Synthesis of Hydroxylated Biphenyl Coumarins as Potential Bioactive Agents

The biphenyl unit is embedded in many structures of bioactive natural products and some of them are present in compounds of high biological relevance like vancomicin and biphenomicins. In our laboratory we have been actively engaged in the synthesis and biological evaluation of hydroxylated natural-like biphenyls. Hydroxylated biphenyls generally manifest higher antioxidant activity and less toxicity than the corresponding monomers.[1a-c]. Recently we have prepared a series of chalcones an aurones based on the biphenylic moiety.[2] Coumarins are naturally occurring compound with a widespread distribution in various plants. Coumarins are biologically active compounds used in various aspects like cosmetic, medicinal and pharmaceutical industries but few examples are reported on dimeric coumarins (e.g. kotanin and desertorin).[3] In the course of our search for novel natural-like hyroxylated bioactive biphenyls, we have synthetized: new biphenylic coumarines by condensation reactions starting from C2 symmetric biphenols. The dimeric coumarins (e.g. 1, and 2a-b) were prepared starting from natural? biphenols. All the dimeric new molecules are currently under evaluation in our laboratories as bioactive compounds. All the synthesis, starting from natural compounds, will be described.