Chalcones possessing a hydroxyl group in position 2 cyclize to form flavylium salts in acidic media, this reaction being reversible under neutral-basic conditions. On the other hand, chalcones possessing a hydroxyl group in position 2' cyclize to form flavanones in basic media. By synthesizing 2'-hydroxyflavylium tetrafluoroborate, it was possible to obtain trans-2,2'-dihydroxychalcone that in solution can evolve to 2'-hydroxyflavanone or back to 2'-hydroxyflavylium depending on the pH. The several equilibria established in aqueous solution were fully characterized. The importance of including flavanones into the flavylitun network of chemical reactions is briefly exploited. (C) 2007 Elsevier Ltd. All rights reserved.
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Petrov, Vesselin Gomes, Raquel Parola, A. Jorge Jesus, Alexandre Laia, Cesar A. T. Pina, Fernando
Laia, Cesar/C-8651-2011; Pina, Fernando/C-8161-2011; Parola, A. Jorge/F-4048-2010; Caparica, cqfb_staff/H-2611-2013; REQUIMTE, AL/H-9106-2013; Chaves, Pedro/K-1288-2013
Parola, A. Jorge/0000-0002-1333-9076;
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