Organic Chemistry Commons^™

Synthesis Of Bacterial Glycerophospholipids For Biomembrane Model Studies: A Means To Advanced Biofuels, Felix Adulley

Electronic Theses and Dissertations

To reduce reliance on fossil fuels, sustainable biofuels are being pursued, especially advanced biofuels like 1-butanol that have higher energy content and greater compatibility with existing infrastructure than ethanol. A persistent challenge is the yield-limiting toxicity of biofuels and process solvents, such as tetrahydrofuran, to the microbes that ferment biomass into biofuel. The cell membrane is a focal point of toxicity, and understanding how it interacts with fuels and solvents is key to improving yield. Phospholipid bilayers are the core of biomembranes, and model biomembranes of defined composition provide the ideal platform for biophysical studies. To this end, glycerophospholipids characteristic …

Quantifying The Role Of Water Quality On Nitrogen Cycling In A Trophic Estuary, Kayla Gonzalez-Boy

Symposium of Student Scholars

Jobos Bay Estuary is an intertidal, tropical estuary located in southern Puerto Rico. The estuary covers about 12 km² and has a variety of habitats, such as seagrass beds, mangroves, mud flats, and coral reefs, which play important roles in sediment trapping and water quality maintenance. Seagrasses also serve as nursery and feeding grounds and provide shelter for macrofauna. Currently, the role of seagrasses and water quality on nitrogen (N) cycling in trophic estuaries is not well constrained. Understanding variations in sediment-based effects on N cycling rates and transformations, and how they are associated with water quality, is an …

Reactive Chemistries For Protein Labeling, Degradation, And Stimuli Responsive Delivery, Myrat Kurbanov

Doctoral Dissertations

Reactive chemistries for protein chemical modification play an instrumental role in chemical biology, proteomics, and therapeutics. Depending on the application, the selectivity of these modifications can range from precise modification of an amino acid sequence by genetic manipulation of protein expression machinery to a stochastic modification of lysine residues on the protein surface. Ligand-Directed (LD) chemistry is one of the few methods for targeted modification of endogenous proteins without genetic engineering. However, current LD strategies are limited by stringent amino acid selectivity. To bridge this gap, this thesis focuses on the development of highly reactive LD Triggerable Michael Acceptors (LD-TMAcs) …

Contributions Of Tunneling In 8Π-6Π Electrocyclic Cascade Reactions Of Bicyclo[4.2.0]Octa-2,4-Diene Moieties, Ishika Jain, Claire Castro, William L. Karney

Featured Student Work

Six-electron electrocyclic reactions usually require relatively high temperatures; however recent research has shown that such reactions can occur at significantly lower temperatures in biosynthetic and biomimetic pathways. Pathways resulting in bicyclo[4.2.0]octa-2,4-diene moieties arise from thermally allowed 8π-6π electrocyclization cascade reactions of 1,3,5,7-octatetraenes, as in the biosynthesis of endiandric acids, elysiapyrones, and numerous other natural products. We report multidimensional tunneling calculations to explore the possible contribution of heavy-atom tunneling (e.g. by carbon) to biosynthetic pathways and biomimetic syntheses, and thus to provide a more complete picture of biochemical kinetics. M06-2X/cc-pVDZ calculations on the 8π-6π cascade cyclizations of methylated octatetraene model systems …

A Work Towards A Single-Bridge Hydrazine Sensor, Brenden Jay Schmeltz

Theses and Dissertations

Hydrazine can currently be detected by irreversible methods, Carbazolopyridinophane (2,18-Dithia[3][1,8]carbazolo[3][2,6]pyridinophane) CP was synthesized by Brown et al. to detect hydrazine in real-time while also being reversible. The threshold for detection was 100 ppb, regulatory use requires 10 ppb as this is when permanent damage to humans can be caused. A more sensitive sensor will allow for safer workplaces for many people. A single, 3-atom bridge sensor will further examine the photophysical capabilities of carbazole-pyridine as an emitter/quencher pair. 1-Carbazole-1-methylpyridyl-2methyl sulfide SBCP will allow freedom of rotation as well as the bending of the bridge. These benefits will introduce conformers which …

Scandium Triflate-Catalyzed Aromatic Aldehydic C-H Activation, Nicholas Griffin

Honors Projects

Herein described is a scandium triflate-catalyzed C-H activation of commercially available aromatic aldehydes achieved in low yields. The reaction occured in a one-pot synthesis over a two-hour duration and required minimal purification. Inclusion of a fluorine-tagged phenol allowed for reaction monitoring via ¹⁹FNMR.

Synthesis Of Biologically Active Tropolones And Stereochemically Rich Compounds Via Cross-Coupling Reactions, Nana B. Agyemang

Dissertations, Theses, and Capstone Projects

Over the past years the Murelli lab has established research based on the synthesis and biological evaluations of alpha-hydroxytropolones (alpha-HTs). These seven-membered aromatic rings have three contiguous oxygen atoms that chelates to metals, thus, biologically having the ability to bind dinuclear metalloenzymes and promoting inhibition. Synthetic routes to alpha-HT’s are scarce and therefore has been the main driving force in developing efficient and general synthetic methods to obtain variations in alpha-HTs, enabling SAR studies. The Murelli lab have therefore developed an oxidopyrylium cycloaddition/ring-opening strategy that is able to generate polysubstituted alpha-HTs starting from kojic acid, a cheap and readily available …

Stereospecific Cross-Coupling Reactions With Enantioenriched Electrophiles, Iv Kraja

Dissertations, Theses, and Capstone Projects

We have developed a novel palladium-catalyzed stereospecific C(sp³)–C(sp³) Stille cross-coupling reaction between carbastannatrane nucleophiles and α-(trifluoromethyl) benzylic tosylates. This constitutes the first example of a stereospecific C(sp³)–C(sp³) cross-coupling reaction using an enantioenriched electrophile and an alkyltin nucleophile. This system has the potential to be extended to cross-coupling reactions using configurationally stable enantioenriched nucleophiles, thus enabling stereochemical control of two newly formed contiguous stereocenters. Generating enantioenriched α-(trifluoromethyl) benzylic compounds also has importance in pharmaceutical and agrochemical industries.

Through the development of this reaction, our findings show that the addition …

Improved Stoichiometric Synthesis Of Ccc-Nhc Pincer Rh Complexes And Catalytic Activity Towards Dehydrogenative Silylation And Hydrosilylation Of Alkenes, Enock Amoateng

Theses and Dissertations

N-Heterocyclic carbenes (NHCs) have attracted growing interest not only as successful ancillary ligands in a wide variety of transition-metal-catalyzed reactions but have also shown to offer photophysical and electrochemical properties. The metalation/transmetalation strategy using [Zr(NMe₂)₄] as initial metalating reagent offers an efficient approach to the preparation of CCC-NHC pincer complexes of the late transition metals such as Rh and Ir. In the process of investigating an intermediate and the mechanism of the metalation/transmetalation to Rh sequence, a mixed valent bimetallic CCC-NHC pincer Rh complex with two chloro ligands bridged between a [(CCC-NHC)Rh(III)] and a [Rh(I)(COD)] fragment …

Composite And Polymer Formulation Employing Sulfur And Bio-Olefin Feedstocks, Claudia V. Lopez

All Dissertations

Environmental sustainability represents a challenge for society since industrial growth has a direct impact on natural resources and waste production. New technologies that effectively incorporate waste into renewable resources are critical to the development of a sustainable and circular economy. The manufacturing of structural materials like Portland cement (OPC) is responsible for >8% of the global anthropogenic emissions of carbon dioxide, with ~ 1 kg of CO₂ released to the atmosphere for every kilogram of OPC produced. For instance, the development of sustainable structural materials is a key factor to reduce the greenhouse emissions and to attenuate the climate …

New Methodologies For Sustainable Organic Synthesis In Water., Sudripet Sharma

Electronic Theses and Dissertations

Water is stable, benign, and green solvent. Its usage as a solvent in organic synthesis is significantly enhanced by micellar catalysis. However, replacing water as a reaction medium in organic synthesis is not sufficient to meet the sustainability challenges—excessive organic solvents are still required for product isolation and purification. Notably, solvents used in syntheses contribute to more than 80% of waste generation. In addition to solvents, the use of palladium in large amounts is also a problem for the future as it is a precious, low-abundance metal, and its supply is dwindling. Therefore, this dissertation highlights the various sustainable protocols …

Development And Applications Of Novel And Practical Fluorination Reagents., Yuhao Yang

Electronic Theses and Dissertations

The fluorine (F) atom has distinctive properties such as the highest electronegativity, small size, low polarizability, and strong C–F bond strength. Not surprisingly, fluorinated organic compounds have garnered significant attention in the pharmaceutical, agrochemical, and material fields. Since organofluorides are very rare in nature, we need fluorination reagents to help us transfer fluorine into the organic molecules. In past decades, a vast number of fluorination reagents have been developed and many of them are commercially available now. However, there is still much room for the improvement of these reagents. Our target is to develop novel and practical fluorination reagents to …

Synthesis And Reactivity Of Heteroatom Embedded Cycloalkynes In Spaac, Nickel Catalyzed Alkylarylation Of Alkenes, And Carbofluorination Of Alkynes, Namrata Khanal

Chemistry and Chemical Biology ETDs

Part I covers Chapters 1, 2, and 3

cycloaddition reactions, that is utilized in biorthogonal chemistry. This metal free version The strain promoted azide-alkyne cycloaddition (SPAAC) reaction is one of the popular 1,3-dipolar of click reaction offers advantage over copper catalyzed click reaction. Since it eliminates the use of copper that is toxic to cells, it is considered favorable for biocompatible reaction. Due to the increased reactivity with dipoles without the use of metal catalyst, cycloalkynes, in particular cyclooctynes, have been employed as the biorthogonal reagent in biorthogonal chemical reaction for the study of a biological processes in vivo. The …

Expansion Of The Diazacyclobutene Motif For Antiparasitic Evaluation, Brock Alexander Miller

All Dissertations

Molecules containing N-heterocycles are prevalent in pharmaceutical settings. The ability to generate highly functionalized molecules containing N-heterocycles in very few synthetic operations is valuable for drug discovery. Our group has developed a two-step synthesis to access a rarely studied diazacyclobutene scaffold via a formal [2+2] cycloaddition between 4-phenyl-1,2,4-triazolinedione and electron-rich thioalkynes. Our interest in this scaffold increased exponentially from promising preliminary biological evaluations against a protozoan parasite, Trypanosoma brucei. While we were able to double the number of historical examples of this scaffold, there were significant limitations in our methodology. The most notable limitations were the lack …

The Emergence Of Zerovalent Carbon Compounds From Structural Curiosities To Organocatalysts, Allegra L. Liberman-Martin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Low-valent main group compounds have reactivity patterns and properties reminiscent of transition metals. While divalent carbon compounds such as carbenes are widely studied ligands and organocatalysts, zerovalent carbon species have received considerably less attention. This perspective highlights the properties and reactivity of zerovalent carbon compounds, focusing on their first applications as organocatalysts for small molecule reduction and polymerization reactions.

Rhodium-Catalyzed Asymmetric Synthesis Of P-P And P-C Bonds, Sarah T. Chachula

Dartmouth College Ph.D Dissertations

Chapter 1: Synthesis, Structure, Dynamics, and Enantioface-Selective η3-Benzyl Coordination in the Chiral Rhodium Complexes Rh(diphos*)(η3-CH2Ph) Abstract: The rhodium benzyl complexes Rh(diphos*)(η3-CH2Ph) (1-14, diphos* = chiral bis(phosphine)) were prepared either by treatment of Rh(COD)(η3-CH2Ph) (15, COD = 1,5-cyclooctadiene) with diphos*, or from the reaction of [Rh(diphos*)(Cl)]2 (16- 20) with PhCH2MgCl. For C2-symmetric diphos*, observation of one set of NMR signals for complexes 1-12 suggested that the two diastereomers in which different 3-benzyl enantiofaces were coordinated to rhodium interconverted rapidly on the NMR time scale via suprafacial shifts; observation of five inequivalent aryl 1H NMR signals showed that antarafacial shifts were slow …

Scalable Preparation Of The Masked Acyl Cyanide Tbs-Mac, Haley Hinton, Jack Patterson, Jared Hume, Krunal Patel, Julie Pigza

Faculty Publications

This paper describes the three-step synthesis of TBS-MAC, a masked acyl cyanide (MAC) and a versatile one-carbon oxidation state three synthon. We have developed a scalable and detailed synthesis that involves: (1) acetylation of malononitrile to form the sodium enolate, (2) protonation of the enolate to form acetylmalononitrile, and (3) epoxidation of the enol, rearrangement to an unstable alcohol, and TBS-protection to form the title compound. Both the sodium enolate and acetylmalononitrile are bench-stable precursors to the intermediate hydroxymalononitrile, which can be converted to other MAC reagents beyond TBS by varying the protecting group (Ac, MOM, EE, etc.).

N–((2–Acetylphenyl)Carbamothioyl)Benzamide: Synthesis, Crystal Structure Analysis, And Theoretical Studies, Akin Oztaslar, Hakan Arslan

Karbala International Journal of Modern Science

N–((2–Acetylphenyl)carbamothioyl)benzamide has been synthesized and characterized. The molecular conformation of the investigated compound is stabilized by C16–H16B⋅⋅⋅O2ⁱ (i: 1+x, y, z) intermolecular and C14–H14⋅⋅⋅S1, N2–H2⋅⋅⋅O2, and N2–H2⋅⋅⋅O1 intramolecular H–bonds. All DFT calculations have been implemented at the B3LYP level with the 6–311G(d,p) basis set. The optimized molecular structure parameters have been compared with the experimental one in the solid phase. The energy gap, global chemical reactivity descriptor parameters, MEP, Fukui functions, DoS, NLO, and NBO analysis were also computed and investigated. The intermolecular interactions and their energies are evaluated using Hirshfeld surface and energy framework analyses. To determine …

Study Of Antioxidant Activity Of The Derivatives Of Quinoline-4-Carboxylic Acids By The Modification Of Isatin Via Pfitzinger Reaction, Sakti Hidayati Fikriya, Antonius Herry Cahyana

Makara Journal of Science

In this study, a quinoline-4-carboxylic acid derivative was synthesized through Pfitzinger reaction. In this reaction, isatin is modified via its reaction with ketone and refluxed for 24 h to obtain quinoline-4-carboxylic acid. The presence of a carboxylic group was identified by Fourier Transform Infrared (FTIR) spectroscopy and ultraviolet–visible (UV-Vis) spectrophotometry. The results showed that the absorption peaks of C=O and O–H stretching’s were detected in the range of 1724–1708 and 3436–3242 cm⁻¹, respectively. In the UV-vis spectrum, a shift in the absorption peak was observed toward a larger wavelength, which is referred as a bathochromic shift. The formation …

Investigation Of Challenging Transformations In Gold Catalysis, Qi Tang

USF Tampa Graduate Theses and Dissertations

This dissertation mainly contains three parts: 1) Divergent gold catalysis for alkyne trifunctionalization, encompassing three distinct modes to achieve the simultaneous formation of C-N, C-O, and C-C bonds in a single step 2) the study and development of a new method to synthesize azaborine derivatives; and 3) the construction of benzotriazole boranes (BTAB) as stable four-coordinate N-B heterocycles through gold-catalyzed alkyne hydroboration.

In the first part, alkyne trifunctionalization via divergent gold catalysis will be introduced. This novel approach involves a sequence of reactions that combine gold π-activation, vinyl gold nucleophilic addition, and gold (III) reductive elimination. By utilizing this methodology, …