Physical Sciences and Mathematics Commons^™

Exploring The Reactivity Of Donor-Acceptor Cyclopropanes And The Synthesis Of (+/-)-Quebrachamine, Huck K. Grover

Electronic Thesis and Dissertation Repository

The development and utility of cyclopropanes is an ever-growing field within organic chemistry. In particular, donor-acceptor cyclopropanes have been used in a vast array of methods to access a variety of different hetero and carbocyclic molecular scaffolds. Recently, we have developed a Zn(NTf2)2 catalyzed tandem reaction consisting of a nucleophilic ringopening of 1,1-cyclopropanediesters by 2-alkynyl indoles followed by a Conia-ene ring closure, resulting in the efficient one-step synthesis of tetrahydrocarbazoles. These adducts may be further elaborated to carbazoles. The scope and limitations of this method were determined along with a mechanistic study into the function of the zinc catalyst. In …

The Development Of Metal-Organic Compounds For Use As Molecular Imaging Agents, Emily J. Simpson

Electronic Thesis and Dissertation Repository

Molecular imaging probes allow for the non-invasive diagnosis of many diseases through the use of a targeting entity for site specific delivery, as well as a signal for external visualization of probe accumulation in the body. This thesis will focus on the development of new approaches to synthesize targeting peptides and chelators for radionuclide incorporation towards the design of novel molecular imaging probes.

Histidine is a tridentate chelator that can be attached in a pendant fashion to a biomolecule in order to coordinate technetium-99m. Once coordinated, it forms a neutral complex that is capable of forming diastereomers with inverted stereochemistry …

The Application Of Novel Donor Acceptor Cyclopropanes In The Synthesis Of Linearly Fused Tricyclic Triazoles, Michelle E. Flisar

Electronic Thesis and Dissertation Repository

Previous work in the Kerr group has shown the success of donor-acceptor cyclopropanes as substrates in a variety of synthetic reactions; this document will apply the use of donor acceptor cyclopropanes in various synthetic reactions. This was done using a 2-substituted 1,1-cyclopropanediester, in the Overman Rearrangement, which has yet to be explored using DA cyclopropanes. Another useful DA cyclopropane is the novel acetylene-bearing donor acceptor diester cyclopropanes which would be synthetically useful in a wide variety of reactions. In particular, the Conia-ene cyclization occurred intramolecularly with this alkyne DA cyclopropane with a large library of nucleophiles. Finally, taking this acetylene-bearing …

The Synthesis And Reactivity Of Novel Donor-Acceptor Cyclopropanes And Progress Towards Pyrrolidine Alkaloids, Michael R. Emmett

Electronic Thesis and Dissertation Repository

The first chapter of this thesis focuses on the synthesis and reactivity of cyclopropane hemimalonates. The cyclopropane hemimalonates can easily be synthesized from 1,1-cyclopropanediesters. The reactivity of cyclopropane hemimalonates with indole under ultra-high pressure conditions leads to ring opened adducts that are complementary to previous research in the Kerr group. The tandem ring opening decarboxylation reaction of cyclopropane hemimalonates led to the synthesis of γ-aminobutyric acid analogues. When an external nucleophile was not present, the cyclopropane hemimalonates could rearrange to form butyrolactones in good to excellent yields. The stereochemical integrity of the cyclopropane hemimalonate is retained through this process, which …

Application Of Mn(Iii) Oxidative Cyclizations To Natural Product Synthesis, Bryan Landschoot

Electronic Thesis and Dissertation Repository

This work begins with a brief review of manganese(III) acetate free radical oxidative cyclization chemistry and its application toward functionalizing nitrogen containing heterocycles. Exploration of a cyclopropane ring opening reaction using indoline, and subsequent manganese(III) cyclization chemistry will be presented as a possible route towards a family of natural products called the flinderoles. Work on the construction of the core of several indole alkaloids from the genus Tabernaemontana, including tronocarpine, chippiine, and dippinine B, will be explored with utilization of manganese(III) cyclizations. Hopes of accessing an advanced common intermediate for each of these natural products will be discussed due …

New Ligands For Lanthanides And Transition Metals Toward Magnetic Resonance Imaging Contrast Agents, Melissa M. Lewis

Electronic Thesis and Dissertation Repository

MRI is a non-invasive technique used in medical imaging. Although contrast agents have been used to enhance the image generated by MRI, it still suffers the major shortcoming of low sensitivity. This has led to a thrust to develop contrast agents that improve sensitivity by relaxivity and CEST. This thesis describes attempts made to aid in the development of sensitive MRI contrast agents.

Chapter 2 investigated pH dependent reversible binding on CEST effect and relaxivity in DO3AM complexes possessing a lone p-nitrophenol arm. Unfortunately, only the Tb³⁺complex had a small CEST signal. T₁ relaxivity of the …

Oxidative Cyclizations Of Tertiary Pentenols And The Synthesis Of Β-Carboline Alkaloids, Geoffrey A. Phillips

Electronic Thesis and Dissertation Repository

This thesis describes the work carried out on two projects. The first chapter of the thesis discusses the application of the second generation Co(nmp)2 catalyst towards the oxidative cyclization of tertiary pentenols through a modified Mukaiyama aerobic oxidative cyclization procedure.

The second chapter describes the progress made towards the synthesis of β-carboline alkaloids. The total synthesis of the alkaloid natural product cyclocapitelline is detailed along with the formal synthesis of the natural product chrysotricine.

Development Of A Gallium-Containing One-Bead One-Compound Peptide Library For The Discovery Of New Molecular Imaging Probes, Fernanda C. Bononi

Electronic Thesis and Dissertation Repository

An eight amino acid one-bead one-compound (OBOC) peptide library, containing a gallium-DOTA complex, was developed in an attempt to overcome common issues associated with the later addition of radionuclides to peptide chains of imaging probes. The further addition of a radionuclide often changes the binding properties of a peptide, as it adds bulk, and possibly charges. MALDI (matrix-assisted laser desorption ionization) tandem mass spectrometry was determined to be the method of choice in order to deconvolute gallium-containing peptide sequences. The library obtained was screened against the breast cancer cell lines MDA-MB-231 and MCF-7. Positive beads were isolated and sequences were …