Synthesis method of medical intermediate 3,5-diiodosalicylic acid

Abstract

The invention discloses a synthesis method of a medical intermediate 3,5-diiodosalicylic acid. The synthesis method comprises the following steps: reacting an ethanol solution serving as a solvent and elementary iodine serving as an iodizating agent with a salicylic acid to synthetize a 3,5-diiodosalicylic acid crude product; purifying and refining by adopting alkalized acid precipitation method; carrying out segmented heat preservation, crystallization, centrifugation and baking to obtain a product 3,5-diiodosalicylic acid. The method has the advantages that the raw materials and auxiliary materials are easily available, reaction process conditions are mild, the operation is safe and simple, stable in product quality, clean and friendly to environment, the problems in the traditional technology that a reddish yellow IC13 impurity is easily generated by adopting IC1 as the iodizating agent and the content of a single iodine compound is high are solved, the purity is over 99.5%, and the conversion rate can be up to 98.5%.

Description

technical field [0001] The invention relates to a synthesis method of a pharmaceutical intermediate, in particular to a synthesis method of a pharmaceutical intermediate 3,5-diiodosalicylic acid. Background technique [0002] As an important industry in the field of fine chemicals, medicine has become the focus of development and competition in the past ten years. With the advancement of science and technology, many medicines have been continuously developed to benefit mankind. The synthesis of these medicines depends on the production of new high-quality pharmaceutical intermediates. At present, my country needs more than 2,000 kinds of raw materials and intermediates for chemical industry every year, and the demand is more than 250 tons. [0003] As the country pays more and more attention to environmental protection issues, the pressure on production enterprises to build environmental protection treatment facilities is increasing. At the same time, coupled with the rapid ...

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Problems solved by technology

[0004] Since the advent of 3,5-diiodosalicylic acid, although people have continuously optimized and improved its synthesis process, the following problems still exist in the existing synthesis process: acetic acid and hydrochloric acid are used as solvents, the amount of acid used is large, and solvent recovery is difficult , high cost, and serious corrosion of production equipment; using ICl as iodide can easily generate red and yellow ICl 3 Problems such as high content of impurities and monoiodine compounds, high energy consumption, low conversion rate, high cost and low purity are not conducive to industrial production