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Central Washington University

Chemistry

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Full-Text Articles in Physical Sciences and Mathematics

Contra-Thermodynamic Halolactonization Of Lactam-Tethered 5-Aryl-4(E)-Pentenoic Acids For The Flexible And Stereocontrolled Synthesis Of Fused Lactam-Halolactones, Timothy K. Beng, Claire Borg, Morgan J. Rodriguez Oct 2022

Contra-Thermodynamic Halolactonization Of Lactam-Tethered 5-Aryl-4(E)-Pentenoic Acids For The Flexible And Stereocontrolled Synthesis Of Fused Lactam-Halolactones, Timothy K. Beng, Claire Borg, Morgan J. Rodriguez

All Faculty Scholarship for the College of the Sciences

Halolactonization of alkenoic acids enables the construction of oxygen-heterocycles via intramolecular halonium-induced nucleophilic addition. Although the literature is currently inundated with halolactonizations of 5-aryl-4(E)-pentenoic acids that predictably afford the 6-endo cyclization adducts, methods that reliably alter the innate regioselectivity bias to instead deliver the thermodynamically less favored 5-exo cyclization products are relatively rare. Here, we attempt to bridge this gap and have found mild conditions for contra-thermodynamic halolactonization of lactam-tethered 5-aryl-4(E)-pentenoic acids that lead to the formation of trans-fused lactam-γ-lactones. The natural proclivity for these 5-aryl-4(E)-pentenoic acids to undergo 6-endo cyclization is overridden and 5-exo-trig cyclization predominates. The success of …

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Stereocontrolled Access To Δ-Lactone-Fused-Γ-Lactams Bearing Angular Benzylic Quaternary Stereocenters, Timothy K. Beng, Morgan J. Rodriguez, Claire Borg Jun 2022

Stereocontrolled Access To Δ-Lactone-Fused-Γ-Lactams Bearing Angular Benzylic Quaternary Stereocenters, Timothy K. Beng, Morgan J. Rodriguez, Claire Borg

All Faculty Scholarship for the College of the Sciences

C-fused γ-lactam-lactones are resident in several bioactive molecules, including anticancer agents such as omuralide. In this embodiment, we report mild conditions for the catalytic halolactonization of lactam-tethered 5-aryl-4(E)-pentenoic acids. The use of dichloromethane as the solvent and Ph3PS as the catalyst led to predominant 6-endo-trig cyclization and furnished the trans-fused-γ-lactam-δ-lactones. The transformation is modular, regioselective, chemoselective, and diastereoselective. The γ-lactam-δ-lactones bear angular quaternary benzylic stereocenters, which is noteworthy since the presence of a quaternary carbon in bioactive small molecules often promotes an element of conformational restriction that imparts potency, selectivity, and metabolic stability. The …

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Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth Jan 2018

Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth

All Master's Theses

Fine atmospheric particulate matter (PM2.5) emitted during the combustion of fossil and biomass fuels is known to adversely affect human health. While the underlying mechanisms are thought to be driven by the generation of reactive oxygen species (ROS), specific particle characteristics responsible for this detrimental effect are not well understood. In this research, the quantitative determination of the biologically relevant antioxidant, glutathione (GSH), was optimized for use as an indicator of oxidative stress to shed light on relevant particle characteristics. This was accomplished via fluorescent spectroscopy for GSH determination by way of reaction with o-phthalaldehyde (OPA), a …

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A Direct, Early Stage Guanidinylation Protocol For The Synthesis Of Complex Aminoguanidine-Containing Natural Products, Christopher E. Malmberg, Stephen Chamberland Sep 2016

A Direct, Early Stage Guanidinylation Protocol For The Synthesis Of Complex Aminoguanidine-Containing Natural Products, Christopher E. Malmberg, Stephen Chamberland

All Faculty Scholarship for the College of the Sciences

The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important structural element found in many complex natural products and pharmaceuticals. Owing to the continual discovery of new guanidinecontaining natural products and designed small molecules, rapid and efficient guanidinylation methods are of keen interest to synthetic and medicinal organic chemists. Because the nucleophilicity and basicity of guanidines can affect subsequent chemical transformations, traditional, indirect guanidinylation is typically pursued. Indirect methods commonly employ multiple protection steps involving a latent amine precursor, such as an azide, phthalimide, or carbamate. By …

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Kinetic Decay Of A Polymer/Ink Complex As An O2 Indicator, Becca Hoene Jan 2016

Kinetic Decay Of A Polymer/Ink Complex As An O2 Indicator, Becca Hoene

All Master's Theses

Indicator inks are an important part of the continued consumption of packaged goods. This thesis is focused on understanding the kinetics and reaction mechanism for a unique indicator ink that is based upon the oxidation of indigotetrasulfonate (ITS) encapsulated in the polyelectrolyte poly(diallyldimethylammonium chloride) (polyDADMAC). Sodium bisulfite (NaHSO3) was used as the initial oxygen scavenger and to drive the reduction of the ITS. Studies were predominantly done in solution phase through the dilution of the ink systems. Fluorescence spectroscopy was the primary method used to determine the kinetic decay rates and interaction between the ITS dye molecules and …

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Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key Jul 2006

Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key

All Faculty Scholarship for the College of the Sciences

Within open‐ocean regions where excess macronutrients are present, phytoplankton growth is limited by the bioavailability of iron supplied to these areas primarily within atmospheric aerosols of crustal origin. However, processes that control the abundance of biologically accessible iron in these aerosols are largely unknown. Here we show that dissolution of ferrihydrite, a surrogate iron(oxy)hydroxide phase found in atmospheric waters, is enhanced in the presence of methanesulfinic acid (MSIA, CH3SO2H, a dimethylsulfide (DMS) oxidation intermediate) in laboratory irradiation experiments with aqueous suspensions that simulate marine aerosol particles. The increased release of soluble Fe(II) is attributed to a …

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Water Quality Assessment: A Hands-On Approach To Environmental Education, Tracy Lynn Royse Jan 2004

Water Quality Assessment: A Hands-On Approach To Environmental Education, Tracy Lynn Royse

All Graduate Projects

A water quality assessment lab manual has been created to assist secondary educators using the HACH water quality testing kits. It consists of ten chemical tests, a geological survey and a biological assessment largely based upon Washington State University's lab format and the Walla Walla County Conservation District's water study protocol. The lab manual also contains safety guidelines, a scoring rubric and an action plan research project. The environmental approach to science education used in the lab manual meets the Essential Academic Learning Requirements adopted by the Washington State Commission on Student Learning as well as the National Science Education …

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A Kinetic Study Pertaining To The Enzymatic Reduction Of Pyruvate By Lactate Dehydrogenase, Ronald Floyd Tienhaara Dec 1971

A Kinetic Study Pertaining To The Enzymatic Reduction Of Pyruvate By Lactate Dehydrogenase, Ronald Floyd Tienhaara

All Master's Theses

The reduction of pyruvate as catalyzed by lactate dehydrogenase has been studied by monitoring the oxidation of DPNH (diphosphopyridine nucleotide) at 340 nm. The kinetic investigation was carried out in phosphate buffer at 25° C. Since pyruvate exists in equilibrium with the enolized and hydrated forms, a kinetic analysis was devised to determine the nature of the true substrate for the enzymatic process. Also, a comparative study was made involving two isozymes of lactate dehydrogenase. The catalytic effectiveness of these isozymes was studied as a function of pH and substrate concentration.

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Synthesis And Characterization Of Some Dioxane Complexes, James Donald Satterlee Aug 1971

Synthesis And Characterization Of Some Dioxane Complexes, James Donald Satterlee

All Master's Theses

The boron trifluoride, tin (IV) fluoride and titanium (IV) fluoride complexes with 1,4-dioxane have been prepared and studied using infrared techniques. The compositions of the complexes have been determined and correspond to the 1:1 adducts in the case of the tin and titanium compounds. The boron trifluoride adduct is a 2:1 (acid:base) adduct. Infrared spectra in the region 1300 cm.-1 to 550 cm.-1 are given and the effects of coordination upon the ligand vibrations are described.

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A Kinetic Analysis Of The Iodination Of Pyruvic Acid And Pyruvate Esters, Mohamed M. Fahmi Hegazi Aug 1971

A Kinetic Analysis Of The Iodination Of Pyruvic Acid And Pyruvate Esters, Mohamed M. Fahmi Hegazi

All Master's Theses

In the present work the relative rates of iodination of pyruvic acid and ethyl and methyl pyruvate have been compared at 25.0° C. These studies allow the determination of the respective free energies of activation for these processes. Measurements have also been carried out at various temperatures to determine the enthalpies and entropies of activation for the spontaneous and base catalysed iodinations of these pyruvate systems. The present thesis also includes a comparison of the solvent deuterium isotope effects associated with the spontaneous rate of iodination of pyruvic acid and the alkyl pyruvates. Also, the catalytic rate coefficients associated with …

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The Enzymatic Oxidation Of Aldehydes By Xanthine Oxidase, Duane Beal Gregory Jun 1970

The Enzymatic Oxidation Of Aldehydes By Xanthine Oxidase, Duane Beal Gregory

All Master's Theses

As early as sixty years ago, the existence of an enzyme from mammalian tissues which catalyzed the oxidation of xanthine and hypoxanthine was recognized. The name given the enzyme was derived from its earliest recognized action, hence xanthine oxidase. Although little is known about the biological functions of the enzyme, the high affinity shown for xanthine and hypoxanthine may indicate that these are the most significant substrates biologically.

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Acid-Base Catalysis Of The Enolization Of Acetone, Janet Louise Larson Jan 1970

Acid-Base Catalysis Of The Enolization Of Acetone, Janet Louise Larson

Undergraduate Honors Theses

Measurements are reported on the rate of iodination of acetone at 25°c in arsenate, phosphate, and diethylmalonic acid buffers at a constant ionic strength of 0.2. Unlike earlier results which indicate that in acetic acid buffer the expression for the reaction velocity contains an appreciable kinetic term involving the product of the concentrations of acid and anion, it has been found from the present work that such a term is experimentally immeasurable for the above mentioned buffers. This finding coupled with the relatively powerful catalysis by the phosphate and arsenate dianions could imply the simultaneous participation of these species in …

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The Reaction Of Ethylenediamine With Cobalt (Ii) Perchlorate And Oxygen In Dilute Aqueous Solutions, Robert J. Karmy Aug 1968

The Reaction Of Ethylenediamine With Cobalt (Ii) Perchlorate And Oxygen In Dilute Aqueous Solutions, Robert J. Karmy

All Master's Theses

Cobalt (II) perchlorate was reacted with ethylenediamine and molecular oxygen. Various mole ratios of ethylenediamine to cobalt (II) were oxygenated and studied by photometric, potentiometric, conductometric, magnetic susceptibility, freezing point depression, electron spin resonance and cobalt (II) extraction methods. The fact that the complex was brown in color, diamagnetic, contained ethylenediamine to cobalt to oxygen in a mole ratio of 4:2:1 was confirmed. The complex underwent elation to form a polymeric species with excess base. The complex could not be oxidized to a green paramagnetic complex by reacting it with sodium peroxydisulfate, potassium bromate, bromine or chlorine. Ammonia was added …

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Preparation Of Phenylsulphur Chloride Tetrafluoride, Dennis T. Sauer Aug 1968

Preparation Of Phenylsulphur Chloride Tetrafluoride, Dennis T. Sauer

All Master's Theses

The reaction of C6H5SF3, CSF and C12 was studied under a variety of conditions. The reaction run in the presence of a trace of water yielded C6H5SO2F and C1C6H4SO2F. The reaction run in stainless steel at 170°C yielded an amber solid believed to be a polymer with the empirical formula C6H3.67SF2. Chlorination of a C6H5SF3-CSF mixture in monel at 220°C yielded a yellow liquid tentatively identified as a mixture of the new species C6H5SF4C1, FC6H4SF4C1 and C1C6H4SF4C1.

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A Comparative Study Of Inductive Influence On The Hydrolysis Of Beta-Thioglucopyranosides By Beta-Thioglucosidase And Beta-Glucosidase, Robert W. Miller Jr. Jan 1967

A Comparative Study Of Inductive Influence On The Hydrolysis Of Beta-Thioglucopyranosides By Beta-Thioglucosidase And Beta-Glucosidase, Robert W. Miller Jr.

All Master's Theses

A series of phenyl-D-thioglucopyranosides were prepared and characterized in order to determine the absolute specificity of the .B-thioglucosidase and B-glucosidese enzyme systems toward the th1oglucosidic bond. The specificity of B-glucosidase of almond emulsin toward oxygen linkage seems to be absolute, since no hydrolysis was observed by this enzyme system toward the phenyl-D-thioglucopyranosides. The P-th1oglucosidase system was found to hydrolyze only two of the thioglucopyranosides. It was apparent that only where the electron-attracting substituents in the phenyl group were strong enough to greatly weaken the strength of the sulfur linkage, as in the case of the nitro group, would there be …

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