A metal-free C–C/C–O bond formation for the synthesis of 2-amino-5-oxo-4-aryl-4H,5H-pyrano[3,2-c]chromene-3-carboxamide catalyzed by polystyrene-supported p-toluenesulfonic acid (PS-PTSA)

Multicomponent Synthesis Strategies, Catalytic Activities, and Potential Therapeutic Applications of Pyranocoumarins: A Comprehensive Review

Fused coumarins, because of their remarkable biological and therapeutic properties, particularly pyranocoumarins, have caught the interest of synthetic organic chemists, leading to the development of more efficient and environmentally friendly protocols for synthesizing pyranocoumarin derivatives. These compounds are the most promising heterocycles discovered in both natural and synthetic sources, with anti-inflammatory, anti-HIV, antitubercular, antihyperglycemic, and antibacterial properties. This review employed the leading scientific databases Scopus, Web of Science, Google Scholar, and PubMed up to the end of 2022, as well as the combining terms pyranocoumarins, synthesis, isolation, structural elucidation, and biological activity. Among the catalysts employed, acidic magnetic nanocatalysts, transition metal catalysts, and carbon-based catalysts have all demonstrated improved reaction yields and facilitated reactions under milder conditions. Herein, the present review discusses the various multicomponent synthetic strategies for pyranocoumarins catalyzed by transition metal-based catalysts, transition metal-based nanocatalysts, transition metal-free catalysts, carbon-based nanocatalysts, and their potential pharmacological activities.

The molecular diversity scope of 4-hydroxycoumarin in the synthesis of heterocyclic compounds via multicomponent reactions

4-Hydroxycoumarins are some of the most versatile heterocyclic scaffolds and are frequently applied in the synthesis of various organic compounds. 4-Hydroxycoumarin-based compounds are important among heterocyclic structures due to their biological and pharmaceutical activities. In this study, we provide an overview on the recent applications of 4-hydroxycoumarin in multicomponent reactions for the synthesis of various heterocyclic compounds during the time period of 2015-2018.