Estudo dos produtos de oxidação do eugenol com ozônio
Data
2021-07-05
Autores
Pereira Junior, Marcos Accioly 
Orientadores
Uemi, Miriam
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Eugenol é um metabólito secundário encontrado em diversas plantas como cravo, canela e manjericão, atuando no mecanismo de defesa contra fungos, bactérias e espécies reativas de oxigênio (ERO). Uma destas ERO é o ozônio (O3), gás formado na troposfera a partir de reações fotocatalíticas entre hidrocarbonetos, óxidos nítricos (NOx) e dióxido de carbono (CO2). Estudos evidenciam o efeito do ozônio em plantações agrícolas, gerando danos e grandes perdas econômicas. Nosso estudo apresenta resultados da reação do eugenol em diferentes solventes, quando expostas a atmosfera de O3. Os produtos da reação foram purificados e analisados por técnicas espectroscópicas de ressonância magnética nuclear (RMN), infravermelho (IV) e massa (EM), que permitiu a identificação dos seguintes compostos: a homovanilina, 4-((1,2,4-trioxolan-3-il)metil)-2-metoxifenol, 4-(2-etoxietil-2-hidroperóxi)-2-metoxifenol, 4-(2-etoxietil-2-hidroperóxi)-2-metoxifenol e 4-(2-hidroperóxi-2-isopropoxietil)-2-metoxifenol, sendo estes três alcóxi-hidroperóxidos ainda não descritos em literatura. O mecanismo de formação destes compostos é baseado no mecanismo de Criegee, que envolve a cicloadição [2+3] do O3 à olefina do eugenol, formando um ozonídeo primário, seguido de quebras de uma ligação C-C e uma ligação O-O, gerando um óxido carbonílico e formaldeído. A estabilização do óxido carbonílico formado pode ocorrer por redução e rearranjo gerando a homovanilina, ou por adição nucleofílica acílica, formando os alcóxi-hidroperóxidos. Estes alcóxi-hidroperóxidos podem ter atividade biológica devido à presença de grupos funcionais como hidroperóxido e fenol, objeto do próximo estudo.
Eugenol is a secondary metabolite found in several plants such as cloves, cinnamon and basil, acting on the defense mechanism against funghi, bacteria and reactive oxygen species (ROS). One of these ROS is ozone (O3), a gas formed in troposphere by photocatalytic reactions between hydrocarbons, nitric oxides (NOx) and carbon dioxide (CO2). Studies show the effect of ozone in agricultural crops, leading to damage to them and high economic losses. Our study reports the results of the reaction of eugenol solutions under O3 atmosphere using different solvents. The reaction products were purified and analyzed by spectroscopy techniques of nuclear magnetic resonance (NMR), infrared (IR) and mass spectrometry (MS), which allowed the identification of the following compounds: homovanillin, 4-((1,2,4-trioxolan-3-yl)methyl)-2-methoxyphenol, 4-(2-hydroperoxy-2-methoxyethyl)-2-methoxyphenol, 4-(2-ethoxy-2-hydroperoxyethyl)-2-methoxyphenol and 4-(2-hydroperoxy-2-isopropoxyethyl)-2-methoxyphenol, and this three last alkoxyhydroperoxides still unpublished. The formation mechanism of these compounds are proposed based on Criegee’s mechanism, which involves the cycloaddition [2+3] of O3 to the olefin of eugenol, forming a primary ozonide, with further cleavage of a C-C bond and an O-O bond, leading to a carbonyl oxide and formaldehyde. The stabilization of the carbonyl oxide formed occurs by either reduction and rearrangement, leading to homovanillin, or by nucleophilic acyl addition, generating the alkoxyhydroperoxides. The alkoxyhydroperoxides may have biological activity due to their functional groups such as hydroperoxide and phenol, being an object of the next study.
Eugenol is a secondary metabolite found in several plants such as cloves, cinnamon and basil, acting on the defense mechanism against funghi, bacteria and reactive oxygen species (ROS). One of these ROS is ozone (O3), a gas formed in troposphere by photocatalytic reactions between hydrocarbons, nitric oxides (NOx) and carbon dioxide (CO2). Studies show the effect of ozone in agricultural crops, leading to damage to them and high economic losses. Our study reports the results of the reaction of eugenol solutions under O3 atmosphere using different solvents. The reaction products were purified and analyzed by spectroscopy techniques of nuclear magnetic resonance (NMR), infrared (IR) and mass spectrometry (MS), which allowed the identification of the following compounds: homovanillin, 4-((1,2,4-trioxolan-3-yl)methyl)-2-methoxyphenol, 4-(2-hydroperoxy-2-methoxyethyl)-2-methoxyphenol, 4-(2-ethoxy-2-hydroperoxyethyl)-2-methoxyphenol and 4-(2-hydroperoxy-2-isopropoxyethyl)-2-methoxyphenol, and this three last alkoxyhydroperoxides still unpublished. The formation mechanism of these compounds are proposed based on Criegee’s mechanism, which involves the cycloaddition [2+3] of O3 to the olefin of eugenol, forming a primary ozonide, with further cleavage of a C-C bond and an O-O bond, leading to a carbonyl oxide and formaldehyde. The stabilization of the carbonyl oxide formed occurs by either reduction and rearrangement, leading to homovanillin, or by nucleophilic acyl addition, generating the alkoxyhydroperoxides. The alkoxyhydroperoxides may have biological activity due to their functional groups such as hydroperoxide and phenol, being an object of the next study.