A kind of preparation method of 5-aminosalicylic acid

Abstract

The invention discloses a preparation method of 5-aminosalicylic acid. The method comprises the following steps: 1, preparing 5-nitrosalicylic acid: pre-incubating a salicylic acid solution used as a material 1, a concentrated nitric acid solution used as a material 2 and concentrated sulfuric acid used as a material 3 to a reaction temperature, mixing and reacting the material 1, the material 2 and the material 3, and post-processing the obtained reaction product to obtain purified 5-nitrosalicylic acid; and 2, preparing 5-aminosalicylic acid: dissolving the purified 5-nitrosalicylic acid in a solvent, adding Na2CO3 and a catalyst PdC to obtain a material 4, and carrying out pre-incubation catalytic hydrogenation to reduce the 5-nitrosalicylic acid into 5-aminosalicylic acid. The method has the advantages of simplicity in operation, controllable heat release, short production period, good area selectivity, environmental protection and safety, and realization of high yield and high purity of the finally obtained product.

Description

Technical field [0001] The invention relates to an organic synthesis method, in particular to a preparation method of 5-aminosalicylic acid. Background technique [0002] 5-Aminosalicylic acid (5-ASA, the drug name is mesalazine, also known as masalazine) is the main raw material and active ingredient of sulfasalazine for the treatment of chronic colitis and ulcerative colitis. By inhibiting the synthesis of prostaglandins that cause inflammation and the formation of inflammatory mediator leukotrienes, it significantly inhibits the inflammation of the intestinal mucosa and reduces the release of PGE2 in the human colonic mucosa. [0003] On the other hand, because 5-aminosalicylic acid has three active and reactive groups on the ring: amino, hydroxyl and carboxyl, it can undergo a variety of reactions. Therefore, in the dye industry, it can be used to produce a variety of excellent quality Reactive dyes. [0004] However, the current synthesis method of 5-aminosalicylic acid has th...

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Problems solved by technology

[0004] But there are following defects in the synthetic method of 5-aminosalicylic acid at present: 1, the exothermic heat of nitration reaction is violent, there is certain hidden danger of safe production in industrial large-scale production; 2, can produce a large amount of structural isomers in the reaction process, The ratio of the target product and the structural isomer is close to 1:1, and the chemical properties of the two are very similar so that the purification is difficult, the yield is reduced, and the total yield of the reaction is lower than 30%; 3, 5-aminosalicylic acid in the prior art The synthesis of iron powder will also use concentrated hydrochloric acid, resulting in a large amount of waste acid and iron powder, causing environmental pollution, etc.

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