GB2153347A - 1,3-bis(3-aminophenoxy)benzene derivatives and their preparation - Google Patents

Abstract

1,3-Bis(3-aminophenoxy)-5-bromobenzene and 1,3-bis(3-aminophenoxy)-5-chlorobenzene can be prepared by reacting a 1,3,5-trihalobenzene with 3-aminophenol, in the presence of a dehydrohalogenating agent such as an alkali metal hydroxide, carbonate, bicarbonate or alkoxide. <IMAGE>

Description

SPECIFICATION 1 ,3-bis(3-aminophenoxy)benzene derivatives and their preparation The present invention relates to 1,3-bis(3-amino-phenoxy)benzene derivatives and to their preparation.

1 ,3-Bis(3.aminophenoxy)benzene is known as a monomer for preparing heat-resistant polymers such as polyamides and polyimides. US-A-3845018 and US-A-3879349 describe the preparation of especially heat-resistant acetylene-terminated polyimides from 1,3-bis(3-aminophenoxy)benzene, 3,31,4,41-benzophenonetetracarboxylic dianhydride and 3-aminophenylacetylene.

Novel compounds according to the present invention are 1 ,3-bis(3-aminophenoxy)-5-bromo- benzene and 1 ,3-bis(3.aminophenoxy)-5-chlorobenzene. These compounds may be represented by formula I (see the end of the description) in which X is Br or Cl.

The novel compounds may be converted to 1,3-bis(3-aminophenoxy)benzene, e.g. as described and claimed in a British Patent Application to be filed in the name of Mitsui Toatsu Chemicals, Inc. on 16th August 1 984 and entitled "Process for preparing 1,3-bis(3-aminophe noxy)benzene" .

A process according to the invention, for preparing a novel compound according to the invention, comprises reacting a 1,3,5-trihalobenzene (in which each halogen atom is Br or Cl) with 3-aminophenol, in the presence of a dehydrohalogenating agent.

The new process involves the reaction of one molecule of the 1,3,5-trihaobenzene and two molecules of 3-aminophenol, in the presence of a dehydrohalogenating agent, in an organic solvent. Unlike an ordinary Ullmann reaction, no copper compound is necessary as an accelerator. The process according to the present invention also has the advantage that the condensation reaction proceeds easily under mild conditions, simply by removing water, to produce a 1 3-bis(3-aminophenoxy)-5-halobenzene in high yield.

The trihalobenzene which is used may be represented by formula II (see the end of the description), in which X1, X2 and X3 are each Br or Cl. Examples of such compounds are 1,3,5trichlorobenzene, 1 , 3-dichloro-5-bromobenzene, 1 , 3-dibromo-5-chlorobenzene and 1 , 3, 5-tribro- mobenzene.

When 1 ,3,5-trichlorobenzene or 1 ,3-dichloro-5-bromobenzene is used, the product is 1,3bis(3-aminophenoxy)-5-chlorobenzene. When 1, 3-dibromo-5-chlorobenzene is used, the main product is 1,3-bis(3-aminophenoxy)-5-chlorobenzene. When 1,3,5-tribromobenzene is used, the product is 1 ,3-bis(3-aminophenoxy)-5-bromobenzene.

The amount of 3-aminophenol used is from 2 to 5 mol, preferably from 2.1 to 3 mol, per mol of 1,3, 5-trihalogenobenzene used.

Examples of the dehydrohalogenating agents to be used include hydroxides, carbonates, bicarbonates and alkoxides of alkali metals. More particularly, they include potassium hydroxide, sodium hydroxide, lithium hydroxide, potassium carbonate, sodium carbonate, lithium carbonate, potassium bicarbonate, sodium bicarbonate, potassium ethoxide, potassium isopropoxide, sodium methoxide, sodium ethoxide, lithium ethoxide or the like. One or more of these dehydrohalogenating agents may be used.

The amount of the dehydrohalogenating agent used is at least an equivalent amount, preferably from 1 to 1.5 times the equivalent amount of 3-aminophenol used.

In a process according to the present invention, solvents may be used. Preferably aprotic polar solvents are used. Examples of such aprotic polar solvents include N-methylformamide, N,Ndimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, Nmethylpyrrolidone, 1 ,3-dimethyl-2-imidazolidinone and hexamethylphosphoric triamide. Though the amount of solvents used is not limited, it is generally from 1 to 10 times the weight of starting materials used.

In general, the reaction temperature is in the range of 1 20 to 240"C, the range of 1 40 to 220"C being preferred.

The process of the present invention can be carried out according to the following general procedure: a specified amount of 3-aminophenol, a dehydrohalogenating agent and a solvent are charged in a reaction vessel, the 3-aminophenol is converted into its alkali metal salt and then 1,3,5-trihalogenobenzene is added to the vessel to accomplish the condensation. Alternatively, the process of the present invention can be carried out according to another procedure: that is, 3-aminophenol, a dehydrohalogenating agent, a solvent and 1,3,5-trihalogenobenzene are charged simultaneously and the mixture is heated to accomplish the condensation.

When water generates in the reaction system, it can be gradually removed by passing gaseous nitrogen through the system. However, in general, it is removed from the reaction system by azeotropic distillation by the use of a small amount of benzene, toluene, xylene, chlorobenzene or the like. After the completion of the reaction, the reaction mixture is optionally concentrated, and the concentrated or unconcentrated reaction mixture is poured into water to give a crude product. The crude product can be purified by converting it into its mineral acid addition salt such as hydrochloride.

The end of the reaction can be determined by monitoring the reduction in the amount of an unreacted intermediate (e.g. a monoaminophenoxy compound) by thin-layer chromatography or high-performance liquid chromatography.

According to the procedure as described above, 1 ,3-bis(3-aminophenoxy)-5-chlorobenzene and 1,3-bis(3-aminophenoxy)-5-bromobenzene. which correspond to the compounds of the general formula (II) wherein X is a chlorine atom or a bromine atom, can be obtained.

The following examples are to further illustrate the compounds according to the present invention and the processes for their preparation.

Example 1 1 20 g (1.1 mol) of 3-aminophenol, 75 g (1.15 mol) of granular potassium hydroxide having a purity of 86%, 500 ml of 1,3-dimethyl-2-imidazolidinone (hereinafter referred to as "DM1") and 50 ml of xylene are charged in a 2 1 flask equipped with a stirrer and a water separator. The temperature of the content was raised under stirring while passing gaseous nitrogen through it, so that the xylene in the reaction system was refluxed to remove water formed in the system by a water separator. The amount of water distilled away was 20.5 ml.

A solution of 91 g (0.5 mol) of 1,3,5-trichlorobenzene in 250 ml of DMI was added to the flask over one hour. The resulting mixture was maintained at a temperature of from 1 45 to 1 50'C for 5 hours, while distilling away the xylene. Then, the mixture was heated to a temperature of 1 70 to 180"C and maintained at that temperature for 1 8 hours to accomplish the condensation.

Immediately after the completion of the reaction, the reaction mixture was distilled under a vacuum of 50 to 70 mmHg by an aspirator to recover 690 ml of DMI solvent. The residue was thrown into 1.5 1 of water under vigorous stirring. A brown oil layer was separated as a lower layer. The brown oil comprised crude 1,3-bis(3-aminophenoxy)-5-chlorobenzene having a purity of 92.3% (determined by high-performance liquid chromatography). The two-layer mixture was left standing and decanted to obtain the brown oil. 520 g (2.5 mol) of a 6N aqueous solutio of hydrochloric acid was added to the brown oil and the mixture was heated to form a solution.

The solution was left standing and cooled at an ambient temperature to precipitate 1,3-bis(3aminophenoxy)-5-chlorobenzene hydrochloride. The mixture was filtered. The resulting filter cake was washed with a 10% aqueous solution of sodium chloride and dried to obtain 174.4 g of 1,3-bis(3-aminophenoxy)-5-chlorobenzene hydrocloride (yield: 87.3%). This product was recrystallized from isopropanol containing 2% of water to obtain a pure white needle crystal.

(m.p. 268-272"C) Elemental analysis (C18H17N202Cl3) C H N Cl calculated (%) 54.09 4.29 7.01 26.61 observed (%) 53.92 4.34 7.0 26.59 Pure 1 ,3-bis(3-aminophenoxy)-5-chlorobenzene hydrochloride was dissolved in water and neutralized with a dilute aqueous solution of ammonia to liberate 1,3-bis(3-aminophenoxy)-5chlorobenzene as a slightly brown oil.

The liberated 1 ,3-bis(3-aminophenoxy)-5-chlorobenzene was extracted with ether and dried in vacuo to obtain a slightly brown oil as a product. The oil was stored in a cold place to obtain a crystal (m.p. 72-73"C).

Elemental analysis (C,8H,5N202CI) C H N CI calculated (%) 66.16 4.63 8.57 10.85 observed (%) 66.00 4.82 8.39 10.78 IR spectrum (KBr tablet) (cm-l) 3460, 3390, 1630, 1605, 1585, 1500, 1445, 1320, 1290, 1185, 1165, 1015, 1000.

Mass spectrum (M/e) M+ 326, 290, 217, 183 Example 2 120 g (1.1 mol) of 3-aminophenol, 59.5 g (1.1 mol) of sodium methoxide and 500 ml of Nmethylpyrrolidone were charged in the same apparatus as described in Example 1. The temperature of the content was raised under stirring while passing gaseous nitrogen through it.

When the internal temperature reached 67"C, methanol began to be distilled away. The temperature was raised slowly while distilling away methanol. When the internal temperature reached 120"C, 91 g (0.5 mol) of 1,3,5-trichlorobenzene were added. The amount of methanol distilled away was 38 ml. The content was heated to 1 70 to 180"C and maintained at that temperature for 1 5 hours to accomplish the condensation. Then the reaction mixture was treated according to the same procedure as described in Example 1 to obtain 1 70 g of 1,3-bis(3aminophenoxy)-5-chlorobenzene hydrochloride (yield: 85%).

Example 3 32.7 g (0.3 mol) of 3-aminophenol, 18.2 g (0.1 mol) of 1,3,5-trichlorobenzene, 28 g (0.2 mol) of anhydrous potassium carbonate and 1 50 ml of hexamethylphosphoric triamide were charged in a flask equipped with a stirrer. The mixture was maintained at 1 80 to 190to for 24 hours under stirring while passing gaseous nitrogen through it to accomplish the condensation.

Then the reaction mixture was treated according to the same procedure as described in Example 1 to obtain 34.4 g of 1,3bis(3-aminophenoxy)-5-chlorobenzene hydrochloride (yield: 85.8%).

Example 4 12 9 (0.11 mol) of 3-aminophenol, 4.6 9(0.1 mol) of granular potas'sium hydroxide of a purity of 96%, 10 ml of toluene and 50 ml of DMI were charged in the same apparatus as described in Example 1. The temperature of the content was raised under stirring while passing gaseous nitrogen through it, so that the toluene was refluxed to remove the water which generated in the reaction system by a water separator. 50 ml of DMI and 1 5.7 g (0.05 mol) of 1 ,3,5-tribromobenzene were added. The resulting mixture was maintained at 1 50 to 160"C for 20 hours to accomplish the condensation, while distilling away the toluene contained in the system.Then the reaction mixture was treated according to the same procedure as described in Example 1 to obtain 16.89 of 1,3-bis(3aminophenoxy)-5-bromobenzene hydrochloride (yield: 75.7%).

This product was recrystallized from isopropanol containing 2% of water to obtain a slightly brown needle crystal as a pure product (m.p. 273-277"C).

Elemental analysis (C18H17N2O2BrCl2) C H N Br Cl calculated (%) 48.67 3.86 6.31 17.99 15.97 observed (%) 48.57 3.92 6.21 17.73 15.9 The resulting pure 1 ,3-bis(3-aminophenoxy)-5.bromobenzene hydrochloride was dissolved in water and neutralized with a dilute aqueous solution of ammonia to liberate 1,3-bis(3aminophenoxy)-5-bromobenzene. The liberated 1, 3-bis(3-aminophenoxy)-5-bromobenzene was extracted with ether and dried in vacuo to obtain a slightly brown oil as a product. The oil was stored in a cold place to form a crystal (m.p. 68-69"C).

Elemental analysis (Cr8HasN202Br) C H N Br calculated (%) 58.24 4.07 7.55 21.53 observed (%) 58.09 4.18 7.48 21.45 IR spectrum (KBr tablet) (cm-l) 3460, 3340, 1625, 1605, 1585, 1500, 1460, 1320, 1290, 1185, 1165, 1015, 1000 Mass spectrum (M/e) M+ 370, 290, 154 Example 5 12 g (0.11 mol) of 3-aminophenol, 7.2 9(0.1 mol) of granular potasium hydroxide having a purity of 86%, 11.3g(0.05 mol) of 1-bromo-3,5-dichlorobenzene, 10 ml of benzene and 100 ml of N-methylpyrrolidone were charged in the same apparatus as described in Example 1. The temperature of the content was raised under stirring while passing gaseous nitrogen through it.

The internal temperature was raised to 120on, while azeotropically distilling away water along with the benzene. The content was maintained at that temperature for 5 hours. Then, the internal temperature was raised to 1 70 to 180"C and the content was maintained at that temperature for 1 2 hours to accomplish the condensation.

The reaction mixture was treated according to the same procedure as described in Example 1 to obtain 16.3 g of 1,3-bis(3-aminophenoxy)-5-chlorobenzene hydrochloride (yield: 81.5%).

This product was recrystallized from isopropanol containing 2% of water to obtain a white needle crystal (m.p. 267-268"C).

Elemental analysis (C,8H17N202CI3) C H N Cl calculated (%) 54.09 4.29 7.01 26.61 observed (%) 53.98 4.40 6.92 26.47 Example 6 12 g (0.11 mol) of 3-aminophenol, 13.5 g (0.05 mol) of 1,3-dibromo-5-chlorobenzene, 10.4 g (0.075 mol) of potassium carbonate and 100 mi of dimethyl sulfoxide were charged in a flask equipped with a stirrer. The content was heated to a temperature of 1 50 to 1 70'C and maintained at that temperature for 24 hours to accomplished the condensation.

The reaction mixture was treated according to the same procedure as described in Example 1 to obtain 1 3.6 g of 1 ,3-bis(3-aminophenoxy)-5-halogenobenzene hydrochloride.

This product was neutralized and then analyzed with a high-performance liquid chromatography to reveal that the product comprised 1,3-bis(3-aminophenoxy)-5-chlorobenzene and 1,3bis(3-aminophenoxy)-5-bromobenzene in a ratio of 93 to 7.

Claims (8)

1. 1,3-Bis(3-aminophenoxy)-5-bromobenzene.

2. 1,3-Bis(3-aminophenoxy)-5-chlorobenzene.

3. A process for preparing a compound as claimed in claim 1 or claim 2, which comprises reacting a 1 ,3,5-trihalobenzene (in which each halogen atom is Br or Cl) with 3-aminophenol, in the presence of a dehydrohalogenating agent.

4. A process according to claim 3, wherein the dehydrogenating agent is a hydroxide, carbonate, bicarbonate or alkoxide of an alkali metal.

5. A process according to claim 3 or claim 4, which is conducted at from 1 20 to 240 C.

6. A process according to any of claims 3 to 5, which is conducted in an aprotic polar solvent.

7. A process according to claim 6, wherein the solvent is selected from N-methylformamide, N,N-dimethylformaide, N, N-dimethylacetamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, N-methylpyrrolidone, 1, 3-dimethyl-2-imidazolidonone and hexamethylphosphoric triamide.

8. A process for preparing a compound as claimed in claim 1 or claim 2, substantially as described in any of the Examples.