A nontoxic bismuth-promoted multicomponent synthesis
of 5-aminotetrazoles
and bistetrazoles is reported. The reaction of phenyl isothiocyanate,
NaN3, and amine (primary aliphatic, aromatic, and aliphatic
diamine) promoted by Bi(NO3)3·5H2O under microwave heating affords good yields, short reaction times,
simple workup, and purification without column chromatography. A set
of diagnostic 1H NMR signals was identified as a guide
for quickly elucidating the exclusive (or main) regioisomer formed,
with the stronger electron donor group located at heterocyclic nitrogen
1. This regioselectivity is strongly dependent on the electronic density
of the amine. It is opposite to that obtained by several thiourea
desulfurization methods promoted by thiophilic metals and metal-free
protocols.