Chemistry Commons^™

Synthesis Of Structurally Diverse Molecular Scaffolds Enabled By Protected Oxyallyl Cations, Joshua Andrew Malone

LSU Doctoral Dissertations

This dissertation focuses on the synthesis of diverse molecular scaffolds through the use of protected oxyallyl cation intermediates. Chapter One provides background on the generation and applications of oxyallyl and silyloxyallyl cations, while focusing on the direct nucleophilic capture of theses intermediates to generate functionalized ketones and silylenolates. Chapter Two depicts our approach to generate six-membered silyloxyallyl cations through the use of mild Brønsted acid activation. Regioselective nucleophilic capture of these intermediates successfully produced diverse a,a’-substituted silylenol ethers enabled by polar solvent and residual water.

Chapter three details strategies to generate 1,4-dicarbonyl compounds, focusing on the capture of cationic intermediates …

Identification Of Degradation Products Formed From Glycerol And Terpenes In Aromatherapy Vaporizers, Alisha Ortiz

University Honors Theses

Degradation chemistry has been widely studied to assess the safety of aerosols in many fields. The study herein investigates the degradation products formed from MONQ personal aromatherapy devices- a new non-nicotine aromatherapy vape pen device on the market. These pens are marketed to alleviate symptoms of an unrecognized medical syndrome called “terpene deficiency”. These pens contain a glycerin (GL), or glycerol (VG), base and a blend of terpene-rich essential oils. Previous studies have investigated the degradation of both VG and terpenes and have shown that concerning compounds are released in the gas phase, including benzene, benzaldehyde, methacrolein and methyl vinyl …

Design And Synthesis Of Novel No-Drug Hybrid Compound And Green Catalytic Activity Evaluation Of Synthesized Silver Nanoparticles-Halloysite Nanocomposite, Majed Abdullah Bajaber

LSU New Orleans Theses and Dissertations

Acetaminophen is a well-known analgesic that can manage pain and reduce fever. SCP-1 is a derivative of acetaminophen that showed significantly reduced hepatotoxicity and nephrotoxicity comparative to acetaminophen. Nitric oxides have been well known to play a key role in a wide variety of physiological and pathophysiological important processes. It was therefore of interest to synthesize a nitric oxide donor linked to SCP-1 that could have enhanced analgesic and antipyretic activity. A furoxan CAS 1609 as NO-donor was synthesized and linked to SCP-1 successfully. The furoxan CAS 1609 was initially synthesized from tetronic acid to give 1,2- dioxime in 86 …

Alkylation Of Benzene On Immobilized Phosphotungstic Acid, Kofi Kankam

Electronic Theses and Dissertations

Linear alkylbenzenes (LAB) are key intermediates in the synthesis of linear alkylbenzene sulfonate surfactants that are used in the manufacture of detergents. Production of LAB with traditional Lewis acids as catalysts, such as hydrofluoric acid, results in the formation of large amounts of toxic wastes and corrosion of industrial equipment. Phosphotungstic acid (PTA) has gained much attention in recent years as a solid catalyst for various alkylation reactions. This research work aims to develop a novel material based on PTA-containing silica gel, which can effectively catalyze LAB synthesis. Sol-gel synthesis of silica gel in the presence of PTA and tetraethyl …

Aryne-Guided C-H Functionalization Of Benzenoid Rings Using Diaryliodonium Salts, Aleksandra Nilova

Dissertations and Theses

The benzenoid core is a frequent and irreplaceable component of biologically active molecules. Structure function relationship of these compounds has been broadly analyzed and presented in numerous literature reports. Herein, we augmented existing knowledge by a broad analysis of the benzenoid substitution patterns in small molecule active pharmaceutical ingredients approved by the FDA. Our findings reveal a strong correlation that the most represented substitution patterns are those achieved via S_EAr. Despite the rapid development of methods to functionalize benzenoid rings, the lack of synthetic methodologies to access sterically and electronically unfavorable positions is highlighted. We sought to establish …

Profile Of Volatile Organic Compounds (Vocs) From Cold-Processed And Heat-Treated Virgin Coconut Oil (Vco) Samples, Ian Ken D. Dimzon, Grace B. Tantengco, Noel A. Oquendo, Fabian M. Dayrit

Chemistry Faculty Publications

Virgin coconut oil (VCO) can be prepared with or without heat. Fermentation and centrifuge processes can be done without the use of heat (cold process), while expelling involves heat due to friction. Volatile organic compounds (VOCs) from VCO samples prepared using these three methods were collected using solid phase microextraction (SPME) and analyzed using gas chromatography–mass spectrometry (GC-MS). Twenty-seven VCO samples from nine VCO producers were analyzed. The VOCs from refined, bleached, and deodorized coconut oil (RBDCO) were also obtained for comparison. Fourteen compounds were found to be common in more than 80% of the VCO samples analyzed. These included: …

Methods For 1,2-Cis-Selective O-Glycosylation And Synthesis Of An A. Baumannii Lipooligosaccharide Core Disaccharide, Ashley Fulton

LSU Doctoral Dissertations

This dissertation focuses on the formation of organic thin films on gold surfaces and synthesis of oligosaccharides. Chapter one, is a brief introduction on the utility of thin films, as well as ways to characterize thin films, as well as, a report on the attempt to form organic thin films on Au(111) surfaces using photoredox catalysis.

Glycoconjugates on cell surfaces serve as important mediators of intercellular recognition, adhesion, and viral infection. Due to the significant role that glycoconjugates play on the surface of cells, oligosaccharide synthesis is of great interest. Chapter two, is an extensive review of oligosaccharide synthesis, its …

A New Lc-Ms/Ms Technique For Separation Of Gangliosides Using A Phenyl-Hexyl Column: Systematic Separation According To Sialic Acid Class And Ceramide Subclass, Ashta Lakshmi Prasad Gobburi, Eric Wekesa Kipruto, Denise M. Inman, David J. Anderson

Chemistry Faculty Publications

A LC-MS/MS technique separated the bovine and mouse brain gangliosides monosialotetrahexosylgangliosides (GM1), disialotetrahexosylgangliosides (GD1a), trisialotetrahexosylgangliosides (GT1b) and tetrasialotetrahexosylgangliosides (GQ1b) using a phenyl-hexyl HPLC column and employing a linear methanol gradient in water, which is 0.028% in ammonium hydroxide. The gangliosides were separated according to sialic acid class, and within a particular class, gangliosides having different ceramide carbon chain lengths were also separated. All gangliosides of a particular sialic acid class eluted in characteristic retention time windows in the order of GQ1b, (earliest), GT1b, GD1a, and GM1 (latest). Within each specific retention time window for a particular ganglioside class, gangliosides were …

Design, Synthesis Of Axial Chiral Triazole, Jing Wang

USF Tampa Graduate Theses and Dissertations

This thesis contains three parts: 1) The briefly review of chiral P, N-ligands. 2) The summary of triazole as ligands. 3) The attempt of designing, synthesizing the chiral triazole ligands.

In the first part, we have reviewed all the major P, N-ligands in the history, including how they were synthesized and resolved into single enantiomer. We also used some examples to show their utility potential in different reactions.

In the second part, we summarized the triazole ligands which mainly developed by our group including their structures, their potential and utility in different types of chemical reactions.

In the last part, …

Chemical Synthesis Of Homogeneous Human E-Cadherin N-Linked Glycopeptides: Stereoselective Convergent Glycosylation And Chemoselective Solid-Phase Aspartylation, Chen Zeng, Bin Sun, Xuefeng Cao, Joshua Zhu, Olawale Micheal Oluwadahunsi, Ding Liu, He Zhu, Jiabin Zhang, Qing Zhang, Gaolan Zhang, Christopher Andrew Gibbons, Yunpeng Liu, Jun Zhou, Peng George Wang

Faculty Work Comprehensive List

We report herein an efficient chemical synthesis of homogeneous human E-cadherin N-linked glycopeptides consisting of a heptapeptide sequence adjacent to the Asn-633 N-glycosylation site with representative N-glycan structures, including a conserved trisaccharide, a core-fucosylated tetrasaccharide, and a complex-type biantennary octasaccharide. The key steps are a chemoselective on-resin aspartylation using a pseudoproline-containing peptide and stereoselective glycosylation using glycosyl fluororide as a donor. This synthetic strategy demonstrates potential utility in accessing a wide range of homogeneous N-linked glycopeptides for the examination of their biological function.

Modular Synthesis And Transition Metal-Free Alkynylation/Alkenylation Of Castagnoli–Cushmanderived N,O- And N,S-Heterocyclic Vinyl Chlorides, Timothy K. Beng, Abdikani Omar Farah, Victoria Shearer

All Faculty Scholarship for the College of the Sciences

A modular and functional group-tolerant protocol for the transition metal-free coupling of novel N,O- and N,S-heterocyclic vinyl chlorides with terminal acetylenes and styrenes has been developed, leading to the epimerization-free synthesis of fully carbofunctionalized dihydro-1,4-oxazines/thiazines. Bicyclic morpholines have also been prepared through the interrogation of newly synthesized cross-conjugated dienes in Diels–Alder reactions. The use of environmentally benign reaction media endows the current strategy with a practical advantage.

Covalent Organic Frameworks As An Organic Scaffold For Heterogeneous Catalysis Including C-H Activation, Harsh Vardhan

USF Tampa Graduate Theses and Dissertations

Linking small organic molecules into an extended solid usually afford disordered amorphous polymers. The instigation of order into such a material is of profound interest to induce inherent fine control of the overall structure. Covalent organic frameworks (COFs) are new class of porous crystalline material prepared by connecting organic building blocks via strong covalent bonds. The judicious choice of organic monomers can give rise to highly ordered and predictable frameworks with high crystallinity, surface area, and thermal/chemical stability. The role of connecting linkages such as B─O, C─C, C─N extends the principle of fundamental molecular covalent chemistry to the formation of …

Synthesis Of Novel Thiazole And Pyrazole Derivatives As Antimicrobial And Anticancer Agents, Md Mahbub Kabir Khan

Student Theses and Dissertations

This thesis contains two chapters. In chapter one, I report the synthesis of new pyrazole derivatives from dicarboxylic acid containing phenyl-derived, monotrifluoromethyl phenyl-derived, and acetovanillone-derived pyrazole aldehydes using Hantzsch ester. All of our pyrazole compounds have been synthesized efficiently using Hantzsch ester without any catalyst. Most of our pyrazole and thiazole compounds have been effectively recrystallized with acetonitrile and methanol respectively. We have synthesized 99 different pyrazole, 17 fused-thiazole ethisterone, and D-(-) norgestrel derivatives in good yield. In the present research, it has been shown possible to synthesize novel pyrazoles and thiazoles by using readily available starting materials and benign …

Ruggedized Color Measurement For Beer, Wort, And Malt, Roger Barth, Randall H. Reiger, Yuki Kim

Chemistry Faculty Publications

The standard instrument for measuring malt, wort, and beer color is the spectrophotometer. Spectrophotometers are not rugged; they have critically aligned collimators, monochromators, lenses, slits, and mirrors that make them difficult to use and maintain in a production environment. Our research shows that wort and beer color can be measured accurately with rugged equipment based on light emitting diodes (LEDs) with results in agreement with those of a spectrophotometer. Two or more colored diodes were used. LED-based apparatus does not require critical alignment, is not highly sensitive to environmental conditions such as temperature, moisture, dust, and vibration, and can be …

Nanoscale Battery Cathode Materials Induce Dna Damage In Bacteria, Tian A. Qiu, Valeria Guidolin, Khoi Nguyen L. Hoang, Thomas Pho, Andrea Carra, Peter W. Villalta, Jiayi He, Xiaoxiao Yao, Robert J. Hamers, Silvia Balbo, Z Vivian Feng, Christy L. Haynes

Faculty Authored Articles

The increasing use of nanoscale lithium nickel manganese cobalt oxide (LixNiyMnzCo1−y−zO2, NMC) as a cathode material in lithium-ion batteries poses risk to the environment. Learning toxicity mechanisms on molecular levels is critical to promote proactive risk assessment of these complex nanomaterials and inform their sustainable development. We focused on DNA damage as a toxicity mechanism and profiled in depth chemical and biological changes linked to DNA damage in two environmentally relevant bacteria upon nano-NMC exposure. DNA damage occurred in both bacteria, characterized by double-strand breakage and increased levels of many putative chemical modifications on bacterial DNA bases related to direct …

Nucleic Acid Delivery With Α-Tocopherol-Polyethyleneimine-Polyethylene Glycol Nanocarrier System., A K M Nawshad Hossian, Seetharama D Jois, Subash C. Jonnalagadda, George Mattheolabakis

College of Science & Mathematics Departmental Research

Purpose: Nucleic acid-based therapies are a promising therapeutic tool. The major obstacle in their clinical translation is their efficient delivery to the desired tissue. We developed a novel nanosized delivery system composed of conjugates of α-tocopherol, polyethyleneimine, and polyethylene glycol (TPP) to deliver nucleic acids.

Methods: We synthesized a panel of TPP molecules using different molecular weights of PEG and PEI and analyzed with various analytical approaches. The optimized version of TPP (TPP

Results: Through a panel of synthesized molecules, TPP

Conclusion: These results indicate that we successfully synthesized the TPP

Synthesis Of New Pyrazole & Thiazole Derivatives As Antimicrobial And Anticancer Agents, Ibrahim Saleh Alkhaibari

Student Theses and Dissertations

This thesis contains two chapters. In chapter one, we are reporting an efficient synthesis of eighty new pyrazole derivatives: sixty 4-trifluoromethyl and 3,5 bis(trifluoromethyl)phenyl substituted pyrazole-derived anilines, and twenty 4-trifluoromethyl-phenyl substituted pyrazole-derived hydrazones. Some of the pyrazole derivatives have been tested against several bacterial strains and have shown promising results. In Chapter two, we are reporting a synthesis of novel fused-thiazole- nootkatone derivatives. These compounds have been tested as well against a broad spectrum of Gram-positive and Gram-negative bacteria. However, they have just shown activity against some of the Gram-positive bacteria. Further anti-cancer and toxicity studies of these compounds are …

Synthesis Of Biologically Active Phosphorus Heterocycles, Giri Gnawali

Dissertations

This dissertation work is divided into two parts. The first part is focused in the development of methodology for the synthesis of phostones and phosphonosugars and advancement thereof. The second part is focused in the development of affinity probes based on analogs of natural products cyclophostin and the cyclipostins.

Phostone (3) and phosphonosugars are cyclic phosphonates. The anomeric carbon of sugar is replaced by a phosphorus atom. The synthesis of phostones has been achieved starting form the key intermediate, γ,δ-epoxy vinyl phosphonate (1). The palladium catalyzed ring opening of γ,δ-epoxy vinyl phosphonates by a nucleophile results …

Small Molecule Synthetic Carbohydrate Receptors, Marcelo F. Bravo Carranco

Dissertations, Theses, and Capstone Projects

Carbohydrate – receptor interactions are often involved in the attachment of viruses to host cells, and this docking is a necessary step in the virus life cycle that precedes infection and, ultimately, replication. Despite the conserved structures of the glycans involved in docking, they are still considered “undruggable”, meaning these glycans are beyond the scope of conventional pharmacological strategies. Recent advances in the development of synthetic carbohydrate receptors (SCRs) – small molecules that bind carbohydrates – could bring carbohydrate-receptor interactions within the purview of druggable targets. Here we discuss the role of carbohydrate-receptor interactions in viral infection, the evolution of …

Asymmetric Alpha-Stannylation Of Heterocycles And Their Subsequent Use In Cross-Coupling Reactions, Haoran Zhao

Dissertations, Theses, and Capstone Projects

α-Substituted oxygen-containing heterocycles are commonly present in biologically active molecules. Statistics shows that at least one α-substituted ether moiety appears in over 20% of the top 200 small-molecule pharmaceuticals. This project illustrates a reliable regioselective method to introduce simple cyclic ethers towards the diversification of small molecules. Aryl halides bearing various functional groups were well tolerated independent of their electronic properties. It was found that cyclohexyl spectator ligands on tin selectively slows transmetallation of undesired units, circumventing the competitive transfer of n-butyl group from ⁿBu₃SnR reagents. Compared to the normally used ⁿBu₃SnR reagents, Cy …

I. Selective Chlorination And Fluorination Of Quinols Ii. Synthetic Study Of Strongylophorine-26, Sihan Li

Dissertations, Theses, and Capstone Projects

Organic compounds containing halogen are an important and useful class of intermediates that can be converted to other functionalities. This thesis describes our strategy in selective chlorination and fluorination of quinols to offer the corresponding aromatic structures. Quinols, or cyclohexadienones, as oxidized derivatives of phenols, have their remarkable chemical reactivities, including additions to enone, enolate alkylations, aldol reactions, cycloadditions, and rearrangements. Dienone-phenol rearrangement provides the asymmetric route since the stereocenters located in the six-membered ring of various cyclohexadienone were widely using in building larger chiral arrays for many total syntheses

Chapter one of this thesis discusses our new selective nucleophilic …

Pressure Driven Desalination Utilizing Nanomaterials, Fangyou Xie

Master's Theses

Nanomaterials such as graphene oxide and carbon nanotubes, have demonstrated excellent properties for membrane desalination, including decrease of maintenance, increase of flux rate, simple solution casting, and impressive chemical inertness. Here, two projects are studied to investigate nanocarbon based membrane desalination. The first project is to prepare hybrid membranes with amyloid fibrils intercalated with graphene oxide sheets. The addition of protein amyloid fibrils expands the interlayer spacing between graphene oxide nanosheets and introduces additional functional groups in the diffusion pathways, resulting in increase of flux rate and rejection rate for the organic dyes. Amyloid fibrils also provide structural assistance to …

Isolation, Structure Elucidation, And Synthesis Of Natural Products From Marine Cyanobacteria, Keren Solomon

Electronic Theses and Dissertations

This thesis describes the isolation, structure elucidation, and synthesis of natural products from marine cyanobacteria. A crude extract from a cyanobacterium collected in Curacao showed selective affinity for the dopamine D₅ receptor in a screen against a panel of CNS receptors. Due to the high similarity of the D₅ and D₁ receptor, to date there are no known ligands that differentiate them. Attempts to purify the compound responsible for this affinity led to the isolation of the known compound caylobolide A. A second extract from a cyanobacterium collected in Panama underwent bioassay-guided fractionation and yielded the novel …

Synthesis Of Alpha-Methylselenocysteine, Its Relevant Analogues, And An Unnatural Glutathione Disulfide Core, Robert J. Wehrle

Dissertations

Selenoproteins, such as glutathione peroxidase, have gained interest for their ability to act as antioxidants, and their potential to act as anti-cancer agents. Synthesizing and studying selenoproteins can be problematic, however, due to their propensity to degrade from over-oxidation. The degradation from over-oxidation can be avoided by the incorporation of the unnatural amino acid, alpha-methylselenocysteine. A synthesis utilizing methyl malonic esters was used to synthesize protected (R)-alpha-methylselenocysteine efficiently (46% over four steps) and in high enantio-purity (88% enantiomeric excess). Using similar procedures, the (S)-enantiomer was also synthesized as well as a beta-analogue.

The use of enzymes …

Innovative Approaches In The Discovery Of Aquatic Mycobacteriophages, Janis H. Doss

Biomedical Sciences Theses & Dissertations

Bacteriophages (phages), viruses that infect bacteria, have many applications in medicine, agriculture, molecular biology, and other fields. As antibiotic resistance becomes an increasing problem, interest in phages has grown. The traditional techniques of phage discovery are successful for some phages, but others require modified procedures to achieve detectable host infection.

Mycobacterium is a diverse bacterial genus characterized by a unique cell wall containing mycolic acids, which aids in survival and pathogenesis. The aims of the present research were to isolate mycobacteriophages, use bioinformatics techniques to analyze mycobacterial prophages, and combine genetic analysis with multi-well plate host range studies to identify …

(Pseudo)Phase Tuning In The Service Of Synthesis: Technologies For Sustainable Catalysis., Justin Douglas Smith

Electronic Theses and Dissertations

Strategies for manipulation of chemical phases were explored with emphasis on synthetic chemistry applications. Some strategies are fairly divergent from their origin, but all ultimately began from investigations of micellar media. Accordingly, Chapter 1 reviews the historical development of micellar catalytic processes. Chapters 2 and 3 detail development of synthetic methods in micellar solutions of designer surfactant PS-750-M. PS-750-M was designed to create benign micellar solutions which effectively mimic toxic organic solvents; it contains a proline-based linker between its hydrophobic and hydrophilic regions which imparts increased polarity to the micellar core. Chapter 2 details an interfacial nucleophilic substitution of perfluoroarenes …

In Silico Investigation For The Conversion Of Methyl Oleate To Gasoline, Arkanil Roy

Graduate Theses/Dissertations

Petroleum products are found in all walks of life. From the plastic casing on a cell phone to the gasoline that runs most vehicles, a lot is derived from petroleum. Ubiquitous use of petroleum has adversely affected the environment. Toxic substances such as SOx and NOx are released into the atmosphere during the processing and usage of petroleum products, which contributes to global warming. Inevitable oil spills cause devastating effects to marine ecosystems. The rate of regeneration of petroleum is much slower than the rate of usage that would lead to it being exhausted in the recent future. Hence, a …

Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, Croix J. Laconsay, Henry B. Wedler, Dean J. Tantillo

Journal of Science Education for Students with Disabilities

This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.

The Development Of A New Entry Point Into Enantiomerically Enriched Sulfinyl Derivatives, Jessica Shaw

Theses and Dissertations

Optical probes may be used as reliable tools for detecting and imagining the inside of cells for medical diagnostics. Among available options, the use of thiol probes is of interest as thiols are present in nearly all cells and their levels are tightly regulated, thus any variation is associated with disease. A proper thiol bioimaging probe must have a thiol cleavage group/reactive group and a fluorophore. It is found that novel sulfinate aryl ester (phenoxysulfinate esters) probes selectively cleave thiols at physiological pH and show much promise as effective tools for bioimaging.

In this context, the synthesis of the related …

Global Atmospheric Budget Of Acetone: Air-Sea Exchange And The Contribution To Hydroxyl Radicals, Siyuan Wang, Eric C. Apel, Rebecca H. Schwantes, Kelvin H. Bates, Daniel J. Jacob, Emily V. Fischer, Rebecca S. Hornbrook, Alan J. Hills, Louisa K. Emmons, Laura L. Pan, Shawn Honomichl, Simone Tilmes, Jean‐François Lamarque, Mingxi Yang, Christa A. Marandino, E. S. Saltzman, Warren J. De Bruyn, Sohiko Kameyama, Hiroshi Tanimoto, Yuko Omori, Samuel R. Hall, Kirk Ullmann, Thomas B. Ryerson, Chelsea R. Thompson, Jeff Peischl, Bruce C. Daube, Róisín Commane, Kathryn Mckain, Colm Sweeney, Alexander B. Thames, David O. Miller, William H. Brune, Glenn S. Diskin, Joshua P. Digangi, Steven C. Wofsy

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Acetone is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere. The oceans impose a strong control on atmospheric acetone, yet the oceanic fluxes of acetone remain poorly constrained. In this work, the global budget of acetone is evaluated using two global models: CAM‐chem and GEOS‐Chem. CAM‐chem uses an online air‐sea exchange framework to calculate the bidirectional oceanic acetone fluxes, which is coupled to a data‐oriented machine‐learning approach. The machine‐learning algorithm is trained using a global suite of seawater acetone measurements. GEOS‐Chem uses a fixed surface seawater concentration of acetone to calculate the oceanic fluxes. Both …