Thin coatings of photoresponsive, pyrimidine-terminated molecules, attached to gold or quartz substrates in contact with water, undego photodimerisation and wettability changes when irradiated with UV light at 280 and 240mm. Spin-casting and chemisorption techniques were used to prepare the thin films. / Thesis (PhDApSc)--University of South Australia, 2000.

The biosynthesis of pyrimidines in Pseudomonas putida was investigated. In this study, pyrimidine requiring mutants were isolated by conventional mutagenesis and enrichment. The strains required exogenously supplied pyrimidines for growth and were found by enzyme assays to be deficient for the product of the pyrB gene encoding the enzyme aspartate transcarbamoylase. None of the intermediates of the pathway could supply the auxotrophic requirement of the strain; only preformed pyrimidines, metabolized via salvage pathways could suffice. Pyrimidine limitation in the mutant caused a slight but significant fifty per cent increase in expression of all the de novo biosynthetic enzymes. Pyrimidine starvation's effect on nucleotide pool levels was examined in the mutant and caused a marked swelling of the purine nucleotide pools.

It has been shown previously in our lab that mutations in the pyrimidine pathway reduced the ability of Pseudomonas aeruginosa to produce virulence factors. Knockout mutations in pyrB, pyrC and pyrD genes of the pyrimidine pathway showed that virulence factor production was decreased. Pyoverdin, pyocyanin, hemolysin, iron chelation, motility, and adherence are all considered virulence factors. Here I further investigate the effects of mutations in the pyrimidine pathway by studying a pyrE mutant. I studied the effect of the pyrE mutation on the production of the above virulence factors. Just like the effect of pyrB, pyrC and pyrD mutations,the pyrE mutation also showed that the bacteria were deficient in producing virulence factors when compared to the wild type. The broader impact of this research would be the possibility of finding drugs that could treat patients infected with P. aeruginosa and possibly extend the lives of chronically infected patients with cystic fibrosis.

Salvage of pyrimidine nucleosides and bases by S. griseus and the regulation of aspartate transcarbamoylase (ATCase) were studied. The velocity-substrate curve for S. griseus ATCase was hyperbolic for both aspartate and carbamoylphosphate. The enzyme activity was diminished in the presence of ATP, CTP, or UTP. The synthesis of ATCase was repressed in cells grown in the presence of exogenous uracil. The specific activity of cells grown with uracil was 43 percent of that for cells grown in minimal medium only. Maximal ATCase and dihydroorotase activities were found in the same column fraction after size-exclusion chromatography, suggesting that both activities could reside in the same polypeptide. The pyrimidine salvage enzymes cytosine deaminase and uridine phosphorylase were identified in S. griseus using HPLC reversed-phase chromatography.

Aspartate transcarbamoylase (ATCase) of Streptomyces was characterized and its interaction with other pyrimidine enzymes explored.

No description available.

Malaria is a parasitic infectious disease that results in millions of clinical cases per year and accounts for approximately 1 million deaths annually. Because the parasite has developed resistance to all current antimalarials, new therapies are urgently needed. Purine and pyrimidine biosynthesis for DNA and RNA synthesis has been recognized as a source of therapeutic targets. Targeted metabolite profiling has aided in the understanding of several biological processes in the parasite besides drug discovery. Therefore, having a robust analytical platform to quantify the purines and pyrimidines is of a great value. For this purpose an ion pair reversed phase ultra-performance liquid chromatography in tandem with mass spectrometry method was developed and validated. In addition, the apicoplast is an organelle present in the malaria parasite and other apicomplexan parasites. It was demonstrated that the apicoplast is essential for parasite's survival. The supply of isopentenyl diphosphate and dimethylallyl diphosphate for isoprenoid biosynthesis is the sole function of this organelle in the asexual intraerythrocytic stages. Isoprenoid precursors are synthesized through the methylerythritol phosphate (MEP) pathway in the malaria parasite while humans utilize the mevalonate pathway. Therefore, the MEP pathway is a source of drug targets for drug development. Our group has identified MMV008138 as anti-apicoplast inhibitor through phenotypic screening. Preliminary data suggest that the molecular target of MMV008138 may be within the MEP pathway. We used proteomic and metabolomic approaches to identify the molecular target of MMV008138 to aid future medicinal chemistry to improve the efficacy of this inhibitor. / Master of Science

La catalyse représente une thématique incontournable de la chimie moderne. Elle occupe une place stratégique dans la recherche de procédés de synthèse plus écologiques et plus économiques en atomes et en énergie. Notre travail réside, d’une part, dans la valorisation d’un biocatalyseur original et, d’autre part, dans la synthèse pallado-catalysée de nouveaux dérivés pyridopyrimidiniques. Dans la première partie, l’utilisation d’un nouveau support naturel préparé à base d’os animal (Animal Bone Meal : ABM) en catalyse hétérogène a été mise en oeuvre, ce qui représente une voie nouvelle et originale, permettant de remplacer les différents catalyseurs solides minéraux connus actuellement et ce, dans diverses réactions classiques de la synthèse organique. Outre les excellents rendements obtenus, les aspects positifs de l’ABM résident dans sa grande stabilité, sa facilité de manipulation et de régénération ainsi que dans l’absence de dangers sur l'environnement. Dans la deuxième partie, une nouvelle stratégie de synthèse simple et efficace de 2,4-di(hét)aryl-pyrido[2,3-d]pyrimidines via un couplage de Suzuki-Miyaura catalysée par le palladium a été développée. Nous avons ensuite étudié la réactivité de diverses 2,4,6-trihalogénopyrido[2,3-d]pyrimidines vis-à-vis des couplages de Suzuki. Cette étude a été étendue à la synthèse de nouvelles 2,4,6-tri(hét)arylpyrido[2,3-d]pyrimidines. / Catalysis is an essential theme of modern chemistry. It occupies a strategic position in the search process more environmentally friendly and more economical energy to atoms and synthesis. Our work lies, on one hand, the development of an original biocatalyst and, secondly, in the pallado-catalyzed synthesis of new derivatives pyridopyrimidiniques. In the first part, the use of a new natural media prepared animal bone (Animal Bone Meal: ABM) based in heterogeneous catalysis has been implemented, which is a new and original way, to replace different solid catalysts currently known minerals and that, in several classical reactions in organic synthesis. In addition to the excellent yields, the positive aspects of ABM lies in its stability, ease of handling and regeneration as well as in the absence of environmental hazards. In the second part, a new strategy for simple and efficient synthesis of 2,4-di(het)aryl-pyrido[2,3-d]pyrimidine via a Suzuki- Miyaura coupling catalyzed by palladium has been developed. We then studied the reactivity of various 2,4,6- trihalogénopyrido[2,3-d]pyrimidine via Suzuki couplings. This study was extended to the synthesis of new 2,4,6- tri(het)arylpyrido[2,3-d]pyrimidine.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / In this study the reactivity of β-enamino diketones [RC(O)C(=CHNMe2)C(O)CO2Et, R = C6H5, 4-Me-C6H4, 4-MeO-C6H4, 4-F-C6H4, 4-Br-C6H4, 4-NO2-C6H4, tien-2-il] with NCN bisnucleophiles as amidine and guanidine was investigated. The tiopirimidines ethyl 2-benzylthio-pyrimidine-4-carboxylates, (65-91 %) and Ethyl 2-metiltiopirimidine-4-carboxylates (69-91 %) were obtained in a highly regioselective manner by cyclocondensation reaction of β-enamino diketones with benzylisothiourea hydrochloride and methylisothiourea sulfate, respectively. Following the studies, was also investigated the reactivity of β-enamino diketones with guanidine hydrochloride and was possible to synthesize 2-aminopyrimidines that were obtained in a regioisomeric mixture of compounds with yields of 64-89 % and the reaction of β-enamino diketones with 2-acethylguanidine led to a highly regioselective synthesis of 2-acethylaminopyrimidines-4-carboxylates in yields (74-88 %). Ethyl 2-benzylthio-pyrimidine-4-carboxylates obtained were cyclized with hydrazine monohydrate and pyrimidopyridazinones were obtained in 52-95 % yields. Finally, were β-enamino diketones were cyclocondensed with 3(5)-amino-5(3)methylpyrazole leading to pyrazolo[1,5-a]pyrimidines of highly regioselective manner. These, in turn, are cyclized with an equivalent amount of hydrazine monohydrate to form a series of pyrazolo-pyrimido-pyridazinone (43-68%) and when using excess hydrazine monohydrate pyrazole-pyridazinone were formed by ANRORC (Addition of Nucleophile followed by Ring-Opening and Ring-Closure)mechanism yields 62-84%. The reactions for the synthesis of these heterocyclic systems involving simple steps, mild conditions and short reaction times. / Nesta tese foi investigada a reatividade de β-enaminodicetonas [RC(O)C(=CHNMe2)C(O)CO2Et, em que R = C6H5, 4-Me-C6H4, 4-MeO-C6H4, 4-F-C6H4, 4-Br-C6H4, 4-NO2-C6H4, tien-2-il] frente NCN dinucleófilos como amidinas e guanidina. As tiopirimidinas 2-benziltio-pirimidinas-4-carboxilato de etila (65-91 %) e 2-metiltiopirimidinas-4-carboxilatos de etila (69-91 %) foram obtidas de maneira altamente regiosseletiva através da reação de ciclocondensação das β-enaminodicetonas com cloreto de benzilisotioureia e sulfato de 2-metilisotioureia, respectivamente. Já nas reações com cloridrato de guanidina foram obtidas 2-aminopirimidinas numa mistura regioisomérica de compostos com rendimentos de 64-89 % e a reação de β-enaminodicetonas com 2-acetilguanidina conduziu a uma síntese altamente regiosseletiva das 2-acetoamidopirimidinas-4-carboxilatos de etila em rendimentos de (74-87%). As 2- benziltio-pirimidinas-4-carboxilato de etila foram escolhidas para verificar o potencial sintético das pirimidinas sintetizadas, e, através da reação de ciclização destas com monoidrato de hidrazina foram obtidas as pirimido-piridazinonas, (52-95 %). Por fim, as β-enaminodicetonas foram ciclocondensadas com 3-(5)-amino-5(3)metilpirazol formando pirazolo[1,5-a]pirimidinas de maneira altamente regiosseletiva. Essas, por sua vez, foram ciclizadas com quantidade equivalente de monoidrato de hidrazina formando uma série de pirazolo-pirimido-piridazinona (43-68 %) e quando cilcizadas utilizando excesso de monoidrato de hidrazina formaram pirazolo-piridazinona através do mecanismo ANRORC (Addition of Nucleophile followed by Ring-Opening and Ring-Closure) com rendimentos de 62-84 %. As reações para a síntese desses sistemas heterocíclicos envolveram etapas simples, condições brandas e curtos tempos de reação.

Cette thèse a pour objectif l’identification de nouveaux inhibiteurs de kinase et plus particulièrement de kinases dépendantes de cyclines (CDKs). Des inhibiteurs de CDKs sont en essais cliniques depuis une dizaine d’année. Un faisceau d’informations récentes montre que cette nouvelle classe pharmacologique pourrait prochainement occuper une place prépondérante dans la thérapie antitumorale. L’introduction de cette thèse décrit les principaux inhibiteurs de CDKs en se focalisant sur ceux dont le développement clinique est en cours et sur les structures les plus récemment divulguées (2009 à 2013). Trois molécules avancées en études cliniques s’avèrent intéressantes et s’approchent de la mise sur le marché : la Roscovitine (phase clinique IIb), le Dinaciclib (phase clinique III) et le Palbociclib (phase clinique III). D’un point de vue expérimental, cette thèse se décompose en deux parties principales. La première modulation a consisté à rechercher des nouveaux groupements qui pourraient sur des squelettes déjà connus comme les purines apporter un avantage en ce qui concerne l’activité des produits. Les structures cristallines des complexes inhibiteur-enzymes et notamment celles de Roscovitine-CDK2 et CR8-CDK2 ont guidé la conception des nouvelles molécules. C’est ainsi que sur les structures biaryliques déjà connues, un groupement phénol a été greffé sur l’un des cycles conduisant ainsi à de nouveaux inhibiteurs de kinases. Ces molécules sont plus puissantes que les produits non hydroxylés. L’augmentation de l’activité est particulièrement sensible au niveau de la kinase CDK2 qui est impliquée notamment dans régulation du cycle cellulaire. La seconde partie du travail porte sur la recherche de structures isostères des purines. Ainsi, le squelette thieno[3,2-d]pyrimidines a été développé de novo. Deux types d’intermédiaires produits ont été préparés afin de permettre la diversification des structures. En premier temps la voie de synthèse via l’intermédiaire thiométhyle a été conduite, néanmois cette voie présente certaines limites. Le deuxième intermédiaire trihalogéné a permi d’optimiser la préparation des molécules thieno[3,2-d]pyrimidines. Les évaluations des produits préparés ne sont pas totalement terminées. Ces molécules sont moins puissantes que les purines sur les CDKs mais agissent au niveau d’autres kinases. / In the introduction, the main functions of cyclin dependent kinases are detailed. Whenever it was possible the link with pathologies where these kinases are overexpressed is presented. This is followed by the description of the inhibitors which are actually undergoing clinical testing. Most of these clinical studies are targeting cancer and leukemia. Impressive clinical results have been disclosed for Dinaciclib, Palbociclib and Roscovitine. The synthesis of two series of compounds is then envisioned. The first series of products are purine derivatives bearing a hydroxybiarylmethyl group on the 6 position of the purine scaffold.  Two approaches were compared in the synthesis of the hydroxylbiarylmethylamino group. In both approaches the key step was the orthoformylation of phenols using magnesium chloride as catalyst. The prepared compounds were evaluated against kinases and a tumor cell line. They were found more potent than homologous products without hydroxyls. The second families of products are thieno[3,2-d]pyrimidines. A new general route to these products based on the preparation of 7-bromo-2,4-dichloro-thieno[3,2-d]pyrimidine which can allow the synthesis of a large diversity of trisubstituted derivatives.