Intramolecular Homolytic Substitution with Amidyl Radicals: A Free-Radical Synthesis of Ebselen and Related Analogues
作者:Mei C. Fong、Carl H. Schiesser
DOI:10.1021/jo970019t
日期:1997.5.1
H)-ones (1) in yields of 81-91% (R = primary alkyl) and 45% (R = c-Hex). Presumably, these transformations involve formation of amidyl radicals 2 which undergo subsequent intramolecular homolytic substitution at the selenium atom with expulsion of a benzyl radical. PTOC imidate esters derived from 2-(benzylseleno)benzanilide (6, R = Ph) and 2-(benzylseleno)-N-tert-butylbenzamide (6, R = t-Bu) were
辐照衍生自N-丁基-2-(苄基硒代)苯甲酰胺(6,R = Bu),2-(苄基硒代)-N-己基苯甲酰胺(6,R =丁二酮)的吡啶-2-硫代氧羰基(PTOC)亚氨酸酯9的水冷苯溶液6,R = Hex),N-苄基-2-(苄基硒代)苯甲酰胺(6,R = Bn)和2-(苄基硒代)-N-环己基苯甲酰胺(6,R = c-Hex),低250W高压汞灯可提供相应的1,2-苯并亚硒唑-3(2H)-(1),产率为81-91%(R =伯烷基)和45%(R = c-Hex)。据推测,这些转化涉及形成酰胺基2,该酰胺基2随后在硒原子上被分子内均溶取代并驱逐出苄基。不能以这种方式制备衍生自2-(苄基硒基)苯甲酰苯胺(6,R = Ph)和2-(苄基硒基)-N-叔丁基苯甲酰胺(6,R = t-Bu)的PTOC亚氨酸酯。1,通过相应的2,2'-二硒代双(苯甲酰胺)的反应也可以76-85%的收率制备2-Benzisoselenazol-3(2H)-ones(1,R