Physical Sciences and Mathematics Commons^™

Asymmetric Cuh-Catalyzed Reductive Coupling Of Allenamides With Carbonyl And Imine Electrophiles, Stephen Collins

Theses and Dissertations

The carbon scaffold of many drugs and natural products contain multiple stereogenic centers bearing heteroatoms. As a result of this, chemists have long sought methods to efficiently install these multi-heteroatom functionalities. Reductive coupling reactions have been extensively studied over the past decades, and the allylation of carbonyls via the reductive coupling approach has been a key method for generating chiral allylic alcohols. This work utilizes inexpensive Cu for the asymmetric reductive coupling of allenamides with carbonyls or imines to simultaneously install two heteroatoms (either oxygen and nitrogen or nitrogen and nitrogen, respectively) onto the product. These molecules have a polarity …

Ferrocenium Salt Aided Substitution Reactions And Synthesis Of Glycosylated Curcumin Derivatives, Deva Saroja Talasila

Dissertations

Organic synthesis has been significantly advanced with the employment of transition metal complexes. The discovery of transition metal catalysts provided the synthetic community with powerful tools for accelerating reactions and making them more selective and efficient. Many chemical reactions do not happen without a catalyst.

Iron-based catalysts have several advantages for the chemical industry because it is a non-toxic and ecologically friendly metal. Our group previously found that ferrocenium cations with a 3+ oxidation state of iron-catalyzed propargylic substitution reactions at low temperatures. The sandwich structure of ferrocenes allows substituents to be introduced on the cyclopentadienyl rings, which allows for …

Lipophilic Probes For Cellular Ethylene Detection, Morgan R. Brown

Electronic Theses and Dissertations

The structure of ethylene is simple, yet its biological effects are significant. When considering its role in biology it is almost exclusively regarded as a plant hormone. Research on ethylene from plants was progressed by several advancements in analytical instrumentation, from its discovery to elucidation of its signaling pathway. There is currently limited understanding of ethylene’s role in mammals, but evidence suggests that it may be a biomarker for oxidative stress! Additional tools and technology are crucial to study this surprising and important signaling role in mammals. Our group has developed molecular ethylene probes as a strategy to detect ethylene …

Design, Synthesis, And Catalytic Application Of Crystalline Porous Nanomaterials, Zainab Abdullah Almansaf

Graduate Theses and Dissertations

Chapter 1: COFs (covalent organic frameworks) are a new type of microporous crystalline polymer connected by organic units via strong covalent bonds. Due to their well-defined crystalline structures and excellent chemical and thermal stabilities, COF materials are considered promising candidates in applications such as gas adsorption, catalysis, and energy storage.Chapter 2: A new covalent organic framework (COF) based on imine bonds was assembled from 2-(4-formylphenyl)-5-formylpyridine and 1,3,6,8-tetrakis(4-aminophenyl)pyrene, which showed an interesting dual-pore structure with high crystallinity. Postmetallation of the COF with Pt occurred selectively at the N donor (imine and pyridyl) in the larger pores. The metalated COF served as …

Developing Covalent-Organic Frameworks For Protecting Against Radiation, Megan J. Francis

Senior Theses

This research focuses on the development of lightweight, thermostable dual-function materials for secondary radiation protection and sensing by the integration of hydrogen-rich aliphatic chains inside the porous matrix of covalent-organic frameworks (COFs). The main aims of this project are the synthesis of organic linkers for forming a robust porous COF, synthesizing the porous COF through a condensation reaction, the development of hydrogen-rich aliphatic chains, and integration of aliphatic chains into COFs through click chemistry. This manuscript outlines the methodology and development of a novel self-assembled crystalline, porous material engineered to combine the functions of a shield and sensitive dosimeter. The …

End Group Modification Of Linear Dendritic Block Copolymers (Ldbcs), Chinwe Udemgba

Honors Theses

Linear dendritic block copolymers are amphiphilic molecules that consist of a dendritic hydrophilic portion and a linear hydrophobic portion. Its unique ability to self-assemble into spherical nanoaggregates while having the potential to uptake and transport both hydrophilic and hydrophobic drugs makes these polymers an item of interest in regard to the drug delivery field. The synthesis of polyamidoamine-polylactide linear dendritic block copolymers was designed to address the common issues in drug delivery systems, including problems in permeability, solubility, stability, specificity, and retention. Though this linear dendritic block copolymer has previously been synthesized in our lab with cationic amine surface functionalities, …

Synthesis Of A Dd-Π-Aa Organic Dye For Dye-Sensitized Solar Cells, Hope Lovell

Honors Theses

This project investigates the synthesis of a DD-π-AA (dual donor/dual acceptor) organic dye as a potential sensitizer for dye-sensitized solar cells (DSCs). The design of this dye was based off previous research that found dual donor/dual acceptor dyes exhibited promising results when used in a DSC. The donor groups, acceptor groups, and π-bridge were chosen for their stability, ability to absorb in the near-infrared (NIR) region, and intramolecular charge transfer (ICT) abilities.

While many components of the dye were synthesized, the final stages of the synthetic scheme were not completed due to the loss of time from COVID-19. Had the …

Convergent Synthesis Of Anaephene B, Megan Johnson

Honors Program Theses

Many organisms are capable of producing organic compounds as secondary metabolites; these natural products can be quite pharmaceutically and medicinally relevant.1 Typically, the more unique an organism, the more unique its secondary metabolites. Cyanobacteria, an abundant microalgal organism, is capable of producing a myriad of novel natural products.2 The unique photosynthetic and autotrophic properties of cyanobacteria allow for the production of many secondary metabolites, including lipopeptides, amino acids, fatty acids, macrolides, amides, and others.2,3 Staphylococcus aureus is one the most common bacterial infections in the world.4 S. aureus produces a number of metabolites that inhibit host immune responses.4 As a …

Photoassisted Synthesis Of Complex Polyheterocycles Via Rational Design Of Tailored Photoprecursors, Tina Alanna Holt

Electronic Theses and Dissertations

Natural products remain the most common source for drug leads, although diversity-oriented synthesis of unnatural complex molecules is gaining momentum. Our lab has been developing experimentally simple and straightforward approaches to complex molecular architectures via photochemical reactions involving a minimal number of experimental steps. In order to achieve this, photoprecursors were assembled via high yielding reactions. Next, we deployed photoinduced cycloadditions to create complex 3-dimentional structures. Lastly, with this obtained primary photoproduct, post-photochemical transformations were used to further grow its scaffold complexity.

One method to increase scaffold complexity is the [4+2] intramolecular cycloadditions of azaxylylenes, which are developed through standard …

The Application Of Machine Learning In Analyzing Organic Compounds From Nmr Spectral Data, Nicole Maia Powell

Senior Independent Study Theses

Nuclear magnetic resonance (NMR) is used in organic chemistry to identify unknown organic compounds. The data obtained from an NMR spectrometer are typically shown in the form of a spectrum, which is then analyzed by an analytical chemist. The action of analyzing a spectrum, especially one of a large and complex molecule, is a long and tedious process. In this project, Python is used to implement hierarchical clustering on NMR data obtained from an NMR spectrometer at the College of Wooster to explore its application in NMR analysis. MATLAB is used to build a decision tree from the same data, …

Aryne-Guided C-H Functionalization Of Benzenoid Rings Using Diaryliodonium Salts, Aleksandra Nilova

Dissertations and Theses

The benzenoid core is a frequent and irreplaceable component of biologically active molecules. Structure function relationship of these compounds has been broadly analyzed and presented in numerous literature reports. Herein, we augmented existing knowledge by a broad analysis of the benzenoid substitution patterns in small molecule active pharmaceutical ingredients approved by the FDA. Our findings reveal a strong correlation that the most represented substitution patterns are those achieved via S_EAr. Despite the rapid development of methods to functionalize benzenoid rings, the lack of synthetic methodologies to access sterically and electronically unfavorable positions is highlighted. We sought to establish …

Isolation, Structure Elucidation, And Synthesis Of Natural Products From Marine Cyanobacteria, Keren Solomon

Electronic Theses and Dissertations

This thesis describes the isolation, structure elucidation, and synthesis of natural products from marine cyanobacteria. A crude extract from a cyanobacterium collected in Curacao showed selective affinity for the dopamine D₅ receptor in a screen against a panel of CNS receptors. Due to the high similarity of the D₅ and D₁ receptor, to date there are no known ligands that differentiate them. Attempts to purify the compound responsible for this affinity led to the isolation of the known compound caylobolide A. A second extract from a cyanobacterium collected in Panama underwent bioassay-guided fractionation and yielded the novel …

Development Towards An Ethylene Sensing Artificial Metalloenzyme, Mitchell Lee Ellinwood

Electronic Theses and Dissertations

Ethylene (ethene) is the essential ripening hormone for climacteric plants, and consequently its detection and quantification is of considerable interest to the horticulture industry. Its detection however is a non-trivial pursuit, traditionally requiring expensive and inaccessible instrumentation that fail to provide in vivo information about ethylene. A ruthenium based fluorescent probe for the selective detection of ethylene has recently been developed, and it was envisioned that this probe could be made biocompatible by encasing it within a protein scaffold making it an artificial metalloenzyme. To this end biotinylated N-heterocyclic carbenes (NHCs) were synthesized, which can be appended onto the ruthenium …

Studies On The Size And Non-Planarity Of Aromatic Stacking Moiety On Conformation Selectivity And Thermal Stabilization Of G-Quadruplexes, Mandeep Singh

University of the Pacific Theses and Dissertations

Targeting DNA has the advantage over proteins for cancer remediation because of the fewer copies of the ligands required for the desired therapeutic effect. Traditionally, covalent DNA binders like alkylating agents have been used to induce genetic instability through the formation of DNA lesions and strand breaks, leading to cellular apoptosis. The primary drawback of this treatment is the non-specific binding that affects both cancerous and non-cancerous cells. G-quadruplexes are the DNA secondary structures that are present in abundance near the promoter regions of the oncogenes and are involved in the regulation of their activities. A ligand-mediated stabilization of G-quadruplexes …

Thioenamide Synthesis Inspired By Peptide Macrocycles, Joshua Allen Lutz

LSU Doctoral Dissertations

Despite advances in medicine, antibiotic resistance threatens to return once preventable diseases to the human population. The microbisporicins are 24-amino acid antibiotic peptides belonging to the lantibiotic class, which pathogens have been slow to develop resistance. The uncommon post-translational modification S-[(Z)-2-aminovinyl]-D-cysteine (AviCys) is likely crucial to their activity, and appears in a small number of other peptides with compelling biological activities. Total synthesis of an AviCys-containing peptide has eluded the chemical community.

The primary challenge of AviCys synthesis is the construction of a thioenamide functional group. We demonstrate that acid-promoted reactions between an amide and …

The Effect Of Oxidation, Thionation, And Dimerization On The Self-Assembly And Photophysical Properties Of Novel Discotic Materials, Katie M. Psutka

Theses and Dissertations (Comprehensive)

This thesis aims to increase understanding of the relationship between molecular structure and liquid crystalline temperature range by exploring the effects of oxidation, thionation, and dimerization on the self-assembly and properties of novel discotic materials. First, two alkoxy-substituted dibenzanthracenequinones were prepared by oxidation of the corresponding dibenzanthracenes. The quinone induced a liquid crystalline phase in the hexaalkoxy dibenzanthracene derivative, but not in the tetralkoxy derivative. However, both of the resulting materials were un-reactive to any further synthetic modifications that could be used to improve their properties. In comparison, two heteroaromatic dithienoanthracenedicarboximides were successfully prepared, although the addition of the thiophene …

Investigating The Effects Of Pre-Laboratory Videos With Associated Questions On The Performance And Overall Laboratory Experience Of Organic Chemistry Students, Shareef Gamal Mohamed Kotb

Health Sciences Student Work

Background: Teachers struggle communicating ideas to students (Moreno et al, 2001). One of the aspects of teaching that’s most concerning is when students experience cognitive overload: the total effort exerted by working memory to grasp new information (Mayer, et al, 2002). The educational community found that introducing multimedia in learning minimizes cognitive overload (Mayer, et al, 2002). Little research has related to undergraduate chemistry classes, specifically the relationship between organic chemistry pre-laboratory multimedia and student learning. Purpose: The purpose of this capstone is to investigate the subjective efficacy of integrating pre-laboratory videos for lab preparation in an undergraduate organic chemistry …

Photochemical Generation Of Carbenes And Ketenes From Phenanthrene-Based Precursors Part I: Dimethylalkylidene Part Ii: Diphenylketene, Tarini S. Hardikar, Tarini Hardikar

Honors Theses

Previous studies have shown that the photolysis of phenanthrene-based cyclopropyl precursors can generate carbenes. In this work, a novel phenanthrene precursor was synthesized and photolyzed to generate the dimethylalkylidene carbene, which was subsequently trapped by cyclohexene. The car- bene was not prone to an internal rearrangement as some other carbenes are, and instead favored the intermolecular addition reaction. The precursor also underwent a rearrangement via pericyclic processes. A theoretical analysis of the potential energy surface of the system is presented using coupled cluster and density functional methods. Preliminary analysis for the precursor via time-resolved laser flash photolysis (LFP) was performed. …

Synthesis Of A Novel Cox-2 Inhibitor Analog For Pet Scan Imaging, Rebecca Neighbor

Chancellor’s Honors Program Projects

No abstract provided.

Solvent Free Vanadium Mediated Organic Transformations, Garrett Oberst

Undergraduate Honors Thesis Collection

A mixture of vanadium(V) oxide and copper sulfate was used to catalyze oxidative transformations in a variety of organic compounds. Multiple functionalities were tested, including thiols, amines and alcohols. Various transformations were observed resulting in various oxidized products, including coupling reactions. Reactions were performed in a solvent-free environment due to the insoluble nature of vanadium(V) oxide in common organic solvents. Results were analyzed using HNMR and GCMS.

Substrate Specificity Of The Lipn Hydrolase From Mycobacterium Ulcerans, Stephanie Raynor

Undergraduate Honors Thesis Collection

Mycobacterium ulcerans is the causative agent of Buruli ulcer, a tropical skin disease that affects thousands of individuals annually. Recent studies have revealed that lipolytic enzymes are involved in the pathogenicity processes of mycobacterium and could be potential targets for novel antibiotics. LipN is one proposed serine hydrolase in Mycobacterium ulcerans that contains the conserved α/β hydrolase protein fold and utilizes the conserved catalytic traid of serine, histidine, and aspartate/glutamate. The physiological substrate and biological role of LipN from M. ulcerans have not yet been determined. In this study, LipN was cloned into a pET28a plasmid and overexpressed in an …

A Continuous Process Towards The Synthesis Of Quinolones, Stevara N. Clinton

Theses and Dissertations

Abstract

The development of quinolones is described from the first quinolone to the latest fluoroquinolones. Quinolones have generated considerable interest since their discovery because of their antibacterial capabilities. Analogs incorporating the 4-quinolone ring system comprise a largely expanding group of synthetic compounds. The development of antibacterial resistance has created the need for an efficient synthesis of quinolones that can be easily adapted toward the assembly of quinolone based antibacterial drugs.

There are several reported approaches to the 4-quinolone ring system. Many of these methods use expensive starting materials, require the removal of high boiling solvents, or use high temperature conditions …

Enzyme, Cosolvent, And Substrate Interactions In Ple Hydrolysis Reactions And Evaluation Of The Stability Of An Unnatural Glutathione Analogue, Maureen Elizabeth Smith

Dissertations

Prochiral diester malonates have been hydrolyzed in the presence of Pig Liver Esterase (PLE). Several of the diesters produced the respective half-ester in moderate to high enantioselectivity. A series of cosolvent assays were performed to evaluate the ability of the cosolvent to influence the enantioselective outcome of the hydrolysis reactions. Ethanol produced the largest changes in enantioselectivity of all solvents evaluated. The isoenzymes of PLE were also evaluated and provided very different enantioselective outcomes than that of crude PLE. A series of NMR titrations was performed to explore the interactions between the substrates and ethanol cosolvents.

Improvements to our previously …

Photochemical Elimination Reactions That Proceed Via Triplet Excited State Electrocyclic Ring Closures, Himali Devika Jayasekara

Master's Theses (2009 -)

Cage compounds have become an important tool for the study of biological processes. The research focuses on new cage compounds that can unmask functional groups present in biologically important molecules such as proteins, peptides, and oligonucleosides. The project focuses on certain functional groups that are often difficult to release photochemically. These are the thiolate groups present in cysteine residues of proteins and peptides. Thiolate groups are fairly basic leaving groups, unlike the more labile groups such as the carboxylates that are present in proteins and peptides, or the phosphate groups present in nucleosides. The research takes advantage of the ability …

The Synthesis Of A Homologous Series Of Alkyl Lumazines And Their Application To The Dispersion Of Carbon Nanotubes, William P. Kopcha

Master's Theses

In this thesis, the synthesis of a series of alkyl lumazine surfactants (LC_n) is reported. Their application to the dispersion of both CoMoCAT and HiPco single-walled carbon nanotubes (SWNTs) is examined in detail and the thermal stability and chirality selection properties of dispersions made with these surfactants were compared both between themselves and with an alkyl flavin surfactant (FC₁₂). Lumazine alkyl chain length exhibited some control over the quality and the quantity of SWNTs dispersed. LC₁₀ was deemed most appropriate for comparison with FC₁₂ based on considerations of solubility and nanotube individualization. …

Chemical Investigation Of The Antarctic Marine Invertebrates Austrodoris Kerguelenensis & Dendrilla Membranosa And The Antarctic Red Alga Gigartina Skottsbergii, John Alan Maschek

USF Tampa Graduate Theses and Dissertations

The marine realm and, in particular, the Antarctic benthos is largely unexplored and understudied. The chemical investigation reported herein reveals not only the biodiversity, but how that biodiversity manifests remarkable chemical diversity. In our continuing study of the nudibranch Austrodoris kerguelenensis, we have isolated a diverse suite of diterpenoid glyceride esters, palmadorins D - S (2.32 - 2.47), one of which is the first reported halogenated diterpene from a dorid nudibranch. Utilizing genomic data from collaborators, we have investigated the chemical diversity from phylogenetically unique specimens collected in close proximity to one another. Chemical groupings based on comparison of LC/MS …

Kinetics And Stoichiometry Of The Aquation Reaction Of Pentaaquodihalomethyl Chromium(Iii) Ions, Mohammad Javaid Akhtar

University of the Pacific Theses and Dissertations

This study was designed to provide information about the mechanisms of pentaaquodihalomethyl chromium(III) ions (halo chloro, bromo and iodo).

...

Mechanisms based on carbonium ion, carbeno and carbenoid type intermediates are proposed. A mechanism based on the nucleophillic attack (S_N2) of water on the carbon center leading to a metal-formyl type intermediate is suggested as best fitting all the criteria observed in these studies.

(see PDF file for additional Abstract as it includes formulas)

Cyclic 4,6-Oxygen-Acetal Derivatives Of D-Glucopyrano-(2,3: 4',5')-2'-Oxazolidinones., Daniel Vernie Robinson

University of the Pacific Theses and Dissertations

No abstract provided.

3,3-Diphenyl-2-Morpholinone Derivatives Of 2-Amino-2-Deoxy-D-Allose., Ram Babu

University of the Pacific Theses and Dissertations

A new cyclic protective group has been fused to the cis amino alcohol group of benzyl 2-amino-3,5-o-benzylidene-2-deoxyβ-D-Allopyranoside, by way of a unique rearrangements mechanism. To establish the 2-morpholinone structure, chemical studies, such as reduction and acetylation were conducted.

Comparative spectroscopic studies using ir, pmr, and C-13 nmr confirmed the assigned structures.

The 2-morpholinone ring was cleaved by mild alkaline hydrolysis and could be closed again with acetic anhydride in pyridine. An oxazolidinone derivation of benzyl 2-amino-4,6-o-benzylidene-2-deoxyβ-D-allopyranoside was prepared in a quantitative yield by a modification of a known method.

Protective group properties of the oxazolidinone were studied prior to the …

Attempted Synthesis Of 1-Methyl-4-Isopropyl-Hydroxy Bicyclo (3.1.0) Hexane, Kenny Uzoma Acholonu

University of the Pacific Theses and Dissertations

The purpose of this work was to investigate a general synthetic route to 1-Methyl-4-Isopropyl-Hydroxy Bicyclo (3.1.0) Hexane.