A method for efficiently preparing 5,6-dihydroxyindole

Abstract

The invention provides a method for preparing a compound that is 5,6-dihydroxyindole, including the following steps: (1) dissolving 3,4-dialkoxy phenethylamine and a catalyst into an organic solvent,performing a reflux reaction under heating and stirring and tracking the reaction process by using thin layer chromatography; (2) after the reaction in step (1) is finished, performing concentration to remove excess acid, adding deionized water, performing extraction with an organic solvent, and then performing purification further to obtain dopamine hydrochloride white solid powder; (3) adding anoxidizing agent into the dopamine hydrochloride, preparing an intermediate compound I through oxidation, and then subjecting the compound I to reduction with a reducing agent to finally obtain 5,6-dihydroxyindole solid powder. The raw materials, the catalyst and the like adopted in the method are cheap and easily available, the reaction yield is high, side reactions are few, the method is suitable for industrial production, and has few operation steps, short reaction flow, and simple post-reaction treatment, and the obtained product has high purity and stability and can be stored for long time.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to an efficient preparation method of compound 5,6-dihydroxyindole. Background technique [0002] 5,6-Dihydroxyindole is an important intermediate of melanogen, which was first found in a plant in nature. Pure 5,6-dihydroxyindole is a colorless needle-like crystal with a melting point of 140°C. It is soluble in hot water but insoluble in petroleum ether; it is very stable in the crystal state, but quickly oxidizes to similar melanin substance. Because it is less irritating to human skin, it is used to replace commonly used aniline compounds (with carcinogenic, teratogenic, and allergic adverse effects) in some cosmetic products as black active ingredients, such as the hair dye of Japan Meiyuan. Use it as one of the main active ingredients. It is also a good antioxidant, and can also be used as an intermediate in the synthesis of some amino acids, alkaloids, and tryptami...

AI Technical Summary

Problems solved by technology

This method has a high yield, which can reach more than 80%, but the experiment takes a long time, and the reaction steps are cumbersome, so it is not suitable for large-scale production.

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