Organic Chemistry Commons^™

Rate Acceleration Of Organocatalytic Ring-Opening Polymerization Rough The Application Of Bis- And Tris- ( Io)Urea H- Bond Donors, Samuel S. Spink

Senior Honors Projects

Well-defined and functionalized polymers have a wide variety of applications in biomedical studies. Advancements in the fields of drug delivery, microelectronics, and medical imaging, among other applications, are predicated upon the development of methods for the synthesis of precision polymers. Organocatalytic ring-opening polymerization (ROP) of cyclic monomers is an effective route to the production of polymeric materials, namely polyesters and polycarbonates, whose biodegradable properties make them a viable option in biomedical research. Arguably, H-bond mediated catalysts are among the most selective catalysts for ROP, giving rise to highly functionalized polycarbonates, well-controlled polymerizations, and other custom tailored applications. With respect to …

Conservative Tryptophan Mutations In Protein Tyrosine Phosphatase Ptp1b And Its Effect On Catalytic Rate And Chemical Reaction, Teisha Richan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protein-tyrosine phosphatases (PTPs) catalyze the hydrolysis of phosphorylated tyrosines by a 2-step mechanism involving nucleophilic attack by cysteine and general acid catalysis by aspartic acid. In most PTPs the aspartic acid resides on a flexible protein loop, consisting of about a dozen residues, called the WPD loop. PTP catalysis rates span several orders of magnitude, and differences in WPD loop dynamics have recently been show to correlate with the rate of enzymatic catalysis. The rate of WPD loop motion could possibly be related to a widely conserved tryptophan residue on the WPD loop. Therefore, point mutants were made in PTP1B …

Role Of Atp Hydrolysis And Mechanism Of Substrate Reduction In Nitrogenase, Sudipta Shaw

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen is essential for life on earth as it is a major constituent of amino acids and nucleic acids. Nitrogen gas (N₂) is the most abundant form of nitrogen in the atmosphere but the strong N≡N bond makes it unavailable for most organisms. Certain prokaryotes known as diazotrophs possess the unique ability to convert N₂ to ammonia (NH₃) which can be utilized by other organisms as a source of nitrogen. The diazotrophs perform this difficult reaction with the help of a complex metalloenzyme, nitrogenase. This enzyme is a major contributor of the fixed source of …

An Investigation Of The Kinetics And Equilibrium Chemistry Of Cold-Brew Coffee: Caffeine And Chlorogenic Acid Concentrations As A Function Of Roasting Temperature And Grind Size, Niny Z. Rao, Phd, Megan Fuller, Phd, Nicholas Parenti, Samantha Ryder, Nelly Setchie Tchato

CSHLA Scholar Day

Abstract:

Recently, both small and large commercial coffee brewers have begun offering cold-brew coffee drinks to customers with the claims that these cold-water extracts contain fewer bitter acids due to brewing conditions (Toddy website, 2016) while still retaining the flavor profile. Dunkin Donuts’ website suggests that the cold-water and long brewing times allow the coffee to reach “... its purest form.” With very little research existent on the chemistry of cold brew coffee consumers are left to the marketing strategies of Starbucks and other companies regarding the contents of cold-brew coffee. This research analyzes the caffeine and chlorogenic acid (3-CGA) …

Enediyne Derived Conjugated Polymers, Keda Hu

Chemistry and Chemical Biology ETDs

The advance of conjugated polymers (CPs) is largely relied on the development of new polymerization methods, the discovery of novel polymers that possess unique chemical and physical properties, and understanding of their structure-property relationship. We have employed a set of trans-enediynes (trans-EDYs) for the preparation of four series of CPs, polydiacetylenes (PDAs), platinum-segmented PDAs, polytriacetylenes (PTAs) and boron doped polyacetylenes (BPAs). The resulting polymers displayed interesting optical and electrochemical properties which could be fine-tuned by the attachment of various side chains on the EDY moieties. We have applied acyclic EDY metathesis for the synthesis of PDAs, a class of CPs …

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …

Spectrofluorometric Analysis Of Bisphenol-A In Drinking Water Bottles, Jeff Brochetti

Student Scholar Showcase

Spectrofluorometric Analysis of Bisphenol-A in Drinking Water Bottles

Bisphenol-A (BPA) is of environmental concern due to its ability to act as an endocrine disruptor in humans and many other animals. In the food industry, BPA is widely used in the production of plastic bottles and plastic liners in aluminum cans. Over time, trace amounts of BPA can leach from the container and into the contents inside. A new method of testing for trace amount of BPA involved the formation of an inclusion complex with ß-Cyclodextrin. With the formation of the inclusion complex, it becomes much easier to analyze low concentrations …

An Expedited, Regiospecific Para-Bromination Of Activated Aryls, Kathryn E. Dudley

Masters Theses & Specialist Projects

Electrophilic Aromatic Substitution (EAS) is one of the most frequently used aryl substitution methods. Aside from the fact that most EAS reactions require an acid and an oxidizer to proceed, the reactions involving activated aryls typically produce a mixture of ortho- and para- products as well as an ortho-/para- disubstituted product. Regiospecificity in aromatic substitution is key in the production of many compounds in a variety of disciplines. Since EAS is one of the most often used substitution methods, it is extremely important to develop an efficient method for regiospecific substitutions. Previous research developed a method of ortho-substitution by using …

Regiospecific P-Bromination Of Activated Aromatic Systems – Greener Approach, Elnaz Jalali

Masters Theses & Specialist Projects

The halogenated derivatives of heterocyclic compounds (haloarenes) are highly utilized in many fields of chemistry, including drug discovery, medicinal, and material chemistry. There are a variety of ways to functionalize an aromatic system and introduce halogen substituent into the ring. However, electrophilic aromatic substitution (EAS) has been the focus of growing attention, particularly for electronrich substrates.

Electrophilic aromatic bromination protocols are one of the most important electrophilic aromatic substitution reactions. However, preparation of bromoarenes classically recommends the use of highly oxidative agents along with utilizing various metal catalysts in a halogenated solvent. The corrosive and toxic nature of these reagents …

Investigating The Effects Of Pre-Laboratory Videos With Associated Questions On The Performance And Overall Laboratory Experience Of Organic Chemistry Students, Shareef Gamal Mohamed Kotb

Health Sciences Student Work

Background: Teachers struggle communicating ideas to students (Moreno et al, 2001). One of the aspects of teaching that’s most concerning is when students experience cognitive overload: the total effort exerted by working memory to grasp new information (Mayer, et al, 2002). The educational community found that introducing multimedia in learning minimizes cognitive overload (Mayer, et al, 2002). Little research has related to undergraduate chemistry classes, specifically the relationship between organic chemistry pre-laboratory multimedia and student learning. Purpose: The purpose of this capstone is to investigate the subjective efficacy of integrating pre-laboratory videos for lab preparation in an undergraduate organic chemistry …

Polychlorinated Biphenyls, Polybrominated Biphenyls, Polychlorinated Dibenzo-P-Dioxins And Polychlorinated Dibenzofurans, Prasada Rao S. Kodavanti, Joseph Valdez, Jae-Ho Yang, Margarita Curras Collazo, Bommanna G. Loganathan

Faculty & Staff Research and Creative Activity

Environmental contamination levels, human exposure, toxicokinetics, and health effects of PCBs, PBBs, PCDDs/PCDFs are discussed.

Ruthenium-Catalyzed Dehydrogenative And Dehydrative C-H Coupling Reactions Of Arenes With Alcohols And Carbonyl Compounds, Hanbin Lee

Dissertations (1934 -)

Despite their outstanding achievements, the requirement of preformed functional groups and wasteful byproduct formation are inherent disadvantages associated with the transition metal catalyzed cross-coupling methods. Inspired by the needs for green and sustainable chemistry, transition metal catalyzed dehydrogenative and dehydrative coupling methods have been recognized as environmentally sustainable and atom economical synthetic routes for the new C-C bond formation. The catalytic activation of C-H and C-O bonds allows the formation of coupling products from ubiquitous hydrocarbon substrates by releasing hydrogen or water byproduct. However, these novel protocols require relatively harsh conditions due to their low reactivity of C-H and C-O …

Synthesis And Study Of The Electrochemical And Optoelectronic Properties Of Π-Conjugated Poly-P-Phenylene-Based Molecular Wires, Anitha Boddeda

Dissertations (1934 -)

Organic photovoltaics will play an important role in supplementing the energy needs of the twenty first century in a most cost-effective way to convert the solar energy into usable forms of energy. One of the bottlenecks in promoting widespread use of photovoltaic devices for solar energy storage is the inefficiency of the devices, which in part arises due to the inefficient charge separation and long-range charge transport. Design and synthesis of efficient charge-transfer materials would require one to first identify and establish the structural features necessary in a given molecular wire, which may promote effective charge transfer to long distances. …

Computational Modeling Of S-Thiolation Reaction: Toward Discovering The Enzymatic Mechanisms Of Endogenous Hno Formation, Elena Ivanova

Dissertations (1934 -)

S-nitrosothiols (RSNOs) have long been proposed as potential sources of the elusive endogenous nitroxyl (HNO) via S-thiolation reaction with thiols. It is however not clear how S-thiolation can compete with the trans-S-nitrosation pathway commonly observed in vitro. Based on the insights into the highly unusual, antagonistic chemical nature of RSNO molecules, we hypothesize that, while difficult in vitro, S-thiolation could easily lend itself to enzymatic catalysis. To explore this possibility, we adopted a bottom-up computational approach that aims to identify possible catalytic mechanisms able to steer the RSNO + thiol reaction toward HNO production. Inspired by recent discovery of small …

Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day. Several analytical methods are employed to monitor the time series of the reaction, including (1) the derivatization of carbonyl (C═O) functional …

Stable Isotope Chemistry In Titan Haze Aerosol, Allison Wold, Thomas Gautier, Jennifer Stern, Joshua Sebree, Melissa Trainer

Research in the Capitol

Titan, a moon of Saturn, has a thick atmosphere made up of nitrogen and a few percent methane, with a surface pressure of 1.5x that of Earth. Titan’s atmosphere is believed to be that similar to that of early Earth before the rise of O2. One significant source of information on the history and evolution of the atmosphere is the measurement of stable isotopes of elements in the molecules of major gases such as nitrogen, methane, and higher order hydrocarbons. The fractionation associated with the formation of Titan aerosol analogs are explored in the laboratory as a function of environmental …

One-Pot Dialkylation Of Cycloalkanones And Their Ring-Closing Metathesis To Make Bridged Bicyclic Compounds, Dylan Sacenti, Ashley Yoon, Nathan Behrens

Seaver College Research And Scholarly Achievement Symposium

No abstract provided.

A Computational Study Of Lithium Carbamate Synthetic Intermediate Structures And Aggregation, Lawrence M. Pratt

Publications and Research

Computational quantum chemistry was used to investigate the structures of lithium carbamates in the gas phase and in ethereal solvents. These compounds act as nucleophiles with either inversion or retention of configuration at the chiral center and knowledge of the aggregation state is the first step in understanding the reactivity. The sterically hindered lithium phenyl carbamate is calculated to exist largely as the ether or THF solvated monomer in solution. Higher aggregates are possible in the gas phase, which is often taken as an approximation for solutions in non-polar solvents.

New Reaction Discoveries In Gold Catalysis, Seyedmorteza Hosseyni

USF Tampa Graduate Theses and Dissertations

In this dissertation, gold catalyst was employed to catalyze intermolecular reactions. Intramolecular reactions were far more advanced than intermolecular reaction in gold catalysis. With finding suitable ligands for gold catalysts, we were able to develop several transformations to synthesize interesting building blocks in organic chemistry including: allenes, furans, spiros, oxepines, propargyl ethers and ketones. These functionalities were synthesized by the use of triazole-gold(I) catalyst. Triazole, as a ligand bond to gold, showed enhanced stability of the catalyst, which resulted in better yields. Gold(I)/(III) redox chemistry also used for cyclopropanol ring openings which resulted in synthesizing substituted ketones.

Could O-Aminoquinones Of Estrogen Metabolites Serve As Platforms For Redox Cycling?, Rachel Miller

UNO Student Research and Creative Activity Fair

The metabolism of estrogen can lead to the formation of two isomeric o-quinones, estrogen-2,3-quinone (E-2,3-Q) and estrogen-3,4-Q (E-3,4-Q). The more reactive E-3,4-Q is genotoxic and can damage DNA by forming apurinic sites; whereas, E-2,3-Q does not form apurinic sites. Estrogen quinones may also be involved in redox cycling to produce reactive oxygen species (ROS), which is another genotoxic pathway. What is not yet clear, is why E-3,4-Q would undergo redox cycling while the non-carcinogenic E-2,3-Q would not. Nitrogen nucleophiles react with the E-3,4-Q at the 1-position. With DNA bases as the nitrogen (sp2) nucleophile, the adducts formed are catechols. We …

Synthesis Of Small Molecule Anti-Trypanosomal Drugs, Samuel Anderson

UNO Student Research and Creative Activity Fair

Demand for novel chemotherapeutic agents that treat Human African Trypanosomaiasis (HAT) persists. A series of compounds sharing a 3,4’diphephyl ether skeleton were prepared for a structure activity relationship (SAR) study evaluating antitrypansomal drug candidates. Trypanocidal assays performed in vitro by the Swiss Tropical and Public Health Institute identified a lead with an IC50 of 1.35 μg/mL analogous to a compound previously made in our laboratory. A slight improvement in activity (10%) was observed when changing the molecular substitution pattern from 4,4’ to 3,3’; however, the result is equivocal. Furthermore, in vitro test results demonstrated the weakness of amides as side …

Docking Studies Of Isoform-Selectivity Of Phosphatidylinositol 3-Kinase (Pi3k) Inhibitors, Kaitlin Goettsch

UNO Student Research and Creative Activity Fair

Phosphatidylinositol 3-kinases (PI3Ks) and their related pathways are reputed targets for drug-based anticancer therapies. Mutations in PI3K genes, expression, and pathways are frequent among multiple cancer types. Four isoforms of PI3Ks exist: α, β, γ, & δ and studies have identified several ligands for each isoform which are capable of serving as inhibitory therapeutic compounds. However, the biochemical efficacy of these molecules varies and the isoform selectivity is not well understood. In this study, we applied in silico docking methods and free energy calculation methods to estimate the binding of reported PI3K ligands against 5 PI3K structures: PI3Kα (PBD ID: …

Pd-Catalyzed Conversion Of Aryl Iodides To Sulfonyl Fluorides Using So2 Surrogate Dabso And Selectfluor, Nicholas Ball, Ariana L. Tribby, Ismerai Rodríguez, Shamira Shariffudin

Pomona Faculty Publications and Research

A one-pot Pd-catalyzed conversion of aryl iodide to aryl sulfonyl fluorides using DABSO and Selectfluor has been developed generating aryl sulfonyl fluorides in good to excellent yields. The reaction results in the generation of electronically and sterically diverse sulfonyl fluorides. Additionally, sulfonyl fluorides can be converted to aryl sulfonamides and sulfonic esters using Cs₂CO₃ under mild conditions.

Novel Trifluoromethylated 9-Amino-3,4-Dihydroacridin-1(2h)-Ones Act As Covalent Poisons Of Human Topoisomerase Iiα, Lorena Infante Lara, Alexis Sledge, Amine Laradji, Cosmas O. Okoro, Neil Osheroff

Chemistry Faculty Research

A number of topoisomerase II-targeted anticancer drugs, including amsacrine, utilize an acridine or related aromatic core as a scaffold. Therefore, to further explore the potential of acridine-related compounds to act as topoisomerase II poisons, we synthesized a series of novel trifluoromethylated 9-amino-3,4-dihydroacridin-1(2H)-one derivatives and examined their ability to enhance DNA cleavage mediated by human topoisomerase IIα. Derivatives containing a H, Cl, F, and Br at C7 enhanced enzyme-mediated double-stranded DNA cleavage ∼5.5- to 8.5-fold over baseline, but were less potent than amsacrine. The inclusion of an amino group at C9 was critical for activity. The compounds lost their activity against …

Palladium-Catalyzed Intramolecular Cross-Dehydrogenative Coupling: Synthesis Of Fused Imidazo[1,2‑A]Pyrimidines And Pyrazolo[1,5‑A]Pyrimidines, Siva K. Reddy Kotla, Jaya Kishore Vandavasi, Jeh-Jeh Wang, Keykavous Parang, Rakesh Tiwari

Pharmacy Faculty Articles and Research

A palladium-catalyzed intramolecular dehydrogenative coupling reaction was developed for the synthesis of fused imidazo[1,2-a]pyrimidines and pyrazolo[1,5-a]- pyrimidines. The developed protocol provides a practical approach for the synthesis of biologically important substituted pyrimidines from easily available substrates, with a broad substrate scope under mild reaction conditions.

Assessment Of Four Solvents For Extraction And Analysis Of The Chemical Composition Of Sansevieria Extrafoliar Nectar Drops By Gas Chromatography-Mass Spectrometry, Hope L. Juntunen, Patrick Videau, Donna Hazelwood, Michael Gaylor

Research & Publications

In the latter part of the 20th century, much effort was devoted to elucidating the chemical constituents of floral and extrafloral nectar secretions, with the primary aim of understanding their ecological roles, especially in regards to attracting pollinators. But, nearly all these studies focused on determining sugar and amino acid constituents. Only a few studies have reported more comprehensive assessments of the organic chemical constituents of plants, with none of those reporting such efforts for Sansevieria taxa (common houseplants known to purify air by bioaccumulating pollutants). To address this knowledge gap, we evaluated the efficacy of four organic solvents with …

Sequential Growth Of Molecular Complexity Via Alternating Ground State And Photochemical Reactions, Haibo Li

Electronic Theses and Dissertations

A new strategy of increasing molecular complexity by post photochemical oxidation followed by secondary intramolecular photochemical reaction is developed. It is based on the mild oxidation of photochemical generated alcohol by primary intramolecular cycloaddition of aromatic o-aminoaldehydes and a secondary intramolecular cycloaddition of aromatic o-aminoketone. Both cycloadditions are triggered via excited-state intramolecular proton transfer (ESIPT). Additionally, an efficient continuous reaction of photocatalyzed 2-nitrobenzyl alcohol intramolecular reduction and aryl nitroso Diels-Alder (NDA) reaction was discovered.

Design, Synthesis And Biological Evaluation Of Histone Deacetylase (Hdac) Inhibitors: Saha (Vorinostat) Analogs And Biaryl Indolyl Benzamide Inhibitors Display Isoform Selectivity, Ahmed Negmeldin

Wayne State University Dissertations

HDAC proteins have emerged as interesting targets for anti-cancer drugs due to their involvement in cancers, as well as several other diseases. Several HDAC inhibitors have been approved by the FDA as anti-cancer drugs, including SAHA (suberoylanilide hydroxamic acid, Vorinostat). Unfortunately, SAHA inhibits most HDAC isoforms, which limit its use as a pharmacological tool and may lead to side effects in the clinic. In this work we were interested in developing isoform selective HDAC inhibitors, which may decrease or eliminate the side effects associated with non-selective inhibitors treatment. In addition, isoform selective HDAC inhibitors can be used as biological tools …

Synthesis Of Netilmicin And Apramycin Derivatives For The Treatment Of Multidrug-Resistant Infectious Diseases, Amr Sayed Motawi Sonousi

Wayne State University Dissertations

The ever-growing bacterial resistance to existing antibiotics is alarming to humanity. Many researchers decided to revisit aminoglycosides with renewed emphasis on chemical modification as they have long been used as highly potent antibiotics for treating severe bacterial infections. The bactericidal effect of aminoglycosides is mainly due to protein synthesis inhibition by binding to the A-site of the bacterial ribosomes. However, the high potency and the broad spectrum of aminoglycosides has been outweighed by their side effects, especially ototoxicity, and by the resistance of pathogens. The goal of this research was the modification of existing aminoglycosides to develop derivatives which are …

Synthesis And Biological Activity Of Novel Tu100 Derivatives, Oladotun J. Alao

College of Graduate Studies: Theses & Dissertations

In an attempt to create more effective chemotherapeutic compounds, the naphthoquinone adduct, 12,13-dihydro-N-methyl-6,11,13-trioxo-5H-benzo[4,5]cyclohepta [1,2 b]naphthalen-5,12-imine (hereafter called TU100) was synthesized. Inspired by its unique and novel mechanism of action, a series of structural derivatives were synthesized to explore structure-activity relationships. The analogues exhibited different cytotoxicity profiles, revealing the indicated regions are involved in cell death induction. Furthermore, the analogues had dramatically different effects on cellular ATP production, suggesting different molecular targets. Synthesis, biological activity, and SAR study of these analogues will be revealed.