Synthesis and antimicrobial testing of some new S-substituted-thiopyridines, thienopyridines, pyridothienopyrimidines and pyridothienotriazines.

The reaction of 5-acetyl-4-aryl-3-cyano-6-methylpyridine-2(1H)-thiones (1a, b) with 4-methylphenacyl bromide, chloro-N-arylacetamides or chloroacetonitrile gave the corresponding S-substituted thiopyridines 2a-c, 4a-f and 6a-c, respectively. The latter compounds underwent intramolecular Thorpe-Ziegler cyclization to give 2-substituted 5-acetyl-3-amino-4-aryl-6-methylthieno[2,3-b]pyridines 3a-c, 5a-f and 7a-c. Compounds 5a-f and 7b, c are key intermediates in the synthesis of the target compounds. Some compounds showed remarkable antimicrobial activity.