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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Reações de oxidação e hidrolise por microrganismos nos metodos de biocatalise e de biorremediação / Reaction of oxidation and hydrolysis for microorganisms in methods of biocatalysis and bioremediation

Costa, Luiz Antonio Mendonça Alves da 03 July 2005 (has links)
Orientador: Anita Jocelyne Marsaioli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T15:13:44Z (GMT). No. of bitstreams: 1 Costa_LuizAntonioMendoncaAlvesda_D.pdf: 24416441 bytes, checksum: bec02c6b51213d77af83bf869644c046 (MD5) Previous issue date: 2005 / Resumo: O presente trabalho foi dividido em dois projetos: a avaliação do potencial biocatalítico de microrganismos isolados da abelha Trigonna sp e o estudo de biorremediação de ambiente contaminado por Alachlor®. A atividade catalítica de oxidação de sulfeto e a hidrólise de éster sulfínico de 12 linhagens de fungos foi avaliada durante a primeira parte deste trabalho, dentre das quais, 8 linhagens foram isoladas do corpo da abelha Trigonna sp em trabalhos anteriores do nosso grupo. Os melhores microrganismos na oxidação enantiosseletiva do etil fenil sulfeto foram os Fungo CCT 5553 e Cladosporium sp. CBMAI 0210 que produziram o (S)-etil-fenil-sulfóxido (ee > 99%) e (R)-etil-fenil-sulfóxido (ee 97%), respectivamente. O (S)-etil-fenil-sulfóxido (ee > 92%) foi aplicado na síntese da S-(+)-4-metil-3-heptanona, feromônio de alarme da formiga do gênero Atta, mas uma racemização durante a eliminação do grupo sulfinila impossibilitou a síntese total. Para a resolução enzimática de (±)-benzenossulfinato de cicloexila foi selecionado os fungos Penicillium sp. CBMAI 0208 e Aspergillus ochraceus CBMAI 0211 ambos fornecendo os produtos com excessos enantioméricos > 99%. Na segunda etapa, avaliou-se a capacidade de degradação do pesticida Alachlor® de 6 linhagens de bactérias (Streptomyces sp.) e as estruturas dos produtos de degradação foram sugeridas baseados em seus padrões de fragmentação. Entre esses 8-etil-quinolina e N-metil-8-etil-indol nunca foram citados nos estudos de biodegradação do Alachlor®. / Abstract: The work presented in this thesis is divided into two projects: the evaluation of the biocatalytic potential of microorganisms isolated from Trigonna bee and those deposited in two brazilian collections and bioremediation of Alachlor contamined soil. The sulfide oxidation and sulfinic esters hydrolysis catalytic activity was screened using 12 different fungi strains, 8 of which were previously isolated from a Trigonna sp. bee. The best microorganisms for the enantioselective oxidation of ethyl phenyl sulfide were Fungus CCT 5553 and Cladosporium sp. CBMAI 0210 WHICH PRODUCED (R)-ethyl phenyl sulfoxide (ee 97%) and (S)-ethyl phenyl sulfoxide (ee > 99%) respectively. The chiral (S)-ethyl phenyl sulfoxide which was applied in the synthesis of S-(+)-4-methyl-3-heptanone, ant alarm pheromone (genus Atta), of but racemization during sulfinyl group elimination step precluded the total asymmetric synthesis. For the enzymatic resolution of the cyclohexyl (±)-benzenosulfinate we have selected Penicillium sp. CBMAI 0208 and Aspergillus ochraceus CBMAI 0211 both with the capacity of resolving the sulfinate in over 99 enantiomeric excess. In the second part, the Alachlor® degradation potential of 6 bacterium strains (Streptomyces sp.) was evaluated and the structures of biodegradation products were suggested based on their mass fragmentation patterns. Among these 8-ethyl-quinoline and N-methyl-8-ethyl-indole have never been mentioned as Alachlor biodegradation products before. / Doutorado / Quimica Organica / Doutor em Quimica
2

Nouveaux accès aux ions sulfinates et sulfénates

Caupène, Caroline 01 December 2005 (has links) (PDF)
Les anions sulfénates (RSO–) et sulfinates (RSO2–) sont des nucléophiles soufrés utiles en synthèse organique. Ils sont des précurseurs respectifs de sulfoxydes et de sulfones (S-alkylation). Les travaux de cette thèse ont permis de mettre au point un accès direct aux sulfinates aliphatiques par oxydation des thiolates analogues. L'oxydant de choix est une N-sulfonyloxaziridine dérivée de la pinacolone. La conversion en sulfones par traitement avec des halogénures d'alkyle a été abordée. Dans un second temps, une méthode de préparation d'ions sulfénates extrêmement flexible a été mise au point. Elle est basée sur une réaction d'élimination conduite sur des sulfoxydes possédant un proton acide en position b. La simplicité de cette méthode ainsi que la facilité de mise en oeuvre ont permis de préparer des ions sulfénates de structures variées. Pour finir, une étude préliminaire de formation d'ions sulfénates à partir de sulfoxydes b-silylés a offert des résultats encourageants en série aromatique.
3

Palladium(II)-Catalysed Heck and Addition Reactions : Exploring Decarboxylative and Desulfitative Processes

Skillinghaug, Bobo January 2016 (has links)
Palladium complexes have the ability to catalyse cross-coupling of two organic moieties through the formation of transient metal-carbon bonds, thus bringing them closer to each other to facilitate the formation of a new bond. Palladium-catalysed coupling reactions are one of the most important carbon-carbon forming reactions available to organic chemists and many of these reactions rely on the reactivity of aryl-palladium complexes. The investigation of new aryl-palladium precursors is thus of great interest, especially as more sustainable and economic methods can be developed. This thesis describes the use of carboxylic acids and sodium arylsulfinates as such new arylating agents. Protocols for microwave-assisted palladium(II)-catalysed decarboxylative synthesis of electron-rich styrenes and 1,1-diarylethenes were developed. However, these transformations had very limited substrate scopes which prompted the investigation of sodium arylsulfinates as alternative arylating agents. These substrates were employed in the microwave-assisted palladium(II)-catalysed desulfitative addition to nitriles, and the substrate scope was demonstrated by combining a wide array of sodium arylsulfinates and nitriles to yield the corresponding aryl ketones. The application of the desulfitative reaction in a continuous flow setup was demonstrated, and aluminium oxide was identified as safe alternative to borosilicate glass as a reactor material. The mechanisms of the decarboxylative and desulfitative transformations were investigated by density functional theory (DFT) calculations. The desulfitative reaction was also investigated by direct electrospray ionization mass spectrometry (ESI-MS), providing further mechanistic insight. Finally, a protocol for the safe and convenient synthesis of a wide range of sodium arylsulfinates was developed.

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