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Master's Dissertation
DOI
10.11606/D.59.2003.tde-04072007-144124
Document
Author
Full name
Valquiria Aragão
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2003
Supervisor
Committee
Constantino, Mauricio Gomes (President)
Federman Neto, Alberto
Marzorati, Liliana
Title in Portuguese
Sobre a síntese de furanoeliangolidos pela reação de Diels-Alder
Keywords in Portuguese
furanoeliangolidos
síntese produtos naturais
Abstract in Portuguese
Furanoeliangolidos são produtos naturais biologicamente ativos que contêm um esqueleto 11-oxabiciclo[6.2.1]undecano. Neste trabalho nós estudamos duas propostas sintéticas para síntese de um modelo simplificado do furanoeliangolido goiazensolido, através de uma reação de Diels-Alder seguida de clivagem da ligação central dos anéis. No desenvolvimento da primeira proposta nós preparamos o composto mesilato, porém as tentativas de efetuar a reação de eliminação resultaram em mistura complexa ou em produtos indesejados. Na proposta seguinte preparamos o éster, e testamos dois caminhos alternativos, entre várias possibilidades, para dar continuidade à síntese. No primeiro caminho o éster foi hidrolisado ao ácido, mas não foi possível obter a amida de Weinreb correspondente. No segundo caminho, o éster foi reduzido ao álcool, que foi oxidado ao aldeído; quando tratado com o ânion da hidrazona, o aldeído forneceu a hidrazona correspondente ao invés do esperado produto de adição de carbânion. Outras alternativas deverão ser investigadas no futuro.
Title in English
About the synthesis of furanoheliangolides through the Diels-Alder reaction
Keywords in English
furanoheliangolides
synthesis natural products
Abstract in English
Furanoheliangolides are biologically active natural products containing a 11-oxabicyclo[6.2.1]undecane skeleton. In this work we have investigated two different approaches to synthesize a model of the core structure of goyazensolide. Both approaches involve a Diels-Alder reaction and a bond breaking reaction to produce the polycyclic structure. In the first proposal we prepared mesylate compound. Attempts to effect an elimination reaction, however, resulted either in complex mixture or in undesired products. In the second proposal we prepared ester and investigated two alternative paths, out of several possibilities, to proceed the synthesis. In the first, ester was hydrolyzed to acid, but it was not possible to obtain the corresponding Weinreb amide. In the second path the ester was reduced to alcohol, that was oxidized to aldehyde; this, when treated with the anion from hydrazone, furnished hydrazone instead of the expected product of carbanion addition. Further studies should be developed in the future.
 
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ValquiriaMestrado.pdf (1.43 Mbytes)
Publishing Date
2007-07-11
 
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