Organic Chemistry Commons^™

The Quantification Of Cocaine From The Erythroxylum Coca Plant And The Comparison On High Performance Liquid Chromatography And Gas Chromatography Mass Spectroscopy As An Analytical Method., Tuesday James

Student Theses

Cocaine is derived from the Erythroxylum coca plant, is a highly addictive stimulant abused all over the world. There are two types of Erythroxylum coca plants that produce cocaine; the E. Coca and E. Novogranatense. Cocaine exists as the salt, and the freebase which is typically referred to as “crack” due to the crackling sound it makes when heated. It is popular because it is inexpensive and easily available on the streets, mainly in poor urban areas. The purpose of this project was to determine the amount of cocaine that can be extracted from E.coca and to assess which analytical …

Solid-Phase Peptide Synthesis Of Analogues Of The N-Terminus A-Ring Fragment Of The Lantibiotic Nisin: Replacements For The Dehydroalanine (Dha) Residue At Position 5 And The First Incorporation Of A Thioamide Residue, Kim Manzor, Keith Ó Proinsias, Fintan Kelleher

Articles

A number of A-ring analogues of the lantibiotic nisin, containing replacements for the Dha at position 5, have been successfully prepared by solid-phase peptide synthesis. The Dha replacements include glycine, alanine, phenylalanine, serine and 1-aminocyclopropyl carboxylic acid (ACCa). The incorporation of a thioamide-isoleucine residue at position 4 is also described and is the first report of the preparation of a lantibiotic ring fragment containing a thioamide link.

Olfactory Receptor Antagonism In The Or-I7 Aldehyde Receptor And The Mammalian Olfactory System, Min Ting Liu

Dissertations, Theses, and Capstone Projects

The detection of smell is initiated when an odorant binds and activates olfactory receptors (ORs) within the nose. Chapter 1 studies the structural requirements for activation of the OR-I7 aldehyde receptor. Octanal is an agonist of the OR-I7 receptor. 4-Ethylcyclohexylacetaldehyde (1.1), with a cyclohexyl ring that locks the C4-C5 bond of octanal in the gauche conformation, was previously found to have higher potency than octanal, suggesting that the OR-I7 receptor prefers the gauche conformation of octanal during activation. However, 1.1 had only been previously tested as a mixture of cis- and trans-isomers, and therefore, it was …

From The Making To The Tuning To The Use Of Chlorins For Biomedical Applications, Junior Gonzales

Dissertations, Theses, and Capstone Projects

Chlorins are porphyrins missing a double bond. These pigments are optimal platforms for the development of novel dyes that display drug-like attributes such as photodynamic therapy (PDT) agents. More recently, it was demonstrated that chlorins can serve both as a PDT agent and as a modality for fluorescence or PET imaging. Thus, multifunctional chlorins eliminate the differences that may occur in specificity, uptake, and distribution between separate compounds or constructs for imaging and therapy. The overall goal of this dissertation is to take advantage of the reputed intrinsic attributes of chlorins as a viable tool in biomedical applications. In this …

The Modified Stereospecific Stille Reaction: Palladium-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Carbastannatranes, Chao-Yuan Wang

Dissertations, Theses, and Capstone Projects

Organic chemistry is present in all domains of everyday life, from polymer production to medicine. In order to synthesize complex compounds, it is often necessary to make new carbon-carbon bonds. Transition metal catalysts, particularly those derived from second and third row metals such as Pt, Pd, Rh, and Ir metals, display remarkable efficiency for the formation of carbon-carbon and carbon-heteroatom bonds. In the first chapter, introduction of transition metal-catalyzed cross-coupling reactions is given. While the formation of C(sp²)–C(sp²) bonds has been studied extensively, C(sp³)-C(sp²) bond formation still presents a challenge due to …

Conformational Studies Of Gram-Negative Bacterial Quorum Sensing 3-Oxo N-Acyl Homoserine Lactone Molecules, Darren Crowe, Alan Nicholson, Adrienne Fleming, Ed Carey, Goar Sanchez-Sanz, Fintan Kelleher

Articles

In their ¹H NMR spectra in CDCl₃ 3-oxo-N-acyl homoserine lactones (OHLs) show significant downfield chemical shifts of the amide N-H proton when compared to the parent N-acyl homoserine lactones (AHLs). NMR spectroscopic and DFT calculation studies have shown that this is most likely due to the presence of a stabilising intramolecular H-bond from the N-H to the 3-oxo group. The ¹H NMR spectra also show evidence for the enol tautomers and that the amount of enol present for a range of OHLs is 4.1-4.5% in CDCl₃ and 6.5-7.2% in CD₃CN. In …

Design, Synthesis And Glioblastoma Activity Of 1,3-Diazinane Based Aryl Amides And Benzo Fused Heterocycles, Rebecca Hron

LSU New Orleans Theses and Dissertations

The development of novel targeted therapeutics for the treatment of cancer remains difficult due to the complex nature of the disease itself as well as the challenges associated with the synthesis of these therapeutics. Impediments to the discovery of novel drug candidates include lack of available starting materials and access to well-developed syntheses which are both convenient and economically feasible. Semicarbazides, for instance, are a critical synthon for the manufacture of numerous biologically important molecules. Historically, convenient methods for the synthesis of semicarbazides and their derivatives did not exist. Recently, a facile and efficient method for the preparation of semicarbazides …

Studies Directed Towards The Iridium Catalyzed Synthesis Of New Carbon-Nitrogen Bonds., Maria Lindsay

LSU New Orleans Theses and Dissertations

Amines are ubiquitous in nature and serve a variety of functions in living organisms. Because of this fact amines are of great biological and pharmaceutical interest. The iridium catalyst (pentamethylcyclopentadienyl) iridium dichloride dimer ([Cp*IrCl₂]₂) has been used in a number of ways to synthesize new carbon-nitrogen bonds. These studies were directed toward the development of a method for the iridium catalyzed N-alkylation of alpha-amino acid esters as well as the development of a strategy for synthesis of the natural product 275A.

We have optimized a method for the N-alkylation for alpha-amino acid esters. Using this …

C(Sp2)–H Functionalizations Employing 2-Aminophenyl-1h-Pyrazole As A New Removable Directing Group, Wan-Chen Lee

Master's Theses

2-Aminophenyl-1H-pyrazole (2-APP) was discovered as a novel removable bidentate directing group for copper-mediated aerobic oxidative C(sp2)–H bond amidation and sulfonamidation bearing a wide range of sulfonamides, When Cu(OAc)2 was employed as the copper source, 1,1,3,3-tetramethylguanidine (TMG) as an organic base, the reaction, optimally carried out overnight in DMSO at 80 °C in open air, produced a variety of products in moderate to excellent yields. In addition, C(sp2)–H bond chlorination has been developed by using this auxiliary, employing trichloroacetamide as a new chlorine source. Furthermore, this unprecedented directing group also can assist copper-mediated regio-selective hydroxylation, and ortho-alkynylation/annulation by using Cu(OAc)2 as …

Synthesis Of Pyranobenzopyrans, Sumiea B. Eltayeb

Seton Hall University Dissertations and Theses (ETDs)

Carbohydrates and their derivatives are involved in a wide array of biological processes and are crucial for the survival of living entities. As a result, sugar-based compounds have become attractive scaffolds for drug design. In addition, pyranobenzopyran derivatives have shown promise in the treatment of numerous health conditions such as anticoagulants, antifungal, and anti-inflammatory agents. They have also shown important properties as antibiotics anti-AIDS agents) and antitumor drugs. The main point of our research was to determine and develop a synthetic method for the preparation of pyranobenzopyrans and carbohydrate fused heterocyclic compounds. This was accomplished via a [4+2] cycloaddition reaction …

Synthesis Of Α, Β-Substituted Alkenylphosphonates From Α-Phosphonovinyl Triflates: I) Palladium Catalyzed Suzuki-Miyaura Cross-Coupling With Aryl Boronic Acids Ii) Palladium Catalyzed Reduction, Ronald Laryea Mensah

Master of Science in Chemical Sciences Theses

Alkenylphosphonates (vinylphosphonates) are important targets for R & D because they have interesting chemical, biological and pharmacological properties. Vinylphosphonates are used in synthesis, polymer applications, and have demonstrated potential as anticancer and antimicrobial agents.

Vinyl triflates are useful in organic synthesis and are referred to as pseudo-halides because they react in a manner similar to halides. Vinyl triflates have a broad range of synthetic utility because they undergo nucleophilic substitutions and transition metal-mediated reactions. There is a growing interest in using α-phosphonovinyl pseudo-halides in transition metal-mediated cross-coupling reactions as a means to synthesize α, β-substituted alkenylphosphonates. Over the past three …

A Complex Stereochemical Relay Approach To The Antimalarial Alkaloid Ocimicide A1. Evidence For A Structural Revision, H. Nikolayevskiy, M. K. M. Tun, Paul R. Rablen, C. B. Mamoun, S. B. Herzon

Chemistry & Biochemistry Faculty Works

Ocimicide A1 (1) and the semisynthetic derivative ocimicide A2 (2) are highly potent antimalarial agents efficacious against chloroquine-sensitive and -resistant Plasmodium falciparum strains with IC50 values in the nanomolar and picomolar range, respectively. Members of this family have demonstrated radical cure in rhesus monkeys, without detectable toxicity, but their structure–function relationships and mechanism of action are unknown. Herein we describe a twelve-step synthesis of an advanced N-acylated pentacyclic precursor to the proposed structure of 1 (11% overall yield). Instability and poor P. falciparum growth inhibition of the corresponding free donor–acceptor cyclopropylamine, and large discrepancies between reported and both experimental and …

Synthesis And In-Vitro Cell Viability/Cytotoxicity Studies Of Novel Pyrrolobenzodiazepine Derivatives, John M. Jarrett

Undergraduate Honors Theses

Pyrrolobenzodiazepines (PBDs) are a group of naturally occurring compounds that were discovered in the cultures of Streptomyces in the 1960s. Some natural PBDs discovered in these cultures, such as anthramycin and sibiromycin, were shown to possess a broad spectrum of anti-tumor activity. Since cancer is still a leading cause of death globally, the development of novel anti-proliferative derivatives of PBDs is essential for human welfare worldwide. Further synthesis and structure-activity relationship (SAR) studies of the parent natural products and their tetracyclic analogs will lead to the discovery of drug candidates. In this work, thirteen PBD analogues were synthesized using no …

Development Of Recyclable Gold Nanoparticles For Routine Benchtop Catalysis In Organic Transformations., Shengzong Liang

Electronic Theses and Dissertations

Homogeneous gold catalysis is a popular research area due to its high efficiency. Various gold catalysts have been utilized in organic synthesis and their reaction mechanisms are also well understood. However, most gold catalysis suffers from high catalyst loading or catalyst decay problems. In addition, homogeneous gold catalysts are not recyclable. These disadvantages have limited their application in large-scale synthesis and also caused a serious waste of this precious metal. A solution for these problems is to use a recyclable heterogeneous gold catalyst. So in this study, with the aim of making gold chemistry greener we successfully used heterogeneous gold …

Genetically Encoded Fluorescent Protein Biosensor For Nitric Oxide, Wenjia Zhai

Department of Chemistry: Dissertations, Theses, and Student Research

Nitric oxide (NO) is an important molecule in living cells for signaling, thus a specific sensor to detect its level in live cells is needed. Currently there are a few small molecule probes for the detection of NO. A common shortcoming of these probes is their unavoidable leakage from the target cells. In this project, I seek to develop a novel green fluorescent protein (GFP)-based biosensor to detect cellular NO. This GFP-based sensor is genetically encodable and can potentially avoid the possible false positive result due to the leakage. I synthesized an unnatural amino acid (unAA) and examined its incorporation …

Advancing Structure-Property Relationships In Functional Materials Via Thiol-Ene Photopolymerization, Brian Richard Donovan

Dissertations

Thiol-ene photopolymerizations provide a robust and versatile synthetic pathway to functional materials, and owing to the radical step-growth nature of polymerization and the resulting homogenous network structure, provide non-convoluted insight into how network chemistry influences and dictates macromolecular properties.

The first facet of this dissertation focuses on the design and synthesis of bio-inspired, thin film adhesives for dry and aqueous adhesion. Drawing inspiration from the intertidal marine mussel, Chapter II details the synthesis of adhesive networks containing a monofunctional catechol-based monomer. The inclusion of a catechol group resulted in significant improvements in adhesion on a variety of substrates. In Chapter …

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) …