New syntheses of potential biologically active xanthones and benzoxanthones

10º Encontro Nacional de Química Orgânica e 1º Simpósio Luso-Brasileiro de Química Orgânica, Lisboa, 4-6 Setembro de 2013.

The synthesis of xanthones, adequately functionalized for a specific application, is a challenging task. In this presentation, will be disclosed our recent studies with this unique family of compounds, namely the one-pot photoinduced electrocyclisation of (E)-3-styrylflavones 1 and in situ oxidation of cycloadducts to give 5-phenyl-7H-benzo[c]xanthen-7-one derivatives 2,3a and aromatization studies of (E)-3-aryl-4-benzylidene-8-hydroxy-3,4-dihydro-1H-xanthene-1,9(2H)-diones 33b into 4-benzyl-1,8-dihydroxy-3-phenyl-9H-xanthen-9-one derivatives 4.

We would like to thank Fundação para a Ciência e a Tecnologia (FCT, Portugal), the European Union, QREN, FEDER, COMPETE, for funding the Organic Chemistry Research Unit (QOPNA) (project PEst-C/QUI/UI0062/2011) and the Portuguese National NMR Network (RNRMN).D. H. A. Rocha thanks FCT for her PhD grant (SFRH/BD/68991/2010).