regioselective carbon–sulfur-bond-forming electrophilic aromatic substitution reaction. The reaction occurred under mild conditions, and the products were obtained in good to excellent yields. The method represents an efficient preparation of sulfenyl aza-aromatics, which are useful intermediates for important organic transformations, due to the great importance of functionalized indoles among natural compounds
Easy synthesis of polyphenolic 4-thiaflavans with a ‘double-faced’ antioxidant activity
作者:Giuseppe Capozzi、Cristina Nativi、Paolo Sarri、Pierandrea Lo Nostro、Stefano Menichetti
DOI:10.1039/b100359n
日期:——
Inverse electron demanding DielsâAlder reactions of
o-thioquinones with styrenes, followed by simple manipulations of
the obtained cycloadducts, allowed the synthesis of polyphenolic
4-thiaflavans which showed antioxidant activity miming either flavonoid or
tocopherol behaviour.
A simple synthetic methodology, based on the inverse electron demand hetero DielsâAlder reaction of electron-poor dienic o-thioquinones with electron-rich styrenes used as dienophiles, allowed the preparation of several polyhydroxylated 4-thiaflavans. Such compounds, as a function of the nature and position of the substituents on the aromatic rings, as well as of the oxidation state of the sulfur atom, are able to behave in vitro as efficient antioxidants mimicking the action of catechol containing flavonoids or/and tocopherols. The possibility of joining together the potentialities of two relevant families of natural polyphenolic antioxidants appears particularly appealing since an efficient protection against free radicals and other reactive oxygen species (ROS) depends in vivo upon the synergic action of different antioxidant derivatives.