Aromatization method of nitrogen-containing heterocyclic compound

A nitrogen heterocyclic compound, aromatization technology, applied in the field of aromatization of nitrogen-containing heterocyclic compounds, can solve the problems of large amount of catalyst, long reaction time, easy over-oxidation, etc., achieve high conversion rate and selectivity, post-treatment The process is simple and the effect of improving biological activity

Pending Publication Date: 2021-12-14
HEBEI VEYONG BIO CHEM
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Problems solved by technology

[0003] In the existing disclosed methods for the aromatization of nitrogen-containing heterocyclic compounds, there are many problems in the reaction process, such as high reaction temperature, long reaction time, complicated operation, low conversion rate and selectivity of raw materials, easy generation of impurities, large amount of catalyst, poor stability and Problems such as low product yield greatly affect the biological activity of nitrogen-containing heterocyclic compounds and their derivatives
For example, in the existing method of aromatizing nitrogen-containing heterocyclic compounds under an oxygen atmosphere using hydrotalcite-like catalysts, the reaction temperature is as high as 80°C, and the reaction process is a heterogeneous system (solid-liquid-gas three-phase), Feedstock conversion and selectivity are low and extremely unstable
There is also a method for preparing triazole compounds through dehydrogenation and oxidation of carbon-nitrogen bonds with sulfur under the action of high-boiling solvent DMF. This process needs to be carried out under DMF reflux conditions, and air is constantly blown in, and the reaction time is longer. The yield is low, and it is easy to produce impurities due to excessive oxidation
It has also been reported that ferric chloride acidified with hydrochloric acid is used as an oxidation reagent for the aromatization of triazole compounds in toluene-ethanol mixed solution or ethanol solution, but the consumption of ferric chloride needs to be far excessive, and a large amount of ferric chloride will be produced during post-treatment. Acidic ferrous chloride aqueous solution, causing environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Synthesis of 3-indoline

[0038] Add 80g of acetonitrile, catalyst (2.13mg, 0.0168mmol ferrous chloride and 6.25mg, 0.0168mmol of EDTA-2Na.2H 2 O), after stirring evenly, add 20g (0.1678mol) 2,3-dihydroindoline, stir, cool down to 10°C, add m-chloroperoxybenzoic acid in 5 batches, the total addition is 34g (0.1510mol, content 85%), after the addition is completed, keep warm at 10°C for 2 hours, and monitor the reaction by liquid chromatography. After the reaction is completed, heat and evaporate to remove the solvent, then add 60g of water, heat to reflux temperature, then cool to -5°C to crystallize, and After incubating at 5°C for 1 h, the crystals were collected by filtration and dried to obtain 19.58 g of the crystallized product 3-indoline, the content of which was detected to be 98.2%, and the yield was 97.8%. Concrete reaction formula is as follows:

[0039]

[0040] Wherein, by liquid phase analysis and detection, calculate the content of 3-hydroindole by e...

Embodiment 2

[0053] Synthesis of 2-methyl-3-indoline

[0054] Add 80g of anhydrous methanol and a catalyst (1.87g, 7.51mmol of copper sulfate pentahydrate and 0.87g, 7.51mmol of 1,2-bis(dimethylamino)ethane) into a 250mL four-neck flask, and stir evenly. Add 20g (0.1501mol) of 2-methylindoline, stir, and add di-tert-butyl peroxide dropwise at 25°C. The amount added is 21.08g. Track and monitor the reaction. After the reaction is completed, add 80g of water, heat to reflux temperature, then cool down to -4°C to crystallize, and keep it at -4°C for 0.5h, collect the crystals by filtration and dry to obtain the crystalline product 2-methyl- 19.60 g of 3-indoline, its content was detected to be 97.8%, and the yield was 97.3% (wherein, the calculation method of yield and content is the same as that of Example 1). Concrete reaction formula is as follows:

[0055]

[0056] Carry out to product 2-methyl-3-indoline 1 HNMR and LC-MS analysis, the characterization data obtained are as follows: ...

Embodiment 3

[0060] Synthesis of 3-Methyl-3,4-Dihydroquinoline

[0061] Add 80g of 2-propanol and 1.02g (5.44mmol) of copper nitrate into a 250mL four-neck flask, stir well, then add 20g (0.1359mol) of 3-methyl-1,2,3,4-tetrahydroquinoline, Stir, heat up to 40°C, add tert-butyl peroxybenzoate dropwise, the amount of addition is 25.86g, after the dropwise addition is completed, keep warm at 40°C for 0.5h, monitor the reaction with liquid chromatography, after the reaction is completed, heat and evaporate to remove the solvent, Then add 100g of water, heat to reflux temperature, then cool down to -6°C to crystallize, and keep it at -6°C for 1h, collect the crystals by filtration and dry to obtain the crystalline product 3-methyl-3,4-dihydroquinoline 19.63 g, the detected content is 97.8%, and the yield is 97.3% (wherein, the calculation method of yield and content is the same as that of Example 1). Concrete reaction formula is as follows:

[0062]

[0063] Carry out to product 3-methyl-3...

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Abstract

The invention relates to the technical field of organic synthesis, and particularly discloses an aromatization method of a nitrogen-containing heterocyclic compound. The aromatization method of the nitrogen-containing heterocyclic compound comprises the following step: by taking the nitrogen-containing heterocyclic compound as a reaction substrate, a transition metal salt or a complex formed by the transition metal salt and an organic compound as a catalyst and peroxide as an oxidant, carrying out reacting in a solvent to obtain a reaction solution containing an aromatization product of the nitrogen-containing heterocyclic compound. The aromatization method of the nitrogen-containing heterocyclic compound provided by the invention has the advantages of mild reaction conditions, small catalyst dosage, simple post-treatment process and high yield and purity of reaction products, is simple to operate, and has extremely high application value.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a method for aromatizing nitrogen-containing heterocyclic compounds. Background technique [0002] Nitrogen-containing heterocyclic compounds and their derivatives (aromatization products) have good biological activity, and are important raw materials for pesticides, medicines, and fine chemicals. For example, indole and its derivatives, quinoline and its derivatives, triazole and its derivatives. [0003] In the existing disclosed methods for the aromatization of nitrogen-containing heterocyclic compounds, there are many problems in the reaction process, such as high reaction temperature, long reaction time, complicated operation, low conversion rate and selectivity of raw materials, easy generation of impurities, large amount of catalyst, poor stability and Problems such as low product yield have greatly affected the biological activity of nitrogen-containing heteroc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/08C07D215/04C07D249/12C07B35/04
CPCC07D209/08C07D215/04C07D249/12C07B35/04
Inventor 赵娜张耀林李志峰赵建芹贾成国
Owner HEBEI VEYONG BIO CHEM
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