general experimental procedure for the synthesis of 1,2-disubstituted benzimidazoles : equimolar amounts of benzylamine 2 ( 1.25 mmol ) and o - amino aniline 3 ( 1.25 mmol ) with reduced organocatalyst 1red ( 0.05 mmol , 4 mol % ) and copper(ii ) bromide ( 0.005 mmol , 0.4 mol % ) were mixed in methanol ( 25 ml ) in an air atmosphere . the reaction mixture was stirred at 45 c for 6 h. then , an additional aliquot of 1red ( 0.025 mmol , 2 mol % ) was introduced into the reaction mixture and the reaction was continued for 18 h. the solvent was then removed by evaporation under reduced pressure and the residue was purified by column chromatography on silica gel ( eluent : dichloromethane / methanol 99:1 v / v ) to afford the desired benzimidazole 4 ( see the supporting information ) . the above procedure is generally representative for all of the products shown in tables 2 and 3 . as a service to our authors and readers , this journal provides supporting information supplied by the authors . such materials are peer reviewed and may be re - organized for online delivery , but are not copy - edited or typeset . technical support issues arising from supporting information ( other than missing files ) should be addressed to the authors
aerobic oxidative c  h functionalization of primary aliphatic amines has been accomplished with a biomimetic cooperative catalytic system to furnish 1,2-disubstituted benzimidazoles that play an important role as drug discovery targets . 
 this one - pot atom - economical multistep process , which proceeds under mild conditions , with ambient air and equimolar amounts of each coupling partner , constitutes a convenient environmentally friendly strategy to functionalize non - activated aliphatic amines that remain challenging substrates for non - enzymatic catalytic aerobic systems .