This research set out to continue the exploration and diversification of excited state o-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.
Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.
Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to a new scaffold that contained the biologically relevant beta-lactam fragment.
A summation of engineering work is also included to detail the development and implementation of several new LED irradiators. These irradiators are key to the photochemistry that will be discussed, and their development will serve as a blueprint for future work and improvement.
","abstract_html":"<p>This research set out to continue the exploration and diversification of excited state <em>o</em>-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.</p> <p>Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated <em>o</em>-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.</p> <p>Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to a new scaffold that contained the biologically relevant beta-lactam fragment.</p> <p>A summation of engineering work is also included to detail the development and implementation of several new LED irradiators. These irradiators are key to the photochemistry that will be discussed, and their development will serve as a blueprint for future work and improvement.</p>","abstract_has_math":false,"creators":["Umstead, Weston James"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Andrei Kutateladze, Ph.D.","James Fogelman, Ph.D.","Bryan Cowen","Brian Michel"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-01-01T08:00:00Z","date_published":"2016-01-01T08:00:00Z","updated_at":"2026-07-24T02:02:30Z","subjects":["Beta-lactams","Diversity oriented synthesis","Hydantoins","O-azaxylylenes","Photochemistry","Polyheterocycles","Organic Chemistry"],"languages":["en"],"rights":["Copyright is held by the author. User is responsible for all copyright compliance.
"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.du.edu/etd/1117","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Andrei Kutateladze, Ph.D.","James Fogelman, Ph.D.","Bryan Cowen","Brian Michel"]},{"key":"dc:creator","label":"Author","values":["Umstead, Weston James"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2017-06-30T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Beta-lactams","Diversity oriented synthesis","Hydantoins","O-azaxylylenes","Photochemistry","Polyheterocycles","Organic Chemistry"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright is held by the author. User is responsible for all copyright compliance.
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Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.
Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to a new scaffold that contained the biologically relevant beta-lactam fragment.
A summation of engineering work is also included to detail the development and implementation of several new LED irradiators. These irradiators are key to the photochemistry that will be discussed, and their development will serve as a blueprint for future work and improvement.
"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Photoassisted Generation of Complex N, O, S Polyheterocycles"]}]}],"canonical_facts":{"dc:contributor":["Andrei Kutateladze, Ph.D.","James Fogelman, Ph.D.","Bryan Cowen","Brian Michel"],"dc:creator":["Umstead, Weston James"],"dc:date.available":["2017-06-30T07:00:00Z"],"dc:description.abstract":["This research set out to continue the exploration and diversification of excited state o-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.
Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.
Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to a new scaffold that contained the biologically relevant beta-lactam fragment.
A summation of engineering work is also included to detail the development and implementation of several new LED irradiators. These irradiators are key to the photochemistry that will be discussed, and their development will serve as a blueprint for future work and improvement.
"],"dc:format":["application/pdf"],"dc:identifier":["https://digitalcommons.du.edu/etd/1117"],"dc:language":["en"],"dc:rights":["Copyright is held by the author. User is responsible for all copyright compliance.
"],"dc:subject":["Beta-lactams","Diversity oriented synthesis","Hydantoins","O-azaxylylenes","Photochemistry","Polyheterocycles","Organic Chemistry"],"dc:title":["Photoassisted Generation of Complex N, O, S Polyheterocycles"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-24T02:02:30Z"}