Nitro derivatives of phenothiazine

Phenothiazine nitrated to its tetranitro derivative was used by the Germans during World War II as a component of a non-fusible explosive composition known under the name of Pressling . Monard, Ficheroulle and Fournier [45] found the compound to be phenothiazine tetranitrosulphoxide (I) (m. p. 368°C)  

The compound may be prepared in 70% yield by the nitration of phenothiazine with a mixture of 98% nitric acid and anhydrous sulphuric acid at 60°C. In addition to nitration, oxidation of the sulphur atom also takes place, resulting in the formation of the sulphoxide. 

Bemthsen [46], Kehrmann and co-workers [47] and Gilman and Shirley [48] also observed similar oxidation of the sulphur atom when nitrating phenothiazine 

Spreng- and Ziindstoffe, Vieweg Sohn, Braunschweig, 1921. 

Urbanski, K. Szyc-Lewanska and P. Kalinowski, Bull. Acad. Polon. Sci., ser. chim. 7,147 (1959). 

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