Organometallic pyridazines and compounds derived from them have been of interest in polymer research due to their atypical environmental stability (as compared to other non-aromatic organic semiconductors) as well as their conductivity. The off-metal synthesis and characterization of several pyridazyl thallium, manganese, and rhenium complexes, beginning with fulvenes 1,2- C5H3(COHR)(COR), are reported here. The diacyl fulvenes were treated with hydrazine hydrate to ring close to pyridazines. Next, the pyridazines were converted to their respective thallium salts through treatment with thallium (I) ethoxide. Lastly, the salts were transmetallated into the respective rhenium or manganese complexes through treatment with the respective metal bound to five carbonyl groups and one bromide (MnCO5Br, ReCO5Br). Our research focused on the synthesis of a variety of 5,6-fused ring pyridazines that will act as a model for homeland security research in polymer studies and medicinal research. Synthesis and characterization of several aryl-substituted 5,6-fused ring pyridazines have been completed. The fulvenes, pyridazines, and thallium salts are important compounds for research due to their reactivity and stability in moisture and air. The complexes synthesized were confirmed using mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis. Single crystal X-ray diffraction confirmed the structure of x compound 1A. As evidenced by related previous papers published by the research group, the synthesized complexes displayed stability to air, moisture, and temperature.18, 19, 23, 25

Heterocyclic’s and their fused-ring derivatives have been of interest for their use in electronic materials due to their ease of production, synthetic versatility, and low cost compared to traditional inorganic materials like silicon. Pyridazines have been found to be useful in catalysis gas storage, polymeric sensors and biological mimetics. When a transition-metal is fused into a synthesized pyridazine, unique properties such as conductivity and optics are allowed. In this work, synthesized pyridazine complexes will be analyzed by mass spectroscopy, elemental analysis, nuclear magnetic resonance, imaging, x-ray crystallography, and infrared spectroscopy. We are interested in synthesizing organometallic pyridazines and manganese pyridazyl complex for polymer research. Off-metal synthesis and characterization of manganese pyridazyl complex required three intermediate steps. The research focuses on the synthesis and characterization of various manganese pyridazyl complexes.

L’introduction d’un atome de fluor sur un composé organique peut avoir une influence importante sur les propriétés chimiques et physico-chimiques de ce composé, ainsi qu’à son activité biologique. Par ailleurs, les hétérocycles représentent une famille de composés intéressante pour l’industrie pharmaceutique et agrochimique avec 70% de nouvelles molécules bioactifs possédant un motif hétérocyclique. Ainsi, le développement des méthodes de synthèse permettant la formation des hétérocycles trifluorométhylés, représente un défi en chimie organique. Dans le cadre de nos travaux, nous avons dans un premier temps développé une méthode afin d’accéder aux α (trifluorométhyl)pyrrolidines et α (trifluorométhyl)pipéridines substituées, par contraction de cycle de (trifluorométhyl)pipéridines et (trifluorométhyl)azépanes respectivement via un intermédiaire aziridinium. L’attaque régiosélective du nucléophile sur l’aziridinium est induite dû au groupement CF3 présent sur cet intermédiaire. Dans un deuxième temps, nous avons développé une séquence de cycloadditions [2+1]/[3+2] entre un alcyne terminal, un difluorocarbène et le (trifluorométhyl)diazométhane, afin d’accéder aux α (trifluorométhyl)pyridazines fonctionnalisées. / The introduction of a fluorine atom in an organic compound can have major impact on the compounds chemical and physico-chemical properties, therefore influencing its biological activity. Moreover, heterocycles represent an important class of compounds for the pharmaceutical and agrochemical industry, given that 70% of the biologically-active molecules possess a heterocyclic moiety. Therefore, the development of synthetic methods which allow access to trifluoromethylated heterocycles represent a challenge in organic chemistry. The work presented in this manuscript is focused on the synthesis of nitrogen containing heterocycles possessing a CF3 group at the α position to the nitrogen. More specifically, a variety of substituted α-(trifluomethyl)pyrrolidines and substituted α (trifluomethyl)piperidines were obtained by the ring contraction of (trifluoromethyl)piperidines and (trifluoromethyl)azepanes respectively via an aziridinium intermediate. The regioselective attack of the nucleophile on the aziridinium is induced by the CF3 group present on the intermediate. Furthermore, a diversity of functionalized α-(trifluoromethyl)pyridazines were obtained by a [2+1]/[3+2] cycloaddition sequence between a terminal alkyne, a difluorocarbene and (trifluoromethyl)diazomethane.

Pyridazines are a heterocyclic aromatic compound containing a characteristic N-N bond that are utilized in many fields, including medicine and electronics. It is this latter field that Dr. Snyder's research group is focused upon. Organometallic compounds are a better conducting material than the current inorganic compounds used in electronics due to better conductance of electricity, lower production cost, and the ability to be formed into thin films. With this in mind, Dr. Snyder's research group has set out to synthesize organometallic compounds for this purpose. Following procedures set forth by Snyder etc, and altered to form an off-metal route, we have successfully synthesized a library of fulvenes, Thalium Cp salts, 5,6 fused pyridazines, and pyridazial complexes. Thalium Cp salts were converted to Rhenium and Magnenese complexes through transmetalation. We have had success with the off-metal route at both higher yields and greater purity than the previous published on-metal route. These compounds have been fully characterized by 1H NMR, 13C NMR, IR, and Elemental Analysis. In addition, progress has been initiated to form Bromo Thiophene complexes following procedures set forth in Snyder, etc and modified for the off-metal route. However only fulvenes, pyridazine, and Thalium Cp salts have been synthesized and characterized by 1H NMR and 13C NMR.

Les motifs imidazo[1,2-a]pyridines et imidazo[1,2-b]pyridazines sont des noyaux très étudiés par la communauté scientifique, notamment dans le domaine thérapeutique. Ceci s’explique en partie par les progrès récents réalisés dans le domaine de la métallocatalyse qui ont permis une fonctionnalisation plus simple de ces molécules. Cependant, les dérivés tricycliques de ces structures sont restés assez peu étudiés malgré le fait que certains de leurs isostères présentent des propriétés biologiques intéressantes. Les travaux de cette thèse ont porté sur deux projets distincts : -La synthèse d’imidazo[1,2-b]pyridazines présentant un troisième cycle diazoté entre les positions 7 et 8, dans le cadre d’un contrat conclu avec la société Sanofi-Aventis. Ces composés, totalement originaux, représentent un véritable défi chimique et leur synthèse a nécessité d’importants travaux de mise au point. Nous avons ainsi employé différentes méthodes de couplages métallocatalysés. -La synthèse d’imidazo[1,2-a]pyridines un troisième cycle pyridinique entre les positions 2 et 3. Ces molécules, peu décrites dans la littérature, n’ont fait l’objet d’aucune évaluation biologique. Dans le but de synthétiser efficacement une chimiothèque intéressante pour ces structures, j’ai développé une méthode d’hétérocyclisation qui nous permet d’obtenir en deux étapes, gràce à des produits de départ très accessible, une importante variété de tricycles. / The imidazo[1,2-a]pyridines and imidazo[1,2-b]pyridazines moeities are very studied by scientific community, specially in therapeutic field. This is mostly due to recent progress in metallocatalyzed couplings which allow easier functionnalization of these structures. However, the tricyclic derivatives of these compounds remained not very studied despite important biological properties of some of there isosters. This thesis is divided in two parts : -The synthesis of imidazo[1,2-b]pyridazines with a dinitrogenated third cycle between the positions 7 and 8 in collaboration with Sanofi-Aventis. These new compounds were a real chemical challenge and their synthesis required important works of development. We used various metallocatalyzed couplings methods. -The synthesis of imidazo[1,2-a]pyridines with a pyridinic cycle between the positions 2 and 3. These molecules, poorly described in the literature, have never been subject to biological study. In order to effectively synthesize an interesting range of these structures, I have developed a new heterocyclization method which allows us to obtain in two steps, starting from commercialy available starting materials, some original tricyclics compounds.

La protéine kinase DYRK1A fait partie du groupe des CMGC kinases et est impliquée dans divers processus neurodégénératifs tels que la maladie d’Alzheimer.Dans ce cadre, une étude topologique a été menée autour d’un hit imidazo[1,2-B]pyridazine identifié par un criblage biologique. Ce composé a servi à concevoir des inhibiteurs ATP-Compétitifs de DYRK1A par l’utilisation de méthodes métallo-Catalysées (Pd, Cu) pour introduire divers fragments fonctionnalisés.Sur les soixante dérivés imidazo[1,2-X]azine synthétisés, sept composés ont montré une affinité nanomolaire pour DYRK1A (IC50 = 41-130 nM). En parallèle de ce travail de pharmacochimie, le développement de nouvelles méthodologies de synthèse a visé à la polysubstitution régiosélective du cycle pyridazine.En dernier lieu, nous avons donné les éléments et concepts permettant la construction de chimiothèques virtuelles dérivées de pyridazines et destinées à être criblées in silico. / DYRK1A protein kinase belongs to the CMGC group and is involved in neurodegenerative disorders such as Alzheimer’s disease.In this context we examined an imidazo[1,2-B]pyridazine hit identified by biological screening, through detailed structure-Activity relationship studies. This compound was used to synthesize DYRK1A ATP-Competitive inhibitors by using metallo-Catalyzed methodologies (Pd, Cu) in order to introduce various functionalized moieties.Out of the 60 derivatives synthesized, 7 compounds showed nanomolar activities (IC50 = 41-130 nM).Beside this work of medicinal chemistry, new synthetic methodologies has been developed to regioselectively access polysubstituted pyridazine derivatives. Finally, we developed data and concepts to establish virtual pyridazine libraries for in silico screening.