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Xanthenedione derivatives, new promising antioxidant and acetylcholinesterase i...
Seca, Ana M. L.; Leal, Stephanie B.; Pinto, Diana C. G. A.; Barreto, Maria do Carmo; Silva, Artur M. S.Natural and synthetic xanthone derivatives are well-known for their ability to act as antioxidants and/or enzyme inhibitors. This paper aims to present a successful synthetic methodology towards xanthenedione derivatives and the study of their aromatization to xanthones. Additionally their ability to reduce Fe(III), to scavenge DPPH radicals and to inhibit AChE was evaluated. The results demonstrated that xanth...
New syntheses of potential biologically active xanthones and benzoxanthones
Rocha, Djenisa H. A.; Leal, Stephanie B.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.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 si...
Synthesis of new 1,8-dihydroxy-9h-xanthen-9-ones
Leal, Stephanie B.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.; Cavaleiro, José A. S.XXVth European Colloquium on Heterocyclic Chemistry, Reading, UK, 13 – 17 Agosto de 2012. ; Xanthones have a rather restricted occurrence among higher plants, being found almost exclusively in Guttiferae and Gentianaceae. Xanthones are sometimes found as polyhydroxylated derivatives, exhibiting valuable biological activities [1], but more often bearing a variety of substituents. Xanthones are well known for th...
Synthesis and antioxidant activity of new xanthone-type compounds
Leal, Stephanie B.; Pinto, Diana C. G. A.; Seca, Ana M. L.; Silva, Artur M. S.; Cavaleiro, José A. S.3rd Portuguese Meeting on Medicinal Chemistry and 1st Portuguese-Spanish-Brazilian Meeting on Medicinal Chemistry, Aveiro, 28-30 Novembro 2012. ; Owing to our continuing interest in the synthesis of novel oxygen heterocycles we have recently developed a unique synthetic procedure towards the synthesis of new xanthenodiones (2)[5] and extend the work to their aromatization into xanthones (3). Our aim was also t...
New xanthenodione: synthesis and antioxidant activity evaluation
Leal, Stephanie B.; Pinto, Diana C. G. A.; Seca, Ana M. L.; Silva, Artur M. S.; Cavaleiro, José A. S.6th Spanish-Portuguese-Japanese Organic Chemistry Symposium, Lisboa, de 18 a 20 de Julho de 2012 (Poster Communication). ; Due to the continuing interest of the research group in the synthesis of novel oxygen heterocycles we have recently developed a unique synthetic route towards new xanthenodiones 5 (scheme 1).[6] The application of this methodology in the cyclization of chromone derivatives 4b,c bearing met...
A Novel Short-Step Synthesis of New Xanthenedione Derivatives from the Cyclizat...
Pinto, Diana C. G. A.; Seca, Ana M. L.; Leal, Stephanie B.; Silva, Artur M. S.; Cavaleiro, José A. S.Novel (E)-3-aryl-4-benzylidene-8-hydroxy-3,4-dihydro-1 H-xanthene-1,9(2H)-diones are prepared by the cyclization of (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones efficiently catalyzed with boron tribromide. The (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones are obtained from the Baker–Venkataraman rearrangement of (E,E)-2-acetyl-1,3-phenylene bis(3-phenylacrylate), which is greatly improved under microwave irrad...
A new strategy for the synthesis of 3-cinnamoyl-2-styrylchromones and their tra...
Pinto, Diana C. G. A.; Seca, Ana M. L.; Leal, Stephanie B.; Silva, Artur M. S.; Cavaleiro, José A. S.23rd ISHC Congress will be held in Glasgow, Scotland from July 31 August 4, 2011. ; Chromones are a class of oxygen heterocyclic compounds widely distributed in Nature. 2-Styrylchromones are, however, a small and rare naturally occurring chromones; only three derivatives have been isolated, two from the marine blue green algae Chrysophaeum taylori1 and one from the rhizomes of Imperata cylindrical. Even so, 2...
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