Synthesis of tetrazolo[1,5-a]pyridines
The reaction of 2-halopyridines with trimethylsilyl azide in the presence of tetrabutylammonium fluoride hydrate gives tetrazolo[1,5-a]pyridines. 8-bromotetrazolo[1,5-a]pyridine is further transformed into a variety of novel tetrazolo[1,5-a]pyridine derivatives.
J. K. Laha, G. D. Cuny, Synthesis, 2008, 4002-4006.
Treatment of pyridine N-oxides with 4-toluene sulfonyl chloride and sodium azide in toluene at elevated temperature enables an efficient and convenient synthesis of tetrazolopyridines.
S. Liu, D. Lentz, C. C. Tzschucke, J. Org. Chem., 2014, 79, 3249-3254.
Pyridine N-oxides were converted to tetrazolo[1,5-a]pyridines in good yield in the presence of sulfonyl or phosphoryl azides and pyridine by heating in the absence of solvent. Diphenyl phosphorazidate (DPPA) was the most convenient reagent.
J. M. Keith, J. Org. Chem., 2006, 71, 9540-9543.