Physical Sciences and Mathematics Commons^™

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 …

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 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 …

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.

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

Seton Hall University Dissertations and Theses (ETDs)

.

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 …

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 …

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 …

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 …

Synthesis Of Aspernigrin A, Erica Joerger

Undergraduate Theses and Capstone Projects

Aspernigrin A is a compound correlated with inhibiting the growth of cancer cells in the colon. A five-step synthesis was designed for aspernigrin A, projected to yield four intermediates and the final product. The intermediates were analyzed by high field 1HNMR and FT-IR spectroscopy before proceeding to the next step. A model pyridone ring system was successfully prepared from a commercially available pyrone precursor in two steps. These results provide a proof of concept that the synthetic scheme should successfully yield the natural product.

Synthesis Of Novel Antimycobacterials And A Fluorescent Sensor For Simple Carbohydrates, Brian Thomas Walker

Theses and Dissertations

Cell surface carbohydrates play an important role in a wide variety of biological processes such as inflammation, tumor metastasis, and viral and bacterial infection. The goal of our research has been two-fold. The first objective was the synthesis of antimycobacterial compounds. A mannose containing tetrasaccharide from the mannan core of lipoarabinomannan (LAM) of Mycobacterium tuberculosis has been synthesized using α-D-methylmannopyranoside as starting material and Koeings-Knorr reactions to couple saccharides. The synthesis was completed in nine steps and in 14% total yield. This compound should be useful in competitive inhibition studies with macrophages or as an immunological marker. We have successfully …

The Synthesis Of Biomimetic Tungsten And Molybdenum Complexes, John Sterling Cole Iii

Honors Theses

The synthesis of novel biomimetic molybdenum and tungsten compounds that are potential model complexes for molybdenum and tungsten oxidase enzymes is being pursued. Model complexes such as these provide a better understanding of the basic chemistry of a metal center in an environment similar to that found in particular enzyme active sites. This understanding provides a good starting point for biologists or biochemists studying those biological systems. The first target complex will incorporate a tetradentate-S4 ligand (L) that features two biphenyl-S2 fragments joined by a propyl linker. The second target complex will incorporate a bidentate ligand (L') with a singly …

Synthesis, Characterizations, And Evaluation Of New Reactive Two-Photon Absorbing Dyes For Two-Photon Excited Fluorescence Imaging Applications, Katherine J. Hales

Electronic Theses and Dissertations

Recent, cooperative advances in chemistry, biology, computing, photophysics, optics, and microelectronics have resulted in extraordinary developments in the biological sciences, resulting in the emergence of a novel area termed 'biophotonics'. The integrative and interdisciplinary nature of biophotonics cuts across virtually all disciplines, extending the frontiers of basic cellular, molecular, and biology research through the clinical and pharmaceutical industries. This holds true for the development and application of the novel imaging modality utilizing multiphoton absorption and its extraordinary contribution to recent advances in bioimaging. Intimately involved in the revolution of nonlinear bioimaging has been the development of optical probes for probing …

Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi

LSU Doctoral Dissertations

Novel symmetric and asymmetric water-soluble tetrabenzoporphyrin are synthesized in relatively good yields. These compounds are synthesized by the condensation of butanopyrrole with several aldehydes that contain masked water solubilizing groups followed by metal insertion, oxidation and demetallation and deprotection of the masked solubilizing groups. The biological evaluation (in vitro and in vivo) studies are described in addition to the photophysical evaluations of the corresponding compounds. A novel versatile route to the syntheses of novel free-bases and metallo-benzoylbiliverdin is discussed. The treatment of metal free-dodecasubstituted porphyrin with sodium nitrite and trifluoroacetic acid at room temperature in the presence of oxygen affords …

The Stereoselective Synthesis Of The Butyrolactone-Bridged [8-5-5] Tricyclic Ring Systems Of (+/-)-Asteriscanolide Via The Titanium-Mediated Hetero-Pauson-Khand Reaction, Mohamed G. Sherriff

LSU Doctoral Dissertations

The stereoselective construction of the tricyclic ring system of asteriscanolide from cyclooctadiene has been achieved. The synthesis involves two main steps; the synthesis of the aldehyde precursor(5)and the titanium-mediated cabocyclization of 5 to make the three rings of 43 stereoselectively.

The Synthesis And Characterization Of Bicyclooxacalixarenes, Kevin J. Selby

Honors Theses

Bicyclooxacalixarenes were synthesized in high yield via a selective, room temperature Sn Ar reaction of phluoroglucinol with 2,6-dichloropyridines. Functionality on the 2,6-dichloropyridioe was varied by changing the electron-withdrawing groups in the 3 and 5 positions (using chlorine, nitro groups, and cyano groups) and the side-chains in the 4-position (using ethyl, butyl, phenyl and ρ-tolyl groups). The resulting cage-like molecules were studied by X-ray crystallography and tested for metal complexation.

The Syntheses Of Novel Indicators And Materials For Chiral Separation, Rolanda Johnson

LSU Doctoral Dissertations

The colorimetric properties of resorcinarene solutions had not been fully investigated since von Baeyer's initial synthesis. We find that the solutions containing resorcinarene macrocycles develop color upon heating or standing. In the presence of saccharides, these solutions exhibit significant color changes which are readily observable by visual inspection. We determined that the solution color is due to macrocycle ring opening and oxidation. The optical responses to saccharides are due to complexation of the sugar with the acyclic chromophores. We have applied these mechanistic insights towards the challenging problems of the visual detection of saccharides and other important biologically analytes. In …

Synthesis And Antibacterial Assessment Of Water-Soluble Hydrophobic Chitosan Derivatives Bearing Quaternary Ammonium Functionality, Mrunal R. Thatte

LSU Doctoral Dissertations

Chitosan is a naturally occurring, bio-degradable, non-toxic, non-allergenic bio-polysaccharide derived from chitin, found in abundance in nature. Studies aimed at deriving newer applications of chitosan are hence of interest. Among these, one of the focuses of investigations is aimed at excellent antimicrobial activity demonstrated by chitosan. In this context, certain quaternary ammonium derivatives of chitosan have been shown in the past to be highly effective antibacterial materials. In the present study, substituted chitosan derivatives were synthesized and further quaternized using Quat-188 to produce water soluble derivatives at neutral pH. The antibacterial assessments of the quaternized derivatives of substituted chitosan were …

Synthesis Of Montiporynes A And B, Traci Jenelle Speed

Honors Theses

This thesis reports the first complete synthesis of monriporynes A and B. isomeric diacetylenes that bear α, β unsaturated ketone functionalities. Recently isolated from the stony coral Montipora sp. these compounds are reported to possess in vitro cytotoxic activity against several human solid tumor cells. We have synthesized both isomers in three simple steps. In the first step, l-iodononyne was prepared by reacting 1-nonyne with N-iodosuccinimide and a catalytic amount of silver nitrate. This iodoalkyne was then coupled with propargyl alcohol using copper iodide as the catalyst to give 2,4dodecadiynyl alcohol. Finally, the diacetylenic alcohol was subjected to the Swern …

The Synthesis Of Bromoethoxy And Vinylbenzyloxy Substituted Nlo Chromophores, Michael Joseph Matuszewski

Browse all Theses and Dissertations

Multiphoton-absorption processes have recently attracted growing interest because of the potential impact on a wide spectrum of applications, ranging from data storage to photodynamic therapy. From the materials standpoint, particular interest is centered in designing chromophores that exhibit a large two-photon cross-section. The current research is focused on establishing synthetic routes that lead to the formation of derivatives of N,N-diphenyl-(7-benzothiazol-2-yl)-9,9-diethyl-9H-fluoren-2-ylamine which contain meta functionalization. A bromoethoxy functionalized chromophore, N-phenyl-N-(3-(2-bromoethoxy)phenyl)-7-(benzothiazol-2-yl)-9,9-diethyl-9H-fluoren- 2-ylamine , was synthesized and used as a polymer pendent while a vinylbenzyloxy chromophore, N-phenyl-N-(3-(4-vinylbenzyloxy)phenyl)-7- (benzothiazol-2-yl)-9,9-diethyl-9H-fluoren-2-ylamine, was synthesized as a hydrosilation substrate. A compound containing three chromophores, 1,3,5-tris(3-(N-phenyl- 4-(7-(benzothiazol-2-yl)-9,9-diethyl-9H-fluoren-2- ylanilino)phenoxymethyl)benzene, has …

Studies Directed At The Synthesis Of Trialkoxysilyl Substituted Nlo Chromophores, Ida J. Kuhr

Browse all Theses and Dissertations

The synthesis of trialkoxyalkyl substituted NLO chromophores has been investigated. The chromophore 2-(7-(3-hydroxydiphenylamino)-9,9-diethyl-2-fluorenyl)-benzothiazole was prepared by a five step process. Bromination of fluorene yielded 2,7-dibromo-fluorene which could be converted to 2,7-dibromo-9,9-diethylfluorene by alkylation with ethyl iodide in DMSO.Reaction of 2,7-dibromo-9,9-diethylfluorene with one equivalent of butyl lithium followed by reaction with DMF provides 2-bromo-7-formyl-9,9-diethylfluorene. Condensation of 2-bromo-7-formyl-9,9-diethylfluorene and 2-aminobenzenethiol in DMSO results in the formation of 2-(7-bromo-9,9-diethyl-2-fluorenyl)benzothiazole. The conversion of 3-hydroxydiphenylamine to 3-benzyloxy-diphenylamine was accomplished with benzyl bromide and potassium carbonate in DMF. A palladium catalyzed coupling of 3-benzyloxydiphenylamine and 2-(7-bromo-9,9-diethyl-2-fluorenyl)benzothiazole provided 2-(7-(3-hydroxydiphenyl-amino)-9,9-diethyl-2-fluorenyl)benzothiazole. Several attempts to alkylate 2-(7-(3-hydroxydiphenylamino)-9,9-diethyl-2-fluorenyl)benzothiazole with trimethoxysilylmethyl chloride …

Approaches And Methodologies For The Synthesis Of Aromatic Natural Products, Christina A. Goudreau

Honors Theses

Chemists have been captivated by the ability of most natural products to exhibit biological activity which in effect has made them very attractive to pharmaceutical companies. Many over-the-counter drugs such as aspirin were first extracted from natural products and are now an integral part of most of our lives. More importantly, certain drugs such as taxol, which is used to treat breast cancer, initially came from the bark of a yew tree. Extracting these substances from their natural source and using them medicinally at the demand of the consumers would result in the destruction of the natural habitat. Oftentimes, the …

Synthesis And Protection Of Nitrogen Containing Heterocycles, Timothy I. Elwell

Undergraduate Honors Capstone Projects

The pyrrolo[2,3-d] pyrimidine ring systems are present in a variety of antibacterial/anticancer compounds. A scarcity of natural sources has made necessary the need for researchers to find more efficient methodologies to synthesize such compounds.1 The Edstrom research group is currently exploring new routes to these compounds, varying the protecting groups and the precursors used to make them.

Investigation Of New Methods For The Synthesis Of Pyrrolidines And The Generation Of Novel Heterocumulenes, Travis R. Taylor

Undergraduate Honors Capstone Projects

The following paper is a summary of the research completed from March to August of 1990. This research project proceeded through the guidance of Dr. Eric Edstrom incorporating a senior thesis in conjunction with the Honors Program.

New Syntheses Of Diaryl Ethers, Tyrosinols, B-Hydroxytyrosinols, L,L-Isodityrosinol And L,L-Isodityrosine-Derived Agents Via The Diels-Alder Reaction, Xianqi Feng

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Syntheses of diaryl ethers were approached by use of a Diels-Alder reaction employing a new type of diene attached with an aryloxy group. Thus, 2-methyl-3-phenoxybutadiene (90b ), 2- methoxy-3-phenoxybutadiene (92b) and (4S)-3-(t- butyloxycarbony1)-2 ,2-dimethyl-4-( 4-(3-methoxy-1,3 -butadienyl-2- oxy )phenylmethyl]oxazolidine (93b) were synthesized in ~65% yields by methylenation of the carbonyl function in the corresponding 2- substituted acrylate aryl ester using Tebbe's reagent. The 1,3- bis[(trimethylsilyl)oxy ]-2-phenoxybutadiene (105) was made from 1-phenoxy-2-propanone (101) by a sequence of formylation and enolsilylation. Methyl propiolate (107) and dimethyl acetylenedicarboxylate (113) were heated at reflux with diene 9 0 b and 92b in toluene to provide …

1-Acyldihydropyridones As Synthetic Intermediates, Michael Andrew Foley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The most efficient and stereoselective total synthesis of (+/-)- lausbine II to date has been achieved. The key steps in this are the copper-mediated conjugate addition reaction of the Grignard reagent of 1-bromo-4-chlorobutane to a dihydropyridone and a stereoselective reduction of a quinolizidinone.

Methodology has been developed for the convenient synthesis of 1-acyl-2-substituted-1,2,5,6-tetrahydropyridines. This was accomplished by adding novel alkylzinc iodides to the 1-acyliminium ion derived from N-phenoxycarbonyl-4-methoxy-1,2,3,4-tetrahydropyridine.

Studies In Peptide Synthesis Towards The Lanthionine Analog Of Des-N-Tetramethyl Triostin A, Ganesh Devdas Kini

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies have been carried out towards the synthesis of bicyclic octadidepsipeptide lanthionine 4, an analog of des-N-tetramethyl triostin A. Starting with a symmetrical lanthionine unit 5 (R₁, R₃ = Me; R₂, R₄ = t-butyloxycarbonyl), synthesized from the corresponding cystine by contraction with hexaethylphosphorus triamide, linear octadidepsipeptides 29 and 32 were synthesized.

Attempted cyclizations of 29 and 32 to the bicyclic octapeptide were unsuccessful.

The failure of the symmetrical approach to 4 prompted the synthesis of an unsymmetrical lanthionine unit with appropriate compatible protecting groups. Attempts to synthesize unsymmetrical lanthionines by nucleophilic displacement on …

Studies Toward The Synthesis Of A- And B- Mercapto Alanine Derivatives, And Of A,B- And B, B- Dimercapto Alanine Derivatives, Aldean James Kolar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A convenient, economical, large scale synthesis of N-acetyldehydro-alanine (a-acetamidoacrylic acid) and its methyl ester was developed via a sequence of N-chlorination-dehydrochlorination. The method was extended to the synthesis of the corresponding N-benzoyl, N-phenylacetyl and N-benzyloxycarbonyl derivatives.

The conversion of a-methoxy-N-acetyl alanine derivatives to the corresponding a-mercapto alanine derivatives, using zinc chloride and an appropriate mercaptan, was investigated. Methyl a-methoxy-N-acetyl-D, L-alaninate was successfully converted to the a-acetylthio derivative, in 24% yield; however, a 90% yield could be obtained by treatment of the dehydroalanine derivative with hydrogen chloride gas in neat thiolacetic acid.

A facile conversion of the a-acetylthio derivative to the …

Mechanism Of Phenyl Azide-1,2-Cyclonoadiene Adduct Formation And Isomerization Of This Adduct, Isom Harrison

University of the Pacific Theses and Dissertations

A major purpose of this research was to investigate the mechanism of aryl azide addition to allenes. Much evidence has accumulated in support of a concerted mechanism for aryl azide additions to simple alkenes. Consistent with these findings, this addition is a symmetry allowed process. The analagous aryl azide additions to allenes have received little mechanistic study. The approach taken in this work was to probe the mechanism by using optically active 1,2-cyclonanadiene, observing the stereochemistry of the adduct formed upon addition of phenyl azide.

Another goal was to investigate the isomerization of the phenyl azide-1,2-cylononadiene adduct, 10-phenyl-10,11,12-triaza-△ 11 -bicyclo …

The Synthetic Chemistry Of Carboxyalkyl-P, P-Diphenyl Phosphines, Larry S. Andrews

Chemistry Honors Papers

This 55 page thesis examines the preparation of carboxyalkyl-P and P-diphenyl phosphines to determine their acidity characteristics as a function of structure and to characterize their ability to function as chelating agents.