Method for synthesizing 2-methyl-8-methoxy benzofuran [2, 3-b] pyridine

Abstract

The present invention discloses a method for synthesizing 2-methyl-8-methoxy benzofuran [2, 3-b] pyridine. The method comprises the steps of under alkaline conditions, forming a carbon-oxygen bond through a nucleophilic substitution reaction of 2-chlorine-3-nitro-6-methyl pyridine and guaiacol; under the catalysis of palladium and carbon, carrying out hydrazine hydrate to reduce nitro to generatecorresponding aromatic amine; and carrying out cyclization of the aromatic amine under the action of isoamyl nitrite to synthesize the 2-methyl-8-methoxy benzofuran [2, 3-b] pyridine. As no need to use expensive 2-amino-3-bromine-6-Methylpyridine and 2, 3-dimethoxy phenylboronic acid serving as raw materials, the method has an obvious cost advantage; and meanwhile, the nucleophilic substitution reaction and a diazotization reaction which are simple to operate are adopted in the first two steps of the method, therefore a Suzuki coupling reaction with higher operation requirements and needing corresponding noble metal palladium as a catalyst can be replaced. The method has the advantages of high reaction yield, low production cost, simple post-treatment process and high product purity, and is suitable for process scale up.

Description

technical field [0001] The invention belongs to the technical field of synthesis of organic electroluminescence material intermediates, and in particular relates to a synthesis method of 2-methyl-8-methoxybenzofuro[2,3-b]pyridine. Background technique [0002] In recent years, organic optoelectronic materials have become more and more popular. First, the raw material cost of organic optoelectronic materials is lower than that of inorganic materials, which has a significant cost advantage; second, the inherent properties of organic materials, such as flexibility, make it possible Applied to the preparation of flexible materials. Organic photoelectric materials include organic light-emitting diodes, organic phototransistors, organic photovoltaic cells, and organic photodetectors. Among them, organic light-emitting diodes (referred to as OLEDs) exhibit significantly better characteristics than traditional light-emitting materials. OLEDs use organic thin films on devices In the...

AI Technical Summary

Problems solved by technology

The starting material 2-amino-3-bromo-6-picoline of this method is very expensive, and 2,3-dimethoxyphenylboronic acid also needs to be prepared by o-dimethoxybenzene, and the raw material cost of the route is too high

In addition, the suzuki coupling reaction in the first step requires the use of tetrakistriphenylphosphine palladium with a molar ratio of 3%, and tetrakistriphenylphosphine palladium has high activity and is easy to oxidize and deteriorate, which requires the consumption of a large amount of precious metal catalysts

The coupling reaction has high requirements for operation, requires inert gas protection, and produces a large amount of waste water containing organic solvents and salts, which increases the cost of hazardous waste treatment

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