The Preparation And Properties Of 1,4-diazaphenoselenazine

Diazaphenothiazines have been used for many years in the control of certain psychopathic conditions such as schizophrenia. Whist doing research at University I wondered about replacing the central sulphur atom with a selenium atom. Selenium, just below sulphur in group 6, has had something of a bad press being considered toxic, and its compounds known to smell much worse than their sulphur analogues! My reasoning was that selenium (despite being lower in the periodic table) was actually much the same size as the sulphur atom. As many molecules display similar pharmacological activity as other of similar shape (due to their ability to fit enzymic active sites) it was reasoned that the ring system containing selenium might have similar - or even enhanced - pharmacological activity over the sulphur analogue. My paper (Tetrahedron Vol 36, pp 2681 to 2683) shows the synthesis and chemistry of this novel ring system.