The formation of relatively stable poor reactive phenoxyl radicals is the mandatory mode of action of all natural and synthetic phenolic antioxidants. Thus, highly unstable and oxidant radical species, like peroxyl and alkoxyl radicals, can be quenched by antioxidant phenols, like alpha-tocopherol or Vitamin E, to give much stable and safer oxygen centered phenoxyl radicals able to decompose, or to regenerate by reduction, without damaging of the surrounding tissue or material. The substitution pattern required to achieved stabilization of the phenoxyl radical has been deeply investigated and the knowledge accumulated has been used for the design of synthetic polyphenolic antioxidants that, in some case, exhibit performances comparable, or even superior, than those of the best natural one.1 In this communication, we report that a sulfur inserted in a benzofused heterocycle can indeed represent an impressive means for the stabilization of phenoxyl radicals.2 Additionally, for certain heteroaromatic derivatives, we demonstrated a considerable and unexpected difference between the sulfur and the oxygen containing systems. Thus, while trying to rationalize this apparent anomaly, we settled out a smart synthetic procedure for the synthesis of phenolic benzo[b]thiophenes, related to alpha-tocopherol or Vitamin E, that showed a remarkable antioxidant activity as it will be discussed in this communication. References 1. Lucarini M.; Pedulli, G. F. Chem. Soc. Rev. 2010, 39, 2106–2119 2. a) Amorati, R.; Cavalli, A.; Fumo M. G:, Masetti, M.; Menichetti, S.; Pagliuca, C.; Pedulli, G. F.; Viglianisi, C. Chem-Eur. J. 2007, 13, 8223-8230; b) Amorati, R.; Catarzi, F.; Menichetti, S.; Pedulli, G. F.; Viglianisi, C. J. Am. Chem. Soc. 2008, 130, 237-244; c) Menichetti, S.; Amorati, R.; Pedulli, G. F.; Bartolozzi, M. G.; Viglianisi, C. Chem-Eur. J., 2011, 17, 12396-12404; d) Viglianisi, C., Di Pietro, L.; Amorati, R.; Menichetti, S. Chem-Eur. J. 2015, 21, 16639-16645.

Stabilization of phenoxyl radicals by adjacent benzofused heterocylcles: Sulfur makes the difference (again) / Meoni, Valentina; Viglianisi, Caterina; Tofani, Lorenzo; Amorati, Riccardo; Menichetti, Stefano. - STAMPA. - (2016), pp. 101-102. (Intervento presentato al convegno 27th International Symposium on Organic Chemistry of Sulfur, Jena, Germany, 24-29 July 2016 tenutosi a Jena, Germany nel 24-29 July 2016).

Stabilization of phenoxyl radicals by adjacent benzofused heterocylcles: Sulfur makes the difference (again)

VIGLIANISI, CATERINA;TOFANI, LORENZO;MENICHETTI, STEFANO
2016

Abstract

The formation of relatively stable poor reactive phenoxyl radicals is the mandatory mode of action of all natural and synthetic phenolic antioxidants. Thus, highly unstable and oxidant radical species, like peroxyl and alkoxyl radicals, can be quenched by antioxidant phenols, like alpha-tocopherol or Vitamin E, to give much stable and safer oxygen centered phenoxyl radicals able to decompose, or to regenerate by reduction, without damaging of the surrounding tissue or material. The substitution pattern required to achieved stabilization of the phenoxyl radical has been deeply investigated and the knowledge accumulated has been used for the design of synthetic polyphenolic antioxidants that, in some case, exhibit performances comparable, or even superior, than those of the best natural one.1 In this communication, we report that a sulfur inserted in a benzofused heterocycle can indeed represent an impressive means for the stabilization of phenoxyl radicals.2 Additionally, for certain heteroaromatic derivatives, we demonstrated a considerable and unexpected difference between the sulfur and the oxygen containing systems. Thus, while trying to rationalize this apparent anomaly, we settled out a smart synthetic procedure for the synthesis of phenolic benzo[b]thiophenes, related to alpha-tocopherol or Vitamin E, that showed a remarkable antioxidant activity as it will be discussed in this communication. References 1. Lucarini M.; Pedulli, G. F. Chem. Soc. Rev. 2010, 39, 2106–2119 2. a) Amorati, R.; Cavalli, A.; Fumo M. G:, Masetti, M.; Menichetti, S.; Pagliuca, C.; Pedulli, G. F.; Viglianisi, C. Chem-Eur. J. 2007, 13, 8223-8230; b) Amorati, R.; Catarzi, F.; Menichetti, S.; Pedulli, G. F.; Viglianisi, C. J. Am. Chem. Soc. 2008, 130, 237-244; c) Menichetti, S.; Amorati, R.; Pedulli, G. F.; Bartolozzi, M. G.; Viglianisi, C. Chem-Eur. J., 2011, 17, 12396-12404; d) Viglianisi, C., Di Pietro, L.; Amorati, R.; Menichetti, S. Chem-Eur. J. 2015, 21, 16639-16645.
2016
27th International Symposium on Organic Chemistry of Sulfur, Jena, Germany, 24-29 July 2016
27th International Symposium on Organic Chemistry of Sulfur, Jena, Germany, 24-29 July 2016
Jena, Germany
Meoni, Valentina; Viglianisi, Caterina; Tofani, Lorenzo; Amorati, Riccardo; Menichetti, Stefano
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1055264
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