Chemistry Commons^™

Intermolecular-Trapping Of 1,3-Dialkyl Diaziridines With Hdda-Derived Benzynes, Ramitha Rupasinghe

Undergraduate Research Symposium 2018

The extent to which benzynes react with various trapping agents is an important question in synthetic chemistry due to its versatility to produce products that can be used as pharmaceuticals, dyes and other complex molecules. The hexadehydro-Diels-Alder (HDDA) reaction allows the generation of benzynes in situ which then can be efficiently trapped to synthesize complex products in one step with high yields. Reactions of HDDA - derived benzynes with trapping agents such as thioamides, alcohols, pyrroles, silyl ethers and multifunctional natural products have been studied in previous research. In this research, the reactions of HDDA-derived benzynes with diaziridines is explored …

Evaluation Of Vaporization Enthalpies And Vapor Pressures Of Various Aroma And Pharmacologically Active Compounds By Correlation Gas Chromatography, Daniel Simmons

Theses

Scientists in the pharmaceutical, food, and aroma industries can benefit from reliable thermochemical data. Vaporization enthalpy and vapor pressure data are not available for all compounds. Furthermore, some literature data is conflicting. The goal of this work was to use a method called correlation gas chromatography (CGC) to generate reliable vaporization enthalpy data in instances where other experimental methods are not applicable. Vapor pressures of the targets were also calculated in cases where the required literature data on the standards used in this technique were available.

CGC involves making a standard cocktail that includes a mixture of standards and one …

Chemical Synthesis Of Staphylococcal Oligosaccharides, Satsawat Visansirikul

Dissertations

The Gram positive, cluster forming bacteria Staphylococcus aureus belongs to the family of opportunistic pathogens that may cause blood stream infections when the integrity of skin is broken and the immune system can no longer fight the infection. S. aureus has become one of the most frequent causes of infections in newborns, surgical patients, trauma and burn patients, patients receiving an implant, and dialysis patients with high mortality rates. As a matter of fact, S. aureus has become one of the largest public health and economic impacts amongst all bacterial infectious diseases worldwide. This situation is further complicated by the …

Effect Of Electron Withdrawing And Electron Donating Substituents On The Synthesis Of 1,3,4-Oxadiazoles Using Dibromotriphenylphosphorane, Emily Bliss

Undergraduate Distinction Papers

The goal of this project was to determine the effects that electron withdrawing and electron donating substituents have on the synthesis of 1,3,4-oxadiazoles using a hydrazide starting material and dibromotriphenylphosphorane. This investigation involved the synthesis of hydrazide starting material followed by the synthesis of the oxadiazole with electron donating, withdrawing, or neutral substituents. Through this study, one neutral, three electron donating, two electron withdrawing substituents were investigated. Reactions were analyzed through nuclear magnetic resonance spectroscopy. Neutral electronegative substituents were deemed to be more successful through their percent yield and nuclear magnetic resonance spectroscopy data than both electron donating and withdrawing …

Synthesis Of Novel Agents For The Treatment Of Infectious And Neurodegenerative Diseases, Benjamin Joe Eduful

USF Tampa Graduate Theses and Dissertations

Infectious and neurodegenerative diseases continue to be a major concern worldwide. In spite of the great advances in drug therapy for treating various infectious and neurodegenerative diseases, there is still an urgent need for new and improved drugs due to increasing drug resistance among pathogens, emergence of new pathogens, ease of transmission of infections, ineffective available treatments, toxicity associated with current standard of care, aging populations and the lack of better alternative treatment options.

The first part of this manuscript (chapters 1 - 5) describes the synthesis of novel agents active against Leishmania donovani. According to the World Health Organization …

Biomimetic Studies Of Oxidation Reactions By Metalloporphyrins Through Ligand Effect And Kinetic Studies Of Photo-Generated Porphyrin-Iron(Iv)- Oxocompound Ii Models, Dharmesh J. Patel

Masters Theses & Specialist Projects

High-valent iron(IV)-oxo porphyrins are the central oxidizing species in hemecontaining enzymes and synthetic oxidation catalysts. Many transition metal complexes have been extensively studied as models of the ubiquitous cytochrome P450 enzymes to probe the sophisticated oxygen atom transfer (OAT) mechanism as well as to invent enzyme-like oxidation catalysts. In this work, two metalloporphyrin complexes have been successfully synthesized, and spectroscopically characterized. A new photochemical entry to porphyrin-iron(IV)-oxo derivatives, commonly referred to as compound II models, was also investigated in two porphyrin ligands that differ in electronic and steric environments. As determined by their distinct UV-vis spectra and kinetic behaviors, iron(IV)-oxo …

Secondary Electronic And Solvent Effects On Regiospecific P-Bromination Of Aromatic Systems, Selahaddin Gumus

Masters Theses & Specialist Projects

Bromoarenes are important aromatic building blocks that are commonly used to synthesize various functional compounds in pharmaceutical, agrochemical and related industries.^1,2 This great demand for bromoarenes makes their preparation a widely studied area of synthetic organic chemistry. However, further understanding of the reactivity and regiochemistry of aromatic functionalization reactions is still necessary, as much about the secondary substitution and solvent effects remain unknown.

Resonance Theory is a widely used theoretical model to predict the regiospecifity and reactivity of the bromination of various aromatic compounds.³ The reactivity and regiospecificity of many substituted aromatic compounds is well explained using resonance …

Do Paraben Derivatives Alter T Cell Immunity?, Hailey Kintz

Spring Presentation of Undergraduate Research

T cells immunity is linked to a complex system of cytokines that determine differentiation of naïve T cells into Th1, Th2, Th17, and Treg cells. Estrogen production or periods of elevated production have been correlated with an anti-inflammatory state in which Th2 and Treg cells are up-regulated. Such responses in the immune system are capable of supporting pre-cancerous activity. We are investigating the tie between the xenoestrogen compounds found in cosmetics, parabens, and their ability to regulate T cell immunity. Testing parabens and paraben derivatives with weaker estrogen receptor association will allow for a better understanding of the interplay between …

Organic Chemistry I & Ii (Ccga), Colleen Knight, Leon Gardner, Joseph Lodmell, Ernest Pascoe, Andrea Wallace, Lisa Mcneal

Chemistry Grants Collections

This Grants Collection for Organic Chemistry I & II was created under a Round Seven ALG Textbook Transformation Grant.

Affordable Learning Georgia Grants Collections are intended to provide faculty with the frameworks to quickly implement or revise the same materials as a Textbook Transformation Grants team, along with the aims and lessons learned from project teams during the implementation process.

Documents are in .pdf format, with a separate .docx (Word) version available for download. Each collection contains the following materials:

• Linked Syllabus
• Initial Proposal
• Final Report

Organocatalyzed Synthesis Of Epoxides From Chalcones Utilizing Amino Acids, Sabrina N. Kegeler

Masters Theses

The epoxide functional group is important throughout the chemical and pharmaceutical industries, as well as in nature. In the chemical industry, epoxides are present in resins and fragrances. In the pharmaceutical industry, epoxide-containing compounds are used as intermediates in the manufacturing of drugs. In nature, many natural products contain epoxide groups and are used for medicinal purposes, and for models to create synthetic molecules.

One approach to epoxide synthesis involves the use of an alkene precursor, a base, and an oxidizing agent. This is where my investigations began. The first step was to optimize the epoxidation reaction, examining substrate scope, …

Photoremovable Protecting Groups Based On Electrocyclization With Leaving Group Expulsion Via A Proposed Zwitterion, Gilbert Ndzeidze

Dissertations (1934 -)

The triplet excited state of thioxanthone produced by photolysis undergoes reversible triplet energy transfer with a trimethylene - linked benzothiophene-2-carboxanilide ring system. The ensuing electrocyclic ring closure of the anilide moiety produces a putative zwitterionic intermediate that is capable of expelling leaving groups (LG-) from the C-3 position of the benzothiophene ring. Stern-Volmer quenching studies with cyclohexadiene as quencher furnish the rate constants for the triplet excitation transfer in the forward and reverse directions, which can be expressed as an equilibrium constant K = 0.058. Overall, the rate of triplet excited state reaction becomes K x kr = 5.7 x …

Higher Energy Gap Control Of Fluorescence In Conjugated Polymers, Chien-Hung Chiang

LSU Doctoral Dissertations

Chemo- and biosensors based on fluorescent conjugated polymer benefit from greater detection sensitivity due to amplification of the electronic perturbations produced by analyte binding. This amplification stems from the exciton-transporting properties of conjugated polymers. A conventional design paradigm relies on the analyte binding events which generate sites of lower energy relative to the polymer energy: either fluorescence quenching sites (turn-off sensors) or bathochromically shifted fluorophores (turn-on sensors). In both type sensors, the excitons migrate to the lower-energy site created by analyte binding.

This dissertation primarily focused the investigation of an alternative paradigm when analyte binding creates higher energy gap sites …

Investigating The Synthesis Of 1,3,4-Oxadiazoles Via A Novel Two-Step-One-Pot Cyclodehydration Reaction, Brittney Sowers

Undergraduate Honors Thesis Projects

The given research will investigate synthetic strategies and differential functionalization of 1,3,4- oxadiazoles in hopes of obtaining moderate to high yields. Particularly, the effects of electron withdrawing on oxadiazoles will reveal more information about possible mechanistic details and reaction optimization.

The research in this report is a part of a lager research effort being investigated by Dr. Robin Grote. This research is ongoing and has evolved from its start in the Grote Lab. Previously, the Grote Lab has focused on the formation of a patented heterocycle that contained an amino-pyrazine functional group. Currently, our research has shifted focus to the …

Synthesis And Characterization Of Covalent Adaptable Networks Comprised Of Dynamic Imine And Aminal Covalent Bonds, Albert Chao

LSU Doctoral Dissertations

The dissertation is about the design, synthesis and characterization of materials comprised of covalent adaptable networks (CANs). There are three chapters within this dissertation.

Chapter 1 contains a short overview of conventional thermosets and thermoplastics. A new strategy of combining advantages from thermosets and thermoplastics is utilizing dynamic covalent chemistry (DCC) for material design. Dynamic covalent bonds are able to undergo dynamic exchange which allow the material to adapt to a new state when under stimuli such as stress or strain. Material comprised of such reversible networks is called covalent adaptable networks (CANs). These types of reversible covalent bonds followed …

A Chimeric Nucleobase - Phenylazo Derivative As An Intrinsic Nucleobase Quencher, Gyeongsu Park, Timothy Martin-Chan, Amer El Samm, Robert H.E. Hudson

Western Research Forum

Molecular beacons are important bioanalytical probes which are most often

constructed from a single-stranded oligonucleotide which has been labeled at

opposite termini with a fluorophore and a quencher. When the fluorophore and

quencher are in close proximity, no fluorescence is observed due to FRET

(Fluorescence Resonance Energy Transfer). DABCYL (4-dimethylaminoazobenzene-

4'-carboxylic acid) has been used as a quencher in the molecular beacon to absorbs

excitation energy from a fluorophore and to dissipate the energy as heat. However,

DABCYL is unable to form a base-pair and is conventionally placed as an overhanging

residue. This produces a derivative wherein the chromophore has …

Synthesis Of Oxadiazoles And Examination Of Steric Effects In A Cyclodehydration Reaction, Norah Young

Undergraduate Honors Thesis Projects

The objective of this project is to develop a general substrate scope by testing various steric and electronic effects. This is pursued by developing triphenylphosphine dibromide (PPh3Br2) as an effective cyclodehydration reagent for use with a variety of hydrazides and sterically and electronically different benzoic acids. The two phases of the experiment include assessing yield through a cyclodehydration reaction and comparing that yield to the steric hindrance and molecular structure recorded in different databases. The cyclodehydration reaction uses ortho-substituted benzoic acid with store bought PPh3Br2, and compares those yields to the use of a two step-one pot reaction in place …

Amide Neighbouring Group Effects In Peptides: Phenylalanine As Relay Amino Acid In Long‐Distance Electron Transfer, U. Wille, J. Nathanael, L. Gamon, M. Cordes, Paul R. Rablen, T. Bally, K. Fromm, B. Giese

Chemistry & Biochemistry Faculty Works

Nature uses proteins as medium for long‐distance electron transfer (ET) to carry out redox reactions in distant compartments. This ET occurs either by a single‐step superexchange or through a multi‐step charge hopping process, which uses side chains of amino acids as stepping stones. In this study we demonstrate that Phe can act as a relay amino acid for long‐distance electron hole transfer through peptides. The considerably increased susceptibility of the aromatic ring to oxidation is caused by the lone pairs of neighbouring amide carbonyl groups, which stabilize the Phe radical cation. This neighbouring amide group effect helps to better understand …

Systematic Size Control In The Synthesis Of Zero-Valent Iron Nanoparticles, Grant C. Bleier

Chemistry and Chemical Biology ETDs

A novel synthetic method for the production of highly magnetic, low size-dispersity nanoparticles through reversible magnetic agglomeration is introduced and studied in detail. Initially, a weakly coordinating surfactant (3-octadecyl-2,4-pentanedione) is employed to produce a wide range of nanoparticle sizes ranging from 8 to 20 nm in diameter. The kinetics faced in these reactions by cheap and widely available iron complex precursors can be avoided in this method with the introduction of thermodynamic control, which occurs in the form of a magnetic precipitation event that essentially halts nanoparticle growth. Utilizing this synthetic method, the length of the alkyl chain on the …

Undergraduate Research In Petrology Approached Through Computer Modeling Of Fabric Evolution In Igneous Rocks, Michael C. Leopold, M. J. Bonder, C. W. Holyoke, T. G.M. Krohn, R. V. Amenta

Chemistry Faculty Publications

Undergraduate research is an important part of the curriculum in many geology departments but, in recent years, it has become more difficult to attract students into projects dealing with solid-earth studies due to the limited employment prospects in these areas compared to those in environmental geology. This report describes how petrologic research can be made more attractive to students by an approach using C programming to model crystal growth and fabric development in poly crystalline solids. This topic has broad appeal to students in the other sciences as well as geology, and the computer skills learned have wide practical utility …

Discovery And Development Of A Three-Component Oxidopyrylium Cycloaddition And Its Application Towards Alpha-Hydroxytropolone Synthesis, Michael P. D'Erasmo

Dissertations, Theses, and Capstone Projects

Historically, natural products have provided unique research opportunities and challenges for organic synthesis, chemical biology, and medicinal chemistry due to their molecular complexity and effects on physiological systems. The total synthesis of natural products has not only produced novel reaction methods and strategies capable of efficiently generating complex structural motifs but also granted access to sufficient quantities of otherwise scarce natural product material for clinical evaluation. These synthetic efforts have facilitated the formation of a transdisciplinary partnership between chemistry, biology, and medicine that has been paramount in elucidating the chemical and pharmaceutical utility of natural products. Chapter I of this …

Organic Photochemistry: Remote Delivery Of Reactive Oxygen Intermediates Via A Heterogeneous Approach, Niluksha Walalawela Abeykoon

Dissertations, Theses, and Capstone Projects

Photosensitized oxidation reactions produce a number of intermediates species, which are generated in varying amounts over time. This complexity presents major challenges in the study of oxidation processes. Mechanistic efforts to separate and deliver reactive oxygen intermediates enable their controlled use in processes such as bacterial inactivation. This thesis describes a heterogeneous reaction approach taken to control the generation and delivery of reactive oxygen intermediates. The mechanistic details of photosensitized reactions were elucidated via synthetic, materials, and physical organic techniques to optimize the delivery of reactive oxygen intermediates. This thesis contains six chapters as described below.

Chapter 1 gives a …

A Galactomannoglucan Derived From Agaricus Brasiliensis: Purification, Characterization And Macrophage Activation Via Mapk And Ikappab/Nfkappab Pathways, Yanqing Zhang, Danting Liu, Leilei Fang, Xiaotong Zhao, Aimin Zhou, Junbo Xie

Chemistry Faculty Publications

In this study, a novel galactomannoglucan named as TJ2 was isolated from Agaricus brasiliensis with microwave extraction, macroporous resin, ion exchange resin and high resolution gel chromatography. TJ2 is composed of glucose, mannose and galactose in the ratio 99.2:0.2:0.6. Infrared spectra (IR), methylation analysis and nuclear magnetic resonance spectra indicated that TJ2 mainly contained a b-(1?3) – linked glucopyranosyl backbone. Interestingly, TJ2 significantly promoted RAW264.7 cell proliferation, and was able to activate the cells to engulf E. coli. In addition, TJ2 induced the expression of Interleukin 1b (IL-1b), Interleukin 6 (IL-6), tumor necrosis factor a (TNF-a) and cyclooxygenase-2 (Cox-2) in …

Sphingomyelin And Gm1 Influence Huntingtin Binding To, Disruption Of, And Aggregation On Lipid Membranes, Maxmore Chaibva, Xiang Gao, Pranav Jain, Warren A. Campbell, Shelli L. Frey, Justin Legleiter

Chemistry Faculty Publications

Huntington disease (HD) is an inherited neurodegenerative disease caused by the expansion beyond a critical threshold of a polyglutamine (polyQ) tract near the N-terminus of the huntingtin (htt) protein. Expanded polyQ promotes the formation of a variety of oligomeric and fibrillar aggregates of htt that accumulate into the hallmark proteinaceous inclusion bodies associated with HD. htt is also highly associated with numerous cellular and subcellular membranes that contain a variety of lipids. As lipid homeostasis and metabolism abnormalities are observed in HD patients, we investigated how varying both the sphingomyelin (SM) and ganglioside (GM1) contents modifies the interactions between htt …

Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions, Jiangyue Miao

Electronic Theses and Dissertations

The focus of this research project lies in the development of new methodology in the field of Brønsted acid catalysis enabling rapid synthesis of medicinally relevant compounds. It is foreseen that small molecule sulfonic acids evaluated in this research project will unveil new asymmetric carbon carbon bond forming reactions between substrates hitherto unexplored with Brønsted acid catalysis. It has been established that strong Brønsted acids, such as phosphoric acids, are capable of mediating highly selective transformations operating through unique mechanistic manifolds.

Specific focus for the sulfonic acid catalysts was geared towards asymmetric coupling reactions with synthetically useful precursors such as …

Selective Carbon-Carbon Bond Formation Promoted By Divalent Samarium Reagents, Christopher David-James Aretz

Electronic Theses and Dissertations

Three efficient methods for synthesis of five membered carbocycles, a highly understudied product motif in samarium(II) chemistry, were explored and optimized. These methods utilized simple starting materials to generate linear substrates with functional groups that are reactive towards samarium(II) iodide. The three methods explored were the Reformatsky-aldol, Reformatsky-alkylation, and pinacol cyclizations. The critical discovery for efficient formation of the Reformatsky-aldol and pinacol carbocycles products was the use of lithium bromide. This addition of lithium bromide facilitates easy in situ formation of samarium(II) bromide. The Reformatsky-alkylation cyclization was a newly realized reaction employing samarium enolates. Two of the three methods, the …

Experiential Learning Activity: Biodiesel Inquiry Project, Ji Kim

Open Educational Resources

The activity described herein can be implemented in introductory chemistry and high school chemistry courses. The main goal of the project is to integrate a ubiquitous biodiesel production with experiential learning by providing a community-based project. The students work in groups, research the benefits of using biodiesel over petroleum-based diesel, collect waste cooking oil from home or restaurants, develop simple and cost-effective methods to produce biodiesel.

Identification Of 4-Isopropyl–Thiotropolone As A Novel Anti-Microbial: Regioselective Synthesis, Nmr Characterization, And Biological Evaluation, Mohamed Elagawany, Mohamed Elagawany, Lamees Hegazy, Feng Cao, Maureen Donlin, Nigam Rath, John Tavis, Bahaa Elgendy, Bahaa Elgendy

Chemistry & Biochemistry Faculty Works

We have synthesized and separated tosylated thujaplicin isomers for the first time, and elucidated their structures using 1D, 2D-NMR techniques and X-ray crystallography. The tosylated isomers were used to synthesize 4-isopropyl–thiotropolone and 6-isopropyl–thiotropolone in a regioselective manner. 1H and 13C Chemical shifts of synthesized isomers were fully assigned using several NMR experiments, and their isotropic magnetic shielding was calculated using the GIAO (Gauge Including Atomic Orbitals) method and the B3LYP def2-TZVPP level of theory. The calculated chemical shift values were in a good agreement with the experimental results. The biological activity of all synthesized compounds was evaluated against the fungal …

The Scientific Contributions Of Donald J. Cram, Leiah Carney

Natural Sciences Student Research Presentations

This poster for the Natural Sciences Poster Session summarizes the work of Donald J. Cram in the field of organic chemistry. A Nobel prizewinner in 1987, he is known for his work with hemicarcerands and carcerands, molecular containers which aided in the study of unstable molecules.

Cation Clock Reactions For The Determination Of Relative Reaction Kinetics In Glycosylation Reactions, Philip Adero

Wayne State University Dissertations

This dissertation presents the development of cyclization reactions as clocks for the determination of the molecularity of glycosylation reactions in individual pyranoside systems and extends it to the arabinofuranoside systems. It also describes the development of selective hydrogenolytic cleavage of naphthylmethyl ethers in the presence of sulfides.

The first part of chapter one gives an overview of the significance of glycochemistry and the challenges involved. The second part describes some selected glycosylation methods and extends this to the general mechanistic studies of glycosylation. This is followed by the discussion of the general clock reactions in literature which initiates a further …

Design And Synthesis Of Oligo-(3,5-Dithio-Β-D-Glucopyranoside) As Β-(1→3)-Glucan Mimetics, Xiaoxiao Liao

Wayne State University Dissertations

This dissertation presents the design and synthesis of oligo-(3,5-dithio-β-D-glucopyranoside) as β-(1 → 3)-D-glucan mimetics. The synthesized dimeric, trimeric and tetrameric mimetics were tested for their binding affinities to Dectin-1 and CR3 and their abilities to activate phagocytosis and pinocytosis.

The first chapter gives an introduction of β-(1 → 3)-D-glucan. It gives an introduction about the structure and origin of β-(1 → 3)-D-glucan as well as the immunostimulating effect of natural β-(1 → 3)-D-glucan. The study of interaction between β-(1 → 3)-D-glucan and the receptors leads to a conclusion that the hydrophobicity of β-(1 → 3)-D-glucan is crucial to its immunostimulating …