Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study was carried out in three parts: At first, three methods for the bromination of 6-alkylsubstituted 2-phenyl-3H-pyrimidin-4-ones was developed for the synthesis of: (i) a new series of 6-alkylsubstituted 5-bromo-2-phenyl-3H-pyrimidin-4-ones, (ii) a new series of 6-(1-bromoalkyl)-2-phenyl-3H-pyrimidin-4-ones, and (iii) e new series of 5-bromo-6-(1-bromoalkyl)-2-phenyl-3H-pyrimidin-4-ones. On the second part, the brominated pyrimidines obtained, were used to synthesize new 6-methylsubstituted 2-phenyl-3Hpyrimidin-4-ones from the reaction of the brominated pyrimidinones with primary and secondary amines, pyridine and sodium azide. On the third part, a new series of 5- e 6-substituted 4-trifluoromethyl-2-ureido pyrimidines was prepared, in good yields, from the cyclocondensation reaction of β- alkoxyvinyl-trifluoromethylketones substituted and dicyanodiamide. The products synthesized in this study were obtained in good yields and were characterized by GC-MS and 1H e 13C RMN spectroscopy. The purity of the products was assured by elemental analysis. Some compounds such as 5-bromo-2-phenyl-6-propyl-3H-pyrimidin-4-one, 5-bromo-6-(1- bromopropyl)-2-phenyl-3H-pyrimidin-4-one, 5-bromo-6-(1-bromobutyl)-2-phenyl-3H-pyrimidin-4-one, 6-(1-azidoethyl)-5-bromo-2-phenyl-3H-pyrimidin-4-one, 6-(1-azidopropyl)-5-bromo-2-phenyl-3H-pyrimidin-4-one, and 6-(1-azidobutyl)-5-bromo-2-phenyl-3H-pyrimidin-4-one, exhibited significant antimicrobial activity against some microorganisms, such as Candida albicans, Saccharomyces cerevisiae, Staphylococcus aureus, Salmonela, Klebsiela pneumonie among others. / Este trabalho foi realizado em três etapas. Na primeira, foram desenvolvidos três métodos de bromação de 2-fenil-3H-pirimidin-4-onas 6-alquilsubstituídas para a obtenção de: (i) uma série inédita de 5-bromo-2-fenil-3H-pirimidin-4-onas 6-alquilsubstituídas, (ii) uma série inédita de 6-(1- bromoalquil)-2-fenil-3H-pirimidin-4-onas e (iii) uma série inédita de 5-bromo-6-(1-bromoalquil)-2-fenil-3H-pirimidin-4-onas. Na segunda etapa, as pirimidinas bromadas, obtidas na etapa anterior, foram utilizadas para sintetizar novas 2-fenil-3H-pirimidin-4-onas 6-metilsubstituídas através de reações das pirimidinonas bromadas com aminas primárias e secundárias, piridina e azida de sódio. Na terceira etapa, foi sintetizada uma nova série de 4-trifluormetil-2-ureído pirimidinas 5- e 6-substituídas a partir de reações de ciclocondensação entre -alcoxivinil-fluormetilcetonas substituídas e dicianodiamida. Os produtos sintetizados neste trabalho foram obtidos em bons rendimentos e foram caracterizados por CG-EM e RMN de 1H e 13C. A pureza dos produtos foi comprovada por análise elementar. Alguns compostos como 5-bromo-2-fenil-6-propil-3H-pirimidin-4-ona, 5-bromo-6-(1-bromopropil)-2-fenil-3H-pirimidin-4-ona, 5-bromo-6-(1-bromobutil)-2-fenil-3Hpirimidin-4-ona, 6-(1-azidoetil)-5-bromo-2-fenil-3H-pirimidin-4-ona, 6-(1- azidopropil)-5-bromo-2-fenil-3H-pirimidin-4-ona e 6-(1-azidobutil)-5-bromo-2-fenil-3H-pirimidin-4-ona, apresentaram atividade antimicrobiana significativa contra alguns microorganismos como Candida albicans, Saccharomyces cerevisiae, Staphylococcus aureus, Salmonela, Klebsiela pneumonie e outras.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

<p>Deep vein thrombosis (DVT) and Pulmonary embolism (PE) are responsible for over 900,000 cases and 100,000 deaths each year in the US. Direct fibrinolytic agents such as plasmin are being investigated for their treatment. However, plasmin administration is not widely studied as low plasmin concentrations are rapidly inactivated by antiplasmin in vivo, whereas high plasmin doses would deplete endogenous antiplasmin and impose bleeding risks. Thus, a plasmin delivery system that can achieve efficient clot lysis while minimizing inactivation by antiplasmin and has reduced bleeding risks is needed. To address this, we propose using reversible inhibitors of plasmin that can sequester plasmin from antiplasmin and release it on the surface of a fibrin clot to achieve clot lysis. The inhibition must be tuned such that it is strong enough to protect plasmin from antiplasmin and weak enough to release plasmin at the clot for lysis. To achieve this, we utilize principles of multivalency to synthesize three classes of inhibitors with varying potencies and mechanisms of inhibition: (i) Multivalent benzamidines (ii) Multivalent tranexamic acids (TXA), and (iii) Hetero-multivalent inhibitors having both benzamidine and TXA. Benzamidine is a competitive inhibitor of plasmin’s active site. TXA, on the other hand, is an FDA-approved weak active site inhibitor that is primarily used to disrupt plasmin(ogen) from binding to fibrin on the clot by inhibiting plasmin’s kringle domains. Multivalent inhibitors were synthesized using amine-reactive chemistry, purified using RP-HPLC and confirmed with Mass Spectrometry. Inhibition assays were performed to assess inhibition potency by determining Ki values (inhibition constants). Lower Ki values indicate stronger inhibition. With multivalent benzamidine derivatives, it was observed that changing valency and linker length substantially impacted inhibition and resulted in Ki values ranging from 2.1 to 1,395 μM. Inhibitors of higher valencies and shorter linker lengths exhibited stronger inhibition. Multivalent TXAs of valencies 1 to 16 were also tested and they exhibited Ki values varying from 2.5 to 21,370 μM indicating up to 8,548-fold improvement in inhibition due to valency. It was found that monovalent TXA, primarily a kringle inhibitor, can be converted into a stronger active site inhibitor by multivalency. With hetero-bivalent TXA-dPEG36-AMB, simultaneous binding of benzamidine to the active site and TXA to the kringle domains was achieved to attain improved inhibition. These results indicate that multivalency can significantly alter the potency of inhibitors and can modulate plasmin inhibition for drug delivery.</p>

Human African trypanosomiasis (sleeping sickness) is a devastating disease which is endemic in parts of sub-Saharan Africa. It is caused by the protozoan parasite T. brucei, which are transmitted by the bite of infected tsetse flies. Although the disease is fatal if left untreated, there is a lack of safe, effective and affordable drugs available; therefore new drugs are urgently needed. The aim of the work presented in this thesis is to develop novel trypanocidal compounds. It is divided into two parts to reflect the two distinct strategies employed to achieve this aim. The first part focuses on the inhibition of glycophosphoinositol (GPI) anchor synthesis by inhibiting the Zn2+-dependent enzyme, GlcNAc-PI de-N-acetylase. Trypanosomes have a variable surface glycoprotein (VSG) coat, which allows them to evade the human immune system. The GPI anchor attaches the VSG to the cell membrane; therefore inhibiting GPI synthesis should expose the parasite to the immune system. Initially, large substrate analogues were synthesized. These showed weak inhibition of the enzyme. Zinc-binding fragments were screened, and small molecule inhibitors based on salicylhydroxamic acid were then synthesized. These compounds showed modest inhibition, but the excellent ligand efficiency of salicylhydroxamic acid indicates this may be a promising starting point for further inhibitors. The second part details the P2 strategy. The P2 transporter is a nucleoside transporter unique to T. brucei, which concentrates adenosine. The transporter also binds and selectively concentrates compounds that contain benzamidine and diaminotriazine P2 motifs, which can enhance the potency and selectivity of these compounds. The sleeping sickness drugs melarsoprol and pentamidine contain P2 motifs. Compounds comprising a P2 targeting motif, a linker and a trypanocidal moiety were synthesized. Initially, a diaminotriazine P2 motif was attached to a trypanocidal tetrahydroquinoline (THQ) protein farnesyl transferase (PFT) inhibitor, with limited success. The P2 strategy was also applied to a non-selective, trypanocidal, quinol moiety. The quinol moiety was attached to diaminotriazine and benzamidine P2 motifs, and an increase in selectivity for T. brucei over MRC5 cells was observed.

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