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Method for preparing benzimidazole compounds with supported bimetallic catalyst at room temperature

A bimetallic catalyst and benzimidazole technology, applied in the field of photochemical organic synthesis, can solve the problems of non-recyclable catalyst, difficulty in separation and purification of target compounds, lower reaction temperature, etc., achieve high conversion rate and product selectivity, and wide application range The effect of wide and simple preparation process

Inactive Publication Date: 2018-04-27
HENAN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The traditional method of synthesizing benzimidazole is to use o-phenylenediamine and organic carboxylic acid or derivatives as raw materials through cyclization and dehydration reactions. This method usually requires conditions such as strong acid and high temperature (greater than 200 ° C), and the reaction time is long. And the productive rate is lower; Another kind of method is to adopt o-phenylenediamine and aromatic aldehyde as raw material, prepare benzimidazole derivative through condensation, cyclization and oxidation, though this method can reduce reaction temperature to a certain extent, often needs Add stoichiometric or even higher amounts of oxidizing agents such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), lead tetraacetate, MnO 2 , potassium persulfate, sulfamic acid, ammonium metavanadate, I 2 -H 2 o 2 etc., some of these oxidants are highly toxic in themselves, or produce by-products that pollute the environment, which makes it difficult for the subsequent separation and purification of the target compound
Recently, research results have shown that benzimidazoles can also be synthesized by using trifluoromethanesulfonate as a homogeneous catalyst and oxygen as an oxidant, but these homogeneous catalytic systems often produce seriously polluting by-products, and the catalyst cannot be recycled and reused

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  • Method for preparing benzimidazole compounds with supported bimetallic catalyst at room temperature
  • Method for preparing benzimidazole compounds with supported bimetallic catalyst at room temperature
  • Method for preparing benzimidazole compounds with supported bimetallic catalyst at room temperature

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Embodiment 1

[0034] A method for preparing benzimidazoles with a supported bimetallic catalyst at room temperature, comprising the preparation of the supported bimetallic catalyst and the preparation of the benzimidazoles:

[0035] The preparation method of supported bimetallic catalyst comprises the following steps:

[0036] Step (1) the oxide support TiO of 1.0g 2Disperse to 12.6mL Cu(NO 3 ) 2 With 6.2mL of 0.01M H 2 PtCl 6 In the mixed solution, stir at room temperature for 2 hours to obtain suspension A, then add 7mL of lysine solution with a concentration of 0.1M, continue stirring for 0.5 hours and adjust the pH of the suspension to 8-9 with a NaOH solution with a concentration of 0.3M. Prepare mixed solution B;

[0037] Step (2) Add 2 mL of NaBH with a concentration of 0.35M dropwise to the mixed solution B 4 solution, and then add 3.5mL of HCl solution with a concentration of 0.1M to obtain a mixture C, then leave the resulting mixture C at room temperature for 24 hours, pour...

Embodiment 2-4

[0054] Adopt the method in embodiment 1 to prepare Cu-Pt / TiO 2 Supported bimetallic catalysts.

[0055] Preparation of benzimidazole compounds: add 10mg Cu-Pt / TiO to a 25mL glass reactor 2 Supported bimetallic catalyst and 10mL organic solvent trifluorotoluene (embodiment 2), dichloromethane (embodiment 3) or cyclohexane (embodiment 4), then add 0.3mmol o-phenylenediamine and 0.6mmol ethanol, seal The glass reactor was turned on with a xenon lamp light source, and the reaction was terminated after 5 hours of light. The conversion rate and product structure of o-phenylenediamine were measured by gas chromatography and gas chromatography spectrometer respectively. The reaction results are shown in Table 3.

Embodiment 5

[0063] A method for preparing benzimidazoles with a supported bimetallic catalyst at room temperature, comprising the preparation of the supported bimetallic catalyst and the preparation of the benzimidazoles:

[0064] The preparation method of supported bimetallic catalyst comprises the following steps:

[0065] Step (1) 1.0g oxide support ZrO 2 Disperse to 12.6mL Cu(NO 3 ) 2 With 6.2mL of 0.01M H 2 PtCl 6 In the mixed solution, stir at room temperature for 2.5 hours to obtain suspension A, then add 3 mL of lysine solution with a concentration of 0.3M, continue stirring for 2 hours, and adjust the pH of suspension A to 8-9 with NaOH with a concentration of 0.1M. Prepare mixed solution B;

[0066] Step (2) Add 4.5mL of 0.2M NaBH dropwise to the mixed solution B 4 solution, and then add 1.8mL of HCl solution with a concentration of 0.2M to obtain a mixture C. The resulting mixture C was allowed to stand at room temperature for 36 hours, and the supernatant liquid was pour...

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Abstract

The invention belongs to the technical field of photochemistry organic synthesis, and particularly relates to a method for preparing a benzimidazole compound through a supported bimetallic catalyst at room temperature .The preparation method of the benzimidazole compound comprises the steps that o-phenylenediamine and reactant alcohol are used as initial reactants, a photocatalyst is used as a supported bimetallic nanoparticles, in an organic solvent and under the stirring condition and irradiation of ultraviolet light or visible light or sunlight, the o-phenylenediamine and the reactant alcohol are directly subjected to photocatalysis through light source irradiation to be converted into benzimidazole and a derivative thereof .According to the method, reaction conditions are mild, high-temperature reaction conditions are not needed, the reaction speed at room temperature is high, and the selectivity of the target product benzimidazole is 95% or above .

Description

Technical field: [0001] The invention belongs to the technical field of photochemical organic synthesis, and in particular relates to a method for preparing benzimidazole compounds with a supported bimetallic catalyst at room temperature. Background technique: [0002] Benzimidazoles are heterocyclic compounds containing two nitrogen atoms. They are important intermediates in organic synthesis and have good biological activity. They are widely used in the synthesis of natural products and the pharmaceutical industry. At the same time, it also shows unique performance in high-performance composite materials, electronic chemicals, metal anti-corrosion, photosensitive materials and other fields. The traditional method of synthesizing benzimidazole is to use o-phenylenediamine and organic carboxylic acid or derivatives as raw materials through cyclization and dehydration reactions. This method usually requires conditions such as strong acid and high temperature (greater than 200...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D235/08C07D235/18B01J23/89
CPCB01J23/8926B01J23/898C07D235/08C07D235/18
Inventor 杨娟沈晓晓时建朝张丽娜王潇晗
Owner HENAN POLYTECHNIC UNIV