A Facile Synthesis of New Polyazaheterocycles via One-Pot Three-Components Condensation Reaction and Study of Their Reactions with Nitrilimines

A direct and efficient approach for the synthesis of new series of pyrido[3,4-c][1,5]benzothiazepine, pyrido[4,3-d]triazolo[1',5'-a]pyrimidines, pyrido[4,3-d]tetrazolo [1',5'-a]pyrimidine and pyrido[4,3-4',5']pyrimido[1',2'- a]benzimidazoles has been developed via condensation of o-aminothiophenol and heterocyclic amines each with 1-ethyl- 4-piperidinone and the appropriate aldehyde. The reactions were performed in refluxing acetonitrile in the presence of molecular iodine as a catalyst. Also, the 1,3-dipolar cycloadditions of nitrilimines to the latter products were examined and were found to be site- and regioselective. The structures of the new synthesized compounds were established on the basis of spectral data (Mass, IR, 1H and 13C NMR) and elemental analyses.