Coumarins are natural products characterized as 2H-chromen-2-one, according to IUPAC nomenclature, largely distributed in plants, as well as, in species of fungi and bacteria. Nowadays, many synthetic procedures allow the discovery of coumarins with expanded chemical space. The ability to exert non-covalent interactions with many enzymes and receptors in living organisms lead the coumarins to exhibit a wide range of biological activities and applications. Then, this manuscript provides an overview of the use of coumarin compounds in medicinal chemistry in treating many diseases. Important examples of the last years have been selected concerning the activities of coumarins as anticoagulant, anticancer, antioxidant, antiviral, anti-diabetics, anti-inflammatory, antibacterial, antifungal, and anti-neurodegenerative agents. Thus, this work aims at contributing to the development of new rational research projects searching for new treatments and bioactive compounds for many pathologies using coumarin derivatives.

A synthetic procedure for obtaining the fluorescent coumarin umbelliferone (7-hydroxycoumarin) and its spectral parameters were fully developed aiming at an undergraduate organic chemistry laboratory class. Umbelliferone is traditionally prepared via Pechmann condensation using malic acid, resorcinol and sulfuric acid as catalyst. The use of domestic microwave oven and the absence of solvent allow our methodology to be simple, fast and easy applied in obtaining umbelliferone at organic chemistry laboratory being greener than classical techniques of synthesis. In this class the student will learn how to measure the potency of a microwave oven, the applicability of this kind of irradiation in the organic synthesis of fluorescent compounds and how to determine the pKa of an organic compound through an UV/VIS spectrometric analysis. These experiments were designed to be suitable for a second and third year undergraduate curriculum.