Synthesis, antimicrobial and cytotoxic evaluation of spirooxindole[pyrano-bis-2H-l-benzopyrans]

Microwave-assisted tandem double condensation between isatins and 4-hydroxycoumarin under zinc triflate catalysis to afford spirooxindoles in excellent yield is reported. The synthesized compounds were screened for their in vitro antibacterial and antifungal activities. The compounds that showed promising antimicrobial activity (3a, 3j and 3m) were studied for their binding affinity towards AmpC-β-lactamase receptor, which revealed that compound 3a is highly stabilized by strong hydrogen bond interactions with in the binding pocket. The synthesized spirooxindoles were also evaluated for their cytotoxic potential against COLO320 adenocarcinoma colorectal cancer cells. Biological assay and in silico studies indicated compound 3n as the most active in terms of low IC₅₀ value (50.7 μM) and least free energy of binding (−8.89 kcal/mol) respectively.