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|
|School Location:||United States -- California|
|Source:||MAI 55/06M(E), Masters Abstracts International|
|Keywords:||Cyclization reactions, Heterocycles, Oximes, Photochemistry, Photosynthesis, Radical ions|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be