Friedel–Crafts Chemistry. Part 43. A Convergent Construction of Some New Bridged Aza-Bicyclic Analogues of Azocine, Azonine, and Azecine via Friedel–Crafts Ring Closures

Abstract

Our present study provides an expedient general approach for the synthesis of some novel bridged dibenzo-azocinone, -azoninone, -azecinone, -azocine, -azonine, and -azecine derivatives via Friedel–Crafts intramolecular ring-closure reactions. The methodology is realized by a four-step protocol involving first preparation of 7-methyl-3,3-diphenylindoline through the reduction of 7-methyl-3,3-diphenylindolin-2-one followed by N-alkylations with different haloesters (α-, β- or γ-). The resulting indoline ester derivatives were allowed to react both by addition of Grignard reagents to afford alcohols and by hydrolysis to afford acids. Particular attention has been given to the novel structures especially in regard to the promising pharmaceutical and therapeutic values associated with their skeletons.