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Herein is described our synthetic efforts toward the synthesis of (±)-nakadomarin A, a member of the manzamine alkaloids. The first chapter describes the isolation and biological significance of (–)-nakadomarin A. Chapter 2 describes the previous total syntheses as well as other partial syntheses of both (–)-nakadomarin A and its unnatural enantiomer. Chapter 3 discusses our approach to the formation of rings A and B in nakadomarin, as well as the installation of the quaternary center and the regioselective incorporation of a hydrazine moiety. Chapter 4 contains the development of a new methodology for the cleavage of hydrazine N-N bonds situated alpha to a carbonyl functionality. Chapter 5 describes the formation of rings D and E. Chapter 6 consists of experimental details and characterization data for all new compounds. / text

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Detailed information of the underlying mechanisms of macromolecular disintegration processes is not always fully available from lab-based experiments and GPC. A powerful computer simulation technique was thus indispensable in this respect whilst saving time, labour and expense. This project aims to develop an interactive computer program to capture the behaviour of a complex reactor and offer the following functionality: mathematical calculations, graph/chart generation, processing simulation-experiment pertaining to user-given scission and environmental characteristics, data saving and re-loading etc, Windows-style menu-driven interfaces provide templates for easy implementation of complex mathematical algorithms -a new simulation technique (Slider interfaces) presented in the thesis, based on cellulose-ageing study in electrical transformers (Heywood, 2000). A novel statistical concept was introduced to significantly improve real-tune performance of mathematical calculations to simulate polymer chain fragmentation phenomena, enabling transformation of the simple iterative to a semi-iterative and instant calculation algorithm. Three new mathematical functions were constructed - (a) Monte Carlo Dynamic (Slider), (b) Algebraic Exact, (c) Markov Statistical models, initially using an arbitrary time scale for degradation. Real-time simulation was developed using three time model variants that included the interpretation of deviations in the order reaction rate from linearity to an exponential type function. The above transformation enhanced reproducibility and accuracy of degraded MWD curve sampling whilst then- graphical display & clarity via 'Cubic B-Spline' smoothing-algorithm. Complex models were created from a ranking ensemble of single scission mechanisms, structured with levels of probability constructs to effectively simulate GPC-like curve-deformities and side-shifts. The simulation results provided new information in the following key areas: the temporal shift patterns of MWD/PCLD under different ageing conditions graphical comparisons between simulated and observed Idnetic and scission parameters. the dominant types of scission strategy at different reactor conditions, the dependence of reaction behaviour on the polymer structural order. An alternative way of predicting life expectancy of an ageing polymer via relating time- temperature to the magnitude of intermediate MWD curve shifts that is independent on DP. The latter is an average value and subjected to errors. An equation was derived for this. Introduction of a binary tree "death time" algorithm for calculation of the life expectancy of different categories of polymer chain species. Non-iterative techniques developed here opens up new avenues of further research. The developed algorithms and computer program may provide ample scope for investigating the ageing of other industrially important polymers and can be utilised in other areas of polymer research with little modification where probability distribution is sought.

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Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains ix, 82 p. : ill. Includes abstract. Includes bibliographical references (p. 70-80).

Thesis (M.S.)--Florida State University, 2005. / Advisor: Albert E. Stiegman, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Jan. 24, 2006). Document formatted into pages; contains xiv, 89 pages. Includes bibliographical references.

Indiana University-Purdue University Indianapolis (IUPUI) / Metallopeptides of the general form M(II)∙Gly1-Gly2-His induce DNA strand scission via minor groove interactions. This peptide system can serve as a nucleic acid-targeted cleavage agent – either as an appendage to other DNA binding agents, or as a stand alone complex. In an effort to further our knowledge of DNA recognition and cleavage, a novel series of phenyl-benzimidazole modified Gly-Gly-His-derived metallopeptides was synthesized via solid phase methods and investigated. The new systems allow the formation of additional contacts to the DNA minor groove through the incorporation of a DNA binding phenyl-benzimidazole moiety, thus strengthening the overall binding interaction and further stabilizing the metal complex-DNA association. In addition, how Lys side chains and an amidinium group influence the efficiency of DNA cleavage was also studied. DNA cleavage studies suggested that the phenyl-benzimidazole-modified Gly-Gly-His metallopeptides possess enhanced DNA cleavage abilities. In particular, when amidines are placed on the benzimidazole moieties, these moieties appeared to play an important role in increasing the DNA cleavage activity of the metal complex, most likely through an enhanced electrostatic attraction to the DNA.

Chapter 1 is the introduction to the thesis. The general principles of radical cyclisation reactions are highlighted with a focus upon the reactivity of iminyl radicals. A more detailed discussion follows on radical cyclisations onto nitriles including examples of tandem cyclisations. The final section is concerned with cyano migration reactions, and provides evidence for the reversibility of these translocations. The investigation into tandem radical cyclisations of nitriles is discussed in Chapter 2. The aim of the project was to form bicyclic nitrogen heterocycles from acyclic precursors by utilising the nitrile function as a radical acceptor which could then undergo further cyclisation onto a suitably placed alkene. We found a surprising chemoselectivity for 1,5-exo-cyclisation of alkyl, aryl and vinyl radicals onto the cyano group over 1,6-exo-cyclisation onto suitably placed alkenes. The presence of an electron-withdrawing group on the carbon a- to the nitrile group resulted in an overall 1,4-cyano migration reaction. The intermediate cyclic iminyl radical does not undergo further cyclisation, nor does it abstract hydrogen from tributyltin hydride. Instead, fragmentation by β-scission yields a stabilised radical, e.g. by an ester or nitrile group. In order to investigate the effect of substituents on the cyclisation of aryl radicals onto nitriles, and the β-scission reactions of the iminyl radical intermediates, a series of aryl radical precursors were prepared. a-Nitrile, amide, sulfone and phenyl groups favoured β-scission and a-alkyl groups favoured cyclisation or reduction of the aryl radicals. The study indicated the existence of a Thorpe-Ingold effect on the cyclisation of aryl radicals onto nitriles. In Chapter 3 the largely unsuccessful studies of the reversibility of radical cyclisations onto nitriles is reported. Finally, in Chapter 4, the results obtained from our research into vinyl radicals as precursors for tandem radical cyclisations of nitriles are presented. A vinyl iodide underwent complete conversion when standard radical cyclisation conditions were applied; the cyclic ketone resulting from a single 5-exo cyclisation was isolated in the absence of any other products. The experimental relevant to the discussion is detailed in Chapter 5.

Th. doct.-ing--Génie chim.--Toulouse--I.N.P., 1980. N°: 116.