Síntese e atividade antifúngica do avenaciolídeo e de bis-y-lactonas análogas com cadeias laterais alifáticas

• Autor(a) principal: Lage, Tiago Coelho de Assis
• 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/123456789/2113
• topic: Bis-y-lactonas; Fungicidas; Avenaciolídeo; Bis-y-lactones; Fungicides; Avenaciolide; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA

Avenaciolide is a natural product with an α,β-unsaturated bis-γ-lactone structure and a linear lateral chain with eight carbon atoms. Using the Chiral pool strategy, two avenaciolide analogs were prepared from D-glucose, containing linear lateral chains of 11 and 17 carbon atoms, [A] and [B], respectively. The different lateral chains were added via Wittig reactions of the appropriated ylides and 3-desoxy-3-C-(carbomethoxymethyl)-1,2-O-isopropylidene-α-D-ribofuranose. The bis-γ-lactone skeleton was obtained after catalytic hydrogenation of the Wittig products followed by acid hydrolysis and Jones oxidation. The exocyclic double bond was added to the bis-γ-lactones by decarboxylative methylenation reactions. The antifungal activities of avenaciolide and the new analogs were tested in vitro against Colletotrichum gloesporioides, Aspergillus flavus and Fusarium solani, using the disc diffusion method. The bis-γ-lactones activities against A. flavus were further investigated by the Poisoned Food method. Avenaciolide was more active than their synthetic analogs, [A] being more active than [B], with respect to the three fungi tested. The IC50 of avenaciolide, [A] and [B] values against A. flavus were 0.11, 0.24 and 1.93 mmol.L-1, respectively. These results indicated that the increase of the lateral chain length with respect to avenaciolide reduces the antifungal activity of the bis-γ-lactones. Avenaciolide shows good agrochemical potential for the control of F. solani, A. flavus and C. gloeosporioides (ascending order of activity).