<p>The expanded production of shale gas has increased the desire for developing methods for converting light alkanes, especially propane and ethane, into aromatic species (i.e., benzene, toluene, and xylene). A multi-step process for conversion of light alkanes to aromatics may be developed, where the first stage converts light alkanes into olefins and hydrogen, and the second stage converts olefins to aromatics. However, to determine the viability of this process, better understanding of the performance of olefin aromatization in the presence of equimolar hydrogen is necessary. </p> <p><br></p> <p>Previous studies on the conversion of olefins to aromatics with bifunctional ZSM-5 catalysts have concluded that benzene, toluene, and xylenes (BTX) yields are significantly higher than for ZSM-5 alone. These results were attributed to the presence of a dehydrogenation function of Ga or Zn leading to higher rates of aromatics formation. In this study, a highly active, bifunctional PtZn/SiO2 (1.3 wt% Pt, 2.6 wt% Zn) with H-ZSM-5 (Si/Al = 40) catalyst is investigated for propene aromatization at 723 K and 823 K. At low to moderate propene conversions, in addition to BTX, light alkanes and olefins are produced. Many of these may also be converted to aromatics at higher propene conversion while others are not, for example, light alkanes. When compared at equivalent space velocity and propylene conversion, the bifunctional catalyst has a much higher selectivity to aromatics than ZSM-5; however, when compared at equivalent conversion of all reactive intermediates, the bifunctional catalyst exhibits very similar BTX selectivity. At 723 K, for both ZSM-5 and the bifunctional catalyst, the primary non-reactive by-products are propane and butane. At 823 K, both ZSM-5 and the bifunctional catalyst convert propane and butane to aromatics increasing the aromatic yields, and the by-products are methane and ethane.</p> <p><br></p> <p>Additionally, previous studies have investigated the H-ZSM-5 and Ga/H-ZSM-5 in the absence of H2, which is necessary to understand in order to develop a process for the conversion of light alkanes to aromatics. Herein, proton-form ZSM-5 and Ga modified H-ZSM-5 are compared for propylene aromatization in the presence and absence of equimolar hydrogen at 1.9 kPa and 50 kPa partial pressures. At 1.9 kPa, the presence of H2 is shown to have no impact on the product distribution on H-ZSM-5 or Ga/H-ZSM-5. At 50 kPa, H2 is shown to have no significant impact on H-ZSM-5 and has no impact on Ga/H-ZSM-5 at conversions <80%. Additionally, the addition of Ga to H-ZSM-5 is shown to have no impact on the product distribution in the presence or absence of H2, contrary to previous reports. The disagreement with previous literature stems from previous literature comparing H-ZSM-5 and Ga/H-ZSM-5 at equivalent space velocity rather than equivalent propylene conversion despite previous studies showing that the presence of Ga increases the conversion at equivalent space velocity for olefin aromatization. </p>

Novel bifunctional metal-loaded polymer–silica composite (PSC) catalysts were investigated in the hydrodeoxygenation (HDO) of 4-(2-furyl)-3-buten-2-one (FAc) as a model substance for furfural–acetone aldol condensation products. PSC catalysts were synthesized via a sol–gel method with different polymer contents and subsequently doped with different noble metals. The product composition of the HDO of FAc could be tuned by using catalysts with different polymer (i.e., acidic properties) and metal content (i.e., redox properties), showing the great potential of metal-loaded PSC materials as tunable catalysts in biomass conversions with complex reaction networks. Furthermore, high yields (>90%) of the fully hydrodeoxygenated product (n-octane) could be obtained using noble metal-loaded PSC catalysts in only 8 h of reaction time.

No description available.

<p dir="ltr">Immunotherapy has revolutionized the field of oncology. While a lot of antibodies and small molecule inhibitors have been developed for this, a lot of targets remain undruggable in humans.</p><p dir="ltr">Targeted protein degradation has opened a new horizon in drug discovery where we can target these undruggable proteins. Proteolysis targeting chimeras using the ubiquitin-proteasomal system is one of the most popular TPD strategies that complement lysosomal degradation strategies to degrade intracellular proteins, typically using bifunctional small molecule degraders. Recently, large biomolecular and antibody conjugates have been developed for degrading membrane and extracellular proteins in cells, such as lysosomal targeting chimeras (LYTACs) and genetically encoded LYTACS, among several others. However, larger molecules have limitations in penetrating solid tumors. This dissertation work focused on the development of bifunctional small molecule degraders for programmed death-ligand 1 (PD-L1), a transmembrane protein ligand for the immune checkpoint programmed cell death 1 (PD-1). PD-L1 is highly expressed on several tumors, such as triple-negative breast cancer (TNBC), non-small cell lung carcinoma, and renal cancer, and is known to suppress cancer-killing immune cells via interaction with PD-1 on T-cells. In addition, PD-L1 is also present on macrophages in the tumor microenvironments leading to further immune suppression and acquired resistance to anti-PD-1 therapy is associated with the upregulation of alternative immune checkpoints, thereby reducing anti-tumor efficacy. We have designed and synthesized bifunctional small molecules as PD-L1 degraders with different recruiters and linkers guided by computational studies with known PD-1/PD-L1 structures to show both cell surface and total protein degradation in human TNBC cells. In a separate project, we also developed small molecule conjugates to degrade an intracellular integral membrane protein of the endoplasmic reticulum with an unknown 3D structure, namely Diglyceride acyltransferase 2 (DGAT2). Recently, our lab identified DGAT2 as a new target for combating Alzheimer’s disease. Specifically, DGAT2 catalyzes triacylglycerol (TAG) synthesis using diacylglycerol and fatty acyl CoA as substrates. The accumulation of TAGs, mechanistically linked to DGAT2, results in “fat” or lipid droplets (LDs) inside the cells. Our lab showed that microglial cells (resident immune cells in the brain) accumulate LDs in the postmortem brains of human patients and mouse models (5xFAD) of Alzheimer’s disease and that the LD accumulation is driven by amyloid-beta (Ab) – a hallmark of Alzheimer’s disease – via DGAT2 pathway. Further, these LD-laden microglia have phagocytic defects and are spared Aβ thereby affecting plaque accumulation and clearance. Inhibiting DGAT2 reduces the amount of TAG in the brain, which in turn reduces LDs and restores microglial ability to phagocytose Ab. However, commercially available DGAT2 inhibitors were unable to reduce LD load in older 5xFAD mice. Using AlphaFold’s models of DGAT2, we designed and identified sites to synthesize bifunctional DGAT2 degraders that resulted in reduced LDs in mouse primary microglial cells and enhanced phagocytosis of Aβ plaques in vivo in aged 5xFAD mice. Our approach shows a framework to develop bifunctional small molecule degraders for membrane proteins to potentially combat immune dysregulation in chronic diseases.</p>

Résumé : Grâce à des caractéristiques physiques particulières, le [indice supérieur 64]Cu (T[indice inférieur 1/2]= 12.7 h; β[indice supérieur+], 0.65 MeV [17.8 %]; β[indice supérieur −], 0.58 MeV [38.4 %]) est un candidat idéal pour l’imagerie TEP et la radiothérapie ciblée du cancer. Son utilisation est actuellement limitée par la disponibilité de chélateurs bi-fonctionnels (CBFs) offrant une résistance élevée aux réactions de transmétallation in vivo. Récemment nous avons développés deux nouveaux CBFs cycliques, DOTHA[indice inférieur 2] et NOTHA[indice inférieur 2], portant des ligands hydroxamates pour la complexation au [indice supérieur 64]Cu. Ces CBFs possèdent une cinétique de marquage rapide dans des conditions très douces, une stabilité élevée in vivo et un profil de biodistribution favorable avec une clairance rapide. Nous proposons maintenant d’étendre notre approche à la préparation de CBFs acycliques plus flexibles et compacts afin de moduler les propriétés biologiques et la pharmacocinétique des traceurs peptidiques. Le but de mon projet de maîtrise est de développer une série de chélateurs acycliques dérivés de l'histidine et de l'acide glutamique et fonctionalisés avec des groupements hydroxamates pour identifier un CBF offrant un complexe stable in vivo avec le [indice supérieur 64]Cu(II). Les CBFs ont été préparés en solution pour faciliter l’optimisation de chaque étape réactionnelle. Les groupements chélatants hydroxamates ont été sélectionnés pour leur habilité à former des complexes stables avec différents métaux et ils ont été liés en position N-terminale et sur la chaîne latérale des acides aminés grâce à des réactions de substitution nucléophile. Les groupements para-methoxy-benzyles ont été judicieusement sélectionnés pour la protection des groupements hydroxamates afin de faciliter, au besoin, une déprotection sélective sous des conditions très douces. L’optimisation du marquage a été effectuée avec l’isotope stable du cuivre et ensuite avec le [indice supérieur 64]Cu en faisant varier le contre ion métallique, le pH, la concentration, et la température. Le CBF offrant la plus grande stabilité, soit celui dérivé de l’histidine, a été conjugué à un peptide, le H[indice inférieur 2]N-PEG-[D-Tyr[indice supérieur 6],βAla[indice supérieur 11],Thi[indice supérieur 13],Nle[indice supérieur 14]]bombesin(6-14) (BBN), se liant fortement aux récepteurs de la relâche de la gastrine surexprimés dans les cancers du sein et de la prostate. La stabilité et l’activité spécifique du CBF-histidine et du radiotraceur marqués au [indice supérieur 64]Cu s’est avérée faible in vitro. Il est connu que l’activité antibactérienne de ligands hydroxamates est associée à leur capacité à complexer le fer. En perspective, comme nos chélateurs complexent très fortement le Fe(III), une alternative pour ces composés serait d’évaluer leur capacité à inhiber la croissance et la prolifération des bactéries. || Abstract : Thanks to its particular physical characteristics, [superscript 64]Cu (T[subscript ½= 12.7 h; β[superscript +], 0.65MeV [17.8 %]; β[superscript −], 0.58MeV [38.4 %]) is an ideal candidate for PET imaging and targeted cancer radiotherapy. Currently, its use is limited by the availability of bi-functional chelators (BFCs) which give high resistance to in vivo transmetallation reactions. Recently, we developed two new cyclic BFCs, DOTHA[subscript 2] and NOTHA[subscript 2], bearing hydroxamate pendant arms for the complexation with [superscript 64]Cu. Those BFCs have fast labeling kinetics under very mild conditions, a high in vivo stability and a biodistribution profile which is favorable with a fast clearance. Now, we propose to expand our approach to the preparation of acyclic BFCs, which are more flexible and compact, in order to better modulate biological properties and the pharmacokinetics of the peptidic tracers. The goal of my Master’s degree project is to develop a series of acyclic chelators derived from histidine and glutamic acid and functionalized with hydroxamate pendant arms to identify a BFC that shows highly stable in vivo complexes with [superscript 64]Cu(II). BFCs have been prepared in solution to facilitate the optimization of each reactive step. Hydroxamate chelating groups have been selected for their ability to form stable complexes with different metals and they have been conjugated in N-terminal position and on the lateral chain of amino acids via nucleophilic substitution reactions. Para-methoxy-benzyl groups have been judiciously selected for the protection of the hydroxamate groups to facilitate, if needed, a selective deprotection under mild conditions. The labeling optimization has been performed with a stable copper isotope, and then with [superscript 64]Cu varying the metallic counter-ion, pH, concentration and temperature. The BFC having the highest stability, the one derived from histidine, was conjugated to a peptide, H[subscript 2]N-PEG-[D-Tyr[superscript 6],βAla[superscript 11],Thi[superscript 13],Nle[superscript 14]]bombesin(6-14) (BBN), strongly bounding the gastrin releasing peptide receptor, which is overexpressed in breast and prostate cancers. Both the stability and specific activity of BFC-histidine of the radiotracer labeled with [superscript 64]Cu were low in vitro. It is known that the antibacterial activity of hydroxamate ligands is associated with their ability to complex iron. In perspective, because our hydroxamate ligands strongly complex Fe(III), an alternative for these compounds would be to assess their ability to inhibit the growth and proliferation of bacteria.

1 Abstract This work aims at showing synthesis and potential use of water-soluble fluorescent probes based on BODIPY. The preparation of probes containing bioorthogonal mono- and heterobifunctional functional groups was demonstrated. Ground work was done at the optimisation of reliable, scalable and fast sulfonation of BODIPY in 2,6-positions. A protocol for handling sulfonated BODIPY has been established; especially for the exchange of counterions. In counterion se- lection, their relation to synthetic pathway and biocompatibility were taken into consideration. The second part of the work shows series of water-soluble fluorescent probes, into which can be easily introduced bioactive or bioorthogonal functional groups. This can be used for click chemistry in connection with turn off/on probes or fluorescent sensing of molecules or ions. All this can be done in aqueous solution without organic solvents, which is relevant for biochemical, analytical and imaging applications. Keywords BODIPY, bifunctional, water-soluble, fluorescent probe, solubilization, biocompa- tible probes, bioorthogonal reaction, BODIPY sulfonation

Un des principaux défis lors de l'élaboration des catalyseurs adéquats pour le procédé de déparaffinage catalytique (hydroisomérisation) est de maximiser le rendement en isomères et l'activité du catalyseur, tout en maintenant une faible sélectivité en produits de craquage. En effet, des catalyseurs avec sélectivité de forme à base de zéolithes à taille de pore intermédiaire, par exemple Pt/ZSM-22, sont sélectives en isomères, tandis que les zéolithes à large pore sont plus actifs, mais moins sélectif. L'objectif principal de cette thèse était, alors, d’étudier et de développer un catalyseur à la fois actif et sélectif en isomères. Deux études parallèles ont été realisées: la première basée sur l'impact de la proximité entre les sites actifs sur la réaction (Part I), et la seconde, portant sur le développement d'un catalyseur d'hydroisomérisation de haute performance en utilisant des nanocristaux de zéolithe BEA comme support acide (Part II). La participation de l’épandage d’hydrogène (Hsp) sur le mécanisme de la réaction d'hydroisomérisation a été démontrée. En effet, lorsque les sites actifs sont proches, les espèces Hsp diffusent au voisinage des sites acides provocant l'hydrogénation directe des ions carbénium. Un mécanisme de réaction a, alors, été proposé utilisant ce phénomène comme une alternative au mécanisme classique proposé par Weisz, où la réaction d'hydrogénation a lieu uniquement sur les sites métalliques. Ce phénomène justifie l'activité et la sélectivité plus élevées observées sur les catalyseurs, où les sites actifs sont proches. Sur la deuxième partie de ce manuscrit, des nanocristaux de zéolithe BEA ont été utilisés pour développer un catalyseur d’hy / One of the main challenges when developing adequate catalysts for the catalytic dewaxing process (hydroisomerization) is to maximize the isomerization products yield and the catalyst activity, while maintaining a low selectivity towards light cracking products. Indeed, shape selective catalysts based on medium pore zeolites, e.g. Pt/ZSM-22, were proven to produce high yields of isomerization products, whereas larger pore zeolites were more active but less selective. The main objective of this thesis was, then, to study and develop a catalyst with both high activity and selectivity towards the production of isomerization products. For that two parallel studies were made: the first based on the impact of the proximity between the active sites on the reaction (Part I); and the second, focused on the development of a high performance hydroisomerization catalyst using BEA zeolite nanocrystals as an acid support (Part II). The participation of the spilt-over hydrogen (Hsp) species on the hydroisomerization reaction mechanism played a major role on the study performed on the first part of this manuscript. Indeed, when the active sites were near enough the Hsp species were able to diffuse into the vicinity of the acid sites promoting the direct hydrogenation of the carbenium ions. Due to this fact, a reaction mechanism was proposed using this reaction as an alternative to the classical mechanism proposed by Weisz, where the hydrogenation reaction takes place on the metallic sites. This phenomenon justified the higher activity and selectivity observed on the catalysts where the active sites were sideby side. On the second part of this manuscript nanocrystals of BEA zeolite were

Gene regulation by transcription factors are one of the key processes that are important to sustain all kinds of life. In the prokaryote Escherichia coli this has shown to especially crucial. The operator sequence to which these transcription factors bind to are very small in comparison to the whole genome of E. coli, thus the question becomes how these proteins can find these sequences quickly. One particularly well-studied transcription factor in this regard is the lac repressor. It has been shown that this transcription factors finds its operators faster than the limit of three dimensional diffusion. The leading model for how the repressor does that is facilitated diffusion and this model has gained more experimental evidence, particularly using single-molecule fluorescence microscopy. This study aimed at measuring the unspecific binding time between the lac repressor and DNA in vivo, but in the end the project evolved to trying to establish a single-molecule tracking assay of the repressor in vivo. In this study a mutant of the repressor was expressed and purified, labelled with a synthetic fluorophore, electroporated into E. coli and tracking was performed under a microscope. One of the three types of experiments were partially analysed with an image analysis software. Unfortunately, analysis was not completed for all experiments which made it difficult to compare the results. In the end the data was compared by eye while also using the results from image analysis. With slight optimism it can be concluded that the assay worked, but it needs more development.

Le 1,4,7-triazacyclononane (tacn) fait partie de la famille des polyazamacrocycles et a la faculté, lorsqu’il est N-fonctionnalisé par des groupements coordinants adéquats, de former des complexes de coordination stables thermodynamiquement et inertes cinétiquement avec les métaux de transition. C’est pourquoi les dérivés du tacn trouvent de nombreuses applications dans de nombreux domaines, par exemple celui de l’imagerie médicale. Notre équipe a développé des ligands N-fonctionnalisés par des groupements picolinate et méthylpyridine pour des applications en imagerie TEP et IRM.Le premier travail de cette thèse porte sur l’élaboration de nouvelles sondes bimodales TEP-imagerie optique et IRM-imagerie optique à motifs issus de tacn-picolinate décrits au laboratoire.Une seconde partie est axée sur la synthèse de nouveaux chélates du Cu(II) à base de tacn portant des bras méthylthiazole pour une potentielle application en imagerie TEP. Les complexes de Cu(II) correspondant ont été étudiés par différentes méthodes analytiques et spectroscopiques afin de juger leurs stabilités thermodynamiques et leurs inerties cinétiques.Les chélatants répondant aux critères imposés par le milieu biologique ont été sélectionnés pour une application en imagerie TEP dans le cadre du cancer de la prostate. Des analogues bifonctionnels ont ainsi été élaborés afin de les incorporer dans des radiopharmaceutiques radiomarqués au cuivre-64. / The 1,4,7-triazacyclononane (tacn) is part of the family of polyazamacrocycles, and has the faculty, when appropriately N-functionalized with coordination pendants, to form thermodynamically stable and kinetically inert coordination complexes with transition metals. Thanks to their properties tacn derivatives can be found in numerous applications such as medical imaging. Our group has developed some ligands N-functionalized with picolinate and picolyl pendants for an application in PET imaging and MRI.The first part of this thesis is focused on the development of a new class of bimodal PET-optical imaging and MRI-optical imaging probes based on tacn-picolinate units described in the laboratory.The second part deals with the synthesis of new Cu(II) chelators based on tacn-methylthiazolyl units for a potential application in PET imaging. The corresponding Cu(II) complexes were studied by different analytical and spectroscopic methods in order to evaluate their thermodynamic stabilities and kinetic inertness.The chelators that fullfiled all the criterias imposed by the biological media were selected for an applicationPET imaging of prostate cancer. Some bifunctional analogues were elaborated so as to incorporate them in radiopharmaceuticals radiolabeled with copper-64.

In this thesis will be described research towards the development of bioorthogonal bond-cleavage reactions, and their applications in targeted drug delivery (Figure 1). The first project relates to the development of a palladium mediated bond-cleavage or "decaging" reaction which can cause a propargyl carbamate to decompose and release an amine. This was further developed by the incorporation of a protein modification handle which allowed an amine-bearing drug to be covalently ligated to a protein by a palladium-cleavable linker. This chemistry was demonstrated by the conjugation of the anticancer drug doxorubicin to a tumour targeted anti-HER2 nanobody. The drug could then be delivered to cancer cells upon addition of a palladium complex. The second project relates to the development of a platinum mediated bond-cleavage reaction. This was developed with the aim of using platinum-containing anticancer drugs - such as cisplatin - as a catalyst to cause drug release reactions in tumours. In this reaction an alkyne-containing amide can decompose to release an amine upon addition of platinum complexes, and was applied to the release of prodrugs of the cytotoxins monomethylauristatin E and 5-fluorouracil in cancer cells. A cisplatin-cleavable antibody-drug conjugate was designed and synthesised, and progress towards its biological evaluation will be discussed.