A Straightforward Route to Potent Phenolic Chain-Breaking Antioxidants by Acid-Promoted Transposition of 1,4-Benzo[b]oxathiines to Dihydrobenzo[b]thiophenes

作者：Viglianisi Caterina^*; Amorati Riccardo; Di Pietro Leonardo; Menichetti Stefano

来源：Chemistry - A European Journal, 2015, 21(46): 16639-16645.

DOI：10.1002/chem.201502650

• antioxidants
• electrophilic substitution
• phenols
• S heterocycles
• vitamins

The transformation of simple phenols with limited antioxidant activity into potent chain-breaking antioxidants was achieved by a three-step protocol, consisting of the conversion of phenols into 1,4-benzo[b]oxathiines followed by an unprecedented acid-promoted transposition to o-hydroxydihydrobenzo[b]thiophenes, or dihydrobenzo[de]thiochromenes, starting from phenols or naphthols, respectively. These derivatives, bearing a benzo-fused heterocycle with a sulfide sulfur ortho to the phenolic OH, have a rate constant of reaction with alkylperoxyl radicals (k(inh)) comparable to that of -tocopherol. A solid rationale for the transposition mechanism as well as for the structure-antioxidant activity relationship is presented.

• 出版日期2015-11-9