Application Of The Picoloyl Group In Carbohydrate Chemistry,
2019
University of Missouri-St. Louis
Application Of The Picoloyl Group In Carbohydrate Chemistry, Michael Mannino
Dissertations
Stereocontrol of glycosylation reactions is a constant struggle in the field of synthetic carbohydrate chemistry. The application of the picoloyl (Pico) substituent can offer numerous stereocontrolling avenues. The most popular application is the Hydrogen-bond-mediated Aglycone Delivery (HAD) method that provides excellent selectivity in the glycosylation of a variety of sugar substrates. The HAD method relies on the formation of an intermolecular hydrogen bond between the nitrogen atom of the Pico substituent on the glycosyl donor with the hydroxyl group of the glycosyl acceptor. This interaction provides a facial preference for the nucleophilic attack and hence provides powerful stereocontrol for the …
Analysis Of Dl-Amino Acid Ratios In Eggshells Using Reverse Phase-High Pressure Liquid Chromatography,
2019
Andrews University
Analysis Of Dl-Amino Acid Ratios In Eggshells Using Reverse Phase-High Pressure Liquid Chromatography, Gergana Milkova
Honors Theses
HPLC methodology was developed to determine the concentrations and ratios of D to L amino acids in emu and ostrich eggshells treated with heat at different temperatures . We aimed to determine an internal standard and how ratios were affected under different conditions. An HPLC method was determined that gave consistent retention times and satisfactory enantioseparation . Calibration curves for each amino acid were developed from single and multi-amino acid containing dilution series producing a model that most closely replicates the eggshell-extracted amino acids.
Enantioselective Copper Catalyzed Alkyne-Azide Cycloaddition By Dynamic Kinetic Resolution,
2019
Missouri University of Science and Technology
Enantioselective Copper Catalyzed Alkyne-Azide Cycloaddition By Dynamic Kinetic Resolution, En Chih Liu, Joseph J. Topczewski
Chemistry Faculty Research & Creative Works
The copper(I) catalyzed alkyne-azide cycloaddition (CuAAC), a click reaction, is one of the most powerful catalytic reactions developed during the last two decades. Conducting CuAAC enantioselectively would add a third dimension to this reaction and would enable the direct synthesis of α-chiral triazoles. Doing so is demanding because the two precursors have linear geometries, and the triazole product is a flat heterocycle. Designing a chiral catalyst is further complicated by the complex mechanism of CuAAC. We report an enantioselective CuAAC (E-CuAAC), enabled by dynamic kinetic resolution (DKR). The E-CuAAC is high yielding and affords up to 99:1 er. The E-CuAAC …
Drug Improvement And Design Involving G-Protein Coupled Receptors,
2019
Taylor University
Drug Improvement And Design Involving G-Protein Coupled Receptors, Gabriel Saliba
Chemistry & Biochemistry Student Projects
No abstract provided.
A Chemical Overview Of Opioid Receptors And Their Agonists,
2019
Taylor University
A Chemical Overview Of Opioid Receptors And Their Agonists, Noah Kuszak
Chemistry & Biochemistry Student Projects
This work is a brief overview of the three main opioid receptors and some current research of the ways we can change the agonists and how they affect the opioid receptor pathway.
Dentin Biomodification Potency Of Proanthocyanidins,
2019
Taylor University
Dentin Biomodification Potency Of Proanthocyanidins, David J. Ryker
Chemistry & Biochemistry Student Projects
No abstract provided.
Synthesis And Metalation Of Internally Alkylated Porphyrinoids,
2019
Illinois State University
Synthesis And Metalation Of Internally Alkylated Porphyrinoids, Alissa Nicole Latham
Theses and Dissertations
The mechanism behind alkyl migration in palladium(II) benzocarbaporphyrins was investigated through the synthesis of a 23-methylcarbaporphyrin. It was found that palladium insertion led to methyl group migration to C21 and it is proposed that this occurs through an oxidative addition onto the palladium metal center, followed by a reductive elimination to transfer the methyl to the internal carbon. A similar rearrangement was observed when 23-methylcarbaporphyrin was reacted with [Rh(CO)2Cl]2 and resulted in the formation of a rhodium(III) complex containing a three-membered rhodacycle. The syntheses of rhodium(I) and rhodium(III) derivatives of other carbaporphyrins, including 21- and 22-methylbenzo-carbaporphyrins, were probed and four …
An Improved Synthesis Of Adefovir And Related Analogues,
2019
Department of Physical Sciences, Cork Institute of Technology, Cork, Ireland
An Improved Synthesis Of Adefovir And Related Analogues, Timothy P. O'Sullivan, Et Al
Physical Sciences Publications
An improved synthesis of the antiviral drug adefovir is presented. Problems associated with current routes to adefovir include capricious yields and a reliance on problematic reagents and solvents, such as magnesium tert-butoxide and DMF, to achieve high conversions to the target. A systematic study within our laboratory led to the identification of an iodide reagent which affords higher yields than previous approaches and allows for reactions to be conducted up to 10 g in scale under milder conditions. The use of a novel tetrabutylammonium salt of adenine facilitates alkylations in solvents other than DMF. Additionally, we have investigated how …
The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid,
2019
University of Kentucky
The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman
Chemistry Faculty Publications
The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O2(aq)], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10–200 mM PA at pH 1.0 in water covering the relevant range 0 ≤ [O2(aq)] ≤ 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. …
Synthesis Of A Sulfur Variant For Treatment Of Trypanosomiasis,
2019
University of Nebraska at Omaha
Synthesis Of A Sulfur Variant For Treatment Of Trypanosomiasis, Carlos Vera-Esquivel
UNO Student Research and Creative Activity Fair
Previous work in our lab has found diphenyl ether benzylamines showed a successful response with a micromolar concentration of our lead compound to treat the deadly Trypanosamiosis rhodesience. Furthermore, mammalian cell lines saw promising resistance towards damages. The goal of this study was to synthesize a diphenyl thio benzylamine variant. This variant was more active toward T. b. rhodesience but showed more toxicity to both rat 10 (IC50 mM) and human cell lines (HFF, HC-04, U-2 OS, and HEK293). The selectivity index (ratio of toxicity to activity in the same concentration units (SI)) …
Facile And Efficient Synthesis Of Thiosemicarbazone Derivatives With Functionalized Pendant Amines.,
2019
University of Louisville
Facile And Efficient Synthesis Of Thiosemicarbazone Derivatives With Functionalized Pendant Amines., Anna E Davis
College of Arts & Sciences Senior Theses
Bis-thiosemicarbazones are an important class of ligands for the synthesis of transition metal complexes with applications in medicine and electrochemistry.1,2 Among the most studied of these complexation ligands is diacetyl-2,3-bis(N4-methyl-3-thiosemicarbazone) (denoted as ATSM, 1, Figure 1).2,3 Derivatives of 1 with various amines in place of the methylamine of ATSM have previously been reported, including diacetyl (N4-methylthiosemicarbazone-N4′-dimethylthio-semicarbazone) (denoted as ATSM/DM, 2).4 In this work, we pursue the development of a library of ATSM derivatives with a variety of functionalized pendant amines with a range of electronic and steric …
Seasonal Origins Of Soil Water Used By Trees,
2019
ETH Zurich
Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source …
Metal-Assisted Hydrolysis Reactions Involving Lipids: A Review,
2019
University of Richmond
Metal-Assisted Hydrolysis Reactions Involving Lipids: A Review, Dominique E. Williams, Kathryn B. Grant
Chemistry Faculty Publications
This report covers major advances in the use of metal ions and complexes to hydrolyze ester and phosphate ester lipid bonds. These metal-based Lewis acids have been investigated as catalysts to isolate fatty acids from biological sources, as probes to study phospholipid bilayer properties, as tools to examine signal transduction pathways, and as lead compounds toward the discovery of therapeutic agents. Metal ions that accelerate phosphate ester hydrolysis under mild conditions of temperature and pH may have the potential to mimic phospholipase activity in biochemical applications.
Metrics And Methods Used To Compare Student Performance Data In Chemistry Education Research Articles,
2019
University of Washington - Seattle Campus
Metrics And Methods Used To Compare Student Performance Data In Chemistry Education Research Articles, Michael R. Mack, Cory Hensen, Jack Barbera
Chemistry Faculty Publications and Presentations
Quasi-experiments are common in studies that estimate the effect of instructional interventions on student performance outcomes. In this type of research, the nature of the experimental design, the choice in assessment, the selection of comparison groups, and the statistical methods used to analyze the comparison data dictate the validity of causal inferences. Therefore, gathering and reporting validity evidence in causal studies is of utmost importance, especially when conclusions have real policy implications for students and faculty, among other stakeholders. This review examines 24 articles that reported quantitative investigations of the effect of instructional interventions on performance-based outcomes conducted within undergraduate …
Ring Expansion Of Alkylidenecarbenes Derived From Lactams, Lactones, And Thiolactones Into Strained Heterocyclic Alkynes: A Theoretical Study,
2019
Swarthmore College
Ring Expansion Of Alkylidenecarbenes Derived From Lactams, Lactones, And Thiolactones Into Strained Heterocyclic Alkynes: A Theoretical Study, N. N. Thu Le, J. Just, J. M. Pankauski, Paul R. Rablen, D. M. Thamattoor
Chemistry & Biochemistry Faculty Works
Strained cycloalkynes are of considerable interest to theoreticians and experimentalists, and possess much synthetic value as well. Herein, a series of cyclic alkylidenecarbenes—formally obtained by replacing the carbonyl oxygen of four-, five-, and six-membered lactams, lactones, and thiolactones with a divalent carbon—were modeled at the CCSD(T)/cc-pVTZ//B3LYP/6-311+G** and CCSD(T)/cc-pVTZ//CCSD/6-311+G** levels of theory. The singlet carbenes were found to be more stable than the triplets. The strained heterocyclic alkynes formed by ring expansion of these singlet carbenes were also modeled. Interestingly, the C≡C bonds in the five-membered heterocycles, obtained from the rearrangement of β-lactam- and β-lactone-derived alkylidenecarbenes, displayed lengths intermediate between formal …
Carbohydrate Polymers As Controlled Release Devices For Pesticides,
2019
Ateneo de Manila University
Carbohydrate Polymers As Controlled Release Devices For Pesticides, Soma Chakraborty, Maria Cleofe Neri-Badang
Chemistry Faculty Publications
Controlled release technology addresses problems associated with excessive use of toxic agricultural chemicals. This paper reviews the studies on the use of carbohydrate polymers as controlled release matrices for pesticides. Alginates, starch and its derivatives, chitosan, carboxymethylcellulose and ethylcellulose are some of the natural polymers discussed in this review. The advantages and disadvantages of these polymeric systems as well as the factors that affect pesticide release are presented. A discussion on the polymers’ encapsulation efficiency and release profile is also included, which will aid future researchers in identifying the suitable formulation for controlled release of pesticides. Combination of two polymers, …
Bisthioether Stapled Peptides Targeting Polycomb Repressive Complex 2 Gene Repression,
2019
CUNY Graduate Center
Bisthioether Stapled Peptides Targeting Polycomb Repressive Complex 2 Gene Repression, Gan Zhang
Dissertations, Theses, and Capstone Projects
Interactions between proteins play a key role in nearly all cellular process, and therefore, disruption of such interactions may lead to many different types of cellular dysfunctions. Hence, pathologic protein-protein interactions (PPIs) constitute highly attractive drug targets and hold great potential for developing novel therapeutic agents for the treatment of incurable human diseases. Unfortunately, the identification of PPI inhibitors is an extremely challenging task, since traditionally used small molecule ligands are mostly unable to cover and anchor on the extensive flat surfaces that define those binary protein complexes. In contrast, large biomolecules such as proteins or peptides are ideal fits …
Synthesis And Evaluation Of Novel Iodine-124 Labeled Nucleoside Analogs As Pet Imaging Agents To Predict Response To Gemcitabine Therapy,
2019
CUNY Graduate Center
Synthesis And Evaluation Of Novel Iodine-124 Labeled Nucleoside Analogs As Pet Imaging Agents To Predict Response To Gemcitabine Therapy, Kishore Kumar Gangangari
Dissertations, Theses, and Capstone Projects
Gemcitabine (gem) is a nucleoside analog that is used to treat pancreatic cancers (PaCa), which have dismal prognosis and low survival rate. Though gem is used as first line of treatment for PaCa, the response rate is quite low (~30%). Currently, there is no a priori way to determine a responder from a non-responder to gem therapy either invasively or non-invasively. Any biomarker that can act as a prognostic indicator of gem response will greatly aid in selecting responsive patients to gem therapy and provide alternative options such as Folfirinox or other treatments to resistant patient population. Amongst various known …
Photo-Induced Remote C-H Functionalization And New Thioglycoside Donor Development For O-Glycosylation,
2019
Louisiana State University and Agricultural and Mechanical College
Photo-Induced Remote C-H Functionalization And New Thioglycoside Donor Development For O-Glycosylation, Shaofu Du
LSU Doctoral Dissertations
This dissertation focuses on the method development of C-H functionalization using photo-redox catalysis and the synthesis of new thioglycoside donors towards O-glycosylation. Chapter 1 describes the remote Csp3-H functionalization using photo-redox catalysis. The site-selective and high-yielding conversion of unreactive aliphatic C-H bonds has been a challenge for organic chemists for many years. In this work, inert C-H bonds were successfully converted to more useful C-C, C-N, and C-O bonds via hydrogen atom transfer (HAT), radical translocation and polar crossover. This mechanistic manifold was enacted by visible-light irradiation of o-diazoniaphenyl alkyl sulfones in the presence of Ru(bpy) …
Refinement Of Production Grade Biodiesel,
2019
GCSU
Refinement Of Production Grade Biodiesel, Campbell Axt, Robert B. Hughley Jr., Sydney Ninneman, Jillian Turner
The Corinthian
The modified Burton method for the thermal hydrogen-cracking of peanut oil has been investigated in McGill Research Group since 2009. The successful and reliable production of biodiesel has been achieved since 2014. A hydrocarbon with a viscosity similar to Production Grade Diesel will work in modern diesel engines. The current product has a viscosity significantly lower than production grade diesel. The starting material has a viscosity significantly higher than Production Grade Diesel. Current research is investigating methodologies to mix starting material and product to achieve target viscosity.
