Organic Chemistry Commons^™

Nvrec Subtask 1.2: Thermal Treatment Of Biomass, Curtis Robbins, Eric Ceniceros, Kent Hoekman, Richard Jasoni

Nevada Renewable Energy Consortium Meeting

The second annual Nevada Renewable Energy Consortium meeting took place at UNLV on August 20. The meeting focused on the current three NVREC program areas: Solar, Biomass and Geothermal. Presentations were made by participating entities and a poster session followed.

Acetic Acid Aldol Reactions In The Presence Of Trimethylsilyl Trifluoromethanesulfonate, C. Wade Downey, Miles W. Johnson, Daniel H. Lawrence, Alan S. Fleisher, Kathryn J. Tracy

Chemistry Faculty Publications

In the presence of TMSOTf and a trialkylamine base, acetic acid undergoes aldol addition to non-enolizable aldehydes under exceptionally mild conditions. Acidic workup yields the β-hydroxy carboxylic acid. The reaction appears to proceed via a three-step, one-pot process, including in situ trimethylsilyl ester formation, bis-silyl ketene acetal formation, and TMSOTf-catalyzed Mukaiyama aldol addition. Independently synthesized TMSOAc also undergoes aldol additions under similar conditions.

Synthesis Of Bis-Styrylbenzene Derivatives Via Wittig-Horner Reaction, Joseph K. Wray, Tae Soo Jo, Pradip K. Browmik

Undergraduate Research Opportunities Program (UROP)

Alzheimer’s Disease is now one of the most common diseases affecting the elderly population. Recently, bis-styrylbenzene derivatives have been shown to reduce the formation of Beta-amyloid plaques in the brain which are profoundly correlated with this disease. Finding new biologically active compounds which can reduce or prevent Alzheimer’s Disease has drawn much attention over the past few decades. Georg Wittig, Nobel Prize Winner in Chemistry, 1979.

On-Metal Synthesis Of Some Aryl Substituted Rhenium Η5 Cyclopenta[C] Pyridazyl Complexes, Phenahas Gandu Sriramulu

Masters Theses & Specialist Projects

Heterocyclic organic and organometallic compounds (e.g. polypyrrole) and their derivatives have been of great interest for conductive polymers due to their novel properties and environmental stability as compared to non-aromatic analogs (e.g. polyacetylene). We are interested in synthesizing organometallic pyridazines and rhenium pyridazyl complexes for polymer research. SeveraI5,6-fused ring pyridazines (1,2-CsH3(CRNH)(CRN) have been synthesized and characterized. Additionally, pyridazyl complexes of rhenium were synthesized in three steps beginning from fulvenes 1,2-CsH3(COHR)(COR). On-Metal synthesis and characterization of (Re(CO)3 {1,2- CSH3(CRN)(CRN)}] (R=C6RtOMe, C6RtCI, C4H30) and some off-metal pyridazines are reported here. Our research is focused on synthesis of a variety of 5,6- fused …

Photoreactive Crystalline Quasiracemates, Rebecca C. Grove, Steven H. Malehorn, Meghan E. Breen, Kraig A. Wheeler

Faculty Research and Creative Activity

Rationally designed racemic and quasiracemic sulfonamidecinnamic acids assemble to give hydrogen-bonded dimers with coplanar alignment of neighboring olefins. The quasiracemate phase contains near inversion-related motifs with chemically distinct components forming supramolecular heterodimers that undergo asymmetric photodimerization.

Molecular Orbitals And Organic Chemical Reactions (Book Review), Jeffrey H. Glans

Chemistry & Physics Faculty Publications

Book review by Jeffrey Glans.

Fleming, Ian. Molecular Orbitals and Organic Chemical Reactions. Wiley-Blackwell, 2010, c2009.

ISBN: 9780470746608; 9780470746592 (pbk.)

Synthesis, Kinetic And Photocatalytic Studies Of Porphyrin-Ruthenium-Oxo Complexes, Yan Huang

Masters Theses & Specialist Projects

Macrocyclic ligand-complexed transition metal-oxo intermediates are the active oxidizing species in a variety of important biological and catalytic oxidation reactions. Many transition metal catalysts have been designed to mimic the predominant oxidation catalysts in Nature, namely the cytochrome P450 enzymes. Ruthenium porphyrin complexes have been the center of the research and have successfully been utilized, as catalysts, in major oxidation reactions such as the hydroxylation of alkanes. This study focuses on kinetic and photocatalytic studies of oxidation reactions with wellcharacterized high-valent ruthenium-oxo porphyrin complexes.
The trans-dioxoruthenium(VI) porphyrins have been among the best characterized metal-oxo intermediates and their involvement as …

Controlling Reductive Elimination From Novel I(Iii) Salts Using A Secure Method, Joseph W. Graskemper

Department of Chemistry: Dissertations, Theses, and Student Research

Positron Emission Tomography (PET) is a valuable clinical, research, and diagnostic technique for human and animal organ imaging. The current market for PET in the United States is $500 million per year and is projected to be $5.4 billion per year globally by 2015. To synthesize labeled radiotracers, we are most interested in using ¹⁸F as the isotope of choice because it is a nearly ideal positron emitting radionuclide.

Electron-rich aromatic substrates can be particularly difficult to fluorinate. We show that reductive elimination of I(III) diaryliodonium salts provide increased fluorination of electron-rich aromatic substrates. Modest yields of fluorinated product …

Vibrational Spectroscopic Study Of The 1,3,5,7-Cyclooctatetraene At High Static Pressures, Edward Romano

UNLV Theses, Dissertations, Professional Papers, and Capstones

1,3,5,7-cyclooctatetraene (COT) is a single-ringed hydrocarbon that has not been studied extensively under high static pressures. It was the intent of this study to reveal its high-pressure behavior through its vibrational spectra. To this end, its infrared spectra as a function of pressure were collected at the National Synchrotron Light Source (NSLS) U2A beamline, as well as its Raman spectra over pressure using a micro-Raman spectrometer.

The spectra show the typical stiffening of force constants with increasing pressure for most peaks, particularly those which would theoretically exhibit a mode-softening behavior under hypotheses of molecular planarization and aromatization. Additionally, the data …

Synthesis And Characterization Of Photoactive Amorphous Molecular And Polymeric Pyridinium Materials, Alexi Kamenov Nedeltchev

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pyridinium materials both molecular and polymeric are interesting class of multifunctional electrolytes and polyelectrolytes, which exhibit liquid-crystalline and light-emitting properties. Moreover, their properties could be easily tuned simply by modifying the chemical structures of counterions.

In this dissertation, we described the preparation and analysis of new ionic molecular materials based on bis(pyridinium salt)s and a new class of poly(pyridinium salt)s with various heterocyclic moieties in their backbones with various organic counterions. They were prepared by either ring-transmutation reaction or by metathesis reaction. Their chemical structures were confirmed by FTIR, 1H and 13C NMR spectroscopy and elemental analysis. They had excellent …

2,4,6-Triphenyl­Aniline, Onome Ugono, Stephanie Cowin, Alicia Beatty

Chemistry & Biochemistry Faculty Works

Individual mol­ecules of the title compound, C24H19N, do not participate in hydrogen-bonding inter­actions due to the steric bulk of the phenyl rings ortho to the amine. The dihedral angles between the central ring and the pendant rings are 68.26 (10), 55.28 (10) and 30.61 (11)°.

Rhodium-Catalyzed Hydroboration: Directed Asymmetric Desymmetrization, Judy L. Miska

Department of Chemistry: Dissertations, Theses, and Student Research

Rhodium-catalyzed asymmetric hydroboration in conjunction with directing groups can be used control relative and absolute stereochemistry. Hydroboration has the potential to create new C–C, C–O, and C–N bonds from an intermediate C–B bond with retention of stereochemistry. Desymmetrization resulting in the loss of one or more symmetry elements can give rise to molecular chirality, i.e., the conversion of a prochiral molecule to one that is chiral. Unsaturated amides and esters hold the potential for two-point binding to the rhodium catalyst and have been shown to direct the regiochemistry and impact stereochemistry in asymmetric hydroborations of acyclic β,γ-unsaturated substrates. In …

Degradation Of Chlorophenols In Swine Waste, Srilatha Gangula

Masters Theses & Specialist Projects

Naturally occurring plant derived phenols can be degraded through bacteria in swine waste. Chlorinated phenols, which are not naturally present in the environment, are toxic and generated from industrial activities as such petrochemical, pharmaceutical, plastic, rubber, pesticide, iron, steel, paper production, coal conversion, wood preserving, and cellulose bleaching. Large scale coal gasification and carbonization plants are another source of chlorinated phenols. Although not normally present in the environment, chlorinated phenols are structurally similar to many plant derived phenolics.

It is our hypothesis that bacteria located in swine wastes may also have the ability to degrade chlorinated phenols. Identifying situations (and …

Developing A Biosensor For The Detection Of Bacteria: A Comparison Of Methods For Isolating Bacteria-Specific Antibodies, Scott Allen Walper

Dissertations

The antigen-antibody interaction is known to be a high affinity and highly specific interaction that can readily be used for the detection and identification of biological and chemical agents. These studies were conducted to develop an efficient and cost-effective method of obtaining bacteria-specific antibody molecules for integration into a fielddeployable biosensor. Antigen-binding molecules were obtained both as full-length IgG molecules from a hybridoma cell line and as recombinant single-chain Fv (scFv) antibodies isolated from naïve and immunize libraries. Monoclonal and recombinant antibody systems were compared on the effectiveness of producing new, target-specific molecules; the efficiency of production and purification of …

Library Synthesis Of Anticancer And Antibacterial Agents Via Azide Chemistry, Jianjun Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Various anticancer and antibacterial agents have been synthesized via azide chemistry by taking advantage of carbohydrate. Starting from the synthesis of 14 glycosyl azides, a library of carbohydrate-oxazolidinone conjugates and a library of carbohydrate-cyclopamine conjugates with biological interests were synthesized based on a highly efficient "click reaction" assisted by sonication. Some of the conjugates have improved solubility and enhanced anticancer activity.

A library of neomycin B derivatives with various modifications at the 5" position has been synthesized. Two leads exhibit prominent activity against both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Antibacterial activities were measured when combined with other …

Bacillus Cereus And Bacillus Anthracis Germination Kinetics: A Michaelis-Menten Approach, Helen Luu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bacillus species are rod-shaped, gram-positive bacteria that are capable of producing endospores. In this dormant stage, the endospores can persist in hostile physical and chemical environments. Once conditions become favorable, the spores germinate into actively dividing cells, vegetative cells. Germination is a crucial step for the pathogenicity of the Bacilli in affecting a host organism.

Our study applies mathematical approaches to spore germination to determine whether the binding of one germinant will affect the binding of another germinant. We pursued this approach with two different species, B. cereus and B. anthracis, both pathogenic organisms. B. cereus is a widely known …

The In-Situ Removal Of Menthofuran From Peppermint Oil And Subsequent Reactions Of The Solid-Supported Adduct, Robert Joseph Justice Ii

Dissertations

Menthofuran is an aromatic heterocyclic compound found naturally in the essential oil of Mentha piperita L. or peppermint. Natural peppermint oil may contain between approximately 2 to 8% menthofuran.

Peppermint oil is a complex mixture of over 350 identified chemical compounds; market demands dictate the extent of processing the oil undergoes prior to being introduced into consumer goods. Menthofuran has long been known to readily autoxidize, either alone or within the peppermint oil matrix, leading to a discolored oil with negative organoleptic consequences that adversely affects its commercial viability. Therefore, a facile method for selective removal of menthofuran was developed …

New Chiral Phosphoramidite Complexes Of Iron As Catalytic Precursors In The Oxidation Of Activated Methylene Groups, Pushkar Shejwalkar, Nigam Rath, Eike Bauer

Chemistry & Biochemistry Faculty Works

New phosphoramidite complexes of iron were synthesized and structurally characterized. Reaction of the known chiral phosphoramidites (RO)2PNR’2 (R = binaphthyl, R’ = CH3, 1a; R = binaphthyl, R’ = benzyl, 1b) with [FeBr(Cp)(CO)2] afforded the title compounds [FeBr(Cp)(CO)(1a,b)] (4a,b) in 34 and 65 % isolated yields as mixtures of diastereomers, since both the metal and the ligand are stereogenic. Similarly, reaction of 1b with [Fe(Cp)I(CO)2] in the presence of catalytic [Fe(Cp)(CO)2]2 afforded [Fe(Cp)I(CO)(1b)] (5b) in 81% yield as a mixture of diastereomers. The molecular structures of 4a, 4b and 5 were determined, revealing a pseudo octahedral coordination geometry about the …

The Development Of An Effective Water-Soluble Receptor For Pyrene Derivative Dyes, Ashley Longstreet

Undergraduate Theses and Capstone Projects

A receptor with enhanced water solubility was synthesized from an existing receptor to be used as a pyranine fluorescence quencher in endovesiculation detection assays. The existing receptor consisted of a cyclen core with four protruding arms containing an aryl nitro group at each end. Its poor water solubility limited the accuracy and precision of the endovesiculation assay because the low concentration of receptor did not match the concentration of pyranine. To increase the water solubility, ethoxy groups were attached to the ends of each arm by first selectively reducing the nitro group to an amine with NaBHU4, H2, and a …

Relatin Dissolved Oxygen Concentration To Fish Distribution In Jarecki Lake, Adam Sutton

Department of Environmental Studies: Undergraduate Student Theses

Abstract Water temperature and dissolved oxygen (DO) profiles were measured once every month from mid July to mid February in a relatively deep sand-pit lake in southeast Nebraska. These profiles showed depleted DO concentrations below the thermocline during summer stratification indicating areas fish will likely avoid in summer months. Colder temperatures in fall caused complete mixing of the water column allowing fish to inhabit all depths of the lake. An inverse temperature stratification occurred directly below the ice during winter months as ice cover cooled the surface water to below 4 degrees Celsius. Ice cover also blocked air – water …