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Synthesis and Study of a Persistent Selenenic Acid and Preliminary Studies of Thiol Oxidation

Selenenic acids and other organoselenium compounds are important both in
organic and biochemistry. In organic chemistry, syn-elemination of selenoxides is used to
prepare alkenes, giving a selenenic acid by-product. In biochemistry, selenocysteine is
catalytically active in a variety of selenoenzymes, which have antioxidant properties, and
is oxidized to a selenenic acid intermediate. For example, glutathione peroxidase (GPx)
plays a role in fighting oxidative damage by catalyzing the reduction of hydroperoxides.
Previous studies have shown that the lighter chalcogen analogue of selenenic acid,
sulfenic acid, is a powerful antioxidant and that the known antioxidant activity of garlic is
attributable to the 2-propenesulfenic acid derived from the compound allicin. This has
prompted questions concerning the role of selenenic acid in the antioxidant activity of
organoselenium compounds. In order to study the physiochemical properties of selenenic
acids –a functional group about which little is known—and to evaluate their potential as
antioxidants, a persistent selenenic acid is needed. Herein, the model compound,
9-triptyceneselenenic acid, is prepared by a previously reported procedure and a new
pathway is designed, such that its properties and reactivity can be studied.
The oxidation of thiols is important in cell signalling, leading to the disulfide
bonds implicated in post-translational modification, among other biological roles. While
this reaction is presumed to occur through the reaction of thiol with an oxidant that forms
sulfenic acid, and from a subsequent reaction of sulfenic acid with another thiol, sulfenic
acids are so reactive that they are not usually seen as intermediates. Given the stability of
the 9-triptycenesulfenic acid previously synthesized, preliminary kinetic study of the
oxidation of 9-triptycenethiol to its corresponding sulfenic acid is made possible.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OOU.#10393/30718
Date31 March 2014
CreatorsPresseau, Nathalie
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeThèse / Thesis

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