Long-lasting Antioxidant Protection: A Regenerable BHA-Analogue
2010 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, no 22, 7535-7541 p.Article in journal (Refereed) Published
Introduction of an octyltelluro group ortho to the phenolic moiety in 3-tert-butyl-4-hydroxyanisole (BHA) was found to significantly improve the antioxidant characteristics of the material. In contrast to BHA and the corresponding ortho-substituted octylthio- (9c) and octylseleno (9b) derivatives, the organotellurium 9a was regenerable when assayed for its capacity to inhibit azo-initiated peroxidation of linoleic acid in a chlorobenzene/water two-phase system containing N-acetylcysteine as a stoichiometric reducing agent, and peroxyl radicals were quenched more efficiently than with α-tocopherol. In the homogeneous phase, inhibition of styrene autoxidation occurred with a rate constant kinh as large as 1 × 107 M-1 s-1 but with a low (n = 0.4) stoichiometric factor. Evans-Polanij plots of log (kinh) versus BDE(O-H), which are usually linear for phenols with similar steric crowding reacting by H-atom transfer, revealed that compound 9a was more than 2 orders of magnitude more reactive than expected. Although further mechanistic investigations are needed, it seems that the ortho-arrangement of an alkyltelluro group and hydroxyl should be considered a privileged structure for phenolic antioxidants.
Place, publisher, year, edition, pages
2010. Vol. 75, no 22, 7535-7541 p.
Research subject Chemistry with specialization in Organic Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-133968DOI: 10.1021/jo101239cISI: 000284080300004PubMedID: 20973511OAI: oai:DiVA.org:uu-133968DiVA: diva2:371307