Synthesis of benzofuran derivatives and their biological evaluation

In the last years we largely investigated a method for oxy-functionalize the aromatic ring of natural occurring compounds, in order to enhance their biological activities (1). The method involves a methanolysis of an aromatic bromide; the bromination of activated aromatic rings can be performed by a number of methods (2), but the most efficient and clean was that in which the electrophilic species is generated in situ by the oxidation of NaBr with oxone (3). This bromination/methanolysis sequence was recently used also in the development of a synthetic strategy for the preparation of benzofuran and benzopyran derivatives, a group of biological active heterocycles extracted from different plants and used in traditional medicine of some countries. To synthesize 2,3-diidrobenzofuranes and benzofuranes scaffolds for the preparation of more complex molecules, we decided to start from tyrosol, a phenol largely present in olive oil production waste, with no biological importance.