JPH0920782A - Production of benzobisoxazolone derivative and intermediate therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a benzobisoxazolone derivative excellent in stability in its production, transport and preservation, and useful as a stock monomer for polybenzobisoxazole by reaction of a specific dinitroresorcin derivative with a halogenated alkyl carbonate followed by reducing the resultant compound and then heating the reduced compound. SOLUTION: A compound of formula I (R<1> and R<2> are each H or a halogen) is reacted with a halogenated alkyl carbonate in the presence of a base to produce a compound of formula II (R<2> is a 1-4C alkyl), which is, in turn, reduced through contact with hydrogen gas in the presence of e.g. a group VIII metal and copper as catalyst to form a compound of formula III, which is then heated e.g. at 180-250 deg.C to obtain the objective compound of formula IV.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the general formula [4]

[0002]

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(R ¹ and R ² represent a hydrogen atom or a halogen atom and may be the same or different) and are represented by benzo [1,2-d: 5,4-d '] bis-. 2 (3H)
-Method for producing oxazolone derivative and general formula [3] which is an intermediate thereof

[0004]

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(R ¹ and R ² are the same as defined above, and R ³ is an alkyl group having 1 to 4 carbon atoms)
The present invention relates to a bis (alkyl carbonate) -4,6-diaminobenzene derivative and a method for producing the same. This derivative is a compound useful as an intermediate for polymers, pharmaceuticals, agricultural chemicals, dyes and the like, and its application to polymers is important.

[0006]

2. Description of the Related Art In recent years, aromatic heterocyclic polymers have been researched and developed as next-generation high-performance materials. Among them, polybenzobisoxazole (PBO) is
It is a polymer developed at the request of the United States Air Force as the ultimate fiber that has superior performance to conventional aramid fibers in terms of strength, elastic modulus, heat resistance, etc. (Am. Che.
m. Soc. , Polym. Chem. , 16 (2),
559 (1975)).

Further, this PBO is obtained by polymerization of 4,6-diaminoresorcin and terephthalic acid (M
acromolecules 14 (4), 901-9
15 (1981) etc.). However, there are known methods for synthesizing 4,6-diaminoresorcin (EP26622).
No. 2, JP-A-2-229143, etc.),
Since 4,6-diaminoresorcin itself is extremely easily oxidized, it is difficult to purify it and it is difficult to obtain a large amount of high-purity polymer raw material.

On the other hand, various methods for synthesizing benzoxazolone are known, but as a simple method, O
-There is a method of synthesizing aminophenol and ethyl chloroformate in the presence of pyridine (JP-A-58-146569).
Publication, European patent 86126). But 1,3
-Bis (alkyl carbonate) -4,6-diaminobenzene derivative as a starting material, benzo [1,2-d: 5,4-d '] bis-2 (3H) which is the object compound of the present invention
-There is no example of obtaining an oxazolone derivative.

[0009]

In order to stably and economically produce polybenzobisoxazole (hereinafter abbreviated as PBO) which is an excellent fiber, stability in the production, transportation and storage of a PBO monomer. There has been a strong demand in the industry for conversion. The present invention is manufactured under such circumstances,
The purpose of the present invention is to provide a raw material monomer of PBO which is excellent in stability during transportation and storage.

[0010]

The present invention has the general formula [1]

[0011]

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(R ¹ and R ² represent a hydrogen atom or a halogen atom and may be the same or different), and a 4,6-dinitroresorcin derivative (abbreviated as DNR) represented by Reacting with an alkyl halide carbonate in the presence of the general formula [2]

[0013]

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(R ¹ and R ² are the same as defined above, and R ³ is an alkyl group having 1 to 4 carbon atoms)
A bis (alkyl carbonate) -4,6-dinitrobenzene derivative (abbreviated as BCNB) is obtained, and then BCNB
To reduce general formula [3]

[0015]

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(R ¹ , R ² and R ³ are the same as above.)
1,3-bis (alkyl carbonate)-
A 4,6-diaminobenzene derivative (abbreviated as BCAB) is obtained, and BCAB is further heated. [4]

[0017]

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Benzo [1,2-d: 5,4-d '] bis-2 (3 represented by (R ¹ and R ² are the same as above)
H) -Oxazolone derivative (abbreviated as BBO). In addition, the intermediate BCAB is a novel compound. Hereinafter, the present invention will be described in detail.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION First, as the DNR of the raw material used in the first step, 1,3-dichlorobenzene, 1,
4,6-dinitroresorcinol derived from 2,3-trichlorobenzene and resorcin, 2-chloro-4,
Examples thereof include 6-dinitroresorcin, 2-bromo-4,6-dinitroresorcin, 2,5-dichloro-4,6-dinitroresorcin, and 2,5-dibromo-4,6-dinitroresorcin.

Examples of the alkyl halide carbonate include methyl chloroformate, ethyl chloroformate, propyl chloroformate, butyl chloroformate and the like. As the base, hydroxides, carbonates, alcoholates and single substances thereof such as alkali metals and alkaline earth metals can be used, and among them, sodium methoxide and sodium ethoxide are preferable. The amount used is preferably 2 to 4 equivalents, particularly preferably 2 to 3 equivalents based on the DNR of the raw material. Is preferred.

As the solvent, tetrahydrofuran, 1,
2-dimethoxyethane, acetonitrile, N, N-dimethylformamide (DMF) and the like can be mentioned. The amount used is 1 to 50 times the DNR of the raw material, especially 1
It is preferably about 20 times by weight. The reaction temperature may be in the range of 0 ° C to the boiling point of the solvent, and the temperature range of 0 to 100 ° C is particularly preferable. After the reaction, the solvent is distilled off, hydrochloric acid water and ethyl acetate are added, the ethyl acetate layer is concentrated, and then recrystallized from toluene or the like to give a 1,3-bis (alkyl carbonate) -4,6-dinitrobenzene derivative. (BCN
B) is obtained.

Next, various reducing methods can be applied to the second step. Among them, the industrially preferable method is a catalytic reduction method using hydrogen gas. As the catalyst, copper and Group 8 metals such as nickel, cobalt, palladium, ruthenium, rhodium and platinum are used. The usage form is
It can be used alone or supported on carbon, silica, alumina and zeolite. The amount used is BCNB as raw material
On the other hand, as a metal, it is 0.01 to 1.0% by weight, and particularly 0.1.
The range of 05 to 0.5% by weight is preferable. The hydrogen pressure is in the range of atmospheric pressure to 50 kg / cm ² , particularly atmospheric pressure to 30 kg / c.
A range of m ² is preferred.

Solvents include alcohols such as methanol and ethanol, ethers such as dioxane and 1,2-dimethoxyethane, and N, N-dimethylformamide and N, N.
-Amids such as dimethylacetamide can be used.
The reaction temperature is in the range of 0 to 150 ° C., particularly 20 to 100.
It is preferably carried out in the range of ° C. After the reaction, after distilling off the solvent,
After adding DMF to the residue to dissolve the product, the catalyst is separated and concentrated to obtain crude crystals. By recrystallizing this with methanol, the target 1,3-bis (alkyl carbonate) -4,6-diaminobenzene derivative (BC
AB) is obtained.

The third step is BCA in the absence of solvent or in the solvent.
By heating B at 180 ° C. to 250 ° C., crystals of crude benzo [1,2-d: 5,4-d ′] bis-2 (3H) -oxazolone derivative (BBO) are obtained. As the solvent, 1-methyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be used under normal pressure or increased pressure. The amount used is 1 to 1 for the raw material BCAB.
50 times by weight, particularly 1 to 20 times by weight is preferable. After the reaction, the obtained crystals are recrystallized with DMF, washed with methanol and dried to obtain the desired BBO.

Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto.

[0026]

【Example】

Example 1 (Synthesis of 1,3-bis (ethyl carbonate) -4,6-dinitrobenzene)

[0027]

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6.0 g of 4,6-dinitroresorcinol
A mixed solution of (0.03 mol) and 40 ml of tetrahydrofuran was cooled to 5 ° C., and 4.86 g (0.09 mol) of sodium methoxide was added little by little to it, and the subsequent 1
Stirring was performed for hours. Then 8.46 g of ethyl chloroformate
Was added dropwise over 30 minutes. Then, after returning to room temperature, the mixture was slowly heated, and stirring was continued at about 50 ° C. for 6 hours to complete the reaction. After the reaction, tetrahydrofuran was distilled off, and the obtained residue was dispersed in dilute aqueous hydrochloric acid solution and ethyl acetate. The ethyl acetate layer was separated, dehydrated with sodium sulfate, concentrated and dried to obtain 10.4 g of crude crystals. Then, this crude crystal 10.
After adding 50 ml of toluene to 4 g and heating to 80 ° C. to remove insoluble matter by filtration, the filtrate was concentrated to about half amount and further cooled to precipitate crystals. The crystals were collected by filtration and dried to give a single-peak yellow crystal in liquid chromatography (8.44 g).
(0.025 mol, yield 82%) was obtained. The crystals were analyzed by MASS, ¹ H-NMR and ¹³ C-NMR and found to be the target 1,3-bis (ethyl carbonate) -4,6-dinitrobenzene.

Example 2 (Synthesis of 1,3-bis (ethyl carbonate) -4,6-diaminobenzene)

[0030]

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1,3-bis (ethyl carbonate)-
6,6-dinitrobenzene 6.86g (0.02mo
1), 30 g of ethanol and 0.29 g of 5% Pd / C (52% water content) were charged into a Hastelloy 100 ml autoclave, and the hydrogen pressure was 20 kg / cm ² constant pressure and room temperature (2
The reaction was started at 5 ° C. Immediately, exothermic hydrogen absorption was observed, and the temperature reached 40 ° C in about 30 minutes. After that, the fever calmed down, but hydrogen absorption continued, so put it in the bath for 50
When stirring was continued for 1 hour and 30 minutes while maintaining the temperature at 0 ° C., hydrogen absorption stopped.

After completion of the reaction, hydrogen gas in the autoclave was released, the slurry-like reaction product was taken out, and the solvent was distilled off. When N, N-dimethylformamide (DMF) was added to and dissolved in the obtained concentrate, Pd / C of the catalyst was precipitated. After filtering this off, DMF was distilled off to obtain 5.52 of crude crystals.
g was obtained. Methanol was added to 5.52 g of the crude crystals, and the mixture was once heated, cooled, filtered, and dried to give crystals 4.9.
4 g (0.017 mol, 87% yield) was obtained.

The crystals were analyzed by liquid chromatography and found to have a single peak. Further analysis results are shown below. MASS (m / e (%)): 284 (M ⁺ , 100) ¹ H-NMR (d ₆ -DMSO, ppm): 1.23
(T, 6H, J = 7.1 Hz, CH ₃ ), 4.09
(C, 4H, J = 7.1 Hz, CH ₂ ), 6.41
(S, 1 H _arom , 7.50-7.65 (br.s, 1 H
_arom ), 7.82-7.98 (br.s, 2H, N
H ₂ ), 9.08-9.28 (br.s, 2H, N
^{_{H 2) 13 C-NMR (}} d 6 -DMSO, ppm): 14.5
6, 39.13, 39.29, 39.46, 39.6
3,39.79, 39.96, 40.13, 60.0
6, 78.54, 78.81, 79.07, 103.1
9,116.98,154.21 From the above, this crystal was found to be 1,3-bis (ethyl carbonate) -4,6-diaminobenzene.

Example 3 (Benzo [1,2-d: 5,4-d '] bis-2 (3
H) -Synthesis of oxazolone)

[0035]

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1,3-bis (ethyl carbonate)-
2.84 g of 4,6-diaminobenzene (0.01 mo
1) is put into a reaction flask and put under a nitrogen atmosphere at 200-23.
Stirred at 0 ° C. for 2 hours. After the reaction, 5 g of N, N-dimethylformamide (DMF) was added, and the mixture was heated and dissolved, and cooled with ice. The precipitated crystal was separated by filtration, washed with methanol, and further dried. The crystals obtained were 1.61 g of needle crystals showing a single peak in liquid chromatography.

This crystal shows MASS, ¹ H-NMR, ¹³
From the C-NMR analysis, the desired benzo [1,2-d:
5,4-d '] bis-2 (3H) -oxazolone (BB
O). The BBO yield was 84%.

[Brief description of drawings]

FIG. 1 ¹ H-NM of 1,3-bis (ethyl carbonate) -4,6-diaminobenzene obtained in Example 2.
Chart by R.

FIG. 2 ¹³ C-NM of 1,3-bis (ethyl carbonate) -4,6-diaminobenzene obtained in Example 2.
Chart by R.

FIG. 3 is a MASS chart of 1,3-bis (ethyl carbonate) -4,6-diaminobenzene obtained in Example 2.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07C 213/02 C07C 213/02 219/34 219/34

Claims (6)

[Claims] 1. A compound of the general formula [1] (R ¹ and R ² represent a hydrogen atom or a halogen atom,
It may be the same or different. ) Is reacted with an alkyl halide carbonate in the presence of a base to give a compound of the general formula [2] (R ¹ and R ² are the same as above, and R ³ is an alkyl group having 1 to 4 carbon atoms.), To obtain a 1,3-bis (alkyl carbonate) -4,6-dinitrobenzene derivative. Then, the dinitrobenzene derivative represented by the general formula [2] is reduced to give the general formula [3] (R ¹ , R ² and R ³ are the same as above) to obtain a 1,3-bis (alkyl carbonate) -4,6-diaminobenzene derivative represented by the formula: General formula [4] characterized by heating a benzene derivative A method for producing a benzo [1,2-d: 5,4-d '] bis-2 (3H) -oxazolone derivative represented by (R ¹ and R ² are the same as above). 2. A general formula [2]: (R ¹ and R ² represent a hydrogen atom or a halogen atom,
R ³ may be the same or different and R ³ represents an alkyl group having 1 to 4 carbon atoms. 1,3-bis (alkyl carbonate) -4,6-dinitrobenzene represented by the formula (3) is reduced to give a compound represented by the general formula [3]: (R ¹ and R ² are the same as above, and R ³ is an alkyl group having 1 to 4 carbon atoms.) 1,3-bis (alkyl carbonate) -4,6-diaminobenzene and a salt thereof. And further heating the diaminobenzene derivative of the general formula [3]. A method for producing a benzo [1,2-d: 5,4-d '] bis-2 (3H) -oxazolone derivative represented by (R ¹ and R ² are the same as above). 3. The benzo [1,2-d: 5,4-d '] according to claim 1 or 2, wherein the reduction is catalytic reduction with hydrogen gas using a Group 8 metal and copper as a catalyst. Screw-
A method for producing a 2 (3H) -oxazolone derivative. 4. A general formula [3]: (R ¹ and R ² are the same as above, and R ³ is an alkyl group having 1 to 4 carbon atoms.) 1,3-bis (alkyl carbonate) -4,6-diaminobenzene and a salt thereof. . 5. A compound represented by the general formula [1]: (R ¹ and R ² represent a hydrogen atom or a halogen atom,
It may be the same or different. ) Is reacted with an alkyl halide carbonate in the presence of a base to give a compound of the general formula [2] (R ¹ and R ² are the same as above, and R ³ is an alkyl group having 1 to 4 carbon atoms.), To obtain a 1,3-bis (alkyl carbonate) -4,6-dinitrobenzene derivative. Next, the dinitrobenzene derivative represented by the general formula [2] is reduced to give the general formula [3] (R ¹ , R ² and R ³ are the same as above), 1,3-bis (alkyl carbonate)-
Process for producing 4,6-diaminobenzene and salts thereof. 6. The 1,3-bis (alkyl carbonate) -4,6-diaminobenzene and its salt according to claim 5, wherein the reduction is catalytic reduction with hydrogen gas using a Group 8 metal and copper as a catalyst. Manufacturing method.