Organic Chemistry Commons^™

Latent Cysteine Residues From Polymers Prepared Via Free And Controlled Radical Polymerizations, Douglas Vincent Amato

Master's Theses

One less commonly used “click” reaction is thiazolidine chemistry. Thiazolidine chemistry is a commonly used reaction used in biological systems because the reaction requires the presence of both cysteine (a common amino acid) and an aldehyde or ketone. If cysteine residues could be incorporated into a polymer then a variety of applications could be developed. Polymers containing free thiols (aka thiomers) have developed in the last decade to become great mucoadhesives. If there was a facile route to control the amount of free thiols along the polymer then more fine-tuned and potentially stronger adhesives could be made. For these reasons …

Synthesis And Antifungal Evaluation Of Barbiturate Saponins And Progress Towards Cysteinyl Metal Peptides, Monika Madhav

LSU New Orleans Theses and Dissertations

Invasive fungal infections are a major threat to immune-compromised patients. There is a critical need to develop new antifungal agents because of increasing resistance to the common antifungal drugs.

In the first part of this dissertation, methods for preparation of novel barbiturate saponin as antifungals and their biological activities would be described. Barbiturates and steroidal saponins have shown remarkable antifungal activity in the biological assays. Therefore, attempts were directed to combine the barbiturate with the steroid to give novel antifungal agents. The need for extensive SAR studies and to better understand these compounds efforts were directed to synthesize novel saponin …

Synthesis Of Rhenium And Manganese Pyridazoal Complexes, Jesse Evans

Masters Theses & Specialist Projects

Pyridazines are a heterocyclic aromatic compound containing a characteristic N-N bond that are utilized in many fields, including medicine and electronics. It is this latter field that Dr. Snyder's research group is focused upon. Organometallic compounds are a better conducting material than the current inorganic compounds used in electronics due to better conductance of electricity, lower production cost, and the ability to be formed into thin films. With this in mind, Dr. Snyder's research group has set out to synthesize organometallic compounds for this purpose. Following procedures set forth by Snyder etc, and altered to form an off-metal route, we …

Reactions Of Platinum(Ii) Compounds With Selenium Containing Amino Acids, Stephanie Robey

Masters Theses & Specialist Projects

Platinum(II) anticancer medications essentially react with DNA forming kinks in
the double helix of DNA and causing apoptosis. It has also been noted that these
anticancer medications react with methionine and cysteine in the body. With the new discoveries of selenium containing amino acids including selenomethionine and selenocysteine, new research is ongoing to see what types of products can be formed from these amino acids. Our research reacts [Pt(Met-S,N)Cl₂] ²⁺ with selenomethionine to determine what types of products are produced. Monochelates including [Pt(SeMet-Se,N)Cl₂] ²⁺ have formed two isomers, …

Effects Of Cisplatin Analog Size On The Reaction With Dna Bases, Swathi Nandala

Masters Theses & Specialist Projects

Cancer is the second leading cause of death in the United States. Cisplatin is one of the well-known anti-cancer agents used to treat testicular and ovarian cancers. It mainly binds to the DNA bases, which leads to cell death. The cytotoxic activity of the cisplatin analogs is due to the interaction of platinum with nucleotides like adenine at N₇ or N₁ position and guanine at N₇ position. Guanine is the primary target for cisplatin analogs whereas adenine is the secondary target. Cisplatin analogs, [Pt(Me₅dien)(D₂O)]²⁺[Me₅dien = N,N,N’,N’,N’’-pentamethyl diethylene triamine] and …

Fused Arenes-Based Molecular And Polymeric Materials For Organic Field Effect Transistors, Harista Irugulapati

Masters Theses & Specialist Projects

In the past decade, tremendous progress has been made in organic field effect
transistors. Fused oligothiophenes and anthracene molecules are fascinating
macromolecules having unique optoelectronic properties. These compounds are successfully employed as active components in optoelectronic devices including field effect transistors. Our goal is to design and synthesize conjugated molecular materials, which are highly functionalized through structural modifications in order to enhance their electronic, photonic, and morphological properties. The main desire is to synthesize novel organic fused-arenes having efficient charge carrier mobilities, as well as to optimize optical properties for organic field effect transistors (OFETs). Novel series of fused arene …

Experimenting With Polymer Blend Solar Cells And Active Layer Thickness, Ryan Blumenthal

Physics

Bulk heterojunction organic photovoltaics utilize the electrical characteristics of semi-conductive polymers. These solution processable materials are beneficial because of their low material cost, light weight, and simple fabrication requirements. Our devices employ multiple photoactive polymers, P3HT and PCPDTBT, to absorb photons over a wide spectral range. We optimized various device characteristics including thickness and thermal anneal usage to reach a power conversion efficiency of 3.0% in AM1.5 sunlight. Device performance degrades over time due to atmospheric water and oxygen, prompting us to investigate device packaging to extend cell lifetime for additional testing.

Aerobic Degradation Of Α-, Β-, Γ-Hexachlorocyclohexane By Narragansett Bay Bacterioplankton, Ian M. Rambo

Senior Honors Projects

Hexachlorocyclohexanes (HCHs) are a family of chlorinated organic compounds that were previously used as agricultural insecticides. HCHs are recognized as persistent organic pollutants due to their toxicity, recalcitrant properties, and tendency to bioaccumulate in food webs. Although HCH was first synthesized in 1825, its use was not widespread until the discovery of the insecticidal activity of the γ-HCH isomer in 1942. γ-HCH and its toxic waste isomers α-HCH and β-HCH were banned from production and use by the United Nations in 2009, yet these chemicals still present environmental problems due to their persistence in soils and surface waters. HCHs continue …

Pd-­Catalyzed N-­Arylation Of Amides: Catalyst Development And Scope, Tara Brenner

Renée Crown University Honors Thesis Projects - All

Recent development toward more efficient palladium catalyzed amidation reactions has been driven by mechanistic studies and the development of more efficient ancillary phosphine ligands. This review discusses these developments with regard to substrate scope and the nature of the corresponding catalyst systems. Emphasis will be placed on applications of palladium catalyzed amidation reactions and the synthetic utility of these methods.

Interaction Between Lubricants Containing Phosphate Ester Additives And Stainless Steels, David W. Johnson, Matthew Bachus, John E. Hils

Chemistry Faculty Publications

One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with varying amounts of tricresyl phosphate added as an anti-wear/extreme pressure additive were tested on two different stainless steels at varying temperatures ranging from 300 °C to 350 °C in vacuum. Significant decomposition of the lubricant base-stocks and the phosphate ester additive did occur in most of the trials resulting in the formation of carboxylic acids and phenols. …

Strategic Electronic Property Control Of Self-Assembling Pyrazine-Acenes, Lacie Brownell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Control of electronic properties in organic semiconductor materials is essential for electro-optical applications such as field-effect transistors, light-emitting diodes, and photovoltaic devices. This work is focused on two systems that highlight different approaches for the manipulation of electronic properties: (I) the development of electron-deficient (n-type) materials by selective lowering of E_LUMO and (II) low energy gap materials by controlling both E_LUMO and E_HOMO

To specifically lower E_LUMO, a pyrazine-acene π-platform was extended using electron-withdrawing moieties. These include: pyridine, pyrazine, and benzothiadiazole (system I). From the base pyrazine-acene, the most significant change in E_LUMO of …

Structural And Functional Characterization Of The Ldp3 (Vhz) Protein Tyrosine Phosphatase, Vyacheslav I. Kuznetsov

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protein phosphorylation is as an important regulatory mechanism that controls a large number of physiologically important cellular processes. Proteins are phosphorylated on aliphatic (serine and threonine) as well aromatic (histidine and tyrosine) residues predominantly located on sterically accessible loops. Phosphorylation affects three- dimensional structures of proteins resulting in conformational changes which activate or deactivate enzymatic functions. Because of the ability of protein phosphorylation to modulate a multitude of diverse cellular processes, it became an appealing and promising target for drug therapy.

Attachment of phosphate is accomplished by kinases, whereas the removal of the phosphoryl group is performed by protein phosphatases. …

Further Studies On The Allylic Diazene Rearrangement, Maha Laxmi Shrestha

Graduate Theses and Dissertations

Former graduate student Wei Qi and Professor Matt McIntosh have reported diastereoselective reductive 1,3-transpositions of acyclic alpha, beta-unsaturated tosyl hydrazones to afford substrates with a 1,4-syn or 1,4-anti relationship between alkoxy and methyl groups that proceed via an ADR (Qi, W.; McIntosh, M. C. Org. Lett. 2008, 10, 357; Qi, W.; McIntosh, M. C. Tetrahedron 2008, 64, 7021). In these reports, silica gel was employed to accelerate the reduction. We have found that acetic acid gives the same results with high diastereoselectivity in the reaction. We further optimized the reaction by lowering the amount of catecholborane to 3 eq. Effects …

Molecularly Woven Materials From Metal-Organic Precursors, Gellert Mezei, Jaafar Hachem, Isurika R. Fernando, Natasha R. Wadhwa, Neil C. Hughes

Faculty Research and Creative Activities Award (FRACAA)

No abstract provided.

Electron Transfer In Electrophilic Aromatic Nitration And Nitrosation, Yirong Mo, Zhenhua Chen

Faculty Research and Creative Activities Award (FRACAA)

No abstract provided.

Facile Synthesis Of Silver Nanoparticles Stabilized By Cationic Polynorbornenes And Their Catalytic Activity In 4-Nitrophenol Reduction, Bharat Baruah, Gregory J. Gabriel, Michelle J. Akbashev, Matthew E. Booher

Faculty Articles

We report the facile one-pot single-phase syntheses of silver nanoparticles stabilized by norbornene type cationic polymers. Silver nanoparticles (AgNPs) stabilized by polyguanidino oxanorbornenes (PG) at 5 and 25 kDa and polyamino oxanorbornenes (PA) at 3 and 15 kDa have been synthesized by the reduction of silver ions with NaBH4 in aqueous solutions at ambient temperature. The four different silver nanoparticles have been characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and transmission electron microscopy (TEM) for their particle size distributions. Interestingly, PG stabilizes the silver nanoparticles better than PA as evident from our spectroscopic data. …

Metal-Organic And Supramolecular Architectures Based On Mechanically Interlocked Molecules, Isurika Rosini Fernando

Dissertations

The focus of this work is on mechanically interlocked molecules (MIMs), which have unusual physicochemical and mechanical properties with potential applications in nano-scale/molecular devices and high strength materials.

Rotaxanes, for example, consist of an axle-like molecule threaded through a wheel-like molecule, with bulky groups at the two ends of the axle preventing the wheel from dissociating. The position of the wheel along the axle can be switched in a controllable and reversible manner by applying external stimuli, a feature that might lead to the next generation of computers. Molecularly woven materials (MWMs), another example of molecules with mechanically interlocked features, …

Expulsion Of Leaving Groups From Zwitterionic Intermediates Generated Via Photochemical Electrocyclic Ring Closure Reactions And An Investigation On Tpe Oligomers, Tasnuva Shahrin

Dissertations (1934 -)

Photochemical cleavage reactions have been found widespread use in biological applications that require intracellular photochemical release of biologically active substrates such as peptides, proteins, neurotransmitters, or nucleotide phosphates. The research is to devise photoremovable protecting groups (cage compounds) that can be used to deprotect those biological substrates by irradiation. A number of photocleavage reactions have been developed in recent years which release chlorides, hydroxides, carboxylates, thiolates, and phenolates leaving groups for use in such applications. Nevertheless, photochemical elimination reactions that expel such leaving group anions remain quite uncommon. The cleavage of cage compounds via photolysis requires heterolysis of a bond …

A Novel Algorithm For Validating Peptide Identification From A Shotgun Proteomics Search Engine, Ling Jian, Xinnan Niu, Zhonghang Xia, Parimal Samir, Chiranthani Sumanasekera, Zheng Mu, Jennifer L. Jennings, Kristen L. Hoek, Tara Allos, Leigh M. Howard, Kathryn M. Edwards, P. Anthony Weil, Andrew J. Link

Chemistry Faculty Research

Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) has revolutionized the proteomics analysis of complexes, cells, and tissues. In a typical proteomic analysis, the tandem mass spectra from a LC–MS/MS experiment are assigned to a peptide by a search engine that compares the experimental MS/MS peptide data to theoretical peptide sequences in a protein database. The peptide spectra matches are then used to infer a list of identified proteins in the original sample. However, the search engines often fail to distinguish between correct and incorrect peptides assignments. In this study, we designed and implemented a novel algorithm called De-Noise to …

Spectral Data For "Generation Of Molecular Complexity From Cyclooctatetraene: Preparation Of Optically Active Protected Aminocycloheptitols And Bicyclo[4.4.1]Undecatriene", Mohamed F. El-Mansy, Anobick Sar, Sergey V. Lindeman, William A. Donaldson

Natural Products Synthesis via Organoiron Methodology

Spectral data created in the course of the research project. Supports specific findings in "Generation of Molecular Complexity from Cyclooctatetraene: Preparation of Optically Active Protected Aminocycloheptitols and Bicyclo[4.4.1]undecatriene".

The racemic (6-cyclo-heptadienyl)Fe(CO)₃⁺ cation ((±)-7), prepared from cyclooctatetraene, was treated with a variety of carbon and heteroatom nucleophiles. Attack took place at the less hindered C¹ dienyl carbon and decomplexation of the (cycloheptadiene)Fe(CO)₃ complexes gave products rich in functionality for further synthetic manipulation. In particular, a seven-step route was developed from racemic (6-styryl-2,4-cycloheptadien-1-yl)phthalimide ((±)-9 d) to afford the optically active aminocycloheptitols (−)-20 and …