Chemistry Commons^™

Understanding The Selective Detection Of Homocysteine And Studies Toward The Synthesis Of Vinigrol, Dong Wang

LSU Doctoral Dissertations

The first part of the work is dedicated to the selective detection of Homocysteine (Hcy). In order to better understand this colorimetric detection method, a thermodynamic model for the pH dependence of the effective reduction potential of Hcy derived á-carbon radicals has been proposed. And using viologen indicators of varying reduction potentials, we demonstrate that colorimetric changes occur at experimental pH values consistent with the model. The one-carbon bridge stereochemistry of bicyclo[3.3.1]nonane framework is critical to make the third ring of the tricyclic precursor of vinigrol. We studied this stereochemistry carefully and found that the major diastereomer formed from Robinson …

Synthesis And Characterization Of New Symmetrical 3,6-Bis[(25,26,27- Tripropoxy-28-(3-(4-Iodophenyl) Propoxy)-P-Tert-Butyl Calix[4]Arene Ethynyl]-9h- Fluoren-9-One By Sonogashira Coupling As A Novel Precursor For Synthesis Of Quinodimethane (Qdm), Karim Akbari Dilmaghani, Fazel Nasuhi Pur

Turkish Journal of Chemistry

Novel symmetrical 3,6-bis[(25,26,27-tripropoxy-28-(3-(4-iodophenyl)propoxy)-p-tert-butyl calix[4]arene ethynyl]-9H-fluoren-9-one with a cone conformation was synthesized by palladium-catalyzed coupling of (25,26,27-tripropoxy- 28-(3-(4-iodophenyl)propoxy)-p-tert-butyl calix[4]arene and 3,6-diethynyl-9H-fluoren-9-one. Its structure was confirmed by FT-IR, ^1H-NMR, and ^{13}C-NMR spectroscopy, and elemental analysis and positive ion FAB mass spectrometry.

Synthesis, Crystal Structure, And Antioxidant Properties Of Novel 1,2,4-Triazol-5-Ones Containing 3,4-Dimethoxyphenyl And 3,4-Dihydroxyphenyl Moiety, Yasemi̇n Ünver, Sevgi̇ Meydanal, Kemal Sancak, Di̇lek Ünlüer, Reşat Ustabaş, Esra Düğdü

Turkish Journal of Chemistry

A series of new 4-(3,4-dimethoxyphenethyl)-5-akyl/aryl-2H- 1,2,4-triazol-3(4H)-ones (3a-g) was obtained by the reaction of ethyl 2-(ethoxy)(alkylidene/arylidene)hydrazinecarboxylate (1) and 2-(3,4-dimethoxyphen- yl)ethanamine (2). Compounds 4a-f and 5 were synthesized from the reaction of corresponding compounds 3a-f and 3g with BBr_3, respectively. With elemental analysis, IR, ^1H-NMR, and ^{13C-NMR spectral data, 14 newly synthesized compounds were characterized. The structure of compound 3a was inferred through IR, ^1H- and ^{13}C-NMR, elemental analysis, and X-ray spectral techniques. In addition, the newly synthesized chemicals were screened for their antioxidant properties. Among the chemicals tested, 4a, 4c, 4d, 4f, and 5 exhibited the highest degree of antioxidant activity.

Antiaromatic Dianions: Dianions Of Dixanthylidene By Reduction And Attempted Excited-State Deprotonation, Mary Black, Clifford Woodford, Nancy S. Mills

Chemistry Faculty Research

Reduction of dixanthylidene with potassium or lithium resulted in formation of the antiaromatic dianion in high yield. Attempts to form the dianion by excited-state deprotonation of dixanthene with n-butyllithium/TMEDA resulted in formation of the tetraanion from deprotonation ortho to the oxygen. Orientation of the sp3 hydrogens presumably allows preferential deprotonation of the xanthene rings.

A Concise Synthesis Of Β-Sitosterol And Other Phytosterols, Jiliang Hang, Patrick Dussault

Patrick Dussault Publications

A convenient synthesis of sidechain-modified phytosterols is achieved via a temporary masking of the stigmasterol 5,6-alkene as an epoxide. Following performance of the desired modification, the alkene is regenerated through a mild deoxygenation. The approach is applied to the syntheses of β-sitosterol and campesterol acetate, and suggests a facile route to the (Z)-isomers of Δ^22–23 phytosterols.

Includes Supplementary Data.

Characterization Of Stabilized Palladium Nanocatalysts, Meghann Broderick

Theses and Dissertations

Metal nanoparticles have received much interest for their application in catalysis due to high surface-to-volume ratios resulting in more available active sites. Ideally these catalysts are heterogeneous and allow for facile separation from the catalytic reaction mixture making them ideal for industrial application. Dispersed metal nanoparticles are explored due to their high reactivity in solution and are stabilized by surfactants and polymers. However, it is difficult to determine whether or not a catalyst is truly heterogeneous as a certain degree of leaching from the metal nanoparticle is inevitable. Determining the mechanisms involved in nanocatalysis is also a challenge. In this …

Synthesis, Characterization, And Deuterium Labeling Of Polyamides Studied By Nuclear Magnetic Resonance Spectroscopy, Christopher Allen Lange

Dissertations

The synthesis, characterization, and deuterium labeling of polyamides have been investigated. In Chapter II, selective deuterium labeling of various polyamides was demonstrated via a facile method which does not require organic solvent or catalyst. Quantitative solution-state NMR analysis showed deuterium incorporation at the carbon alpha to the carbonyl ranged from 20-75%. Incorporation in ε-caprolactam increased with repeated treatments. Isotopic shift effects for the deuterated materials were additive for all sites within experimental error.

In Chapter III, the effect of stoichiometric imbalances on the polymerization of poly(dodecamethylene terephthalamide)was investigated. Molecular weight was varied by polymerizing the monomer salt with excess diaminododecane, …

Synthesis Of Meta-Terphenyl Scaffolded Molecules For Catalysis And Sensor Applications, Brad Morgan

All Dissertations

The utility of the m-terphenyl has been observed in a wide variety of applications since its first discovery. The tunable conformational flexibility contributes to the unique properties and resulting applications thereof. Chapter 1 goes into detail about the concepts used throughout and defines the tools needed to understand the chemistry in the
resulting chapters.
The primary use of the m-terphenyl herein is as a canopy that shields a pocket created underneath the central ring. Functionalization within this pocket allows metal binding in defined coordination environments. with the use of donor ligands attached to the flanking rings. The applications of these …

Inhibitors Of NΑ-Acetyl-L-Ornithine Deacetylase: Synthesis, Characterization And Analysis Of Their Inhibitory Potency, J. Hlavacek, J. Picha, V. Vanek, J. Jiracek, J. Slaninova, V. Fucik, M. Budesinsky, Danuta M. Gillner, Richard C. Holz

Chemistry Faculty Research and Publications

A series of N ^α-acyl (alkyl)- and N ^α-alkoxycarbonyl-derivatives of l- and d-ornithine were prepared, characterized, and analyzed for their potency toward the bacterial enzyme N ^α-acetyl-l-ornithine deacetylase (ArgE). ArgE catalyzes the conversion of N ^α-acetyl-l-ornithine to l-ornithine in the fifth step of the biosynthetic pathway for arginine, a necessary step for bacterial growth. Most of the compounds tested provided IC₅₀ values in the μM range toward ArgE, indicating that they are moderately strong inhibitors. N ^α-chloroacetyl-l-ornithine (1g) was the best inhibitor tested toward ArgE providing an IC₅₀ value of 85 …

Novel Photochemical Methodologies For Diversity Oriented Synthesis And Screening Of Combinatorial Libraries, Roman Askatovich Valiulin

Electronic Theses and Dissertations

The main goal of this project was to develop an efficient methodology allowing rapid access to structurally diverse scaffolds decorated with various functional groups.

Initially, we discovered and subsequently developed an experimentally straightforward, high-yielding photoinduced conversion of readily accessible diverse starting materials into polycyclic aldehydes and their (hemi)acetals decorated by various pendants. The two step sequence, involving the Diels-Alder addition of heterocyclic chalcones and other benzoyl ethylenes to a variety of dienes, followed by the Paternò-Büchi reaction, was described as an alkene-carbonyl oxametathesis. This methodology offers a rapid increase in molecular complexity and diversity of the target scaffolds.

To develop …

Synthesis And Characterization Of Novel Triazol Compounds Containing A Thiophen Ring As Potential Antifungal Agents And The Structure Of 2-(2-Hydroxy-2-P-Tolyethyl)-5-(Thiophen-2-Ylmethyl)- 4-(4h-1,2,4-Triazol-4-Yl)-2h-1,2,4-Triazol-3(4h)-One, Yasemi̇n Ünver, Esra Düğdü, Kemal Sancak, Mustafa Er, Reşat Ustabaş

Turkish Journal of Chemistry

A series of new 4-(3,5-disubstitue-4H-1,2,4-triazol-4-yl)- 5-(thiophen-2-yl-methyl)-2H-1,2,4-triazol-3(4H)-ones (3a-c) were obtained by reaction N'-1-ethoxy-2-thiophen-2-yl-ethylydene hydrazino carboxylic acid ethyl ester (1) and 4-amino-4H-1,2,4-triazoles (2). 4-(3,5-disubstitue-4H-1,2,4-triazol-4-yl)-2-(2-oxo-2-arylethyl)-5- (thiophen-2-yl-methyl)-2H-1,2,4-triazol-3(4H)-ones (4a-e) and ethyl 2-(4-(3,5-disubstitue-4H-1,2,4-triazol-4-yl)-5-oxo-3-(thiophen-2-ylmethyl)- 4,5-dihydro-1,2,4-triazol-1-yl)acetates (6a-c) were obtained by reaction of compounds 3 and bromoacetophenon derivatives and bromo ethylacetate, respectively. Compounds 5a-e were synthesized from the reaction of corresponding compounds 4a-e with NaBH_4. Compounds 7a-c were obtained by the reaction compounds 6 and LiAlH_4. Seventeen new compounds were synthesized and characterized by elemental analyses, IR, ^1H-NMR, and ^{13}C-NMR spectral data. The structure of compound 5d was inferred through IR, ^1H-, ^{13}C-NMR, elemental analyses, and X-ray spectral techniques. …

Solid Phase Amide Synthesis Using Staudinger-Vilarrasa Coupling And Microwave Irradiation, Ryan Patrick Schmidtz

Undergraduate Honors Thesis Collection

Amide bond formation is an already well documented area of organic chemistry, and is very useful in its application in medicine and pharmaceuticals. However, current methods have not been investigated with regards to optimization of reaction times, solvents, and energy sources. In addition, current methods also utilize toxic solvents to cleave the peptide from the solid phase resin. In our study, we combine the Staudinger and Vilarrasa coupling reactions with microwave irradiation to develop and optimize the synthesis of amide bonds through the use of a solid support. Instead of attaching the peptide to the solid support, our amide bond …

Synthetic Studies Of Laulimalide Analogues, Ian Addison Mcalexander

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chapter 1 provides some background information on the disease area of cancer and current modes of treatment. Chemotherapy treatment is discussed with a focus on the major cellular targets for these drugs: DNA and microtubules. For each target, classes of active compounds are described along with their mode of action. The microtubule stabilizing agent laulimalide is introduced and a case is made for analogue synthesis.

Chapter 2 describes our first generation efforts toward synthesis of des-methyl laulimalide. The target compound is divided into a northern and southern fragment with the synthesis of each fragment described. The preparation of landmark intermediates …

Task Specific Ionic Liquids For Enantiomeric Recognition And Nanomaterials For Biomedical Imaging, David Kipkogei Bwambok

LSU Doctoral Dissertations

Ionic liquids (ILs) are organic salts that melt at or below 100°C. Interest in ILs continues to grow due to their unique properties such as lack of measurable vapor pressure, high thermal stability, tunability and recyclability. The first part of this dissertation explores the use of chiral ionic liquids (CILs) for enantiomeric recognition of chiral analytes using fluorescence spectroscopy. Chiral analyses continue to be a subject of considerable interest primarily as a result of legislation introduced by the Food and Drug Administration. This has led to an increased need for suitable chiral selectors and methods to verify the enantiomeric forms …

Synthesis And Leishmanicidal Evaluation Of Novel 4-Substituted-2,2-Dimethyl-7-(Prop-2-Ynyloxy)Chromenes, Babak H. Alizadeh, Alireza Foroumadi, Susan K. Ardestani, Fatemeh Poorrajab, Abass Shafiee

Turkish Journal of Chemistry

Substituted 4-chromenes were synthesized via the Grignard coupling reaction of various substituted phenyl- and benzylmagnesium chlorides with 2,2-dimethyl-7-(prop-2-ynyloxy)chroman-4-one (1) in relatively good yield (60%-85%). The benzylic-substituted derivatives were a mixture of 2 exo and endo regioisomers, and the exo compounds were a mixture of E and Z isomers. Structural analysis of the exo and endo isomers, as well as E and Z of exo isomers were based on H-NMR, ^{13}C-NMR, and NOESY experiments. The synthetic compounds were examined for in vitro activity against Leishmania major and compound 9 (a, b) was the most active, with inhibitory activity of 36%.

Cationic Exchange Reactions Involving Dilithium Phthalocyanine, Morgan M. Hart

Browse all Theses and Dissertations

Dilithium phthalocyanine (Li₂Pc) consists of an aromatic macrocycle possessing a doubly negative charge and two Li⁺ counterions. One Li⁺ ion is easily displaceable while the other remains coordinated to the phthalocyanine ring. The displaceable Li⁺ cation can be exchanged with other cations, such as a singly charged tetra-alkyl ammonium cation, by using several variations of a general procedure. It has been demonstrated that tetraalkylammonium lithium phthalocyanines (TAA-LiPcs) can be successfully and reproducibly synthesized with yields ranging from 54.5% up to 64.3%. All TAA-LiPcs demonstrated poor solubilities from approximately <0.2 mg/mL to 5 mg/ml in the solvents tested (with the exception of tetrapropylammonium lithium phthalocyanine and tetrahexylammonium lithium phthalocyanine). All of the TAA-LiPcs synthesized were dark-purple in color, with the exception of tetraheptylammonium lithium phthalocyanine and tetraoctylammonium lithium phthalocyanine. These two compounds were dark - blue in color. Melting points varied greatly from >370.4°C to 157.9°C and depended greatly upon …

Synthesis Of Substituted 2-Amino-Cyclobutanones, Nicola Armoush, Preeti Syal, Daniel P. Becker

Chemistry: Faculty Publications and Other Works

A series of weakly nucleophilic nitrogen derivatives including carbamates, amides, sulfonamides, and anilines were reacted with 1,2‐bis(trimethylsilyloxy)cyclobutene under acidic conditions to afford various substituted 2‐aminocyclobutanone derivatives 3a–i in modest to excellent yields.

Synthesis And Characterization Of Acylphosphine Oxide Photoinitiators, Hany F. Sobhi

ETD Archive

Recently, polymerization science has assumed an increasing relevance in many applications, including orthopedic and dental biomaterials. Current technologies are based on the use of photochemically reactive systems, which are suited to absorb light to produce primary radical species capable of initiating polymerization. Acylphosphine oxides and acylphosphonates are known to be very effective photoinitiators for various unsaturated polymeric systems. The high reactivity observed was ascribed to the phosphinyl and phosphinoyl radicals generated. Because of the poor qualities of other initiators, we examined new routes to synthesize acylphosphine oxide initiators to achieve compatibility with aqueous media and improved performance. The preparation and …

Understanding The Application Of Supported Palladium Catalysts In The Suzuki-Miyaura Cross-Coupling Reaction, Lubabalo Tseliso Bululu

Seton Hall University Dissertations and Theses (ETDs)

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Novel Approach For Synthesis Of 2:1 Permethylated Β-Cyclodextrin–C60 Conjugate, Zhu Guan, Yali Wang, Yong Chen, Yongmin Zhang

Department of Chemistry: Dissertations, Theses, and Student Research

Amphiphilic cyclodextrin–fullerene conjugates have potential biological activity, due to their water solubility. In order to study the influence of the linker of these conjugates on solubility and aggregation, a permethylated β-cyclodextrin–C₆₀ conjugate with a short linker –(CH₂)₂NHCO–, which is attached to the secondary face of β-cyclodextrin was synthesized. Its solubility in water and its UV spectrum in CH₂Cl₂ and water were investigated.

Size-Controlled Synthesis Of Monodisperse Core/Shell Nanogels, William H. Blackburn, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Small, monodisperse nanogels (similar to 50-nm radius) were synthesized by free-radical precipitation polymerization and were characterized using a suite of light scattering and chromatography methods. Nanogels were synthesized with either N-isopropylacrylamide or N-isopropylmethacrylamide as the main monomer, with acrylic acid or 4-acrylamidofluorescein as a comonomer and N,N'-methylenebis(acrylamide) as a cross-linker. By varying the surfactant and initiator concentrations, particle size was controlled while maintaining excellent monodispersity. An amine-containing shell was added to these core particles to facilitate subsequent bioconjugation. Successful conjugation of folic acid to the particles was demonstrated as an example of how such materials might be employed in a …

The Selective Synthesis Of Oxacalix[6]Arenes And The Exploration Of Azacalix[N]Arenes, W. Christian Crannell

Honors Theses

Calix[n]arenes, cyclIc molecules composed of "n" benzene rings meta-linked by a methylene to form a macrocycle, are very prevalent jn the literature and enjoy a wide range of applications. However, the oxygen bridged and nitrogen bridged systems, oxacalllx[n)arenes and azacalix[n]arenes, respectively, are far less common because they are synthetically challenging. Furthermore, the selective synthesis of oxacalix[6]arene systems has not previously been well documented, but the systems can now be accessed in a facile approach disclosed here. The insight and knowledge gained from the synthesis of oxacalix{6]arenes has provided a foray into the synthesis of azacalix[nlarenes.

Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia

Theses and Dissertations

Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …

Selective Synthesis Of Oxacalix[6]Arenes And Mixed Oxacalix[4]Arenes, Christian Crannell

Undergraduate Research Symposium (UGRS)

Calixarenesare macrocycles composed of benzene rings meta linked to each other by one carbon atom. These exotic compounds can be used for a variety of purposes including metalleaching for environmental cleanup, surface technology, luminescent probes, nuclear waste treatment, among others. A variety of calixarenesexist, including azacalix[n]arenesthiocalix[n]arenes(where n = the number of benzene rings) and oxacalix[n]arenes; these macrocycles use nitrogen, sulfur and oxygen, respectively, as the atom whichlinks the benzene rings together. My research has focused on synthesizing oxacalix[6]arenes (“hexamer”) in high yield, which is a synthetic challenge because it is generally accepted that oxacalix[n>4]arenes will thermodynamically decompose to the …

Synthesis And Characterisation Of Tetra-Tetrazole Macrocycles, Andrew Bond, Adrienne Fleming, Fintan Kelleher, John Mcginley, Vipa Prajapati, Signe Skovsgaard

Articles

The syntheses of tetra-tetrazole macrocycles, containing two bis-tetrazole units linked by a variety of alkyl chain lengths from four to eight carbons, are described. The crystal structures of three of these derivatives are reported, and the molecular conformation in the solid state is compared to that of one previously reported tetra-tetrazole macrocycle and to other bis- and tris(tetrazole)benzene structures. The macrocycle conformation is influenced by the length of the alkyl chain linker, the relative orientation of the tetrazole rings on the benzene ring, and by intermolecular interactions. In the macrocycles based on 1,2-bis(tetrazole)benzene, the adjacent tetrazole rings on the benzene …

Air And Water Free Solid-Phase Synthesis Of Thiol Stabilized Au Nanoparticles With Anchored, Recyclable Dendrimer Templates, John D. Gilbertson, G. Vijayaraghavan, K. J. Stevenson, Bert D. Chandler

Chemistry Faculty Research

Solid-phase synthetic templates for Au nanoparticles were developed using Merrifield resins and polyamidoamine (PAMAM) dendrimers. This synthetic scheme affords the opportunity to prepare metal nanoparticles in the absence of air and water, and it does not necessitate phase transfer agents that can be difficult to remove in subsequent steps. Amine-terminated generation 5 PAMAM (G5NH2) dendrimers were grafted to anhydride functionalized polystyrene resin beads and alkylated with 1,2-epoxydodecane to produce G5C12anch. The anchored dendrimers bound both CoII and AuIII salts from toluene solutions at ratios comparable to those of solution phase alkyl-terminated PAMAM dendrimers. The encapsulated AuIII salts could be reduced …

Xanthene/Benzoxanthene Dyes: Novel Synthetic Metholologies, Applications In Molecular Recognition, Cellular Imaging And The Design Of A Tunable White (Rgb) Light Emitter, Youjun Yang

LSU Doctoral Dissertations

My graduate work has focused on the development of new fluorophore materials towards addressing several interdisciplinary research problems. Selective detection of sialic acid via a boron-amide interaction. Concentration changes of sialic acid can be monitored ratiometrically in the visible region using a boronic acid based chemosensor. The technique shows great promise for the detection of sialic acid, a critical cell surface residue involved in cancer, graft rejection and virulence in certain bacteria. There is no interference from commonly occurring oligosaccharides, aminosugars and most carboxylic acid-containing compounds. Improved synthetic methodology and studies of novel molecular probe architectures. I have developed a …

Synthesis And Characterization Of Highly Conductive Polypyrrole And Polypyrrole/Lignosulfonate/Graphite Composites, Aopeau Imvittaya

Theses and Dissertations

Polypyrrole (PPy) is one of the conductive polymers frequently used in commercial applications, mainly due to its long-term stability and the possibility of forming homopolymers or composites with optimal properties. Polypyrroles were prepared by the chemical polymerization of pyrrole using various methods. The effects of several parameters such as oxidant, dopant type, additives and reaction conditions on the properties of PPy were investigated. In addition, PPy/graphite composites were prepared because graphite is highly conductive and effectively incorporated into the polymer matrix during the polymerization. The amount of graphite in the composite was varied to determine the maximimum conductivity achievable in …

Synthesis And Functionalizations Of Tetrapyrrole Derivatives, Lijuan Jiao

LSU Doctoral Dissertations

Chapter 1 of this Dissertation presents a brief overview of the history of tetrapyrrole derivatives and of their fundamental properties. Overviews of porphyrins, benzoporphyrins, chlorins and porphycenes are presented. Work presented in Chapter 2 through Chapter 4 mainly focuses on the syntheses and functionalization of chromophore-extended porphyrin derivatives. Several new synthetic routes for the syntheses and functionalizations of extended porphyrins either at the β-position or at the meso-position of porphyrin are developed. From these improved synthetic routes, the regio-selective syntheses of porphyrin derivatives are described. Chapter 2 mainly focuses on the syntheses of β,β'-fused methylenepropanoporphyrins and related porphyrin dimers. Chapter …

Structure-Activity Studies Of Glycosphingolipids As Antigens Of Natural Killer T Cells, Randal Donald Goff

Theses and Dissertations

Glycosphingolipids (GSLs), composed of a polar saccharide head and a lipophilic ceramide tail, are ubiquitous components of the plasma membrane of eukaryotic cells. They serve in many regulatory capacities and have antigenic properties towards natural killer T (NKT) cells of the innate immune system. Critical to the recognition of glycosylceramides by NKT cells are antigen presenting cells (APC), such as dendritic cells, which are responsible for binding, processing, and delivery of ligands to these lymphocytes. This event is mediated by CD1d, a major histocompatibility complex-like protein expressed on the surface of APCs, which binds GSL antigens by the ceramide moiety …