Mechanistic Investigations Of The Iron(Iii)-Catalyzed Carbonyl-Olefin Metathesis Reaction, 2018 Loyola University Chicago
Mechanistic Investigations Of The Iron(Iii)-Catalyzed Carbonyl-Olefin Metathesis Reaction, Susan Phan
Iron(III)-catalyzed carbonyl-olefin ring-closing metathesis represents a new approach toward the assembly of molecules traditionally generated by olefinˆ’olefin metathesis or olefination. Herein, we report detailed synthetic, spectroscopic, kinetic, and computational studies to determine the mechanistic features imparted by iron(III), substrate, and temperature to the catalytic cycle. These data are consistent with an iron(III)-mediated asynchronous, concerted [2+2]-cycloaddition to form an intermediate oxetane as the turnover-limiting step. Fragmentation of the oxetane via Lewis acid-activation results in the formation of five- and six-membered unsaturated carbocycles.
The Enzymatic Activity And Inhibition Of Dape Encoded N-Succinyl-L,L-Diaminopimelic Acid Dessucinylase, 2018 Loyola University Chicago
The Enzymatic Activity And Inhibition Of Dape Encoded N-Succinyl-L,L-Diaminopimelic Acid Dessucinylase, Tahirah Heath
The bacterial enzyme DapE is a hydrolase in the late stage of the mDAP/lysine biosynthetic pathway that catalyzes the hydrolysis of N-succinyl-L,L-diaminopimelic acid (L,L-SDAP) to succinic acid and L,L-diaminopimelate (DAP). The product DAP is ultimately converted to m-DAP and then to lysine which is used in the construction of proteins, whereas for humans, lysine is an essential amino acid obtained through diet. DapE has been shown to be conserved across many strains of bacteria. The m-DAP produced through the succinylase pathway is used by both gram negative and gram-positive bacteria in the construction of the essential ...
Design And Application Of Porous Organic Frameworks For Recyclable, Heterogeneous, Transition-Metal Catalysis, 2018 Iowa State University
Design And Application Of Porous Organic Frameworks For Recyclable, Heterogeneous, Transition-Metal Catalysis, Brian Schumacher
Graduate Theses and Dissertations
In this thesis, heterogeneous frameworks are explored and examined for their use in recyclable catalysis. Specifically, metal-organic-frameworks (MOFs) and covalent-organic-frameworks (COFs) containing bidentate nitrogen ligands are pursued for their use in transition metal catalysis.
Palladium(II)-functionalized COF (Pd@TpBpy COF) is demonstrated as a recyclable, heterogeneous catalyst for palladium-catalyzed conjugate addition of arylboronic acids to β,β-disubstituted enones to form ketone products containing all-carbon quaternary centers in aqueous 50 mM NaTFA as the reaction medium. A wide range of arylboronic acids are added to various β,β-disubstituted enones in moderate-to-high yields.
Pyridine oxazoline derivatives are designed and synthesized for ...
Intramolecularly Enhanced Receptors With Unusual Binding And Molecularly Imprinted Nanoparticles As Nanoreactors And Sensors, Xiaoyu Xing
Graduate Theses and Dissertations
The conformational flexibility of a receptor is usually considered unfavorable to binding, due to the entropy loss upon binding. Inspired by the biological receptor with intra-receptor secondary binding sites which can strengthen guest binding, two series of artificial receptors with similar structures were constructed: pseudo crown ethers with aromatic donor/acceptor groups and aromatic tweezer molecules with carboxylic acids. When the guest binding was weakened by the solvents, i.e., pseudo crown ethers bound with cations in polar solvents and aromatic tweezers bound with counterparts in non-polar solvents, intra-receptor interactions became stronger and contributed to the guest binding. The overall ...
Manipulating Push-Pull Systems To Probe Biology And Photochemistry, 2018 Iowa State University
Manipulating Push-Pull Systems To Probe Biology And Photochemistry, Andrea Thooft
Graduate Theses and Dissertations
Photochemistry and photophysics are two rapidly expanding areas in science. The first part of this dissertation looks at the synthesis of a new fluorescent probe based on the well-known fluorophore nitrobenzoxadiazole (NBD). We synthesized a new derivative using the nitrile functional group as the electron withdrawing group. Our results showed our fluorophore (CBD) displayed redder emission than the nitro counterpart, and an emission range that was similar to that of the sulfonamide containing derivatives. Additionally CBD displayed extensive solvatochromic properties: high quantum yield and bluer emissions in nonpolar solvents while low quantum yield and redder emissions as the solvent polarity ...
Synthesis And Catalytic Testing Of A Proline Functionalized Amphiphilic Block Copolymer, 2018 Eastern Michigan University
Synthesis And Catalytic Testing Of A Proline Functionalized Amphiphilic Block Copolymer, Eric Firestone
Master's Theses and Doctoral Dissertations
Catalysts are reagents used to reduce the amount of energy that a reaction needs to execute, allowing it to proceed at a higher rate while not being consumed. The use of catalyst functionalized amphiphilic copolymer allows easier recovery of the catalyst at the end of the synthesis and allows for the reaction. In water, under appropriate conditions, the amphiphilic block copolymers will form micelles and allow the reaction to occur on the interior of the micelle. The synthesis of amphiphilic copolymer with a hydrophobic O-methacryloyl-trans-4- hydroxy-L-proline and methyl methacrylate end and a hydrophilic acrylic acid end was characterized. The polymer ...
Photoredox-Mediated Metal-Free C–H Alkylation And Dual Catalysis, 2018 University of Pennsylvania
Photoredox-Mediated Metal-Free C–H Alkylation And Dual Catalysis, Jennifer K. Matsui
Publicly Accessible Penn Dissertations
Over the past decade, a resurgence of interest in photo-induced electron transfer has resulted in a new class of organic transformations. The ability to harness over 60 kcal/mol of visible light energy to activate redox-labile substrates—via the intermediacy of a photoredox catalyst—has enabled reactions under extraordinarily mild conditions compared to alternative two-electron modes of activation.
Recent research efforts have broadened the scope of trifluoroborate coupling partners, employed 1,4-dihydropyridines (DHPs) in mono- and dual-catalytic manifolds, and accessed new chemical space via C–H functionalization pathways. First, the development of alkyltrifluoroborates as latent radicals for C–H alkylation ...
Part I: Vanadium–Catalyzed Asymmetric Oxidative Coupling Of Phenols And Hydroxycarbazoles And Its Mechanistic Study Part Ii: Total Synthesis Of Chaetoglobin A Part Iii: Ligand Evolution To Drive Reaction Discovery Part Iv: Oxidative Coupling Of 3-Oxindoles To Construct Quaternary Centers, 2018 University of Pennsylvania
Part I: Vanadium–Catalyzed Asymmetric Oxidative Coupling Of Phenols And Hydroxycarbazoles And Its Mechanistic Study Part Ii: Total Synthesis Of Chaetoglobin A Part Iii: Ligand Evolution To Drive Reaction Discovery Part Iv: Oxidative Coupling Of 3-Oxindoles To Construct Quaternary Centers, Houng Kang
Publicly Accessible Penn Dissertations
Part I: The axially chiral biaryl motif is found in many natural products as well as in ligands for catalysis such as 1,1’-binaphthol. Formation of axially chiral compounds was accomplished by means of the asymmetric oxidative coupling, which has proven to be both an efficient and environmentally benign synthetic method. Interests toward an effective asymmetric oxidative coupling of simple phenols, which are challenging substrates because of relatively high oxidation potential and regioselectivity issues, have arisen due to a lack of corresponding methods. After many efforts to design and modify the catalyst scaffold, we found that a monomeric vanadium ...
Tuning Of Environmental Probes, 2018 Iowa State University
Tuning Of Environmental Probes, Paige Bouc
Graduate Theses and Dissertations
This thesis describes two projects focusing on (1) the investigation of benzoxadiazole chromophore and (2) new methods for solid phase microextraction.
This thesis investigates how the diazole ring in nitrobenzoxadiazole affects environmental sensitivity. We developed a novel synthesis of isobenzofurans using anthranilic acid derivatives. The use of benzyne and bioorthogonal chemistry is used to achieve our isobenzofuran derivatives.
This thesis will address two different ways in which to improve solid phase microextraction methods. By utilizing a novel cross linker and reverse addition fragmentation chain transfer (raft) polymerization we are able to control polymerization to give us more consistent polymers ...
Syntheses Of Azepinoindole Alkaloids Cimitrypazepine, Fargesine And Hyrtioreticulins C & D, 2018 West Virginia University
Syntheses Of Azepinoindole Alkaloids Cimitrypazepine, Fargesine And Hyrtioreticulins C & D, Ganesh Ghimire
Graduate Theses, Dissertations, and Problem Reports
The Watanabe-Cenini-Söderberg reductive N-heterocyclization has emerged as a powerful tool for the synthesis of a variety of functionalized indoles. Söderberg’s elaboration of this methodology has been utilized as a late-stage cyclization protocol for the synthesis of azepinoindole alkaloids, a class of natural products characterized by an azepane skeleton fused with an indole ring. Short syntheses of the naturally occurring azepino[5,4,3-cd]indole alkaloids, cimitrypazepine, fargesine, and the diastereomeric hyrtioreticulins C & D have been completed starting from commercially available tetra-substituted benzene derivatives. The key azepinoindole core in each case was assembled via an intramolecular Mizoroki-Heck reaction ...
Design And Synthesis Of Oligo-(3,5-Dithio-Β-D-Glucopyranoside) As Β-(1→3)-Glucan Mimetics, 2018 Wayne State University
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- ...
The Scientific Contributions Of Donald J. Cram, 2018 Parkland College
The Scientific Contributions Of Donald J. Cram, Leiah Carney
Natural Sciences Poster Sessions
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.
Selective Carbon-Carbon Bond Formation Promoted By Divalent Samarium Reagents, 2018 University of Denver
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 ...
Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions, 2018 University of Denver
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 ...
Assessing Specificity Of Indazole Derivatives As Inhibitors To Cyp2e1, 2018 Ouachita Baptist University
Assessing Specificity Of Indazole Derivatives As Inhibitors To Cyp2e1, Hannah Hart
Metabolism of drugs in the human body can yield both desirable and undesirable results. Some of these side-effects are due to drug-drug interactions, drug-diet interactions, or lack of drug specificity. The enzymes that drugs attack are structurally selective and complex; therefore, many drugs are very general in structure and could possibly react with a variety of enzymes. Indazole has been used as a backbone for several drugs as it has the general structure that may react with most P450s. To determine a derivative, or a group of derivatives, of indazole that may be reactive only with cytochrome P450 2El (CYP2El ...
Detection And Determination Of Food Residues In Native American Pottery, 2018 University of Northern Iowa
Detection And Determination Of Food Residues In Native American Pottery, Katherine A. Plotzke
Honors Program Theses
The purpose of this research was to develop a new method of analyzing organic residues left on Native American pottery using linear Raman spectroscopy. Native American pottery was replicated using terra cotta and maple syrup was boiled in each of the pots using boiling stones. The pottery shards were then analyzed using Raman spectroscopy. Shards of pottery with maple syrup residue were compared to the standards and the syrup residue was not only detected, but also matched to compounds in the instrument library. Typically, the study of Native American pottery has been done in a variety of different ways, many ...
Formulation And Characterization Of Lipogels As A Tunable Delivery Scaffold, 2018 University of Massachusetts Amherst
Formulation And Characterization Of Lipogels As A Tunable Delivery Scaffold, Celia Homyak
Nanomedicines within the clinic commonly utilize lipid-based scaffolds due to their aqueous assembly and non-covalent dual-guest loading capabilities. Nevertheless, poor stability in vivo and premature guest release remains a challenge with these systems. Polymeric nanomaterials are a popular alternative due to their good stability in vivo with controllable guest release. A caveat to polymeric scaffolds though, is the excess synthetic effort involved for non-covalent dual-drug encapsulation. Benefit lies in harnessing advantages of lipid and polymeric materials via lipid-polymer hybrid scaffold. Such materials have promise due to their dual-encapsulation and dual-stimuli-sensitive characteristics. The need to better understand these materials led us ...
Light-Harvesting And Light-Responsive Materials For Optoelectronic And Biological Applications, 2018 University of Massachusetts Amherst
Light-Harvesting And Light-Responsive Materials For Optoelectronic And Biological Applications, Youngju Bae
In photodynamic therapy, several critical standards are required of photosensitizers including high singlet oxygen quantum yield, biocompatibility in dark, and long term photochemical stability. In addition, current PDT systems lack active targeting strategies to tumor cells, and instead mainly rely on the natural distribution of PS in the body following injection and application of near-infrared light treatment in the tumor region. This thesis describes a series of BODIPY-based molecules that were designed, synthesized and studied as photosensitizers with high singlet oxygen generation capacity through utilizing the heavy atom effect. Additionally, aqueous solubility and active targeting capability were introduced by photosensitizer ...
Design And Synthesis Of Stimuli-Responsive Polymeric Nanogels Towards Therapeutic Translation, 2018 University of Massachusetts Amherst
Design And Synthesis Of Stimuli-Responsive Polymeric Nanogels Towards Therapeutic Translation, Mallory R. Gordon
In the application of delivery of therapeutics, nanostructures of various composition have been employed due to their capacity to act as a host for lipophilic payloads. Advances in the synthetic preparation, size, morphology, and chemical or physical characteristics of polymers have impacted their development and versatility. A detailed understanding of polymeric nanoparticle host-guest properties is crucial to their practical translation to specific delivery applications. Further, these features must be highly tailorable to overcome biological barriers, stably encapsulate their therapeutic contexts, and exhibit payload release selectively in the target environment. In this dissertation, we aim to rationally design polymeric nano-scale assemblies ...
Investigation Of The Exraction Processes And Performance Properties Of Kudzu Fibers, 2018 University of Alabama
Investigation Of The Exraction Processes And Performance Properties Of Kudzu Fibers, Bahrum Prang Rocky, Virginia Wimberley
International Textile and Apparel Association (ITAA) Annual Conference Proceedings
While kudzu was introduced into the Southeastern United states for soil erosion and increase of land fertility, the plant has become unmanageable and is rapidly spreading to Canada. Japanese traditional craftsmen extract long, white fibers by labor intensive practices not feasible for 21st century commercial fiber production. This research investigated extraction by boiling, retting or fermentation, enzymatic combinations, and mild chemical processes. Two types of fibers were resultant- soft fibers and compact woody fibers. These fibers types were assessed for microscopic visual appearance, elemental analysis using EDAX SEM, and tensile strengths for the four extraction processes. In all extraction cases ...