Method for catalytically synthesizing 1H-imidazole-4-carboxylic acid through inorganic-salt composite catalyst

Abstract

The invention discloses a method for catalytically synthesizing 1H-imidazole-4-carboxylic acid through an inorganic-salt composite catalyst. Ethyl acetamidoacetate serves as a raw material and is enolized, cyclized, subjected to catalytic oxidation desulfurization and hydrolyzed to prepare the target compound; the method includes the three steps of preparing 2-sulfydryl-4-ethyl imidazolecarboxylate, preparing ethyl imidazole-4-carboxylate and preparing the 1H-imidazole-4-carboxylic acid; the inorganic-salt composite catalyst is prepared in the mode that barium sulfate, ferric nitrate and iron sulfate are compounded. The development method is a synthetic technology which is economical, environmentally friendly and easy to operate; the inorganic-salt composite catalyst is provided and added in an inorganic-salt solid mode, the cost of a raw material of the catalyst is low, a preparing method is environmentally friendly and simple, the selectivity of the catalytic effect of the catalyst is high, the yield is remarkably increased, by products are avoided, the catalyst can be recycled, and the quite high market promotion value is achieved.

Description

Technical field: [0001] The invention discloses a method for synthesizing 1H-imidazole-4-carboxylic acid through composite catalysis of barium sulfate-ferric nitrate-ferric sulfate, which belongs to the technical field of organic synthesis. Background technique: [0002] Imidazole is a component of histidine, skin and even nucleic acid in organisms, and 1H-imidazole-4-carboxylic acid is one of the important ones and has significant biological activity. It can be used as an intermediate to form a series of physiologically active compounds. Some imidazole drugs, such as purines and adenosines, have anti-viral and anti-cancer components; some of these compounds have anti-viral and anti-tumor properties, and some have anti-leukemia effects. At the same time, 1H-imidazole-4-carboxylic acid is also used to synthesize imidazole functionalized poly(propyleneimine) dendritic structure compounds, so it has important chemical application value. [0003] At present, there are not many ...

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Problems solved by technology

[0004] Using Raney nickel to remove mercapto groups, there is a problem that heteroatom sulfur, phosphorus, etc. are toxic to the catalyst Raney nickel, leading to catalyst poisoning, so the amount of catalyst used in actual operation will be much higher than the theoretical value, resulting in an increase in the amount, thereby improving Reduced industrial production costs; at the same time, Raney nickel catalysis requires high pressure, which is inconvenient to operate

The oxidation system mainly includes hydrogen peroxide / acetic acid system, hydrogen peroxide / formic acid system, hydrogen peroxide / heteropolyacid system; however, the main problem of directly using hydrogen peroxide oxidation is that the amount of hydrogen peroxide required is relatively large , it takes 7-8 times the amount to completely oxidize and remove the mercapto group, and an organic acid is needed as the reaction medium. Therefore, it is necessary to quench the excess hydrogen peroxide and neutralize the excess organic acid medium after the reaction

[0013] This method is the closest prior art of the present invention, and this method can have shortened reaction time to a certain extent, has improved yield, but because sodium tungstate good water-soluble property, has influenced its reclaiming in later operation process and Reusability, increased environmental pollution and increased preparation costs

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