Environmentally friendly and highly efficient synthesis of benzoxazepine and malonamide derivatives using HPA/TPI‐Fe3O4 nanoparticles as recoverable catalyst in aqueous media

A magnetic inorganic–organic nanohybrid material (HPA/TPI-Fe3O4 NPs) was produced as an efficient, highly recyclable and eco-friendly catalyst for the one-pot multi-component synthesis of malonamide and 2,3,4,5-tetrahydrobenzo[b][1,4]oxazepine derivatives with high yields in short reaction times (25–35 min) in aqueous media at room temperature. The nanohybrid catalyst was prepared by the chemical anchoring of H6P2W18O62 onto the surface of modified Fe3O4 nanoparticles (NPs) with N-[3-(triethoxysilyl)propyl]isonicotinamide (TPI) linker. The magnetic recoverable catalyst was easily recycled at least ten times without any loss of catalytic activity.