309 resultados para Friedel-Crafts benzylation


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A southern Australian marine sponge, Trachycladus laevispirulifer, has yielded a potent new nematocide with antifungal activity which has been identified as onnamide F (1). The structure for 1 was assigned by detailed spectroscopic analysis and chemical conversion to the methyl ester 2. Onnamide F contains a common structural motif previously described in a number of natural products exhibiting interesting pharmacological activities, including the insect chemical defense agent pederin (3), and the sponge metabolites the onnamides, mycalamides, and theopederins.

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Bioassay-directed fractionation of the EtOH extract of an Oceanapia sp. collected off the northern Rottnest Shelf, Australia, has yielded three novel dithiocyanates, thiocyanatins A (1), B (2a), and C (2b). The structures were determined by detailed spectroscopic analysis and confirmed by total synthesis. In addition to featuring an unprecedented dithiocyanate functionality, thiocyanatins possess an unusual 1,16-difunctionalized n-hexadecane carbon skeleton and are revealed as a hitherto unknown class of nematocidal agents

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Bioassay-directed fractionation of two southern Australian sponges, Phoriospongia sp. and Callyspongia bilamellata, yielded two new nematocidal depsipeptides, identified as phoriospongins A (1) and B (2). The structures of the phoriospongins were determined by detailed spectroscopic analysis and comparison with the previously reported sponge depsipeptide cyclolithistide A (3), as well as ESIMS and HPLC analysis of acid hydrolysates. It is noteworthy that the unique and yet structurally related metabolites 1-3 are found in sponges spanning three taxonomic orders, Poescilosclerida, Haplosclerida, and Lithistida.

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Bioassay-directed fractionation of a Hymeniacidon sp. yielded as nematocidal agents the equilibrating E/Z bromoindole ethyl esters 1 and 2 and corresponding methyl esters 3 and 4. Also isolated for the first time as a natural product was an equilibrating mixture of seco-xanthine formamides, attributed the trivial name hymeniacidin (5). The structure for 5 was assigned on the basis of detailed spectroscopic analysis and total synthesis.

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A search for new antiparasitic agents from a strain of the fungus Aspergillus carneus isolated from an estuarine sediment collected in Tasmania, Australia, yielded the known terrestrial fungal metabolite marcfortine A ( 1) as an exceptionally potent antiparasitic agent. This study also yielded a series of new depsipeptides, aspergillicins A - E ( 2 - 6) and the known terrestrial fungal metabolite acyl aszonalenin ( 7). Marcfortine A ( 1) and acyl aszonalenin ( 7) were identified by spectroscopic analysis, with comparison to literature data. Complete stereostructures were assigned to aspergillicins A - E ( 2 - 6) on the basis of detailed spectroscopic analysis, together with ESIMS analysis of the free amino acids generated by acid hydrolysis, and HPLC analysis of Marfey derivatives prepared from the acid hydrolysate. The peptide amino acid sequence for all aspergillicins was unambiguously assigned by MSn ion-trap ESI mass spectrometry.

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Bioassay directed fractionation of a Raspailia (Raspailia) sp. (Order Poecilosclerida; Family Raspailiidae) collected during scientific trawling operations off the Northern Rottnest Shelf yielded as nematocidal agents the known metabolites, phorboxazoles A (1) and B (2). Further examination revealed the new natural product but known synthetic compound, esmodil (3). The structure for 3 was confirmed by spectroscopic analysis and total synthesis.

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Trabalho de projeto apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Publicidade e Marketing.

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Partindo da consciência de que o artesanato se encontra num momento de considerável vigor, apesar da aparente supremacia tecnológica, bem como de que a percepção em relação ao artesanato foi sofrendo variações ao longo do tempo, a presente dissertação pretende averiguar o estatuto e o significado do artesanato, no âmbito da prática artística contemporânea. Com o intuito de analisar alguns dos possíveis desdobramentos desta reflexão, o presente estudo divide-se em três capítulos. Após um preâmbulo, que consiste numa breve história dos ofícios com início na Antiguidade Clássica, desembocando na ruptura entre a beleza e a utilidade que surgiu no século XVIII, o primeiro capítulo constitui uma análise das disputas e diálogos entre a arte popular, as belas-artes a indústria, assumindo um balizamento cronológico que se estende desde a Revolução Industrial e do movimento Arts and Crafts de Oitocentos até à era digital que emergiu na década de 1980. O segundo capítulo dedica-se a interrogar o entrelaçamento da actividade artesanal na dicotomia entre a cultura de elite e a cultura de massas, a partir da sua formulação no século XIX e terminando na actualidade. Neste percurso, sobressai a identificação da cultura popular com o feminino e, consequentemente, com a decoração, no contexto do Modernismo, a qual foi alvo de revisão e de crítica no seio do Pós- Modernismo, assim como do feminismo dos anos 1970 e 1980. Procura-se ainda indagar de que maneira o “artesanativismo” feminista inspirou a actual revigoração da aliança entre o artesanato e o activismo. Finalmente, no terceiro e último capítulo, o nosso estudo centra-se na obra de quatro artistas-artesãos contemporâneos, em que os temas anteriormente desenvolvidos são tratados de forma sistemática. Serão problematizadas criações tão díspares e geograficamente distantes quanto as da portuguesa Cristina Rodrigues e do ganiano El Anatsui, da norte-americana Anne Wilson e da austríaca Kathrin Stumreich.

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This research uses the textile/text axis concept as a conceptual tool to investigate the role of textile and text in contemporary women’s art practice and theorizing, investigating textile as a largely hitherto unacknowledged element in women’s art practice of the late 20th and early 21st centuries. Textile and text share a common etymological root, from the Latin textere to weave, textus a fabric. The thesis illuminates the pathways whereby textile and text played an important role in women reclaiming a speaking voice as creators of culture and signification during a revolutionary period of renewal in women’s cultural contribution and positioning. The methodological approach used in the research consisted of a comprehensive literature review, the compilation of an inventory of relevant women artists, developing a classificatory system differentiating types of approaches, concerns and concepts underpinning women’s art practice vis a vis the textile/text axis and a series of three in-depth case studies of artists Tracey Emin, Louise Bourgeois and Faith Ringgold. The thesis points to the fact that contemporary women artists and theorists have rounded their art practice and aesthetic discourse in textile as prime visual metaphor and signifier, turning towards the ancient language of textile not merely to reclaim a speaking voice but to occupy a ground breaking locus of signification and representation in contemporary culture. The textile/text axis facilitated women artists in powerfully countering a culturally inscribed status of Lacanian ‘no-woman’ (a position of abjection, absence and lack in the phallocentric symbolic). Turning towards a language of aeons, textile as fertile wellspring, the thesis identifies the methodologies and strategies whereby women artists have inserted their webs of subjectivities and deepest concerns into the records and discourses of contemporary culture. Presenting an anatomy of the textile/text axis, the thesis identifies nine component elements manifesting in contemporary women’s aesthetic practice and discourse. In this cultural renaissance, the textile/text axis, the thesis suggests, served as a complex lexicon, a system of labyrinthine references and signification, a site of layered meanings and ambiguities, a body proxy and a corporeal cartography, facilitating a revolution in women’s aesthetic praxis.

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L’ús d’embarcacions d’esbarjo és una activitat molt extesa a la zona costanera del Garraf. Aquesta activitat origina fluxos energètics i materials els quals, a la vegada, són els productors d’impactes sobre el medi natural i l’entorn portuari. En aquest article es realitza una avaluació d’aquests fluxos (energia, aigua i residus) al Port Esportiu d’Aiguadolç mitjançant indicadors escollits especialment per aquesta finalitat, els quals s’han utilitzat posteriorment per analitzar els impactes que es produeixen al port. D’aquesta manera, a partir dels resultats obtinguts s’han exposat diverses propostes de millora amb l’objectiu de disminuir els impactes generats de l’ús i gaudiment dels iots, emfatitzant especialment en els impactes generats quan aquests es troben amarrats al port. Tenint en compte que no existeixen estudis previs publicats sobre aquesta temàtica, aquest article deixa la porta oberta a l’hora de continuar estudiant la incidència sobre el medi que te l’ús d’embarcacions.