl group, 4-n-decyloxyphenyl group, 4-n-dodecyloxyphenyl group, 4-n-tetradecyloxyphenyl group, 4-cyclohexyloxyphenyl group, 2-cyclohexyloxyphenyl group, 2 -Methoxy-1-naphthyl group, 4-methoxy-1-naphthyl group, 4- n-butoxy-1-naphthyl group, 5-ethoxy-1-naphthyl group, 6-methoxy-2-naphthyl group, 6-ethoxy-2-naphthyl group, 6-n-butoxy-2-naphthyl group, 6-n -Hexyloxy-2-naphthyl group, 7-methoxy-2-naphthyl group, 7-n-butoxy-2-naphthyl group, 2-methyl-4-methoxyphenyl group, 2-methyl-5-methoxyphenyl group, 3 -Methyl-4-methoxyphenyl group, 3-methyl-5-methoxyphenyl group, 3-ethyl-5-methoxyphenyl group, 2-methoxy-4-methylphenyl group, 3-methoxy-4-methylphenyl group, 2 , 4-dimethoxyphenyl group, 2,5-dimethoxyphenyl group, 2,6-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 3,5 Diethoxyphenyl group, 3,5-di-n-butoxyphenyl group, 2-methoxy-4-ethoxyphenyl group, 2-methoxy-6-ethoxyphenyl group, 3,4,5-trimethoxyphenyl group, 4- Biphenylyl group, 3-biphenylyl group, 2-biphenylyl group, 4- (4′-methylphenyl) phenyl group, 4- (3′-methylphenyl) phenyl group, 4- (4′-methoxyphenyl) phenyl group, 4 -(4'-n-butoxyphenyl) phenyl group, 2- (2'-methoxyphenyl) phenyl group, 3-methyl-4-phenylphenyl group, 3-methoxy-4-phenylphenyl group, terphenyl group, 3 , 5-diphenylphenyl group, 10-phenylanthryl group, 10- (3,5-diphenylphenyl) -9-anthryl group, 9-phenyl-2-fluoreni And the like. Further, the heteroaryl group which may have a substituent having 5 to 40 carbon atoms is not limited to the following, but specifically, at least one selected from an oxygen atom, a nitrogen atom and a sulfur atom. Aromatic groups containing two heteroatoms, such as 4-quinolyl, 4-pyridyl, 3-pyridyl, 2-pyridyl, 3-furyl, 2-furyl, 3-thienyl, 2 Examples include heterocyclic groups such as -thienyl group, 2-oxazolyl group, 2-thiazolyl group, 2-benzoxazolyl group, 2-benzothiazolyl group, 2-benzoimidazolyl group. Ar ₁ and Ar ₂ , and Ar ₃ and Ar ₄ can be bonded to each other to form a ring. The ring formed by Ar ₁ and Ar ₂ and Ar ₃ and Ar ₄ is not limited to the following, but specific examples include a carbazole ring, a phenothiazine ring, a phenoxazine ring, and the like. .

  Moreover, the amine compound represented by following General formula (2) can be mentioned as a preferable specific example of the amine compound represented by the said General formula (1).

一般式（２）で表されるアミン化合物において、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９Ａｒ_１、Ａｒ_２、Ａｒ_３及びＡｒ_４は、前記一般式（１）で表されるアミン化合物と同じ基を表す。

In the amine compound represented by the general formula (2), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ , R ₉ Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ Represents the same group as the amine compound represented by the general formula (1).

  The triquinane compound (3), which is an intermediate of the amine compound represented by the general formula (1) of the present invention, can be synthesized by cyclizing the compound represented by the following general formula (4).

（式中、環Ａ、環Ｂ、環Ｃ、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８及びＲ_９は前記一般式（１）で表されるアミン化合物と同じ基を表す。また、Ｘ₁及びＸ_２は各々独立して塩素原子、臭素原子、ヨウ素原子、又はトリフルオロメタンスルホニルオキシ基を表す。）
化合物（４）は、公知の方法によって合成することができる（例えば、非特許文献２〜４参照）。

(In the formula, ring A, ring B, ring C, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are represented by the general formula (1). And represents the same group as the amine compound, and X ₁ and X ₂ each independently represent a chlorine atom, a bromine atom, an iodine atom, or a trifluoromethanesulfonyloxy group.
A compound (4) is compoundable by a well-known method (for example, refer nonpatent literature 2-4).

Angew. Chem. Int. Ed. Engl. 1984, 23, 508. Chem. Ber. 1992, 125, 1449. J. et al. Chem. Soc. PERKIN TRANS. 1995, Item 721 The triquinane compound represented by the general formula (3) of the present invention is synthesized by cyclizing the diol compound represented by the general formula (4) in an organic solvent in the presence of an acid catalyst. I can do it.

  The acid catalyst is not particularly limited, but iron compounds such as iron (III) chloride and iron (III) bromide, zinc compounds such as zinc chloride and zinc bromide, zirconium compounds such as zirconium chloride, and chlorides. Titanium compounds such as titanium, titanium bromide and titanium ethoxide, aluminum compounds such as aluminum chloride and aluminum bromide, boron trifluoride, boron trifluoride / ether complex, boron trifluoride / acetic acid complex, boron tribromide Boron compounds such as lanthanoid metal salts such as scandium chloride and lanthanum chloride, Bronsted acids such as sulfuric acid, hydrochloric acid, phosphoric acid, polyphosphoric acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, niobic acid, silica alumina , Silica titania, silica zirconia, titania zirconia, aluminum phosphate, ortho Aluminum acid catalyst, iron phosphate, aluminum sulfate, sulfate ion supported zirconia, sulfate ion supported titania, antimony pentafluoride supported silica alumina, acid clay, kaolin, montmorillonite, fluorinated sulfone resin, zeolite, strongly acidic cation exchange resin And solid acids such as heteropolyacid salts. Of these, Bronsted acid is preferable, and sulfuric acid is particularly preferable.

  The amount of Lewis acid or Bronsted acid used is not particularly limited, but is usually 0.5 to 20 times mol, preferably 2 with respect to 1 mol of the diol compound represented by the general formula (4). It is the range of 10 times mole.

  The amount of the solid acid used is not particularly limited, but is usually in the range of 0.01 to 20% by weight with respect to the amount of the diol compound represented by the general formula (4) as a raw material. Is in the range of 0.1 to 10% by weight.

  The cyclization reaction in the present invention can be carried out in the liquid phase or in the gas phase, but the liquid phase reaction is preferred. The reaction can also be carried out in a batch, continuous or fixed bed flow system.

  The cyclization reaction in the liquid phase is carried out in an organic solvent. The organic solvent is not particularly limited as long as it does not inhibit the reaction, but is usually a protonic acid solvent such as formic acid, acetic acid, propionic acid, a halogen-based solvent such as dichloromethane, chloroform, carbon tetrachloride, benzene, toluene, xylene. An aromatic hydrocarbon solvent such as mesitylene can be preferably used.

  The cyclization reaction can be performed under an atmospheric pressure, an inert gas atmosphere such as nitrogen or argon, or can be performed under pressure. In addition, although reaction is performed in the temperature range of -10-300 degreeC, More preferably, it is a temperature range of 0-200 degreeC.

  The time required for the reaction varies depending on the amount of the compound (4) and acid catalyst used, the reaction temperature, and the like, and is not necessarily limited, but is, for example, 1 to 40 hours.

  The thus obtained triquinane compound (3) is used not only as an intermediate of the organic EL material of the present invention, but also as an intermediate for electronic materials such as solar cells, an intermediate for supramolecular construction, and an intermediate for medical and agricultural chemicals. Can be used.

  The amine compound represented by the general formula (1) of the present invention is an amine compound represented by the following general formulas (5) and (6), and is a triquinane by a known method (for example, see Non-Patent Document 5). The compound (3) can be efficiently synthesized by amination. At this time, the compounds (5) and (6) may be different or the same. The amine compound represented by the general formula (1) obtained from the reaction may have a single structure, but when the compound (5) and the compound (6) are different, they can be obtained as a mixture corresponding to them.

（式中、Ａｒ_１、Ａｒ_２、Ａｒ_３及びＡｒ_４は一般式（１）で表されるアミン化合物と同じ基を表す。）
一般式（１）で表されるアミン化合物は、具体的には、以下に挙げるルートで製造することが出来る。

(In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ represent the same group as the amine compound represented by the general formula (1).)
Specifically, the amine compound represented by the general formula (1) can be produced by the following route.

  Route A: A route in which compound (3), compound (5) and compound (6) are mixed and reacted to obtain compound (1).

  Route B: Among the reaction products of the compound (3) and the compound (5), the components reacted in a one-to-one relationship are isolated and purified, and the compound (6) is reacted with the isolated product to react with the compound (1). Get route.

  Route C: Among the reaction products of the compound (3) and the compound (6), the components reacted in a one-to-one manner are isolated and purified, and the compound (5) is reacted with the isolated product to give the compound (1) Get route.

  Route D: a route in which compound (3) and compound (5) are reacted, and the resulting product is directly reacted with compound (6) to obtain compound (1).

  Route E: Route in which compound (3) and compound (6) are reacted, and the resulting product is directly reacted with compound (5) to obtain compound (1).

  An amine compound (1) suitable for the organic EL material of the present invention can be obtained by removing unreacted raw materials and unnecessary by-products from the final product obtained by any one of the above routes by column chromatography or the like. I can do it.

  When the compound (5) and the compound (6) are the same or when amination is performed by the route B or route C, the compound (1) with high purity can be obtained. On the other hand, in the case of Route A, Route D or Route E, the amine compound (1) is a mixture corresponding to the raw material compound used.

  As for the usage-amount of the compounds (5) and (6) in this amination reaction, 1-1.2 times mole is preferable with respect to 1 mol of compound (3) all.

  This amination reaction can be carried out in an organic solvent in the presence of a palladium compound, a trialkylphosphine and a base.

  Although it does not specifically limit as a palladium compound, As a specific example, palladium chloride (II), palladium bromide (II), palladium acetate (II), palladium (II) acetylacetonate, dichlorobis (benzonitrile) palladium (II) , Dichlorobis (acetonitrile) palladium (II), dichlorobis (triphenylphosphine) palladium (II), dichlorotetraamminepalladium (II), dichloro (cycloocta-1,5-diene) palladium (II), palladium (II) trifluoroacetate Divalent palladium compounds such as tris (dibenzylideneacetone) dipalladium (0), tris (dibenzylideneacetone) dipalladium (0) chloroform complex, tetrakis (triphenylphosphine) palladium ( ), Palladium - can be mentioned 0-valent palladium compounds such as carbon. Of these, palladium (II) acetate or tris (dibenzylideneacetone) dipalladium (0) is particularly preferable. Although the usage-amount of a palladium compound is not specifically limited, It is 0.001-10 mol% in conversion of palladium with respect to the amine represented by the said General formula (5) and (6), More preferably, It is 0.005 to 5 mol% in terms of palladium. If it is in the range of 0.001 to 10 mol%, sufficient catalytic activity can be obtained and economically preferable.

Specific examples of trialkylphosphines used as a ligand for palladium are not particularly limited, but include triethylphosphine, tri-n-butylphosphine, n-butyl-di (1-adamantyl) phosphine, tri- Examples thereof include tert-butylphosphine and tricyclohexylphosphine, and tri-tert-butylphosphine is particularly preferably used because of its good reactivity. Although the usage-amount of a trialkylphosphine is not specifically limited, The range of 0.5-5 times mole with respect to 1 mol of palladium metals, Preferably it is 1-4 times mole. Here, if it is the range of 1-4 times mole, sufficient catalyst activity will be obtained and it is economically preferable.
In this amination reaction, the base used can be selected from the group consisting of organic bases and inorganic bases. Specific examples include, but are not limited to, sodium hydride, potassium hydride, lithium hydride, sodium amide, potassium amide, lithium amide, potassium carbonate, sodium carbonate, lithium carbonate, rubidium carbonate, cesium carbonate, potassium bicarbonate, carbonate Sodium hydrogen, sodium metal, potassium metal, lithium metal, methoxy sodium, methoxy potassium, ethoxy sodium, ethoxy potassium, ethoxy lithium, tert-butoxy lithium, tert-butoxy sodium, tert-butoxy potassium and the like can be mentioned. Of these, tert-butoxy sodium is preferably used. Although the usage-amount of these bases is not specifically limited, It is 1-5 times mole with respect to 1 mol of compounds represented by General formula (3).
Moreover, this amination reaction is normally implemented in a reaction solvent. The reaction solvent is not particularly limited as long as it does not inhibit the reaction. Specific examples include aromatic hydrocarbon solvents such as benzene, toluene and xylene, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, acetonitrile, dimethylformamide, Examples thereof include dimethyl sulfoxide and hexamethylphosphotriamide. Of these, aromatic hydrocarbon solvents such as benzene, toluene and xylene are preferably used. Here, the solvent may be used as a single solvent or a mixed solvent. Although the usage-amount of a reaction solvent is not specifically limited, It is 2-20 weight ratio with respect to the compound represented by General formula (3).

  The amination reaction is usually carried out under normal pressure and an inert gas atmosphere such as nitrogen or argon, but can also be carried out under pressurized conditions. The reaction is carried out in the temperature range of 20 to 300 ° C, more preferably in the temperature range of 50 to 200 ° C.

  The reaction time varies depending on the reaction temperature, the amount of the compounds (3), (5), (6) and the palladium compound used, and is not particularly limited, but is, for example, several minutes to 72 hours.

Tetrahedron Letters, 1998, 39, 2367 (amination reaction) Specific examples of the amine compound represented by the general formula (1) are shown below, but are not limited thereto.

本発明の前記一般式（１）で表されるアミン化合物は、有機ＥＬ素子の発光層、正孔輸送層又は正孔注入層として使用することができる。

The amine compound represented by the general formula (1) of the present invention can be used as a light emitting layer, a hole transport layer or a hole injection layer of an organic EL device.

  In particular, since the amine compound represented by the general formula (1) is excellent in hole transport ability, when used as a hole transport layer and / or a hole injection layer, the driving voltage of the organic EL device is reduced, High luminous efficiency and improved durability can be realized.

  For the light emitting layer when the amine compound represented by the general formula (1) is used as a hole injection layer and / or a hole transport layer of an organic EL device, a conventionally known light emitting material is used. can do. The light emitting layer may be formed of only one kind of light emitting material, or one or more kinds of light emitting materials may be doped in the host material.

  In recent years, an organic EL element using a phosphorescent material as a light emitting material has attracted attention because it can realize high luminous efficiency. However, the amine compound represented by the general formula (1) may be used in combination with a phosphorescent material. it can.

  When forming the hole injection layer and / or hole transport layer made of the amine compound represented by the general formula (1), two or more kinds of materials may be contained or laminated as necessary. For example, oxides such as molybdenum oxide, 7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, hexacyanohexahexa A known electron-accepting material such as azatriphenylene may be contained or laminated.

  When the amine compound represented by the general formula (1) is used as the light emitting layer of the organic EL device, the amine compound is used alone, doped into a known light emitting host material, or known fluorescent or phosphorescent. It can be used by doping the material.

  As a method for forming a hole injection layer, a hole transport layer or a light emitting layer containing the amine compound represented by the general formula (1), for example, a known method such as a vacuum deposition method, a spin coating method, a casting method or the like Can be applied.

  Since the amine compound represented by the general formula (1) according to the present invention has a triplet level higher than that of conventional materials, it exhibits high external quantum efficiency in organic EL elements, particularly organic EL elements using phosphorescent materials. It becomes possible to make it.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples at all.

  The analytical instruments and measurement methods used in this example are listed below.

[Material purity measurement (HPLC analysis)]
Measuring device: Tosoh Multi Station LC-8020
Measuring method: Column Inertsil ODS-3V (4.6 mmΦ × 250 mm)
Detector UV detection (wavelength 254nm)
Eluent Methanol / Tetrahydrofuran = 9/1 (v / v ratio)
[Phosphorescence spectrum measurement]
Measuring device: JASCO Corporation spectrofluorimeter FP-6500
[NMR measurement]
Measuring device: Gemini200 manufactured by Varian
[Current-voltage characteristics and light emission characteristics of organic EL elements]
Measuring device: Keithley Instruments source meter (2400)
Luminance meter LUMINANCE METER (BM-9) made by TOPCON
[Glass transition temperature measurement]
Measuring device: DSC-3100 manufactured by Mac Science
Measuring method: Measured at a heating rate of 10 ° C / min under a nitrogen stream

合成例１ 化合物（Ｂ−１）の合成
窒素雰囲気下、攪拌装置を備えた１Ｌ３つ口フラスコ中に、１，３−インダンジオン ２１．２ｇ（１４４ｍｍｏｌ）、アセトニトリル ２５０ｍＬ、フッ化カリウム ４２．０ｇ（７２３ｍｍｏｌ）を加え、室温で１０分間攪拌した。この溶液に、ｐ−ブロモベンジルブロミド ７２．６ｇ（２９０ｍｍｏｌ）をアセトニトリル ２５０ｍＬに溶解させた溶液を、９０分かけて滴下した。滴下終了後、さらに室温で７時間攪拌した。反応終了後、純水 ６００ｍＬを添加し、室温で１時間攪拌した。析出した黄色粉末をろ取し、純水 ５００ｍＬで洗浄した。さらに、得られた黄色粉末をエタノールで再結晶精製し、淡黄色粉末 ６２．１ｇを得た（収率 ８９％、純度 ９９．８％）。^１Ｈ−ＮＭＲ及び^１３Ｃ−ＮＭＲ分析から、得られた淡黄色粉末は目的の化合物（Ｂ−１）であることを確認した。

Synthesis Example 1 Synthesis of Compound (B-1) In a 1 L three-necked flask equipped with a stirrer in a nitrogen atmosphere, 21.2 g (144 mmol) of 1,3-indandione, 250 mL of acetonitrile, 42.0 g of potassium fluoride ( 723 mmol) and stirred at room temperature for 10 minutes. A solution prepared by dissolving 72.6 g (290 mmol) of p-bromobenzyl bromide in 250 mL of acetonitrile was added dropwise to this solution over 90 minutes. After completion of dropping, the mixture was further stirred at room temperature for 7 hours. After completion of the reaction, 600 mL of pure water was added and stirred at room temperature for 1 hour. The precipitated yellow powder was collected by filtration and washed with 500 mL of pure water. Further, the obtained yellow powder was recrystallized and purified with ethanol to obtain 62.1 g of a pale yellow powder (yield 89%, purity 99.8%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained pale yellow powder was the target compound (B-1).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 3.18 (s 4H), 6.83 to 6.87 (d 4H), 7.12 to 7.16 (d 4H), 7.56 to 7 .68 (m 4H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 40.69, 61.64, 120.90, 122.55, 131.17, 131.52, 134.08, 135.64, 142.45, 202 .84
Synthesis Example 2 Synthesis of Compound (B-2) In a 1 L three-necked flask equipped with a stirrer in a nitrogen atmosphere, 15.0 g (31.0 mmol) of compound (B-1), 150 mL of tetrahydrofuran, and 150 mL of methanol were added. Stir at room temperature for 10 minutes. To this solution, 8.8 g (233 mmol) of sodium borohydride was slowly added over 1 hour, and further stirred at room temperature for 1 hour. After completion of the reaction, the reaction vessel was cooled to 0 ° C., and 75 mL of 10% aqueous hydrogen chloride solution was slowly added. 250 mL of pure water was added and extracted with 300 mL of dichloromethane. The obtained organic layer was washed and separated with 500 mL of pure water and then with saturated brine, and dried over anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain 14.9 g of a yellow oil (yield 99%, purity 99.6%). The resulting yellow oil was recrystallized with a mixed solution of isopropanol / tetrahydrofuran to isolate one diastereomer as white crystals. ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained white crystals were the target compound (B-2).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 1.46 to 1.49 (d 2H), 2.89 (s 4H), 5.10 to 5.13 (d 2H), 7.04 to 7 .35 (m 12H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 37.16, 55.91, 78.82, 120.11, 124.16, 128.79, 131.13, 132.16, 137.71, 142 .80
Example 1 Synthesis of Compound (B-3) Under a nitrogen atmosphere, 4.0 g (41 mmol) of sulfuric acid and 200 mL of dichloromethane were added to a 500 mL three-necked flask equipped with a stirrer, and stirred at room temperature for 5 minutes. A solution prepared by dissolving 10 g (29 mmol) of the compound (B-2) in 70 mL of dichloromethane was added dropwise to this solution over 1 hour. After completion of dropping, the mixture was further stirred at 45 ° C. for 20 hours. After completion of the reaction, 200 mL of pure water was added and the solution was separated. Further, after washing and separating with saturated brine, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography and recrystallized from toluene to obtain 7.1 g of a white solid (yield 77%, purity 99.9%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (B-3).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 3.03 to 3.30 (4H), 4.40 (s 2H), 7.02 to 7.06 (d 2H), 7.19 to 7. 36 (m 6H), 7.48 (s 2H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 43.71, 61.77, 63.73, 120.53, 124.56, 126.39, 127.77, 130.13, 141.37, 143 .20, 145.95
Example 2 Synthesis of Compound (A-1) In a 100 mL four-necked flask equipped with a stirrer in a nitrogen atmosphere, 0.70 g (1.5 mmol) of compound (B-3), 0.58 g (3.41 mmol) of diphenylamine ), 1.51 g (4.64 mmol) of cesium carbonate, 7 mg (0.03 mmol) of palladium (II) acetate, 20 mg (0.1 mmol) of tri-tert-butylphosphine, and 10 mL of o-xylene, and added at 120 ° C. for 15 hours. Stir. After completion of the reaction, 30 mL of pure water and 30 mL of toluene were added to separate the solution. Furthermore, after washing and separating with 30 mL of pure water and then with saturated saline, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography to obtain 0.72 g of a white solid (yield 74%, purity 99.6%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-1). From the DSC analysis, the glass transition temperature of the compound (A-1) was 120 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 3.09 to 3.38 (4H), 4.40 (s 2H), 6.86 to 7.26 (m 30H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 44.59, 62.50, 63.25, 120.99, 122.22, 123.65, 123.92, 124.38, 125.29, 127 .20, 129.05, 137.42, 144.01, 145.14, 146.74, 148.00
Example 3 Synthesis of Compound (A-4) In Example 2, the same experimental operation was performed except that 0.64 g (3.24 mmol) of di-p-tolylamine was used instead of diphenylamine, and a white solid was reduced to 0. 0.74 g was obtained (yield 70%, purity 99.4%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-4). From the DSC analysis, the glass transition temperature of the compound (A-4) was 124 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.30 (s 12H), 3.07 to 3.36 (4H), 4.38 (s 2H), 6.80 to 7.25 (m 26H )
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 20.88, 44.59, 62.54, 63.29, 119.95, 122.91, 123.86, 124.40, 125.09, 127 .11, 129.65, 131.68, 136.52, 144.10, 144.96, 145.69, 147.14
Example 4 Synthesis of Compound (A-5)
In Example 2, the same experimental operation was performed except that 0.80 g (3.24 mmol) of N- (4-biphenylyl) aniline was used instead of diphenylamine, to obtain 0.98 g of white powder (yield 84). %, Purity 99.2%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-5). From the DSC analysis, the glass transition temperature of compound (A-5) was 136 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 3.11 to 3.40 (4H), 4.42 (s 2H), 6.91 to 7.60 (m 38H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 44.63, 62.53, 63.29, 121.19, 122.53, 123.39, 123.97, 124.14, 124.43, 125 .40, 126.57, 126.70, 127.27, 127.62, 128.70, 129.14, 134.63, 137.67, 140.66, 144.01, 145.22, 146.57 , 147.34, 147.83

合成例３ 化合物（Ｃ−１）の合成
窒素雰囲気下、攪拌装置を備えた１Ｌ３つ口フラスコ中に、１，３−インダンジオン １４．７ｇ（１００ｍｍｏｌ）、アセトニトリル ３００ｍＬ、フッ化カリウム ２９．２ｇ（５０２ｍｍｏｌ）を加え、室温で１０分間攪拌した。この溶液に、ｏ−ブロモベンジルブロミド ５０．６ｇ（２０２ｍｍｏｌ）をアセトニトリル １２０ｍＬに溶解させた溶液を、４０分かけて滴下した。滴下終了後、さらに室温で１５時間攪拌した。反応終了後、純水 １０００ｍＬを添加し、室温で１時間攪拌した。析出した黄色粉末をろ取し、純水 ５００ｍＬで洗浄した。さらに、得られた黄色粉末をエタノールで再結晶精製し、淡肌色粉末 ４２．３ｇを得た（収率 ８７％、純度 ９９．９％）。^１Ｈ−ＮＭＲ及び^１３Ｃ−ＮＭＲ分析から、得られた淡黄色粉末は目的の化合物（Ｃ−１）であることを確認した。

Synthesis Example 3 Synthesis of Compound (C-1) In a 1 L three-necked flask equipped with a stirrer in a nitrogen atmosphere, 14.7 g (100 mmol) of 1,3-indandione, 300 mL of acetonitrile, 29.2 g of potassium fluoride ( 502 mmol) was added and stirred at room temperature for 10 minutes. A solution prepared by dissolving 50.6 g (202 mmol) of o-bromobenzyl bromide in 120 mL of acetonitrile was added dropwise to this solution over 40 minutes. After completion of dropping, the mixture was further stirred at room temperature for 15 hours. After completion of the reaction, 1000 mL of pure water was added and stirred at room temperature for 1 hour. The precipitated yellow powder was collected by filtration and washed with 500 mL of pure water. Furthermore, the obtained yellow powder was recrystallized and purified with ethanol to obtain 42.3 g of a pale skin powder (yield 87%, purity 99.9%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained pale yellow powder was the target compound (C-1).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 3.51 (s 4H), 6.87 to 7.09 (m 4H), 7.39 to 7.43 (4H), 7.64 to 7. 82 (m 4H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 39.67, 59.92, 122.97, 125.66, 126.92, 128.42, 131.32, 133.13, 135.22, 135 .40, 142.14, 201.56
Synthesis Example 4 Synthesis of Compound (C-2) In a 1 L three-necked flask equipped with a stirrer under a nitrogen atmosphere, 42.2 g (87.2 mmol) of Compound (C-1), 230 mL of tetrahydrofuran, and 230 mL of methanol were added. Stir at room temperature for 10 minutes. To this solution, 16.5 g (436 mmol) of sodium borohydride was slowly added over 1 hour 30 minutes, and further stirred at room temperature for 1 hour. After completion of the reaction, the reaction vessel was cooled to 0 ° C., and 100 mL of 10% aqueous hydrogen chloride solution was slowly added. 150 mL of pure water was added and extracted with 300 mL of dichloromethane. The obtained organic layer was washed and separated with 300 mL of pure water and then with saturated brine, and dried over anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain 42.4 g of a white powder (yield 99%, purity 99.5%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white powder was the target compound (C-2).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.15 to 2.18 (d 2H), 3.21 to 3.39 (4H), 5.34 to 5.36 (d 2H), 86-7.07 (m 8H), 7.34-7.44 (m 4H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 36.66, 58.36, 78.38, 123.68, 125.75, 126.78, 127.42, 128.30, 132.54, 133 .00, 138.64, 143.29
Example 5 Synthesis of Compound (C-3) In a nitrogen atmosphere, 29.8 g (304 mmol) of sulfuric acid and 400 mL of dichloromethane were added to a 1 L three-necked flask equipped with a stirrer and stirred at room temperature for 10 minutes. A solution prepared by dissolving 42.4 g (86.8 mmol) of compound (C-2) in 220 mL of dichloromethane was added dropwise to this solution over 1 hour and 30 minutes. After completion of dropping, the mixture was further stirred at 45 ° C. for 17 hours. After completion of the reaction, 400 mL of distilled water was added and the solution was separated. Further, after washing and separating with saturated brine, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography and recrystallized from toluene to obtain 11.0 g of a white powder (yield 28%, purity 99.9%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (C-3).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 3.17 to 3.44 (4H), 4.58 (s 2H), 7.04 to 7.36 (m 10H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 46.04, 60.76, 63.31, 120.11, 123.39, 124.45, 127.64, 128.75, 130.18, 142 .73, 143.48, 145.47
Example 6 Synthesis of Compound (A-21) In a 100 mL four-necked flask equipped with a stirrer under a nitrogen atmosphere, 2.00 g (4.42 mmol) of compound (C-3), 1.57 g (9.38 mmol) of diphenylamine. ), Sodium tert-butoxide 1.02 g (10.6 mmol), palladium acetate (II) 20 mg (0.089 mmol), tri-tert-butylphosphine 70 mg (0.35 mmol), o-xylene 30 mL, and 120 ° C. For 3 hours. After completion of the reaction, 50 mL of distilled water and 50 mL of toluene were added to separate the solution. Further, after washing and separating with 50 mL of pure water and then with saturated saline, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography to obtain 2.34 g of a white powder (yield 84%, purity 98.7%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-21). From the DSC analysis, the glass transition temperature of the compound (A-21) was 113 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.27 to 2.83 (4H), 4.30 (s 2H), 6.89 to 7.41 (m 30H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 42.87, 62.06, 62.39, 121.06, 121.80, 122.38, 124.54, 125.73, 127.27, 128 .28, 128.97, 139.25, 143.20, 143.95, 145.99, 147.14
Example 7 Synthesis of Compound (A-22) In Example 6, the same experimental operation was carried out except that 1.76 g (8.92 mmol) of di-p-tolylamine was used instead of diphenylamine. .70 g was obtained (yield 97%, purity 98.8%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-22). From the DSC analysis, the glass transition temperature of compound (A-22) was 117 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.26 (s 12H), 2.38 to 2.84 (4H), 4.30 (s 2H), 6.77 to 7.39 (m 26H )
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 20.88, 42.95, 62.15, 62.45, 120.55, 122.51, 124.54, 125.31, 127.22, 128 .13, 129.52, 131.06, 138.90, 143.53, 144.14, 145.03, 145.95
Example 8 Synthesis of Compound (A-26) A white powder was prepared in the same manner as in Example 6, except that 1.78 g (8.93 mmol) of p-methoxyphenylphenylamine was used instead of diphenylamine. 2.98 g was obtained (yield 98%, purity 99.6%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-26). From the DSC analysis, the glass transition temperature of the compound (A-26) was 102 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.35 to 2.85 (4H), 3.78 (s 6H), 4.31 (s 2H), 6.73 to 7.40 (m 28H )
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 43.07, 55.51, 62.14, 62.32, 114.43, 120.61, 124.52, 125.13, 125.66, 127 .22, 128.15, 128.85, 138.68, 140.38, 143.49, 144.03, 145.93, 147.78, 155.40
Example 9 Synthesis of Compound (A-27)
In Example 6, the same experimental operation was performed except that 2.05 g (8.94 mmol) of di-p-methoxyphenylamine was used instead of diphenylamine, to obtain 2.32 g of a white powder (yield 70%). , Purity 99.1%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white solid was the target compound (A-27). From the DSC analysis, the glass transition temperature of compound (A-27) was 105 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.38 to 2.81 (4H), 3.76 (s 12H), 4.28 (s 2H), 6.70 to 7.39 (m 26H )
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 43.28, 55.53, 62.23, 114.31, 119.78, 124.12, 124.49, 127.12, 127.97, 137 78, 141.39, 144.12, 145.95, 154.63

合成例５ 化合物（Ｄ−１）の合成
窒素雰囲気下、攪拌装置を備えた５００ｍＬ４つ口フラスコ中に、３−クロロ−２−メチル安息香酸 ８．１２ｇ（４７．６ｍｍｏｌ）、テトラヒドロフラン １００ｍＬを加え、反応容器を−７８℃に冷却した。この溶液に、リチウムアルミニウムヒドリド溶液 １００ｍＬ（アルドリッチ製 １．０Ｍテトラヒドロフラン溶液）を３０分かけて滴下した。滴下終了後、−７８℃で１時間攪拌し、さらに室温に戻して５時間攪拌した。反応終了後、反応容器を０℃に冷却し、３．５％塩化水素水溶液を注意深く滴下した。純水 ３００ｍＬを添加し、トルエン ５００ｍＬで抽出した。得られた有機層を飽和食塩水で洗浄分液し、無水硫酸マグネシウムで乾燥した。その後、減圧濃縮して溶媒を留去し、白色粉末 ６．９２ｇを得た（収率 ９３％、純度 ９５．５％）。^１Ｈ−ＮＭＲ及び^１３Ｃ−ＮＭＲ分析から、得られた淡黄色粉末は目的の化合物（Ｄ−１）であることを確認した。

Synthesis Example 5 Synthesis of Compound (D-1) In a 500 mL four-necked flask equipped with a stirrer under a nitrogen atmosphere, 8.12 g (47.6 mmol) of 3-chloro-2-methylbenzoic acid and 100 mL of tetrahydrofuran were added. The reaction vessel was cooled to -78 ° C. To this solution, 100 mL of lithium aluminum hydride solution (1.0M tetrahydrofuran solution manufactured by Aldrich) was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was stirred at -78 ° C for 1 hour, returned to room temperature, and stirred for 5 hours. After completion of the reaction, the reaction vessel was cooled to 0 ° C., and 3.5% aqueous hydrogen chloride solution was carefully added dropwise. 300 mL of pure water was added and extracted with 500 mL of toluene. The obtained organic layer was washed and separated with saturated brine, and dried over anhydrous magnesium sulfate. Thereafter, the solvent was distilled off under reduced pressure to obtain 6.92 g of a white powder (yield 93%, purity 95.5%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained pale yellow powder was the target compound (D-1).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.30 (s 1H), 2.44 (s 3H), 4.75 (s 2H), 7.15 to 7.41 (m 3H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 15.35, 63.78, 125.97, 126.68, 128.64, 134.08, 135.03, 140.46
Synthesis Example 6 Synthesis of Compound (D-2) In a 500 mL four-necked flask equipped with a stirrer in a nitrogen atmosphere, compound (D-1) 6.82 g (43.5 mmol), triphenylphosphine 12.6 g (47) 0.9 mmol) and diethyl ether (40 mL) were added, and the mixture was stirred at room temperature for 5 minutes. To this solution, a solution of 15.2 g (45.7 mmol) of carbon tetrabromide dissolved in 20 mL of diethyl ether was added dropwise over 20 minutes, and the mixture was further stirred at room temperature for 1 hour. After completion of the reaction, the reaction solution was filtered. The obtained filtrate was purified by silica gel column chromatography. Further, low-boiling impurities were removed by distillation under reduced pressure to obtain 7.93 g of a colorless transparent oil (yield 83%, purity 97.1%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained colorless transparent oil was the target compound (D-2).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.44 (s 3H), 4.50 (s 2H), 7.05 to 7.35 (m 3H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 15.79, 32.32, 126.89, 128.44, 129.80, 135.36, 135.49, 137.62
Synthesis Example 7 Synthesis of Compound (D-3) In a 300 mL three-neck flask equipped with a stirrer under a nitrogen atmosphere, 2.40 g (16.4 mmol) of 1,3-indandione, 40 mL of acetonitrile, potassium fluoride 4. 77 g (82.1 mmol) was added and stirred at room temperature for 10 minutes. To this solution, a solution prepared by dissolving 7.93 g (36.1 mmol) of compound (D-2) in 30 mL of acetonitrile was dropped over 15 minutes. After completion of dropping, the mixture was further stirred at room temperature for 15 hours. After completion of the reaction, 200 mL of pure water was added and stirred at room temperature for 1 hour. The precipitated yellow powder was collected by filtration and washed with 100 mL of pure water. Furthermore, the obtained yellow powder was recrystallized and purified with ethanol to obtain 5.40 g of a flesh-colored powder (yield 78%, purity 97.0%). This skin color powder was used as the compound (D-3) in the next step (Synthesis Example 8).

Synthesis Example 8 Synthesis of Compound (D-4) In a 300 mL four-necked flask equipped with a stirrer in a nitrogen atmosphere, 4.3 g (10.2 mmol) of Compound (D-3), 35 mL of tetrahydrofuran, and 35 mL of methanol were added. The reaction vessel was cooled to 0 ° C. To this solution, 3.92 g (104 mmol) of sodium borohydride was slowly added over 1 hour and 30 minutes, further stirred at room temperature for 1 hour, and disappearance of raw materials was confirmed by HPLC analysis. The reaction vessel was cooled to 0 ° C., and 30 mL of 10% aqueous hydrogen chloride solution was slowly added. 50 mL of pure water was added and extracted with 120 mL of dichloromethane. The obtained organic layer was washed and separated with 100 mL of pure water and then with saturated brine, and dried over anhydrous magnesium sulfate. Then, it concentrated under reduced pressure and the solvent was distilled off and 4.35g of pale pink powder was obtained (yield 99%, purity 96.0%). This pale pink powder was used as the compound (D-4) in the next step (Example 10).

Example 10 Synthesis of Compound (D-5) In a 300 mL three-necked flask equipped with a stirrer under a nitrogen atmosphere, 3.0 g (31 mmol) of sulfuric acid and 100 mL of dichloromethane were added and stirred at room temperature for 10 minutes. A solution prepared by dissolving 4.35 g (10.1 mmol) of the compound (D-4) in 10 mL of dichloromethane was added dropwise to this solution over 20 minutes. After completion of dropping, the mixture was further stirred at 45 ° C. for 15 hours. After completion of the reaction, 150 mL of pure water and 100 mL of dichloromethane were added and washed to separate. Further, after washing and separating with saturated brine, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography and recrystallized from toluene to obtain 1.26 g of pale yellow crystals (yield 32%, purity 99.0%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained pale yellow crystals were the target compound (D-5).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.26 (s 6H), 3.09 to 3.38 (4H), 4.44 (s 2H), 7.12 to 7.34 (m 8H )
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 16.69, 44.32, 62.32, 62.67, 122.69, 124.34, 127.47, 127.84, 132.11, 132 .91, 142.03, 143.15, 143.64
Example 11 Synthesis of Compound (A-34) In a 100 mL four-necked flask equipped with a stirrer under a nitrogen atmosphere, 0.61 g (1.56 mmol) of compound (D-5), 0.63 g of di-p-tolylamine (3.19 mmol), sodium tert-butoxide 0.36 g (3.74 mmol), palladium (II) acetate 7 mg (0.031 mmol), tri-tert-butylphosphine 25 mg (0.12 mmol), o-xylene 15 mL. In addition, the mixture was stirred at 120 ° C. for 15 hours. After completion of the reaction, 30 mL of pure water and 15 mL of toluene were added to separate the solution. Furthermore, after washing and separating with 30 mL of pure water and then with saturated saline, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography to obtain 0.86 g of white powder (yield 77%, purity 99.0%). ^{From 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white powder was the target compound (A-34). From the DSC analysis, the glass transition temperature of compound (A-34) was 147 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 1.93 (s 6H), 2.26 (s 12H), 3.08 to 3.39 (4H), 4.52 (s 2H), 81 to 7.42 (m 24H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 15.22, 20.75, 44.80, 62.45, 62.85, 121.34, 122.69, 124.51, 127.25, 128 .31, 129.45, 130.26, 132.38, 140.99, 143.46, 144.41, 144.45, 145.51

合成例９ 化合物（Ｅ−１）の合成
窒素雰囲気下、攪拌装置を備えた５００ｍＬ４つ口フラスコ中に、５−クロロ−２−メチル安息香酸 ８．１２ｇ（４７．６ｍｍｏｌ）、テトラヒドロフラン １００ｍＬを加え、反応容器を−７８℃に冷却した。この溶液に、リチウムアルミニウムヒドリド溶液 １００ｍＬ（アルドリッチ製 １．０Ｍテトラヒドロフラン溶液）を３０分かけて滴下した。滴下終了後、−７８℃で１時間攪拌し、さらに室温に戻して５時間攪拌した。反応終了後、反応容器を０℃に冷却し、３．５％塩化水素水溶液を注意深く滴下した。純水 ３００ｍＬを添加し、トルエン ５００ｍＬで抽出した。得られた有機層を飽和食塩水で洗浄分液し、無水硫酸マグネシウムで乾燥した。その後、減圧濃縮して溶媒を留去し、淡黄色オイル ７．３０ｇを得た（収率 ９８％、純度 ９８．３％）。この淡黄色オイルを化合物（Ｅ−１）として次工程（合成例１０）に用いた。

Synthesis Example 9 Synthesis of Compound (E-1) In a 500 mL four-necked flask equipped with a stirrer in a nitrogen atmosphere, 8.12 g (47.6 mmol) of 5-chloro-2-methylbenzoic acid and 100 mL of tetrahydrofuran were added. The reaction vessel was cooled to -78 ° C. To this solution, 100 mL of lithium aluminum hydride solution (1.0M tetrahydrofuran solution manufactured by Aldrich) was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was stirred at -78 ° C for 1 hour, returned to room temperature, and stirred for 5 hours. After completion of the reaction, the reaction vessel was cooled to 0 ° C., and 3.5% aqueous hydrogen chloride solution was carefully added dropwise. 300 mL of pure water was added and extracted with 500 mL of toluene. The obtained organic layer was washed and separated with saturated brine, and dried over anhydrous magnesium sulfate. Then, it concentrated under reduced pressure and the solvent was distilled off and 7.30g of pale yellow oil was obtained (yield 98%, purity 98.3%). This pale yellow oil was used as the compound (E-1) in the next step (Synthesis Example 10).

Synthesis Example 10 Synthesis of Compound (E-2) In a 500 mL four-necked flask equipped with a stirrer in a nitrogen atmosphere, 7.30 g (46.6 mmol) of compound (E-1), 13.5 g of triphenylphosphine (51 0.5 mmol) and 70 mL of diethyl ether were added and stirred at room temperature for 5 minutes. To this solution, a solution of 16.2 g (48.8 mmol) of carbon tetrabromide dissolved in 20 mL of diethyl ether was added dropwise over 20 minutes, and the mixture was further stirred at room temperature for 1 hour. After completion of the reaction, the reaction solution was filtered. The obtained filtrate was purified by silica gel column chromatography. Further, low-boiling impurities were removed by distillation under reduced pressure to obtain 10.0 g of a pale yellow oil (yield 98%, purity 98.8%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained pale yellow oil was the target compound (E-2).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.37 (s 3H), 4.43 (s 2H), 7.08 to 7.30 (m 3H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 18.33, 31.12, 128.79, 129.69, 131.63, 132.03, 135.53, 137.32.
Synthesis Example 11 Synthesis of Compound (E-3) In a 300 mL three-necked flask equipped with a stirrer under a nitrogen atmosphere, 2.90 g (19.8 mmol) of 1,3-indandione, 100 mL of acetonitrile, potassium fluoride 5. 80 g (100 mmol) was added and stirred at room temperature for 10 minutes. A solution prepared by dissolving 9.13 g (41.6 mmol) of compound (E-2) in 10 mL of acetonitrile was added dropwise to this solution over 15 minutes. After completion of dropping, the mixture was further stirred at room temperature for 15 hours. After completion of the reaction, 200 mL of pure water was added and stirred at room temperature for 1 hour. The precipitated flesh-colored powder was collected by filtration and washed with 100 mL of pure water. Furthermore, the obtained flesh-colored powder was recrystallized and purified with ethanol to obtain 4.90 g of a white powder (yield 58%, purity 95.3%). This white powder was used as the compound (E-3) in the next step (Synthesis Example 12).

Synthesis Example 12 Synthesis of Compound (E-4) In a 300 mL four-necked flask equipped with a stirrer in a nitrogen atmosphere, 4.90 g (11.6 mmol) of compound (E-3), 40 mL of tetrahydrofuran, and 40 mL of methanol were added. The reaction vessel was cooled to 0 ° C. To this solution, 3.20 g (84.6 mmol) of sodium borohydride was slowly added over 1 hour and 30 minutes, and further stirred at room temperature for 1 hour, and disappearance of raw materials was confirmed by HPLC analysis. The reaction vessel was cooled to 0 ° C., and 30 mL of 10% aqueous hydrogen chloride solution was slowly added. 50 mL of pure water was added and extracted with 150 mL of dichloromethane. The obtained organic layer was washed and separated with 100 mL of pure water and then with saturated brine, and dried over anhydrous magnesium sulfate. Then, it concentrated under reduced pressure and the solvent was distilled off and 4.94g of white powder was obtained (yield 99%, purity 96.4%). This white powder was used as the compound (E-4) in the next step (Example 12).

Example 12 Synthesis of Compound (E-5) In a nitrogen atmosphere, 5.69 g (58.0 mmol) of sulfuric acid and 120 mL of dichloromethane were added to a 200 mL three-necked flask equipped with a stirrer, and the mixture was stirred at room temperature for 10 minutes. A solution prepared by dissolving 4.94 g (11.6 mmol) of the compound (E-4) in 10 mL of dichloromethane was added dropwise to this solution over 20 minutes. After completion of dropping, the mixture was further stirred at 45 ° C. for 15 hours. After completion of the reaction, 150 mL of pure water and 100 mL of dichloromethane were added and washed to separate. Further, after washing and separating with saturated brine, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography and recrystallized from toluene to obtain 0.77 g of white crystals (yield 17%, purity 99.9%). ^{From the 1} H-NMR and ¹³ C-NMR analysis, it was confirmed that the obtained white crystals were the target compound (E-5).

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.19 (s 6H), 2.92 to 3.30 (4H), 4.67 (s 2H), 6.93 to 7.20 (m 6H ), 7.68-7.73 (m 2H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 18.85, 42.67, 61.59, 62.83, 126.98, 127.03, 127.73, 128.66, 129.50, 132 .71, 140.73, 142.82, 143.90
Example 13 Synthesis of Compound (A-38) In a 100 mL four-necked flask equipped with a stirrer under a nitrogen atmosphere, 0.61 g (1.56 mmol) of compound (E-5), 0.63 g of di-p-tolylamine (3.19 mmol), sodium tert-butoxide 0.36 g (3.74 mmol), palladium (II) acetate 7 mg (0.031 mmol), tri-tert-butylphosphine 25 mg (0.12 mmol), o-xylene 15 mL. In addition, the mixture was stirred at 120 ° C. for 15 hours. After completion of the reaction, 30 mL of pure water and 15 mL of toluene were added to separate the solution. Furthermore, after washing and separating with 30 mL of pure water and then with saturated saline, the obtained organic layer was concentrated under reduced pressure to distill off the solvent. Furthermore, the obtained residue was purified by silica gel column chromatography to obtain 0.59 g of a white powder (yield 53%, purity 99.8%). ^{From the 1} H-NMR and ¹³ C-NMR analyses, it was confirmed that the obtained white powder was the target compound (A-38). From the DSC analysis, the glass transition temperature of compound (A-38) was 149 ° C.

¹ H-NMR (CDCl ₃ ) δ (ppm) = 2.11 (s 6H), 2.26 (s 12H), 2.79 to 3.00 (4H), 3.90 (s 2H), 71-7.00 (m 22H), 7.38-7.42 (m 2H)
¹³ C-NMR (CDCl ₃ ) δ (ppm) = 18.74, 20.77, 43.22, 61.15, 61.29, 122.25, 125.71, 125.93, 126.78, 129 .21, 129.49, 130.04, 130.86, 139.76, 142.14, 143.79, 143.88, 145.11.
Example 14 Measurement of Triplet Level of Compound (A-1) In a sample tube, 1 mg of compound (A-1) and 1 mL of 2-methyltetrahydrofuran were mixed well to prepare a uniform solution. This solution was deaerated by bubbling with argon gas for 10 minutes, and then the sample tube was sealed to obtain a sample for phosphorescence spectrum measurement. When a phosphorescence spectrum was measured at a temperature of 77 K (under liquid nitrogen cooling), the triplet level of the compound (A-1) calculated from the obtained phosphorescence spectrum was 2.95 eV.

Example 15 Measurement of Triplet Level of Compound (A-4) A phosphorescence spectrum was obtained in the same manner as in Example 14 except that compound (A-4) was used instead of compound (A-1). Was measured, and the triplet level of the compound (A-4) calculated from the obtained phosphorescence spectrum was 2.93 eV.

Example 16 Measurement of Triplet Level of Compound (A-21) A phosphorescence spectrum was obtained by performing the same experimental procedure as in Example 14, except that compound (A-21) was used instead of compound (A-1). Was measured, and the triplet level of the compound (A-21) calculated from the obtained phosphorescence spectrum was 2.95 eV.

Example 17 Measurement of Triplet Level of Compound (A-22) A phosphorescence spectrum was obtained in the same manner as in Example 14 except that compound (A-22) was used instead of compound (A-1). Was measured, and the triplet level of the compound (A-22) calculated from the obtained phosphorescence spectrum was 2.94 eV.

Example 18 Measurement of Triplet Level of Compound (A-34) A phosphorescence spectrum was obtained in the same manner as in Example 14 except that compound (A-34) was used instead of compound (A-1). Was measured, and the triplet level of the compound (A-34) calculated from the obtained phosphorescence spectrum was 2.96 eV.

Example 19 Measurement of Triplet Level of Compound (A-38) A phosphorescence spectrum was obtained in the same manner as in Example 14 except that compound (A-38) was used instead of compound (A-1). Was measured, and the triplet level of the compound (A-38) calculated from the obtained phosphorescence spectrum was 2.93 eV.

Example 20 Device Evaluation of Compound (A-1) A glass substrate on which an ITO transparent electrode having a thickness of 200 nm was laminated was subjected to ultrasonic cleaning with acetone and pure water and boiling cleaning with isopropyl alcohol, and then dried. Further, UV / ozone treatment was performed, and after evacuation with a vacuum pump until it was 1 × 10 ⁻⁴ Pa after installation in a vacuum deposition apparatus. First, α-NPD was deposited on the ITO transparent electrode at a deposition rate of 0.3 nm / second to form a 20 nm hole injection layer. Next, the compound (A-1) was deposited at a deposition rate of 0.3 nm / second to form a 30 nm hole transport layer. Next, tris (2-phenylpyridine) iridium (Ir (ppy) ₃ ) that is a phosphorescent dopant material and 4,4′-bis (N-carbazolyl) biphenyl (CBP) that is a host material have a weight ratio of 1:11. Co-deposited at a deposition rate of 0.25 nm / second to obtain a 20 nm light emitting layer. Next, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was vapor-deposited at a vapor deposition rate of 0.3 nm / second to form a 10 nm excitocin block layer. Next, a tris (8-quinolinolato) aluminum complex was vapor-deposited at a vapor deposition rate of 0.3 nm / second to form a 30-nm electron transport layer. Further, lithium fluoride was deposited as an electron injection layer to a thickness of 0.5 nm at a deposition rate of 0.01 nm / second, and finally aluminum was deposited to a thickness of 100 nm at a deposition rate of 0.25 nm / second to form a cathode. In a nitrogen atmosphere, a sealing glass plate was bonded with a UV curable resin to obtain an organic EL element for evaluation. A current of 20 mA / cm ² was applied to the device thus obtained, and driving voltage and external quantum efficiency were measured. The results are shown in Table 1.

Example 21 Element Evaluation of Compound (A-4) In Example 20, an organic EL element was produced by performing the same experimental operation except that the compound (A-4) was used instead of the compound (A-1). did. A current of 20 mA / cm ² was applied, and driving voltage and external quantum efficiency were measured. The results are shown in Table 1.

Example 22 Device Evaluation of Compound (A-22) An organic EL device was produced in the same manner as in Example 20 except that compound (A-22) was used instead of compound (A-1). did. A current of 20 mA / cm ² was applied, and driving voltage and external quantum efficiency were measured. The results are shown in Table 1.

Example 23 Device Evaluation of Compound (A-34) An organic EL device was produced in the same manner as in Example 20 except that the compound (A-34) was used instead of the compound (A-1). did. A current of 20 mA / cm ² was applied, and driving voltage and external quantum efficiency were measured. The results are shown in Table 1.

Example 24 Device Evaluation of Compound (A-38) An organic EL device was produced in the same manner as in Example 20 except that the compound (A-38) was used instead of the compound (A-1). did. A current of 20 mA / cm ² was applied, and driving voltage and external quantum efficiency were measured. The results are shown in Table 1.

Comparative Example 1 Element Evaluation of α-NPD In Example 20, the same experimental operation was performed except that α-NPD was used instead of the compound (A-1), and an organic EL element was produced. A current of 20 mA / cm ² was applied, and driving voltage and external quantum efficiency were measured. The results are shown in Table 1.

  The amine compound of the present invention can be used as a hole injection material, a hole transport material or a light emitting layer host material of an organic EL device, and has a higher triplet level than a conventional material. It is expected to be an extremely useful material in the organic EL element used. Furthermore, not only as a hole injection material, a hole transport material, or a light emitting material such as an organic EL element or an electrophotographic photosensitive member, but also in a field to an organic photoconductive material such as a photoelectric conversion element, a solar cell, and an image sensor. Applicable.

Claims (4)

An amine compound represented by the general formula (2).

(Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are each independently a hydrogen atom, a linear, branched or cyclic group having 1 to 18 carbon atoms. Or a linear, branched or cyclic alkoxy group having 1 to 18 carbon atoms, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ are each independently a phenyl group, a biphenylyl group, a tolyl group, or a methoxy group Represents a phenyl group , and R ₃ and R ₅ may be bonded to each other to form a ring.) A triquinane compound represented by the general formula (3).

(In the formula, ring A, ring B and ring C represent a benzene ring. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are each independently hydrogen. An atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or a linear, branched or cyclic alkoxy group having 1 to 18 carbon atoms, wherein R ₃ and R ₅ are bonded to each other. A ring may be formed, and X ₁ and X ₂ each independently represents a chlorine atom, a bromine atom, an iodine atom, or a trifluoromethanesulfonyloxy group.) The method for producing a triquinane compound represented by the general formula (3) according to claim 2 , wherein the diol compound represented by the general formula (4) is cyclized in the presence of an acid catalyst.

(In the formula, ring A, ring B and ring C represent a benzene ring. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are each independently hydrogen. An atom, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, or a linear, branched or cyclic alkoxy group having 1 to 18 carbon atoms, wherein R ₃ and R ₅ are bonded to each other. A ring may be formed, and X ₁ and X ₂ each independently represents a chlorine atom, a bromine atom, an iodine atom, or a trifluoromethanesulfonyloxy group.) Torikinan compound represented by the following general formula represented by the general formula (3) according to claim 2 (5) and an amine compound represented by the general formula (6), a palladium compound and a trialkyl phosphinothricin down or Ranaru catalyst And a reaction in the presence of a base, the method for producing an amine compound represented by the general formula (1) according to claim 1.

(In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ each independently represent a phenyl group, a biphenylyl group, a tolyl group, or a methoxyphenyl group .)