Assessment of Dihydro[1,3]oxazine‐Fused Isoflavone and 4‐Thionoisoflavone Hybrids as Antibacterials

Abstract A series of isoflavone functionalized 3,4‐dihydro‐1,3‐oxazine hybrids was synthesized in good to excellent yields through a Mannich‐type condensation cyclization reaction 6‐chloro‐7‐hydroxy‐3‐(2‐methoxy‐phenyl)‐chromen‐4‐one or 6‐chloro‐7‐hydroxy‐3‐(2‐methoxy‐phenyl)‐chromene‐4‐thione with formaldehyde and primary amines. After spectroscopic characterization, these newly prepared were evaluated for their antibacterial activities against two each Gram positive ( Staphylococcus aureus Bacillus subtilis ) negative Escherichia coli Pseudomonas aeruginosa bacterial strains. Among the screened compounds, dihydro[1,3]oxazine‐fused 4‐thionoisoflavones( 9 b c exhibited potent inhibitory activity all tested species. Moreover, compound possessed most promising P. B. MIC 16 μg/mL S. E. 32 μg/mL. Further, demonstrated better efficacy (MIC=16 μg/mL) than standard drug ampicillin (MIC=32 it also found be equipotent as . Considering disk diffusion synergistic studies, emerged asmost active showing In addition, no significant hemolysis cytotoxicity observed towards human embryonic kidney (HEK293)cells well Galleria mellonella larvae (in vivo). Hence, has potential further explored alone combination next generation agent.