JPH08193075A - Oxadiazole derivative and its production - Google Patents

Abstract

PURPOSE: To obtain a new oxadiazole derivative, having a high emission luminance and good electron transport and hole blocking properties, capable of forming a stable glassy state in a thin film for a long period and useful as an organic electroluminescent(EL) element or a fluorescent brightener. CONSTITUTION: This compound of formula I [Ar is a (substituted) alkyl, a (substituted) aryl or a (substituted) heterocyclic aromatic group], e.g. 2,3- bis[2-(biphenyl-4-yl)oxadiazol-5-yl]naphthalene. The compound of formula I is obtained by reacting a compound of formula II (X is a halogen) with a compound of formula III, reacting a compound of the formula ArCOX with a compound of formula IV, etc. The compound of formula IV is prepared by converting 2,3-dicyanonaphthalene as a raw material into a tetrazole.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel oxadiazole derivative and a method for producing the same, and more particularly to a novel compound useful as an organic EL device or a fluorescent whitening agent and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, various kinds of oxadiazole derivatives are known, and these are effectively used as a light emitting component or an electron transporting component of an organic EL device. For example, JP-A-3-205479 discloses an EL device using an oxadiazole derivative having an alkenyl group, a carbazolyl group or an aminophenyl group as a substituent as a light emitting component. However, these oxadiazole derivatives have problems in emission luminescence, electron transporting property and film forming property in a thin film.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a novel oxadiazole derivative having high emission brightness, good electron transporting property and stable film forming property in a thin film, which is useful as a constituent component of an organic EL device. The purpose is to provide.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a novel oxadiazole derivative having a specific structure is effective. That is, according to the present invention, an oxadiazole derivative represented by the following general formula (A) is provided.

Embedded image (In the formula, Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. )

In the Ar group in the above general formula (A), the alkyl group is a methyl group, an ethyl group, an n-propyl group, a tert-butyl group or the like, and the aryl group is a phenyl group, a biphenyl group or a naphthyl group. Group, phenanthryl group, fluorenyl group, indenyl group, pyrenyl group, styryl group and the like. Furthermore, examples of the heterocyclic aromatic ring include the following groups. Pyridyl group, pyrimidyl group, pyrazinyl group, triazinyl group, furanyl group, pyrrolyl group, thiophenyl group, quinolyl group,
Coumarinyl group, benzofuranyl group, benzimidazolyl group, benzoxazolyl group, dibenzofuranyl group, benzothiophenyl group, indolyl group, carbazolyl group, pyrazolyl group, imidazolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, indazolyl group, Benzothiazolyl group, pyridazinyl group, cinnolyl group, quinazolyl group, quinoxalyl group and the like.

Furthermore, these alkyl groups and aryls
Examples of the substituents on the group and the heterocyclic aromatic ring are as follows.
Is included. (1) Halogen atom, hydroxyl group, trifluoromethyl group,
Cyano group, nitro group. (2) Alkyl group; preferably C₁~ C₆, Especially C
₁~ C_FourIs a linear or branched alkyl group. (3) Aryl group; carbocyclic or heterocyclic aromatic ring
Yes, phenyl, naphthyl, anthryl, acenaphthenic
Le, fluorenyl, phenanthryl, indenyl, pyret
Nyl, pyridyl, pyrimidyl, furanyl, pyronyl, thiyl
Ophenyl, quinolyl, benzofuranyl, benazothiof
Phenyl, indolyl, carbazolyl, benzoxazoli
, Quinoxalyl, benzimidazolyl, pyrazolyl,
Dibenzofuranyl, dibenzothiophenyl, etc.
These aryl groups also include halogen atoms, hydroxyl groups, and cyano groups.
Group, nitro group, alkyl group, alkoxy group, amino group, etc.
May be replaced with. (4) Alkoxy group (-OR₁); R₁Is defined in (2)
Represents an alkyl group. (5) Aryloxy group; defined as the aryl group in (3)
The defined group is shown. (6) Alkylthio group (-SR₂); R₂Is defined in (2)
The group represented by Acyl such as alkyl group, acetyl group and benzoyl group
A group or an aryl group defined in (3),
R, such as piperidyl group and morpholyl group,₃And R_FourWhen
May form a ring together with the nitrogen atom. Also, Yuri
Form a ring in cooperation with a carbon atom on the aryl group, such as a dil group
May be done. (8) Alkoxycarbonyl group (-COOR_Five); R_FiveIs
Alkyl group defined in (2) or defined in (3)
Represents an aryl group. (9) Acyl group (-COR_Five), A sulfonyl group (-SO₂
R_Five), Carbamoyl group R_FourAnd R_FiveRepresents the meaning defined above. However,
R₃And R_FourIn collaboration with a carbon atom on the aryl group
Except when forming a ring. (10) Methylenedioxy group or methylenedithio group, etc.
An alkylenedioxy group or an alkylenedithio group. (11) Styryl group(R₆Represents a substituent defined in (1) to (10)
You. )

According to the present invention, the following production methods (I) to
There is provided a method for producing the oxadiazole derivative represented by the general formula (A) according to (IV).

Manufacturing method (I) The following general formula (B)

Embedded image (Wherein, X represents a halogen atom) and the following general formula (C)

Embedded image (Wherein Ar is the same as above) to react with the compound to produce the oxadiazole derivative represented by the general formula (A).

Production method (II) The following general formula (D)

Embedded image A compound represented by ArCOX (D) (wherein Ar is the same as above, X represents a halogen atom) and the following structural formula (E)

Embedded image The oxadiazole derivative represented by the general formula (A) is produced by reacting with the compound represented by.

Manufacturing method (III) The following structural formula (F)

[Chemical 6] The compound represented by the following general formula (G) is obtained by reacting the compound represented by

[Chemical 7] (However, Ar is the same as above.) (Step A-1) and a dehydration reaction (Step B-1) to produce a compound represented by the general formula (A). The oxadiazole derivative is prepared.

Process (IV) The compound represented by the general formula (B) and the following general formula (H)

Embedded image The compound represented by the general formula (G) is produced by reacting with a compound represented by Ar—CONHNH ₂ (H) (wherein Ar is the same as above) (step A- 2) Further, dehydration reaction is performed (step B-2) to produce the oxadiazole derivative represented by the general formula (A).

Each raw material compound used in these production methods (I) to (IV) will be described. First, the tetrazole compound represented by the general formula (C) is produced by a conventionally known method. For example, Synthesis71 (1
It can be synthesized by the method described in 973). The tetrazole compound represented by the structural formula (E) has the following structural formula (1)

[Chemical 9] It is manufactured by using the compound represented by as a raw material to form a tetrazole. As the method, for example, the method described in Synthesis (1973) is applied. The compound represented by the structural formula (F) used as a starting material is represented by the following general formula (J)

[Chemical 10] (However, R represents an alkyl group.) It can be easily produced by reacting an ester derivative represented by hydrazine. The compounds represented by the general formula (B) and the general formula (D) used as starting materials can be easily produced by treating the corresponding carboxylic acid with a halogenating agent such as thionyl chloride. it can.
The compound represented by the general formula (H) is a known compound and can be easily obtained.

Next, each step in the above manufacturing method will be described. The reaction of the compound represented by the general formula (B) with the compound represented by the general formula (C), and the reaction represented by the compound represented by the general formula (D) with the general formula (E) The reaction with the compounds represented is described by R.M. D. It is performed according to the oxadiazole synthesis method of Huisgen et al. For example, A
age. Chem. , 72, 366 (1060), C
hem. Ber. , 93, 2106 (1960), Te
trahedron, 11, 241 (1960), Ch
em. Ber. , 98, 2966 (1965).

Step (A-1) or (A-2)
Is usually performed 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, and inorganic bases such as sodium hydroxide, potassium hydroxide and sodium carbonate. However, an organic basic catalyst is particularly preferable. As the reaction solvent, any solvent can be used as long as it can dissolve the compound represented by the general formula (G) even a little, but alcohol solvents such as ethanol and butanol, ether solvents such as dioxane and tetrahydrofuran. Aromatic solvents such as benzene, toluene, chlorobenzene, and nitrobenzene, N, N-dimethylformamide, and dimethyl sulfoxide are preferable. Also,
Using an organic basic catalyst such as pyridine described above in excess,
It may be used as a solvent. The reaction is usually from room temperature to 150 ° C,
Complete in minutes to hours.

Further, the step (B-1) or (B-2)
In the dehydration step, dehydration ring closure is performed with a dehydrating agent such as phosphorus oxychloride, thionyl chloride, polyphosphoric acid, boric acid, and toluenesulfonic acid to obtain the oxadiazole derivative represented by the general formula (A). Is. As the reaction solvent at this time, the solvent shown in step (A-1, A-2) can be used, but aromatic solvents such as chlorobenzene, dichlorobenzene, xylene and nitrobenzene, halogen-based solvents such as trichloroethane and the like. A solvent and the like are particularly preferable. The amount of the dehydrating agent to be used is appropriately about 1 mol to 10 mol with respect to 1 mol of the compound represented by the general formula (G), but, for example, phosphorus oxychloride may be used in a large excess to serve as the solvent. The reaction is usually completed at several minutes to 10 hours at 50 to 300 ° C.

Next, Table 1 shows specific examples of the oxadiazole derivative represented by the general formula (A) according to the present invention.

[Table 1- (1)]

[0017]

[Table 1- (2)]

[0018]

The present invention will be described in more detail based on the following examples. Example 1 Synthesis of the following compound (K) [general formula (B): X = Cl]

[Chemical 11] 2,3-dicarboxyl naphthalene 4.32 g (0.0
(2 mol) in a reaction vessel, and phosphorus pentachloride (9.53 g)
(0.046 mol) and 5 ml of phosphorus oxychloride were heated and stirred at 140 ° C. for 17 hours under a nitrogen gas flow. After completion of the reaction, excess phosphorus oxychloride is removed by distillation, and further sufficiently dried at room temperature with an aspirator,
An orange solid was obtained (5.26 g, yield> 100).
%). The produced compound (K) was extremely reactive, and decomposition into an acid anhydride was observed when left in the air. Therefore, the reaction with tetrazole represented by the following structural formulas (L) and (N) was immediately performed.

Example 2 The following compound (L) [general formula (C): Ar = biphenyl]
Synthesis of

[Chemical 12] 20.0 g (0.11 mol) of p-cyanobiphenyl, 7.98 g (0.12 mol) of sodium azide and 6.57 g (0.12 mol) of ammonium chloride were placed in a reaction vessel, and N, N-dimethylformamide was used as a solvent. 55m
Then, the mixture was heated to reflux at 100 ° C to 110 ° C for 15 hours. After allowing to cool, the reaction product was poured into 500 ml of water, filtered, and washed with 500 ml of water to obtain 24.0 g of a crude product (yield 9
6.8%) 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 24
It was 0.3 ° C. Infrared absorption spectrum is 3200
cm toward ^{-1 ~2500cm -1} tetrazole N-H
Broad beak attributed to stretching vibration was observed, confirming that it was the target.

Example 3 Synthesis of oxadiazole represented by the following structural formula (M)

[Chemical 13] Acid chloride derivative (K) 0.48 obtained in Example 1
g (1.90 mmol) and 0.94 g (1.90 × 2 × 1.1 m) of the tetrazole derivative (L) obtained in Example 2.
was added to the reaction vessel, 50 ml of pyridine (dehydrated calcium hydride) was added as a solvent, and the mixture was heated under reflux for 18.5 hours. After allowing to cool, pour the reaction product into 1000 ml of water,
After sufficient precipitation, filtration was performed to obtain 1.32 g of a crude product (yield> 100%). Column chromatography (developing solvent methylene chloride: tetrahydrofuran = 5)
Purification was performed by 0: 1 (volume ratio), and further toluene / n-hexane = 110/50 ml.
Recrystallized to yield 330 mg of white powder (yield 3
0.6%) was obtained. Melting point: 216.0-217.0 ° C. An infrared absorption spectrum diagram (KBr tablet method) is shown in FIG. From the above, it was confirmed that the target product was obtained.

Example 4 Synthesis of oxadiazole represented by the following structural formula (N)

Embedded image Acid chloride derivative (K) 1.27 obtained in Example 1
g (5.0 mmol) and 2.16 g (5.0 × 2 × 1.1 mmol) of the tetrazole derivative (O) shown below were placed in a reaction vessel, and 50 ml of pyridine (dehydrated calcium hydride) was added as a solvent. Heated to reflux for hours. After allowing to cool, the reaction product was poured into 1000 ml of water for sufficient precipitation, and then filtered. This was subjected to column chromatography (developing solvent methylene chloride: tetrahydrofuran = 50: 1 (v
It was recrystallized twice with 135 ml and 100 ml of toluene to obtain 710 mg of white powder (yield 27.5%).

[Chemical 15] Melting point: 242.0-243.0 ° C. An infrared absorption spectrum diagram (KBr tablet method) is shown in FIG.

Application Example 1 (Application of organic EL device to electron injecting and transporting material) By ultrasonic cleaning with a neutral detergent and isopropyl alcohol in order,
Thoroughly washed ITO (indium tin oxide: film thickness 2
000Å) 400 Å of the following compound (P) as a hole injecting and transporting layer, 150 Å of the following compound (Q) as a light emitting layer, and an oxadiazole derivative (M) obtained in Example 3 as an electron injecting and transporting layer on a substrate. 150 Å, and further the following compound (R) 30 as a second electron injecting and transporting layer.
The layers were sequentially formed by vacuum deposition. Further, a mask was set on the substrate and a cathode of Mg: Ag = 10: 1 (vapor deposition rate ratio) was formed to 2000 liters to prepare an EL element of 2 mm × 2 mm square. The degree of vacuum during vapor deposition is 0.7 × 10 ^-7 torr
The substrate temperature was room temperature. When a direct current voltage was applied to the EL element thus produced through a lead wire, it was 352 cd / m ² at a current density of 30 mA / cm ² .
The emission brightness of was observed. The applied voltage at this time is 6.5.
It was 5V. The EL light emission peak was 467 nm, and blue light emission from the light emitting layer was observed. Since the EL emission coincides with the fluorescent component of the light emitting layer, the oxadiazole derivative (M) forming the electron injecting and transporting layer injects electrons into the light emitting layer, and conversely does not accept hole injection from the light emitting layer.
It can be seen that the oxadiazole derivative (M) has an electron transporting ability and a hole blocking effect. Also,
When the EL device thus produced was left at room temperature for 30 days and then driven again, no remarkable deterioration was observed.

Embedded image

[Chemical 17]

Embedded image

Application Example 2 (Application of organic EL device to electron injecting and transporting material) By ultrasonic cleaning in order with a neutral detergent and isopropyl alcohol,
Thoroughly washed ITO (indium tin oxide: film thickness 2
000Å) 400 Å of the compound (P) as a hole injecting and transporting layer, 150 Å of the compound (Q) as a light emitting layer, and an oxadiazole derivative (N) obtained in Example 4 as an electron injecting and transporting layer on a substrate. 150 Å, and further the compound (R) as a second electron injecting and transporting layer 30
The layers were sequentially formed by vacuum deposition. Further, a mask was set on the substrate and a cathode of Mg: Ag = 10: 1 (vapor deposition rate ratio) was formed to 2000 liters to prepare an EL element of 2 mm × 2 mm square. The degree of vacuum during vapor deposition is 0.7 × 10 ^-7 torr
The substrate temperature was room temperature. When a direct current voltage was applied to the EL element thus produced through a lead wire, it was 421 cd / m ² at a current density of 30 mA / cm ² .
The emission brightness of was observed. The applied voltage at this time is 7.3.
It was 5V. The EL emission peak was at 465 nm, and blue emission from the light emitting layer was observed. Since the EL emission coincides with the fluorescent component of the light emitting layer, the oxadiazole derivative (N) forming the electron injecting and transporting layer injects electrons into the light emitting layer, and conversely does not accept hole injection from the light emitting layer.
It can be seen that the oxadiazole derivative (N) has an electron transporting ability and a hole blocking effect. Also,
When the EL device thus produced was left at room temperature for 30 days and then driven again, no remarkable deterioration was observed.

[0024]

INDUSTRIAL APPLICABILITY The oxadiazole derivative represented by the general formula (A) of the present invention is novel, exhibits high luminous efficiency in an organic EL device, and is stable in a thin glass state for a long period of time. By being formed as described above, it is useful as a constituent component of an EL element. Further, according to the present invention, the novel oxadiazole derivative can be industrially produced advantageously.

[Brief description of drawings]

FIG. 1 is an infrared spectrum diagram (KBr tablet method) of an oxadiazole derivative (M) obtained in Example 3 of the present invention.

FIG. 2 is an infrared spectrum diagram (KBr tablet method) of the oxadiazole derivative (N) obtained in Example 4 of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07D 413/14 333 C09K 11/06 Z 9280-4H H05B 33/20 // (C07D 413/14 271 : 10 333: 10) (C07D 413/14 213: 16 271: 10) (C07D 413/14 209: 82 271: 10) (C07D 413/14 215: 06 271: 10) (C07D 413/14 271: 10 307: 79)

Claims (5)

[Claims] 1. The following general formula (A): (In the formula, Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. ) An oxadiazole derivative represented by: 2. The following general formula (B): (Wherein, X represents a halogen atom) and a compound represented by the following general formula (C): (In the formula, Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. ) The compound represented by the general formula (A) is produced by reacting the compound represented by the formula (1) with the compound represented by the formula (1). 3. The following general formula (D): embedded image ArCOX (D) (wherein Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. X represents a halogen atom. )
And a compound represented by the following structural formula (E): The method for producing an oxadiazole derivative according to claim 1, wherein the compound represented by the general formula (A) is produced by reacting the compound represented by 4. The following structural formula (F): And a compound represented by the general formula (D): ArCOX (D) (wherein Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. X represents a halogen atom. )
A compound represented by the following general formula (G): (In the formula, Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. ) The compound represented by the general formula (A) is produced by producing a compound represented by the formula (1) and further performing a dehydration reaction, to thereby produce the oxadiazole derivative according to claim 1. . 5. The following general formula (B): (Wherein, X represents a halogen atom) and a compound represented by the following general formula (H): Ar-CONHNH ₂ (H) (wherein Ar is a substituted or unsubstituted alkyl group) ,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. ) And a compound represented by the following general formula (G) (In the formula, Ar is a substituted or unsubstituted alkyl group,
It represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic aromatic ring. ) The compound represented by the general formula (A) is produced by producing a compound represented by the formula (1) and further performing a dehydration reaction, to thereby produce the oxadiazole derivative according to claim 1. .