Abstract: Various selenium-containing compounds are widely used as reagents and intermediates in organic synthesis.¹ In recent years biologically active organoselenium compounds have begun to attract considerable interest due to their unique and diverse potential pharmacological importance such as broad spectrum antitumor and antiviral activities, and some of them are even many times more active than their thio analogues.^2,3 It was found that benzisoselenazolones[e.g.,Ebselen, 2-phenyl-1,2-benzisoselenazol-3(2H)-one], are effective for the treatment of diseases caused by cell damage owing to increased formation of active oxygen metabolites⁴ and these pharmacological effects are mainly attributed to the glutathione peroxidase (GSH-Px) like properties.⁵