Abstract
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, H-1 and C-13 NMR) and elemental analyses.