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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

Policetídeos e lignóides do tegumento de virola elongata warb. (Myristicaceae) / Poliketides and lignoids of the Tegument from Virola elongata (Spr. ex Benth) Warb.

Kato, Massuo Jorge 16 March 1984 (has links)
A presente dissertação descreve o isolamento e elucidação estrutural de alguns constituíntes químicos do tegumento de V. elongata, espécie envolvida em usos etnofarmacológicos. 0 extrato clorofórmico forneceu além de ésteres alifáticos e triglicerídeos dois policetídeos do tipo diarilalcanoílicos: 1-(2\',6\'- Dihidroxi-4\'-metoxifeni1)-12-fenil-dodecan-1-ona (inédito) e 1-(2\',4\',6\'- Trihidroxi-3\',4\'-dihidrofeni1)-11-fenil-undecan-1-ona (conhecido) ; três lignanas furofufurânicas: (1R,2S,5R,6R)-6-(3\',4\'-Dimetoxifeni1)-2-(3\",4\"-metilenodioxifeni1)-3,7-dioxabiciclo‌3.3.0‌ octano (fargesina); (1R,2S,5R,6R)-2,6-Bis-(3\",4\" -dimetoxifeni1)-3,7-dioxabiciclo- ‌3.3.0‌ octano (epieudesmina) e (1R,2S,5R,6S)-2,6-Bis-(3\",4\" -dimetoxifenil)-3,7-dioxabiciclo ‌3.3.0‌ octano (eudesmina); e duas neolignanas tetraidrofurânicas: (1S,2S,5R,6R)-1-Metil - 2-(3\",4\"-metilenodioxifeni1)-5-(α-hidroxi-3\" 1,4\'\"-dimetoxibenzil)-tetraidrofurano (inédita) e (15,2S,5R,6R)-1-Metil-2-(3\",4\"-dimetoxifeni1)-5-(α-hidroxi-3\'\",4\'\"-dimetoxibenzil)-tetraidrofurano (magnostelina A). 0 isolamento dos constituíntes químicos foi baseada em técnicas cromatográficas e a elucidação estrutural em métodos espectrométricos usuais (UV, IV, DRO, RMN de 1H e de 13C). A comprovação da estrutura do policetídeo Ve-6 foi baseada na aromatização por desidratação em meio ácido. A determinação da configuração relativa das neolignanas tetreidrofurânicas foi baseada em estudo envolvendo o reagente de deslocamento Eu(fod)3. A determinação da configuração absoluta foi baseada na conversão em uma neolignana tetralínica e comparação de sua curva de DRO com compostos modêlos. / The present dissertation describe isolation and structural elucidation of some chemicals constituents of tegument from V. elongata, involved in ethnopharmacology uses. The chloroform extract afford besides aliphatics esthers and triglycerides, two poliketides of the diarylalkanoyl type: 1-(2\',6\'-Dihydroxypheny1)-12-dodecan-l-one and 1-(2\',4\',6\'-Trihydroxy-3\',5\'-dihydropheny1)-11-phenyl-undecan-1-one, the former is unknown and the latter is known; three furofuranic lignans type: (1R, 2S, 5R, 6R) -6- (3\',4\'-Dimethoxypheny1)-2-(3\",4\" -methylenedioxypheny1)-3,7-dioxabicycle‌3.3.0‌ octane (fargesin); (1R,2S,5R,6R)-2,6-Bis-(3\",4\"-dimethoxypheny1)-3,7-dioxabicycle‌3.3.0‌octane (epieudesmin) and (1R,2S,5R,6S)-2,6-Bis-(3\",4\" -dimethoxypheny1)-3,7-dioxabicycle‌3.3.0‌ octane (eudesmin); and two neolignans of the tetrahydrofuranic type:(1S,2S,5R,6R)-1-Methy1-2-(3\",4\" -methylenedioxypheny1)-5-(α-hydroxy-3\'\",4\'\" -dimethoxybenzy1)-tetrahydrofuran (unknow) and (1S,2S,5R,6R)-1-Methy1-2-(3\",4\" -dimethoxypheni1)-5-(α-hydroxy-3\'\",4\'\"-dimethoxybenzy1)-tetrahydrofuran (magnostelin A). Isolation of chemical constituents was based on chromatographic techniques and structural determination on usual spectrometric methods (UV, IR, MS, ORD, 1H and 13C NMR). Poliketyde skeleton was elucidated by acid catalized dehydration yielding a diarylic compound. The relative structure of tetrahydrofuranic neolignans was based in lanthanide induced shift reagent. The absolute configuration was based on chemical transformation to tetralinic neolignan and comparison of its ORD curve with model compounds curves.
2

Policetídeos e lignóides do tegumento de virola elongata warb. (Myristicaceae) / Poliketides and lignoids of the Tegument from Virola elongata (Spr. ex Benth) Warb.

Massuo Jorge Kato 16 March 1984 (has links)
A presente dissertação descreve o isolamento e elucidação estrutural de alguns constituíntes químicos do tegumento de V. elongata, espécie envolvida em usos etnofarmacológicos. 0 extrato clorofórmico forneceu além de ésteres alifáticos e triglicerídeos dois policetídeos do tipo diarilalcanoílicos: 1-(2\',6\'- Dihidroxi-4\'-metoxifeni1)-12-fenil-dodecan-1-ona (inédito) e 1-(2\',4\',6\'- Trihidroxi-3\',4\'-dihidrofeni1)-11-fenil-undecan-1-ona (conhecido) ; três lignanas furofufurânicas: (1R,2S,5R,6R)-6-(3\',4\'-Dimetoxifeni1)-2-(3\",4\"-metilenodioxifeni1)-3,7-dioxabiciclo‌3.3.0‌ octano (fargesina); (1R,2S,5R,6R)-2,6-Bis-(3\",4\" -dimetoxifeni1)-3,7-dioxabiciclo- ‌3.3.0‌ octano (epieudesmina) e (1R,2S,5R,6S)-2,6-Bis-(3\",4\" -dimetoxifenil)-3,7-dioxabiciclo ‌3.3.0‌ octano (eudesmina); e duas neolignanas tetraidrofurânicas: (1S,2S,5R,6R)-1-Metil - 2-(3\",4\"-metilenodioxifeni1)-5-(α-hidroxi-3\" 1,4\'\"-dimetoxibenzil)-tetraidrofurano (inédita) e (15,2S,5R,6R)-1-Metil-2-(3\",4\"-dimetoxifeni1)-5-(α-hidroxi-3\'\",4\'\"-dimetoxibenzil)-tetraidrofurano (magnostelina A). 0 isolamento dos constituíntes químicos foi baseada em técnicas cromatográficas e a elucidação estrutural em métodos espectrométricos usuais (UV, IV, DRO, RMN de 1H e de 13C). A comprovação da estrutura do policetídeo Ve-6 foi baseada na aromatização por desidratação em meio ácido. A determinação da configuração relativa das neolignanas tetreidrofurânicas foi baseada em estudo envolvendo o reagente de deslocamento Eu(fod)3. A determinação da configuração absoluta foi baseada na conversão em uma neolignana tetralínica e comparação de sua curva de DRO com compostos modêlos. / The present dissertation describe isolation and structural elucidation of some chemicals constituents of tegument from V. elongata, involved in ethnopharmacology uses. The chloroform extract afford besides aliphatics esthers and triglycerides, two poliketides of the diarylalkanoyl type: 1-(2\',6\'-Dihydroxypheny1)-12-dodecan-l-one and 1-(2\',4\',6\'-Trihydroxy-3\',5\'-dihydropheny1)-11-phenyl-undecan-1-one, the former is unknown and the latter is known; three furofuranic lignans type: (1R, 2S, 5R, 6R) -6- (3\',4\'-Dimethoxypheny1)-2-(3\",4\" -methylenedioxypheny1)-3,7-dioxabicycle‌3.3.0‌ octane (fargesin); (1R,2S,5R,6R)-2,6-Bis-(3\",4\"-dimethoxypheny1)-3,7-dioxabicycle‌3.3.0‌octane (epieudesmin) and (1R,2S,5R,6S)-2,6-Bis-(3\",4\" -dimethoxypheny1)-3,7-dioxabicycle‌3.3.0‌ octane (eudesmin); and two neolignans of the tetrahydrofuranic type:(1S,2S,5R,6R)-1-Methy1-2-(3\",4\" -methylenedioxypheny1)-5-(α-hydroxy-3\'\",4\'\" -dimethoxybenzy1)-tetrahydrofuran (unknow) and (1S,2S,5R,6R)-1-Methy1-2-(3\",4\" -dimethoxypheni1)-5-(α-hydroxy-3\'\",4\'\"-dimethoxybenzy1)-tetrahydrofuran (magnostelin A). Isolation of chemical constituents was based on chromatographic techniques and structural determination on usual spectrometric methods (UV, IR, MS, ORD, 1H and 13C NMR). Poliketyde skeleton was elucidated by acid catalized dehydration yielding a diarylic compound. The relative structure of tetrahydrofuranic neolignans was based in lanthanide induced shift reagent. The absolute configuration was based on chemical transformation to tetralinic neolignan and comparison of its ORD curve with model compounds curves.
3

Síntese formal dos policetídeos bicíclicos salinecetais A e B / Formal synthesis of the biciclic polyketides saliniketals A and B

Perez, Carla Cristina, 1979- 20 August 2018 (has links)
Orientador: Luiz Carlos Dias / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-20T16:20:14Z (GMT). No. of bitstreams: 1 Perez_CarlaCristina_D.pdf: 5128114 bytes, checksum: d3cf5087b543e1096ea7da56cdaadc47 (MD5) Previous issue date: 2012 / Resumo: Os salinecetais A e B foram isolados em 2007 por Fenical e colaboradores a partir da actinobactéria marinha Salinispora arenicola, e mostraram ser importantes alvos na quimioprevenção do câncer como inibidores da ornitina descarboxilase. Concluímos a síntese do fragmento avançado C-4/C-17 (19) envolvendo 19 etapas em 5,5% de rendimento global a partir do éster de Roche (rota linear mais longa). No decorrer deste trabalho algumas mudanças de estratégia se fizeram necessárias, estando sempre voltadas à procura da rota sintética mais criativa e eficiente. Foram utilizadas como etapas chave na rota sintética principal, reações aldólicas do tipo syn seletivas para a preparação do aduto 139, bem como reação aldólica de dupla diastereodiferenciação na preparação de 134b. Uma reação de Grignard estereocontrolada pelo substrato foi determinante na preparação de 169, seguido de uma ciclização intramolecular do tipo Wacker para formação do biciclo espirocetal presente em 29. A reação de homologação de Seyferth-Gilbert foi usada na preparação do alcino 187 e uma syn-hidroestanilação converteu o mesmo na estanana vinílica 19. Esse resultado permitiu a determinação inequívoca da estereoquímica dos centros formados por comparação com os dados obtidos nesse trabalho com os da literatura, além dessa rota permitir, a princípio, a obtenção dos mesmos fragmentos em escalas maiores / Abstract: The saliniketals A (1) and B (2) were isolated in 2007 by Fenical and coworkers from Salinispora arenicola and showed to be important inhibitors of ornithine decarboxylase. We concluded the synthesis of C-4/C-17 fragment (19) after 19 steps in 5.5% overall yield from Roche ester (longest linear sequence). This work was always focused on the search for the more creative and efficient synthetic route. The key steps involved an efficient syn-aldol reaction for the preparation of adducts 139 and a double diastereo-differentiating aldol reaction for the preparation of 134b. Substrate controlled Grignard reaction provide 169, and an intramolecular Wacker-type cyclization established the bicyclic spiroketal in 29. The Seyferth-Gilbert homologation was used in the preparation of alkyne 187 and a syn-hydrostannation provided the vinyl stannane 19. This result allowed the unequivocal determination of the stereochemistry for all stereocenters formed by comparison with data obtained from the literature. We are able to conclude a formal total synthesis of saliniketals A and B and the synthetic route is, in principle, amenable to a large scale synthesis / Doutorado / Quimica Organica / Doutora em Ciências
4

Etude biosynthétique des dérivés polykétides PKS-NRPS de type pyrrocidine chez Acremonium zeae / Biosynthetic study of pyrrocidine related compounds, polyketides PKS-NRPS in Acremonium zeae

Ear, Alexandre 13 October 2014 (has links)
Les composés de type pyrrocidine sont des polykétides PKS-NRPS possédant des activités biologiques intéressantes comme antifongique ou antibiotique. La synthèse totale de ces composés est un réél challenge comme il est constitué de 10 centres chiraux et d'un macrocycle complexe. L'étude de leur biosynthèse pourrait être d'une aide importante afin de comprendre le mécanisme de formation de cette structure spéciale, et en particulier l'étape de la cyclisation complexe.Le précurseur linéaire de ces polykétides étant composé par une chaine nonakétide (partie PKS) et d'une L-tyrosine (partie NRPS), des hypothèses sur leur biosynthèse ont été émises dans cette thèse. Des expériences d'incorporation de précurseurs marqués ou non vont être réalisées dans différents milieux de culture en vue d'obtenir des informations sur cette biosynthèse, et plus précisément le passage du précurseur linéaire vers la structure polycyclique complexe. En parallèle, des supplémentations des cultures d'A. zeae avec des dérivés de la tyrosine seront faites dans le but d'obtenir des analogues pouvant avoir des activités biologiques nouvelles ou meilleures que les pyrrocidines. / Pyrrocidine and its related compounds are PKS-NRPS polyketides having biological interests such as antifungal or antibiotic activities. The total synthesis of these entities has been challenging since the family of hirsutellone is composed by 10 chiral centers and a complex macrocycle. Studying the biosynthesis of these compounds can be an asset for the comprehension of this special molecular structure, especially for the complex cyclization step. Knowing that the linear precursor of these molecules is constituted by a nonaketide chain (PKS part) and by an L-tyrosine (NRPS part), hypotheses about the biosynthesis of hirsutellone-related compounds have been developed in this thesis. Some incorporation experiments of labeled or unlabeled compounds has been done in different culture media in order to have more information about this biosynthesis, in particular the conversion of the linear precursor into this complex polycyclic structure. In parallel, the supplementation of L-tyrosine derivatives will help us to get some analogs of pyrrocidine which can have new or better activities than natural products.

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