A Brief Review on the Synthesis of 4H‐Chromene‐Embedded Heterocycles

Abstract Chromenes are an essential class of oxygen‐containing heterocyclic compounds with intriguing biological activity. It is an important moiety for the discovery of new drug candidates. Chromenes are naturally abundant as alkaloids, tocopherols, flavones, and anthocyanins. The incorporation of 4 H ‐chromene, along with various bioactive heterocycles such as indole, pyrazole, kojic acid, pyran‐2‐one, quinoline, pyridine, pyrimidine, coumarin, sesamol, furan, uracil, benzoimidazole, benzotriazole, thiazole, isoxazole and barbituric acid moieties, into a molecular scaffold has the potential to combine the properties of both components. The synergistic effect of combining different heterocyclic moieties within a 4 H ‐chromene nucleus results in the formation of valuable compounds with significant biological importance. This review summarizes the different synthetic techniques used for preparing 4 H ‐chromene‐embedded heterocycles. The common mechanisms of key reactions and the significance of the method are discussed.