A Novel Synthesis of Thienopyridine, Pyrroloquinolinothiophene, Pyrazolopyridin-3-Yl-Phenylthiourea and Thiazolylpyrazolopyridine Derivatives

Dibenzalacetones 1a-c reacted with cyanothioacetamide (2) to give the new styrylpyridinethione derivatives 3a-c which were used as the starting materials for the synthesis of other several heterocyclic compounds. Reactions with chloroacetone (4). N-arylmaleimides 7a,b, and ethyl iodide gave 2-S-acetonyl pyridines 5a-c, pyrrolo[3,4-flquinolines 9a-f, and 2-S-ethylpyridines lla-c, respectively. Several cycloaddition reactions were carried out on 3a-c, 5a-c, and 6a-c with dienophiles 7a,b, to afford the corresponding cycloadducts 9a-f, 10a-f, and 8a-f, respectively. Structures were established based on elemental analyses and spectral data. The antimicrobial activity of the newly synthesized compounds was tested.