Synthesis of Benzo[a]naphtho[2,3-c]xanthones from 2-styrylchromones
Conference Paper
Overview
Overview
abstract
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.
