JP3496081B2 - Oxadiazole compound and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel oxadiazole compound which is useful as a fluorescent whitening agent or as a material for organic electroluminescent devices, especially as an electron transport material, and a method for producing the same.

[0002]

Various oxadiazole compounds are known as materials for organic electroluminescence devices. For example, the Chemical Society of Japan, 1991, (11), p. 1540-154
8 describes an example using an oxadiazole compound as a light emitting material and an electron transporting material. Further, JP-A-3-205479, JP-A-4-212286, JP-A-4-363891, and JP-A-4-363.
Japanese Patent No. 894 also describes an example using an oxadiazole compound. However, there is still a problem with the stability of the thin film, and a high-luminance, high-reliability organic electroluminescent device has not been obtained yet.

[0003]

The present invention has a stable film-forming property as a material for an organic electroluminescence device, and is particularly useful as a light-emitting material, an electron-transporting material, and the like, and is denatured even after long-term storage. It is an object of the present invention to provide a novel oxadiazole compound that is difficult to produce and a method for producing the same.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an oxadiazole compound having a specific structure is effective, and have completed the present invention. I arrived. That is, according to the present invention, an oxadiazole compound represented by the following general formula (I) (Formula 1) is provided.

[Chemical 1] (In the formula, A represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group, which may be the same or different. R is a hydrogen atom or halogen. An atom, a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted alkoxy group or hydroxyl group. ) Also, the following general formula (II) (Chemical formula 2)

[Chemical 2] (In the formula, R represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a hydroxyl group. X represents a halogen atom.) , The following general formula (II
I) (formula 3) or general formula (IV) (formula 4)

[Chemical 3]

[Chemical 4] (In the formula, A represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group, respectively.)
There is provided a method for producing an oxadiazole compound, which comprises reacting with a tetrazole compound represented by the formula (1) to produce the oxadiazole compound represented by the general formula (1).

In the general formula (I), specific examples of the aromatic hydrocarbon group or aromatic heterocyclic group for A include styryl, phenyl, biphenyl, terphenyl,
Naphthyl, anthryl, acenaphthenyl, fluorenyl, phenanthryl, indenyl, pyrenyl, pyridyl, pyrimidyl, furanyl, pyronyl, thiophenyl,
Examples thereof include quinolyl, benzofuranyl, benzothiophenyl, indolyl, carbazolyl, benzoxazolyl, quinoxalyl, benzimidazolyl, pyrazolyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl and oxadiazolyl groups.

These aromatic hydrocarbon groups or aromatic heterocyclic groups are further one or more of a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, a trifluoromethyl group, a carbon number of 1 to 12, and preferably 1 To 6 alkyl groups, 1 to 12 carbon atoms, preferably 1 to 6 alkoxy groups,
It may have a substituent such as an aryloxy group, a phenyl group, a styryl group, a naphthyl group, a thiophenyl group, an aralkyl group, a biphenyl group, a bithiophenyl group, a furanyl group, a bifuranyl group, a pyronyl group or a bipyronyl group.

In the general formula (I), examples of the substituted or unsubstituted alkyl group for R include an alkyl group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms,
Examples of the substituent include a halogen atom, a hydroxyl group, a phenyl group, an alkoxy group, an amino group and the like. The substituted or unsubstituted alkoxy group has 1 to 1 carbon atoms.
2, preferably 1 to 6 alkoxy groups are mentioned, and the substituents thereof include halogen atom, hydroxyl group, amino group and the like.

The oxadiazole compound of the present invention represented by the general formula (I) has the following general formula (II) as described above.
(Chemical formula 2)

[Chemical 2] (Wherein R and X are the same as above), the acid halide compound represented by the following general formula (III) (Chemical formula 3) or general formula (IV) (Chemical formula 4)

[Chemical 3]

[Chemical 4] (In the formula, A is the same as the above.) It is obtained by reacting with a tetrazole compound.

The acid halide compound represented by the general formula (II) (formula 2) is represented by the following general formula (V) (formula 5)

[Chemical 5] (In the formula, R is the same as above.) It is synthesized by treating the carboxylic acid compound with a halogenating agent such as thionyl chloride, phosphorus pentachloride, phosgene, and aluminum chloride.

General formula (III) (formula 3) and general formula (IV)
The tetrazole compound of (Chemical Formula 4) is in a tautomeric relationship and is liable to change with each other, and it is difficult to take them out separately. Generally, both are mixed, and also in the present invention. You can use the one that you made. The tetrazole compound represented by the general formula (III) (Chemical formula 3) and the general formula (IV) (Chemical formula 4) used here is produced by a conventionally known method. For example, it can be synthesized by the method described in Synthesis 71 (1973).

The acid halide represented by the general formula (II) (formula 2) and the general formula (III) (formula 3) and the general formula (IV)
The reaction with the tetrazole compound represented by (Chemical Formula 4) is described in R.
It is performed according to the oxadiazole synthesis method of D. Huisgen et al. For example, Angew. Chem., 72, 366 (1960),
Chem.Ber. , 93, 2106 (1960), Tetrahedro
n, 11, 241 (1960), Chem. Ber., 98, 29
66 (1965) can be applied.

The reaction is a reaction between a tetrazole group and a carbonyl halide group. The compound represented by the general formula (II) (chemical formula 2) and the general formula (III) (chemical formula 3) and the general formula (IV)
The oxadiazole compound represented by the general formula (I) (chemical formula 1) can also be synthesized from a raw material in which the functional group of the compound represented by the chemical formula (4) is exchanged. That is, the reaction of the tetrazole compound represented by the following general formula (VI) (chemical formula 6) with the general formula (VII)
The oxadiazole compound represented by (Chemical Formula 1) can be synthesized.

[Chemical 6] (In the formula, the tetrazole group may include a tautomeric isomer.
Yes. R is the same as above. )

[Chemical 7]         A-COX ... (VII) (In the formula, A is the same as above. X represents a halogen atom.)

The oxadiazole compound represented by the general formula (I) (Formula 1) can also be synthesized by the following reaction. That is, the following general formula (II)

[Chemical 2] (Wherein R and X are the same as above), and a compound of the following general formula (VIII)

Embedded image A-CONHNH ₂ ... (VIII) (wherein A is the same as above) is reacted to give a compound represented by the following general formula (IX) (Chemical formula 9)

[Chemical 9] (Wherein A and R are the same as above), and a dehydration reaction is carried out to produce the oxadiazole compound represented by the general formula (I) (Formula 1). can do.

Furthermore, the oxadiazole compound represented by the general formula (I) (formula 1) has the following general formula (VII) (formula 7)

Embedded image A-COX ... (VII) (wherein A and X are the same as defined above),
The following general formula (X) (Chemical formula 10)

[Chemical 10] (In the formula, R is the same as above.) To produce a compound represented by the general formula (IX) (Chemical Formula 9), and further dehydration reaction The oxadiazole compound represented by the general formula (I) (Formula 1) can be produced.

General formula (X) used as a starting material
The compound represented by the chemical formula 10 is represented by the following general formula (XI)
1)

[Chemical 11] (In the formula, R is the same as above, and R'represents an alkyl group.)
It can be easily produced by the reaction of the ester derivative represented by and hydrazine.

The above-mentioned two synthetic steps of the compound represented by the general formula (IX) (formula 9) are usually carried out in the presence of a basic catalyst. Examples of the basic catalyst include pyridine and its derivatives, organic bases such as triethylamine, tributylamine, triethanolamine, quinoline, piperazine and morpholine, or inorganic bases such as sodium hydroxide, potassium hydroxide and sodium carbonate. Particularly, an organic basic catalyst is preferable. As the reaction solvent in this step, any solvent can be used as long as it can dissolve the compound represented by the general formula (IX) (Chemical Formula 9) even a little, but alcohol solvents such as ethanol and butanol, dioxane, Ether-based solvents such as tetrahydrofuran, aromatic solvents such as benzene, toluene, chlorobenzene and nitrobenzene, N, N-dimethylformamide, dimethyl sulfoxide and the like are preferable. Further, an organic basic catalyst such as pyridine described above may be used in excess and used as a solvent.

In the step of dehydrating the compound represented by the general formula (IX) (Chemical Formula 9) to perform ring closure, a dehydrating agent such as phosphorus oxychloride, thionyl chloride, polyphosphoric acid, boric acid or toluenesulfonic acid is used. In the presence of. As the reaction solvent at this time, the solvent shown in the above step can be used, but aromatic solvents such as chlorobenzene, dichlorobenzene, xylene and nitrobenzene, halogen solvents such as trichloroethane and trichloromethane are particularly preferable. The amount of the dehydrating agent used is 1 mol to 1 mol based on 1 mol of the starting material compound.
About 0 mol is appropriate, but for example, phosphorus oxychloride may be used in a large excess and used as a solvent. Usually, the reaction is 50
Completed within a few minutes to 10 hours at a temperature of 300 ° C to 300 ° C.

Table 1 shows specific examples of the oxadiazole compound represented by the general formula (I) (Formula 1) according to the present invention.

[0019]

[Table 1- (1)]

[0020]

[Table 1- (2)]

[0021]

[Table 1- (3)]

The oxadiazole compound represented by the general formula (I) of the present invention is particularly excellent as a constituent component of an organic electroluminescent device. For example, a thin film is formed by a vacuum deposition method, a solution coating method or the like, and an anode and a cathode are formed. The element can be obtained by directly or indirectly sandwiching with.

[0023]

EXAMPLES The present invention will now be described in more detail based on examples. The present invention is not limited to these examples.

Synthesis Example 1 Synthesis of a compound represented by the following structural formula (Formula 12) [general formula (II), R = H]

[Chemical 12] 11 g of pyromellitic dianhydride, 23 g of phosphorus pentachloride and 9 ml of phosphorus oxychloride were heated to reflux in the reaction vessel for about 16 hours to complete the reaction. About 27g by distillation from the reaction solution
After removing phosphorus oxychloride, the product was distilled under reduced pressure to obtain 15.34 g of the desired product (yield 93.5%). The melting point of this compound was 66.5 to 68.5 ° C. When the infrared absorption spectrum was measured by the KBr tablet method, it was 17
Absorption of CO stretching vibration derived from carbonyl chloride group was observed at 90 cm ^-1 and 1740 cm ^-1 .

Synthesis Example 2 Synthesis of a compound represented by the following structural formula (Formula 13) [general formula (III), A = biphenyl-
4-yl]

[Chemical 13] 20.0 g of p-cyanobiphenyl and sodium azide 7.9
8 g and ammonium chloride 6.57 g were put into a reaction vessel,
55 ml of N, N-dimethylformamide was added as a solvent, and the mixture was heated under reflux at 100 ° C to 110 ° C for 15 hours. After standing to cool, the reaction product was poured into 500 ml of water, filtered, and washed with water 500
It was washed with water to give 24.0 g of a crude product (yield 96.8).
%) Was obtained. This was recrystallized with 650 ml of dioxane to obtain 9.94 g (yield 40.1%) of a white powder. The decomposition point of this compound is 239.5 ° C to 240.3 ° C.
Met. Infrared absorption spectrum is 3200 cm ^-1 ~
A broad peak attributable to N—H stretching vibration of tetrazole was observed over 2500 cm ^−1, and it was confirmed to be a target compound.

Synthesis Example 3 Compound No. Synthesis of 26 [general formula (I), A = biphenyl-4-yl, R =
H] 1.0 g of the acid chloride compound obtained in Synthesis Example 1 and 3.48 g of the tetrazole compound obtained in Synthesis Example 2 were placed in a reaction vessel, 36 ml of pyridine dehydrated with molecular sieve as a solvent was added, and the mixture was heated under reflux for 30 hours. . After allowing to cool, 70 ml of methanol was added, the precipitate was filtered, and methanol 25
The product was washed with 0 ml to obtain 2.01 g of a crude product (yield: 68.8).
%) Was obtained. This is N, N-dimethylformamide 7
Recrystallization was performed in 60 ml to give 1.37 g (yield 46.9).
%) Pale yellow needle crystals were obtained. The melting point of this compound is 37
It was 2.8 ° C (DTA peak). The infrared absorption spectrum (KBr tablet method) is shown in FIG.

[0027]

[Table 1]

[0028] Application Example glass substrate size 2mm × 2mm on, thickness 17 0n m
Forming an anode of indium tin oxide (ITO), and having a hole transport layer of 40 nm composed of a diamine derivative represented by the following formula (XIV) (Chemical formula 14) and a diamine represented by the following formula (XV) (Chemical formula 15) Light emitting layer 15n made of a derivative
m, the compound No. 20n of electron transport layer composed of
m, an electron transport layer 3 represented by the following formula (XVI)
0 nm, MgAg electrode of 10: 1 atomic ratio 200 nm,
Each was formed by vacuum vapor deposition to produce an electroluminescent device.
The degree of vacuum during vapor deposition is 0.7 × 10 ⁻⁶ Torr, and the substrate temperature is room temperature. When a direct current power supply was connected to the anode and cathode of the device thus manufactured through a lead wire, the applied voltage was 1 at a current density of 425 mA / cm ² .
It was 7.2 V, and a clear green light emission was confirmed over a long period of time. In addition, it was confirmed that the device emitted light clearly even after storage for 3 months.

[Chemical 14]

[Chemical 15]

[Chemical 16]

Comparative Example The compound No. The following compound (XVII) instead of 26
An EL device was produced in the same manner as in Application Example 1 except that (Chemical Formula 17) was used. When a DC voltage was applied to this device, clear blue-green light emission was observed. However, no EL emission was observed after storage for 1 month.

[Chemical 17]

[0030]

EFFECTS OF THE INVENTION The oxadiazole compound of the present invention is a novel compound and can easily form a homogeneous transparent film by vapor deposition or the like, and also has an excellent function as an electron transport material for an organic electroluminescence device. Since it is provided and has little deterioration over time, it is useful as a highly reliable organic electroluminescent material. Further, the present invention can provide an advantageous method for producing the oxadiazole compound.

[Brief description of drawings]

1 is an oxadiazole compound of the present invention [in the general formula (I), A = 4-biphenyl-4-yl, R =
It is an infrared absorption spectrum figure (KBr tablet method) of [H].

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI (C07D 413/14 C07D 271: 10 271: 10 333: 10 333: 10) C07D 213: 16 (C07D 413/14 209: 32 213 : 16 C07D 215: 04 271: 10) 307: 79 (C07D 413/14 209: 32 271: 10) (C07D 413/14 215: 04 271: 10) (C07D 413/14 271: 10 307: 79) ( 56) References JP-A-4-363891 (JP, A) JP-A-6-136359 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C07D 271/10 CA (STN) REGISTRY (STN) CASREAT (STN)

Claims (2)

(57) [Claims] 1. An oxadiazole compound represented by the following general formula (I) (Formula 1). [Chemical 1] (In the formula, A represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group, which may be the same or different. R is a hydrogen atom or halogen. An atom, a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted alkoxy group or hydroxyl group, which may be the same or different. ) 2. The following general formula (II) (Chemical formula 2) (In the formula, R represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a hydroxyl group. X represents a halogen atom.) , The following general formula (II
I) (Chemical Formula 3) or general formula (IV) (Chemical Formula 4) [Chemical 4] (In the formula, A represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group, respectively.)
By reacting with a tetrazole compound represented by the following general formula (I) (In the formula, A represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group, which may be the same or different. R is a hydrogen atom or halogen. An atom, a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted alkoxy group or hydroxyl group, which may be the same or different. The manufacturing method of the oxadiazole compound characterized by manufacturing the oxadiazole compound represented by these.