Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. Includes bibliographical references (leaves 124-138).

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On-line HPLC/Spectrofluorometric techniques have been applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in coal-derived products. The PAHs were isolated by preparative silica gel columns with a hexane mobile phase, and fractionated into five samples based on the number of condensed rings. Each fraction was separated by reverse phase HPLC with an acetonitrile/water mobile phase. Compounds were detected by means of on-line fluorescence detection. Naphthalene, pyrene, fluoranthene, benzo(a)anthracene and benzo(a)pyrene were verified by comparing the excitation and emission spectra obtained by a stop-flow technique with those of PAH standards. A Picramido bonded phase packing was prepared by the reaction of picryl chloride and amino bonded phase silica gel, forming a charge-transfer active phase. The retention mechanism of aromatic hydrocarbons on the picramido bonded phase column was studied in three ways: electronic effects (Hammett cr function); temperature effects on heats of adsorption and solvent effects on capacity factors. Chromatographic properties of the picramido bonded phase column were compared to those of silica gel and amino bonded phase columns. An on-line LC/LC column switching system was developed for PAH analysis of solvent refined coal (SRC). It utilized a guard column, an amino bonded phase, and a picramido bonded phase column. The guard column prevented the highly polar materials from entering the analytical columns; the amino bonded phase column separated PAH materials into groups based on an adsorption mechanism; the picramido bonded phase column separated PAHs based on charge-transfer mechanism, and provided better resolution. / Ph. D.

The structures of Diels-Alder cycloaddition of cyclopentadiene to 2,6-dimethyl-p-benzoquinone and methylcyclopentadiene to 2,6-dimethyl-p-benzoquinone were assigned by analysis of 1-D and 2-D proton and carbon-13 NMR spectra. The structures of the cycloadduct of methylcyclopentadiene to 2,6-dimethyl-p-benzoquinone and that of the corresponding intramolecular [2+2] photocyclization product were also obtained by single crystal X-ray structural analysis. As the second part of the study, a new polycyclic "cage" molecule, a substituted trishomocubane isomer, was synthesized. In this synthesis, reductive bond cleavage followed by Dieckmann condensation was employed. Wolff-Kishner reduction then was used to convert a β-keto ester "cage" molecule to the corresponding carboxylic acid. A compound that possesses twofold symmetry was isolated from reaction product mixture. The structure of this compound has been established by single crystal X-ray crystallography.

The objective of this study was to explore intramolecular ketene cycloadditions with the anticipated results of developing new synthetic methodology for the synthesis of polycyclic compounds difficult to obtain by other procedures. (o-Alkenylphenoxy)ketenes were initially selected for this study because these ketenes provided a favorable proximity for the intramolecular [2+2] cycloaddition reactions. The difunctional precursors, (o-alkenylphenoxy)- acetic acids, were readily prepared from o-alkenylphenols and ∝-halocarboxylic acids and were converted to the corresponding acid chlorides by reaction with oxalyl chloride. The acid chlorides were dehydrochlorinated to the corresponding (o-alkenylphenoxy)ketenes by treatment with triethylamine. The ketenes undergo a facile intramolecular [2+2] cycloaddition to give polycyclic eye 1obutanones. The (o-vinylphenoxy)ketenes are clearly more reactive than the (o-allylphenoxy)ketenes and provide much better yields of the cycloaddition products because of electronic effects in the transition state in the cycloaddition process. The intramolecular [2+2] cycloadditions of keteniminium salts were included in this study as a more electrophilic alternative to ketenes that will react with less nucleophilic carbon-carbon double bonds. However, the use of keteniminium salts instead of ketenes in Intramolecular cycloadditions does have some limitations. The synthesis of benzofurans via the intramolecular [2+2] cycloadditions of (o-acylphenoxy)ketenes was accomplished. The initially formed ß-lactone cycloaddition products spontaneously underwent decarboxylation to the benzofurans. The aromaticity of the benzofurans is apparently a very strong driving force for the cycloaddition. During the course of this study, two new synthetic methods were discovered which in many instances represent a significant Improvement over existing methods. The Wittig Reactions of ketoacids without protecting the carboxyl groups provide a reliable source of the precursor unsaturated acids needed for intramolecular ketene-olefin cycloadditions. Also, the one-pot preparation of intramolecular ketene cycloaddition products from the carboxylic acid via the tosylate represents a new synthetic method. This procedure eliminates the acid halide preparation, isolation and purification step, thereby significantly simplifying the synthesis.

As part of a continuing study of the synthesis and chemistry of new, substituted pentacyclo(5.4.0.0²，⁶.0³，¹º.0⁵，⁹)undecanes, the following compounds have been synthesized: 1: X=O, Y=SiMe_3; 2: X=CH_2, Y=SiMe_3; 3: X=O, Y=Cl; 6: X=OAc, Y=H; 8: X=OC(O)Ph, Y=H; 9: X=OSO_2Ph, Y=H; 11: X=OH, Y=H; 12: X=OMe, Y=H; 14: X=CHSiMe_3, Y=SiMe_3; 15: X=OH, Y=Cl; 16: X=OAc, Y=Cl; 17: X=OMe, Y=Cl. An important objective of this work is to prepare new polycyclic cage compounds which can be utilized as intermediates for the synthesis of new, substituted tricyclopentanoid natural products (triquinanes) and related systems. Compounds 1-4 were identified as target molecules in this connection.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

The increased use of residential wood and coal stoves in recent years h.as caused a growing concern for polycyclic aromatic hydrocarbon (PAH) emissions from these stoves. Design of stoves that reduce PAH emissions has been hampered because existing PAH measurement techniques are slow, complex, and expensive. This study investigates two simple, inexpensive, real-time PAH measurement techniques which might be suitable for testing stoves. The first uses a device, called the "moving tape sampler" (MTS), that collects particulate samples on filter paper tape and uses sensitized flourescence to measure total PAH on the tape. The MTS results are compared to the results of a conventional PAH measurement technique, but no definite relationship between the two is found. Uncertainties about the conventional technique make it unclear whether one or both of the techniques give incorrect emission rates. The second method is the use of CO and NO_x as proxy compounds to infer PAH emissions. A plot of CO emission factors against PAH emission factors suggest CO as a proxy for PAH emissions while a similar plot for NO_x gives some evidence of NO_x being an "inverse" proxy for PAH emissions. The lack of a trusted PAH measurement technique has hampered the evaluation of both the MTS and proxy techniques. / Master of Science

Many benz(a)anthracene derivatives are able to produce cancer in the experimental animal. There is a correlation between the calculated total electronic charge of the K-region and this carcinogenic activity. There is also ample proof that benz(a)anthracene derivatives are honed to the skin through quinoid type bonds in the K"region. However, the prediction of physiological activity of benz(a)anthracenes is still unreliable because of the limitations of the theoretical model described by existing theories. The purpose of this work was to synthesize some substituted benz(a)anthracenes with a shielded K-region and with a different L-region electron density than in 7-phenyl-bena(a)anthracene in the hope of increasing our knowledge regarding molecular structure-physiological relationship. / Ph. D.