Síntese e avaliação do efeito sobre o transporte de elétrons da fotossíntese de derivados de isobenzofuran-1(3H)-onas

• Autor(a) principal: Pereira, Jorge Luiz
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2138
• topic: Isobenzofuran-1(3H)-ona; Fitalidas; Isobenzofuranonas; Fotossíntese; Atividade fitotóxica; Transporte de elétrons na fotossíntese; Isobenzofuran-1(3H)-one; Phtalides; Photosynthetic electron transport; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA

Isobenzofuran-1(3H)-ones (phtalides), fused-ring aromatic y-lactones, have attracted the attention of various research groups due to, in part, to their biological activities. Among various bioactive isobenzofuran-1(3H)-ones is the natural phytotoxin 4-methoxy-5-methyl-6-(3-methylbut-2-enyloxy)isobenzofuran-1(3H)-one. This secondary metabolite is capable of inhibiting in vitro the photosynthetic electron transport. The present investigation aimed to synthesize a variety of 4-methoxy-5-methyl-6-(3-methylbut-2-enyloxy)isobenzofuran-1(3H)-one analogues and evaluate their potential as photosynthetic inhibitors. In the synthetic routes used to prepare the analogues were utilized the palladium catalyzed ortho alkylation of benzoic acids, O-alkylation reactions and addition reactions to the double bounds. The structures of synthesized compounds were confirmed based on NMR, IR and MS analyses. The structure of some isobenzofuran-1(3H)-ones were also investigated by X-ray analysis. The biological activity of the synthesized isobenzofuran-1(3H)-ones, as well as by-products and synthetic intermediates, was evaluated in vitro as the ability to interfere with light-driven reduction of ferricyanide by isolated spinach chloroplasts. Among the fourteen evaluated compounds, eight was able to significantly reduce the electron flow from water to K3[Fe(CN)6]. In addition, two compounds were capable of inhibiting the photosynthetic electron transport by 40%. The inhibitory effect presented by one of the compounds namely 5-(2,3-dibromo-3-methylbutoxy) isobenzofuran-1(3H)-one was equipotent to the natural phytotoxin 4-methoxy-5-methyl-6-(3-methylbut-2-enyloxy) isobenzofuran-1(3H)-one.