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The development of new and convenient methodologies for the efficient synthesis of heteroaromatic ring systems remains an area of high interest. Oxidative cyclizations with radical or radical ion intermediates are potentially useful strategies to achieve these types of cyclizations. Previous studies from our group hypothesized that oxime ether radical ions would be susceptible to intramolecular nucleophilic attack whereas radicals would preferentially react with built-in radical traps. Our research has focused on evaluating different groups (aromatic rings, alkynes, and alkenes) in terms of their nucleophilicity or radical trap ability when built into the oxime derivative at a strategic location. In this thesis we report on an exploratory study dealing with obtaining an understanding for the reactivity of selected heteroatomic ring substrates linked to benzaldehyde oximes and oxime ethers and their potential cyclization patterns in terms of nucleophiles or radical traps. Therefore, we have prepared a series of furanyl, thiophenyl, and pyridinyl-substituted benzaldehyde oximes and oxime ethers and they were subjected to photooxidation processes in controlled conditions monitored by GC/MS and NMR for product formation. The results obtained suggest that under photoinduced electron transfer (PET) conditions oximes yielded the parent aldehyde, but did not undergo cyclization indicating that heteroaromatic rings do not behave as radical traps. Several oxime ethers (especially thiophenyl derivatives) were found to yield what is believed to be a cyclized product via nucleophilic attack by the heteroaromatic ring on the nitrogen of oxime ether.
Advisor: | de Lijser, Peter |
Commitee: | Orchard, Alexandra, Salzameda, Nicholas |
School: | California State University, Fullerton |
Department: | Chemistry |
School Location: | United States -- California |
Source: | MAI 55/06M(E), Masters Abstracts International |
Source Type: | DISSERTATION |
Subjects: | Organic chemistry |
Keywords: | Cyclization reactions, Heterocycles, Oximes, Photochemistry, Photosynthesis, Radical ions |
Publication Number: | 10145422 |
ISBN: | 978-1-369-00949-1 |