Organic Chemistry Commons^™

Access To Nitrogen Heterocycles Via Borrowing Hydrogen Catalysis, Robert P. Reynolds, Kellen P. Mcguire, Conor T. Mccormick, Kyle M. Lambert

Undergraduate Research Symposium

Nitrogen heterocycles are ubiquitous motifs which occur as the core structure of several alkaloid natural products exhibiting inherent biological activity against an array of bacteria, fungi, viruses, and cancer cell lines. These azacycles serve as key synthetic building blocks for medicinal chemists to access more structurally complex and diverse compounds with tunable biological properties. A synthetic approach to these valuable motifs employing intramolecular borrowing hydrogen catalysis has been developed. The utility of the developed chemistry will be applied to synthetic efforts towards the recently isolated Cylicomorphins A-E.

Oxidation Of Thiols To Disulfides Using An Environmentally “Green” Organocatalyst And New Mechanistic Insights, Kosta V. Vlasakakis, Olivia M. White, Robert P. Reynolds, Shayne M. Weierbach, Shannon M. Weaver, Ramsey T. Ritter, Nishi H. Patel, Eric C. Hayes, Sydney Dunmire, Kyle M. Lambert

Undergraduate Research Symposium

The selective oxidation of thiols to disulfides is an area of great importance in the areas of materials and medicinal chemistry research. The production of polymers, rubber, pharmaceuticals, and the folding of proteins in biological systems all rely on the formation of disulfide bonds. Herein, we introduce a stoichiometric and electrocatalytic method for the oxidation of various pharmaceutically and biologically relevant thiols into their respective disulfides in more environmentally benign solvents such as water and alcohol solvents. The scope of the transformation was evaluated and a detailed mechanistic study involving control experiments, experimental kinetic studies, and computational investigations led to …

Developing Efficient Transition Metal Catalyzed C-C & C-X Bond Construction, Chiyu Wei

USF Tampa Graduate Theses and Dissertations

This dissertation mainly contains three parts: 1) The synergistic Pd/enamine catalysis for asymmetric hydrocarbon functionalization of unactivated alkenes with ketones; 2) Gold redox catalysis with a selenium cation as mild oxidant; 3) HFIP promoted disulfidation and diselenation of alkyne, alkene, and allene.

Palladium-catalyzed alkene activation has its intrinsic limitation: 1) the requirement of a pre-functionalized alkene to form a Pd π-allyl complex; 2) problematic reversible β-H elimination. It always leads to limited reaction scope and losing of the stereochemical control. Synergistic palladium and enamine catalysis was conducted to promote ketone addition to unactivated olefins. A secondary amine-based organocatalyst was identified …

Growth Kinetics Determine The Polydispersity And Size Of Pbs And Pbse Nanocrystals, Michael P. Campos, Jonathan De Roo, Matthew W. Greenberg, Brandon M. Mcmurtry, Mark P. Hendricks, Ellie Bennett, Natalie Saenz, Matthew Y. Sfeir, Benjamin Abecassis, Sanjit K. Ghose, Jonathan S. Owen

Advanced Science Research Center

A library of thio- and selenourea derivatives is used to adjust the kinetics of PbE (E = S, Se) nanocrystal formation across a 1000-fold range (kr = 10−1 to 10−4 s−1), at several temperatures (80–120 °C), under a standard set of conditions (Pb : E = 1.2 : 1, [Pb(oleate)2] = 10.8 mM, [chalcogenourea] = 9.0 mM). An induction delay (tind) is observed prior to the onset of nanocrystal absorption during which PbE solute is observed using in situ X-ray total scattering. Density functional theory models fit to the X-ray pair distribution function (PDF) support a Pb2(μ2-S)2(Pb(O2CR)2)2 structure. Absorption spectra …

4,6-O-Phenylethylidene Acetal Protected D-Glucosamine Carbamate-Based Gelators And Their Applications For Multi-Component Gels, Pooja Sharma, Guijun Wang

Chemistry & Biochemistry Faculty Publications

The self-assembly of carbohydrate-based low molecular weight gelators has led to useful advanced soft materials. The interactions of the gelators with various cations and anions are important in creating novel molecular architectures and expanding the scope of the small molecular gelators. In this study, a series of thirteen new C-2 carbamates of the 4,6-O-phenylethylidene acetalprotected D-glucosamine derivatives has been synthesized and characterized. These compounds are rationally designed from a common sugar template. All carbamates synthesized were found to be efficient gelators and three compounds are also hydrogelators. The resulting gels were characterized using optical microscopy, atomic force microscopy, …

Synthesis Of Phosphonate-Based Diimide Ligands, Kenya V. Medina

Honors Program Theses and Research Projects

There has been a resurged interest in the synthesis of metal-organic frameworks because of their potential applications in energy production and drug delivery. Although diimides are insoluble in aqueous solutions, the addition of phosphonic acid allows the complex to be water soluble, which greatly increases their application. Therefore, the creation of a hybrid metal-organic complex by the addition of phosphonic groups to diimide ligands can result in a polar porous compound. In this project the ligand design included the use of dianhydrides including pyromellitic dianhydride, naphthalenetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride, and biphenyl-tetracarboxylic acid dianhydride. These dianhydride precursors were refluxed under argon …

Speciation Of Diaryliodonium Salts In Solution And Their Reactivity Towards N-Nucleophiles (Phthalimide And Amines) And O-Nucleophiles (Phenols And Phenoxide), Souradeep Basu

Dissertations and Theses

Benzenoid rings are prevalent in pharmaceutical drug molecules, agrochemical molecules and even in some polymers used in electronic device. Aryl rings are often installed using metal catalysis, however, metal free arylations are known but limited. Diaryliodonium salts are novel electrophilic arylating agents. Herein, metal free N-arylation of phthalimide and diarylether formation using aryl(TMP)iodonium salts is described.

The structure of diaryliodonium salts has been primarily studied in either the solid state or in-silico. The structure and speciation of diaryliodonium salts in solution is not well explored. In this work evidence of dimer formation of aryl(Mes)iodonium salts in chloroform using …

Methanol Decomposition On Ni(111) And O/Ni(111), Henrik Öström, Bingjie Zhang, Tiffany Vallejo, Bryn Merrill, Jeremy Huang, Jerry Larue

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Methanol decomposition on Ni(111) surfaces has been studied in the presence and absence of oxygen using temperature-programmed desorption and temperature-dependent sum frequency generation spectroscopy. Under both conditions the C–H and O–H bonds break, forming carbon monoxide and atomic hydrogen on the surface. No C–O bond scission was observed, limiting the number of reaction pathways. The O–H bonds break first (>150 K), forming surface methoxy, followed by C–H bond breakage (>250 K). All atomic hydrogen desorbs from the surface as H2 through H+H recombinative desorption. H2 desorbs at a higher temperature in the presence of oxygen (>300 K) …

One-Pot Conversion Of Carboxylic Acids To Aldehydes, Hannah Khan, Michael Nantz, Saurin Sutaria

Posters-at-the-Capitol

There are many different ways to convert a carboxylic text acid to an aldehyde. A common way to accomplish this transformation is to use multiple steps (e.g., reduction of the carboxylic acid to the corresponding alcohol followed by selective oxidation to the aldehyde). Our success in reducing the diacid muconic acid (1) to muconaldehyde (4) in a relatively mild, one-pot process has led us to examine whether the method can be expanded to other carboxylic acids. We report here our findings using benzoic acid as a representative substrate.

Lipophilic Probes For Cellular Ethylene Detection, Morgan R. Brown

Electronic Theses and Dissertations

The structure of ethylene is simple, yet its biological effects are significant. When considering its role in biology it is almost exclusively regarded as a plant hormone. Research on ethylene from plants was progressed by several advancements in analytical instrumentation, from its discovery to elucidation of its signaling pathway. There is currently limited understanding of ethylene’s role in mammals, but evidence suggests that it may be a biomarker for oxidative stress! Additional tools and technology are crucial to study this surprising and important signaling role in mammals. Our group has developed molecular ethylene probes as a strategy to detect ethylene …

Esipt-Enabled Alkyne Migration Provides Rapid Access To Benzoxazinones, Andrés G. Muñoz

Electronic Theses and Dissertations

Benozoxazinones have long been of interest to agrochemical scientists and medicinal chemists because of their widespread biological activity. These scaffolds are also of interest to synthetic chemists, who recognize the utility of benzoxazinones for accessing functionalized heterocycles. The use of efavirenz, a benzoxazinone-based reverse transcriptase inhibitor used in the treatment of HIV-1, has brought increased attention to this privileged pharmacophore. While there exist numerous strategies for synthesizing benzoxazinones, methods that do not require the use of acutely toxic and environmentally hazardous reagents are lacking. Consequently, there is a need to develop new methods for constructing this valuable scaffold. Herein, we …

Modelling Quinones Using Density Functional Theory, David Ruiter, Madeleine Callan, Elijah Gruszecki, Maya Nambisan, Dr. K. V. Lakshmi

Summer Research

We modelled benzoquinone (BQ), dichlorobenzoquinone (DCBQ), and dimethylbenzoquinone (DMBQ) using the ORCA quantum chemistry computation suite. We obtained singlepoint energies, electron and spin densities, and the hyperfine coupling values for each molecule suspended in dimethyl sulfoxide (DMSO) and isopropyl alcohol (IPA). In most cases, we find close agreement with published literature values.

An Approach To The Synthesis Of 3-Quinazolinedione Carboxylic Acids: Putative Antibiotics, Colton J. Stonehouse, Michael Barbachyn

Summer Research

Bacterial resistance to antibiotics is a growing public health threat. Each year, more than 2.8 million antibioticresistant infections occur in the United States and 35,000 people die as a consequence. Fluoroquinolone (FQ) agents targeting the essential bacterial type II topoisomerases DNA gyrase and topoisomerase IV, exemplified by ciprofloxacin, have been in clinical use since the 1980’s and shown to be useful antibiotics. Unfortunately, heavy use of the FQs has inevitably led to the development of FQ-resistant pathogens

Development Of New Photochemical Tools For Applications In Cancer Research And Enzymatic Signaling, Nicholas Paul Toupin

Wayne State University Dissertations

Photochemical tools empower researchers to act with precision and control over the cellular environment through production of reactive oxygen species (ROS), targeted drug delivery, and modulation of enzymatic activity. These molecular tools use light as a readily available, biorthogonal reagent for initiating advantageous light-activated reactions. Using light in this way allows researchers to affect the cellular environment in specific ways with high spatio-temporal control. This dissertation focuses on expanding the applications of, mostly Ru(II)-based, photoactivated chemicals. Complexes of this type are able to act as photosensitizers in photodynamic therapy (PDT), as photocages (PCT), or as dual-action compounds capable of both …

Phenanthroline-Catalyzed 1,2-Cis Glycosylation: Scope And Mechanism, Jiayi Li

Wayne State University Dissertations

Phenanthroline, a rigid and planar organic compound with two fused pyridine rings, has been used as a powerful ligand for metals and a binding agent for DNA/RNA. We recently discovered that phenanthroline could be used as a nucleophilic catalyst to access high yielding and diastereoselective α-1,2-cis glycosides through the coupling of hydroxyl acceptors with α-glycosyl bromide donors. The utility of the phenanthroline catalysis is expanded to sterically hindered hydroxyl nucleophiles and chemoselective coupling of an alkyl hydroxyl group in the presence of a free C1-hemiacetal functionality. In addition, the phenanthroline-based catalyst has a pronounced effect on site-selective couplings of triol …

Whole Exome Sequencing Identifies A Novel Mutation In Aspm And Ultra-Rare Mutation In Cdk5rap2 Causing Primary Microcephaly In Consanguineous Pakistani Families, Ehtisham Ul Haq Makhdoom, Haseeb Anwar, Shahid Mahmood Baig, Ghulam Hussain

Department of Biological & Biomedical Sciences

Background & objectives: Primary Microcephaly (MCPH) is a rare neurogenetic disease, manifesting congenitally reduced head circumference and non-progressive intellectual disability (ID). To date, twenty-eight genes with biallelic mutations have been reported for this disorder. The study aimed for molecular genetic characterization of Pakistani families segregating MCPH.
Methods: We studied two unrelated consanguineous families (family A and B) presenting >2 patients with diagnostic symptoms of MCPH, born to asymptomatic parents. We employed whole-exome sequencing (WES) of probands to find putative causal mutations. The candidate variants were further confirmed and analyzed for co-segregation by Sanger sequencing of all available members of each …

Synthesis And Characterization Of Chitosan Derivatives Intended For Gene Delivery Applications, Alex M. Mcmullen

Graduate Theses/Dissertations

Chitosan has been studied as a non-viral vector capable of efficient gene delivery due to its favorable properties such as biodegradability, biocompatibility, and is non-toxic to mammalian cells. Incorporating electrostatic interactions in non-viral vectors enhance the vector permeability. This work focuses on two parts. Firstly, cationic chitosan derivatives were synthesized using quarternary ammonium and phosphonium groups. This was achieved by coupling carboxylic acid ligands with these quarternary groups to chitosan through an amide bond. The carboxylic acid ligands were synthesized from 4-methylbenzoic acid and either triethyl phosphine or triethyl amine. The ligand was then attached to chitosan through an amide …

Microbial Labilization And Diversification Of Pyrogenic Dissolved Organic Matter, Aleksandar I. Goranov, Andrew S. Wozniak, Kyle W. Bostick, Andrew R. Zimmerman, Siddhartha Mitra, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the increased occurrence of wildfires around the world, interest in the chemistry of pyrogenic organic matter (pyOM) and its fate in the environment has increased. Upon leaching from soils by rain events, significant amounts of dissolved pyOM (pyDOM) enter the aquatic environment and interact with microbial communities that are essential for cycling organic matter within the different biogeochemical cycles. To evaluate the biodegradability of pyDOM, aqueous extracts of laboratory-produced biochars were incubated with soil microbes, and the molecular changes to the composition of pyDOM were probed using ultrahigh-resolution mass spectrometry (Fourier transform–ion cyclotron resonance–mass spectrometry). Given that solar irradiation …

Marcadores Moleculares Subrogados A La Repelencia Al Agua En Suelos Afectados Por El Fuego, Nicasio T. Jiménez-Morillo, Gonzalo Almendros, Nuno Guiomar, Ana Z. Miller, Cristina Barrocas-Dias, José M. De La Rosa, Patrick G. Hatcher, José A. González-Pérez

Chemistry & Biochemistry Faculty Publications

Soil water repellency (SWR) is often attributed to the accumulation of hydrophobic organic compounds, mainly lipids. Nonetheless, lipid extraction not always suppress SWR and unextractable soil constituents may be related with residual SWR. Burnt (B) and unburnt (UB) soils (Doñana National Park, Huelva) under two vegetations (cork oak and heather) and two soil fractions, coarse (1–2 mm) and fine (

Pd-Based Photocatalysts For Heck C-C Cross-Coupling Reactions, Suha Ali Alshehri

Masters Theses

Heck C-C cross-coupling reaction has been widely employed in synthetic organic chemistry because of its high efficiency and simplicity, however the conventional Heck C-C cross-coupling reaction conditions involve the use of an expensive toxicant phosphine-ligated palladium complexes, and high temperature. To address these drawbacks, a highly efficient, homogeneous photocatalyst based on BODIPY for the Heck C-C cross-coupling reactions of aryl iodide and methyl acrylate in DMF solvent under inert conditions has been developed. The 4-Py-BDP-Pd, 3-Py-BDP-Pd and, 2-Py-BOD-Pd catalysts were synthesized and purified using column chromatography. The optical properties of products and intermediates were studied by UV/vis absorption and fluorescence …