Synthesis and in vitro antiprotozoal activities of water-soluble, inexpensive phenothiazinium chlorides

Azure B and a synthetic structural analogue of methylene blue, ethylthioninium chloride, present with antidepressant-like properties

“…While several synthetic routes have been reported for the synthesis of phenothiazinium compounds, many of these yield mixed phenothiazinium products that are notoriously difficult to separate and purify (Lu et al, 2011;Wainwright and Giddens, 2003;Gorman et al, 2006). ETC was successfully synthesised from N,Ndiethyl-p-phenylenediamine according to a patent method (Wischik et al, 2006).…”

3,7‐Bis(N‐methyl‐N‐phenylamino)phenothiazinium Salt: Improved Synthesis and Aggregation Behavior in Solution

“…The easiest strategy to prepare phenothiazinium salts involves the oxidation of phenothiazine by iodine , . However, it is widely known that I 2 may create problems in the nature of the counterion, because the oxidation product of phenothiazine (Scheme , 1 st step) is a salt having a molecular formula [(PTZ) + I – ] 2 · 3I 2 · 2H 2 O, thus it is composed of two phenothiazinium cations, two iodide counterions, three molecules of iodine and two molecules of water.…”

Exploring Flow Procedures for Diazonium Formation

“…The simplest approach we could envisage was to utilize a sulfonic acid functionalized ion exchange matrix to act as an acid source and to ultimately form a corresponding aryl-diazonium sulfate species retained by association to the support [64,65]. Interestingly, we found that a related strategy had already been adopted in batch using a sulfonic acid modified silica [66,67]. In addition we and Filimonov et al had used a polymer bound nitrite source to assist in the formation of various arene-diazoniums [68,69].…”