Organic Chemistry Commons^™

Arylation Of Nitrogen, Oxygen And Carbon Nucleophiles By Aryl(Tmp)Iodonium Salts, Joseph Jordan Hatton

Dissertations and Theses

Substituted aromatic rings are present in industry in a plethora of organic molecules such as pharmaceuticals, agrochemicals, materials and beyond. Therefore, methods for broadly installing aryl rings into other compounds to create substituted aromatic rings are valuable to many organic chemists. Historically these transformations are achieved through methods such as nucleophilic aromatic substitution and metal catalyzed cross-coupling. Nucleophilic aromatic substitution is a user-friendly method in this space but is limited by reliance on specific electronics. Metal catalyzed cross-coupling reduced the dependence on electronics in this space, but metals are generally unattractive reagents due to high costs, toxicity and challenges with …

Enabling New Synthetic Platforms For Aryne Synthesis With Aryl Thianthrenium Reagents, Riley Augustus Roberts

Dissertations and Theses

The enormous importance of aromatic rings in organic molecules cannot be understated. Aromatic rings are present in the majority of pharmaceuticals, agrochemicals, and consumer products. The way in which these rings are arranged and substituted results in a molecule’s unique properties. Because of this, the current limitations of the chemical methods used to synthesize these molecules results in limited structural diversity and thus missed opportunities for the development of value-added products. To this end, this work demonstrates novel methods of aryne synthesis, aryl thianthrenium synthesis and a unique approach to structural scaffold hopping. The approaches presented herein allow for rapid …

Efficient And Chemoselective Access To Highly Functionalized Arenes By C-H Deprotonative Generation Of Aryne Intermediates, Bryan Edward Metze

Dissertations and Theses

Arenes are a ubiquitous structural motif occurring in numerous organic pharmaceuticals, agrochemicals, secondary metabolites, and functional materials. As such, studies on the characterization, functionalization, and properties of arenes have been a central pillar of organic chemistry since its inception. Early methods to synthesize complex benzenoid rings focused on ring functionalization rather than ring construction due to the high accessibility of very simple arenes and the wide range of aromatic substitution reactions discovered in the late 19th century. As the importance of arenes was recognized more methods of building complex arenes emerged. Both classical and modern approaches are still somewhat limited, …

Synthesis Of Novel 5-Aryl 2’-Deoxyuridine And 2’-Deoxycytidine Analogues, Kevin E. Persaud

Dissertations and Theses

Briefly, the following report details a synthetic route to prepare 5-phenyl-2’-deoxycytidine analogues. This multistep synthesis began with silyl protection of the 3’- and 5’-hydroxyl groups of 5-iodo-2’-deoxyuridine. Next, the installation of a phenyl ring at the C5 position of the nucleobase via a Suzuki-Miyaura cross-coupling reaction, yielding 5-phenyl-2’-deoxyuridine (5-PdU). After that, modification of the obtained 5-PdU at the C4 position was performed with benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP, a peptide-coupling agent) and a base (cesium carbonate) to activate the amide group of the uridine nucleobase for subsequent displacement with a variety of amines. Modification of the C4 position resulted in protected 5-phenyl-2’-deoxycytidine …

Designing Fluorescent Moscs For Potential Applications In Illicit Drugs Detection, Robyn Nicole Cook

Dissertations and Theses

Illicit and hazardous substances pose a serious effect on the human body which can create longer-term issues on the mental and physical health which potentially lead to fatalities. Current methods for detecting illicit substances include analytical techniques like mass spectrometry (MS) and gas/liquid chromatography (GC/LC) which are known for accuracy and sensitivity. However, these instruments are bulky, costly, time-consuming, and require highly trained personnel. An alternative approach to overcoming these limitations is to employ nanostructured molecule-based chemical sensing technologies that are user-friendly, portable, and cost-effective with the sensitivity for detecting illicit substances. One such candidate is metal-organic super-containers (MOSCs), which …

Studies On Bonding, Syntheses, And Applications Of Diarylhalonium Compounds, Shubhendu Karandikar

Dissertations and Theses

Organic compounds containing functionalized benzenoid rings have found tremendous applications in pharmaceuticals, agrochemicals, commodity chemicals, and beyond. As a result, development of methods for the synthesis of functionalized benzenoid rings has gained much attention from the synthetic community. Although many transition-metal mediated methods to functionalize benzenoid rings are known, there has been an upsurge of activity in developing protocols for decoration of benzenoid cores promoted by p-block elements. This excitement stems from the sustainability of earth-abundant elements and unique reactivity patterns observed within the p-block. Among these, transformations promoted by hypervalent halogen compounds, and especially, the diarylhalonium salts are very …

Structural And Functional Modulation Of Metal-Organic Supercontainers (Moscs) And Their Applications In Supramolecular Catalysis, Shrijana Dc

Dissertations and Theses

Metal-organic supercontainers (MOSCs), a breakthrough development in our laboratory since 2012, have emerged as promising enzyme mimics, showcasing their prowess in encapsulating guest molecules and catalyzing confined chemical reactions. The intrigue surrounding MOSCs stems from their extraordinary traits, encompassing multiple binding domains, high stability, large surface area, tunable pore size, and structural modularity. Primarily comprising sulfonylcalix[4]arenes, divalent metal ions, and carboxylate linkers, MOSCs' quintessential architecture comprises both endo- and exo- nano-cavities, amenable to guest interaction, with geometry and functionality manipulation achievable through precise precursor selection. Nonetheless, early MOSC models exhibit limited reactivity, often necessitating more potent nucleophiles or electrophiles. This …

Synthesis Of Diaryl And Alkyl-Aryl Ethers Via Diaryl Iodonium Reagents, Rory Tennessee Gallagher

Dissertations and Theses

Substituted benzenoid rings are a prevalent motif in many industries including high tech, agrochemicals, and pharmaceuticals. As a result, the arylation of chemical compounds is a highly sought-after chemical transformation. There are many literature methods to achieve this chemical transformation, nucleophilic aromatic substitution and transition metal catalysis are both widely used and studied. Diaryliodonium salt mediated chemistry is an attractive alternative to these methods as it does not require the expensive toxic metals and designer ligands of transition metal catalysis and is not restricted to electron deficient aryl rings with specific substitution patterns like nucleophilic aromatic substitution.

Many diaryliodonium salt …

Speciation Of Diaryliodonium Salts In Solution And Their Reactivity Towards N-Nucleophiles (Phthalimide And Amines) And O-Nucleophiles (Phenols And Phenoxide), Souradeep Basu

Dissertations and Theses

Benzenoid rings are prevalent in pharmaceutical drug molecules, agrochemical molecules and even in some polymers used in electronic device. Aryl rings are often installed using metal catalysis, however, metal free arylations are known but limited. Diaryliodonium salts are novel electrophilic arylating agents. Herein, metal free N-arylation of phthalimide and diarylether formation using aryl(TMP)iodonium salts is described.

The structure of diaryliodonium salts has been primarily studied in either the solid state or in-silico. The structure and speciation of diaryliodonium salts in solution is not well explored. In this work evidence of dimer formation of aryl(Mes)iodonium salts in chloroform using …

Poly(Β-Gal-Thr): A New Scalable Synthetic Mucin, Manuel A. Lema

Dissertations and Theses

A method for the preparation of glycosylated polypeptides via the nucleophilic ring-opening polymerization of a glycosylated N-carboxyanhydride (NCA) monomer is reported. The synthesis of 2,3,4,6-tetraacetyl-β-galactose-threonine N-carboxyanhydride (β-AcO-Gal-Thr-NCA) monomer in 5 steps with an 8 % overall yield is described, and the single-crystal X-ray structure is provided. The effect of a series of Ni⁰-based organometallic initiators, nucleophilic amine initiators, co-catalysts, and solvents on the polymerization were explored. The kinetics of the three most promising conditions were studied in greater detail. The conditions that provided the highest yield, low polydispersity (Ð), and …

Designing Environmentally Responsible And Highly Effective Bioorthogonally Functionalized Chiral Mri Contrast Agents, Karley Breann Maier

Dissertations and Theses

Magnetic resonance imaging (MRI) revolutionized diagnostic imaging and modernized the characterization of numerous diseases. The clinical success of MRI is in large part due to the employment of gadolinium-based contrast agents (GBCAs). Due to sensitivity limitations, GBCAs are indicated at markedly high dosages (~1 g Gd³⁺ per exam). The routine use of such large quantities of gadolinium poses significant health and environmental risks. There are growing concerns over the effects of dechelation of the metal in vivo and the possible effect of resulting gadolinium deposition. Concurrently, there is a rising awareness of gadolinium anomalies borne by GBCAs which undergo …

Selenium Probes For The Detection Of Thioredoxin Reductase Activity, Tendai Joseph Mafireyi

Dissertations and Theses

The identification and quantification of proteins and enzymatic activity in living tissues frequently requires the use of invasive procedures such as biopsy. These techniques can inhibit measurements of protein levels in real-time, and the disruption of tissue can lead to the loss of important information concerning the spatial distribution and differential activities in various cell types. The use of small organic fluorescent probes that rely on activation or accumulation within a tissue embody robust methods of detection that address these issues. This dissertation describes the design, synthesis and evaluation of fluorescent probes that can detect the enzyme thioredoxin reductase (TrxR). …

Aryne-Guided C-H Functionalization Of Benzenoid Rings Using Diaryliodonium Salts, Aleksandra Nilova

Dissertations and Theses

The benzenoid core is a frequent and irreplaceable component of biologically active molecules. Structure function relationship of these compounds has been broadly analyzed and presented in numerous literature reports. Herein, we augmented existing knowledge by a broad analysis of the benzenoid substitution patterns in small molecule active pharmaceutical ingredients approved by the FDA. Our findings reveal a strong correlation that the most represented substitution patterns are those achieved via S_EAr. Despite the rapid development of methods to functionalize benzenoid rings, the lack of synthetic methodologies to access sterically and electronically unfavorable positions is highlighted. We sought to establish …

Sugar-Derived Oleogels In Cosmetics And Food Applications: A Case Study Of Trehalose- And Mannitol-Based Gelators, Polina Tsupko

Dissertations and Theses

Gels represent an indispensable part of our everyday lives with direct applications in food, medicine, cosmetics and other industries. Amphiphilic molecules have been shown to act as low molecular weight gelators (LMWGs) and are becoming the main focus of several research groups. Their ability to self-assemble into various morphologies from micelles to bilayer sheets, and remain stable due to noncovalent forces responsible for the formation of the 3D network—Self-Assembled Fibrillar Network (SAFiNs)—is in the core of their ability to produce molecular gels. Those amphiphilic molecules capable of adsorbing at the interface and behaving as surface active agents are known as …

Reductions By Cobalt-Catalyzed Production Of Hydrogen Gas From Nabh4 In A Two-Chamber System, Joshua K. Mitchell

Dissertations and Theses

The work outlined in this thesis describes a bench-scale methodology involving a two-chamber system for conducting catalytic hydrogenation reactions by obtaining hydrogen (H₂) gas from stable sodium borohydride (NaBH₄). Whereas NaBH₄ is widely used for a variety of reductions and is known to produce H₂ gas in protic media, to our knowledge, there has been scant use of NaBH₄ in catalytic hydrogenation chemistry where it has been used as a source of H₂ gas. In this work, addition of a catalytic amount of CoCl₂•6H₂O as an aqueous solution …

Copper-Mediated N1-Arylation Of Benzotriazoles, Magdalena R. Andrzejewska

Dissertations and Theses

Benzotriazoles are group of bicyclic heterocyclic compounds that contain three nitrogen atoms fused to a benzene ring. Along with their derivatives, they possess a wide range of properties. They are used in medical field, as they exhibit such properties as antibacterial,antiplasmoidal,antiprotozoal, antifungal and anti-inflammatory activities, among others. They are also used in various industries as herbicides, UV absorbers, deicing and antiicing agents and corrosion inhibitors, to list a few. Because of their wide range of applications, we designed a new two-step synthesis for the formation of N-1-aryl benzotriazoles. 1-Hydroxy-1H-benzotriazole N-oxides were synthesized using phenylboronic acid (PhB(OH) …

The Discovery And Development Of Metal-Free Arylation Reactions With Unsymmetrical Diaryliodonium Salts, Sunil Kumar Sundalam

Dissertations and Theses

Functionalizing arenes and heteroarenes has been an active area of research since the 19th century, due to the presence of these molecular structures in many industrially important sectors. A tremendous amount of research has been published in achieving these chemical transformations using stoichiometric reagents and transition metal-catalyzed reactions. However, challenges still remain. An alternative and comparable methodology to metal-catalyzed reactions to overcome the drawbacks will advance this particular area of research is desirable.

Hypervalent iodine compounds offer a promising approach to metal-free arylation reactions. These mild, air and moisture stable compounds have showed significant success as non-toxic and metal-free reagents …

Adsorption Of Antibiotics By Vermiculite, Mosa J. Ferdous

Dissertations and Theses

The occurrence of residual antibiotics in the environment has been a worldwide issue and warrants the development of inexpensive yet effective methods for antibiotics removal from contaminated water. In this thesis work, the adsorption of four antibiotics, namely chlorotetracycline (CTC), oxytetracycline (OTC), ofloxacin (OFL), and enrofloxacin (ENR), onto natural vermiculite has been studied using batch (static) and column (dynamic) adsorption techniques. The Langmuir and Freundlich isotherm models were initially used to explain the adsorption processes. The separation factor (RL) values derived from the Langmuir model and the 1/n values derived from Freundlich model in the present investigation were less than …

Characterization, Dna Binding And Cleavage Activities Of New Prodigiosin And Tambjamine Analogues And Their Cu²⁺ And Zn²⁺ Complexes, Karen Chichetu

Dissertations and Theses

Prodigiosins and tambjamines are natural compounds from bacterial and marine sources belonging to a family containing a common 4-methoxy-2,2'-bipyrrole core. These compounds have received a lot of interest due to their promising biological activities. Studies have suggested DNA as a potential therapeutic target for the natural prodigiosin and tambjamine due to their ability to facilitate oxidative DNA cleavage in the presence of Cu²⁺. Based on this we sought to study the metal binding activity of new prodigiosin and tambjamine analogues. A new prodigiosin analogue was synthesized and complexed with Cu²⁺. This revealed 1:1 complex formation between …

Transport Of Ozone Across An Air/Water Interface Coupled With Aqueous Decomposition, Ahmad Ali Mehrabzadeh

Dissertations and Theses

Photoacoustic spectroscopy was used to analyze the transport of ozone through the air/water interface. Experimental results showed that the ozone transport rate is similar to rates measured for other gases of low solubility and low reactivity. The transport rate increases with increasing pH. The decomposition rate of ozone was studied in solutions. The decomposition rate also depends on the pH of the solution, and in high pHs both the deposition velocity and the decomposition rate constant of ozone have larger values. The value of the deposition velocity (Kd) is 3.7 ± .9 x 10^-3 cm/sec and the decomposition rate …

A Study Of The Photolysis Of O-Methyl Podocarpinitrile Oxide, Dianne Marie Hunter

Dissertations and Theses

The photolytic reaction of 0-methyl podocarpinitrile oxide to yield the δ-lactam (shown below) was studied under various conditions such as: solvent (hexane, methanol), mercury lamp wattage (lOOW, 450W), filter (Pyrex, Corex, Vycor), and additives (dichloromethane, hexafluorobenzene). The reactions were analyzed with IR, NMR and HPLC. Preparative medium pressure liquid chromatography and TLC were used in the δ-lactam isolation. The conditions resulting in the optimum yield of δ-lactam were determined. The photolytic stability of the δ-lactam under the conditions in which it was formed indicated that it was relatively stable only in hexane.

The Concentration And Speciation Of Sugars In Natural Waters, Minoo Shakerin Sweet

Dissertations and Theses

Due to the importance of carbohydrates in biological systems, many efforts have been made to develop a quantitative method for analysis of carbohydrates in natural waters. The low concentrations of dissolved sugars in natural waters require a sensitive analytical method. In this study, gas chromatography of alditol acetate derivatives of sugars was investigated for quantitative and qualitative analysis of individual dissolved sugars in natural waters. The alditol acetate derivatives of sugars give only one derivative for each sugar, yielding qualitative and quantitative results.

The detection limit was 25 nM for each sugar. Because of this very low detection limit, only …

Catechol Effected Dissolution Of Silicate Minerals, James Maurice Kelley

Dissertations and Theses

The chemical properties of guanidinium tris(catecholato)siliconate, [(H₂N)₂C=NH₂]₂[Si(C₆H₄O₂)₃]·XH₂O (0 < X < 1), precipitated from an ammoniacal solution of silica and catechol by adding guanidinium hydrochloride, (H₂N)₂C=NH·HC1, were studied, and infrared, nmr, x-ray powder diffraction, and analytical data were gathered.

This same compound was, upon addition of' (H₂N)₂C=NH·HC1, isolated from 0.25, M aqueous catechol solutions buffered at pH 10 and containing the silicate minerals albite, andradite, muscovite, pyrophyllite, talc, and wollastonite, and also from unbuffered catechol solutions containing wollastonite and andradite.

It is concluded from this work that the formation of an anionic catechol-silicon complex, Si(C₆H₄O₂)₃²⁻, is largely responsible for the dissolution of the minerals mentioned above. From this conclusion, it is proposed that naturally occurring members of the class of organic compounds to which catechol belongs, the aromatic v̲i̲̲c̲-diols, may play …