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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 …

Part I. The Development Of Non-Secosteroidal Vitamin D Receptor Modulators Part Ii. The Development Of A Universal Gtp-Ase Assay, Kelly Ann Teske

Theses and Dissertations

The vitamin D receptor is a nuclear hormone receptor that regulates cell proliferation, cell differentiation, calcium homeostasis and immunomodulation. The receptor is activated by the vitamin D metabolite, 1,25-dihydroxyvitamin D3, which induces a cascade of events including the recruitment of coactivators that activate transcription of specific VDR target genes. Thousands of VDR agonists have been synthesized based on the secosteroid scaffold of 1,25-dihydroxyvitamin D3. However, most of these ligands are metabolically unstable, have sub-optimal drug-like properties, and induce hypercalcemia in vivo. The limited numbers of VDR antagonists reported bear the same secosteroid scaffold and thus exhibit similar problems encountered by …

Porphyrin As A Spectroscopic Probe Of Net Electric Fields In Heme Proteins, Hannah Elizabeth Wagie

Theses and Dissertations

Heme proteins have diverse functions as well as varied structures but share the same organic, conjugated cofactor. Similarly varied approaches have been taken to deduce how heme can take on different roles based on its protein environment. A unique approach is to view the protein matrix as a constellation of point charges that generates a defined, reproducible, net internal electric field that has influence over the electronic properties of the heme cofactor. This work considers how porphyrins, the basic chromophore building block of heme, can be used as a native spectroscopic sensor of internal electric field at the active site …

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 …

Mechanistic Study Of Heme Protein-Mediated Nitric Oxide Dioxygenation Using Photolytically Produced Nitric Oxide, Karl Joseph Koebke

Theses and Dissertations

The previously reported NO precursor [Mn(PaPy2Q)(NO)]ClO4 (1), where (PaPy2QH) is N,N-bis(2-pyridylmethyl)-amine-N-ethyl-2-quinoline-2-carboxamide, was synthesized and proven capable of producing as much as 180 µM NO when irradiated by a single 3 mJ 500nm laser pulse, in a 0.15 cm path cell, without the need for additional sacrificial reductants or oxidants. Species 1 was first used to study the reaction of nitric oxide with oxy-myoglobin (oxyMb) to form ferric myoglobin (metMb) and nitrate. This reaction had long been assumed to proceed via the same iron-bound peroxynitrite intermediate (metMb(OONO)) as the metMb-catalyzed isomerization of peroxynitrite to nitrate. Recent research showed that the metMb-catalyzed …

Chiral Modification Of The Pd(111) Surface By Small Organic Molecules, Mausumi Mahapatra

Theses and Dissertations

Chiral modification of a metal surface is one of the most successful approaches of achieving enantioselective catalysis in heterogeneous phase. In this approach, an active metal surface is directly modified by adsorption of a chiral molecule (chiral modifier), the metal is responsible for catalytic activity while the adsorbed modifier controls the stereochemistry of adsorption and subsequent reactions through substrate interactions. So far, there are three types of widely recognized metal/modifier catalytic systems: tartaric acid modified Ni catalysts for the hydrogenation of β-ketoesters, cinchona modified Pt catalysts for hydrogenation of α-ketoesters and Pd catalysts modified with cinchona for selective activated alkene …

Improved Extraction Chromatographic Materials For The Separation And Preconcentration Of Metal Ions, Abdul Momen

Theses and Dissertations

Growing public health and safety concerns over the use of nuclear materials have increased the demand for improved methods for the separation and preconcentration of various metal ions from environmental and biological samples for subsequent determination. Historically, solvent extraction and ion-exchange have often been the methods of choice for these separations. Solvent extraction, however, is cumbersome and can generate substantial volumes of organic wastes. Ion-exchange, while less cumbersome, lacks adequate selectivity and requires careful control of pH for satisfactory separation. Moreover it is generally not compatible with acidic samples, such as are commonly encountered in the analysis of biological and …

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. …