Synthesis and Reactivity of Pyronoids in Aqueous Medium

The synthesis and reactivity in aqueous medium of compounds having the 2-and 4-pyrone subunits (pyronoids) are reviewed.The results obtained in aqueous medium are compared with those carried out in organic solvent.Compounds having the 2-pyrone or the 4-pyrone structural subunit (pyronoids) are largely present in nature and have received much attention over the years because of their important pharmacological properties and their role in a number of important biological phenomena.1The basic skeletons of most common pyronoids and some natural pyronoids recently reponed in the literature, are illustrated in Tables 1 and2, respectively.The chemistry of pyronoids has been widely investigated and almost all reactions have been carried out in organic solvent.The aqueous medium has rarely been used, probably because of the low solubility of these compounds in water but recent studies on the use of water as reaction medium have opened new prospects.2Table 1.Basic Skeletons of Pyronoids 2-~yrone 4-~yrone Coumarin Chromone Flavone lsoflavone lsocoumarin Xanthone Benzocoumarin