Alkyltelluro Substitution Improves the Radical‐Trapping Capacity of Aromatic Amines. Issue 36 (3rd August 2016)

• Record Type: Journal Article
• Authors: Poon, Jia‐fei; Yan, Jiajie; Singh, Vijay P.; Gates, Paul J.; Engman, Lars
• Is Part Of: Chemistry. Volume 22:Issue 36(2016)
• Page Start: 12891
• Page End: 12903
• Publication Date: 2016-08-03
• Subjects: antioxidants -- amines -- chain-breaking activity -- organotellurium -- regenerable; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201602377
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The synthesis of a variety of aromatic amines carrying an ortho ‐alkyltelluro group is described. The new antioxidants quenched lipidperoxyl radicals much more efficiently than α‐tocopherol and were regenerable by aqueous‐phase N ‐acetylcysteine in a two‐phase peroxidation system. The inhibition time for diaryl amine9 b was four‐fold longer than recorded with α‐tocopherol. Thiol consumption in the aqueous phase was found to correlate inversely to the inhibition time and the availability of thiol is the limiting factor for the duration of antioxidant protection. The proposed mechanism for quenching of peroxyl radicals involves O‐atom transfer from peroxyl to Te followed by H‐atom transfer from amine to alkoxyl radical in a solvent cage. Abstract : Te time : Aromatic amines carrying alkyltelluro groups quench lipidperoxyl radicals more efficiently than α‐tocopherol in chlorobenzene and are regenerable by aqueous‐phase N ‐acetylcysteine. According to the proposed mechanism (see scheme), the compounds are multifunctional in the sense that they, at the same time, are both chain‐breaking and hydroperoxide decomposing.