Oxidation with a "Stopover" - Stable Zwitterions as Intermediates in the Oxidation of α-Tocopherol (Vitamin E) Model Compounds to their Corresponding ortho-Quinone Methides.

ABSTRACT: As a prominent member of the vitamin E group, α-tocopherol is an important lipophilic antioxidant. It has a special oxidation chemistry that involves phenoxyl radicals, quinones and quinone methides. During the oxidation to the ortho-quinone methide, an intermediary zwitterion is formed. This aromatic intermediate turns into the quinone methide by simply rotating the initially oxidized, exocyclic methyl group into the molecule's plane. This initial zwitterionic intermediate and the quinone methide are not resonance structures but individual species, whose distinct electronic structures are separated by a mere 90° bond rotation. In this work, we hindered this crucial rotation, by substituting the affected methyl group with alkyl or phenyl groups. The alkyl groups slowed down the conversion

SUBMITTER: Bohmdorfer S 

PROVIDER: S-EPMC8015729 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature