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No. of bitstreams: 2 Dissertação - Thaís Rosa Marques dos Santos - 2016.pdf: 1811805 bytes, checksum: 381d90956275aee309bb1d2948f724de (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-05-20 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Although the efforts employed by scientific community to discover new anticancer therapies suitable to the increasing cancer incidence and multidrug resistance, its necessary to develop more selective and target driven drugs. Therefore, in this work we have done a screening with LQFM030 analogues, which is a Nutlin-1 analogue, aiming to evaluate their cytotoxic potential. Furthermore, we have evaluated the cytotoxicity, the morphological alterations and the cell death induction mechanisms of the compound LQFM166 in leukemia cell line K562. In parallel, we have investigated the security profile of the compound upon 3T3 basal cell line to estimate its LD50 and the Selectivity Index. The cytotoxicity assays included the tetrazolium salt (MTT) reduction and the Neutral Red Uptake assays, to assess the cytotoxicity of LQFM166 in K562 and 3T3 cell lines, respectively. The investigation of cell death induction mechanisms was carried out using flow cytometry, whereby we have evaluated the cells biochemistry parameters, including cell cycle progression, phosphatidylserine externalization, caspases 3/7, 8 and 9 activity, cytochrome c release from mitochondria, p21, p27, Bax, Bcl-2, cyclin-B1 and NFkB expression, using specific labeling for each assay. Data were analyzed by t test and the difference between control and treated groups averages was considered statistically significant when p<0,05. Regarding leukemia cell line K562, the compound LQFM166 was cytotoxic, showing a dose-time-dependent profile. Morphological alterations were observed after treatment with the compound at cellular and nuclear levels, which corroborate with apoptotic cell death. Additionally, treatment with the IC50 for 48 hours has promoted cellular and molecular changes that characterize this process, including phosphatidylserine externalization, increase of caspases 3/7, 8 and 9 activity, expression of pro-apoptotic proteins Bax, p21and p27, as well as diminution of Bcl-2 and cyclin-B1. We have also observed increase of cytochrome-c release and NFkB expression. Concerning the security profile, the compound was considered relatively selective, once the IC50 found to basal cell line (185,3 µM) was the double of the obtained to leukemia cell line regarding the same time of exposure (56,76 µM). The outcomes allow us to conclude that LQFM166 was cytotoxic upon leukemia cells K562, promoting morphological and biochemical alterations that indicate apoptotic cell death induction. / Mesmo com os esforços da comunidade científica em descobrir ou desenvolver medicamentos adequados a crescente incidência do câncer e ainda adequados à suas formas multirresistentes, é necessário o desenvolvimento de medicamentos que sejam seletivos e alvo-dirigidos. Assim, no trabalho proposto, foi realizada uma triagem com compostos análogos ao LQFM030, análogo estrutural do Nutlin-1, visando determinar o potencial citotóxico dos mesmos. Além disso, foram investigados a citotoxicidade, as alterações morfológicas e os mecanismos de indução de morte celular do composto escolhido LQFM166 em linhagem de células leucêmicas K562. Paralelamente, foi investigado o perfil de segurança do composto sobre a linhagem basal 3T3, a fim de estimar a DL50 e o Índice de Seletividade do mesmo. Os ensaios de citotoxicidade incluíram o método de redução do sal de tetrazólio (MTT) e o método de incorporação do corante vermelho neutro, para a avaliação do potencial citotóxico sobre as linhagens K562 e 3T3, respectivamente. Para a investigação dos mecanismos de indução de morte celular foi utilizada a técnica de citometria de fluxo, por meio da qual foi realizada a avaliação de parâmetros bioquímicos incluindo progressão ciclo celular, externalização da fosfatidilserina, atividade das caspases 3/7, 8 e 9, liberação do citocromo c, expressão das proteínas p21, p27, Bax, Bcl-2, ciclina-B1 e NFkB, empregando-se técnicas de marcação específicas para cada ensaio. Os dados foram analisados pelo teste t e a diferença entre as médias dos grupos controle e tratado foram consideradas estatisticamente significativas quando p<0,05. Em relação à linhagem leucêmica K562, o composto LQFM166 foi citotóxico apresentando um perfil dose e tempo dependentes. Foram observadas alterações morfológicas a níveis celular e nuclear, após o tratamento com composto, condizentes com o processo de morte celular por apoptose. Adicionalmente, externalização da fosfatidilserina, aumento da atividade das caspases 3/7, 8 e 9, aumento da expressão das proteínas pró-apoptóticas Bax, p21 e p27, bem como diminuição da expressão das proteínas Bcl-2 e ciclina-B1, após tratamento com a CI50 por 48 horas, desencadeou alterações celulares e moleculares que reforçam a sugestão de processo de morte celular por apoptose. Observouse ainda aumento da liberação do citocromo-c e da expressão da proteína NFkB. Já em relação ao perfil de segurança, o composto mostrou-se relativamente seletivo e com menor toxicidade, uma vez que a CI50 encontrada para a linhagem basal (185,3 μM) foi cerca de duas vezes maior ao encontrado para a linhagem tumoral para o mesmo tempo de exposição (56,76 μM). Considerando os resultados obtidos, pode-se concluir que o composto LQFM166 foi citotóxico sobre a linhagem leucêmica K562, desencadeando alterações morfológicas e bioquímicas características de morte celular por apoptose.

Fluorine incorporation has become increasingly important in pharmaceutical applications. Upon fluorination and incorporation of fluorinated moieties such as trifluoromethoxy groups, many small molecules become more bioavailable and metabolically stable and additionally can better cross the blood-brain-barrier. This thesis describes the development of a method mediated by silver salts for the synthesis of pharmaceutical-like trifluoromethoxylated compounds via \(C-OCF_3\) bond formation. Additionally the synthesis of 3-deoxy-3-fluoromorphine via late-stage fluorination of morphine is described as well as in vitro and in vivo evaluation of 3-deoxy-3-fluoromorphine as a potential analgesic. / Chemistry and Chemical Biology

Ces dernières années ont été témoin de l'énorme développement de la chimie organique du fluor. Notamment, l'introduction de groupements fluorés émergents sur des « briques » moléculaires variées a attiré l'attention de la communauté scientifique en raison de leurs propriétés particulières. De plus, la stratégie de fonctionnalisation dirigée de la liaison C-H par catalyse par les métaux de transition, a conduit à une révolution dans le développement de méthodologies synthétiques originales. Par conséquent, la conception de nouvelles approches synthétiques pour l'introduction de groupements fluorés par fonctionnalisation de la liaison C-H catalysée par les métaux de transition est particulièrement attirante. Dans cette thèse, nous nous sommes concentrés sur le développement de nouvelles méthodologies d'introduction directe des groupements fluorés sur des arènes et des oléfines par fonctionnalisation directe de liaison C(sp2)-H catalysée par les métaux de transition. En particulier, nous avons tourné notre attention sur le 2-bromo-3,3,3-trifluoropropène (BTP), un réactif fluoré bon marché et provenant de déchets de l'industrie. Ce dernier est utilisé comme agent de remplacement de halon pour la suppression des incendies et, utilisé comme « brique » moléculaire en synthèse organique (Chapitre 1). La première partie de cette thèse est dédiée au développement de nouvelles méthodologies pour l'introduction directe du groupement CF3-vinyl sur des arènes et des oléfines par fonctionnalisation de la liaison C(sp2)-H catalysée par le palladium. Ensuite, cette approche a été étendue à la fonctionnalisation d'esters α,β- insaturés, bien qu'un mécanisme différent soit probablement impliqué (Chapitre 2). Dans la seconde partie de cette thèse, nous avons développé une nouvelle méthodologie pour l'introduction directe du groupement SCF3 sur des arènes et des oléfines par fonctionnalisation de la liaison C(sp2)-H catalysée par le palladium, utilisant le réactif de Munavalli (Chapitre 3). / Recent years have witnessed a great development of the organofluorine chemistry field. In particular, the introduction of emergent fluorinated moieties onto various scaffolds has attracted attention of the scientific community because of their special properties. Besides, transition metal-catalyzed directed C-H bond functionalization strategy has brought a revolution in the development of original synthetic methodologies, since it allows straightforward and more atom-economical processes. Thus, the design of new synthetic approaches for the introduction of fluorinated moieties by transition metal-catalyzed C-H bond functionalization pathway is particularly appealing. Therefore, in this Ph.D. thesis, we focused on the development of new methodologies for the direct introduction of fluorinated moieties onto arenes and olefins by transition metal catalyzed directed C(sp2)-H bond functionalization. In particular, we turned our attention to the 2-bromo-3,3,3-trifluoropropene (BTP), an inexpensive fluorinated reagent coming from industry waste, used as a potential halon replacement for fire suppression and as a fluorinated building block in organic synthesis (Chapter 1). The first part of this Ph.D. thesis was dedicated to the development of new methodologies for the direct introduction of a CF3- vinyl moiety onto arenes and olefins by a Pd-catalyzed directed C(sp2)-H bond functionalization with BTP. Then, this approach was extended to the functionalization of α,β-unsaturated esters, although a different reaction pathway is probably involved (Chapter 2). In the second part of this Ph.D. thesis, we developed a new methodology for the direct introduction of the SCF3 group onto arenes and olefins by Pd-catalyzed directed C(sp2)-H bond functionalization using the Munavalli reagent (Chapter 3).

A fundamental characterization of hexafluoroalcohol substituted polynorbornene (HFAPNB) was completed to improve the final photoresist formulation using these materials. In this work, it was found that the dissolution behavior of these materials was controlled by the ability of polymer chains to form hydrogen bonds. This ability to form interchain hydrogen bonds was affected by stereochemical changes in the polynorbornene backbone as molecular weights increase. These observed changes in backbone polynorbornene stereochemistry were accurately modeled using the "helix-kink" theory, first described by Ahmed and Ludovice. It was found that several material properties altered the interchain hydrogen bonding within these materials, such as the polydispersity, polymerization catalyst, and the polymer film thickness. However, none of these material properties altered the unusual dissolution behavior observed in these materials. To improve the potential formulation of these materials, the interactions between HFAPNB and resist additives were studied. For all tested photoacid generators, it was found that some interchain hydrogen bonding occurred between resist additive molecules and HFA side groups, which retarded the dissolution rate in the formulated material. In particular, one can create a simple resist using unprotected HFAPNB polymer with an iodonium photoacid generator. Finally, a series of norbornene oligomers were evaluated as potential dissolution inhibitors for HFAPNB. It was found that the dissolution rate of HFAPNB can be completely inhibited with dissolution inhibitors at a loading of 15%.

Photoaffinity labeling is a quintessential technique in studying and analyzing the interaction between a ligand and receptor. Diazirines are one of the important photo-labile moieties used in photoaffinity labeling due to their superior photo labeling characteristics. Herein, we report the investigations we conducted with diazirine photolabels on (a) photochemical aspects leading to enhancement of their ambient light stability and (b) equipping them with fluorous tags to enable fluorous enrichment of labeled proteins. Furthermore, we report a pilot study to develop BACE-1 inhibitors, which have potential to be developed into photoaffinity probes. 3-Trifluoromethyl-3-phenyldiazirine offers good selectivity and protection against pseudolabeling but due to its photo lability, it undergoes decomposition even under ambient light. Thus the laboratory handling, including synthesis, of 3-trifluoromethyl-3-phenyldiazirine is cumbersome and restricted under constant darkness. Herein, we have designed, synthesized and evaluated two photolabels with enhanced stability to ambient light conditions in addition to the good selectivity and protection against pseudolabeling as offered by 3-trifluoromethyl-3-phenyldiazirine. It was also found that the aqueous solubility, a vital physical property for a photolabel, was also improved in the modified ambient light stable photolabels. Fluorous tags have found wide use in synthetic applications; herein we explore the possibility of its application in photoaffinity studies. We designed, synthesized and conducted photoactivation studies on two fluorous diazirine photolabels. The photoactivation studies unraveled an unanticipated photoreaction when the fluorous tag was directly connected to the diazirine ring, yielding a fluorous alkene. The more practical photolabel of the two was chosen as the target specific photoaffinity labeling moiety for fluorous proteomics. Upon conducting photolabeling experiments under various conditions, we found that the strong hydrophobic character of the fluorous tag renders the photoaffinity label insoluble in aqueous solutions and significantly alters the binding mode and affinity of the photoaffinity label to its target receptor. A library of 1,3-disubstituted 2-propanols was combinatorially prepared and tested as small molecule inhibitors of β-secretase (BACE-1). The initial screening of the 1,3-disubstituted 2-propanol library revealed a few low micromolar inhibitors for BACE-1. The compound that showed the best activity was chosen for further SAR studies, which resulted in a potent BACE-1 inhibitor with nanomolar inhibition. Investigation on the selectivity of these compounds for BACE-1 inhibition over cathepsin D revealed that these compound series possess very high selectivity. Furthermore, the physicochemical properties study showed that these compounds possessed the calculated parameters advantageous to cross the blood-brain barrier (BBB).

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.

MSc (Chemistry) / Department of Chemistry / The corrosion potential of three ionic liquids (ILs) namely, 5-(Trifluoromethyl)dibenzothiophenium tetrafluoroborate (TDTB), 5-(Trifluoromethyl)dibenzothiophenium trifluoromethanesulfonate (TDTM) and 1-Ethyl-3-methylimidazolium ethyl sulfate [EMIM][ESO4] was studied for mild steel and zinc corrosion in 1.0 M hydrochloric acid using electrochemical, spectroscopic and gravimetric techniques. The studied ILs showed appreciable inhibition efficiencies at the considered concentration range. The highest inhibition efficiencies were observed at 30°C when inhibitor concentration was 8.0 × 10-2 M. The gravimetric data revealed that inhibition efficiencies decreased with an increase in temperature, the lowest inhibition efficiencies for mild steel and zinc were observed at 50°C. The potentiodynamic polarization results indicated that all three inhibitors are mixed-type inhibitors, with TDTM being a predominantly anodic inhibitor. The orders of inhibition efficiency at 8.0 × 10-2 M were TDTM > TDTB > [EMIM][ESO4] and TDTB > TDTM > [EMIM]ESO4] for mild steel and zinc, respectively. All inhibitors showed superior performance in mild steel than in zinc. The adsorption of the studied ILs on mild steel and zinc obeyed the Langmuir adsorption isotherm. The Gibbs free energy of adsorption (ΔG°ads) indicated that the adsorption process was spontaneous, and that corrosion inhibition occurred by a physical adsorption process. Surface morphology analysis through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) revealed a great improvement in the surface morphologies of mild steel and zinc specimens in the inhibited systems. The Fourier transform infrared spectroscopy studies confirmed the chemical interactions between the metal surface and the ILs. This is observed by means of the disappearance of characteristic absorption bands in the adsorption film FTIR spectra. / NRF

A microwave reactor was used to synthesize a series of novel 3,6-disubstituted or 3-substituted pyrazolo[1,5-a]pyrimidines in a total of 1 hour reaction time over 3 steps. The products were obtained in good to excellent yields (34-92%, ave = 52%) using a straightforward synthesis starting with the reaction of dimethylformamide-dimethylacetal with commercially available aryl acetonitriles (120C, 20 min). This was followed by treatment with H2NNH2 • HBr (120C, 20 min), and then reacted with either 1,1,3,3-tetramethoxypropane or a 2-aryl-substituted malondialdehydes (120C, 20 min). The resulting product was either collected on a sintered glass funnel or purified via column chromatography. The compounds were screened for anti-cancer activity against A2780 Ovarian and/or MCF7 breast cancer cell lines in vitro. The most active compounds were the 3-(4-(trifluoromethyl)phenyl)-6-[4-(2-(piperidin-1-yl)ethoxy]phenyl analogue and the 3-(2-fluorophenyl)-6-[4-(2-(4-methylpiperzin-1-yl)ethoxy]phenyl analogue, exhibiting EC50 values of 0.84 and 0.52 M respectively, which is 2-3 times more potent than Dorsomorphin. Several of the derivatives also showed promising activities against several viruses of emerging concern, including HBV, MERS Coronavirus, Zika, and Ebola. Use of a microwave reactor to synthesize N’-aryl/(alkyl) substituted N-[(4-hydroxy-6-phenyl)pyrimidin-2-yl]guanidines or N-[(4-hydroxy-6-trifluoromethyl)pyrimidin-2-yl]guanidines from the corresponding cyanamides with alkyl/aryl amines was achieved in good to excellent yields (39-96%, ave = 62%) in 10 minutes at 120C using only 1 equivalent of amine. Work-up was exceptionally simple, and involved collecting precipitated solids on a sintered glass funnel and washing with cold 2-propanol. Products were obtained in analytically pure form and required approximately 1 hour to prepare, start to finish. Compounds in this series showed early promise as potential inhibitors of A2780 Ovarian cancer, in vitro.

Malaria continues to cause significant mortality in sub-Saharan Africa and elsewhere, and existing vector control measures are being threatened by growing resistance to pyrethroid insecticides. With the goal of developing new human-safe, resistance-breaking insecticides we have explored several classes of acetylcholinesterase inhibitors. In vitro assay studies demonstrate that tri- and difluoromethyl ketones can potentially inhibit An. gambiae AChE (AgAChE). These compounds inhibit the enzyme by making a covalent adduct with the catalytic serine of AChE. Trifluoromethyl ketones however are poor inhibitors of the G119S resistant mutant of AgAChE. However difluoromethyl ketones can inhibit G119S AgAChE and compound 3-10g showed an IC₅₀ value of 25.1 nM after 23h incubation time. Despite this potent inhibition of AgAChE, the tri-, di-, and (mono)fluoroketones showed very low toxicity to An. gambiae, perhaps due to hydration and rapid clearance. In an attempt to improve An. gambiae toxicity, oximes and oxime ethers of these compounds were prepared as potential prodrugs. These structures identified trifluoromethyl ketone oxime 3-2d as a potent toxin against both wild-type (G3-strain) and a multiply resistant (Akron) strain of An. gambiae. This compound is within 3-fold of the toxicity of propoxur to wild type An. gambiae (LC₅₀ values of 106 and 39 µg/mL, respectively). Most significantly, 3-2d was much more toxic than propoxur to multiply-resistant (Akron) strain An. gambiae (LC₅₀ = 112 and >5,000 µg/mL, respectively). However, thus far we have not been able to link the toxicity of these compounds to a cholinergic mechanism. Pre-incubation studies suggest that significant hydrolysis of these compounds to TFKs does not occur over 22 h at pH 7.7 or 5.5. The mechanism of action of 3-2d remains unknown. Our enzyme inhibition studies have demonstrated that 3-2d does not hydrolyze to the trifluoromethyl ketone 2-9d at pH 7.7. The high Akron toxicity of 3-2d and poor inhibition of G119S AgAChE by 2-9d argue against enzyme mediated conversion of 3-2d to 2-9d within the mosquito. Thus, we can rule out an AChE inhibition mechanism for toxicity. Additional experiments by our collaborator (Dr. Jeffrey Bloomquist, University of Florida) also rule out inhibition of mitochondrial respiration or agonism of the muscarinic acetylcholine receptor. Future work will address other potential insecticidal modes of action. / Ph. D.

Asymmetric hydrogenation has emerged as a versatile methodology to obtain a wide range of chiral precursors. This thesis focused on the synthesis of new chiral ligands and the expansion of the substrate scope of asymmetric hydrogenations. Paper I described the synthesis and evaluation of N,P-ligands for the Ir-catalyzed hydrogenations of unfunctionalized olefins. The substrate scope of Ir-catalyzed asymmetric hydrogenations is limited to a narrow range of “test” olefins. The foremost focus of this thesis was to expand the substrate scope of Ir-catalyzed asymmetric hydrogenations. Papers II and III disclosed the potential of the N,P-ligated Ir complexes in hydrogenation of the enol phosphinates. This substrate class is attractive because the hydrogenated products are chiral alkylphosphinates that can be transformed into chiral alcohols and chiral phosphines without sacrificing enantiopurity. A wide range of enol phosphinates were hydrogenated to excellent conversions and enatioselectivities. The hydrogenation of purely alkyl-substituted enol phosphinates in very high conversions and ee values was emphasized in these studies. Paper IV described the investigation of unfunctionalized enamines as substrates in Ir-catalyzed hydrogenation studies. The hydrogenation results and structural limitations of the substrates are presented. Paper V described the asymmetric hydrogenation of diphenylvinylphosphine oxides, di- and trisubstituted vinyl phosphonates. The hydrogenation of diphenylvinylphosphine oxides gives direct access to protected chiral phosphines. The hydrogenated products of vinylphosphonates are highly synthetically useful in pharmaceutical and material chemistry. Hydrogenation of E/Z mixtures of carboxyethyl vinylphosphonates with perfect enantioselectivities was striking in these studies. In paper VI, we have reported the development of a new, highly enantioselective synthetic route to building blocks with CF3 at the chiral center. Several functionalized and unfunctionalized CF3-substituted olefins were hydrogenated with varied degree of success. This methedilogy is useful in the formation of chiral fluorine-containing molecules for a wide range of applications. Paper VII described the hydrogenation of imines using the phosphine-free Cp*Ru/diamine complexes. Chiral version of this reaction was also examined. Despite the modest results, this is the first study to use phosphine-free Cp*Ru/diamine complexes as catalysts for the reduction of C=N double bonds.