Made available in DSpace on 2014-10-09T12:43:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:02Z (GMT). No. of bitstreams: 1 06438.pdf: 3544819 bytes, checksum: 626dbfb5d984317f4ef60a7e9d45aa5c (MD5) / Dissertacao (mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

In this thesis new synthetic routes towards perfluorinated compounds are described, as well as their radiolabelling with fluorine-18, with the aim of application in pharmaceutically interesting targets. Part A investigates late-stage fluorination, i.e. retrosynthetic C–F bond disconnections. A silver catalysed electrophilic fluorodecarboxylation of fluorinated carboxylic acids for the formation of difluoromethyl-, trifluoromethyl-, and pentafluoroethylarenes is developed and transferred to a radiochemistry setting using [¹⁸F]Selectfluor bis(triflate). Part B explores late-stage perfluoroalkylation via cross-coupling strategies. The use of visible light-mediated ruthenium catalysis is investigated for the radical trifluoromethylation and pentafluoroethylation of vinyl- and alkynylsilanes and alkynes. Finally, the first generally applicable copper-mediated cross-coupling of Ruppert-Prakash-like aryl(tetrafluoroethyl)trimethylsilanes (ArCF2CF2SiMe3) is presented.

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Made available in DSpace on 2014-10-09T12:41:27Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:27Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:43:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:02Z (GMT). No. of bitstreams: 1 06438.pdf: 3544819 bytes, checksum: 626dbfb5d984317f4ef60a7e9d45aa5c (MD5) / Dissertacao (mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:29:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:23Z (GMT). No. of bitstreams: 1 00374.pdf: 1851667 bytes, checksum: eb55ab298cfe6ea72073a36c84226d72 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Energia Atomica - IEA

Made available in DSpace on 2014-10-09T12:41:27Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:27Z (GMT). No. of bitstreams: 0 / O radiofármaco FLT-18F é um análogo do nucleosídeo timidina e um promissor marcador da proliferação tumoral para imagens em PET. A síntese deste radiofármaco não é simples e, muitas vezes, apresenta baixos rendimentos. Este radiofármaco já vem sendo estudado há alguns anos, porém, não há produção, nem estudos clínicos, no Brasil. O estudo do processo produtivo e a sua adequação às diretrizes de Boas Práticas de Fabricação (ANVISA) são de extrema importância. Este trabalho teve como objetivo estudar a síntese deste radiofármaco, avaliar os métodos de controle de qualidade que serão utilizados na rotina de produção futura, realizar estudos de citotoxicidade, estudos de biodistribuição e imagens PET em animais, contribuindo para o desenvolvimento e elaboração do protocolo de validação de processo e estabelecimento das metodologias analíticas a serem utilizadas durante a rotina de produção. Inicialmente, foi estudada a síntese e produção do produto FLT-18F, com a avaliação de três temperaturas diferentes de marcação, a m de vericar o comportamento do rendimento radioquímico e a estabilidade do produto nal. Os estudos de metodologia analítica compreenderam as análises de identicação radionuclídica, determinação dos pers cromatográcos, pureza radioquímica, solventes residuais e pH. Estudos in vitro do FLT- 18F de internalização e citotoxicidade também foram feitos. Nos estudos in vivo, avaliou-se a farmacocinética, biodistribuição em animais sadios e em animais com modelos tumorais, além de imagens PET/CT de animais com melanoma. O produto nal apresentou alta pureza radioquímica e mostrou-se estável por até 10 horas após a síntese, porém obteve-se um rendimento radioquímico relativamente baixo, conforme descrito na literatura. As metodologias analíticas testadas mostraram-se adequadas para o uso no controle de qualidade do FLT-18F. Nos estudos in vitro o FLT-18F apresentou uma signicativa porcentagem de ligação às células tumorais e a molécula não radiomarcada não foi considerada tóxica para estas células estudadas. A biodistribuição e as imagens apresentaram resultados compatíveis com o esperado. As contribuições para a validação de processo foram satisfatórias e auxiliarão na validação futura do processo produtivo do radiofármaco em estudo. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T03:22:31Z (GMT). No. of bitstreams: 1 Franco_MiltonBatista_D.pdf: 5657387 bytes, checksum: 9e99cd3d82f91d042547d9255ae0b274 (MD5) Previous issue date: 2006 / Resumo: Este trabalho teve como objetivo determinar os parâmetros f, a, índice espectral e temperatura de nêutrons na mesa (parada e girando) e no tubo central do REATOR IPR-R1, visando a aplicação da técnica de ativação neutrônica paramétrica ko. É um método monopadrão de análise química por ativação neutrônica de aplicação bastante geral que elimina preparações tediosas de curvas de padrões, com capacidade analítica quantitativa multielementar e com uma exatidão comparável ao método relativo clássico¿Observação: O resumo, na íntegra poderá ser visualizado no texto completo da tese digital / Abstract: This research intended to determine the nuclear parameters a, f, spectral index and neutron temperature in several irradiations positions of the TRIGA MARK I IPR-R1 reactor, for use on the parametric method ko in the CDTN. Ko is a monostandard method of neutron activation analysis. It is, on the whole, experimentally simple, flexible and an important tool for accurate and convenient standardization in instrumental multi-element analysis...Note: The complete abstract is available with the full electronic digital thesis or dissertations / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Positron emission tomography (PET) is an important and powerful nuclear imaging modality and is essential in a range of medical fields. A suitable radiotracer must be identified in order for PET imaging to provide high quality and quantifiable data about the pathology. This includes the design and implementation of optimal radiochemistry that will reliably deliver the radiotracer that can answer the pertinent biological questions being asked. PET can be used to study the biological processes which are involved in pain perception and inflammatory responses that can occur in a number of chronic and acute conditions. This thesis aims to demonstrate how PET radiochemistry can enhance our knowledge of these biological processes and permits access to the underlying molecular mechanisms behind pain and inflammation. This thesis has been written in an alternative format, comprising the different areas which have been investigated. The work encompasses the study of the endogenous opioid system using the opioid receptor antagonist [11C]diprenorphine. This includes the design and automation of [11C]diprenorphine radiochemistry followed by the development of a method to reliably analyse its metabolism. Finally the application of [11C]diprenorphine in a clinical PET study, investigating opioid receptor occupancy by endogenous opioids as well as up-regulation of opioid receptors in the brain, is described. In the study of inflammation a pro-inflammatory cytokine, recombinant human interleukin-1 receptor antagonist (rhIL-1RA), was radiolabelled with novel 18F radiochemistry permitting pharmacokinetic study in pre-clinical models. This is followed by the design of a new technique to radiolabel white blood cells with 89Zr for quantifiable cell trafficking with PET. For this technique, chitosan nanoparticles are used to deliver the radio-metal cargo into white blood cells with a proposed application in inflammatory models. The process of chitosan nanoparticle construction is described alongside development of a procedure that is optimised for use in the proposed application. This thesis covers a variety of topics illustrating the contribution of PET radiochemistry in the area of pain and inflammation. The synergy between identification of new biological targets and development of radiotracers and radiolabelling strategies ensure PET radiochemistry will continue to contribute to our knowledge of pain and inflammation and aid understanding of its role in countless medical conditions.

The nucleotide 2'-deoxythymidine 5'-monophosphate (thymidylate, dTMP) is phosphorylated twice to become a substrate for DNA polymerases, which copy a cell’s genetic information in advance of cell division. The main route to dTMP is mediated by the enzyme thymidylate synthase (TSase) and goes through 2'-deoxyuridine 5'-monophosphate (dUMP); dUMP’s heterocyclic aromatic pyrimidine ring loses a proton from its C5 position and gains a methylene and a hydride from the other reactant, methylene tetrahydrofolate (MTHF). In general, intricate knowledge of an enzyme’s mechanism can yield insight that leads to the development of precision-targeted inhibitors tailored exactly to thymidylate synthase. In fact, even more careful targeting could be achievable: Although E. coli TSase has served as a model system, investigators have increasingly been directing their lines of inquiry toward human TSase. A general enzymatic catalytic cascade is complex, comprising substrate binding, the chemical steps and product release; typically, the product release step is rate-limiting. TSase, however, is partially rate-limited by the chemistry portion of the process. The enzymatic mechanism has been considered for decades, yet recently has undergone a reassessment. After substrate binding – for which there is strong evidence for preference to dUMP as the first ligand in the wild-type E. coli enzyme – the important events are methylene transfer from MTHF to dUMP, proton abstraction and hydride transfer. The last of these – hydride transfer – is irreversible and rate-limiting (to a large degree without Mg2+, and to a small but noticeable degree with Mg2+). The studies described here are aimed at three therapeutically relevant questions: (a) determining the extent of negative charge accumulation at the O4 position of the hydride transfer acceptor; (b) expanding knowledge of the differential properties of E. coli and human TSase; and (c) gaining insight into the molecular origin of the drug resistance seen in a clinically relevant human TSase mutant. The properties touched on in this work include steady-state kinetics; inhibition constants toward 5-fluoro dUMP, substrate binding sequence and the temperature dependency of intrinsic hydride transfer kinetic isotope effects (KIEs). Intrinsic KIEs are a specialized measurement that permits the investigator to examine a particular hydrogen transfer step in isolation; it is achieved by labeling the bond to hydrogen broken in the reaction with protium (1H, also written as H), deuterium (2H, also written as D) or tritium (3H, also written as T). The latter is radioactive. The reaction is conducted with a mixture of two hydrogen isotopes at a time, and the extent to which the heavier isotope is disfavored against reaction is assessed; this covers multiple steps. Heavier isotopes directly participating in a chemical step react slower both because of zero-point vibrational energies if a semi-classical view is taken and because of the mass-dependence of tunneling probabilities if a quantum-mechanical view is taken. Each of the two-way isotopic comparisons mentioned above furnishes an observed KIE for that competition between two isotopes. Mathematical combination of two isotopic comparisons cancels out the effect of isotopically insensitive steps and provides rich insight into the hydride transfer alone. The ultimate result is the ratio of rate constants for the isotopologues; this ratio’s magnitude and variation with temperature report on the compactness of the active site and its resistance to thermal fluctuation, respectively. Our results reveal a possible role for E. coli asparagine 177 (N177) in the hydride transfer transition state (TS) stabilization, as revealed by its disruption in the aspartate mutant, N177D. This disruption was found to be alleviated to a high extent when the substrate was changed to dCMP, consistent with the N177 stabilizing partial negative charge at the TS for hydride transfer. This has drug design implications. Our work on human TSase underscores slightly weaker substrate binding preference, insensitivity to Mg2+ and mild alteration of hydride transfer TS when compared with E. coli TSase. Finally, analysis of the Y33H mutant of human TSase – the affected residue being remote from the active site – indicated the drug resistance was because of a higher inhibition constant for 5F-dUMP and that the hydride transfer step is disrupted, with a wider variation among donor-acceptor distances (between the two carbons involved in the hydride transfer at the TS for that step). Other researchers’ crystallographic evidence reveals greater positional uncertainty for a set of active-site side chains in the E. coli equivalent mutant. In totality, the data available implicate enzyme motions as relevant to drug binding and to catalysis for human TSase. In summary, the research described herein enriches the understanding of several aspects of the behavior of multiple TSase variants – the overall performance as seen via steady-state kinetics; the pattern of substrate binding as seen with observed KIEs for the proton abstraction step; and the efficiency of active site preparation for hydride transfer as evidenced in the temperature dependency of intrinsic hydride transfer KIEs.