Copper nanoparticles: A capable and versatile catalyst for the synthesis of diverse 1-phenyl-1H-tetrazoles from amino acids

Abstract Cu nanoparticles were prepared in successive stages: preparation of the Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 MNPs), coating of the Fe 3 O 4 MNPs with tetraethyl orthosilicate (Fe 3 O 4 @SiO 2 ), functionalization of Fe 3 O 4 @SiO 2 with 3-chloropropyltrimethoxysilane (CPTMS) and 4-amino-1,2,4-triazole (AT) ligands (Fe 3 O 4 @SiO 2 @CPTMS@AT), and the complexation of Fe 3 O 4 @SiO 2 @CPTMS@AT with CuCl 2 (Fe 3 O 4 @SiO 2 @CPTMS@AT@Cu). The obtained Cu nano-catalyst was then used for the synthesis of diverse tetrazoles from the reaction of various amino acids with sodium azide and triethyl orthoformate (TEOF) in ethanol at 80 °C.