Abstract
The recent interest for new applications of methylene blue as a promising drug for several important ailments prompted us to fill unknown aspects related to this compound. Since there is no mechanism on the Caro synthesis of methylene blue, we provide the electron flow, step by step, from the starting N,N-dimethylphenylenediamine to the dibenzothiazine derivative. It is a free radical generation system due to the oxidizing properties of ferric chloride. We pointed out the alternative reactions that take place with hydrogen sulphide, the reducer from which the thiazine ring is formed.
Highlights
Paul Ehrlich noticed in 1886 that methylene blue turned live neurons blue and had the same effect on plasmodium
The synthesis was not published, but patented a year later to BASF. It consists in the oxidation of p-dimethylaminoaniline and hydrogen sulphide with ferric chloride, [8]
The resulting radical ion is stabilized by deprotonation and radical coupling, b, c
Summary
Paul Ehrlich noticed in 1886 that methylene blue turned live neurons blue and had the same effect on plasmodium. He tested methylene blue as a remedy to treat swamp fever, with success. Methylene blue is used to treat urinary tract infections and as a remedy for cyanide poisoning, and offers many more potential health benefits, [2]. Its reaction mechanism has not been advanced. In this communication we provide the reaction route and the electron flow, step by step. This paper is a follow up of our studies on reaction mechanism, [3,4,5,6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
