citric acid stabilized on the surface of magnetic nanoparticles as an efficient and recyclable catalyst for transamidation of carboxamides, phthalimide, urea and thiourea with amines under neat conditions

Citric acid-coated magnetic nanoparticles (fe3o4–ca nps) were successfully prepared and characterized. this magnetic nanocatalyst was employed as an efficient, recyclable, and environmentally benign heterogeneous catalyst for the transamidation of carboxamides, phthalimide, urea and thiourea with amines. several derivatives of formylated and transamidated products were synthesized in good to excellent yields in the presence of this catalytic system. and, the catalyst could be easily separated from the reaction mixture using an external magnet and can be reused six times without any significant loss in its catalytic activity.