Method for preparing 2-aminoalkylbenzimidazole derivatives

A technology for aminoalkylbenzimidazole and derivatives, which is applied in the field of preparation of 2-substituted benzimidazole derivatives, and can solve problems such as not obtaining target compounds and having no literature reports

Inactive Publication Date: 2010-03-17
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The synthesis of the compound of 2-aminoalkyl substituted benzimidazole has the report (yield up to 95%) that U.S. Patent (US Patent 3468888,1969) adopts hydrochloric acid to realize as catalyst, but verification experiment proves that under the conditions of report, no The reaction occurr

Method used

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  • Method for preparing 2-aminoalkylbenzimidazole derivatives

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0015] Example 1:

[0016] Add 1.0g glycine, 1.04g o-phenylenediamine, 10ml 85% phosphoric acid, 30ml polyphosphoric acid to a three-necked flask equipped with a thermometer, reflux condenser and stirrer, and heat the reaction in a silicon oil bath to control the reaction temperature at 185°C. The reaction time was 16 hours, and the color of the reaction solution changed from colorless to dark gray and finally to dark blue. After the reaction, the reaction mixture was cooled to room temperature and transferred to a 500 ml beaker. After dilution with 200ml of water, 10% NaOH was slowly added dropwise to neutralize to pH=8, a light gray flocculent precipitate was precipitated, vacuum filtration, the obtained precipitate was washed three times with cold water to obtain a crude product. It was recrystallized with absolute ethanol and decolorized by activated carbon to obtain 1.29 g of light pink powder crystals with a yield of 87.0%. M.P: 228-233℃; IR: 3300cm -1 (N-H), 3055cm -1 (A...

Example Embodiment

[0017] Example 2:

[0018] Add 4.14g L-tyrosine, 2.4g o-phenylenediamine, 20ml 85% phosphoric acid, 50ml polyphosphoric acid into a three-necked flask equipped with thermometer, reflux condenser and stirrer, and heat the reaction in an oil bath to control the reaction temperature At 192°C, the reaction time was 20 hours. After the reaction, the reaction mixture was cooled to room temperature and transferred to a 500 ml beaker. After dilution with 200ml of water, 10% NaOH was slowly added dropwise to neutralize to pH=8, and a dark brown flocculent precipitate was precipitated, which was vacuum filtered, and the obtained precipitate was washed with cold water three times to obtain a crude product. It was recrystallized with absolute ethanol and decolorized by activated carbon to obtain 3.96 g of light brown powdery crystals with a yield of 79.2%. M.P: 233-237°C; IR: 3436cm -1 (N-H), 3100-3650cm -1 (O-H), 1690cm -1 (C=N), 1600-1500cm -1 Four bands (aromatic ring overtone), 1380cm -...

Example Embodiment

[0019] Example 3:

[0020] Add 8.64g of chloroacetic acid and 6.62g of o-phenylenediamine, 20ml of 85% phosphoric acid, 40ml of polyphosphoric acid to a three-necked flask equipped with a thermometer, reflux condenser and stirrer. Heat the reaction in a silicon oil bath to control the reaction temperature of 140- At 145°C, the reaction time was 12 hours, and the color of the reaction solution gradually changed from colorless to light yellow. After the reaction, the reaction mixture was cooled to room temperature and transferred to a 500 ml beaker. After dilution with 200 ml of water, 10% NaOH was slowly added dropwise to neutralize to pH=8, a yellow precipitate was precipitated, which was vacuum filtered, and the obtained precipitate was washed three times with cold water to obtain a crude product. It was recrystallized with absolute ethanol and decolorized by activated carbon to obtain light yellow needle-like crystals with a yield of 82.6%. M.P: 146-150℃; IR: 3458cm -1 (N-H),...

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Abstract

The invention relates to a method for preparing 2-substituted benzimidazole derivatives, in particular to a method for preparing 2-aminoalkylbenzimidazole derivatives. The method is characterized in that substituted o-phenylenediamine and alpha-amino acid are used as main synthesis raw materials, mixed acid of phosphoric acid and polyphosphoric acid is used as a catalyst, a high boiling solvent isused as a reaction solvent, the reaction time is 12 to 20 hours, and the reaction temperature is between 130 and 200 DEG C, wherein the molar ratio of the o-phenylenediamine to the corresponding amino acid is 1:1-3.5, and the molar ratio of the phosphoric acid to the polyphosphoric acid is 1:1-5. Under the catalysis of the mixed acid of the phosphoric acid and the polyphosphoric acid, a carboxylin the amino acid and one amino in the o-phenylenediamine are reacted to generate corresponding amide, the other amino in the o-phenylenediamine and a carbonyl in the amide are reacted to generate animidazole ring, and the reaction process is tracked by using thin-layer chromatography. In order to avoid oxidization of intermediates and other side reactions, the reaction process is protected by using nitrogen.

Description

Technical field: [0001] The invention relates to a preparation method of 2-substituted benzimidazole derivatives, in particular to a preparation method of 2-aminoalkylbenzimidazole. Background technique: [0002] Heterocyclic compounds are mainly five- or six-membered ring systems or fused ring systems containing one or more heteroatoms (O, N or S). These compounds have become research hotspots because of their applications in the fields of bioengineering, food flavor chemistry, organic synthesis and dye chemistry. In recent years, more and more new heterocyclic compounds have been discovered, and new synthetic methods of heterocyclic compounds have also emerged. [0003] There are many kinds of nitrogen-containing heterocyclic compounds, which widely exist in nature and are a hot spot in research and development today. Among them, benzimidazole derivatives are an important class of nitrogen heterocyclic compounds. Due to their good biological activity, pharmacological ac...

Claims

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Application Information

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IPC IPC(8): C07D235/14
Inventor 刘思全王立国王慧
Owner UNIV OF JINAN
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