Estudo sobre a síntese de lactonas quinolínicas
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Data
2017-05-09
Autores
Pissurno, Ana Paula da Rocha [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Compostos contendo o núcleo quinolínico apresentam inúmeras propriedades biológicas e estão presentes em muitos fármacos utilizados atualmente contra malária, doenças coronárias e alergias. Existem inúmeras rotas sintéticas para a obtenção de derivados de quinolinas, entretanto, muitas delas são limitadas pelos materiais de partida utilizados e outras não se aplicam, por exemplo, à síntese dos compostos alvos desse trabalho que são lactonas quinolínicas, análogas a lignanas biologicamente ativas. Desta forma, o presente trabalho teve por objetivo propor uma rota sintética mais efetiva para a obtenção de lactonas quinolínicas através do uso de micro-ondas (MO), solventes e reagentes mais adequados reduzindo o tempo de reação e aumentando o rendimento do produto final. Inicialmente foi realizada a síntese dos intermediários anilinolactonas pela reação assistida por micro-ondas entre ácido tetrônico e anilinas. Os produtos foram obtidos após 40 minutos de reação com rendimentos variando de 74 a 98%. Para a obtenção de diferentes lactonas quinolínicas foi realizada a reação entre as várias anilinolactonas e aldeídos aromáticos contendo grupos sacadores e doadores de elétrons. As lactonas quinolínicas foram obtidas com 60 a 97% de rendimento como único produto. Foi testada também a reação para a obtenção de lactonoas dihidroquinolínicas pela reação entre anilinolactonas e aldeídos aromáticos em HCl concentrado. A partir dessa rota foram obtidas as lactonas dihidroquinolínicas como produtos principais em rendimentos variando de 55 a 85%. Nessas condições quando a reação é realizada sob aquecimento por MO ocorre a formação de mistura das lactonas quinolínicas e dihidroquinolínicas em proporções próximas a 1:1. Os produtos obtidos foram isolados e suas estruturas foram confirmadas por RMN de 1H e 13C.
Compounds containing the quinoline nucleus have numerous biological properties and are present in many currently used drugs against malaria, coronary diseases and allergies. There are numerous synthetic routes for obtaining quinolines derivatives, however, many of them are limited by the starting materials used and others do not apply, for example to synthesis of the compounds of this work which are quinolinic lactones, analogous to biologically active lignans. The present work propose a more effective synthetic route to obtain quinolinic lactones through the use of microwaves (MW), solvents and reagents more suitable reducing the reaction time and increasing the yield of the final product. Initially the synthesis of the anilinolactones intermediates was carried out by the microwave-assisted reaction between tetronic acid and anilines. The products were obtained after 40 minutes of reaction with yields ranging from 74 to 98%. To obtain different quinolinic lactones the reaction between various anilinolactones and aromatic aldehydes containing electrondonating or electronwithdrawing substituents. The quinolinic lactones were obtained in 60 to 97% yield as the sole product. The reaction for the preparation of dihydroquinolinic lactones by the reaction between anilinolactones and aromatics aldehydes in concentrated HCl was also tested. From this route, the dihydroquinolinic lactones were obtained, as main products, in yields ranging from 55 to 85%. Under these conditions when the reaction is carried out under heating by WM, the formation of a mixture of the quinolinic and dihydroquinolinic lactones in proportions close to 1:1 occurs. The obtained products were isolated and had their structures confirmed by 1H and 13C NMR.
Compounds containing the quinoline nucleus have numerous biological properties and are present in many currently used drugs against malaria, coronary diseases and allergies. There are numerous synthetic routes for obtaining quinolines derivatives, however, many of them are limited by the starting materials used and others do not apply, for example to synthesis of the compounds of this work which are quinolinic lactones, analogous to biologically active lignans. The present work propose a more effective synthetic route to obtain quinolinic lactones through the use of microwaves (MW), solvents and reagents more suitable reducing the reaction time and increasing the yield of the final product. Initially the synthesis of the anilinolactones intermediates was carried out by the microwave-assisted reaction between tetronic acid and anilines. The products were obtained after 40 minutes of reaction with yields ranging from 74 to 98%. To obtain different quinolinic lactones the reaction between various anilinolactones and aromatic aldehydes containing electrondonating or electronwithdrawing substituents. The quinolinic lactones were obtained in 60 to 97% yield as the sole product. The reaction for the preparation of dihydroquinolinic lactones by the reaction between anilinolactones and aromatics aldehydes in concentrated HCl was also tested. From this route, the dihydroquinolinic lactones were obtained, as main products, in yields ranging from 55 to 85%. Under these conditions when the reaction is carried out under heating by WM, the formation of a mixture of the quinolinic and dihydroquinolinic lactones in proportions close to 1:1 occurs. The obtained products were isolated and had their structures confirmed by 1H and 13C NMR.
Descrição
Palavras-chave
Micro-ondas, Compostos quinolínicos, Compostos dihidroquinolínicos, Anilinolactonas, Lignanas, Microwave, Quinolinic compounds, Dihydroquinolinic compounds, Anilinolactones, Lignans