Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for +publisher:"U of Denver" +contributor:("Andrei G. Kutateladze"). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters

1. Valiulin, Roman Askatovich. Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries.

Degree: PhD, Chemistry and Biochemistry, 2010, U of Denver

The main goal of this project was to develop an efficient methodology allowing rapid access to structurally diverse scaffolds decorated with various functional groups. Initially, we discovered and subsequently developed an experimentally straightforward, high-yielding photoinduced conversion of readily accessible diverse starting materials into polycyclic aldehydes and their (hemi)acetals decorated by various pendants. The two step sequence, involving the Diels-Alder addition of heterocyclic chalcones and other benzoyl ethylenes to a variety of dienes, followed by the Paternò-Büchi reaction, was described as an alkene-carbonyl oxametathesis. This methodology offers a rapid increase in molecular complexity and diversity of the target scaffolds. To develop this novel methodology further and explore its generality, we directed our attention to the Diels-Alder adducts based on various chromones. We discovered that the Diels-Alder adducts of chromones are capable of photoinduced alkene-arene [2+2] cycloaddition producing different dienes, which can either dimerize or be introduced into a double-tandem [4π+2π]·[2π+2π]·[4π+2π]·[2π+2π] synthetic sequence, followed by an acid-catalyzed oxametathesis, leading to a rapid expansion of molecular complexity over a few experimentally simple steps. In view of the fact that oxametathesis previously was primarily observed in aromatic oxetanes, we decided to prepare model aliphatic oxetanes with a conformationally unconstrained or "flexible" methyl group based on the Diels-Alder adducts of cyclohexadiene or cyclopentadiene with methyl vinyl ketone. Upon addition of an acid, the expected oxametathesis occurred with results similar to those observed in the aromatic series proving the generality of this approach. Also we synthesized polycyclic oxetanes resulting from the Diels-Alder adducts of cyclic ketones. This not only gave us access to remarkably strained oxetane systems, but also the mechanism for their protolytic ring opening provided a great deal of insight to how the strain affects the reactivity. Additionally, we discovered that although the model Hetero-Diels-Alder adducts did not undergo [2+2] cycloaddition, both exo- and endo-Sulfa-Diels-Alder products, nonetheless, were photochemically active and various products with defined stereochemistry could be produced upon photolysis. In conclusion, we have developed an approach to the encoding and screening of solution phase libraries based on the photorelease of externally sensitized photolabile tags. The encoding tags can be released into solution only when a binding event occurs between the ligand and the receptor, equipped with an electron transfer sensitizer. The released tags are analyzed in solution revealing the identity of the lead ligand or narrowing the range of potential leads. Advisors/Committee Members: Andrei G. Kutateladze, Ph.D..

Subjects/Keywords: Combinatorial; Diversity; Library; Oriented; Photochemistry; Synthesis; Organic Chemistry

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Valiulin, R. A. (2010). Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries. (Doctoral Dissertation). U of Denver. Retrieved from https://digitalcommons.du.edu/etd/943

Chicago Manual of Style (16th Edition):

Valiulin, Roman Askatovich. “Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries.” 2010. Doctoral Dissertation, U of Denver. Accessed June 25, 2019. https://digitalcommons.du.edu/etd/943.

MLA Handbook (7th Edition):

Valiulin, Roman Askatovich. “Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries.” 2010. Web. 25 Jun 2019.

Vancouver:

Valiulin RA. Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries. [Internet] [Doctoral dissertation]. U of Denver; 2010. [cited 2019 Jun 25]. Available from: https://digitalcommons.du.edu/etd/943.

Council of Science Editors:

Valiulin RA. Novel Photochemical Methodologies for Diversity Oriented Synthesis and Screening of Combinatorial Libraries. [Doctoral Dissertation]. U of Denver; 2010. Available from: https://digitalcommons.du.edu/etd/943

2. Cowger, Teresa M. Photoassisted Access to New Polyheterocycles.

Degree: PhD, Chemistry and Biochemistry, 2014, U of Denver

Photoassisted diversity-oriented synthesis holds great promise in its ability to provide rapid access to complex and diverse molecular scaffolds. As it stands, while photochemical techniques have this potential, their implementation in the field of synthetic organic chemistry is very limited. The main goal of this project was to utilize photochemically assisted techniques in the synthesis of a variety of novel polyheterocycles. Initially, we explored the how the strain installed in these polycycles could be harnessed to trigger cationic rearrangements in the framework of the system. This was achieved via the high yield and rapid assembly of a highly strained system containing two oxetanes. This bis-oxetane was derived from a compound containing carbonyl groups endo- to two respective bicyclic olefins which was assembled via a simple Diels-Alder step. The oxetanes were formed in a Paternò-Büchi reaction via excited-state chemistry. The protolytic ring-opening of this bis-oxetane compound afforded two highly unusual polycyclic products that both result from rather complex mechanisms which are proposed in this work. In addition, we were able to elaborate on this rapid Diels-Alder assembly motif by designing a double-tandem [4+2][2+2][4+2][2+2] synthetic sequence which culminates in a complex scaffold containing an oxetane. When subjected to acidolysis, this oxetane affords a complex polycycle with rigidly held pendants rich in heteroatoms. We then intended to study how a bicyclic olefin which also possessed endo-carbonyl groups would perform during irradiation when the length of the tether to the bicyclic system was lengthened. This lengthened tether allowed flexibility in the regiochemistry of the Paternò-Büchi cycloaddition. The regiochemistry was also able to be controlled by the introduction of a methyl group in the tether. The protolytic opening of the two different oxetanes gave polyheterocyclic products with completely different scaffolds that both demonstrate a great increase in complexity of structure relative to the quite simple starting materials. In a departure from Paternò-Büchi, our next design strategies focused on the photo-generation of azaxylylenes via excited-state intramolecular proton transfer. We tethered these azaxylylenes to unsaturated pendants in the hopes that the short-lived intermediate would undergo cycloaddition with these pendants. In this endeavor, we were able to observe both [4+4] and [4+2] cycloadditions, depending on the type of pendant used. We were able to diversify this system by utilizing both carbonyls and imines as the proton abstraction agents, by using thiophene and furan as the unsaturated pendant, and by tethering the pendant to the carbonyl “half” and the aniline “half” of the photoprecursor—demonstrating the tolerance that this system has for a large range of modifications. With the optimization of these methodologies, we aim to pave the way for the incorporation of photochemistry into the toolbox of… Advisors/Committee Members: Andrei G. Kutateladze.

Subjects/Keywords: Cycloaddition; Oxametathesis; Photochemistry; Polyheterocycles; Chemistry; Physical Sciences and Mathematics

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Cowger, T. M. (2014). Photoassisted Access to New Polyheterocycles. (Doctoral Dissertation). U of Denver. Retrieved from https://digitalcommons.du.edu/etd/143

Chicago Manual of Style (16th Edition):

Cowger, Teresa M. “Photoassisted Access to New Polyheterocycles.” 2014. Doctoral Dissertation, U of Denver. Accessed June 25, 2019. https://digitalcommons.du.edu/etd/143.

MLA Handbook (7th Edition):

Cowger, Teresa M. “Photoassisted Access to New Polyheterocycles.” 2014. Web. 25 Jun 2019.

Vancouver:

Cowger TM. Photoassisted Access to New Polyheterocycles. [Internet] [Doctoral dissertation]. U of Denver; 2014. [cited 2019 Jun 25]. Available from: https://digitalcommons.du.edu/etd/143.

Council of Science Editors:

Cowger TM. Photoassisted Access to New Polyheterocycles. [Doctoral Dissertation]. U of Denver; 2014. Available from: https://digitalcommons.du.edu/etd/143

3. Gustafson, Tiffany Priscilla. Development Of Ultra-Sensitive Fluorescence Photoamplification Assays For The Detection Of Molecular Recognition Events.

Degree: PhD, Chemistry and Biochemistry, 2010, U of Denver

During the course of this research a novel method which couples the molecular recognition-triggered photoamplification chain in diaryl ketone adducts of dithiane with a "turn-off" or "turn-on" fluorescence-based assay for the detection of biological targets and ligands, regardless of their nature, through a molecular recognition event has been developed. This research has included several key steps, the most significant being: (1) the design of fluorophore adducts or dyads which recover fluorescence upon photocleavage for a "turn-on" assay and the identification of fluorophores which are quenched upon the photochemical release of a quencher for a "turn off" assay; (2) Optimization of the photochemistry and photoamplification of dithiane adducts of benzophenone as it applies to the development of an ultra-sensitive photoamplified fluorescence assay; (3) implementation of the method in the design and fabrication of chips for ultra-sensitive screening of microarrays, and (4) integration of this microchip assay into a fluorescence based signal transducer for ultra-sensitive detection of molecular recognition events. Proof of concept utilized biotin-avidin recognition, where avidin is coupled to the photochemical sensitizer. Advisors/Committee Members: Andrei G. Kutateladze, Joe Angleson.

Subjects/Keywords: Assays; Fluorescence; Molecular Recognition; Photoamplification

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gustafson, T. P. (2010). Development Of Ultra-Sensitive Fluorescence Photoamplification Assays For The Detection Of Molecular Recognition Events. (Doctoral Dissertation). U of Denver. Retrieved from https://digitalcommons.du.edu/etd/817

Chicago Manual of Style (16th Edition):

Gustafson, Tiffany Priscilla. “Development Of Ultra-Sensitive Fluorescence Photoamplification Assays For The Detection Of Molecular Recognition Events.” 2010. Doctoral Dissertation, U of Denver. Accessed June 25, 2019. https://digitalcommons.du.edu/etd/817.

MLA Handbook (7th Edition):

Gustafson, Tiffany Priscilla. “Development Of Ultra-Sensitive Fluorescence Photoamplification Assays For The Detection Of Molecular Recognition Events.” 2010. Web. 25 Jun 2019.

Vancouver:

Gustafson TP. Development Of Ultra-Sensitive Fluorescence Photoamplification Assays For The Detection Of Molecular Recognition Events. [Internet] [Doctoral dissertation]. U of Denver; 2010. [cited 2019 Jun 25]. Available from: https://digitalcommons.du.edu/etd/817.

Council of Science Editors:

Gustafson TP. Development Of Ultra-Sensitive Fluorescence Photoamplification Assays For The Detection Of Molecular Recognition Events. [Doctoral Dissertation]. U of Denver; 2010. Available from: https://digitalcommons.du.edu/etd/817

.