Flavones and Related Compounds: Synthesis and Biological Activity

This review focuses on the synthesis and biological activity of flavones and their related flavonoidic compounds: flavonols and aurones. Among the biological activities of flavones and aurones, the anticancer, antioxidant and antimicrobial properties are highlighted and detailed in this review. The most applied method for the synthesis of flavones and aurones is based on the oxidative cyclisation of o-hydroxychalcones. Depending on the reaction conditions and the structure of the precursor, in some cases several cyclization products result simultaneously: flavones, flavanones, flavonols and aurones. Based on the literature data and the results obtained in our research group, our aim is to highlight the most promising methods for the synthesis of flavones, as well as the synthetic routes for the other structurally related cyclization products, hydroxyflavones and aurones, considering that in practice it is difficult to predict which is the main or exclusive cyclisation product of o-hydroxychalcones under certain reaction conditions.