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Browsing by Author "Patoilo, Diana"

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  • Synthesis of Benzo[a]naphtho[2,3-c]xanthones from 2-styrylchromones
    Publication . Tomé, Sara; Patoilo, Diana; Santos, Clementina M.M.; Silva, Artur
    2-Styrylchromones, a small group of natural occurring chromones vinylogues of flavones (2-phenylchromones) have been ex tensively studied (both by synthesis and transformations)111 due to their known important biological activities. 121 Following our interest in 2-styrylchromones and exploiting its reactivity as synthons in the preparation of other type of compounds, we studied their reactivity as dienophile in the Diels-Alder reaction with ortho-benzoquinodimethanesY1 Another field of interest of our research group is the chemistry of xanthones. 141 This class of oxygen-containing heterocyclic compounds is also associated with a broad spectrum of pharmacological propertiesY1 The interesting biological profile of benzoxanthones 161 is an example that the tricyclic core of xanthones may represent a promising key in medicinal chemistry. In this communication we present a route towards the synthesis of benzo[a]naphtho[2,3-c]xanthones from 2-styrylchromones. Here we discuss the experimental procedures and reaction mechanisms of the Diels-Alder transformation of 2-styrylchromone 1 into the oxidized cycloadduct 3 and its subsequent photoinduced electrocyclization and oxidation that gave access to the desired benzo[a] naphtho[2,3- c]xanthone 4.
    2012Conference object Open access Show more
  • Tetrahydroquinazoline-substituted chromones from Diels–Alder reaction of (E)-2-styrylchromones and pyrimidine ortho-quinodimethane
    Publication . Patoilo, Diana; Silva, Artur; Pinto, Diana; Santos, Clementina M.M.; Tomé, Augusto; Cavaleiro, José
    The Diels-Alder reaction of (E)-2-styrylchromones with a pyrimidine ortho-quinodimethane is reported for the first time. These cycloaddition reactions afford mixtures of two regioisomeric tetrahydroquinazoline-substituted chromones in moderate to excellent global yields. Irrespectively of the substituents on the 2-styrylchromones, the 2-(7-aryl-4-methoxy-2-methyl-5,6,7,8-tetrahydroquinazolin-6-yl)chromone derivatives are always the major isomers.
    2012Journal article Open access Show more