Preparation method of 5-bromobenzofuran

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of 5-bromobenzofuran. The preparation method of 5-bromobenzofuran comprises the following steps: p-bromophenol and 2-bromoacetaldehyde dimethyl acetal or 2-chloroacetaldehyde dimethyl acetal react for several hours at a proper temperature in the presence of proper solvent and alkali to generate 1-bromo-4'-(2,2-dimethoxyethyl) benzene; the 1-bromo-4'-(2,2-dimethoxyethyl) benzene is heated in the corresponding solvent in the presence of acid, and experiences a cyclization reaction; the product is purified to obtain 5-bromobenzofuran. The method provided by the invention has the beneficial effects that 5-bromobenzofuran is prepared by a two-step process in the reaction, the operation is simple and convenient, the production cost is reduced, and industrial large-scale production is easy to realize; meanwhile, environmental pollution caused by a heavy metal catalyst is avoided.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a preparation method of 5-bromobenzofuran. Background technique [0002] Benzofuran and its derivatives are very important organic compounds, which have high biological activity and widely exist in the framework of many natural products. Therefore, the synthesis of benzofuran and its derivatives has received extensive attention. There are many literatures reporting the synthesis of benzofuran ring. The classic synthesis of benzofuran is obtained by O-alkylation of salicylaldehyde with chloroacetic acid followed by dehydration. In recent years, it is also obtained by O-alkylation of phenol and its derivatives with chloroacetaldehyde or bromoacetaldehyde, and then dehydration under the action of acid. [0003] Benzofuran compounds have various biological activities such as antihistamine, antitumor and antiarrhythmia, and many of these active compounds are expected to become drugs ...

AI Technical Summary

Problems solved by technology

Traditional methods have played an important role in the synthesis of biologically active benzofurans, but there are generally problems such as long routes, harsh substrate and reaction conditions, and limited expansion of substituted functional groups.

Using palladium and other precious metals as catalysts to synthesize benzofuran can overcome the shortcomings of traditional synthesis methods, and the yield has been further improved, but the cost is higher

In recent years, the cheap transition metal copper has gradually become a new hotspot of people's research. The research on using copper as a catalyst to synthesize benzofuran has achieved relatively gratifying results, but there are still limitations in substrates and expensive reagents, etc. shortcoming

Although these achievements are very successful, their industrial production has encountered great challenges, and the heavy metal catalysts used will cause pollution to the environment

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