Process for production of phenol derivatives substituted with iodine at ortho position

Abstract

To provide a process for producing 2-iodophenol derivatives or 2,6-diiodophenol derivatives by iodinating phenol derivatives at ortho position which can dispense the recovery of iodine and makes it possible to produce the objective iodinated derivatives at low cost, in high yield, and with high quality. High-quality 2-iodophenol derivatives or 2,6-diiodophenol derivatives can be obtained in high yield by reacting a phenol derivative with molecular iodine in the presence of a pyridine and either hydrogen peroxide or iodic acid as oxidizing agent through efficient iodination with a nearly theoretical amount of iodine based on the starting phenol derivative.

Description

technical field The present invention relates to a method for selectively producing 2-iodophenol derivatives or 2,6-diiodophenol derivatives by iodination of phenol derivatives whose one or two substituents at the ortho position are hydrogen. 2-iodophenol derivatives or 2,6-diiodophenol derivatives are compounds useful as raw materials in medicine or agricultural chemistry. For example, examples of 2-iodophenol derivatives include 2-iodo-3-hydroxy-4-methoxybenzonitrile, which is 4-amino-6,7-dimethoxy-2 An important intermediate raw material of -(5-methylsulfonylamino-1,2,3,4-tetrahydroisoquinolin-2-yl)-5-(2-pyridyl)quinazoline. Examples of 2,6-diiodophenol derivatives include 3-(3,5-diiodo-4-hydroxyphenyl)propanoic acid, which is a 3,5- An important intermediate raw material of diiodothyronine. Background technique Generally, (1) a method of reacting an iodine or potassium triiodide aqueous solution with an alkaline aqueous solution is generally known as a method for iodi...

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Problems solved by technology

Therefore, only half the amount of iodine is used for 3-(3,5-diiodo-4-hydroxyphenyl)propionic acid, and a step for collecting and reusing the remaining iodine is required, thus causing these steps to become a complex and costly problem

Also increases the burden of purification due to the production of large amounts of the intermediate by-product 3-(3-iodo-4-hydroxyphenyl)propanoic acid

(4) On the other hand, there have been cases where the iodination of an aromatic compound nucleus using iodine and hydrogen peroxide has been used for the iodination of biphenyl (for example, refer to Patent Document 2), however, it has not been disclosed In the case of phenol derivatives

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