The synthesis of the sulfur homocycles S6, S9, S10, S12 and S20, which belong to the group of sulfur allotropes, has been achieved based on existing procedures. Polymeric sulfur Smu was also prepared. / The parameters of a small scale model reaction between 2,3-diphenyl-1,3-butadiene and S10 were optimized. Products were identified and 1H-NMR yields were calculated by comparison with an internal standard. The experimental parameters of this model served as a base for further reactions of S 10 with a variety of simple or conjugated olefins. The products of these reactions were fully isolated and characterized using standard spectroscopic techniques. The structures of a new bis-sulfurated compound having a norbornane framework and of the product obtained from the dimerization of norborn-5-ene-2,3-dithiol were also confirmed by single crystal X-ray crystallography. / The sulfur homocycles S9, S12 and S20 were also found to react with norbornene and two different 1,3-dienes. Products were identified and 1H-NMR yields for these small scale reactions were calculated by internal standard comparison. Differences and similarities with the products obtained with S10 are discussed. Sulfuration efficiencies of the different allotropes towards selected substrates are also compared. / A mechanistic study was carried out. The implication of sulfur radicals in the thermal decomposition of S10 has been suggested. Reaction mechanisms accounting for the formation of the different products observed are proposed.

The use of polar solvents as activators in the sulfuration of dienes has been demonstrated. A mechanism of sulfuration with activated sulfur under these conditions was investigated. The identity of sulfur species involved in sulfuration was determined. The modeling of activated sulfur with various metallocene polysulfide catalysts in nonpolar solvents was also examined. The specifics of the metallocene polysulfide catalytic system were studied in detail. / The most efficient catalyst in the sulfuration of dienes, molybdocene tetrasulfide, became an object of oxidative studies. These studies were extended to molybdocene disulfide and tungstenocene tetrasulfide. The main products of the oxidation of metallocene tetrasulfides, 1-oxides, were thermally unstable and at room temperature rearranged to corresponding 2-oxides. The mechanism and factors controlling this rearrangement were investigated. / Oxidations of molybdocene tetrasulfide with excess of oxidant were also carried out. The unstable intermediates were identified. The rearrangement of highly oxidized molybdocene tetrasulfide 1,1,4,4-tetroxide yielding the intriguing ionic molybdocene disulfide dimer, was examined. Properties of the dimer, with emphasis on the deprotonation, were described. / Molybdocene disulfide and its oxide were treated separately with SO 2, H2S and finally with a mixture of both gases to evaluate the potential catalytic activity in the Claus process. The formation of two products resulting from the novel insertion of SO2 into the S-S bond, molybdocene trisulfide 2,2-dioxide and molybdocene bis(O-alkylthiosulfate) was observed. Both molybdocene disulfide and disulfide oxide reacted with the mixture of SO2 and H2S stoichiometrically. The reason for the lack of catalysis was discussed.

In order to develop a novel analog of the antitumour agent Mitozolomide 1, the diazotization of a variety of N-(2-aminophenyl)-N$ sp prime$-alkylureas was studied. The diazotization of N-(2-aminophenyl)-N-alkylureas of type 2a gave benzotriazole derivatives 3 (R=CONHalkyl). However, that of N-methyl-N-(2-aminophenyl)-N-alkylureas 2b gave 1,2,3,5-benzotetrazepinones 4 after the neutralization of the reaction mixture. This finding allowed the synthesis of bi- and tricyclic tetrazepinones. Electronic effects on the stability of the tetrazepinone ring system were studied by varying substituents at the benzene moiety. The stability of the tetrazepinones increased with increasing electron withdrawing character of the substituent. Variation of substituents at N5 showed that their stability decreases with increasing steric bulk of the substituents. The decomposition of benzotetrazepinones generally gave N-phenyl-N,N$ sp prime$-dimethylureas, 1-alkylbenzotriazoles and 2-hydroxy-benzimidazoles. The synthesis of stable pyrido-1,2,3,5-tetrazepinones is also described. The tetrazepinones were generally characterized by $ sp1$H and $ sp{13}$C NMR, X-ray diffraction, mass spectroscopy and microanalysis. The existence of the triazene chain was usually confirmed by $ sp{15}$N NMR spectroscopy after specific labelling of the central nitrogen (N2).(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)

Thymidine dimers 16 and 18, connected by amide or N-methylamide linkages, have been prepared. The dimers were incorporated into normal strands of DNA by solid phase synthesis. Thermal denaturation studies, using complementary single-stranded RNA, indicated that these modifications caused no destabilization of the DNA-RNA duplex. / The block synthesis of amide-linked homotetramer 30 is described. The synthesis of the corresponding octamer could not be verified because of lack of solubility. One by one homologation was found to be a suitable method for the preparation of N-methylamide analogues. / Poly(ethylene glycol), covalently attached to the 3$ sp prime$ or 5$ sp prime$ end of amide-backbone thymidine homopolymers, was found to greatly increase their solubility. The poly(ethylene glycol) simultaneously served as a soluble solid support for the homologation reactions.$ sp*$ ftn$ sp*$Please refer to the dissertation for diagram.

The diastereoselective synthesis of phosphite triesters and related phosphorothioate triesters and diesters has been investigated, with the goal of synthesizing diastereomerically pure DNA phosphorothioates. / Towards this end, the elaboration of a new heterobicyclic structure, imidazo-oxazaphosphorine such as 56, is reported. This unstable intermediate led to the highly diastereoselective synthesis of simple phosphite triesters upon reaction with various alcohols. / Two new types of sterically hindered chiral oxazaphosphorinanes 135 and 146 were then synthesized from cholesterol and camphor respectively. These structures, derived from $ gamma$-aminoalcohols possessing a tertiary alcohol function, could be isolated and characterized. They revealed very reactive in acidic conditions and led to rearrangements. / Finally, oxazaphosphorinane 188 derived from 1,2-O-isopropylidene-D-xylofuranose, was synthesized and characterized. The introduction of a participating group adjacent to the leaving phosphorothioate group led to the fast release of the phosphorothioate moiety. This new chiral auxiliary was successfully used as a precursor in the diastereoselective synthesis of a T-T phosphorothioate dimer, in a diastereomeric ratio of 28.5:1.* ftn*Please refer to dissertation for diagrams.

<p> A systematic study of how various reaction parameters affect the product distribution of gas-solid reactions was carried out in a new reactor of local design. These reactions involve the trifluoromethylation of C₆₀, C₇₀, and the endohedral metallofullerenes Sc₃N@C₈₀ and Y₃N@C₈₀; and in particular, the reactions were optimized to favor C₆₀(CF₃)₂ and C₆₀(CF₃)₄. A new solution phase homogeneous perfluoroalkylation method was used to prepare a series of 1,7-C₆₀(R_F)₂ compounds with different R_F chain lengths and branching patterns. A range of analytical methods including ¹⁹F NMR and UV-vis spectroscopy, APCI mass spectrometry, and X-ray crystallography were used to structurally characterize the compounds. Cyclic voltammetry, DFT <i> E</i>(LUMO) calculations, and gas phase electron affinity (EA) measurements were used to determine the substituent effect of the R_F groups. The results conclusively showed that the solution phase <i>E</i>_1/2, calculated <i>E</i>(LUMO), and EA values&mdash; that are typically assumed to be correlated for a series of electron acceptors&mdash; are not always correlated. Several highly efficient and selective methods were developed for the further functionalization of selected trifluoromethyl fullerenes (TMFs). These new functionalized TMFs were structurally characterized using the aforementioned analytical techniques and the X-ray crystal structures of five new derivatized TMFs were determined. Analysis of the how these newly derivatized TMFs pack in a crystalline solid revealed fullerene density values that were in general twice that of reported fullerenes that pack in the same motifs. These derivatized TMFs also exhibited extended networks of short C&dot;&dot;&dot;C distances between fullerene cages of adjacent molecules that has been correlated to increased free charge carrier motilities in organic photovoltaic device active layers. The solution phase E_1/2 values of the most commonly used fullerene derivatives in OPV devices were measured under carefully controlled conditions and revealed that poor reporting of electrochemical conditions, mistakes interpreting electrochemical data, and fullerene impurities have combined to cause significant confusion about the reported electrochemical values in the literature. A preliminary study of 32 OPV devices fabricated with active layers containing perfluoroalkylfullerenes (PFAFs) indicated that (i) PFAFs can function as suitable electron acceptors in OPVs, and (ii) that a more detailed study examining the complex electronic interplay between the fullerene electron acceptor and polymer donor is warranted.</p>

This thesis is about the development of new methods to introduce functionalities directly to compounds with a secondary nitrogen atom via C-H bond oxidation. / A copper-mediated oxidative coupling between glycine derivatives (including short peptides) and nucleophiles (including malonates, aryl alkynes, arylboronic acids and indoles) were developed. Later, a chiral chlorosilane induced asymmetric indolation of imino amides was also studied. In addition, a study on the α-arylation of tetrahydroisoquinoline with iodobenzene was presented. The reaction was proposed to undergo via palladium catalyzed β-hydride elimination, imine insertion pathway. / This thesis also described a three-component coupling reaction of aldehyde, alkyne and alkyl hydroxylamine catalyzed by CuCl/bipy complex to synthesize β-lactam was presented. / In the end of the thesis, a collaboration work with the Department of Biochemistry on the study of thioxothiazolidinone derivatives as the cellular inhibitor of protein tyrosine phosphatase 1B was presented. The thioxothiazolidinone derivatives were synthesized and the bioactivities were studied. / Cette thèse a pour sujet le développement de nouvelles méthodes pour la fonctionnalisation directe de composés possédant des amines secondaires via l'oxydation de liaisons C-H. / Dans la première partie de cette thèse, un couplage oxydant au cuivre entre des dérivés de la glycine (incluant des peptides de petite taille) et des nucléophiles est présenté. L'indolisation asymétrique d'amides aminés induit par une silicone chlorée est également étudiée. Cette partie se termine par une étude de l'arylation-alpha de la tetrahydroisoquinoline avec de l'iodobenzène. Une voie mécanistique catalysée par le palladium, faisant intervenir une β-H élimination suivie d'une insertion d'imine est proposée. fr / Dans la deuxième partie de cette thèse, est présenté une réaction de couplage à trois composés entre aldéhydes, alcynes et hydroxylamines alkyles, catalysée par un complexe CuCl/bipy, pour la synthèse de β-lactames. fr / Dans la dernière partie de cette thèse, est présenté un travail en collaboration avec le département de biochimie sur l'étude de dérivés de thioxothiazolidinone comme inhibiteurs cellulaires de la protéine tyrosine phosphatase 1B. Ces dérivés de thioxothiazolidinone furent synthétisés et leurs activités biologiques furent étudiées. fr

DNA has emerged as a promising template for the programmable assembly of structures on the nanometer scale. In particular, DNA nanotubes hold promise for a number of biological and materials applications, because of their high aspect ratio and encapsulation potential. Current construction methods result in symmetrical and cylindrical assemblies that are totally double-stranded, and are long and polydisperse. In order to investigate DNA nanotubes for applications as well-defined molecular hosts and one-dimensional templates, better control over their geometry, stiffness and porosity, ability to encapsulate and length needs to be achieved. Specifically, the first section of this thesis will describe (a) a modular approach to construct DNA nanotubes of geometrically well-defined triangular and square-shapes, which can exist in either double- and single-stranded forms with different stiffnesses, (b) the construction of DNA nanotubes with longitudinal variation by alternating larger and smaller capsules along the tube length, the encapsulation of guest molecules within these DNA nanotubes as well as their selective release with externally added DNA strands, (c) the use of a DNA-templated approach to produce nanotubes with controlled pre-determined lengths of 1 μm, and 500 nm and narrow length distributions, and the encapsulation of gold nanoparticles within these well-defined nanotubes to form finite lines of gold nanoparticles with longitudinal plasmon coupling. While DNA is a very promising construction material, it suffers from serious drawbacks for practical applications in materials science and biology. DNA is difficult and expensive to obtain in large quantities, and has limited long-term stability. On the other hand, synthetic polymers are routinely used as building blocks for nanostructured materials, with multiple applications in areas ranging from optics and data storage, to separation science and biology. Thus, an important challenge is the creation of / L'ADN s'est récemment manifesté comme un matériau prometteur pour l'assemblage programmable de structures à l'échelle nanométrique. En particulier, les nanotubes d'ADN sont intéressants pour leurs applications en science des matériaux et en biologie, en raison de leur aspect linéaire et leur potentiel d'encapsulation. Les méthodes courantes de leur synthèse produisent des assemblées symétriques et cylindriques totalement constituées de doubles brins d'ADN longs et polydisperses. Afin d'examiner les nanotubes d'ADN pour leurs applications comme des hôtes moléculaires à structure bien-définie et comme modèles unidimensionnels, des méthodes de synthèse qui mènent à un plus haut niveau de contrôle de leur géométrie, rigidité, porosité, capacité d'encapsulation et longueur doivent être développées. Plus précisément, la première section de cette thèse décrira (a) une approche modulaire pour construire des nanotubes d'ADN géométriquement bien définis, triangulaires ou carrés, et pouvant exister en formes d'ADN double-brin ou brin simple avec des différences de rigidité, (b) la construction des nanotubes d'ADN avec une variation longitudinale, en alternant les grandes et les petites capsules le long du tube, et l'encapsulation de matériaux invités au sein de ces nanotubes d'ADN, ainsi que leur libération sélective sous l'action de brins d'ADN externes ajoutés, (c) l'utilisation de l'approche d'un modèle d'ADN pour produire des nanotubes avec des longueurs contrôlées et prédéterminées de 1 µm ou de 500 nm et des distributions de longueurs étroites, et l'encapsulation de nanoparticules d'or au sein de ces nanotubes bien définis pour former des lignes de longueurs bien définies de nanoparticules d'or avec un couplage plasmonique longitudinal. Bien que l'ADN soit une molécule très intéressante pour l'auto-assemblage de structures, son utilisation comme un outil dans les applications pratiques en science des maté

This thesis describes the investigation of various amino acids derivatives as reagents for copper-catalyzed, silver-catalyzed and iron-catalyzed reactions and the investigation of an enantioselective cobalt-catalyzed aldehyde-alkyne-amine (A3) coupling reaction. The first part focuses on the large-scale optimization of the oxidative amidation of aldehydes in the presence of amine hydrochloride salts as well as our effort to enhance the reaction scope by the use of amino acids derivatives and short peptides. This is then followed by the development of an enantioselective cobalt-catalyzed A3-coupling using binaphthol ligands as a source of chirality. Finally, the last part involves silver-catalyzed alkyne addition to iminoesters as well as silver-catalyzed A3-coupling. / La présente thèse a pour but de présenter l'utilisation de divers dérivés d'acides aminés comme substrats pour plusieurs réactions catalysées par des sels de cuivre, d'argent et de fer, de même que du développement d'une réaction de couplage énantiosélective entre aldéhyde, alcyne et amine (A3) catalysée par des sels de cobalt. La première partie met l'emphase sur l'optimisation à grande échelle d'un procédé d'amidation oxydative d'aldéhydes en présence de sels d'amine ainsi que nos efforts pour adapter cette méthode à des substrats tels que courts peptides et dérivés d'acides aminés. Cela est suivi par le développement d'une réaction de couplage énantiosélective entre aldehyde, alcyne et amine (A3) catalysée par des sels de cobalt misant sur l'utilisation de binaphtols comme ligands chiraux. La dernière partie porte sur l'addition d'alcyne à des iminoesters catalysés par des sels d'argent ainsi que sur des réactions de couplage A3, elles aussi catalysées par des sels d'argent.

The kinetics and mechanism of hydrolysis of both activated and unactivated phosphate diesters in the presence of aqueous solutions of Ce(III) salts are studied in detail. In the presence of 20 mM Ce$ rm (ClO sb4) sb3 (pH 8, 37 sp circ C)$ a DNA dinucleotide (dApdA) is converted to the nucleoside (dA) and inorganic phosphate with a half-life of approximately 100 minutes. This reaction is oxygen dependent and a mechanism involving the activation of oxygen by Ce(III) to give a Ce(IV) coordinated peroxide dianion as the active species is proposed. / The addition of 20 mM hydrogen peroxide to 2mM La(III) (pH 7.0, 25$ sp circ$C) results in a 34,000 fold increase in the rate of BNPP hydrolysis over that observed in the presence of 2mM La(III) alone and an overall 5 x l0$ sp8$ fold rate increase over the uncatalyzed rate. Incorporation of $ sp{18}$O from hydrogen peroxide into the inorganic phosphate product and evidence from the reaction kinetics and potentiometric titrations indicate that the mechanism involves nucleophilic attack of a La(III) coordinated peroxide dianion upon the substrate. / La(III) hydroxide clusters formed from the combination of La(III) (20 mM) and NaOM (40 mM) rapidly converts an RNA dinucleotide (ApA) to the monophosphates (2$ sp prime$-AMP and 3$ sp prime$-AMP) (t$ sb{1/2}$ = 8 sec at pH 8.7, 20$ sp circ$C). The presence of molecular oxygen does not improve the efficiency of Ce(III) in cleaving ApA; however, it does assist in the cleavage of the monophosphates which are not cleaved by Ce(III) in the absence of O$ sb2$ or La(III).