Novel one pot synthesis of azolo[1,5-a]pyridines from Viehe's salts

We have developed a practical procedure for the synthesis of polyfunctional azolo[1,5-a]pyridines via the reactive species generated in situ from N-substituted lactams and Viehe's salt. A short reaction sequence, good yields of title compounds (44-69%), as well as their ready isolation, and purification are the distinct advantages of the reported protocol.