Synthesis of 3,4-Dihydroquinoxalin-2-Amine, Diazepine-Tetrazole and Benzodiazepine-2-Carboxamide Derivatives with the Aid of H6P2W18O62/Pyridino-Fe3O4

In the current study, a magnetic inorganic–organic nanohybrid material (HPA/TPI-Fe3O4) was produced and used as an efficient, highly recyclable and eco-friendly catalyst for the one-pot and multicomponent synthesis of 3,4-dihydroquinoxalin-2-amine, diazepine-tetrazole and benzodiazepine-2-carboxamide derivatives with high yields and in a short range of time (20–35 min). The nanohybrid catalyst was prepared by the chemical anchoring of H6P2W18O62 onto the surface of modified Fe3O4 NPs with N-[3-(triethoxysilyl)propyl]isonicotinamide (TPI) linker.The magnetically recoverable catalyst was easily recycled at least ten times without any loss of catalytic activity. The structures of obtained products are certified by 1H and 13C NMR spectra.