Reactions of 2,2′-diselenobis(N-alkylbenzamides) with peroxides: A free-radical synthesis of ebselen and related analogues

Article abstract of DOI:10.1016/0040-4039(95)01511-F

N-Alkyl-2-triphenylstannylbenzamides (3, R = Hex, Ph, iso-Pro, tert-Bu), prepared from the corresponding 2-benzylselenobenzamides, react with benzoyl peroxide in benzene, under reflux, to afford the 2,2′-diselenobis(N-alkylbenzamides) (4) in 54-87% yield. Further treatment with benzoyl peroxide or di-tert-butyl peroxide in benzene or chlorobenzene affords the N-alkyl-1,2-benzisoselenazol-3(2H)-ones (2) in 76-85% yield. This transformation presumably involves intermediate amidyl radicals which undergo intramolecular homolytic substitution at selenium to afford the product.