JP4016301B2 - Novel azo group-containing aromatic compound and process for producing the same - Google Patents

Description

【０００５】
【発明が解決しようとする課題】
式（１）のようなアゾベンゼンの２つのベンゼン環の両方のベンゼン環上にアミノフェノキシ基をそれぞれ１個もつ化合物を合成することは、上記文献によればできるが、アゾベンゼンの２つのベンゼン環の一方のベンゼン環上にアミノフェノキシ基を２個もつ化合物を合成することはできない。本発明は、アゾベンゼンの２つのベンゼン環のうちの一方のベンゼン環上にアミノフェノキシ基を２個もつ化合物及びその製造法を提供するものである。
【０００６】
【課題を解決するための手段】
４，４'−ジアミノアゾベンゼンや２，４−ジアミノアゾベンゼンのように、アゾベンゼンのベンゼン環上に直接アミノ基をもつ化合物は、電子吸引性のアゾ基とアミノ基との共役による（アミノ基の）反応性低下が起こりやすいので、これをモノマ原料として使用した場合に重合体の高分子量化は望みにくい。また、二つのアミノ基が互いに共役している場合、一つのアミノ基が反応すると他方のアミノ基の反応性は更に低下しやすいので、この場合も重合体の高分子量化は望みにくい。そこで、高分子原料としてのアゾ基含有ジアミンとしては、アゾ基とアミノ基が共役しておらず、かつ、２つのアミノ基どうしも互いに共役していないジアミンが必要となる訳である。
【０００７】
また、アゾ基のシス・トランス異性化やジアミンの非対称性（非線形材料として必要な条件）の利用も考え合わせると、前記式（１）とは異なる構造のアゾ基含有芳香族ジアミンの調製・入手が必要となる。本発明は、上述したような考察及び必要性に基づいてなされたものである。
【０００８】
すなわち、本発明は、式（７）又は、式（８）で表されるアゾ基含有芳香族化合物である。
【０００９】
【化５】

【００１０】
本発明は、また、式（５）
【００１１】
【化６】

［式中、Ａｒ¹及びＡｒ²は、ベンゼン環］で表される化合物と、式（６）
【００１２】
【化７】
Ｘ−Ａｒ^３−Ｙ （６）
［式中、Ｘはフッ素、塩素、臭素及びヨウ素から選ばれるハロゲン原子を示し、Ａｒ^３ はベンゼン環及びＹはニトロ基又はアミノ基を示す。］で表される化合物とをカップリングさせることを特徴とする、前記式（７）又は式（８）のアゾ基含有芳香族化合物の製造法にも関する。
【００１３】
また、本発明は、上記式（７）のアゾ基含有芳香族ジニトロ化合物を還元することを特徴とする、上記の式（８）のアゾ基含有芳香族ジアミン化合物の製造法にも関する。
【００１４】
【発明の実施の形態】
本発明のアゾ基含有芳香族ジニトロ化合物であって、芳香環がベンゼン環であるものは、次の式（７）で表される。
【００１５】
【化８】

【００１６】
式（７）で表される具体的化合物は、例えば、２，４−ビス（４−ニトロフェノキシ）アゾベンゼン、２，４−ビス（２−ニトロフェノキシ）アゾベンゼン、２，３−ビス（３−ニトロフェノキシ）アゾベンゼン、２，５−ビス（４−ニトロフェノキシ）アゾベンゼン、等である。
【００１７】
本発明のアゾ基含有芳香族ジアミンであって、芳香環がベンゼン環であるものは、次の式（８）で表される。
【００１８】
【化９】

【００１９】
式（８）で表される具体的化合物は、例えば、２，４−ビス（４−アミノフェノキシ）アゾベンゼン、２，４−ビス（２−アミノフェノキシ）アゾベンゼン、２，３−ビス（３−アミノフェノキシ）アゾベンゼン、２，５−ビス（４−アミノフェノキシ）アゾベンゼン、等である。
【００２０】
式（５）の化合物と式（６）の化合物のカップリング反応は、塩基の存在下に溶媒中で反応させて行なうことができる。ここで用いられる塩基としては、水素化ナトリウム、水素化カリウム、水素化カルシウム等の水素化金属、炭酸カリウム、炭酸ナトリウム等の金属炭酸塩、水酸化ナトリウム、水酸化カリウム等の金属水酸化物、ジイソプロピルエチルアミン、１，８−ジアザビシクロ［５，４，０］ウンデセン等のアミンがあり、溶媒としては、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−メチル−２−ピロリドン等のアミド系溶媒、ジエチルエーテル、ジイソプロピルエーテル、テトラヒドロフラン等のエーテル系溶媒、エタノール、メタノール等のアルコール系溶媒、ベンゼン、トルエン等の芳香族炭化水素系溶媒、ヘキサン、ヘプタン、シクロヘキサン、シクロヘプタン等のアルカン系溶媒などがある。他の反応条件については用いる試薬により異なるのでそれぞれ適当な条件を選ぶ。
【００２１】
式（７）のアゾ基含有芳香族ジニトロ化合物から式（８）のアゾ基含有芳香族ジアミンへの還元は、還元剤を用いて溶媒中で行なうことができる。還元剤としては水硫化ナトリウム、硫化ナトリウム、レゾルシン−炭酸ナトリウム、塩化スズ等があり、特に水硫化ナトリウムが好ましく用いられる。また水硫化ナトリウムを使用する場合は、例えば、Ｕｅｎｏの方法（Ａｍ．Ｓｏｃ．（１９５２），ｖｏｌ．７４，ｐ．４５０８）に準じて、式（７）のアゾ基含有芳香族ジニトロ化合物のエタノール溶液に水硫化ナトリウム水溶液を加え加熱すれば還元できる。
【００２２】
溶媒としては、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−メチル−２−ピロリドン等のアミド系溶媒、ジエチルエーテル、ジイソプロピルエーテル、テトラヒドロフラン等のエーテル系溶媒、エタノール、メタノール等のアルコール系溶媒、ベンゼン、トルエン等の芳香族炭化水素系溶媒、ヘキサン、ヘプタン、シクロヘキサン、シクロヘプタン等のアルカン系溶媒等が用いられ、更に好ましくは水と相溶するエタノール、メタノール等のアルコール系溶媒である。他の反応条件については用いる試薬により異なるのでそれぞれ適当な条件を選ぶ。
【００２３】
【実施例】
以下、実施例により本発明を具体的に説明する。
実施例１ ２，４−ビス（４−ニトロフェノキシ）アゾベンゼンの合成
【００２４】
【化１０】

【００２５】
温度計、還流冷却管を備えた三口フラスコに、水素化ナトリウム５．６ｇ（０．１４１ｍｏｌ）を量り取り、アルゴン雰囲気下で無水Ｎ，Ｎ−ジメチルホルムアミド１００ｍｌを加えた。これを撹拌下４℃に冷却し、２，４−ジヒドロキシアゾベンゼン１０ｇ（０．０４７ｍｏｌ）の無水Ｎ，Ｎ−ジメチルホルムアミド３５０ｍｌ溶液を３０分間かけて滴下した。この時、反応系を４〜５℃に保った。反応混合物を５０℃で１時間撹拌後、これを４０℃に冷却し、ｐ−フルオロニトロベンゼン１４．９ｍｌ（０．１４１ｍｏｌ）を滴下した。滴下終了後、５０℃で１．５時間、つづいて８０℃で１６時間撹拌した。反応混合物を大量の氷に注いで固体を析出させた後、これをセライトろ過し、ろ液はクロロホルムで抽出し、ろ滓はクロロホルムで洗浄した。クロロホルム抽出液と洗液とを合わせて、減圧濃縮した。残渣を酢酸エチル１５０ｍｌに溶解し、１Ｎ 塩酸（５０ｍｌ×１０回）にて洗浄した。有機層を無水硫酸マグネシウムにて乾燥後、減圧濃縮し、残渣をシリカゲルカラムクロマトグラフィー（ジエチルエーテル／ヘキサンの１：２（容量比）混合液）にて精製し、２，４−ビス（４−ニトロフェノキシ）アゾベンゼン８．８ｇを得た。
【００２６】
赤外吸収スペクトル（ＫＢｒ錠剤法） ν（ｃｍ^-1）：１５８２，１５０８，１４７８，１３３８，１２２４，１１６０，１０９８，９６８，８３８，７４２
ラマンスペクトル ν（ｃｍ^-1）：１５９９，１５８４，１４８６，１４６６，１４４５，１４２２，１３４１，１２４２，１２１３，１１７９，１１４８，１１１１，１００１，８６２
融点：８７℃
【００２７】
実施例２ ２，４−ビス（４−アミノフェノキシ）アゾベンゼンの合成
【００２８】
【化１１】

【００２９】
還流冷却管を備えたフラスコに、実施例１で得られた２，４−ビス（４−ニトロフェノキシ）アゾベンゼン０．５０ｇ（１．１０ｍｍｏｌ）を量り取り、エタノール２０ｍｌを加え、溶解した。これに５０ｗｔ％水硫化ナトリウム水溶液２０ｍｌを加え、８０℃で１０分間撹拌した。室温に冷却し、１Ｎ水酸化ナトリウム水溶液５０ｍｌを加えた後、酢酸エチル（５０ｍｌ×３回）で抽出した。有機層を無水硫酸マグネシウムにて乾燥後、減圧濃縮し、残渣をシリカゲルカラムクロマトグラフィー（メタノール／クロロホルムの１：１５（容量比）混合液）にて精製し、精製物（２，４−ビス（４−アミノフェノキシ）アゾベンゼン）０．２３ｇ（収率：５３％）を得た。
【００３０】
得られた前記精製物のうちの０．１２ｇをトルエン１ｍｌに８０℃オイルバス上で溶解し、室温に放置して析出した結晶をろ取した（１７．２ｍｇ）。また、これとは別に前記精製物のうちの０．１２ｇをトルエン１ｍｌに８０℃オイルバス上で溶解し、ヘキサン１０ｍｌに滴下して析出した固体をろ取した。室温にて１時間、６０℃にて１時間減圧乾燥し、茶色の固体６３．６ｍｇを得た。
【００３１】
前記結晶の理化学的性状は、以下の通り。
赤外吸収スペクトル（ＫＢｒ 錠剤法） ν（ｃｍ^-1）：３３２４，３０４４，１５８６，１４８０，１２１０，９６８，８０８，７４６
ラマンスペクトル ν（ｃｍ^-1）：１５９３，１４８３，１４６４，１４４１，１４１８，１３２６，１３１２，１２７２，１２４２，１１８１，１１４８，１０９８，１００１
融点：６７℃
【００３２】
【発明の効果】
請求項１のアゾ基含有芳香族化合物は新規な化合物である。請求項１の式（８）のアゾ基含有芳香族化合物は、その分子中のアゾ基とアミノ基が共役しておらず、かつ、分子中の２つのアミノ基どうしも互いに共役していない。また、ポリイミドやポリアミド等の高分子に組み込まれた場合、アゾ基は高分子の（主鎖骨格に組み込まれるのではなく）側鎖に組み込まれて存在するので、そのアゾ基のシス・トランス異性化を利用でき、光配向法を用いたラビングレス液晶配向膜の原料として有用である。また、これら化合物の構造は非対称性を有するので光導波路や波長変換素子等の非線形光学材料（ポリイミドやポリアミド）の原料として有用である。また、エポキシ樹脂等の硬化剤としても使用できる。請求項１の式（７）のアゾ基含有芳香族化合物は、請求項１の式（８）のアゾ基含有芳香族化合物の合成中間体として有用である。請求項２の製造法により、請求項１のアゾ基含有芳香族化合物を製造することができる。 [0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel azo group-containing aromatic compound and a production method, and more specifically, an azo group useful as a raw material for polyimide or polyamide used in nonlinear optical materials such as optical waveguides and wavelength conversion elements, liquid crystal alignment films, and the like. The present invention relates to an aromatic diamine containing azo group, an azo group-containing aromatic dinitro compound that is a synthetic intermediate thereof, and a production method thereof.
[0002]
[Prior art]
In recent years, azo-containing polymers containing azo groups in the polymer have advantages such as large nonlinear optical constants, various molecular structures, easy processing, and good mechanical strength. As a nonlinear optical material such as a wavelength conversion element or the like, it is attracting attention. However, many of the polymers reported so far have a skeleton having a relatively low glass transition temperature such as polystyrene or polymethacrylic acid (thus, there is a difficulty in heat resistance). In order to improve the glass transition temperature (and therefore heat resistance), first, a method of selecting polyimide or polyamide, which is a polymer having a high glass transition temperature, as a polymer skeleton can be considered.
[0003]
By the way, compounds having an amino group directly on the benzene ring of azobenzene, such as 4,4′-diaminoazobenzene and 2,4-diaminoazobenzene, have been known for a long time. Further, an azo group-containing aromatic diamine having no amino group directly on the benzene ring of azobenzene and having an aminophenoxy group as shown in the following formula (1) has been conventionally known. , 4′-diaminodiphenyl ether (US Pat. No. 3,644,328; C. Hartwig et al., Appl. Polym. Symp. (1973), No. 21, 35-42), or bis-allyl It has also been confirmed to be formed by the reaction of iminomagnesium and nitrobenzene (M.Okubo et al., J.Phys.Org.Chem. (1991), Vol.4, 693-700).
[0004]
[Formula 4]

[0005]
[Problems to be solved by the invention]
According to the above document, it is possible to synthesize a compound having one aminophenoxy group on both benzene rings of the two benzene rings of azobenzene as in formula (1). A compound having two aminophenoxy groups on one benzene ring cannot be synthesized. The present invention provides a compound having two aminophenoxy groups on one of the two benzene rings of azobenzene and a method for producing the same.
[0006]
[Means for Solving the Problems]
A compound having an amino group directly on the benzene ring of azobenzene, such as 4,4′-diaminoazobenzene or 2,4-diaminoazobenzene, is obtained by conjugation of an electron-withdrawing azo group and an amino group (of an amino group). Since the reactivity is likely to decrease, it is difficult to expect a high molecular weight polymer when used as a monomer raw material. In addition, when two amino groups are conjugated to each other, if one amino group reacts, the reactivity of the other amino group is likely to be further lowered, and in this case as well, it is difficult to increase the molecular weight of the polymer. Therefore, the azo group-containing diamine as a polymer material, an azo group and an amino group is not conjugated, and each other two amino groups also necessarily that Do required diamine not conjugated with each other.
[0007]
In addition, taking into account the use of cis / trans isomerization of azo groups and the asymmetry of diamines (required conditions for nonlinear materials), preparation and acquisition of azo group-containing aromatic diamines having structures different from those of formula (1) above Is required. The present invention has been made based on the above considerations and needs.
[0008]
That is, this invention is an azo group containing aromatic compound represented by Formula (7) or Formula (8).
[0009]
[Chemical formula 5 ]

[0010]
The present invention also provides formula (5)
[0011]
[Chemical 6 ]

[Wherein Ar ¹ and Ar ² are benzene rings ], and a formula (6)
[0012]
[Chemical 7 ]
^X-Ar 3 -Y (6)
[Wherein, X represents a halogen atom selected from fluorine, chlorine, bromine and iodine, Ar ³ represents a benzene ring, and Y represents a nitro group or an amino group . And a method for producing an azo group-containing aromatic compound represented by the formula (7) or (8) , wherein the compound represented by the formula (7) or (8) is coupled.
[0013]
The present invention also relates to a process for producing an azo group-containing aromatic diamine compound of the above formula (8), wherein the azo group-containing aromatic dinitro compound of the formula (7) is reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
A A zone group containing an aromatic dinitro compound of the present invention, those Fang incense ring is a benzene ring, represented by the following formula (7).
[0015]
[Chemical 8 ]

[0016]
Specific compounds represented by the formula (7) include, for example, 2,4-bis (4-nitrophenoxy) azobenzene, 2,4-bis (2-nitrophenoxy) azobenzene, 2,3-bis (3-nitro Phenoxy) azobenzene, 2,5-bis (4-nitrophenoxy) azobenzene, and the like.
[0017]
A A zone group-containing aromatic diamine of the present invention, those Fang incense ring is a benzene ring, represented by the following equation (8).
[0018]
[Chemical 9 ]

[0019]
Specific compounds represented by the formula (8) include, for example, 2,4-bis (4-aminophenoxy) azobenzene, 2,4-bis (2-aminophenoxy) azobenzene, 2,3-bis (3-amino) Phenoxy) azobenzene, 2,5-bis (4-aminophenoxy) azobenzene, and the like.
[0020]
The coupling reaction of the compound of formula (5) and the compound of formula (6) can be carried out by reacting in a solvent in the presence of a base. Examples of the base used here include metal hydrides such as sodium hydride, potassium hydride and calcium hydride, metal carbonates such as potassium carbonate and sodium carbonate, metal hydroxides such as sodium hydroxide and potassium hydroxide, There are amines such as diisopropylethylamine and 1,8-diazabicyclo [5,4,0] undecene, and solvents include amides such as N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone. Solvents, ether solvents such as diethyl ether, diisopropyl ether and tetrahydrofuran, alcohol solvents such as ethanol and methanol, aromatic hydrocarbon solvents such as benzene and toluene, alkane solvents such as hexane, heptane, cyclohexane and cycloheptane and so on. Other reaction conditions vary depending on the reagents used, and appropriate conditions are selected for each.
[0021]
Reduction of the azo group-containing aromatic dinitro compound of the formula (7) to the azo group-containing aromatic diamine of formula (8) can be carried out in a solvent using a reducing agent. Examples of the reducing agent include sodium hydrosulfide, sodium sulfide, resorcin-sodium carbonate, tin chloride, and sodium hydrosulfide is particularly preferably used. When sodium hydrosulfide is used, for example, according to the method of Ueno (Am. Soc. (1952), vol. 74, p. 4508), ethanol of an azo group-containing aromatic dinitro compound of the formula (7) The solution can be reduced by adding an aqueous sodium hydrosulfide solution and heating.
[0022]
Examples of the solvent include amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone, ether solvents such as diethyl ether, diisopropyl ether and tetrahydrofuran, and alcohols such as ethanol and methanol. Solvents, aromatic hydrocarbon solvents such as benzene and toluene, alkane solvents such as hexane, heptane, cyclohexane, and cycloheptane are used, and more preferably alcohol solvents such as ethanol and methanol that are compatible with water. is there. Other reaction conditions vary depending on the reagents used, and appropriate conditions are selected for each.
[0023]
【Example】
Hereinafter, the present invention will be described specifically by way of examples.
Example 1 Synthesis of 2,4-bis (4-nitrophenoxy) azobenzene
[Chemical formula 10 ]

[0025]
To a three-necked flask equipped with a thermometer and a reflux condenser, 5.6 g (0.141 mol) of sodium hydride was weighed, and 100 ml of anhydrous N, N-dimethylformamide was added under an argon atmosphere. This was cooled to 4 ° C. with stirring, and a solution of 10 g (0.047 mol) of 2,4-dihydroxyazobenzene in 350 ml of anhydrous N, N-dimethylformamide was added dropwise over 30 minutes. At this time, the reaction system was kept at 4-5 ° C. The reaction mixture was stirred at 50 ° C. for 1 hour, then cooled to 40 ° C., and 14.9 ml (0.141 mol) of p-fluoronitrobenzene was added dropwise. After completion of the dropping, the mixture was stirred at 50 ° C. for 1.5 hours and subsequently at 80 ° C. for 16 hours. The reaction mixture was poured into a large amount of ice to precipitate a solid, which was filtered through Celite, the filtrate was extracted with chloroform, and the filter cake was washed with chloroform. The chloroform extract and the washings were combined and concentrated under reduced pressure. The residue was dissolved in 150 ml of ethyl acetate and washed with 1N hydrochloric acid (50 ml × 10 times). The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (diethyl ether / hexane 1: 2 (volume ratio) mixture) to give 2,4-bis (4- 8.8 g of nitrophenoxy) azobenzene were obtained.
[0026]
Infrared absorption spectrum (KBr tablet method) ν (cm ⁻¹ ): 1582, 1508, 1478, 1338, 1224, 1160, 1098, 968, 838, 742
Raman spectrum ν (cm ⁻¹ ): 1599, 1584, 1486, 1466, 1445, 1422, 1341, 1242, 1213, 1179, 1148, 1111, 1001, 862
Melting point: 87 ° C
[0027]
Example 2 Synthesis of 2,4-bis (4-aminophenoxy) azobenzene
[Chemical Formula 11 ]

[0029]
To a flask equipped with a reflux condenser, 0.50 g (1.10 mmol) of 2,4-bis (4-nitrophenoxy) azobenzene obtained in Example 1 was weighed and dissolved by adding 20 ml of ethanol. To this, 20 ml of a 50 wt% aqueous sodium hydrosulfide solution was added and stirred at 80 ° C. for 10 minutes. After cooling to room temperature and adding 50 ml of 1N aqueous sodium hydroxide solution, the mixture was extracted with ethyl acetate (50 ml × 3 times). The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (methanol / chloroform 1:15 (volume ratio) mixture) to give a purified product (2,4-bis ( 0.23 g (yield: 53%) of 4-aminophenoxy) azobenzene) was obtained.
[0030]
0.12 g of the purified product thus obtained was dissolved in 1 ml of toluene on an oil bath at 80 ° C., and the crystals deposited after standing at room temperature were collected by filtration (17.2 mg). Separately from this, 0.12 g of the purified product was dissolved in 1 ml of toluene on an oil bath at 80 ° C. and dropped into 10 ml of hexane, and the precipitated solid was collected by filtration. The mixture was dried under reduced pressure at room temperature for 1 hour and at 60 ° C. for 1 hour to obtain 63.6 mg of a brown solid.
[0031]
The physicochemical properties of the crystal are as follows.
Infrared absorption spectrum (KBr tablet method) ν (cm ⁻¹ ): 3324, 3044, 1586, 1480, 1210, 968, 808, 746
Raman spectrum ν (cm ⁻¹ ): 1593, 1483, 1464, 1441, 1418, 1326, 1312, 1272, 1242, 1181, 1148, 1098, 1001
Melting point: 67 ° C
[0032]
【The invention's effect】
The azo group-containing aromatic compound of claim 1 is a novel compound. In the azo group-containing aromatic compound of the formula (8) of claim 1, the azo group and the amino group in the molecule are not conjugated, and the two amino groups in the molecule are not conjugated to each other. In addition, when incorporated into a polymer such as polyimide or polyamide, the azo group is incorporated in the side chain of the polymer (not incorporated into the main chain skeleton), so the cis-trans isomerism of the azo group is present. It is useful as a raw material for a rubbing-less liquid crystal alignment film using a photo-alignment method. In addition, since the structures of these compounds are asymmetric, they are useful as raw materials for nonlinear optical materials (polyimide and polyamide) such as optical waveguides and wavelength conversion elements. It can also be used as a curing agent such as an epoxy resin. The azo group-containing aromatic compound of the formula (7) of claim 1 is useful as a synthetic intermediate for the azo group-containing aromatic compound of the formula (8) of claim 1 . According to the production method of claim 2 , the azo group-containing aromatic compound of claim 1 can be produced .

Claims (3)

An azo group-containing aromatic compound represented by formula (7) or formula (8) .

Formula (5)

[Wherein Ar ¹ and Ar ² are benzene rings ], and a formula (6)

[Wherein, X represents a halogen atom, Ar ³ represents a benzene ring, and Y represents a nitro group or an amino group . ] The manufacturing method of the azo group containing aromatic compound of Claim 1 which couple | bonds with the compound represented by this. Reducing the azo group-containing aromatic dinitro compound of the formula according to claim 1 (7), the preparation of the azo group-containing aromatic diamine compound of formula (8) of claim 1.