Molecular Iodine‐Promoted Transimination for the Synthesis of 6‐Phenylpyrido[2′,1′:2,3]imidazo[4,5<i>‐c</i>]quinoline and 6‐(Pyridin‐2‐yl)pyrido[2′,1′:2,3]imidazo[4,5<i>‐c</i>]quinolines

Abstract

Abstract An unprecedented, efficient I 2 ‐mediated approach for the synthesis of 6‐phenylpyrido[2′,1′:2,3]imidazo[4,5 ‐c ]quinoline heterocyclic skeletons has been achieved from the reaction of benzylamines and 2‐(imidazo[1,2 ‐a ]pyridin‐2‐yl)anilines. This one‐pot protocol proceeds through an oxidation/transimination/cyclization/aromatization reaction sequence under metal‐free conditions to result in the formation of N−C and C−C bonds. A variety of benzylamines, including pyridin‐2‐ylmethanamine, were successfully employed under the optimized conditions as imine precursors in this irreversible transimination reaction with 2‐(imidazo[1,2 ‐a ]pyridin‐2‐yl)anilines to give the corresponding imines. The subsequent cyclization step successfully generated the the corresponding 6‐phenylpyrido[2′,1′:2,3]imidazo[4,5 ‐c ]quinolines.