Synthesis of Tricyclic Tetrazoles by Cascade Diazotization/Intramolecular Radical C–H Heteroarylation of Arenes

Abstract

A cascade diazotization/intramolecular radical C–H heteroarylation of 1-benzyloxy-5-aminotetrazoles and 1-phenethyl-5-aminotetrazoles as substrates using sodium nitrite and acetic acid without any heating, catalysis, irradiation, or electrolysis is reported. This one-pot reaction afforded the desired tricyclic tetrazole products in good yields (up to 94%) without isolation of the diazonium salt intermediate under mild reaction conditions.

Alkyl ammonium hydrogen sulfate immobilized on Fe3O4@SiO2 nanoparticles: a highly efficient catalyst for the multi-component preparation of novel tetrazolo[1,5-a]pyrimidine-6-carboxamide derivatives

“…According to literature reports, fused heterocycles bearing a tetrazole core are potent compounds; especially in the field of synthetic drugs, and various methods are developed for the incorporation of tetrazoles into fused heterocycles. Some of such effective synthetic routes include C–H carbonylative annulation of N ,1-diaryl-1 H -tetrazol-5-amines 6 , Ugi 4-component reaction 7 , diazotization of 1-benzyloxy-5-aminotetrazoles and 1-phenethyl-5-aminotetrazoles 8 , three-component reaction of 4-chloro-3-formylcoumarins, sodium azide, alkyl/aryl acetonitriles 9 , [3 + 2]cyclization of azidotrimethylsilane with quinoxalin-2(1 H )-ones 10 , and so-on. Additionally, there is a simple procedure comprised of the multi-component reaction of active methylene compounds such as acetoacetic esters, diverse aldehydes, and 5-amino tetrazole, which is promoted by acid/base catalysts.…”