Green Chemistry: Synthesis of Multisubstituted 4HChromenes in Water
Chromenes are an significant class of heterocycles that exhibit remarkable effects as pharmaceuticals in various bioactive scaffolds, including anticancer, antifungal, anti-anaphylactin spasmolytic activity. For the synthesis of chromene frameworks, several synthetic protocols have been developed, but most of them suffer from constraints such as harsh reaction conditions, absence of generality, tedious work-up and toxic solvent usage. An expeditious and environmentally safe, general protocol for the synthesis of 2-Amino-3-Cyano-4H-chromenes through the Knoevenagel-Michael-intramolecular cyclization reaction cascade is therefore stated herein. The products were obtained at high (80-95 percent) yields in room temperature water under a catalyst-free reaction. Pure solid products have been obtained by simple techniques of filtration.
Dr. Subrahmanya Ishwar Bhat
Department of Chemistry, NMAM Institute of Technology, Nitte, Karkala 574110, Karnataka, India.
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