Physical Sciences and Mathematics Commons^™

Photo-Reactivity Of Bifunctional Naphthalene Compounds Toward Dna, Qi Zhang

Theses and Dissertations

DNA interstrand cross-link (ICL) can covalently bind two DNA strands, preventing DNA strands separation, and therefore, blocking DNA transcription and replication, which are essential biological processes for cell division. Among different methods to induce DNA interstrand cross-linking, photoinduction is an important way to activate the cross-linking reactions due to its many characteristics, such as non-invasive, controllability, selectivity and biorthogonality. My research mainly focuses on developing novel binaphthalene compounds which can be activated by 350 nm UV light to produce DNA interstrand cross-linking via alkylation. We designed and synthesized a series of binaphthalene analogues with different substituents at the position-4’ on …

Inducible Dna Interstrand Cross-Linking Agents: Design, Synthesis, Mechanism, And Biomedical Applications, Muhammad Asad Uz Zaman

Theses and Dissertations

DNA is the carrier of genetic information, making its chemical reactivity and function extremelyimportant. DNA interstrand cross-links (ICL) leads to covalent bind of two strands, which prevents the separation of double helix. DNA ICLs are the sources of the cytotoxicity of antitumor and anticancer agents. This thesis focuses on investigating the reactivity of a varieties of aromatic compounds towards DNA. Some of these molecules can be activated by photo irradiation to induce DNA ICL formation via alkylation. Others undergo activation by H2O2 to release DNA cross-linking agents. We investigated the mechanism of function of these inducible DNA cross-linking agents as …

Guest Host Chemistry Part I: The Synthesis Of Metal Selective Sensors Part Ii: The Synthesis Of Antibiotic Precursors And Intermediates, Trevor Moss Hagemann

Theses and Dissertations

Part 1: Metal Selective Sensors

The work herein describes the creation of a library of sensors for the detection of metal ions in aqueous systems. The solid support these dyes are attached to facilitates a continuous measurement of metal ion concentrations in aqueous systems. The sensors are based on an azo dye core structure wherein detection of metal ions is observed by the change in absorbance of the dye upon binding. These sensors are capable of detecting metal ions in the ppb range, specific dyes interacting with specific metal ions cause distinct spectral changes, providing substantial information. the aggregate response …

Design And Synthesis Of Achiral And Chiral Benzodiazepines And Imidazodiazepines To Modulate The Activity Of Gabaa Receptors For The Treatment Of Cancer, Cns Disorders And Pain, Farjana Rashid

Theses and Dissertations

A series of α2/3-subtype selective GABAA receptor agonist imidazodiazepines (IBZs) were synthesized and investigated. The lead compound (KRM-II-81) exhibited anxiolytic, antinociceptive and anticonvulsant effects, displayed promising α2/3 GABAergic subtype selectivity in HEK cells and noteworthy anxiolytic activity and no sedation nor ataxia using a rotarod assay in mice (80mg/Kg) or rats (300 mg/Kg).Based on the "privileged imidazodiazepine (IMZD) structures" derived from the unified pharmacophore model of Milwaukee, the design, synthesis and biological activities of more than 30 novel 2’ Cl achiral GABAAR α2/α3 subtype selective imidazodiazepines (IMDZs) related to KRM-II-81 achiral ligand Hz-166 are described. Several compounds from the α2/3 …

Part I: Development Of Small-Molecule-Based Probes For The Vitamin D Receptor; Part Ii: Development Of A Scalable Manufacturing Process For Orcein Dye, Tania Roseann Mutchie

Theses and Dissertations

PART I:The vitamin D receptor (VDR) is a ligand-dependent transcription factor and member of the nuclear hormone receptor superfamily. VDR is expressed in the epithelia of endocrine organs, digestive system, bronchi, kidneys, and thymus, as well as being present in leukocytes and bone cells. Cell proliferation, cell differentiation, and immunomodulation, along with calcium and phosphate homeostasis, are all processes regulated by the receptor. Within the cell, VDR can be membrane-bound or located in the nucleus. Nuclear localization of VDR transpires following the binding of vitamin D metabolites, the most active of which is 1α,25-dihydroxyvitamin D3 (calcitriol). Within the nucleus, interactions …

Approach Toward The Total Synthesis Of Some Sarpagine Related Indole Alkaloids: Histrixnine, Gelsempervine A, Gelsempervine B, O-Methylmacusine B & 19,20-Dihydro-O-Methylmacusine B,Design, Synthesis & Biological Study Of Some Novel Gamma-Aminobutyric Acid Type (Gabaa) Receptor Ligands, Md Zubair Ahmed Khan

Theses and Dissertations

Indole alkaloids are chemically, biologically and commercially significant, as well as diversely distributed important group of natural products. These are of prominence because of their resemblance with various biologically essential molecules including tryptophan, tryptamine, and serotonin. The Sarpagine type indole alkaloids comprise one of the most diverse series of indole alkaloid natural products. These indole alkaloids are primarily isolated from three plant families: Apocynaceae, Rubiaceae, and Loganiaceae which have been used in traditional and folk medicines in many countries around the world. Biological screening of these alkaloids is not always possible, presumably, due to the paucity of the isolated natural …

Chapter 1: Part A: A Unique Approach Of Preparing 3,3-Disubstituted Oxindoles From Acyclic Tetrasubstituted Aldehydes: Total Synthesis Of (-)-Coerulescine And (-)-Coixspirolactam A, Chapter 1: Part B: Synthetic Scope Of Brønsted Acid Catalyzed Reactions Of Carbonyl Compounds And Ethyl Diazoacetate,, Md Shahnawaz Ali

Theses and Dissertations

CHAPTER 1: PART A: A UNIQUE APPROACH OF PREPARING 3,3-DISUBSTITUTED OXINDOLES FROM ACYCLIC TETRASUBSTITUTED ALDEHYDES: TOTAL SYNTHESIS OF (-)-COERULESCINE AND (-)-COIXSPIROLACTAM A(-)-Coerulescine and (-)-coixspirolactam A, two naturally occurring compounds characterized with an all-carbon quaternary center containing a spirooxindole, have been synthesized asymmetrically. The key feature of their total synthesis involves a novel rational construction of the chiral 3,3-disubstituted oxindole core from the acyclic chiral tetrasubstituted aldehyde. The later scaffold was prepared in high enantioselectivity (up to 86%) from the ethyl 3-hydroxy-2-(2-nitrophenyl)acrylate 1 by exploring both intermolecular and intramolecular Pd-mediated asymmetric allylic allylations (Pd-AAA). A through optimization of these approaches is …

Characterization Of Dna Interstrand Cross-Linking Agents By Liquid Chromatograhy-Mass Spectrometry, Anahit Marina Campbell

Theses and Dissertations

This study is to characterize novel reactive oxygen species (ROS)-activated nitrogen mustard analogues and UV-activated alkylating agents by Liquid Chromatography-Mass Spectrometry (LC-MS). First, we optimized the instrument conditions to successfully ionize a few novel binapthalene analogues and methoxybenzene analogues by MS. The highest signal intensity for compounds 3-10 was observed when atmospheric pressure chemical ionization (APCI) with an optimized corona needle position of 5mm or 10 mm was used, which led to successful analysis of compounds 3-10 by MS. Second, we determined pharmacokinetic properties of a drug compound (FAN-NM-CH3), including animal study, assay development, optimization of MS/MS instrumental parameter and …

Part I: A Concise Asymmetric Synthesis Of Microtubule Inhibitor Tryprostatin B Part Ii: Synthesis And Biological Assessment Of Histone Deacetylase (Hdac) Inhibitors Part Iii: Acid Catalyzed Reactions Of Aromatic Ketones With Ethyl Diazoacetate, Md Mizzanoor Rahaman

Theses and Dissertations

PART I: A CONCISE ASYMMETRIC SYNTHESIS OF MICROTUBULE INHIBITOR TRYPROSTATIN B

Tryprostatin (TPS) A and B, microtubule inhibitor, are the members of a family of prenylated Trp-Pro diketopiperzine alkaloids. These two natural products were isolated in 1995 from the fermentation broth of Aspergillus fumigatus BM939 by Osada and coworkers. TPS and related diketopiperazine containing compounds such as phenylahistins, spirotryprostatins, and cyclotryprostatins are inhibitors of the mammalian cell cycle. They prevent cell cycle progression at the G2/M phase through a unique mechanism consisting of inhibiting the interaction between microtubule assisted proteins (MAP-2) and the C-terminal end of tubulin. TPS A and …

A Study In Molecular Recognition: Synthesis Of A Β-Sheet Mimic & Quantitation Of Metal Ions In Aqueous Solutions Through Solid Supported Semi-Selective Chemosensors, Tyler G. Fenske

Theses and Dissertations

From the hydrophobic effect, which is responsible for the organization of amphipathic molecules into cellular membranes, to the highly specific hydrogen binding patterns found in DNA base pairs that keeps our genetic material “zipped up”, non-covalent and reversible interactions are critical to properly functioning biological processes. Molecular recognition is an area of study that seeks to better understand these observed phenomena. In a general sense, association of “Host” and “Guest” molecules are based on ionic forces, hydrophobic interactions, cation-π effects, π-π stacking, conformational restriction, and many others. This dissertation will primarily focus on two projects that have an emphasis on …

Part I: An Investigation Of Calcitroic Acid And Its Phase Ii Conjugates. Part Ii: Toward The Development Of A Novel Orally-Available Asthma Treatment Targeting Gabaa Receptors In The Lungs, Olivia B. Yu

Theses and Dissertations

PART I

Calcitroic acid (CTA) was isolated and characterized more than four decades ago.5 Radiolabeled calcitriol (1,25-dihydroxyvitamin D3) was used at that time to enable the identification of radioactive CTA formed in vivo, which was subsequently extracted and characterized by derivatization.7 CTA was found to be predominantly formed in the liver and secreted into the gut through the bile duct via enterohepatic circulation, leading to fairly high concentrations of this metabolite of vitamin D in the intestine.8 However, assuming it was only a catabolic product of calcitriol, it was ignored thereafter.

Recently, novel experiments showed that CTA can bind the …

Part I: Design And Synthesis Of Novel Drugs To Treat Asthma By Targeting Gabaa Receptors In The Lung Part Ii: Design And Synthesis Of Novel Α2/Α3 Subtype Selective Gabaar Ligands For Cns Disorders, Rajwana Jahan

Theses and Dissertations

Part I. Asthma is a major healthcare challenge affecting an estimated 300 million people globally. Over $56 billion in asthma-related healthcare expenses occur in the United States annually. Moreover, asthma accounts for the majority of missed school/work days, Doctor and emergency room visits, and patient hospitalizations in young persons. Consequently, asthma continues to be a significant healthcare burden in terms of morbidity, productivity, and medical costs. Beta 2-adrenergic agonists and inhaled corticosteroids (ICs) are the most commonly prescribed treatments for the acute and chronic management of asthma. Both agents present efficacy, compliance, and adverse side effect concerns.

Hence, there is …

Active Polymeric Materials For 3d Shaping And Sensing, Adebola Oyefusi

Theses and Dissertations

Part I: Reprogrammable Chemical 3D Shaping for Origami, Kirigami, and Reconfigurable Molding

Origami- and kirigami-based design principles have recently received strong interest from the scientific and engineering communities because they offer fresh approaches to engineering of structural hierarchy and adaptive functions in materials, which could lead to many promising applications. Herein, we present a reprogrammable 3D chemical shaping strategy for creating a wide variety of stable complex origami and kirigami structures autonomously. This strategy relies on a reverse patterning method that encodes prescribed 3D geometric information as a spatial pattern of the unlocked phase (dispersed phase) in the locked phase …

Part I: An Investigation Of Calcitroic Acid And Its Phase Ii Conjugates. Part Ii: Toward The Development Of A Novel Orally-Available Asthma Treatment Targeting Gabaa Receptors In The Lungs, Olivia B. Yu

Theses and Dissertations

PART I

Calcitroic acid (CTA) was isolated and characterized more than four decades ago.5 Radiolabeled calcitriol (1,25-dihydroxyvitamin D3) was used at that time to enable the identification of radioactive CTA formed in vivo, which was subsequently extracted and characterized by derivatization.7 CTA was found to be predominantly formed in the liver and secreted into the gut through the bile duct via enterohepatic circulation, leading to fairly high concentrations of this metabolite of vitamin D in the intestine.8 However, assuming it was only a catabolic product of calcitriol, it was ignored thereafter.

Recently, novel experiments showed that CTA can bind the …

Shorter And Improved Access To The Key Tetracyclic Core Of Sarpagine-Macroline-Ajmaline Indole Alkaloids: The Total Synthesis Of Alkaloids Macrocarpines A-G, Talcarpine, N(4)-Methyl-N(4),21-Secotalpinine, Deoxyperaksine, Dihydroperaksine, Talpinine, O-Acetyltalpinine, And N(4)-Methyltalpinine, Md Toufiqur Rahman

Theses and Dissertations

Extension of the asymmetric Pictet-Spengler (P-S) reaction to bulkier Nb-alkylated tryptophan derivatives resulted in a shorter and improved stereospecific access to the key bicyclo[3.3.1]nonane framework of bioactive C-19 methyl substituted sarpagine/macro-line/ajmaline indole alkaloids with excellent diastereoselectivity via internal asymmetric induction. The asymmetric Pictet-Spengler/Dieckmann protocol with bulky Nb-alkyl substituted systems enabled a more direct and two-step shorter route to this key architecture. Complete stereocontrol of the C-19 methyl function in either the α- or β-configuration was achieved which would enable one to gain rapid access to the crucial intermediates for the total synthesis of any member of this group of seventy …

Studies In Molecular Recognition: Non-Proteogenic Amino Acids For Antibiotic Studies And Chemosensors For Recognition And Reporting Of Metal-Ions, Sarah Anne Oehm

Theses and Dissertations

The field of molecular recognition focuses on the selective and reversible binding of small guest molecules to larger host molecules. This dissertation describes synthesis of small molecules as binding guests for enzymatic substrates as well as molecules as host chemosensors to detect and identify metal ions. Two approaches to new antibiotic drugs have been explored, and an array of sensors for the quantitation of aqueous metals is being commercialized.

As strains of deadly bacteria emerge with evolved resistance to known antibiotics, new drugs are needed with novel mechanisms of action. Natural product antibiotics containing enduracididine, a non-canonical amino acid derived …

Short Synthesis And Biological Evaluation Of 5-Chloro-7-Benzoyl 2,3-Dihydrobenzo[B]Furan -3-Carboxylic Acid(Brl-37959) And Its Analogs., Shamsul Arefin Ahmed

Theses and Dissertations

The synthesis of BRL-37959 has previously been reported. As an NSAID, the compound was tested for and found that it had very low gastric irritancy. Commercially available NSAIDs are non-selective COX inhibitors that enhance the risk of gastric, duodenal mucosal injury or erosions and ulcer problems as well as lead to nephrotoxicity. The COX-2 selective inhibitor Celecoxib (Celebrex) increases the risk of serious cardiovascular (CV) thrombotic events, myocardial infarction and stroke as well as increased nephrotoxicity. COX inhibitors are active against inflammation, pain, fever and different types of cancers. Considering the enormous potential benefits and side effects of non-selective COX …

Part – I: Development Of A Two-Step Regiospecific Synthetic Route For Multigram Scale Synthesis Of Β-Carboline Analogs For Studies In Primates As Anti-Alcohol Agents,Part – Ii: Design And Synthesis Of Novel Antimicrobials For The Treatment Of Drug Resistant Bacterial Infections Part – Iii: A Novel Synthetic Method For The Synthesis Of The Key Quinine Metabolite (3s)-3-Hydroxyquinine, Veera Venkata Naga Phani Babu Tiruveedhula

Theses and Dissertations

PART – I

Development of a Two-Step Regiospecifc Synthetic Route for Multigram-Scale Synthesis of β-Carboline Analogs for Studies in Primates as Anti-Alcohol Agents

β-Carboline and their derivatives are important structural motifs in synthetic organic and medicinal chemistry because of their novel biological activity, especially in regard to the reduction of alcohol self-administration [binge drinking (BD)], a major problem increasing day by day in modern society. This anti-alcohol effect is proposed to be due to the activity of ligands at the benzodiazepine site of the GABAA receptor in the central nervous system acting as antagonists at the α1 subunit. The past …

Part 1: Design, Synthesis, And Evaluation Of Novel Gram-Positive Antibiotics Part 2: Synthesis Of Dihydrobenzofurans Via A New Transition Metal Catalyzed Reaction Part 3: Design, Synthesis, And Evaluation Of Bz/Gabaa Α6 Positive Allosteric Modulators, Christopher Michael Witzigmann

Theses and Dissertations

Part 1. Lead compound SK-03-92 represents a new scaffold for antibiotic drug discovery. Development of a new process for the synthesis of analogs has led to the development of a number of new ligands with even more potent activity against gram-positive bacteria, including drug-resistant strains of S. aureus. Compounds 36 and 38 represent some of the most potent analogs developed thus far, and preliminary results indicate that they are also not cytotoxic. Research into a Heck-mediated transition metal catalyzed pathway towards electron-rich stilbenoid analogs has greatly expanded the scope of future SAR studies. This development has led to 14 new …

Synthesis Of Subtype Selective Bz/Gabaa Receptor Ligands For The Treatment Of Anxiety, Epilepsy And Neuropathic Pain, As Well As Schizophrenia And Asthma, Michael M. Poe

Theses and Dissertations

The α2/α3 subtype selective Bz/GABAA receptor positive allosteric modulator HZ-166 (3) has been shown to be a nonsedating anxiolytic with anticonvulsant and antihyperalgesic activity. However, instability in vitro and in vivo has hindered its advancement into clinical trials. A series of ligands based off HZ-166 (3) were synthesized. Many of these ligands were designed to increase metabolic stability, while others were synthesized to study the effects that electronics and sterics have on the efficacy exerted when bound to the GABAA receptor. The α3 subtype selective methyl ester MP-III-024 (19) was shown to have increased resistance to metabolism in in vitro …

Arylboronates As H2o2 Or Photo-Inducible Dna Cross-Linking Agents: Design, Synthesis, Mechanism, And Anticancer Activity, Yibin Wang

Theses and Dissertations

Interest in the development of cancer therapies with improved selectivity and reduced host toxicity has been growing. In this thesis, we designed and synthesized a series of novel non-toxic arylboronic ester and biarylboronic ester derivatives that can be activated by hydrogen peroxide (H2O2) to induce DNA interstrand cross-link formation. The mechanism of DNA cross-linking induced by these arylboronates involves generation of phenol intermediates 1 followed by departure of leaving group (L) leading to quinone methides (QMs) 2, which directly cross-link DNA via alkylation. The QM formation is the rate-determining step for DNA cross-linking. The activity and selectivity of these compounds …

Enantiospecific Stereospecific Strategy For The Total Synthesis Of Sarpagine And Macroline Related Oxindole Alkaloids: First Total Synthesis Of Affinisine Oxindole, Isoalstonisine, Alstofoline, Macrogentine, N(1)-Demethylalstonisine, Alstonoxine A And Second Generation Synthesis Of Alstonisine, German Oscar Fonseca Cabrera

Theses and Dissertations

The (7R)-sarpagine/macroline related oxindole alkaloids (-)-isoalstonisine (27) and (-)-macrogentine (31) together with the (7S)-sarpagine/macroline related oxindole alkaloids (-)-affinisine oxindole (24), (-)-alstonoxine A (19), (+)-alstonisine (8, second generation total synthesis), (+)-Na-demethylalstonisine (17) and (+)-alstofoline (18) were concisely synthesized during these studies.

These oxindole alkaloids were isolated from plants of the genus Alstonia which is characterized by the preponderance of sarpagine/macroline-type indole and oxindole alkaloids. Plants that belong to this genus are mainly distributed over tropical regions of Central America, Africa, and Asia where they are used locally in traditional medicine, for example, in the treatment of malaria and dysentery. The main …

Asymmetric Synthesis Of All-Carbon Α-Aryl Quaternary Carbonyl Compounds By Palladium-Catalyzed Asymmetric Allylic Alkylation (Pd-Aaa) And Their Application To The Synthesis Of Biologically Important 3,3′-Disubstituted Oxindole And Α-Disubstituted Quaternary Β-Lactone Frameworks, Md. Sharif Al Asad

Theses and Dissertations

The development of catalytic, enantioselective methods for the construction of all-carbon quaternary stereocenters is an outstanding achievement in the recent history of organic chemistry. The palladium-catalyzed asymmetric allylic alkylation (Pd-AAA) reaction has played a key role in creating such stereocenters and has allowed researchers to synthesize a vast number of biologically potent natural products. However, synthetic methodologies to access compounds containing α-aryl groups to the quaternary carbon stereocenters are still rare. The increasing appearance of these all-carbon α-aryl quaternary stereocenters in a growing number of biologically active natural products and pharmaceutical agents creates a pressing need for the ability to …

I. Palladium (0)-Catalyzed Asymmetric Rearrangement Of Allyl Enol Ether For The Synthesis Of Α -Aryl Quaternary Carbon Center. Ii. Synthesis Of Chiral Tryptophan Analogs And Studies Towards Synthesis Of Tryprostatin A And B, Md Nazim Uddin

Theses and Dissertations

The development of efficient catalytic enantioselective synthesis of all carbon quaternary centers is a significant challenge in chemical synthesis due to the difficulties of carbon-carbon bond formation at quaternary center. Using phase transfer catalyst we attempted to create quaternary carbon center via direct C-alkylation of hydroxyarylacrylates, instead we obtained O-alkylated acrylates. We succeeded in C-alkylation which involves an indirect method via the O-alkylation of 3-hydroxy aryl acrylates and a subsequent [3, 3] sigmatropic rearrangement (Claisen rearrangement). The O-alkylated products are obtained in yields ranging from 65-85%, and the corresponding Claisen rearrangement products in yields ranging from 55-90%. Typically Pd(II) catalysts …

Application Of Coumarin Derivatives In Dna-Associated Study: Mutation Detection, Site-Specific Labeling, Photoinduced Interstrand Cross-Links And Ligation Reactions, Huabing Sun

Theses and Dissertations

Coumarin derivatives have been widely utilized as cross-linking agents in polymer science, being fluoroprobes in biochemistry and as medicines in pharmacy. But the coumarin's fluorogenic properties and reactivities in DNA were rarely reported and unclear, which limits its bioapplications due to possible side reactions towards biomolecules. In this thesis, we investigated the activity of coumarin moiety towards natural DNA and expanded its application in DNA-associated study. We have found that coumarin derivatives can serve as perfect DNA cross-linking agents, as alkylation agents for site-specific labeling, and fluoroprobes for single nucleotide polymorphism (SNP) analysis, which provided a novel insight of biotoxicity …

Asymmetric Synthesis Of Tryptophan Driviatives And Its Application To Streamlined Synthesis Of Tryprosatain A And B, Matthew Huisman

Theses and Dissertations

Tryprostatins have been shown to be potential antitumor antimitotic agents. Tryprostatins have been isolated from the fermentation broth of marine fungal strain Aspergillus fumigatus in trace amounts. Our lab has developed a phase-transfer-catalyzed asymmetric alkylation reaction to produce protected tryptophans (Trp) with high enantioselectivity (90-95% ee) as synthetic precursors to Tryprostatins. Studies of Tryprostatins indicate that manipulation of ring-A may cause enhanced activity. We propose a general synthetic route to several new tryprostatins that may be tolerant to ring-A analogues of gramine utilizing achiral reactants. The synthesis of Tryprostatin B has been completed with 20% overall yield in 7 steps. …

The Synthesis Of Alpha 5 Subtype Selective Gaba(A) /Benzodiazepine Receptors Ligands, Poonam Biawat

Theses and Dissertations

GABAA complexes are a class of receptors that respond to the neurotransmitter GABA, the chief inhibitory neurotransmitter in the vertebrate CNS. A widely accepted pharmacological target for enhancing cognition is the benzodiazepine-binding site on the gamma-aminobutyric acid type A (GABAA) receptor complex. Inverse agonists acting at 5 subunits containing GABAA receptors are thought to act as cognitive enhancers while eliminating unwanted side effects associated with non-selective compounds. From the recent work of Rowlett, Cook et al. it was demonstrated that the novel 5 selective inverse agonist PWZ-029 (20) was active as a cognitive enhancer in rhesus monkeys in the CANTAB …

Part I: Studies Towards Asymmetric Α-Halogenation And Mechanistic Studies Of The Acrylate System With Organocatalyst And Part Ii: Synthesis Of Α-Aryl Quaternary Carbon Centers, Maria Shevyrev Shteynbuk

Theses and Dissertations

Organocatalytic transformations and asymmetric α-halogenation have become an important and dynamic research topic in organic chemistry in recent years. Despite the growing research in asymmetric halogenation of carbonyl compounds, such as aldehydes and ketones, there are no current examples in the literature of asymmetric halogenation of enolic systems even though many proposed reaction mechanisms go through enolate form. The research presented is the first example of enantioselective α-chlorination and α-bromination of α-hydroxyacrylate using organocatalysis and NMR studies towards achieving asymmetric induction of the enolic system. Despite the many publications that show when an organocatalyst binds to an aldehyde or ketone, …

I. Studies On The Organocatalytic Formation Of Quaternary Stereocenters. Ii. Studies On The Claisen Rearrangement As A Route To Quaternary Stereocenters. Iii. Asymmetric Synthesis Of Aldehydes Bearing Quaternary Carbon Centers Via The Decarboxylative Asymmetric Allylic Alkylation, Eduardo Alberch

Theses and Dissertations

The asymmetric synthesis of all carbon quaternary stereocenters poses a particular challenge due to the steric congestion inherent in the formation of such centers and has been the object of intense research these last 20-30 years. However, the amount of literature for the synthesis of aldehydes bearing quaternary stereocenters via enolate type chemistry is much more limited due to problems associated with the alkylation of such substrates including such types as Cannizzaro and Tischenko related reactions or self aldol condensations. The formation of aldehydes with quaternary stereocenters via use of enolate equivalents such as the DAAA (decarboxylative asymmetric allylic alkylation) …

Infrared Light Induced Bending Of Liquid Crystalline Elastomer Composite-Silicone Bilayer Films, Maika Moua

Theses and Dissertations

This research centers on infrared (IR) light-induced bending of liquid crystalline elastomers (LCE) composite-silicone bilayer films. Two new developments are presented in this thesis. First, the reversible infrared (IR) induced bending of 0.1% (w/w) single walled nanotube (SWNT)-LCE/silicone bilayer films were successfully prepared and used for fabrication of functioning devices such as folding, grabbing, and crawling structures. Second, the use of adding a filler (absorbs specific wavelength range), such as Dye 1002, into the LCE matrix achieved wavelength selectivity in LCE systems. The 0.2% (wt/wt) Dye 1002-LCE/silicone bilayer films demonstrated bending under a 980 nm laser source but no bending …