Preparation method of 2-bromo-1, 3-dimethoxybenzene

Abstract

The invention discloses a preparation method of 2-bromo-1, 3-dimethoxybenzene. The preparation method comprises the following steps: using tetrahydrofuran as a solvent, adding m-dimethoxybenzene, stirring to dissolve, cooling to 5-10 DEG C, slowly dropwise adding n-butyllithium, controlling the internal temperature within 5-10 DEG C, recovering the internal temperature to 20-25 DEG C, and ripeningfor 1-2 hours to obtain an intermediate I; then cooling to-60 DEG C to-70 DEG C by adopting a dry ice-acetone bath, slowly dropwise adding a 1, 2-dibromotetrafluoroethane solution of tetrahydrofuran,recovering the internal temperature to 20-25 DEG C after dropwise adding, and ripening for 2-3 hours; after the reaction is finished, cooling, cooling to 0-5 DEG C by adopting an ice-water bath, dropwise adding 1N diluted hydrochloric acid, and carrying out quenching reaction; then adding ethyl acetate for extraction and liquid separation, sequentially washing the combined organic phase with tapwater and saturated edible salt water and drying with magnesium sulfate and finally performing reaction post-treatment such as vacuum concentration to obtain a yellowish-white acicular crystal crude product; and recrystallizing the crude product with n-hexane to obtain the high-purity 2-bromo-1, 3-dimethoxybenzene, wherein the GC purity can reach 99.9% or above.

Description

technical field [0001] The invention relates to a preparation method for synthesizing high-purity 2-bromo-1,3-dimethoxybenzene, which belongs to the technical field of synthesis of important organic material synthesis intermediates and the development and application of pharmaceutical intermediates. Background technique [0002] 2-Bromo-1,3-dimethoxybenzene is an important fine organic chemical product and pharmaceutical organic synthesis intermediate, which has a wide range of uses, mainly including the synthesis of new organic light-emitting materials, dyes, and New drug synthesis development research. With the continuous development of economy and science and technology, the market demand for 2-bromo-1,3-dimethoxybenzene will increase year by year. Therefore, it is very important to develop a method for synthesizing high-purity 2-bromo-1,3-dimethoxybenzene and realizing industrialization. At present, domestic research reports on the synthesis of 2-bromo-1,3-dimethoxyben...

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Problems solved by technology

At present, domestic research reports on the synthesis of 2-bromo-1,3-dimethoxybenzene, most of which are prepared by reacting m-xylylene dimethyl ether with brominating reagents such as bromine, NBS, hydrobromic acid, etc. However, the reaction selectivity is poor, the side reactions are many, the purification is difficult, and the yield is very low. In addition, the raw material bromination reagent and the waste generated by the reaction have serious pollution to the environment and are not suitable for green industrial production.

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