Physical Sciences and Mathematics Commons^™

Bioorthogonal Reactions: Synthesis And Evaluation Of Different Ligands In Copper Catalyzed Azide-Alkyne1,3-Dipolar Cycloaddition (Cuaac), Zainab Abdullah Almansaf

Graduate Theses and Dissertations

The Copper CatalyzedAzide-Alkyne1,3-Dipolar Cycloaddition (CuAAC) reaction has unique features that qualify it to be one of the best click reactions. Its applications have been shown in different aspects and for multiple purposes. The oxidative degradation of biological systems (labile proteins and live cells) is, however, generally recognized as the major problem when using this reaction in living systems. Reactive oxidation species can be easily produced in the presence of copper(II), ascorbate and air, and this is the main cause of toxicity. However, the uses of ligands have shown a major impact on reducing copper toxicity, protecting Cu(I) from the redox …

Direct Attachment Of 4-Hydroxybenzoic Acid Polymers And Capture Agents To Flat Sheet And Microdialysis Membranes For Improved Mass Transport, Sarah Jane Phillips

Graduate Theses and Dissertations

Microdialysis (MD) sampling is a diffusion-based separation method which has the ability to sample any analyte that can diffuse across the semi-permeable membrane. However one challenge for MD is that for soluble proteins greater than 10 kDa, the relative recovery (RR) using a 100 kDa MD probe is between 1-5%.1 There are two major barriers that lead to these low recovery values - nonspecific adsorption (NSA) and poor solute mass transport. To overcome these two barriers, the modification of PES-based MD membranes has been initiated by laccase. Previous researchers have used laccase to modify PES flat sheet and hollow fiber …

Investigation Of The Interaction Of Dimeric Ruthenium Complexes With Cytochrome B5, Christopher Dain Rupar

Graduate Theses and Dissertations

Photoreactive complexes to study the kinetics of electron transfer of proteins have been in use for a long time. It has always been speculated that complexes bind near the heme or the electron transfer reaction would not occur. But it is unkown exactly how the complex interacts with the protein. The structural, thermodynamic, and kinetic properties of rat liver microsomal cytochrome b5 were investigated when bound to ruthenium dimer complexes. Heteronuclear Single Quantum Coherence studies support a dynamic binding model of a dimer Ru complex bound near the protein’s heme involving residues H39, E44, G42, V61, G62, and H63. The …

Studies In The Asymmetric Synthesis Of The C21-C34 Fragment Of The Natural Product, Antascomicin B, Brian Lee Walker

Graduate Theses and Dissertations

This dissertation describes studies in the asymmetric synthesis of the C21 – C34 fragment of the natural product, antascomicin B. Antascomicin B is structurally related to FK506, binds strongly to FKBP12, yet does not shown immunosuppressive activity. Small ligand FKBP12 binding complexes were shown to have potent neuroprotective and neuroregenerative properties in mouse models of Parkinson’s disease. The highlighted chemical reactions include an asymmetric transfer hydrogenation (ATH), Ireland-Claisen rearrangement (ICR), directed hydrogenation and allylic diazene rearrangement.

Mechanism Of Rapid Electron Transfer Reactions Involving Cytochrome Bc1, Cytochrome C And Cytochrome Oxidase, Jeremy Erik Durchman

Graduate Theses and Dissertations

Electron transfer between mitochondrial proteins complexes represents the primary means by which living things acquire the requisite energy for survival. The coupling of electron transfer to proton translocation creates an electrochemical gradient that drives the synthesis of highly energetic compounds such as ATP. The purpose of these studies is to measure rates of electron transfer and elucidate the important governing factors in the redox events involving cytochrome bc1, cytochrome c and cytochrome oxidase. Using rapid initiation of redox events triggered by laser flash excitation of ruthenium compounds, and strategically monitoring unique spectral properties of these proteins in the visible region …

Two Studies: Stereoselective C-C Bond Formations Of N-Boc-Piperidines Using Selected Organolithiums And Visible-Light-Mediated Synthesis Of Fused Indolines Using Tethered Styrenes, Scott Alan Morris

Graduate Theses and Dissertations

Chemists worldwide have accepted the challenge of developing methods to access a variety of compounds as single enantiomers, including the use of enzymes, chiral auxiliaries, and resolutions. In particular, dynamic resolutions offer a unique way to access chiral compounds using a few controllable steps, including the variation of both time and temperature. Many groups have implemented this methodology to generate various polysubstituted pyrrolidines and piperidines, which are substructures ranking high on the list of nitrogen–containing pharmaceuticals.

The Gawley group revealed a catalytic dynamic resolution (CDR) of N–Boc–piperidine using a chiral ligand. Impressively, the chemistry was tolerant of a variety of …

[3+2] Annulation Of Cyclopropylanilines With Alkynes Under Photocatalysis, Theresa Ha Nguyen

Graduate Theses and Dissertations

Over the past decade, pharmaceutical industries have prioritized their focus on discovering new innovative drugs, yet the syntheses are often either inefficient or the approach of environmental sustainability presents a great deal of concern. Moreover, the methodology developments for amine syntheses have continued to flourish due to their important role and wide use in pharmaceutics. Yet their syntheses often lack sustainability and efficiency. Synthetic chemists have continued to explore potential innovative avenues for conducting chemical reactions more effectively and efficiently. One of the most abundant, renewable natural resources is solar energy and to harvest, use, and store it directly is …

The Large-Scale Synthesis And Asymmetric Hydrosilylations Of Cuiphet, A C2-Symmetric N-Heterocyclic Carbene, Elizabeth Suzanne Spahn

Graduate Theses and Dissertations

CuIPhEt is a C2-symmetric N-heterocyclic carbene catalyst used in the asymmetric hydrosilylation of a variety of prochiral ketones with good yields and selectivities. The large-scale, five-step synthesis of this carbene has been devised. The second step of the synthetic plan includes a double asymmetric hydrogenation of a 1,1-diaryl alkene—a traditionally difficult transformation. The procedure for the use of CuIPhEt in asymmetric hydrosilylations has been optimized and used on both the originally published substrate scope and new compounds. This protocol for the hydrosilylation has been applied in a 10 g reduction to create an intermediate for use toward the total synthesis …

Synthesis Of Microgel Polymers As Catalysts, Hannah N. Miller

Chemistry & Biochemistry Undergraduate Honors Theses

New developments in organic synthesis show promise in achieving the best catalytic properties for the hydrolysis of glycosidic bonds through microgel polymers and transition metal complexes. A monomer mix of ethylene glycol dimethacrylate, butyl acrylate, and styrene form miniemulsion polymers after sonication and exposure to UV light. Gravimetrical analysis is used to determine the most suitable polymerization conditions by performing experiments at varying pH values, temperatures, monomer amounts, initiator amounts, and lamp heights. The final data show that the best polymerization conditions are a pH of 10.50 at 0°C with a high monomer ratio, 20% initiator amount, and a lamp …

Improving Photocatalytic Activity By Appending A Quinone To Ruthenium Polypyridyl Complex, Amy N. James

Chemistry & Biochemistry Undergraduate Honors Theses

By converting natural light energy into chemical energy, chemists are studying ways to take advantage of clean energy. The rising precedence of “green chemistry” has led to academic interest in the activity of photocatalysts and harnessing visible light in an efficient, accessible, and safe manner. Photochemistry is an upcoming and fascinating field of study that has made significant progress, but also has great potential for future work. By utilizing light as a natural energy source, many reaction processes in chemistry can be viewed with a new perspective. Ru(bpy)₃²⁺ is one of the most widely used photocatalysts. An efficient …