Process for preparing 5-methyl pyrazine-2-carboxylic acid

Abstract

The preparation process of 5-methyl pyrazine-2-carboxylic acid with pyruvic aldehyde and o-diaminobenzene as basic material includes the cyclization in the presence of catalyst, oxidation with inorganic oxidant, acidification with sulfuric acid, decarbolxylation, extraction and separation with butanone, crystallization, drying and crushing. The 5-methyl pyrazine-2-carboxylic acid product has smelting point of 164-172 deg.c. The product is used as the intermediate for the medicine for treating diabetes and hyperlipemia.

Description

technical field [0001] The invention relates to a preparation method of 5-methylpyrazine-2-carboxylic acid, which belongs to the preparation of pharmaceutical intermediates. Background technique [0002] With the improvement of people's living standards, the incidence of diabetes and hyperlipidemia is increasing. The demand for drugs to treat such diseases has also increased. 5-Methylpyrazine-2-carboxylic acid is one of the intermediates for the preparation of such drugs. Existing preparation method mainly contains three kinds: one is the synthetic method that uses diaminosuccinonitrile as raw material. Although this method has a simple process route and high conversion rate, the synthesis of diaminobutyronitrile itself requires high temperature, high pressure and highly toxic raw materials. The synthesis route is long and the process conditions are harsh. Therefore, there are no domestic manufacturers to produce it, and the import price is high. Even in foreign countries...

AI Technical Summary

Problems solved by technology

This method is mature, but the synthesis of 2,5-dimethylpyrazine itself is still difficult in the existing domestic conditions, and the import price is high, so it cannot be adopted in consideration of production cost; the third is the fermentation method

Although the process of this method is mature, it is limited by the seasonality of raw materials, and the amount of each fermentation is relatively large, so it is difficult to produce at any time according to market demand. In addition, the product has many impurities (melting point is 160-172°C).

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