Synthetic Methods Applied in the Preparation of Coumarin-based Compounds

Coumarins (2H-chromen-2-ones) are heterocyclic compounds of wide scientific interest due to their important biological and pharmaceutical properties such as antitumor, antioxidant, anti-inflammatory and antimicrobial activities as well as enzymatic inhibitors related to neurodegenerative diseases. Due to their structural variability, this compound class has been attracting considerable interest in the natural products and synthetic organic chemistry areas. Coumarins and their derivatives have been prepared by a variety of methods, including Perkin, Wittig and Reformatsky reactions, Pechmann and Knoevenagel condensations, and Claisen rearrangement, among others. In the present review we report the different synthetic methods used in the preparation of coumarin derivatives exploited in the last ten years (from 2008 to 2018), regarding the research demand for new structural scaffolds.