Method for preparing benzimidazole compound through supported bimetallic catalyst at room temperature

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...

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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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