Tetrahydronaphthalene as a precursor of new series of chalcones, flavanones, and flavones

Authors: AHMED MEDDEB, GHALIA BOUHALLEB, JULIEN LEGROS, FARHAT REZGUI

Abstract: An efficient synthetic route for a novel series of chalcones 2a-2d as well as for the corresponding flavanones 3a-3d and flavones 4a-4d, using functionalized tetrahydronaphthalene (THN), is described herein. The Claisen-Schmidt condensation of such THN and aromatic aldehydes, in the presence of an aqueous solution of KOH (40%), selectively gives the expected chalcones 2a-2d, which may further undergo an intramolecular oxa-Michael addition using piperidine, affording the corresponding flavanones 3a-3d in high yields. Alternatively, treatment of such chalcones 2a-2d with I$_{2}$/DMSO provides rapidly, in a one-pot oxidative cyclization, a series of flavones 4a-4d in excellent yields ranging from 85% to 90%.

Keywords: Morita-Baylis-Hillman, tetrahydronaphthalene, chalcone, flavanone, flavone

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