A green, sustainable, and regioselective synthesis of quinolines via C-H activation is reported. CoO@rGO is used as a recyclable catalyst, and PEG-400 acts as the reusable carbon source and reaction medium.

Abstract

A heterogeneous cobalt-catalyzed synthesis of 4-aryl-2-methyl quinolines from cheap and easily available anilines via C-H bond activation/cyclization in the presence of PEG-400 and TfOH is reported here. The cobalt catalyst was easily prepared and characterized, and PEG-400 served as a carbon source in addition to being a solvent. Easy separation and reusability of the catalyst and reaction medium (PEG-400) make the protocol green and sustainable.