Síntese de novas benzopironas análogas ao alternariol

• Autor(a) principal: Miranda, Ana Cristina Mendes
• 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/123456789/2117
• topic: Herbicidas; Benzopironas; Alternariol; Herbicides; Benzopyrones; Alternariol; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA

Alternariol, secondary metabolite produced by a fungus of the genus Alternaria, has been found in a variety of plants, this compound contains subunit Benzo[c]chromen-6-ones (biaryl lactones), which occurs in several natural products and are considered great importance for presenting relevant biological activities. Studies indicate that alternariol can be directly related to the high phytotoxicity by these fungi, including on weeds. In this context, this study aimed to synthesize a series of analogous to alternariol, for it was used a synthetic route based on the route described by KOCK 2005, where he held a cross-coupling reaction between halogenated aromatic aldehydes in the ortho position and phenylboronic acid methoxylated in the ortho position, in the presence of a palladium catalyst (Suzuki coupling). The resulting biarilas had the aldehyde grouping oxidized in the presence of sodium chlorite or potassium permanganate generating the respective carboxylic acids. These acids were subjected to a deprotection step of the hydroxyl groups and subsequent formation of a lactonic ring, in the presence of boron tribromide, giving rise to the following analogues alternariol: 2-bromo-7-hydroxy-9-methoxy-6H-benzo[c]chromen-6-one [21a], 2-fluoro-8,9-dimethoxy-6H-benzo[c]chromen-6-one [21b], 3-fluoro-8,9-dihydroxy-6H-benzo[c]chromen-6-one [21e], 2-bromo-6Hbenzo[c]chromen-6-one [21f], 4-bromo-2-methyl-6H-benzo[c]chromen-6-one [21g], 9-fluoro-5H-chromene [4,3-c]pyridin-5-one [21i], 9-chloro-5Hchromene[4,3-c]pyridin-5-one [21j]. The synthesized compounds were characterized using IR spectroscopy, mass spectrometry, NMR spectroscopy 1H and 13C, in addition to two-dimensional NMR technique as HETCOR.