New facile tandem route to oxo- and thioxo[1,2,4]triazolo[1,5-a]pyridinium salts
(Chemical Equation Presented) 2-Arylsulfanyl- and benzylsulfanylpyridinium N-arylimides (2), easily available from tetrazolo[1,5-b]-pyridinium salts (1), participate in 1,3-dipolar cycloaddition with aryl isothiocyanates and aryl isocyanates to result in