Tungstophosphoric acid embedded magnetic chitosan as a green catalyst for the synthesis of N-cyclohexyl-3-aryl quinoxaline-2-amines

In the present study, a novel catalyst was well designed by incorporating the tungstophosphoric acid into the magnetic chitosan, as highly stable composite, in which the iron oxides were used the strong super-magnetic core. The prepared composite was characterized by several methods, including FTIR, XRD, SEM, TEM and EDS and its catalytic activity was examined in a facile, green and highly efficient one-pot reaction for the synthesis of N-cyclohexyl-3-aryl-quinoxaline-2-amines with o-phenylenediamine, benzaldehyde and cyclohexyl isocyanide in water, under reflux conditions. This heterogeneous catalytic system was separated easily by an external magnet and was reused at least in four runs without pre-activation and appreciable loss in its activity.