Abstract
The versatile enaminonitrile, 2-cyano-3-(dimethylamino)-N-(4-phenylthiazol-2-yl)-acrylamide (2), reacts with some C,O-binucleophiles (acetylacetone and dimedone) in refluxing acetic acid to afford the pyranone 4, the chromene 6 derivatives, and with C,N-binucleophiles (2-(benzothiazol-2-yl)acetonitrile and 2-(1H-benzimidazol-2-yl)acetonitrile) to afford the respective 1H-pyrido[2,1-b]benzothiazole 8 and pyrido[1,2-a]benzimidazole 10 derivatives. Similar treatment of 2 with phenol, resorcinol, -naphthol and -naphthol in boiling acetic acid gave the coumarin derivatives 12, 14, 16, and 18, respectively. The utility of enaminonitrile 2 for the synthesis of 6H-pyrano[3,2-d]isoxazole 20, pyrano[2,3-c]pyrazole 22, and pyrano[2,3-d]pyrimidine 24 derivatives was also explored via its reaction with 3-phenylisoxazol-5(4H)-one, 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, and barbituric acid, respectively. The mechanistic aspects for the formation of the new compounds were also discussed.