Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 11, 2008) Includes bibliographical references.

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Diels-Alder polyphenylenes (DAPPs) are chemically and thermally stable polymers, used for dielectric resins, gas separation membranes, and fuel cell proton exchange membranes. Highly fluorinated DAPPs are expected to have better thermal stability and chemical resistance, higher glass transition temperatures, improved compatibility with other fluorinated polymers (like NafionTM), and better adhesion to certain surfaces such as some metals. This thesis proposes a synthesis of highly fluorinated DAPPs by reacting novel, fluorinated bis-cyclopentadienone (CPD) monomers with known aromatic dialkynes. This thesis starts with an introduction to DAPP synthesis, properties, and applications. The second chapter focuses on the synthesis of 4,4′-bis[1,2,4-tris(perfluoro-4-tolyl)cyclopentadien-5-one-3-yl]octafluorobiphenyl (CPD monomer). In the first step, disodiumbis(cyclopentadieny)octafluorobiphenyl was combined with 6 equivalents of octafluorotoluene in HMPA to give 4,4′-bis[1,2,4-tris(perfluoro-4-tolyl)cyclopentadiene-3-yl]octafluorobiphenyl. Oxidation to the corresponding diketone was effected using selenium dioxide. The synthesis of CPD monomer presented several unexpected challenges that were ultimately overcome. The third chapter describes a series of initial polymerization experiments as well as some model reactions that were carried out to understand monomer reactivity. Finally the future research plan of synthesizing different polymers by Diels-Alder reaction and nucleophilic substitution reaction has been discussed. / Master of Science

<p>This thesis deals with the peroxyoxalate chemiluminescence (POCL) reaction and its application as a detection technique in flow systems for chemical analysis. Particularly, miniaturized flow systems aimed for separation of molecules. In such systems, a high light intensity and a rapid development of the emission are the desired reaction characteristics, for reasons discussed in this text. The work tries to develop an understanding of the chemical processes involved in POCL, with special emphasis to the species favoring or hindering a rapid light evolution. Hence, is the focus placed on the nature of catalysis and the desired properties of substances acting as catalysts in this reaction. Consequently, the scientific papers on which this work is founded includes both systematic stopped-flow studies of catalyst candidates and of the causes for diminished light emission. In addition, multivariate strategies for reaction optimization in practical analysis situations are treated, and the application of the POCL technique to detection of serum-extracted neuroactive steroids, derivatized with fluorescent moieties, is presented.</p><p>From the experiments in this thesis it is clear nucleophilic catalysts are the most efficient enhancing compounds, which means that they must possess a carefully balanced characteristics of nucleophilicity, leaving group ability, and basicity. The investigations also conclude that the feature of basicity efficiently can be delegated to a non-nucleophilic co-catalyst, which allow the use of nucleophilic catalysts that need to be deprotonated to be active. This thesis also shows the importance of minimizing the amount of competing nucleophiles at the site of reaction to maintain the emission. This implies that also solvents and buffer substances should be carefully chosen not to interfere with the emission process.</p><p>The most promising combination of catalysts found in this work was 4,5- dichloroimidazole together with 1,2,2,6,6-pentamethylpiperidne. This arrangement was capable of speeding the reaction more than tenfold while increasing the maximum emission intensity by about the same factor.</p>

This thesis deals with the peroxyoxalate chemiluminescence (POCL) reaction and its application as a detection technique in flow systems for chemical analysis. Particularly, miniaturized flow systems aimed for separation of molecules. In such systems, a high light intensity and a rapid development of the emission are the desired reaction characteristics, for reasons discussed in this text. The work tries to develop an understanding of the chemical processes involved in POCL, with special emphasis to the species favoring or hindering a rapid light evolution. Hence, is the focus placed on the nature of catalysis and the desired properties of substances acting as catalysts in this reaction. Consequently, the scientific papers on which this work is founded includes both systematic stopped-flow studies of catalyst candidates and of the causes for diminished light emission. In addition, multivariate strategies for reaction optimization in practical analysis situations are treated, and the application of the POCL technique to detection of serum-extracted neuroactive steroids, derivatized with fluorescent moieties, is presented. From the experiments in this thesis it is clear nucleophilic catalysts are the most efficient enhancing compounds, which means that they must possess a carefully balanced characteristics of nucleophilicity, leaving group ability, and basicity. The investigations also conclude that the feature of basicity efficiently can be delegated to a non-nucleophilic co-catalyst, which allow the use of nucleophilic catalysts that need to be deprotonated to be active. This thesis also shows the importance of minimizing the amount of competing nucleophiles at the site of reaction to maintain the emission. This implies that also solvents and buffer substances should be carefully chosen not to interfere with the emission process. The most promising combination of catalysts found in this work was 4,5- dichloroimidazole together with 1,2,2,6,6-pentamethylpiperidne. This arrangement was capable of speeding the reaction more than tenfold while increasing the maximum emission intensity by about the same factor.

Activated cyclopropanes have been extensively used in synthetic chemistry as precursors for cycloaddition reactions. The rationale behind this is their ability to undergo ring-opening when activated by a Lewis acid, this can be enhanced further by the presence of a carbocation stabilising group like electron-rich aromatics. The stabilised dipole formed after ring opening can be trapped with suitable electrophiles such as imines and aldehydes via a [3+2] cycloaddition reaction. This results in the synthesis of pyrrolidines and tetrahydrofurans in excellent yields but moderate diastereoselectivity. Similarly, 6-membered heterocycles can be formed via a [3+3] cycloaddition reaction of activated cyclopropanes with nitrones. Now to extend the scope of the methodology, a [3+3] dipolar cycloaddition has been developed using activated 2,3 disubstituted cyclopropane diesters to access a range of highly functionalised oxazines in moderate to good yields (50-75%) and with reasonable diastereoselectivity. The use of activated symmetrical disubstituted cyclopropanes afforded the desired oxazines in a regio- and diastereocontrolled manner, while the use of unsymmetrical cyclopropanes significantly reduced the diastereoselectivity of the reaction. The stereochemistry outcome of the reaction developed was determined by nOe analyses and X-ray diffraction structures could be recorded in some examples. A new methodology has also been developed to gain access to novel N-heterocyclic- and phenol- substituted cyclopropanes in one step from the corresponding cyclopropene via a conjugated addition.

The second order rate constants for nucleophilic substitution by methoxide of (Z)- and (E)-O-methylbenzohydroximoyl fluorides [C6H4C(F)=NOCH3] with various substituents on the phenyl ring [p-OCH3 (1h, 2h), p-CH3 (1g, 2g), p-Cl (1f, 2f), p-H (1e, 2e), (3,5)-bis-CF3 (1i, 2i)] in 90:10 DMSO:MeOH have been measured. A Hammett plot of these rate constants vs σ values gave positive ρ values of 2.95 (Z isomer) and 3.29 (E isomer). Comparison of these rates with methoxide substitution rates for Omethylbenzohydroximoyl bromide [C6H4C(Br)=NOCH3] and Omethylbenzohydroximoyl chloride [C6H4C(Cl)=NOCH3] reveal an element effect for the Z isomers of Br:Cl:F(1e) = 2.21:1.00:79.7 and for the E isomers of Cl:F(2e) = 1.00:18.3. With the p-OCH3-imidoyl halides the following element effects are found: Br:Cl:F(1h) = 2.78:1.00:73.1 for the Z isomer and Br:Cl:F(2h) = 1.97:1.00:12.1 for the E isomer. Measurement of activation parameters revealed ∆S≠ = -17 eu for 1e and ∆S≠ = -9.9 eu for 2e. Ab initio calculations (HF/6-31+G*, MP2/6-31+G*//HF/6-31+G*, B3LYP/6- 31+G*//HF/6-31+G*, HF-SCIPCM/6-31+G*//HF/6-31+G*) were performed to define the reaction surface. These calculations demonstrate a relatively large barrier for nucleophilic attack in relation to halogen loss and support the experimental findings that this reaction proceeds by an addition-elimination mechanism (AN# + DN). The imidoyl fluorides have been used to synthesize highly functionalized O-methyloximes by reaction with enolate anions derived from malononitrile, ethyl cyanoacetate, and diethyl malonate. Acid-catalyzed isomerization of compounds containing the O-methyloxime moiety have been investigated with ab initio calculations (HF/6-31+G*, MP2/6- 31+G*//HF/6-31+G*, B3LYP/6-31+G*//HF/6-31+G*). Barriers for rotation around the C-N bond following protonation have been calculated. The calculated barriers are discussed in relation to an isomerization mechanism of protonation-rotation versus a nucleophilic catalysis.

Molecules of anthocyanins and quinones possess distinctive electrophilic character, which is demonstrated by their facile reactions with nucleophiles such as sulfite, thiols, amines and water. In food systems, one of their likely targets would be nucleophilic centers in the side chains of amino acids. Our experiments revealed that on a short-term exposure (1 72 h) to free amino acids in solutions with pH < 7 glycosides of cyanidin and quinones of phenolic acids did not yield nucleophilic addition products with most of the amino acids. A notable exception was cysteine, which reacted with oxidized phenolic acids and caused anthocyanin bleaching at elevated temperature. Thermodynamic aspects of the nucleophilic addition reactions were investigated with the aid of computational chemistry. We have also found that enzymatic browning in apricot puree does not lead to trans-cis -carotene isomerization, contrary to some previous reports. Increased availability of -carotene for extraction was recorded for browned apple- and pear-apricot purees in comparison with the non-browned purees. / Food Science and Technology

1. The key glutarimides were obtained via facile [3+3] annulation. The method featured regioselective introduction of C-6 substituents in glutarimides, and application to the synthesis of natural products and pharmaceuticals. 2. The synthesis of a novel substituted aza-ticyclic compounds through the use of the intramolecular Diels-Alder reaction is present. Further aromaticzation in the present of BF3 to afford 2,3-dihydro-isoindolone.The use of method for the rapid preparation of a substituted isoindolone framework is described.

1. A new route towards the synthesis of drugs and alkaloids by using N-alkylsulfonylacetamide and unsaturated ester as starting materials via stepwise [3+3] annulation. 2. The application of regioselective nucleophilic addition of glutarimide which prepared via stepwise [3+3] annulation. 3. Synthesis of (E)-3-Substituted-N-Alkylacryl-amides and 3,4-Disubstituted Succinimides by using N-alkylsulfonyl-acetamide and alkyl halides as starting materials in the different reaction condition.