Publicação
Expedient synthesis of amides: application of biomass-derived catalysts and multicompo-nent reactions
| Resumo: | Amides are an extremely important functional group since they are present in several biological structures. In medicinal chemistry, amide is highly attractive for the design of new drugs, whereas a quarter of approved and available drugs in the market have an amide group. Besides drugs, amide bonds are also important functional groups in polymer synthesis, due to their stability and strength. Polyamides are naturally present in composition of diverse biomolecules, such as proteins. Due to this similarity, they have been highly implemented in drug delivery. Traditional methodologies to achieve amides involve combination between a carboxylic acid and an amine, requiring a pre-activation agent of carboxylic acid, lead to waste amounts. The use of catalysts has contributed to the sustainability of amide formation methods. One of the methodologies developed for amide synthesis is the Ritter reaction, which involves reaction of an alcohol with a nitrile catalysed by an acid. Several examples of Ritter reaction reported in literature employed the use of high quantities of strong acids most of them associated to environmental hazards compromise the sustainability of am-ide bond formation. Over the last years, nanocatalysts have been emerging as a green alternative in catalysis, since join the positive aspects of homogeneous and heterogeneous catalysts. In this master thesis, Ritter reaction was performed with several nanocatalysts derived from a natural source, to achieve the corresponding amide. MWCNT provide better yields when compared to other catalysts tested. Additionally, biomass-derived compounds, such as Furfuryl Alcohol (FA), were also employed for this study, however these compounds revealed an undesirable behavior, polymerization of FA. In order to prevent this side reaction, some investigation was performed by employing different additives. Only Na2S2O4 (5%w/w) decreased substantially the polymer formation, but with no influence in amide formation. Next, amide synthesis from several alcohols and nitriles catalyzed by MWCNT was ex-plored, yielding 10 different products ranging from 13% to 78% yields. To produce the polyamides by using biomass building blocks, Ugi reaction was considered. Ap-plying the Ugi reaction to furfural derivatives, an amide was quantitatively obtained, by employing water as solvent, as a potential monomer for further polymerization studies. |
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| Autores principais: | Pereira, Joana Rita Sanches |
| Assunto: | Amides Nanocatalysts Biomass Ritter reaction Ugi reaction |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | Amides are an extremely important functional group since they are present in several biological structures. In medicinal chemistry, amide is highly attractive for the design of new drugs, whereas a quarter of approved and available drugs in the market have an amide group. Besides drugs, amide bonds are also important functional groups in polymer synthesis, due to their stability and strength. Polyamides are naturally present in composition of diverse biomolecules, such as proteins. Due to this similarity, they have been highly implemented in drug delivery. Traditional methodologies to achieve amides involve combination between a carboxylic acid and an amine, requiring a pre-activation agent of carboxylic acid, lead to waste amounts. The use of catalysts has contributed to the sustainability of amide formation methods. One of the methodologies developed for amide synthesis is the Ritter reaction, which involves reaction of an alcohol with a nitrile catalysed by an acid. Several examples of Ritter reaction reported in literature employed the use of high quantities of strong acids most of them associated to environmental hazards compromise the sustainability of am-ide bond formation. Over the last years, nanocatalysts have been emerging as a green alternative in catalysis, since join the positive aspects of homogeneous and heterogeneous catalysts. In this master thesis, Ritter reaction was performed with several nanocatalysts derived from a natural source, to achieve the corresponding amide. MWCNT provide better yields when compared to other catalysts tested. Additionally, biomass-derived compounds, such as Furfuryl Alcohol (FA), were also employed for this study, however these compounds revealed an undesirable behavior, polymerization of FA. In order to prevent this side reaction, some investigation was performed by employing different additives. Only Na2S2O4 (5%w/w) decreased substantially the polymer formation, but with no influence in amide formation. Next, amide synthesis from several alcohols and nitriles catalyzed by MWCNT was ex-plored, yielding 10 different products ranging from 13% to 78% yields. To produce the polyamides by using biomass building blocks, Ugi reaction was considered. Ap-plying the Ugi reaction to furfural derivatives, an amide was quantitatively obtained, by employing water as solvent, as a potential monomer for further polymerization studies. |
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