Fe3O4 nanoparticles: A powerful and magnetically recoverable catalyst for the synthesis of novel calix[4]resorcinarenes

A simple synthesis of novel and known calix[4]resorcinarenes derivatives has been achieved by the condensation of resorcinol and different aromatic aldehydes in the presence of catalytic amounts of Fe3O4 nanoparticles under solvent-free conditions. The experimental conditions have been thoroughly optimized and established, allowing significant rate enhancements and good to excellent yields. The reactions can be run safely without using any toxic organic solvents under mild reaction conditions. The Fe3O4 nanoparticles were characterized by powdered X-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR spectroscopy.