Evangelia-Eirini Vlachou
Aristotle University of Thessaloniki, Greece
Title: Synthesis of fused dipyranocoumarins and pyridopyranocoumarins. Biological evalution of the products
Biography
Biography: Evangelia-Eirini Vlachou
Abstract
Dipetalolactone and 4-methyldipetalolactone are prepared in excellent yield by a one-pot tandem propargylation/Claisen rearrangement/cyclization reaction of the corresponding 5,7-dihydroxycoumarins with 3-chloro-3-methylbut-1-yne in the presence of Cs2CO3 under microwave irradiation. The analogous reactions of propargyl chloride with esculetins or 5,7-dihydroxy-coumarins led to dipropargyloxy derivatives. The later by treatment with gold nanoparticles supported on TiO2 or BF3.Et2O in DMF, under microwave irradiation resulted in very good to excellent yield to the corresponding fused dipyranocoumarins. The reactions of esculetins with 3-chloro-3-methylbut-1-yne gave mainly exo-methylene fused dioxino[g]coumarins.
The reactions of 6-amino-7-hydroxycoumarins and 7-amino-6-hydroxycoumarins with propargyl bromide and 3-chloro-3-methylbut-1-yne in the presence of Cs2CO3 under microwave irradiation led to dipropargyl derivatives. The latter by treatment with gold nanoparticles supported on TiO2 or BF3.Et2O in DMF, under microwave irradiation resulted to the corresponding fused pyrido-pyranocoumarins. The new compounds were tested in vitro for their antioxidant and antiinflammatory activities.