Copper Pyrrole-imine Incorporated Fe₃O₄-Nanocomposite: A Magnetically Separable and Reusable Catalyst for the Oxidative Amination of Aryl Aldehydes

The present work represents the fabrication of a Fe₃O₄-based nanocomposite Fe₃O₄@CS@PyL-imin@Cu and its application towards oxidative amination of aryl aldehydes to important amides. First, magnetic Fe₃O₄ was coated with chitosan (CS) and then treated with pyrrole-2-carboxaldehyde that produces the desired magnetic nanocatalyst by depositing Cu on its pyrrole-imine functionalized surface. The structure and property of the nanocatalyst are confirmed by all physicochemical technics. The Cu-based magnetic nanocatalyst shows excellent catalytic efficiency toward the oxidative amination of aldehydes with secondary amines to produce corresponding amides (up to 97 % yield) in presence of environmentally benign oxidant H₂O₂. The magnetic nanocatalyst is easily separable with an external magnet and reusable up to the 5^th catalytic cycle without any significant loss of catalytic activity. Overall, a low loading (1.5 mol % of Cu) nanocatalyst has proven to be a practical approach to an alternative to the existing protocol for the preparation of amides.