Benzoxazole and benzimidazole compounds and preparation method thereof

Abstract

The invention discloses a preparation method of benzoxazole and benzimidazole compounds. A specific structural formula of the benzoxazole and benzimidazole compounds is described in the specification, wherein R1 is aryl, substituted aryl or alkyl; R2 is fluorine, chlorine, methoxyl or methyl; and X is oxygen, nitrogen or nitrogen methyl. The preparation method comprises the following steps: taking amino acid and o-nitrophenol (ortho-nitroaniline) compounds sold on the market as starting materials of reaction, and stirring and heating in a solvent under the catalytic action of an alkaline reagent, so that various substituted benzoxazole and benzimidazole compounds can be obtained with high yield. Reaction conditions are mild, no extra oxidizing agent, reducing agent, ligand or transition metal catalyst needs to be added. The preparation method has the advantages of low cost, simple operation and realization of mass production. Experimental results show that the yield of the obtained benzoxazole and benzimidazole compounds can reach 95%.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a benzoxazole and benzimidazole compound and a preparation method thereof. Background technique [0002] Benzoxazole and benzimidazole compounds are abundant in nature, including biomacromolecules, drug molecules and natural products, and they are a very important class of organic compounds. Benzoxazole and benzimidazole compounds are widely used, and can be used as intermediates of pesticides, spices, and medicines, bioactive molecules such as synthetic proteins, and monomers of functional materials (J.Med.Chem.1995,38,1084; J. Med. Chem. 1991, 42, 4172; J. Med. Chem. 2006, 49, 179.). [0003] Because of the importance of benzoxazole and benzimidazole compounds, they are widely concerned by the chemical, biological and medical circles. However, unfortunately, the traditional preparation method of benzoxazole and benzimidazole compounds is mainly realized by oxidative condensa...

AI Technical Summary

Problems solved by technology

These methods all use some excessive oxidizing agents, such as tert-butyl hydroperoxide, which are prone to explosion and bring some unsafe factors in the actual production process.

At the same time, the biggest problem is that the products prepared by these methods are often limited to 2-aryl quinazolines, and the quinazolines substituted with 2-position fatty acids are not available.

This greatly limits its application prospects

Recently, there are also examples of synthesizing benzoxazole and benzimidazole by hydrogen transfer reaction of o-nitrophenol (o-nitroaniline) and alcohol (benzylamine), but all need to add expensive transition metal nano-catalysts, making the reaction cost Greatly improved, and the preparation process of these transition metal nanocatalysts is relatively complicated, it is difficult to achieve large-scale production (Chem.Commun.2014,50,6145; TetrahedronLett.2015,56,206.)

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