Organic Chemistry Commons^™

Synthesis Of Putative Microcystin-Lr Degradation Products And Full Macrocyclic Cyanopeptide, Mahesh Kumar Yadab

Wayne State University Dissertations

This thesis primarily focuses on synthesizing fragments of microcystin-LR, which is a natural product, with the aim of establishing them as analytical standards for investigating the biodegradation pathways of MC-LR. Despite of the substantial interest in synthesizing, isolating, and degrading Microcystins over the past few decades, the availability of high-purity microcystin standards at known concentration for quantitative analysis of using LC-MS/MS remains limited. The synthesis of the proposed MC-LR fragments employs the Fmoc/t-Bu protecting group strategy to prevent isomerization. Additionally, novel methods for the total synthesis of N-Boc-Adda are explored, incorporating atom-economic approaches, cross-metathesis, and oxidative boron Heck reactions. The …

High Order Structures Formed By The Natural Aromatic Amino Acids, Gabriel Alexander Kupovics, Zeina Alraawi

Inquiry: The University of Arkansas Undergraduate Research Journal

Excessive concentrations of the natural aromatic amino acids phenylalanine and tyrosine are characteristic of the severe genetic abnormalities known as phenylketonuria (PKU) and tyrosinemia, respectively. Within this context, this feature article authenticates claims that tryptophan can form amyloid-like supramolecular structures in vitro and is the first to propose potential mechanisms of tryptophan self-assembly, including hydrophobic and electrostatic interactions. Thioflavin T (ThT) fluorescence kinetics and transmission electron microscopy (TEM) data suggest the formation of amyloid-like fibrillar structures by natural aromatic amino acids in vitro. Additionally, the propensity of amino acid aggregation increases in the presence of sodium dodecyl sulfate (SDS). The …

Green And Non-Green Extraction Of Eugenol From Cloves Using Steam Distillation, Bek Yuldashbaev

Science University Research Symposium (SURS)

Eugenol is commonly found in many plants such as cloves. It is one of the most used natural anesthetics in dentistry. Indonesia is one of the places indigenous to clove trees. Its people take advantage of the pain numbing properties in cloves to aid their tooth pain. The extraction of eugenol itself can be performed through steam distillation. With the process of distillation, the steam carries the oils extracted from the clove buds and recondenses into a cloudy distillate containing polar and non-polar molecules. To separate the eugenol from the distillate, green and non-green solvents were used. The green solvent …

Interactions Of Bioactive Trace Metals In Shipboard Southern Ocean Incubation Experiments, Shannon M. Burns, Randelle M. Bundy, William Abbott, Zuzanna Abdala, Alexa R. Sterling, P. Dreux Chappell, Bethany D. Jenkins, Kristen N. Buck

OES Faculty Publications

In the Southern Ocean, it is well‐known that iron (Fe) limits phytoplankton growth. Yet, other trace metals can also affect phytoplankton physiology. This study investigated feedbacks between phytoplankton growth and dissolved Fe, manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) concentrations in Southern Ocean shipboard incubations. Three experiments were conducted in September–October 2016 near the West Antarctic Peninsula: Incubations 1 and 3 offshore in the Antarctic Circumpolar Current, and Incubation 2 inshore in Bransfield Strait. Additions of Fe and/or vitamin B₁₂ to inshore and offshore waters were employed and allowed assessment of metal (M) …

Systemic Analyses Of Radiocarbon Ages Of Coexisting Planktonic Foraminifera, Jörg Lippold, Julia Gottschalk, Jean Lynch-Stieglitz, Matthew W. Schmidt, Sönke Szidat, Andre Bahr

OES Faculty Publications

We compare radiocarbon (¹⁴C) ages of coexisting planktonic foraminifera species from sediment cores VM12-107 and KNR166-2-26JPC from the Equatorial Atlantic Ocean for three time periods (Holocene, Heinrich Stadial 1, last glacial maximum). We find a maximum inter-species difference of 1200 ¹⁴C yr. On average, the ¹⁴C ages deviate by ∼300 yr between Globigerinoides ruber and other species. In most cases, this exceeds the analytical uncertainty range of the measurements and thus renders the choice of species for generating age models as important as sample weight. While modern stratified water-column profiles imply an increase in ¹⁴C …

Extracting High-Molecular Weight Dna From Cyanobacteria Using Promega's Wizard® Hmw Dna Extraction Kit With A Modified Protocol, Metis, Megan A. Hept, Lesley H. Greene

Chemistry & Biochemistry Faculty Publications

Extraction of high molecular weight (HMW) DNA for long read sequencing with little to no fragmentation and high purity is difficult to acquire from cyanobacterial species. Here we describe a modified method of extraction using Promega's Wizard® HMW DNA Extraction Kit to acquire high molecular weight DNA from cyanobacterial species. The protocol used in the kit is the “3.D. Isolating HMW DNA from Gram-Positive and Gram-Negative Bacteria” protocol. During a key step in the protocol, the lingering remnants of the mucilage layer of the cyanobacterial species is removed, preventing it from sticking to the DNA pellet produced. This customized modification …

Abiotic Stress Mitigation: A Case Study From 21 Trials Using A Natural Organic Matter Based Biostimulant Across Multiple Geographies, Rachel L. Sleighter, Terry Hanson, David Holden, Kristen M. Richards

Chemistry & Biochemistry Faculty Publications

Crop productivity and yields can be greatly diminished by abiotic stress events including drought, extreme temperatures, excess moisture, and saline irrigation water. Multiple stressors occurring simultaneously can further exacerbate the strain on plants. Various types of biostimulants have been shown to mitigate abiotic stress and here, the results of 21 trials on corn, wheat, soybean, and various high-value crops are discussed in the context of the abiotic stress that either occurred naturally or was experimentally induced. Treatments in these trials included stressed and non-stressed plants, as well as either an untreated control or grower standard fertilizer applications alone and in …

Paek- And Pes-Like Perarylated Phosphonium Ionenes: Synthesis, Thermal Properties, And Conductivity, Samantha Sims

Murray State Theses and Dissertations

Ionic liquids (ILs) are useful for many applications due to the tunability of their characteristic properties making these salts ideal for many applications. To further increase possible areas of application for these materials, some ILs can be incorporated into polymer structures to form poly ionic liquids (PILs) or ionenes. The specific ions used within the material will determine the thermal, mechanical, and chemical stability properties exhibited by the polymer. Adjustments can be made to the ion structures during the synthetic process to influence these observed properties.

Fuel cells, batteries, solar cells, and capacitors, all require materials that can withstand high …

Development And Biological Evaluation Of Selective Small-Molecule Inhibitors Of The Human Cytochrome P450 1b1, Austin Hachey

Theses and Dissertations--Chemistry

The human cytochrome P450 1B1 (CYP1B1) is an emerging target for small- molecule therapeutics. Several solid tumors overexpress CYP1B1 to the degree that it has been referred to as a universal tumor antigen. Conversely, its expression is low in healthy tissues. CYP1B1 may drive tumorigenesis through promoting the formation of reactive toxins from environmental pollutants or from endogenous hormone substrates. Additionally, the expression of CYP1B1 in tumors is associated with resistance to several common chemotherapies and with poor prognoses in cancer patients. However, inhibiting CYP1B1 with small molecules has been demonstrated in cellular and murine model systems to reverse this …

Natural Product Co-Metabolism And The Microbiota–Gut–Brain Axis In Age-Related Diseases, Mark Obrenovich, Sandeep Kumar Singh, Yi Li, George Perry, Bushra Siddiqui, Waqas Haq, V. Prakash Reddy

Chemistry Faculty Research & Creative Works

Complementary alternative medicine approaches are growing treatments of diseases to standard medicine practice. Many of these concepts are being adopted into standard practice and orthomolecular medicine. Age-related diseases, in particular neurodegenerative disorders, are particularly difficult to treat and a cure is likely a distant expectation for many of them. Shifting attention from pharmaceuticals to phytoceuticals and "bugs as drugs" represents a paradigm shift and novel approaches to intervention and management of age-related diseases and downstream effects of aging. Although they have their own unique pathologies, a growing body of evidence suggests Alzheimer's disease (AD) and vascular dementia (VaD) share common …

Design, Synthesis, And Evaluation Of Acetyl Coa Synthetase Inhibitors, Michael Emmett Heene

Graduate Research Theses & Dissertations

Invasive fungal species provide a challenge to the current drug landscape, only partiallymet by approved drugs. The Acetyl Coenzyme Synthetase (ACS) enzymes are an attractive target for antifungal compounds because normal mammalian cells do not rely on ACS for energy metabolism while fungal cells do rely on ACS. This work focuses on the design and synthesis of inhibitors of various fungal ACS enzymes. The first class of inhibitors is based on the 2-aminothiazole scaffold originating from a saturation transfer difference (STD) nuclear magnetic resonance (NMR) study and previous whole-organism assays. Ultimately, the 2-aminothiazole core compounds were found to not be …

Investigation Of Factors Affecting Reverse-Phase High Performance Liquid Chromatography, Rida A. Syed

AUCTUS: The Journal of Undergraduate Research and Creative Scholarship

This study focused on the application of reverse-phase high-performance liquid chromatography (RP-HPLC). RP-HPLC is used for the purification of organic molecules, including pharmaceuticals, natural products, and proteins. We developed a modified version of a United States Pharmacopeia (USP) procedure to separate and purify the chemical components found in Excedrin tablets. The goal was to investigate the relationship between retention time (Tr) and the capacity factor (k') of solutes. By varying the composition of the mobile phase and stationary phase, we experimentally determined the capacity factor of acetaminophen (APAP), caffeine, and aspirin. Our results show that the capacity factor (k') of …

Synthetic Studies Of Dragonamide E And Its Potential Treatment Of Leishmaniasis, Sarah E. Glaesemann

Chemistry Theses

Leishmaniasis is a parasitical infection categorized as one of about twenty Neglected Tropical Diseases. Spread by the female sand fly, it can become very severe if left untreated. Symptoms include skin lesions, which may cause scarring, and mucosal membrane infection, which may lead to facial deformity. The most severe form of leishmaniasis can infect organs such as the liver and spleen, possibly leading to death. The current treatments for leishmaniasis are becoming limited due to an increase in drug resistant parasites. Furthermore, the side effects of these treatments can be very problematic.

In the search for new treatments for tropical …

Renewable Fuels: Molecular Dynamics Investigations Into Pyrolysis Of Methyl Linoleate, Elson Osakpolor Eguaosa

Graduate Theses/Dissertations

With the rapid depletion of the world’s supply of fossil fuels, especially petroleum products, petroleum prices have risen by approximately 800% between the 1970s and now and are projected to continue rising. It is also expected that the world’s consumption of energy will increase commensurate with its growing population. Although biodiesel is a good renewable alternative, it has its limitations including high production costs and poor low-temperature performance. We seek to improve conventional biodiesel with pyrolysis to produce low molecular-weight compounds with high energy densities. Understanding the pyrolysis path on the atomic scale is key as it will allow us …

One-Pot Enol Silane Formation-Allylation Of Ketones Promoted By Trimethylsilyl Trifluoromethanesulfonate, Elizabeth D. Heafner, Xuechun Lin, Alexa Connors, Hanyu Zhong, R. J. Coyle, Yiqi Liu, C. Wade Downey

Chemistry Faculty Publications

Ketones and related substrate classes undergo enol silane formation in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and triethylamine, reaction conditions that also promote the in situ ionization of allyl propionates. When these two processes are performed in one pot, allylation of the ketone is observed in high yields. Aldehydes, esters, and thioesters also serve as enol silane precursors under these conditions. When unsymmetrical allyl cations are employed, regioselectivity depends upon the electronic and steric properties of the substituents.

Synthesis And Evaluation Of Sorbicillinoids, Noah Devolve

Honors Program Theses

Sorbicillinoids are a rich family of natural products that have intrigued and inspired scientists since their initial discovery in 1948. A recent report by Zhang et al. detailed the discovery of several new monomeric sorbicillinoids that are particularly interesting as they show nitric oxide (NO) inhibition in RAW264.7 monocyte cell assays and thus possess potential as anti-inflammatory agents. Based on this information, obtaining more of these novel compounds and establishing a preliminary structure activity relationship (SAR) could be achieved by modulating the substitution pattern on the molecules’ benzene ring and varying the alkyl chain length. To this end, a flexible …

Design, Synthesis, And Biological Evaluation Of Novel Steroidal Analogs: Potential Anticancer Agents, Trevor Ostlund

Electronic Theses and Dissertations

Cancer is a malicious disease with low survivability rates primarily due to lack of reliable treatment options. Treatments are often non-specific for patients, and cancer resistance to treatment is becoming more prevalent as fast as new therapies are created. Previous studies in our laboratory have focused on the Epidermal Growth Factor Receptor (EGFR) and its downstream kinase family members as a key target for cancer. This cascade controls cell proliferation, anti-apoptotic effects, cell regulation, and other survival factors. Additionally, ABC transporters, responsible for efflux of chemotherapeutic material from cells, are key targets to combat drug resistance. We first evaluated a …

Sound The (Smaller) Alarm: The Triphosphate Magic Spot Nucleotide Pgpp, Areej Malik, Megan A. Hept, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

It has recently become evident that the bacterial stringent response is regulated by a triphosphate alarmone (pGpp) as well as the canonical tetra- and pentaphosphate alarmones ppGpp and pppGpp [together, (p)ppGpp]. Often dismissed in the past as an artifact or degradation product, pGpp has been confirmed as a deliberate endpoint of multiple synthetic pathways utilizing GMP, (p)ppGpp, or GDP/GTP as precursors. Some early studies concluded that pGpp functionally mimics (p)ppGpp and that its biological role is to make alarmone metabolism less dependent on the guanine energy charge of the cell by allowing GMP-dependent synthesis to continue when GDP/GTP has been …

Thermotrophy Exploratory Study, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

The question of whether environmental heat energy could be utilized as a source of energy for biological metabolism is the center of this exploratory research. In 1979, this author postulated a hypothesis for the existence of thermotrophs that could isothermally utilize environmental heat energy as a source of their energy on Earth. According to this hypothesis, the thermotrophs could be the first primitive forms of life in the early Earth environment. The chemotrophs and phototrophs that we currently are all well familiar with might have been evolved somehow from the primitive thermotrophs. Furthermore, all the organisms currently regarded as the …

Halogen Bonding Interactions Of Haloaromatic Endocrine Disruptors And The Potential For Inhibition Of Iodothyronine Deiodinases, Craig A. Bayse

Chemistry & Biochemistry Faculty Publications

Halogen bonding (XB) is a potential mechanism for the inhibition of the thyroid-activating/deactivating iodothyronine deiodinase family of selenoproteins through interactions with halogenated endocrine disrupting compounds (EDCs). Trends in XB interactions were examined using density functional theory for a series of polyhalogenated dibenzo-1,4-dioxins, biphenyls, and other EDCs with methylselenolate, a simple model of the Dio active site selenocysteine. The strengths of the interactions depend upon the halogen (Br>Cl), the degree of substitution, and the position of the acceptor. In terms of donor-acceptor energies, interactions at the meta position are often the strongest, suggesting a link to the topology of THs, …