Síntese do avenaciolídeo e novos análogos aromáticos e sua atividade frente a fungos fitopatogênicos

• Autor(a) principal: Liberto, Natália Aparecida
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2091
• topic: Avenaciolídeo; Fungicidas; Bis-gama-lactonas; Avenaciolide; Fungicides; Bis-gama-lactone; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA

Avenaciolide, (1R,5R,6R)-4-methylidene-6-octil-2,7- dioxabicyclo[3.3.0]-octan-3,8-dione, is a natural bis-γ-lactone isolated from cultures of A. avenaceus and possess antifungal activity. This dissertation describes the synthesis of avenaciolide and new synthetic analogues (1R,5R,6R)-6-(2- arylethyl)-4-methylidene-2,7- dioxabicyclo[3.3.0]octan-3,8-diones, with the aryl groups: 2-methylphenyl and 3-methylphenyl. D-glucose was used as starting material. Twenty-seven compounds were prepared and 14 of them are unpublished. The new compounds were characterized by infrared and nuclear magnetic resonance spectroscopies, elemental analysis and mass spectrometry. The compounds synthesized and the analogue with group 4- methylphenyl had their antifungal activity tested against Aspergillus flavus, Colletotrichum gloeosporioides and Fusarium solani. Biological assays were performed using the disk diffusion and Poisoned food methods. All compounds were active against these fungi, and the avenaciolide was the most active. The aromatic analogue with methyl substituent in the orto position showed greater inhibition than that with the substituent in meta, which was more active than the compound with the substituent in para position. These results were observed for the three fungi tested indicating that the side chain attached to C6 of bis-γ-lactone has an important role in the antifungal activity, modulating the intensity of the activity. The compounds were more active against C. gloeosporioides and less against F. solani, showing intermediate activity against A. flavus. It was concluded, therefore, that the side chain interferes in the activity of these bis-γ-lactones and that the avenaciolide has potential as agrochemical.