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- Boracarboxylation (3)
- 1 (2)
- Benzannulation (2)
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- Cyclotrimerization (2)
- Decarboxylation (2)
- Fragmentation (2)
- Photocatalysis (2)
- 6-diynes (1)
- 6-enynes (1)
- Aerobic oxidation (1)
- Alkene (1)
- Alkyl fluorides. (1)
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- Amine Alkylation Reaction (1)
- Benzimidazoles (1)
- Benzoxazoles (1)
- Bis-nucleophiles (1)
- Bora-ibuprofen (1)
- Borafluorolactonate (1)
- Boron (1)
- Boronic Acid (1)
- C-H activation (1)
- Cannabinoid type 2 receptor (1)
- Cimitrypazepine (1)
- Cobalt (1)
- Cobalt complexes (1)
- Cooperative heating (1)
- Coupling Reactions (1)
Articles 1 - 22 of 22
Full-Text Articles in Chemistry
Photoinduced Alpha-Hydroxy C–H Alkylation Of Mono-Alcohols Via Hydrogen Atom Transfer (Hat) Of An Activated Boron-Containing Complex, Courtney Deanna Glenn
Photoinduced Alpha-Hydroxy C–H Alkylation Of Mono-Alcohols Via Hydrogen Atom Transfer (Hat) Of An Activated Boron-Containing Complex, Courtney Deanna Glenn
Graduate Theses, Dissertations, and Problem Reports
Hydroxy (-OH) groups are one of the most abundant functional groups found in natural products and pharmaceuticals with many of these compounds containing multiple alcohol classes. The ability to selectively functionalize a specific α-OH C–H bond in the presence of other competitive sites would provide straightforward access to new, potentially bioactive compounds. In recent literature, photoredox catalysis has been implemented to perform site and stereoselective α-OH C–H functionalization of cis-diol containing substrates. Incorporating an organoboron cocatalyst into these systems have proven to be crucial in decreasing the bond dissociation energy (BDE) and increasing hydricity of the α-OH C–H bond …
C–H Alkylation Of Diol Substrates Using Bifunctional Boronic Acid Catalysts, Matthew Ryan Ross
C–H Alkylation Of Diol Substrates Using Bifunctional Boronic Acid Catalysts, Matthew Ryan Ross
Graduate Theses, Dissertations, and Problem Reports
Boronic acid catalysts in combination with a Lewis base have been used in previous work to perform site-selective C–H alkylation reactions targeting the α-hydroxy C–H bond of diols through a photoredox activated hydrogen atom transfer. This is done by accessing a tetracoordinate boronic acid – Lewis base complex which then mediates the hydrogen atom transfer. The research hypothesizes that combining the boronic acid and Lewis base into one molecule not only simplifies the reaction but also has the potential to unlock C–H alkylation sites previously inaccessible. This is plausible because the Lewis base portion of the synthesized bifunctional boronic acid …
Investigation Of Deoxyfluorination Of Alkyl Alcohols Using Pentafluoropyridines Through A Covalent Intermediate, Christopher Allen Bias
Investigation Of Deoxyfluorination Of Alkyl Alcohols Using Pentafluoropyridines Through A Covalent Intermediate, Christopher Allen Bias
Graduate Theses, Dissertations, and Problem Reports
Organofluorines are an omnipresent class of organic molecules, especially in pharmaceuticals. Selective fluorination of drug molecules allows for the influence of properties including metabolic activity, solubility, and intrinsic potency. Deoxyfluorinations are typically performed via generation of nucleophilic fluoride from a deoxyfluorination agent. Traditionally, diethylaminosulfur trifluoride (DAST) is the reagent of choice for these reactions, and it remains a popular reagent today. However, it has a propensity to form elimination side products and explode. Several research groups have recently developed new classes of deoxyfluorination agents including imidazole-based reagents (PhenoFluor) and sulfonyl fluorides (PyFluor) that exhibit better functional group tolerance and much …
Copper-Catalyzed Dehydrogenative Decarboxylation Reactions Of Carboxylic Acids To Alkenes, Michael P. Stanton
Copper-Catalyzed Dehydrogenative Decarboxylation Reactions Of Carboxylic Acids To Alkenes, Michael P. Stanton
Graduate Theses, Dissertations, and Problem Reports
Linear alpha olefins (LAOs) are important building blocks in the production of linear low-density polyethylene, a plastic used in products such as shrink wraps, plastic bags, tubing, plasticizers, among others. Commercial methods for generating LAOs utilize ethylene oligomerization, but this method is reliant on fossil fuels and leads to unselective product formation. Synthesis of LAOs from renewable resources, namely carboxylic acids, by decarbonylative dehydration strategies has been well studied, however, this method has inherent drawbacks rooted in the formation of internal olefin side-products through isomerization pathways. With the goal of avoiding internal isomerization, this thesis explores a dehydrogenative decarboxylation strategy …
Enantioselective Dearomatization Facilitated By Non-Covalent Interactions Of N-Heterocyclic Carbene Catalysts And Pyridinium Salts, Jack A. Patterson
Enantioselective Dearomatization Facilitated By Non-Covalent Interactions Of N-Heterocyclic Carbene Catalysts And Pyridinium Salts, Jack A. Patterson
Graduate Theses, Dissertations, and Problem Reports
Dihydropyridines are a practical organic scaffold commonly used for their pharmaceutical properties. Nucleophilic dearomatization of pyridines has proven to be a useful method in obtaining dihydropyridines. By using N-heterocyclic carbene (NHC) organocatalysts, dihydropyridines can be synthesized with high regioselectivity of the 1,4 regioisomer over the 1,2- regioisomer but often with low enantioselectivity. By incorporating non-covalent interaction contact points, we hypothesize that enantioselectivity can be enhanced. By synthesizing numerous NHCs, each proposed to exhibit a different type of non-covalent interaction (i.e., hydrogen bonding or ion pairing), an understanding of the secondary interactions within this reaction system can be studied and …
Synthesis And Pharmacology Of Illudalic Acid And Analogous Chemical Structures, Robert Gaston Jr
Synthesis And Pharmacology Of Illudalic Acid And Analogous Chemical Structures, Robert Gaston Jr
Graduate Theses, Dissertations, and Problem Reports
Natural products are the foundation of modern medicine and an inspiration for chemical innovation. Developing new synthetic strategies to complex natural products drives synthetic innovation and promotes pharmacological exploration. As bioactive secondary metabolites of fungi, illudalic acid and associated analogs have unrealized medicinal potential due to synthetic limitations. Illudalic acid is notably the first selective covalent inhibitor of the LAR-PTPs, a class of enzymes linked to many human illnesses, including stimulant addiction. The chemistry herein focuses on optimizing synthetic routes to illudalic acid and associated analogs toward exploring their pharmaceutical potential. We report a second-generation synthesis of illudinine (55% overall …
Enabling Technologies For Chemical Synthesis: I. Selective Microwave Heating; Ii. Synthesis And Regioselective Cyclotrimerizations Of Tethered 1,6-Diynes, Amir Tavakoli
Graduate Theses, Dissertations, and Problem Reports
Reaction discoveries, method developments, and technology advancements lie at the heart of synthetic organic chemistry. These innovations are essential for creating and manipulating complex molecules, which are the building blocks of many important chemical compounds, including pharmaceuticals, materials, and agrochemicals. Here, we first describe new methods to prepare neopentylene-tethered (NPT) 1,6-diynes which are valuable substrates for reaction discovery and target-oriented synthesis, especially in benzannulation strategies toward illudalane natural products. NPT 1,6-diynes have been employed as coupling partners in cyclotrimerization reactions for the synthesis of highly substituted benzene rings which present a persistent challenge in chemical synthesis and are underrepresented scaffolds …
Synthetic Methods For Improved Scope And Efficiency Of Copper-Catalyzed Regioselective Alkene Boracarboxylation, Steven William Knowlden
Synthetic Methods For Improved Scope And Efficiency Of Copper-Catalyzed Regioselective Alkene Boracarboxylation, Steven William Knowlden
Graduate Theses, Dissertations, and Problem Reports
The synthesis of carboxylic acids is important to the chemistry community, owing to the broad applicability of these compounds as fine chemicals and pharmaceuticals. Method development over the last decade has focused on the preparation of carboxylic acids through transition metal catalysis utilizing CO2 as a C1 synthon. Copper-catalyzed heteroelement(bora and sila)-carboxylation protocols provide functional group rich carboxylic acid products, yet remain underdeveloped and thus underutilized. Consequently, catalytic reductive difunctionalization methodologies in which CO2 and B(pin) (pin = pinacolate: 2,3-dimethyl-2,3-butanediolate) are installed across the double bond of a vinyl arene were recently developed. These boracarboxylation protocols provided novel, …
Multifunctional Organoboron Compounds And Boralactonate Salts, Randika T. Abeysinghe
Multifunctional Organoboron Compounds And Boralactonate Salts, Randika T. Abeysinghe
Graduate Theses, Dissertations, and Problem Reports
Organoboron compounds have gathered an important significance within the chemistry community on account of their wide range of applications in synthesis, catalysis, and medicinal chemistry. Even though the uses of boron compounds in drug discovery have been overlooked until the last several decades, boronic acid containing molecules have garnered increased attention due to the unique chemical properties of the boron center. Boron-functionalized ��-aryl propionic acid non-steroidal anti-inflammatory drug derivatives (bora-NSAIDs) can be accessed via copper(I)-catalyzed alkene boracarboxylation, using CO2 and B2pin2. To explore and expand the current synthetic and future medicinal chemistry applications of these bora-NSAIDs, methods …
Tandem Addition/Fragmentation Reactions Of Vinylogous Acyl Sulfonates, Kristen S. Nerbecki
Tandem Addition/Fragmentation Reactions Of Vinylogous Acyl Sulfonates, Kristen S. Nerbecki
Graduate Theses, Dissertations, and Problem Reports
Fragmentation methodology has been used in organic synthesis to produce complex organic compounds. This work is focused on fragmentation reactions leading to the subsequent construction of neopentylene-fused carbocycles, which are found in several important natural products and are difficult to prepare. These are produced by utilizing an optimized fragmentation methodology from the Dudley group. The methodologies build starting materials called nonaflates and triflates with a gem-dimethyl substituent that is seen in many natural products. Nonaflates and triflates are similar in structure, but nonaflates pose benefits that are an advantage over triflates, like cost effective synthesis and more stable compounds. A …
Synthesis And Cyclotrimerization Of Sulfonyl Enynes, Alexa C. Martin
Synthesis And Cyclotrimerization Of Sulfonyl Enynes, Alexa C. Martin
Graduate Theses, Dissertations, and Problem Reports
The synthesis of complex, polysubstituted aromatic rings from simple, non-aromatic building blocks is a consistent challenge to the synthetic community. Neopentylene ring fusions are found in several natural products but are largely absent from synthetic compound libraries. This discrepancy reflects the limitations in modern chemical synthesis. Utilizing, in part, a thoroughly developed fragmentation/olefination methodology from the Dudley Lab, a library of novel 1-sulfonyl-1,6-enynes have been developed. In this methodology, they are prepared in three steps from dimedone (5,5-dimethyl-1,3-cyclohexanedione), an inexpensive starting material. A total of 14 novel 1-sulfonyl-1,6-enynes were synthesized. These substrates were subjected to a novel benzannulation reaction based …
Biocompatible And Multifunctional Trityl Spin Probes For Electron Paramagnetic Resonance Spectroscopy, Teresa D. Gluth
Biocompatible And Multifunctional Trityl Spin Probes For Electron Paramagnetic Resonance Spectroscopy, Teresa D. Gluth
Graduate Theses, Dissertations, and Problem Reports
The primary objective of my thesis was to develop and utilize a biocompatible multifunctional trityl spin probe for concurrent measurement of pO2, pHe, and [Pi] in vivo by electron paramagnetic resonance (EPR) spectroscopy (Chapter 2). My first goal was to synthesize the proposed probe we are terming HOPE71. Secondly, HOPE71 was characterized by X-band and L-band EPR spectroscopy. Next, the biocompatibility of HOPE71 was assessed through an albumin binding test, cytotoxicity assays, and in vivo intravenous tolerance. Then, the use of HOPE71 to measure the target parameters was demonstrated in a breast cancer …
Enabling Technologies For Medicinal Chemistry And Synthesis: I. Cannabinoids; Ii. Illudalic Acid; Iii. Microwave Chemistry, Harvey Fulo
Graduate Theses, Dissertations, and Problem Reports
Innovations in synthetic organic chemistry such as methodology improvements, new chemical transformations and technology development significantly impact medicinal chemistry and continue to drive the drug discovery process. Here, new cyclization strategies to the pharmaceutically underexplored 3,3-dimethylcyclopentane-fused aromatic rings are described. One approach highlighted oxidative cycloisomerization, intermolecular [2+2+2] cyclotrimerization and 5-exo-dig cyclization providing indanoylindole cannabinoids that possess high affinity for human CB2 receptors at nanomolar concentration and good selectivity index. Another featured a [4+2]-type benzannulation reaction which enabled the 5-step synthesis of illudalic acid — compared to the current available sequences (≥16 steps) — and its equipotent and LAR-selective analogs. …
Silver-Mediated Decarboxylation Reactions: Expanding Reaction Scope Through Kinetic Analysis, Robert Anthony Crovak
Silver-Mediated Decarboxylation Reactions: Expanding Reaction Scope Through Kinetic Analysis, Robert Anthony Crovak
Graduate Theses, Dissertations, and Problem Reports
Transition metal-catalyzed decarboxylative coupling reactions have received considerable attention in recent years as a method to obtain biaryl compounds. However, the oxidative version of this reaction class is still in its infancy, limited to specific substitution patterns on the benzoic acids – ortho-substitution - used in these transformations. This thesis describes our attempts to understand the key decarboxylation step of this important class of reactions. The first chapter of this thesis discusses an introduction into cross-coupling reactions, decarboxylative cross-coupling reactions, and outlines relevant physical organic parameters. The following chapter details the synthesis of a series of (1,10-phenanthroline)silver(benzoate) complexes. This chapter …
Development Of New Synthetic Methods For Carbon Nanohoops, Merfat Aljhdli
Development Of New Synthetic Methods For Carbon Nanohoops, Merfat Aljhdli
Graduate Theses, Dissertations, and Problem Reports
Carbon nanotubes have received much attention from the material chemists after the synthesis and structure analysis by Iijima in 1991. It was envisioned that cycloparaphenylenes (CPPs), which comprise a sequence of benzene units connected at para position to make a cyclic ring structure, are possible templates for growing carbon nanotubes of a single chirality and single diameter for nanotechnology application. Recently, chemists turned their attention to synthesizing aromatic carbon nanobelts proposed as a general term for carbon molecules composed of fused benzene rings in cylindrical structure shape. Cyclophenacenes (CPAs) as carbon nanobelts are expected to be more suitable candidates for …
Cobalt-Catalyzed Aerobic Oxidative Cyclization Reactions Of Bisnucleophiles: New Methodologies And The Role Of Bisnucleophiles In O2 Activation, Jiaqi Liu
Graduate Theses, Dissertations, and Problem Reports
Over the past few decades, transition metals have found wide applications in the development of selective oxidative transformations mediated by molecular oxygen. Due to the benign nature of molecular oxygen as an oxidant and an increasing awareness of green chemistry practice, tremendous progress has been made towards the development of Cu-and Pd-catalyzed aerobic oxidation reactions. As a first-row transition metal alternative to copper, cobalt has been employed in aerobic catalytic transformations for its cost-efficiency and earth abundance; however, redox-active mediators such as benzoquinone (BQ), N-hydroxyphthalimide (NHPI) or salen-type ligands are usually required. To date, reactions mediated by Co/O2 catalytic …
Photoluminescent Zirconium Complexes For Visible Light Photoredox Catalysis, Yu Zhang
Photoluminescent Zirconium Complexes For Visible Light Photoredox Catalysis, Yu Zhang
Graduate Theses, Dissertations, and Problem Reports
Early transition metals like zirconium are attractive candidates for the design of luminescent molecules based on earth-abundant elements. Here, a series of zirconium complexes carrying two pyrrolyl-based ligands have been synthesized and characterized. These complexes are photoluminescent upon excitation with visible light and exhibit remarkably long emission lifetimes of hundreds of μs in solution at room temperature. Computational studies using time-dependent density functional theory (TD-DFT) were conducted to identify the nature of the luminescent excited states as mixed intra-ligand/ligand-to-metal charge-transfer (ILCT/LMCT) states. The electrochemistry studies revealed multiple reversible redox events for each zirconium complex. Furthermore, the excited state of the …
Copper-Catalyzed Regioselective Boracarboxylation Of Vinyl Arenes: Catalytic Efficiency And Synthetic Utility, Trina M. Perrone
Copper-Catalyzed Regioselective Boracarboxylation Of Vinyl Arenes: Catalytic Efficiency And Synthetic Utility, Trina M. Perrone
Graduate Theses, Dissertations, and Problem Reports
Hetero(element) carboxylation is an appealing transformation that involves the installation of CO2 and another hetero(element) in one step. This transition metal-catalyzed one-pot synthesis provides a route to achieve highly functionalized carboxylic acid products with an abundant and cheap C1 feedstock. This difunctionalization also avoids the use of reactive metal hydride species, which is a prominent limitation of hydrocarboxylation chemistry. A copper-catalyzed regioselective boracarboxylation of vinyl arenes has been developed to access pharmaceutically relevant β-boryl-α-aryl propionic acid products. One drawback of this reaction is the necessity for high catalyst loading to achieve catalytic turnover. To circumvent this issue, the reduction of …
In Situ Infrared Spectroscopic Study Of Iron-Catalyzed Hydromagnesiation Of Vinyl Arenes, Jessica Ann Rogers
In Situ Infrared Spectroscopic Study Of Iron-Catalyzed Hydromagnesiation Of Vinyl Arenes, Jessica Ann Rogers
Graduate Theses, Dissertations, and Problem Reports
Iron catalysis, especially homogeneous catalysis, has been a resurging topic of organometallic chemistry research. Discussions of past and present mechanistic analyses for homogeneous iron catalysis will be discussed in Chapter 1. As an expansion of homogeneous iron catalysis, in situ infrared spectroscopy will be used to develop a full mechanistic study of iron-catalyzed hydromagnesiation of vinyl arenes. The kinetic analyses by both initial and observed rate measurements indicate complex concentration dependencies on the (PDI)iron catalyst as well as sacrificial Grignard reagent and styrene. These complexities are not limited to non-linear catalyst and Grignard initial rate and inhibition by styrene/Grignard at …
Syntheses Of Azepinoindole Alkaloids Cimitrypazepine, Fargesine And Hyrtioreticulins C & D, Ganesh Ghimire
Syntheses Of Azepinoindole Alkaloids Cimitrypazepine, Fargesine And Hyrtioreticulins C & D, Ganesh Ghimire
Graduate Theses, Dissertations, and Problem Reports
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
Nickel-Catalyzed Oxidative Decarboxylative (Hetero)Arylation Reactions, Aaron P. Honeycutt
Graduate Theses, Dissertations, and Problem Reports
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 …
Search For New Membrane Active Substances: Synthesis Of 3-Tropanols With Alkyl, Alkenyl And Alkenynyl Group At The Bridgehead, Ramalinga Murty Dharanipragada
Search For New Membrane Active Substances: Synthesis Of 3-Tropanols With Alkyl, Alkenyl And Alkenynyl Group At The Bridgehead, Ramalinga Murty Dharanipragada
Graduate Theses, Dissertations, and Problem Reports
In recent years, Witkop and coworkers have isolated several structurally unique alkaloids from the colombian frog belonging to the genera Dendrobates. These alkaloids, which occur in the defensive skin secretions of the frog have been found to be highly active venoms as well as mucosal tissue irritants towards both mammals and reptiles. Among them are three important alkaloids histrionicotoxin, isodihydrohistronicotoxin and octahydrohistronicotoxin.