S?ntese e reatividade de bases de Schiff como precursoras de ur?ias e tiour?ias assim?tricas potencialmente fungicidas

• Author(s): Souza, Andressa Esteves de
• Date: 2020
• Origin: Oasisbr
• Subject(s): Qu?mica; Qu?mica
• Document Type: Master thesis
• Language: Portuguese

Description

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Made available in DSpace on 2020-11-25T15:13:27Z (GMT). No. of bitstreams: 1 1999 - Andressa Esteves de Souza.pdf: 8173068 bytes, checksum: 4c3c31a54f32f2b7955c74fc414327b9 (MD5) Previous issue date: 1999-11-09

Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES

As part of the synthetic program, in this work it was prepare two new systems N-3,3-diphenylpropryl-N-[p-X-benzyl]-N' -phenylureas (I) and thioureas The synthesis of the target compounds were realized by the reaction of the secondary amines, obtained from reduction of Schiff bases, and phenylisocianide and isothiocianide. New methodologies, as the use of solid suportt and microwave irradiation, were investigated in the synthesis of Schiff bases as intermediates. The theoretical study involving molecular modeling was performed to Schiff bases with the purpose of comparing the experimental and theoretical reactivity results reduction reaction on amine preparation. All final and intermediate products were characterized by IV, 1H and 13C NMR Spectroscopy. The 2D-NMR experiments, such as 1Hx1H-cosy, were utilized to aromatic hydrogen elucidation. Furthemore, based in literature reports, it was investigated the anti-fungai activity of ureas and thioureas. The assays were realized with Fusarium and had showed that the substituted urea derivatives with withdrawing groups were potentially active.

Como parte do programa de s?ntese de duas novas s?ries de ur?ias e tiour?ias, este trabalho relata a obten??o dos sistemas N-[3,3-difenil]-N-[p-Xbenzil]- N'-fenilur?ias (1) e tiour?ias (II). A s?ntese destas subst?ncias envolveu a rea??o entre aminas secund?rias, derivadas de bases de Schiff, e isocianatos e isotiocianato de fenila. Na obten??o de uma das s?ries de bases de Schiff utilizadas como intermedi?rio, foi investigada a viabilidade da prepara??o das mesmas em meio de suporte s?lido e irradia??o de microondas. Um estudo te?rico de modelagem molecular foi realizado a fim se tentar corroborar com os resultados experimentais obtidos n a prepara??o das aminas secund?rias, precursoras das ur?ias e tiour?ias. A elucida??o estrutural dos produtos e intermedi?rios foi realizada por espectroscopia de N e de RMN de 1H e de 13C. A t?cnica de correla??o homonuclear 1H x 1H-cosy foi utilizada para auxiliar na elucida??o dos sinais da regi?o dos arom?ticos. A partir de dados encontrados na literatura, neste trabalho investigamos a atividade fungicida das ur?ias e tiour?ias preparadas. Os experimentos foram realizados com o fungo Fusarium em um per?odo de 7 dias e mostraram que as ur?ias substitu?das com grupos retiradores de el?trons s?o potencialmente ativas.