Synthesis and antimicrobial evaluation of new pyridine, thienopyridine and pyridothienopyrazole derivatives

The reaction of thiocyanoacetamide (1) with alpha,beta-unsaturated ketones 2a,b resulted in the formation of the corresponding newly synthesized 1(H)-pyridinethione derivatives 3a,b. Compounds 3a,b were used as synthons for the preparation of 2-S-alkyl-, 2-S-aryl-, 2-S-acetamidopyridine, thieno[2,3-b]pyridine and pyrazolo[3,4-b]pyridine derivatives via a wide range of reactions with different reagents. The antimicrobial activity of some of the newly synthesized compounds was tested. Compounds 3a, 11a, 15a, and 19a,b were found to be the most active ones.