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 (25-35min) 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.