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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

Síntese de 1,2,4-oxadiazóis 3,5-dissubstituídos derivados de Laminoácidos e arilamidoximas sob irradiação de micro-ondas / Synthesis of 3,5-disubstituted 1,2,4-oxadiazole derivatives from Lamino acids and arylamidoximes under microwave irradiation.

Sauer, André Carpes 28 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Here we report the synthesis and characterization of 3,5-disubstituted 1,2,4-oxadiazole 3 derivatives of N-protected L-amino acid 1 and arilamidoximas 2, and the reaction was performed in a microwave reactor, using water as solvent and DCC (N, N'-dicyclohexylcarbodiimide) as a coupling agent. These compounds were characterized by spectroscopic techniques such as nuclear magnetic resonance of hydrogen (1H NMR) and carbon-13 (13C NMR) and mass spectrometry of low resolution, whereby it was confirmed to obtain the heterocyclic compounds of interest. Studies were conducted of some reaction conditions such as time, temperature and solvents, targeting a comprehensive optimization for this synthetic route. It was also possible to compare the use of microwave irradiation with the conventional method. Through the proposed method, 25 compounds were obtained with yields ranging between 53 to 92%, where the same are considered satisfactory, since the reactions were performed in short reaction times and the green aspect is therefore considered environmentally correct. / Neste trabalho é apresentado a síntese e a caracterização dos 1,2,4- oxadiazóis 3,5-dissubstituídos 3 derivados dos L-aminoácidos N-protegidos 1 e arilamidoximas 2, sendo que a reação foi realizada em reator de micro-ondas, utilizando água como solvente e DCC (N,N -Diciclohexilcarbodiimida) como agente de acoplamento. Estes compostos foram caracterizados por técnicas espectroscópicas de ressonância magnética nuclear de hidrogênio (RMN1H) e carbono-13 (RMN13C) e espectrometria de massas de baixa resolução, através das quais confirmou-se a obtenção dos compostos heterocíclicos de interesse. Foram realizados estudos de algumas condições reacionais, tais como tempo, temperatura e solventes, visando uma otimização abrangente para esta rota sintética. Também foi possível a análise comparativa entre a utilização da irradiação de micro-ondas frente ao método convencional. Através da metodologia proposta, foram obtidos 25 compostos, com rendimentos que variaram entre 53 a 92%, sendo os mesmos considerados satisfatórios, uma vez que as reações foram realizadas em curtos tempos reacionais e com a síntese de caráter verde , sendo portanto considerada ambientalmente correta.

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