Compounding method for 3- ethyoxyl-4-ethoxycarbonyl phenylacetic acid

Abstract

The invention discloses a compounding method for 3- ethyoxyl-4-ethoxycarbonyl phenylacetic acid, comprising the following steps: making 4-methyl salicylate and bromoethane which are used as starting raw materials to carry out double alkylation reaction in N,N-dimethylformamide to prepare 2-ethyoxyl-4-ethyl methylbenzoate; directly dissolving the unpurified 2-ethyoxyl-4-ethyl methylbenzoate into 2-methyl tetrahydrofuran, adding lithium diisopropylamide, and introducing carbon dioxide; acidizing the mixture by sulphuric acid to prepare the 3-ethyoxyl-4-ethoxycarbonyl phenylacetic acid. The product of the invention is white powders with a melting point of 78 to 80 degrees and the content of 99.4%. In the invention, the solvent of N, N-dimethylformamide and 2-methyl tetrahydrofuran can be recycled and repeatedly applied. The invention has the advantages of simple operation, environment friendliness, simple industrial operation, industrial production realization and low cost due to the adoption of the common industrial raw materials.

Description

Technical field: [0001] The invention relates to a method for synthesizing 3-ethoxy-4-ethoxycarbonylphenylacetic acid. Background technique: [0002] Repaglinide is a new drug for regulating blood sugar in the body at the first meal. It belongs to a non-sulfonylurea structure insulin secretion accelerator, which can rapidly promote insulin secretion and reduce glycohemoglobin (HbAlc) and meal blood sugar (PBG) in type II diabetes patients. ), known as "meal blood sugar regulator". The drug was jointly developed by Denmark's Novotel and Germany's Boehringer Ingelham. It was first launched in the United States in April 1998 and in the UK in October of the same year. Listed in China in 2000. The drug is convenient to take orally, has small doses and few side effects, has been marketed in many countries, and can be used as a first-line treatment drug for type II diabetes. 3-Ethoxy-4-ethoxycarbonylphenylacetic acid is a key intermediate in the preparation of repaglinide. 3-Et...

AI Technical Summary

Problems solved by technology

The disadvantage is that tetrahydrofuran and dimethyl sulfoxide cannot be recycled and used mechanically, resulting in an increase in the cost of raw materials

The brominated compound reacts with sodium cyanide in the presence of phase transfer catalyst tetrabutylammonium bromide in dichloromethane and water to obtain ethyl 2-ethoxy-4-cyanobenzoate, which is then hydrolyzed to obtain 2 -Ethoxy-4-carboxymethylbenzoic acid, and then in the presence of potassium carbonate, react with dimethyl sulfate in toluene to obtain a diester, and then perform selective hydrolysis to obtain 3-ethoxy-4-ethoxy Carbonyl phenylacetic acid. The disadvantage is the use of highly toxic dimethyl sulfate, sodium cyanide and carbon tetrachloride, which has been eliminated and banned internationally, and is not suitable for industrial production.

[0012] Document Journal of Medicinal Chemistry, 1998, 41 (26), 5219-5246. through 6 steps reaction (wherein five steps need chromatographic treatment) to get 3-ethoxy group-4-ethoxycarbonyl phenylacetic acid total yield is 50.17% , Product melting point: 70-71 degrees. This route has cumbersome steps, dangerous operation, and high cost, and uses highly toxic cyanide, carbon tetrachloride and hydrogen chloride gas and other reaction reagents. The reaction process requires high-temperature reflux, while hydrolysis It is necessary to control the amount of alkali used, there are many side reactions, and the resulting product is difficult to purify, the quality of the product is poor, and the environmental pollution is relatively large; it is not suitable for industrialized production

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