A decade of synthesis of N-heterocyclic derivatives via magnetically retrievable Fe3O4@SiO2@Cu(II) nanocatalysts: A review (2013-present)

Medicinal chemistry and synthetic organic chemistry rely primarily on C-N bonds for their structures because a variety of biologically active compounds, including natural products and synthetic molecules, contain N-heterocyclic as subunits, and they have been assigned a privileged position in drug development due to their improved solubility and ability to form salts, both of which contribute to oral absorption and bio-availability. In recent years, the copper-catalyzed cross-coupling reactions have progressed rapidly with inexpensive, readily available, insensitive to air, and low-toxicity copper catalysts. The copper-catalyzed coupling strategy has been used to make N-heterocycles, and a wide range of applications have been investigated with excellent functional group tolerance. The current review explores the direct C-N bond formation and cyclization approaches used to fabricate triazole, tetrazole, and various other N-heterocyclic derivatives that are catalyzed by magnetically retrievable copper (II)-impregnated silica-coated iron oxide nanocatalysts.