Design and Synthesis of Novel Benzopyran-2-one Derivatives of Expected Antimicrobial Activity through DNA Gyrase-B Inhibition

In an attempt to find a new class of antibacterial agents, we have synthesized thirty new coumarin (2H‐benzopyran‐2‐one) analogues. These derivatives include substituted azetidin‐2‐ones (β‐lactam) 3a–f, pyrrolidin‐2‐ones 4a–f, 2H‐1,3,4‐oxadiazoles 5a–f, and thiazolidin‐4‐ones 6a–f attached to 4‐phenyl‐2H‐benzopyran‐2‐one through an oxyacetamido or an oxymethyl bridge. The target compounds were synthesized starting from 2‐oxo‐4‐phenyl‐2H‐benzo[b]pyran‐7‐yl‐oxyacetic acid hydrazides 2a–f. The new compounds were evaluated as DNA gyrase‐B inhibitors through molecular modeling and docking techniques using the Molsoft ICM 3.4‐8C program. The synthesized compounds were also screened for antibacterial activity against four different species of Gram‐positive and Gram‐negative bacteria; as well as screening against C. albicans for antifungal activity. The molecular modeling data were in accordance with the antimicrobial screening results.