Cyanothioacetamide in heterocyclic chemistry: Synthesis of thiopyran, pyridinethione, thienopyridine, pyridothienotriazine and pyridothienopyrimidinederivatives

Cyanothioacetamide (1) reacted with alpha- and beta -naphthaldehyde Za,b to afford the corresponding 3-naphthyl-2-thiocarboxamidopropenonitriles 3a,b. Compounds 3a,h structures could be elucidated via their reactions with acr ylonitrile, ethyl acrylate ( la,b), N-arylmaleimides 6a-c and ethyl acetoac etate (8). The isolated products could be represented as the thiopyran, thi opyranopyrrolidine and pyridinethione derivatives 5a-d, 7a-f and 9a,b respe ctively. Pyridinethiones 9a,b had been used as the starting materials in th e present study in addition to the next ones to synthesize several new thie nopyridines, pyridothienotriazine and pyridothienopyrimidines 12a-f, 15a,b, 16b, 17-19a,b respectively through their reactions with the corresponding reagents. All structures of the newly synthesized heterocyclic compounds were establi shed on the basis of the data of IR, H-1 NMR and elemental analyses.