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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

Sintese dos fragmentos C1-C5 e C7-C13 da (-)-Ebelactona A / Synthesis of C1-C5 and C7-C13 fragments of (-)-Ebelactone A

Gonçalves, Caroline da Costa Silva 29 July 2005 (has links)
Orientador: Luiz Carlos Dias / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-06T03:43:39Z (GMT). No. of bitstreams: 1 Goncalves_CarolinedaCostaSilva_M.pdf: 2686591 bytes, checksum: c80dce86656a36dd72ca46fac32d08d0 (MD5) Previous issue date: 2005 / Resumo: As ebelactonas A e B são inibidores enzimáticos isoladas pelo grupo de Umezawa em 1980, a partir de uma cepa de cultura de solos actinomicetos (MG7-G1 referente a Streptomyces aburaviensis). Neste trabalho descrevemos a síntese dos fragmentos C1-C5 e C7-C13 da (-)-ebelactona A. Os fragmentos C1-C5 e C7-C13 da (-)-ebelactona A são oriundos de um intermediário comum, o álcool 72. As etapas chave incluem uma reação do tipo aldol anti e uma hidroboração diastereosseletiva. O fragmento C1-C5 foi obtido em 6 etapas a partir da N-propioniloxazolidinona com rendimento global de 32%. Alternativamente, sintetizamos o anel b-lactona, uma segunda versão do fragmento C1-C5, sendo o mesmo obtido em 13 etapas com um rendimento global de 2,8%. O fragmento C7-C13 foi obtido em 14 etapas a partir da N-propioniloxazolidinona com rendimento global de 5,5%. As etapas principais incluem uma reação de Horner-Wadsworth-Emmons, uma epoxidação diastereosseletiva de um álcool alílico com m-CPBA seguida de abertura do epóxido com Me2CuCNLi2. / Abstract: The ebelactones A and B are enzime inhibitors isolated by Umezawa and cowokers in 1980, from a culture strain of soil actinomycetes (MG7-G1 related to Streptomyces aburaviensis). This work describes the synthesis of C1-C5 and C7-C13 fragments of (-)-ebelactone A. The C1-C5 and C7-C13 fragments of (-)-ebelactone A were prepared from a common intermediate, alcohol 72. Notable features of this approach include an anti-aldol reation and a diastereoselective hydroboration. Fragment C1-C5 was prepared in 6 steps and 32% overall yield from N-propionyloxazolidinone. A second version of C1-C5 fragment, corresponding to the b-lactone ring, was prepared in 13 steps and 2.8% overall yield. Fragment C7-C13 was prepared in 14 steps and 5.5% overall yield from N-propionyloxazolidinone. Notable features include a Horner-Wadsworth-Emmons, a diastereoselective epoxidation of an allylic alcohol with m-CPBA followed by epoxide opening with Me2CuLi2. / Mestrado / Quimica Organica / Mestre em Química

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