Synthesis, Characterization and Structure Activity Relationship Studies of Benzo[b]thiophene Derivatives as Promising Class of Antimicrobial Agents

Here we employed simple chemistry for the synthesis of a new potent series of benzo[b]thiophene containing 2-carbonylchlorides (1), 2-isopropyl carboxamides (2), 2-(piperidin-1-yl)-methanones (3) by nucleophilic chloro cyclocondensation of substituted-cinnamic acids with thionyl chloride to afford benzo[b]thiophene nucleus. The constitution of the products has been delineated by elemental analysis and spectral analyses. The products were assayed for their in vitro antimicrobial assay at different concentrations which were compared with Ampicillin, Chloramphenicol, Ciprofloxacin, Norfloxacin and Griseofulvin as standard drug available. The structure activity relationships of synthesized compounds are also studied. The preliminary in vitro biological screening of the title compounds revealed that compounds 2b, 2c, 2e, 3c and 3h exhibited significant (maximum) antibacterial activities where other compounds showed moderate to low activity.