Thesis (doctoral)--Universität, Köln, 2001.

This doctoral dissertation described herein will be comprised of two parts. The first portion will address our efforts towards the synthesis of [alpha]-amino carbonyls from silyl enol ethers and the second portion will describe our unrelated efforts towards the synthesis of proaporphine alkaloids. A full discussion of the relevant literature, experiments and development of the methodologies will be provided along with all relevant experimental data. Part I: The [alpha]-amino carbonyl moiety has great potential for being a very useful synthetic intermediate for the incorporation of nitrogen owing to the synthetic utility and versatility of the carbonyl functional group. Despite this potential the synthesis has long been problematic owing to their tendency to undergo condensation reactions. We aimed to synthesize them utilizing a protected carbonyl in the form of a triisopropylsilyl enol ether and an electrophilic nitrogen source that could incorporate the nitrogen via an ene-[2,3] sigmatropic reaction sequence. To this end we used an N-sulfinyl carbamate as an electrophilic source of nitrogen that could be utilized for a regiospecific allylic amination of alkenes or could be used to form a highly reactive sulfur diimide that could be used for the allylic amination of alkenes or silyl enol ethers. Part II: Many pharmacologically important and synthetically interesting alkaloids have been formed in nature by the o,p oxidative phenolic coupling of various benzyl-tetrahydroisoquinoline alkaloids. One major class of alkaloids derived from this generalized oxidation is the proaporphine alkaloids and they possess an acid labile spirocyclic-dienone system obtained from this coupling. These compounds have great potential for being used for their anesthetic properties. Despite the relative ease of synthesizing the benzylisoquinoline alkaloids the application of the biomimetic oxidative coupling to make the quaternary center of these compounds gives very poor yields. We opted to form this spiro-dienone system by using a two step Suzuki coupling-para phenolate alkylation methodology that had been used to synthesize the related alkaloids codeine and narwedeine. In doing this we opted to extend the practical application of this methodology by the displacement of an alcohol derived leaving group. / text

Polycarbonates are found in a variety of common products in daily life due to their favorable mechanical and electrical properties. In addition, they are widely used in biomedical areas due to their stability and biological inertness. Therefore, the production of polycarbonates became an important industrial process in the past decades. However, the current industrial process usually requires toxic phosgene gas as a starting material. Thus, the environmentally benign route by using metal catalyzed couplings of epoxides and CO_(2) to produce polycarbonates has received attention from researchers. In this dissertation, metal catalyzed CO_(2)/cyclic ether copolymerization, depolymerization of polycarbonates, and the equilibria between polycarbonate and corresponding six-membered cyclic carbonate will be investigated. First, the Co(III) catalyzed copolymerizations of CO_(2) and various epoxides with electron-withdrawing substituents to afford polycarbonates are examined. Comparative kinetic studies were performed via in situ infrared measurements as a function of temperature to assess the activation barriers for the production of cyclic carbonate versus copolymer involving electronically different epoxides: styrene oxide, epichlorohydrin, and propylene oxide. Thermodynamically stable cyclic carbonate byproducts are produced during the course of the reaction from the degradations of propagating polymer chains. The depolymerization reactions of several polycarbonates produced from the completely alternating copolymerization of styrene oxide, epichlorohydrin, propylene oxide, cyclohexene oxide, indene oxide, and cyclopentene oxide with carbon dioxide have been investigated. Various reaction pathways can be found under different reaction conditions, including process involving chain-end backbiting and radical intermediates. Temperature-dependent kinetic studies have provided energy of activation barriers for cyclic carbonate formation. In addition, the generated monomeric materials from the degradation of select polycarbonates show the possibility of chemical recycling of plastic waste. For the copolymers made from CO_(2) and oxetane derivatives, this study focuses on the influence of steric hindrance in the 3-position of the monomer oxetane. The (salen)CrCl/onium salt catalyzed coupling reactions of these oxetane derivatives and carbon dioxide are reported. Depolymerizations of copolymers to their corresponding cyclic carbonates were also studied. In addition, several six-membered cyclic carbonates were synthesized to examine their equilibria between monomeric cyclic carbonates and their corresponding polycarbonates.

No description available.

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants that are recognized as global environmental contaminants and a potential health risk. They have been shown to elicit neurodevelopmental toxicity through disruption of the cholinergic neurotransmitter system in rodent models, but the effects of environmentally relevant exposures in wildlife species are unknown. The objective of this study was to assess the effects of the commercial pentabrominated diphenyl ether mixture DE-71 on cholinergic parameters in captive mink (Mustela vison) following dietary exposure of adult females and in utero, lactational and dietary exposure of their offspring. Adult females were fed diets containing 0, 0.1, 0.5 or 2.5 μg/g DE-71 from four weeks prior to breeding through weaning of their kits at six weeks of age. A portion of the weaned kits were maintained on their respective diets through 27 weeks of age. Cholinergic neurochemical biomarkers, including muscarinic acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (mAChR) binding, cholinesterase (ChE) activity and acetylcholine (ACh) concentration, were assayed in the cerebral cortex, and ChE activity measured in the plasma. Results indicated no significant effects of DE-71 on cholinergic parameters in the cerebral cortex, but a 3-fold increase in ChE activity in the plasma of adult females in the 2.5 μg/g DE-71 group. There were also no direct effects of DE-71 on mAChR or mAChR binding or ChE activity in the enzyme and receptor fractions from the whole brain of untreated mink following in vitro exposure to 0-23.6 nM DE-71. This study demonstrated that environmentally relevant exposures to DE-71 did not affect key parameters of the cholinergic neurotransmitter system in the brain of captive mink.

Thesis (Ph. D.)--Michigan State University. Dept. of Sociology, 2008. / Title from PDF t.p. (viewed on Apr. 16, 2009) Includes bibliographical references (p. 173-198). Also issued in print.

Title from title page of PDF (University of Missouri--St. Louis, viewed March 22, 2010). Non-Latin script record Includes bibliographical references.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: zeolite adsorption, TBA, tert butyl alcohol, wastewater remediation. Includes bibliographical references (leaves 60-62 ).

Thesis (Ph. D.)--University of Michigan, 1954. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 127-130).

No description available.