37 research outputs found
Catalyseurs à base de complexes organométalliques supportés par des calixarÚnes
In the past few decades, organometallic catalysis has revolutionised the field of organic chemistry. Indeed, it allows for complex transformations of organic substrates to be obtained in very good yields and soft conditions. Among these, palladium-catalysed bond forming reaction (C-C or C-X) are of central importance. As a consequence, Pd-catalysed organometallic chemistry constitutes an essential tool for modern chemists, both in academic and industrial environments. Despite this performance, this chemistry come with several drawbacks. For example, contamination of reaction products with residual palladium is systematically observed, and this is a central issue in the pharmaceutical industry due to the intrinsic toxicity of this metal. Different techniques allowing for catalysts immobilisation onto solid supports have been developped to overcome these problems, but lower performances are usually observed resulting in added costs for users. During this PhD thesis, we showed that Calixarenes (an important class of macrocyclic compounds) can be used as supports for Pd complexes, thereby offering relevant solutions to these concerns. These new families of supported catalysts indeed allow for both very high reactivity and low palladium leaching in final products to be observed, thus combining in one system the respectivs advantages of both homogeneous and heterogeneous catalysis. These results are opening new perspectives in the field of organometallic catalysis.La catalyse organomĂ©tallique constitue une avancĂ©e majeure dans le domaine de la chimie. Elle a rĂ©volutionnĂ© le domaine de la synthĂšse organique en rendant possible des transformations complexes de substrats organiques dans des conditions douces. Parmi ces transformations, les crĂ©ations de liaisons (carbone-carbone ou carbone-hĂ©tĂ©roatome) catalysĂ©es par des complexes du palladium occupent une place centrale. La catalyse au palladium est ainsi devenue un outil essentiel pour les chimistes, que ce soit en milieu acadĂ©mique ou industriel. Bien que trĂšs performante et largement optimisĂ©e, elle prĂ©sente encore toutefois un certain nombre de difficultĂ©s, liĂ©es en particulier Ă la prĂ©sence de palladium rĂ©siduel dans les produits obtenus en fin de rĂ©action. Ceci pose en effet des problĂšmes de toxicitĂ©, essentiels dans le domaine pharmacologique. Des techniques dâimmobilisation de ces catalyseurs sur des supports solides ont Ă©tĂ© dĂ©veloppĂ©es pour rĂ©soudre ces problĂšmes, mais le plus souvent au prix dâune perte dâefficacitĂ© entraĂźnant des coĂ»ts supplĂ©mentaires pour les industriels utilisateurs. Au cours de cette thĂšse, nous avons montrĂ© que les calixarĂšnes, une importante classe de macrocycles organiques, permettent dâapporter des solutions pertinentes Ă ces problĂ©matiques. En effet, utilisĂ©s comme supports de catalyseurs au palladium, ils permettent dâassocier en un seul systĂšme les performances de la catalyse homogĂšne, avec la faible contamination en palladium permise par la catalyse hĂ©tĂ©rogĂšne. Plusieurs familles diffĂ©rentes de ces catalyseurs au palladium supportĂ©s par des calixarĂšnes ont Ă©tĂ© synthĂ©tisĂ©es, et leurs performances en catalyse ont Ă©tĂ© systĂ©matiquement testĂ©es. Les rĂ©sultats trĂšs intĂ©ressants qui ont Ă©tĂ© obtenus ouvrent des perspectives nouvelles dans le domaine de la catalyse organomĂ©tallique
Calixarenes-supported organometallic catalysts
La catalyse organomĂ©tallique constitue une avancĂ©e majeure dans le domaine de la chimie. Elle a rĂ©volutionnĂ© le domaine de la synthĂšse organique en rendant possible des transformations complexes de substrats organiques dans des conditions douces. Parmi ces transformations, les crĂ©ations de liaisons (carbone-carbone ou carbone-hĂ©tĂ©roatome) catalysĂ©es par des complexes du palladium occupent une place centrale. La catalyse au palladium est ainsi devenue un outil essentiel pour les chimistes, que ce soit en milieu acadĂ©mique ou industriel. Bien que trĂšs performante et largement optimisĂ©e, elle prĂ©sente encore toutefois un certain nombre de difficultĂ©s, liĂ©es en particulier Ă la prĂ©sence de palladium rĂ©siduel dans les produits obtenus en fin de rĂ©action. Ceci pose en effet des problĂšmes de toxicitĂ©, essentiels dans le domaine pharmacologique. Des techniques dâimmobilisation de ces catalyseurs sur des supports solides ont Ă©tĂ© dĂ©veloppĂ©es pour rĂ©soudre ces problĂšmes, mais le plus souvent au prix dâune perte dâefficacitĂ© entraĂźnant des coĂ»ts supplĂ©mentaires pour les industriels utilisateurs. Au cours de cette thĂšse, nous avons montrĂ© que les calixarĂšnes, une importante classe de macrocycles organiques, permettent dâapporter des solutions pertinentes Ă ces problĂ©matiques. En effet, utilisĂ©s comme supports de catalyseurs au palladium, ils permettent dâassocier en un seul systĂšme les performances de la catalyse homogĂšne, avec la faible contamination en palladium permise par la catalyse hĂ©tĂ©rogĂšne. Plusieurs familles diffĂ©rentes de ces catalyseurs au palladium supportĂ©s par des calixarĂšnes ont Ă©tĂ© synthĂ©tisĂ©es, et leurs performances en catalyse ont Ă©tĂ© systĂ©matiquement testĂ©es. Les rĂ©sultats trĂšs intĂ©ressants qui ont Ă©tĂ© obtenus ouvrent des perspectives nouvelles dans le domaine de la catalyse organomĂ©tallique.In the past few decades, organometallic catalysis has revolutionised the field of organic chemistry. Indeed, it allows for complex transformations of organic substrates to be obtained in very good yields and soft conditions. Among these, palladium-catalysed bond forming reaction (C-C or C-X) are of central importance. As a consequence, Pd-catalysed organometallic chemistry constitutes an essential tool for modern chemists, both in academic and industrial environments. Despite this performance, this chemistry come with several drawbacks. For example, contamination of reaction products with residual palladium is systematically observed, and this is a central issue in the pharmaceutical industry due to the intrinsic toxicity of this metal. Different techniques allowing for catalysts immobilisation onto solid supports have been developped to overcome these problems, but lower performances are usually observed resulting in added costs for users. During this PhD thesis, we showed that Calixarenes (an important class of macrocyclic compounds) can be used as supports for Pd complexes, thereby offering relevant solutions to these concerns. These new families of supported catalysts indeed allow for both very high reactivity and low palladium leaching in final products to be observed, thus combining in one system the respectivs advantages of both homogeneous and heterogeneous catalysis. These results are opening new perspectives in the field of organometallic catalysis
OstĂ©onĂ©crose aseptique de tĂȘte fĂ©morale : rĂ©sultats des traitements de premiĂšre intention (Ă propos de 116 cas )
DIJON-BU MĂ©decine Pharmacie (212312103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF
Fracture du col du fémur (voie de Röttinger versus voir de Hardinge pour prothÚse totale de hanche)
Résumé françaisDIJON-BU Médecine Pharmacie (212312103) / SudocSudocFranceF
Mortalité à 1 an des fractures de l extrémité proximale du fémur (étude épidémiologique et comparative)
Introduction : La fracture de l extrémité proximale du fémur est une pathologie fréquente du sujet ùgé, lourde de conséquences en termes de morbi-mortalité. Les objectifs de notre étude étaient de comparer deux techniques chirurgicales : arthroplastie et ostéosynthÚse en terme de mortalité et de récupération fonctionnelle à 1 an et d identifier des facteurs de risque de mortalité dans l année suivant l intervention. Matériel et méthode : Etude rétrospective, consécutive, monocentrique, comparative portant sur 2 groupes de 100 patients l un pris en charge pour une fracture pertrochantérienne (ostéosynthÚse) et l autre pour une fracture intracapsulaire déplacée du col fémoral (arthroplastie). Nous avons effectué un relevé des critÚres épidémiologiques préopératoires et un contrÎle téléphonique à 1 an. Résultats : Age moyen 83,4 ans. La mortalité à 1 an était de 22,5% (2 perdus de vue) sans différence entre les fractures pertrochantériennes et fractures du col fémoral. La récupération fonctionnelle à la marche à 1 an était significativement meilleure aprÚs l arthroplastie pour fracture du col fémoral. L institutionnalisation était significativement plus importante à 1 an aprÚs une ostéosynthÚse pour une fracture pertrochantérienne. En analyse multivariée, l ùge et les comorbidités cardiaques étaient des facteurs prédictifs de mortalité à 1 an. Conclusion : Ces fractures du sujet ùgé restent de mauvais pronostic. La mortalité n est pas influencée par la technique opératoire, ceci s explique par une meilleure récupération fonctionnelle avec l arthroplastie. Elle est liée au terrain. L identification et la prise en charge des facteurs de risque de mortalité pourraient permettre d améliorer le pronostic vital de ces fractures.DIJON-BU Médecine Pharmacie (212312103) / SudocSudocFranceF
Sustainable Development, Planning and Poverty Alleviation
In 2018, the world population is around 7.6 billion, 4.2 billion in urban settlements and 3.4 billion in rural areas. Of this total, according to UN-Habitat, 3.2 billion of urban inhabitants live in southern countries. Of them, one billion, or nearly a third, live in slums. Urban poverty is therefore an endemic problem that has not been solved despite all initiatives taken to date by public and private sectors. This global transformation of our contemporary societies is particularly challenging in Asia and Africa, knowing that on these two continents, less than half of the population currently lives in urban areas. In addition, over the next decades, 90% of the urbanization process will take place in these major regions of the world. Urban planning is not an end in itself. It is a way, human and technological, to foresee the future and to act in a consistent and responsible way in order to guarantee the well-being of the populations residing in cities or in their peripheries. Many writers and urban actors in the South have criticized the inadequacy of urban planning to the problems faced by the cities confronting spatial and demographic growth. For many of them the reproduction of Western models of planning is ineffective when the urban context responds to very different logics. It is therefore a question of reinventing urban planning on different bases. And in order to address the real problems that urban inhabitants and authorities are facing, and offering infrastructures and access to services for all, this with the prospect of reducing poverty, to develop a more inclusive city, with a more efficient organization, in order to make it sustainable, both environmental than social and economic. The field work carried out during recent years in small and medium-sized cities in Burkina Faso, Brazil, Argentina and Vietnam allows us to focus the attention of specialists and decision makers on intermediate cities that have been little studied but which are home to half of the world's urban population. From local diagnoses, we come to a first conclusion. Many small and medium-sized cities in the South can be considered as poor cities, from four criteria. They have a relatively large percentage of the population is considered to be poor; the local government and its administration do not have enough money to invest in solving the problems they face; these same authorities lack the human resources to initiate and manage an efficient planning process; urban governance remains little open to democratic participation and poorly integrates social demand into its development plans. Based on this analysis, we consider it is imperative to renovate urban planning as part of a more participatory process that meets the expectations of citizens with more realistic criteria. This process incorporates different stages: an analysis grounded on the identification of urban investment needed to improve the city; the consideration of the social demands; a realistic assessment of the financial resources to be mobilized (municipal budget, taxes, public and international external grants, public private partnership); a continuous dialogue between urban actors to determine the urban priorities to be addressed in the coming years. This protocol serves as a basis for comparative studies between cities in the South and a training program initiated in Argentina for urban actors in small and medium-sized cities, which we wish to extend later to other countries of the South
A Calix[8]arene-Based Catalyst for Suzuki–Miyaura Couplings with Reduced Pd_Leaching
Pd-catalysed reactions are amongst the most important in current chemistry. Consequently, very reactive catalysts were developed during the last decades, allowing very high conversions at low catalytic rates. However, decreasing Pd leaching in final products without decreasing catalyst efficiency remains an unsolved issue, especially in the pharma industry. We recently showed that using calixarenes as platforms for Pd-based catalysts constitutes an efficient answer to this concern. In the present work, we show that using these calixarenic platforms in combination with suitably engineered ligands allows for an even more strongly decreased Pd leaching. It thus opens up interesting perspectives for the synthesis of new families of catalysts combining a very high reactivity and a very low Pd leaching in final products
A Calix[8]arene-Based Catalyst for SuzukiâMiyaura Couplings with Reduced Pd_Leaching
Pd-catalysed reactions are amongst the most important in current chemistry. Consequently, very reactive catalysts were developed during the last decades, allowing very high conversions at low catalytic rates. However, decreasing Pd leaching in final products without decreasing catalyst efficiency remains an unsolved issue, especially in the pharma industry. We recently showed that using calixarenes as platforms for Pd-based catalysts constitutes an efficient answer to this concern. In the present work, we show that using these calixarenic platforms in combination with suitably engineered ligands allows for an even more strongly decreased Pd leaching. It thus opens up interesting perspectives for the synthesis of new families of catalysts combining a very high reactivity and a very low Pd leaching in final products