One-pot catalytic synthesis method of 5-aminosalicylic acid

Abstract

According to the invention, an aniline synthesis method of 5-aminosalicylic acid is improved, and a one-pot catalytic synthesis method of 5-aminosalicylic acid is provided. The method comprises the following steps: reacting aniline with sodium nitrite to generate aniline diazonium liquid; coupling the aniline diazonium solution with salicylic acid under an alkaline condition to generate a 5-(phenylazo)salicylic acid sodium salt solution; directly adding a recyclable catalyst palladium on carbon or raney nickel without separating the 5-(phenylazo) salicylic acid sodium salt, feeding hydrogen for reduction, filtering out the catalyst after the reduction reaction is finished, distilling aniline, adjusting the pH value with hydrochloric acid, and crystallizing the reaction product to obtain the 5-aminosalicylic acid. According to the method, the operation steps are reduced, the yield is increased, the wastewater discharge is reduced, and the industrial production process of the 5-aminosalicylic acid is optimized.

Description

technical field [0001] The invention belongs to the field of medicine and relates to a one-pot catalytic synthesis method of 5-aminosalicylic acid. Background technique [0002] 5-Aminosalicylic acid is an important medicine and dye intermediate. As a medicine, 5-aminosalicylic acid is used as an anti-ulcer drug. By acting on the intestinal inflammatory mucosa, it inhibits the synthesis of prostaglandins that cause inflammation and the formation of inflammatory mediator leukotrienes, thereby significantly anti-inflammatory the intestinal wall. It works especially well on the inflamed connective tissue of the intestinal wall. It can be used to treat ulcerative colitis and Crohn's disease (crohn's disease), also known as Crohn's disease. Used as a dye, 5-aminosalicylic acid can undergo various reactions due to the three active reactive groups of amino, hydroxyl and carboxyl on the ring, and it can be used to manufacture a variety of reactive dyes with excellent quality. [...

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Problems solved by technology

[0006] 1) Aniline synthesis method, which uses aniline as a starting material, obtained through diazotization, coupling and reduction, the route is long and the amount of waste water is large;

[0007] 2) Nitrosalicylic acid reduction method, this method is starting raw material with salicylic acid, first obtains 5-nitrosalicylic acid through nitric acid nitration, then under acidic conditions, use iron powder reduction nitro to be amino, after treatment Finally, 5-aminosalicylic acid is separated out under weakly acidic conditions, and the selectivity of the nitration reaction is low, and the total yield is not high;

[0008] 3) Kolbe-Schmitt synthesis method, this method is that p-aminophenol reacts with carbon dioxide under high temperature and pressure to generate 5-aminosalicylic acid, and this process method requires high reaction equipment requirements and high energy consumption under high temperature and high pressure conditions;

[0009] 4) With 2-chloro-5-nitrobenzoic acid as the starting material, add alkali, and a substitution reaction occurs at a certain temperature to generate 2-hydroxyl-5-nitrobenzoic acid; at a certain pressure and temperature, and at a certain temperature Catalyst and alkaline conditions, use Raney nickel to reduce the nitro group to generate 5-aminosalicylic acid. The raw materials for this process are rare and the process is relatively complicated.

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