Three-Component\nSynthesis of 1‑Substituted\n5‑Aminotetrazoles Promoted by Bismuth Nitrate

A nontoxic bismuth-promoted multicomponent synthesis\nof 5-aminotetrazoles\nand bistetrazoles is reported. The reaction of phenyl isothiocyanate,\nNaN<sub>3</sub>, and amine (primary aliphatic, aromatic, and aliphatic\ndiamine) promoted by Bi(NO<sub>3</sub>)<sub>3</sub>·5H<sub>2</sub>O under microwave heating affords good yields, short reaction times,\nsimple workup, and purification without column chromatography. A set\nof diagnostic <sup>1</sup>H NMR signals was identified as a guide\nfor quickly elucidating the exclusive (or main) regioisomer formed,\nwith the stronger electron donor group located at heterocyclic nitrogen\n1. This regioselectivity is strongly dependent on the electronic density\nof the amine. It is opposite to that obtained by several thiourea\ndesulfurization methods promoted by thiophilic metals and metal-free\nprotocols.