A Crossover Mechanistic Investigation of the Wolff vs. photo-Favorskii Rearrangement of Diazo-p-Hydroxyacetophenone: Methoxy Substituent Effects on p-Hydroxyphenacyl Cage; Exploratory Studies of Hydroxyquinoline-Based Phototriggers
Issue Date
2010-01-28Author
Senadheera, Sanjeewa N.
Publisher
University of Kansas
Format
263 pages
Type
Dissertation
Degree Level
Ph.D.
Discipline
Chemistry
Rights
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
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Show full item recordAbstract
A series of substituted p-hydroxyphenacyl (pHP) and 8-hydroxyquinoline photoremovable protecting groups were designed, synthesized and their photochemistry explored. The light-induced release of phosphates, carboxylates, phenyl ethers and molecular nitrogen (N2) was studied. It was found that photorelease of diethyl phosphate from o-methoxy substituted pHP derivatives were 50% more efficient than the m-methoxy derivatives. In addition, convenient, high yield, one-pot syntheses of several p-HP chromophores were made from their corresponding benzoic acids via the α-diazo-p-hydroxyacetophenones. Photochemical and photophysical studies of the diazo pHP derivatives provided insight into the mechanism of N2 release. Time-resolved IR spectroscopic measurements, sensitization and quenching studies and product analyses support a mechanism for nitrogen release that proceeds via a photochemical Wolff rearrangement pathway. A preliminary study on the photochemistry of 1,5-substituted 8-hydroxyquinolines showed a strong dependence on the leaving group and the presence or absence of oxygen for this heterocyclic pHP analog.
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- Chemistry Dissertations and Theses [335]
- Dissertations [4660]
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