Rapid, Efficient, and Green Synthesis of Coumarin Derivatives via Knoevenagel Condensation and Investigating Their Biological Effects

Coumarins as naturally occurring heterocycles are chemically and biologically attractive compounds due to their diverse pharmacological properties. This study aimed to design a green method for the synthesis of coumarin derivatives followed by their biological investigations. To do so, coumarins were synthesized with excellent yields using a one-pot procedure under solvent-free conditions at room temperature with very short reaction times. 1-hexyl-3-methylimidazolium bromide was used as a reaction medium and an alternative for common toxic solvents. The structure of coumarins was confirmed using spectroscopic techniques as well as elemental analysis. The cytotoxicity of coumarins was evaluated against A549 cancerous cells and was found to be non-cytotoxic in nature. Also, their abilities for inhibition of acetylcholinesterase, tyrosinase, and alpha-glucosidase were assessed. The results showed that some derivatives have mild to moderate inhibitory activity (IC50=3.64-5.96 mm) against acetylcholinesterase. The tested coumarins have also moderately inhibited tyrosinase (IC50=3.95-13.96 mm). The results of this study could be useful for the design and development of green and effective methods for the synthesis of new drugs with the core structure of coumarin.