Preparation method of 2-arylbenzimidazole

A technology of benzimidazole and aryl group, applied in the field of preparing 2-arylbenzimidazole, can solve the problems of complicated post-processing process, high catalyst cost, long reaction time and the like, and achieves short reaction time, good catalytic effect and low cost low effect

Inactive Publication Date: 2013-05-01
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method successfully synthesized the target product with a high yield, the cost of the catalyst used was high, the

Method used

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  • Preparation method of 2-arylbenzimidazole
  • Preparation method of 2-arylbenzimidazole

Examples

Experimental program
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Example Embodiment

[0021] Example 1:

[0022] 1) Add 0.01mol o-phenylenediamine and 0.01mol benzoic acid to a dry three-necked flask, then add 5mL 1,4-dioxane, and then add 0.001mol of concentrated sulfuric acid with a mass concentration of 98% under stirring. , Keep at 102℃ and reflux for 5h under sufficient stirring to obtain a mixed solution;

[0023] 2) Cool the mixture to room temperature, and then add a 10% NaOH aqueous solution with a mass concentration of 10% to the mixture to make the mixture alkaline and precipitate solids. Then the mixture is filtered under reduced pressure and the solids obtained are naturally air-dried. The 2-phenylbenzimidazole was obtained with a yield of 76%.

[0024] The present invention further provides a comparative example of Example 1, that is, a preparation method for preparing 2-phenylbenzimidazole without adding concentrated sulfuric acid catalyst, and the preparation method is as follows:

[0025] 1) Add 0.01 mol o-phenylenediamine and 0.01 mol benzoic acid to...

Example Embodiment

[0028] Example 2:

[0029] 1) Add 0.01 mol o-phenylenediamine and 0.011 mol benzoic acid to a dry three-necked flask, then add 5 mL of 1,4-dioxane, and then add 0.001 mol of concentrated sulfuric acid with a mass concentration of 98% under stirring. , Keep at 102℃ and reflux for 4.5h under sufficient stirring to obtain a mixed solution;

[0030] 2) Cool the mixture to room temperature, and then add a 10% NaOH aqueous solution with a mass concentration of 10% to the mixture to make the mixture alkaline and precipitate solids. Then the mixture is filtered under reduced pressure and the solids obtained are naturally air-dried. 2-phenylbenzimidazole was obtained with a yield of 85%.

Example Embodiment

[0031] Example 3:

[0032] 1) Add 0.01 mol of o-phenylenediamine and 0.012 mol of benzoic acid to a dry three-necked flask, then add 5 mL of 1,4-dioxane, and then add 0.001 mol of concentrated sulfuric acid with a mass concentration of 98% under stirring. , Keep at 102℃ and reflux for 4h under sufficient stirring to obtain a mixed solution;

[0033] 2) Cool the mixture to room temperature, and then add a 10% NaOH aqueous solution with a mass concentration of 10% to the mixture to make the mixture alkaline and precipitate solids. Then the mixture is filtered under reduced pressure and the solids obtained are naturally air-dried. Obtain 2-phenylbenzimidazole with a yield of 90%, IR (υ max ,KBr, cm -1 ): 1625 (-C=N), 3190 (-NH); 1 HNMR(δppm, CDCl 3 ): 12.96 (s, 1H, -NH), 7.94 (d, 2H, Ar-H), 7.25-7.27 (m, 4H, Ar-H), 7.41-7.44 (m, 1H, Ar-H), 6.90 -6.92 (m, 2H, Ar-H).

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Abstract

The invention provides a preparation method of 2-arylbenzimidazole, which comprises the steps of firstly adding ortho-phenylene diamine and benzoic acid or substituted benzoic acid into a reactor, then adding 1,4-dioxane, dropwise adding concentrated sulfuric acid while stirring, stirring for back flow for 3-5h, obtaining a mixed solution, cooling the mixed solution to the room temperature, adding a NaOH water solution into the mixed solution, allowing a solid to be precipitated in the mixed solution, conducting suction filtrationunder reduced pressure, drying, and obtaining 2-arylbenzimidazole. According to the method, 2-arylbenzimidazole is prepared by taking 1,4-dioxane as a solvent and concentrated sulfuric acid as a catalyst and adopting a one-pot method; concentrated sulfuric acid is cheap, easy to get and good in catalytic effect; therefore, the method is simple in operational process, low in cost, and short in reaction time. In addition, with the adoption of the method, as high yield of 2-arylbenzimidazole can be realized without recrystallization, the post-treatment is simple.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, in particular to a method for preparing 2-arylbenzimidazoles. Background technique [0002] Benzimidazoles are benzoheterocyclic compounds containing two nitrogen atoms. Benzimidazole and its derivatives have good biological activities (such as anticancer, antibacterial, antiparasitic, etc.), and can be used as drug intermediates, and some products have been used in clinical treatment. However, the existing varieties are constantly modified and improved. Research on structures to obtain new varieties with high activity and low toxicity has never been interrupted. In recent years, the synthesis and biological activity of benzimidazoles have increasingly become a hot spot in the research of heterocyclic chemistry. New compounds and new uses have been reported continuously, and related synthesis research has also attracted the attention of researchers. , people are trying to find a more efficient...

Claims

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Application Information

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IPC IPC(8): C07D235/18
Inventor 刘玉婷付青尹大伟蒋闪闪吕博李鑫
Owner SHAANXI UNIV OF SCI & TECH
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