Progress in Multicomponent Reaction Strategies for the Synthesis of 2-Amino-5-Oxo-4-Phenyl-4H,5H-Pyrano[3,2-c][1]benzopyran-3-Carbonitrile Derivatives: A Recent Overview.

This review highlights recent advancements (2021-2025) in the one-pot multicomponent synthesis of 2-amino-5-oxo-4-phenyl-4H,5H-pyrano[3,2-c][1]benzopyran-3-carbonitriles, a class of biologically significant heterocycles with diverse pharmacological properties. The methodologies are categorized based on the type of catalyst used, including deep eutectic solvent-based catalysts, ionic liquid-based catalysts, nanocatalysts, heterogeneous hybrid solid green catalysts, homogeneous base catalysts like piperidine, agro-waste extract, organo-salt catalyst and tertiary base surfactant. These catalytic systems have demonstrated improvements in reaction efficiency, environmental sustainability, and product yields. By organizing these developments, the review provides a valuable resource for guiding future research in green and efficient heterocyclic synthesis.