Iron,Cobalt,copper Phthalocyanine-catalyzed Oxidation Of 2-aminobenzyl Alcohols To Synthesize Quinazolines And Quinolines

As an important class of N-heterocycle,quinazolines and quinolines have attracted much attention due to their prevalence in nature products and pharmaceuticals.In recent years,many studies have been reported on the synthesis of these two types of N-heterocyclic compounds,most of which were achieved by adding complex oxidants,in the presence of expensive and toxic catalysts,or harsh experimental conditions.At the same time,metal phthalocyanine(MPc)has attracted our attention because of its advantages such as inexpensiveness,commercial availability,no need for synthesis,and the direct oxidation ability via under oxygen activation.Based on this,this paper studies MPc's-catalyzed the synthesis of quinazolines and quinolines via activation of molecular oxygen.The specific research content is as follows:This methodology utilized 2-aminobenzyl alcohols as the starting material,which reacted with benzonitriles and acetophenones to afford quinazolines and quinolines,respectively.Based on above two model reactions,the reaction conditions were examined independently.With the optimized conditions in hand,the substrate scope of reactants was investigated.It was found that various substrates were well tolerated to afford the corresponding products,which could also applied to aliphatic substrates.After systematic investigation,iron(?)phthalocyanine exhibited the highest catalytic activity for quinazoline synthesis,while copper(?)phthalocyanine displayed the highest catalytic efficiency for quinoline synthesis.Base on previous literatures and control experiments,the existence of the phthalocyanine metal oxyanion intermediate was speculated,which was also detected by mass spectrometry.And the plausible experimental mechanism was proposed.This protocol features operational convenience,commercially available catalyst,environmental benignity,and good functional group compatibility.