Synthesis method of 5-bromo-1, 2, 3-trimethoxybenzene

Abstract

The invention provides a synthesis method of 5-bromo-1, 2, 3-trimethoxybenzene, which comprises the steps of S1, by taking o-vanillin as an initial raw material, carrying out hydroxyl para-bromination to obtain 5-bromo-2-hydroxy-3-methoxybenzaldehyde; S2, oxidizing an aldehyde group of the product obtained in the step S1 into a hydroxyl group by using an oxidizing agent to obtain 5-bromo-3-methoxybenzene-1, 2-diphenol; and S3, carrying out methylation on the dihydroxyl of the product obtained in the step S2 to obtain the 2,3,4-trimethoxyphenyl bromide. According to the method, 2-hydroxy-3-methoxybenzaldehyde which is low in price and easy to obtain is used as a starting raw material, NBS or bromine is used as a brominating agent, commercially available sodium percarbonate or calcium percarbonate which is easy to obtain and high in safety is used as an oxidizing agent, and dimethyl carbonate which is low in price and low in toxicity is used as a methylation reagent, so that the use of hydrogen peroxide for easily exploding pipe products, dimethyl sulfate for highly toxic pipe products and the like is avoided, raw materials in the whole process route are low in price and easy to obtain, the operation is easy and convenient, the safety is good, the yield is high, and compared with the prior art, the process technology has the advantages of being novel, economical, safe and efficient.

Description

technical field [0001] The invention relates to the technical field of compound synthesis, in particular to a synthesis method of 5-bromo-1,2,3-trimethoxybenzene. Background technique [0002] Route 1: Conversion from other groups to bromine. Such as: the most commonly used amino group is converted to bromine by diazotization; or triethylgermanium is converted to bromine by N-bromosuccinimide (NBS); [0003] Route 2: The target product is obtained by methylating the phenolic hydroxyl group of the brominated raw material. For example: from 5-bromo-1,2,3-trihydroxybenzene methylated with dimethyl sulfate, or from 4-bromo-2,6-dimethoxyphenol with dimethyl sulfate methylated Derived from; [0004] Route three: 1,2,3-trimethoxybenzene is directly brominated with potassium bromide to obtain the target product, or, 1,2,3-trimethoxybenzene is irradiated with hydrobromic acid in the presence of oxygen and catalyst to bromine Substitute to obtain the target product; [0005] Rout...

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Problems solved by technology

[0007] The raw materials 5-amino-1,2,3-trimethoxybenzene etc. used in literature synthetic route one are all more expensive, so the cost is higher and uneconomical; The raw material 5-bromo-1,2,3-trihydroxybenzene used in route two is also It is more expensive and uses dimethyl sulfate, a highly toxic control product, which is neither economical nor safe; the raw material 1,2,3-trimethoxybenzene used in route three is slightly better but not cheap, and one of them uses potassium bromide Direct bromination with a special catalyst is difficult to achieve due to catalyst problems. Another document uses hydrobromic acid to synthesize the target by light in the presence of oxygen and a special catalyst. Catalyst and equipment problems also limit the practical application of the synthesis. Therefore, this route The economy and practicability are doubtful; the raw material 2,6-dimethoxyphenol used in route four is more expensive, and the highly toxic control product dimethyl sulfate is also used, which is also neither economical nor safe; the raw material 5-bromo- 2-Hydroxy-3-methoxybenzaldehyde is more expensive, and it is neither economical nor safe to use hydrogen peroxide, a highly toxic pipe product, and dimethyl sulfate, a highly toxic pipe product, at the same time.

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