Nanomagnetically modified ferric hydrogen sulfate (NiFe2O4@SiO2-FHS): a reusable green catalyst for the synthesis of highly functionalized piperidine derivatives

An efficient and one-pot multi-component procedure for the preparation of functionalized piperidine derivatives from reactions of aromatic aldehydes, substituted anilines and ethyl acetoacetate in the presence of ferric hydrogen sulfate-supported silica-coated magnetic nanoparticles (NiFe2O4@SiO2-FHS) as a magnetically recyclable green catalyst has been developed. The catalysts show environmentally benign character, which can be easily prepared, stored, and recovered several times without obvious significant loss of activity.