Organic Chemistry Commons^™

Silicon And Tin Substituted Halocyclopropanes: Approaches To New Carbenes And Strained Cyclic Allenes, Noura Srour

Honors Theses

Chloro(trimethylsilyl)carbene and chloro(trimethylstannyl)carbene were generated through photolysis of cyclopropanated phenanthrene precursors which were synthesized in two steps. The photolysis reactions were done in the presence of cis and/or trans-beta-methylstyrene. Though product peaks corresponding to the carbene-alkene adducts were observed in the GCMS, the yields were too low for their isolation and complete characterization. Density functional theory (DFT) calculations were performed on the stereoisomers of the precursor to Chloro(trimethylsilyl)carbene and the carbene itself. Surprisingly, Chloro(trimethylsilyl)carbene’s triplet state was found to be more stable than the singlet at this level of theory.

In a related project, (1-bromo-1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)trimethylstannane, was …

Harnessing Radical Reactivity For The Construction Of Natural Product Frameworks And Transition Metal Catalyst Stability In A Modified Kochi Coupling Reaction, Mathes Hewage Hansamali Sakuntala Sirinimal

Wayne State University Dissertations

Polycyclic N-containing heterocycles play an important role in therapeutic

applications and as molecular tools in studying biological processes, making them

important synthetic targets. Current synthetic approaches are too lengthy, use toxic

reagents or are limited to accessing a particular framework and hence, their synthesis

warrant further study. We have recently developed conditions to avoid both reduction and

slow addition in aminyl radical cyclizations in our venture to access the constrained ABC

core of calyciphilline A, a Daphniphyllum alkaloid. An electron deficient enone with a

pendent internal alkyne as the neutral aminyl radical precursor was used for radical

cyclization. Based on …

Surface Oxygenation Of Biochar Through Ozonization For Dramatically Enhancing Cation Exchange Capacity, Matthew D. Huff, Sarah Marshall, Haitham A. Saeed, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

Background

Biochar cation exchange capacity (CEC) is a key property that is central to biochar environmental applications including the retention of soil nutrients in soil amendment and removal of certain pollutants in water-filtration applications.

Results

This study reports an innovative biochar-ozonization process that dramatically increases the CEC value of biochars by a factor of 2. The ozonized biochars also show great improvement on adsorption of methylene blue by as much as a factor of about 5. In this study, biochar samples treated with and without ozone were analyzed by means of pH and CEC assays, water field capacity measurement, elemental …

Detection And Determination Of Food Residues In Native American Pottery, Katherine A. Plotzke

Honors Program Theses

The purpose of this research was to develop a new method of analyzing organic residues left on Native American pottery using linear Raman spectroscopy. Native American pottery was replicated using terra cotta and maple syrup was boiled in each of the pots using boiling stones. The pottery shards were then analyzed using Raman spectroscopy. Shards of pottery with maple syrup residue were compared to the standards and the syrup residue was not only detected, but also matched to compounds in the instrument library. Typically, the study of Native American pottery has been done in a variety of different ways, many …

Cascade Annulation And Ring-Opening Reactions Of Castagnoli-Cushman-Derived Allylic And Benzylic Thiomorpholinonates, Abdikani Omar Farah

All Master's Theses

Sulfur-containing compounds are prevalent in antibiotics, essential amino acids, bacterial RNA, food flavors, and enzymes. The divalent sulfur atom introduces a metabolic liability from a drug discovery standpoint. Indeed, it is quite telling that all the top ten best-selling drugs in 2012 contained sulfur. In this context, there is a growing need for the synthesis of sulfur-containing compounds in ways that are practical and cost-effective. One approach taken to achieve this goal is to employ diversity-oriented synthesis (DOS), which produces diverse complex molecules with similar core structures from a common precursor. When a DOS features a cascade or domino reaction …

Effect Of Curing Rate On The Microstructure And Macroscopic Properties Of Epoxy Fiberglass Composites, Ammar Patel, Olesksandr Kravchenko, Ica Manas-Zloczower

Mechanical & Aerospace Engineering Faculty Publications

Curing rates of an epoxy amine system were varied via different curing cycles, and glass-fiber epoxy composites were prepared using the same protocol, with the aim of investigating the correlation between microstructure and composite properties. It was found that the fast curing cycle resulted in a non-homogenous network, with a larger percentage of a softer phase. Homogenized composite properties, namely storage modulus and quasi-static intra-laminar shear strength, remained unaffected by the change in resin microstructure. However, fatigue tests revealed a significant reduction in fatigue life for composites cured at fast curing rates, while composites with curing cycles that allowed a …

Syntheses Of Azepinoindole Alkaloids Cimitrypazepine, Fargesine And Hyrtioreticulins C & D, Ganesh Ghimire

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Watanabe-Cenini-Söderberg reductive N-heterocyclization has emerged as a powerful tool for the synthesis of a variety of functionalized indoles. Söderberg’s elaboration of this methodology has been utilized as a late-stage cyclization protocol for the synthesis of azepinoindole alkaloids, a class of natural products characterized by an azepane skeleton fused with an indole ring. Short syntheses of the naturally occurring azepino[5,4,3-cd]indole alkaloids, cimitrypazepine, fargesine, and the diastereomeric hyrtioreticulins C & D have been completed starting from commercially available tetra-substituted benzene derivatives. The key azepinoindole core in each case was assembled via an intramolecular Mizoroki-Heck reaction followed by a …

Nickel-Catalyzed Oxidative Decarboxylative (Hetero)Arylation Reactions, Aaron P. Honeycutt

Graduate Theses, Dissertations, and Problem Reports (ETD)

Transition-metal-catalyzed decarboxylative coupling reactions have gained considerable attention over the past decade as an efficient route to form heterobiaryls. However, current methods for oxidative decarboxylative (hetero)arylation with unactivated C-H bonds have been limited by poor substrate scope, control of regioselectivity, and chemospecificity. This thesis describes the development of a new nickel-catalyzed oxidative decarboxylative coupling (ODC) with unactivated C-H bonds. The first chapter discusses the development of the new nickel-catalyzed ODC reaction to enable the coupling of a N,N'-bidentate directing group with a broad scope of heteroaromatic carboxylates and ortho-substituted benzoates, a scope that has not been achieved in previous …

Synthesis Of New Bodipy Analogs, John Dilyard

Williams Honors College, Honors Research Projects

This report examines the synthesis of new ligands based upon dipyrazolylmethane and diindazolylmethane. The goal of these modifications is to increase the acidity of the proton on the methyl carbon to allow for deprotonation. The ligands synthesized were dipyrazolylphenylmethane and diindazolylphenylmethane, as well as modifications of the latter. The products were analyzed by NMR spectroscopy and one crystal structure was obtained of diindazolylphenylmethane.

Determination Of Atrazine Concentration In Freshwaters Using Fluorescence Spectroscopy, Boniface Osei Amankona

Online Theses and Dissertations

Atrazine is the most widely used herbicides in USA, but its negative impact on aquatic ecosystem cannot be over-looked. Atrazine was traditionally determined through liquid/gas chromatography or IR spectroscopy. However, these methods are either time-consuming or costly, so fluorescence spectroscopy is investigated as a more cost and time efficient alternative. Literature value of the optimal wavelength of atrazine was found to be 350 nm emission. Experimental value for emission scanned of atrazine resulted in an optimal wavelength of 363 nm. Known and unknown concentrations of atrazine will be analyzed using fluorescence spectrophotometer to develop a calibration curve.

The calibration concentration …

Metabolomic Analysis Of The Urine And Tissue In Rats Prone To Type 1 Diabetes Using Nmr, Emily Hunt, Bobba Sumedha, James Wolfsberger

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Measuring Islet Sensitivity To Glucose Stimuulated Insulin Secretion In Lew.1wr1 Rat, Helen Gibson

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

The Huntingtin Protein: Organic Synthesis Of Poly(Glutamine) Through Side Chain Modification Of Poly(Glutamic Acid), Allana Schafer

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Synthesis And Characterization Of Glycolipids, Glycoclusters And Glycomacrocycles, Anji Chen

Chemistry & Biochemistry Theses & Dissertations

Low molecular-weight gelators (LMWGs) are a fascinating and interesting class of compounds that can self-assemble and form supramolecular structures in appropriate solvents. The gelators form fibrous networks which entrap the solvent and result in a supramolecular gel. Carbohydrate-derived LMWGs are especially useful since they are more likely to be biocompatible and biodegradable. Dendritic gelators are branch-shaped molecules with precise molecular weight that are between small molecules and polymer gelators. Glycoclusters with sugar moieties at the periphery of the molecules are important classes of bioactive compounds due to the multivalency effect. Lower generation glycoclusters are relatively small branched systems that have …

The Investigation Of Oxidative Addition Reactions Of Metal Complexes In Cross-Coupling Catalytic Cycles Based On A Unique Methodology Of Coupled Ion/Ion-Ion/Molecule Reactions, Mariah L. Parker

Theses and Dissertations

Popular catalytic cycles, such as the Heck, Suzuki, and Negishi, utilize metal centers that oscillate between two oxidation states (II/0) during the three main steps of catalysis: reductive elimination, oxidative addition, and transmetallation. There has been a push to use less toxic, cheaper metal centers in catalytic cycles, leading to interest in first-row transition metals, such as nickel and cobalt. With these metals, the cycles can potentially pass through the +1 oxidation state, which acts as reactive intermediates, undergoing oxidative additions to form products, potentially with radical characteristics. The oxidative addition steps of catalytic cycles are critical to determining overall …

Gas-Phase Studies Of Nucleophilic Substitution Reactions: Halogenating And Dehalogenating Aromatic Heterocycles, Leah L. Donham

Theses and Dissertations

Halogenated heterocycles are common in pharmaceutical and natural products and there is a need to develop a better understanding of processes used to synthesize them. Although the halogenation of simple aromatic molecules is well understood, the mechanisms behind the halogenation of aromatic heterocycles have been more problematic to elucidate because multiple pathways are possible. Recently, new, radical-based mechanisms have been proposed for heterocycle halogenation. In this study, we examine and test the viability of possible nucleophilic substitution, S_N2@X, mechanisms in the halogenation of anions derived from the deprotonation of aromatic heterocycles. All the experiments were done in a …

Oxidation Of Β-O-4 Lignin Model Compounds And Application To Lignin Linkage Degradation Facilitated By Mechanochemical Treatment And Two-Step Oxidative Depolymerization, Soledad G. Yao

Theses and Dissertations--Chemistry

The oxidation of lignin model compounds was studied in conventional solvents in parallel with oxidations in ionic liquid solvents. Catalyst systems were investigated in ionic liquid solvents to determine how reaction rates and the selectivity for benzylic carbon oxidation were affected. Oxidation rates were often lower in ionic liquids than in conventional solvents ‒ as indicated by lower conversion in a standard reaction time ‒ likely due, at least in part, to the higher viscosity of ionic liquids. Mechano chemical treatment of Indulin AT kraft lignin by ball milling with KOH and toluene produced significant carbonyl functionality, among other changes. …

Study Of The Effect Of Steric Bulk Of Side Chains On The Properties Of Conjugated Polymers, Bei Zhang

Theses and Dissertations--Chemistry

Donor-acceptor conjugated polymers opened a new era for conjugated polymer research due to the abundant selection and combination of different conjugated units. This class of polymers function as semiconductor materials with potential application in plastic consumer electronics. The frontier molecular orbital energies of the polymers are generally determined by the selection of donor and acceptor units in the backbone structure, and their substituents. The side chains attached to the backbone not only affect the solubility of the materials, but also their self-assembly and morphological characteristics, which indirectly govern optoelectronic properties. It is important therefore to consider backbone architectures and the …

Catalytic Conversion Of Monosaccharides Into 5-(Hydroxymethyl)Furfural In Ionic Liquids Using Aluminum Complexes Bearing Bidentate (Aminomethyl)Phenolate Ligands, Daudi Sayialel Saang'onyo

Theses and Dissertations--Chemistry

Currently, the major sources of fuel, energy, and chemicals are nonrenewable fossil resources such as petroleum, natural gas, and coal. Additionally, petroleum is used for the production of most transportation fuels and for the production of about 95% of organic chemicals. However, the production and use of non-renewable fossil fuels are unsustainable. For economic and environmental sustainability, there is a need to search for new and/or renewable resources and technologies for energy, fuels, and chemicals production that have the potential of effectively substituting fossil resources. In this context, lignocellulosic biomass is one of the candidates that meet these requirements due …

Design And Synthesis Of Functional Organic Materials, Anthony Joseph Petty Ii

Theses and Dissertations--Chemistry

Control of solid state ordering in conjugated small molecules is paramount to the continued development and implementation of organic materials in electronic devices. However, there exists no reliable method on which to predicatively determine how a change to the molecular structure will impact the solid-state packing. As such, the molecule must be synthesized before its solid-state packing can be definitively evaluated. However, once the packing structure of a material is known there exist both qualitative structure- function relationships derived from the literature, as well as quantitative computational methods that can be employed to suggest if a material will perform well …