Method for preparing benzimidazole

A technology of benzimidazole and phenylenediamine, applied in the field of preparation of benzimidazole, can solve problems such as long reaction time, and achieve the effects of rapid synthesis, easy access to equipment, and convenient production scale-up

Inactive Publication Date: 2008-08-06
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, they usually have a long reaction time (at least reflux for 30 minutes, generally 4-6 hours), or require special catalysts (such as metal indium compounds) or special solvents (such as fluorine solvents)

Method used

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  • Method for preparing benzimidazole

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Add 0.810 g (7.5 mmol) of o-phenylenediamine, 0.954 g (9 mmol) of benzaldehyde, 0.162 g of potassium iodide and 0.75 mL of DMF into the Erlenmeyer flask in sequence. Microwave was used to heat indirectly 12 times, each time for 40 seconds. After heating, the Erlenmeyer flask was placed in the air, and the heating was continued after the temperature of the reaction mixture dropped. After the reaction was complete, the resulting mixture was dissolved in ethyl acetate, and then saturated NaHCO 3 solution washing (20mL×2), the organic layer was washed with anhydrous Na 2 SO 4 Dry and concentrate under reduced pressure to obtain crude product. Recrystallization was further purified to obtain 1.320 g of pure benzimidazole compounds with a yield of 91%.

Embodiment 2

[0037] Add 1.080 g (10.0 mmol) of o-phenylenediamine, 1.272 g (12.0 mmol) of benzaldehyde, 0.032 g of potassium iodide and 1.00 mL of ethylene glycol into the conical flask in sequence. Microwave was used to heat indirectly 10 times, each heating was 50 seconds, and after heating, the Erlenmeyer flask was placed in the air, and the heating was continued after the temperature of the reaction mixture dropped. After the reaction was complete, the resulting mixture was dissolved in ethyl acetate, and then saturated NaHCO 3 solution washing (20mL×2), the organic layer was washed with anhydrous Na 2 SO 4 Dry and concentrate under reduced pressure to obtain crude product. Recrystallization was further purified to obtain 1.552 g of pure benzimidazole compounds with a yield of 80%.

Embodiment 3

[0039] Add 0.810 g (6.6 mmol) of 4-methyl-o-phenylenediamine, 0.954 g (9.0 mmol) of benzaldehyde, 0.081 g of potassium iodide and 0.66 mL of DMF into the Erlenmeyer flask in sequence. Microwave was used to heat indirectly 12 times, each time for 40 seconds. After heating, the Erlenmeyer flask was placed in the air, and the heating was continued after the temperature of the reaction mixture dropped. After the reaction was complete, the resulting mixture was dissolved in ethyl acetate, and then saturated NaHCO 3 solution washing (20mL×2), the organic layer was washed with anhydrous Na 2 SO 4 Dry and concentrate under reduced pressure to obtain crude product. Recrystallization was further purified to obtain 1.181 g of pure benzimidazole compounds with a yield of 86%.

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Abstract

The invention relates to a benzimidazole preparation method for drug, catalyst and metal surface treatment agent, which uses o-phenylenediamine and aldehyde as raw materials, uses cheap air as oxidant and uses intermittent microwave heating method to synthesize benzimidazole compound. The invention eliminates the o-phenylenediamine and carboxyl acid (or ester) condensation method of traditional benzimidazole synthesis and eliminates the synthesis method with long reaction time and failure in large scale preparation, to directly synthesis o-phenylenediamine, aldehyde and air in microwave, optimizes reactant proportion, microwave heating time and catalyst or the like, with high-speed reaction, simple operation, low device demand and high yield, which can circulate to continuously synthesize benzimidazole to support the industrial production of benzimidazole compound.

Description

technical field [0001] The invention relates to a preparation method of benzimidazole used for medicine, catalyst, metal surface treatment agent and the like. technical background [0002] Benzimidazoles have a wide range of biological activities, such as anticancer, antifungal, anti-inflammatory, treatment of hypoglycemia and physiological disorders, etc., which are of great significance in medicinal chemistry; and can be used to simulate natural superoxide dismutase (SOD ) active sites to study biological activity, as well as new epoxy resin curing agents, catalysts and surface treatment agents for certain metals, and can also be used as intermediates in organic synthesis reactions. Therefore, the synthetic method of benzimidazole compound has caused people's great interest. [0003] At present, there are many reported methods for synthesizing benzimidazole compounds, mainly through the condensation reaction of o-phenylenediamine and carboxylic acid and their derivatives ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D235/04
Inventor 汪朝阳毛郑州
Owner SOUTH CHINA NORMAL UNIVERSITY
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