Physical Sciences and Mathematics Commons^™

Methodology Studies For Dearomatized Dimer And Beta-Lactone-Mediated Native Chemical Ligation In Organic Synthesis, Xinhao Fan

Legacy Theses & Dissertations (2009 - 2024)

Chapter 1: Dimers of naphthalenol derivatives were synthesized by photocatalysis, cobalt(II) acetylacetonate. Several functional groups were tolerant of its skeleton. This novel dimer was connected through a reversible sigma bond. Its reversibility was confirmed by chiral HPLC and 1H-NMR experiments. Through EPR and Stern-Volmer quenching experiments, we proposed the reaction mechanism. The reversibility property can be potentially beneficial in polymers, self-healing, and memory materials.Chapter 2: We report an epimerization-free native chemical ligation reaction by β-lactone-mediated peptides. This approach can achieve Thr-Xaa efficiently and rapidly. Besides, it has a broad side-chain tolerance. Through the competition reaction experiment, it was demonstrated that …

Defining And Harnessing Nature's Selection Of Geranylation In Rna Modification, Phensinee Haruehanroengra

Legacy Theses & Dissertations (2009 - 2024)

Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. Geranylated-2-thiouridine is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, namely E. coli, E. aerogenes, P. aeruginosa and S. typhimurium by Liu group. It has been found as a post-transcription modification on the wobble position of anticodon of tRNAs specific for glutamic acid, glutamine and lysine. Geranylated-tRNA was shown to correct the frameshifting during the translation of E. coli. However, the reason of the existing of the modification is still largely unclear. To understand why nature incorporates such a hydrophobic group in …

Solvent Free Vanadium Mediated Organic Transformations, Garrett Oberst

Undergraduate Honors Thesis Collection

A mixture of vanadium(V) oxide and copper sulfate was used to catalyze oxidative transformations in a variety of organic compounds. Multiple functionalities were tested, including thiols, amines and alcohols. Various transformations were observed resulting in various oxidized products, including coupling reactions. Reactions were performed in a solvent-free environment due to the insoluble nature of vanadium(V) oxide in common organic solvents. Results were analyzed using HNMR and GCMS.

Optimization Of A Polydimethylsiloxane Based Passive Sampler Of Common Household Volatile Organic Compounds, Jennifer Lynn Osborne

Undergraduate Honors Thesis Collection

Dangerous volatile organic compounds, or VOCs, can accumulate as indoor air pollution within homes causing health problems in the habitants. In order to determine the concentration of VOCs in such areas a field-deployable sampler is necessary. The focus of this work has been to develop an inexpensive, reusable, sensitive fielddeployable passive sampler for monitoring VOCs in indoor air. We have devised a sampler that uses polydimethylsiloxane (PDMS), which is a common inexpensive, nonpolar adsorbent. The sampler is comprised of an aluminum bottle coated with the PDMS. In operation, the coated portion is exposed to the air to be sampled. The …

Understanding The Application Of Supported Palladium Catalysts In The Suzuki-Miyaura Cross-Coupling Reaction, Lubabalo Tseliso Bululu

Seton Hall University Dissertations and Theses (ETDs)

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Intramolecular Chemistry Of Ss-Acetoxyethylidene And Photochemical Generation Of Vinylidenes, Jennifer M. Nguyen

Honors Theses

The parent carbene ß-acetoxyethylidene has been previously generated by the photolysis of its precursor, acetic acid 1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl methyl ester. Mechanistic studies on ß-acetoxyethylidene have indicated the possibilities of three rearrangement pathways to the formation of vinyl acetate: a proton shift, an acyl shift, and a cyclic rearrangement (see Figure 8). A deuterium labeling study involving the replacement of the hydrogens on the methylene carbon has indicated that the simple 1,2-H shift was the primary manner of rearrangement, with an 82% yield of product. However, a primary kinetic isotope effect may have occurred due to the greater strength of a C-D …

Development And Application Of A Gg-Irms Reductive Pyrolysis Reactor Interface For The Δ34S Determination Of Sulfur In Individual Organic Compounds, N. Deborah Hewlett

Chemistry & Biochemistry Theses & Dissertations

The incorporation of sulfur into sedimentary organic matter is an important aspect of organic carbon preservation. A better understanding of the sulfur cycle and the formation of organo-sulfur compounds are necessary if we are to better understand the interaction of biogeochemical cycles of C, N, O, H. and S. Currently, the determination of ³⁴S/³²S in organic matter is limited to bulk organic samples. The sulfur isotopic analysis of individual organo-sulfur compounds within the sediments should allow for a more complete understanding of the sulfur cycle and the processes which lead to sulfur incorporation into organic matter. This …

Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic

Theses and Dissertations

Perchloroethene (PCE), Trichloroethene (TCE) and their degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands utilizing upward flow harbor reduction-oxidation conditions that have demonstrated the potential to promote both partial and total mineralization of PCE and TCE through the process of natural attenuation. Organic acid and inorganic anion concentrations are indicative of reduction-oxidation processes that drive chlorinated ethene degradation. These analytes were investigated to assess their development within three vertically stratified regions of a constructed wetland cell at Wright-Patterson Air Force Base fed by groundwater contaminated with PCE and TCE. Data collected during …

The Regioselective 3-Alkylation Of Piperidine, Richard Dunn Todd

Chemistry & Biochemistry Theses & Dissertations

The compounds: 3-allylpiperidine, 3-ethylpiperidine and 3-n-butylpiperidine have been synthesized by regioselectively alkylating the three position of piperidine. Piperidine was converted to N-chloropiperidine and then dehydrohalogenated to produce Δ¹-piperideine. The enamide anion was generated by adding solutions of Δ¹-piperideine to ethylmagnesium bromide or lithium diisopropylamide. Addition of alkylhalides produced 3-alkyl- Δ¹-piperideine which could be reduced or alkyllithiated to give 3-alkylpiperidines or 2,3-dialkylpiperidines respectively.

The yields of products were low and the reaction generated a continuum of mono- and di-alkylpiperidines and there was evidence that several dimeric piperideines were formed. The low yields were discussed in …

Synthesis Of Dihydroisoquinolines And Tetrahydroisoquinolines, John J. Schlager

Chemistry & Biochemistry Theses & Dissertations

Dihydroisoquinolines and tetrahydroisoquinolines are compounds which possess a variety of pharmacological activities. New easier methods of synthetic manipulations of these structures is of constant interest in the pharmaceutical industry.

This paper describes a new three step method of preparing 1-alkyl- and 1-aryl-tetrahydroisoquinolines from a tetrahydroisoquinoline. The synthesis involves the N-chlorination of tetrahydroisoquinoline followed by dehydrohalogenation with potassium superoxide. The reaction products are the dihydroisoquinolines. Overall yields range from 85-96%. The unsubstituted, 1-methyl-, and 1-phenyl-J,4-dihydroisoquinolines have been formed. Organometallation of the unsubstituted dihydroisoquinoline provides the 1-substituted tetrahydroisoquinoline. The 1-benzyl-, 1-n-butyl-, 1-ethyl-, 1-methyl-, and 1-phenyl-1,2,J,4-tetrahydroisoquinolines were prepared. The use of Grignard and …

Mechanism Of Phenyl Azide-1,2-Cyclonoadiene Adduct Formation And Isomerization Of This Adduct, Isom Harrison

University of the Pacific Theses and Dissertations

A major purpose of this research was to investigate the mechanism of aryl azide addition to allenes. Much evidence has accumulated in support of a concerted mechanism for aryl azide additions to simple alkenes. Consistent with these findings, this addition is a symmetry allowed process. The analagous aryl azide additions to allenes have received little mechanistic study. The approach taken in this work was to probe the mechanism by using optically active 1,2-cyclonanadiene, observing the stereochemistry of the adduct formed upon addition of phenyl azide.

Another goal was to investigate the isomerization of the phenyl azide-1,2-cylononadiene adduct, 10-phenyl-10,11,12-triaza-△ 11 -bicyclo …