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Previous issue date: 2015-09-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As ftalidas ou isobenzofuranonas são γ -lactonas fundidas com um anel aromático. As isobenzofuran-1(3H)-onas, e seus análogos correspondentes tetraidro- e hexaidroisobenzofuran-1(3H)-onas, são produtos naturais e possuem variadas atividades biológicas, como: inseticida, herbicida, anti- inflamatória e antifúngica. O presente trabalho teve por objetivo sintetizar novas ftalidas visando avaliar a atividade inseticida e herbicida desses compostos. A rota sintética escolhida teve como material de partida a lactona furan-2(5H)-ona (1). Essa substância foi então submetida à reação de Diels-Alder com o ciclopentadieno, levando a formação dos compostos (3aR,4S,7R,7aS)- e (3aS,4R,7S,7aR)-3a,4,7,7a-tetraidro-4,7-metanoisobenzofuran-1(3H)-ona (2) e (3aS,4S,7R,7aR)- e (3aR,4R,7S,7aS)-3a,4,7,7a-tetraidro-4,7- metanoisobenzofuran-1(3H)-ona (3) com 66,3% e 17,7% de rendimento, respectivamente. Esses compostos foram submetidos às reações de epoxidação, hidrogenação, cloração e bromação, e foram obtidas onze substâncias com rendimentos que variaram de 59 a 98%. Com o epóxido obtido a partir do composto 2 foi realizada à reação de abertura de epóxido em meio ácido, variando-se o álcool empregado, o que deu origem a cinco substâncias em rendimentos que variaram de 46 a 74%. Os compostos sintetizados foram completamente caracterizados, utilizando-se espectroscopia no IV, espectroscopia de RMN de 1 H e de a 13 C, NOEDIFF, técnicas bidimensionais HMBC, HSQC, HETCOR e NOESY, espectrometria de massas, além de em alguns casos cálculos computacionais. As ftalidas sintetizadas tiveram sua atividade inseticida investigada por meio da realização de bioensaios com a lagarta Diaphania hyalinata. Dentre as substâncias avaliadas, os compostos 11a+11b, 11b e 9a+9b foram os mais ativos. Considerando-se a dose de 45,2 mol de substância/g de inseto e um período de 48 horas, estas substâncias causaram, respectivamente, 84,8, 91,3 e 96,3% de mortalidade dos insetos. Esses resultados são melhores que o encontrado para o inseticida padrão utilizado (piperina) que apresentou uma mortalidade de 64,5%. Foi verificada também a seletividade desses inseticidas em favor de organismos não-alvos: a abelha polinizadora e produtora de mel (Tetragonisca angustula) e o inimigo natural (Solenopsis saevissima). Os resultados obtidos mostram que as substâncias 11b e 11a+11b foram seletivas, uma vez que a mortalidade dos organismos benéficos foi inferior à obtida para a praga D. hyalinata. Foi realizada também uma avaliação in vitro do efeito fitotóxico dos compostos sintetizados sobre o crescimento radicular e da parte aérea de plâtulas de pepino (Cucumis sativus), sorgo (Sorghum bicolor), cebola (Allium cepa) e picão preto (Bidens pilosa). Os resultados mostraram que alguns desses compostos são capazes de influenciar significativamente o crescimento dessas plântulas. As lactonas 8, 9a+9b, 11a+11b, 11a, 11b e 18 foram as mais ativas frente a todas as espécies testadas. Esses resultados revelam que as isobenzofuran-1(3H)-onas representam uma boa plataforma estrutural para a descoberta de novos compostos com propriedades fitotóxicas e inseticidas. / Phthalides, also known as isobenzofuranones, are characterized by a bicyclic nucleus derived from the fusion of a γ -lactone with a benzene. Isobenzofuran- 1(3H)-ones, and their corresponding analogs tetrahydro- and hexahydroisobenzofuran-1(3H)-ones are frequently found in naturally occurring substances, and exhibit a broad spectrum of biological activities, such as insecticide, herbicide, antiinflammatory and antifungal agents. This study aimed to synthesize new phthalides to evaluate the insecticidal and herbicide activity such compounds. The synthetic route chosen had the furan-2(5H)-one (1) as the starting material. This substance was then subjected to the Diels-Alder reaction with cyclopentadiene, leading to the formation of compounds (3aR,4S,7R,7aS)- and (3aS,4R,7S,7aR)-3a,4,7,7a-tetrahydro-4,7- methanoisobenzofuran-1(3H)-one (3aR,4R,7S,7aS)-3a,4,7,7a- (2) and (3aS,4S,7R,7aR)- and tetrahydro-4,7-methanoisobenzofuran-1(3H)-one (3) in 66.3% and 17.7 % yield, respectively. These compounds were subjected to epoxidation, hydrogenation, chlorination and bromination reactions and eleven substances were obtained with yields ranging from 59 to 98%. With the epoxide obtained from compound 2 was performed to epoxide opening reaction in the presence of acid, by varying the alcohol employed, which led to the formation of five substances in yields ranging from 46 to 74%. All the compounds prepared were fully characterized by IR spectroscopy, 1 H and 13 C NMR spectroscopy, NOEDIFF, two-dimensional techniques HMBC, HSQC, HETCOR and NOESY, mass spectrometry, and in some cases theorical computation. The synthesized phthalides had their insecticidal activity investigated by performing bioassays with caterpillar Diaphania hyalinata. Among the evaluated substances 11a+11b, 11b and 9a+9b were the most active. Considering the dose of 45.2 mol substance/g of insect and a period of 48 hours, these substances caused 84.8, 91.3 and 96.3% of mortality of insects, respectively. These compounds were more active than the commercial piperine which has presented 64.5% of mortality. It was also verified the selectivity of these insecticides in favor of non-target organisms: a bee pollinating and producing honey (Tetragonisca angustula) and the natural enemy (Solenopsis saevissima). The results showed that the substances 11b and 11a+11b were selective, since the mortality of beneficial organisms was less than that obtained for the pest D. hyalinata. On another bioassay the compounds were evaluated for their capacity to inhibit the radicle and the aerial part growth of Cucumis sativus, Sorghum bicolor, Allium cepa, and Bidens pilosa seedlings. The results showed that some of these compounds are capable of influencing significantly the growth of these seedlings. Lactones 8, 9a+9b, 11a+11b, 11a, 11b, and 18 were the most active against all species tested. These results show that isobenzofuran-1(3H)-ones represent good structural platform for the discovery of new compounds displaying selective insecticide and phytotoxic properties.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:123456789/8498 |
| Date | 04 September 2015 |
| Creators | Teixeira, Milena Galdino |
| Contributors | Demuner, Antônio Jacinto, Teixeira, Róbson Ricardo, Alvarenga, Elson Santiago de |
| Publisher | Universidade Federal de Viçosa |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFV, instname:Universidade Federal de Viçosa, instacron:UFV |
| Rights | info:eu-repo/semantics/openAccess |
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