Otimização de rota sintética para a obtenção de compostos diidrobenzofurânicos bioativo
Carregando...
Tipo
TCC
Data de publicação
2018-12
Periódico
Citações (Scopus)
Autores
Fernandes, Gustavo Ariel Borges
Orientador
Sonehara, Ieda Yuriko
Título da Revista
ISSN da Revista
Título de Volume
Membros da banca
Programa
Resumo
O anel benzofurano é um importante synthon para a síntese de novos compostos bioativos, além de estar presente em compostos que apresentam efeitos em doenças do sistema nervoso central. As reações envolvidas na obtenção deste grupo são muito importantes e devem ser alvos de otimização para baratear seus custos. Alilação é uma reação de substituição nucleofílica que ocorre entre fenóis para-substituídos e brometo de alila, resultando em alil-fenil éters. O rearranjo de Claisen é uma reação de isomerização realizada através de altas temperaturas, e que consiste no deslocamento do grupo alila para a posição orto do anel. Este trabalho tem como objetivo, analisar sistematicamente os efeitos que regem as reações e otimizar o processo de obtenção barateando-o e o tornando mais “verde”. As metodologias empregadas para a alilação foram a convencional e a assistida por ultrassom, enquanto que a metodologia empregada no rearranjo de Claisen utilizou aquecimento por microondas. Os resultados indicaram que a metodologia convencional gerou melhores rendimentos que a metodologia ultrassônica na alilação dos fenóis, e provavelmente não ocorre por efeito sonoquímico. Também observa-se uma forte influência dos substituintes na velocidade dessa reação. Para o rearranjo de Claisen, o DMF ainda foi o melhor solvente, e a proporção de diglima e água 1:1 a 200 °C forneceu maiores taxas de conversão. O estudo fatorial mostrou que a temperatura tem efeito mais significativo que o solvente e que não apresentam efeito de interação significativo.
The benzofuran ring is an important synthon for new synthetic compounds, besides being present in compounds that have effects in diseases affecting the central nervous system. The reactions involved in the synthetic process are very important and must be optimized concerning cost and the chance for a greener reaction. Allylation is a substitution reaction that occurs between para-substituted phenols and allyl bromide, resulting in allyl-phenyl ethers. Claisen rearrangement is an isomerization reaction that occurs through high temperatures, consisting in allyl group displacement to the orto position of the ring. The objective of the present research is to systematically analyze the effects that command these reactions, optimizing the process towards one that’s less expensive and greener. The methodologies used for the allylation were the conventional and the ultrasound-assisted ones, while the methodology used in Claisen rearrangement was heating through microwave. The results demonstrated that the conventional methodology presented better yields than the ultrasonic one in the allylation, and that it is probably not occurring by sonochemistry effect. It was observed a strong inlfuence of the substituent effect on the reaction rate. For the Claisen rearrangement the DMF is still the best solvent and the the 1:1 proportion diglime:water in 200 °C provided the best conversion rate. Statistics showed that temperature has a more significant effect than solvent, and their interaction has not shown significant effects.
The benzofuran ring is an important synthon for new synthetic compounds, besides being present in compounds that have effects in diseases affecting the central nervous system. The reactions involved in the synthetic process are very important and must be optimized concerning cost and the chance for a greener reaction. Allylation is a substitution reaction that occurs between para-substituted phenols and allyl bromide, resulting in allyl-phenyl ethers. Claisen rearrangement is an isomerization reaction that occurs through high temperatures, consisting in allyl group displacement to the orto position of the ring. The objective of the present research is to systematically analyze the effects that command these reactions, optimizing the process towards one that’s less expensive and greener. The methodologies used for the allylation were the conventional and the ultrasound-assisted ones, while the methodology used in Claisen rearrangement was heating through microwave. The results demonstrated that the conventional methodology presented better yields than the ultrasonic one in the allylation, and that it is probably not occurring by sonochemistry effect. It was observed a strong inlfuence of the substituent effect on the reaction rate. For the Claisen rearrangement the DMF is still the best solvent and the the 1:1 proportion diglime:water in 200 °C provided the best conversion rate. Statistics showed that temperature has a more significant effect than solvent, and their interaction has not shown significant effects.
Descrição
Palavras-chave
síntese , otimização , química verde , alilação , rearranjo de Claisen , synthesis , optimization , green chemistry , allylation , claisen rearrangement