Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. Albert E. Stiegman, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed June 8, 2005). Document formatted into pages; contains xiii, 79 pages. Includes bibliographical references.

Th.--Sci.--Aix-Marseille 2, 1981.

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No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Mercury (II) and lead (II) ions, but not mercury (l) and thallium (I), react with both the nitrosyIdisulphonate, ON(S03)22- and the hydroxylaminedisulphonate dianions, ON(S03)22−-, to yield the corresponding metal sulphate and a mixture of sulphate and sulphite ions. Silver (I) ions are reduced to the metal by both anions, but reacts with potassium imidodisulphonate, HN(SO3K)2, and tripotassium imidodisulphonate, KN(S03K)2, to yield trisilver imidodisulphonate, Ag3NS2O6, and disilver potassium imidodisulphonate, Ag2KNS2O6. The reaction of some related salts are also reported. Mechanisms for some of the decompositions, and stoichiometric equations are proposed. No metal salts of hydroxylaminedisulphonates, HON(SO3M)2 were isolated. The silver imidodisulphonate salts failed to react with both alkyl and aryl halides. A series of N, N-bis-(arylsulphonyl)hydroxylamines, (p-XC6H4S2)2N0, were synthesised (X = H, Me, MeO, Cl and F). The species (p-XC6H4S2)2N0, p-XC6H4S2NO and p-XC6H4S2 are proposed as intermediates during the oxidation of the bis-species with PbO2, silver (I,III) oxide, AgO, MnO2. Pb(O2CMe)4 or nitric acid to N, N, 0-tris-(arylsulphonyl)hydroxylamines, p-XC6H4S2)2N0S2C6H4X-p and nitrate ion. A mechanism involving hydroxylamine is ruled out. I. r. and n.m.r. spectra show that the tris-species are hydroxylamines, R2NOR, rather than amine oxides, R3NO, and the structure is considered by a comparison with (CF208)2NOH and (CF3)2NO. The e.s.r. spectra of the tris-species in benzene indicates the presence of a nitroxide radical. The bis-species are found to decompose to the tris-hydroxylamine and the corresponding arenesulphonic acid, while the tris-species decompose to the sulphonic acid. Oligomerisation of cyclohexene is observed during the oxidation of bis-hydroxylamines, while with bases, such as pyridine, the hydroxylamine is converted to a mixture of (RSO2)2NH pyridine-N-oxide and a pyridinium arylsulphonate. N, N, 0-tris-(Alkyl-sulphonyl) hydroxylamines could not be isolated. Nitrosylarene-sulphinates, p-XC6H4SO2NO are proposed as intermediates but could not be isolated from the reactions of nitrosyl chloride and nitrogen (II) oxide with arylsulphonylhydroxylamines. p-XC6H4SO2NHOH, (p-XC6H4SO2)2NOH and p-XC6H4SO2NH2 (X=H, CH3) are all are converted by NOCl to p-XC6H4SO2Cl, but (p-XC6H4S02)2N0S02C6H4X-p and (p-XC6H4SO2)2NH are unaffected. Oxidation of C6H5SO2NHOH by a range of oxidants yielded, C6H5SO2Cl, C6H5SO3H, or (C6H5SO2)2NOSO2C6H5, but not C6H5SO2NO. Diene cycloaddition products of p-XC6H4SO2NO could not be isolated. p-CH3C6H4SO2Na is converted by nitrosyl chloride to p-CH3C6H4SO2Cl rather than to p-CH3C6H4SO2NO. (p-CH3C6H4SO2)2NH is inert to a wide range of oxidants. Both (p-XC6H4S02)2NOH and (p-XC6H4S02)2N0S02C6H4X-p initiate free-radical halogenation by dichlorine and dibromine, but not by diiodine, of benzene and cyclohexane. Simple carboxyamides also initiate free-radical chlorination of the same substrates. (N-aryl-N-arylsulphonyl) hydroxylamines were oxidised by PbO2 and Pb(02CMe)4, but not MnO2, to a mixture of the corresponding [N- aryl-N, O -bis(aryl sulphonyl)]hydroxylamine, nitrobenzene and azoxybenzene. The tris-species appears to contain the nitroxide radical, ArS02N(0)Ar1. A similar mechanism to that for the oxidation of (p-XC6H4S02)2N0H is proposed.

The electrochemical hydroxylation of aromatic substrates was investigated in some detail, with the view to develop a method, which could produce dihydroxybenzenes in acceptable yields. Of particular interest was the selectivity and yield of the 1,4-dihydroxybenzenes. Two distinctly different methods were investigated in order to achieve this goal, acyloxylation and direct electrochemical hydroxylation. Acyloxylation is the process where radical cations generated at the anode undergoes nucleophilic attack by acetate anions. The resulting aromatic acetates so produced can then be hydrolysed to the phenolic compounds. Two nucleophile systems were considered in the investigation, acetates (acetoxylation) and trifluoro-acetates (trifluoro-acetoxylation). These investigations were conducted under a variety of conditions using phenol and phenyl acetate as starting materials. From the results it was, however, concluded that the acetoxylation of these aromatic compounds occurs in unacceptable product and current yields. Trifluoro-acetoxylation on the other hand showed promise, but due to the nature and cost of the reagents it was deemed to be an impractical process. Direct electrochemical hydroxylation: in which the radical cations produced at the anode undergoes nucleophilic attack by water producing the corresponding dihydroxybenzenes. These dihydroxybenzenes are then further oxidised to the benzoquinones, which then undergo reduction at the cathode in order to produce the corresponding dihydroxybenzene. In this process phenol, 2-tert-butylphenol and 2,6-di-tert-butylphenol were investigated as substrates. The results indicated that the yield towards the 1,4-dihdroxybenzenes increased as the degree of substitution on the ring increased.

No description available.

N-hydroxylating monooxygenases (NMOs) are Class B flavin-dependent monooxygenases found only in fungi and bacteria. These enzymes catalyze the hydroxylation of nucleophilic primary amines, such as those found in histamine, L-ornithine, L-lysine, and small aliphatic diamines. The hydroxamate moiety produced by this reaction is key for the production of siderophores, small chelating compounds that allow survival in iron limiting conditions. NMOs involved in siderophore biosynthesis have been shown to be essential for pathogenesis in organisms such as Aspergillus fumigatus, Pseudomonas aeruginosa, and Mycobacterium tuberculosis. Therefore, NMOs are considered novel drug targets for the treatment associated with these diseases. Herein we present the characterization of TheA, an NMO from Thermocrispum agreste. The enzyme mechanism was studied using steady state kinetic measurements, thermostability, and stopped flow spectrophotometry assays. Using these techniques, the catalytic rates, substrate binding affinities, thermal stability, and coenzyme specificities were determined. Additionally, NADPH analogues were produced to use as tools to study FAD reduction in NMOs. An unspecific reduction reaction of NADP+ using NaB2H4 yielded [6-2H]-NADPH, [2-2H]-NADPH, and [4-2H]-NADPH. Compound identity was confirmed by mass spectrometry and unidimensional proton nuclear magnetic resonance (NMR). Results presented in this thesis lay the foundation for future studies of NMOs using NADPH analogues. In conjunction, these results will improve the general knowledge and understanding of flavoenzymes, ornithine monooxygenases, and their associated mechanisms. / Master of Science in Life Sciences