Síntese e avaliação das propriedades luminescentes de β-(hidroxiaril)butenolidas
Carregando...
Data
2022-03-31
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A unidade β-arilbutenolida está presente em vários produtos naturais e sintéticos que apresentam importantes propriedades biológicas como antitumoral, antiviral e antimicrobiana. Entretanto, apesar de suas propriedades biológicas, são raros os procedimentos na literatura onde existe um ou mais grupos hidroxilas ligados ao anel aromático dando origem a β-(hidroxiaril)butenolidas. Portanto, neste trabalho descrevemos a síntese de derivados β-(hidroxiaril)butenolidas a partir da reação entre o ácido tetrônico e fenol na presença de BF3.OMe2. Através dessa reação foram sintetizados três derivados, com rendimentos variando de 85-95%, contendo grupos doadores de elétrons no anel aromático. As vantagens da metodologia descrita são a obtenção dos derivados de interesse em uma única etapa e o uso de materiais comerciais e de menor custo em relação a procedimentos descritos na literatura que geralmente utilizam catalizadores de paládio e ácidos fenilborônicos nem sempre comerciais. Os compostos obtidos apresentam estruturas rígidas e longos sistemas de elétrons π, que aliados à presença do grupo hidroxila no anel aromático podem contribuir para que eles apresentem interessantes propriedades ópticas. Portanto, com base nessas características foram realizados estudos de absorção e fluorescência dos derivados obtidos em diferentes solventes e pH. Os resultados mostraram que as β-(hidroxiaril)butenolidas 3a-c apresentam bandas de emissão em 385-422 nm e altos rendimentos quânticos em diferentes solventes. Na água ocorre supressão da fluorescência, assim como em soluções mais concentradas de ácido acético. As propriedades luminescentes dos derivados, embora preliminares, indicam potencial uso como sensor químico para determinação de água em solvente orgânico.
The β-arylbutenolide unit is present in several natural and synthetic products that have important biological properties such as antitumor, antiviral and antimicrobial. However, despite its biological properties, there are few procedures in the literature where there is one or more hydroxyl groups attached to the aromatic ring, giving rise to β-(hydroxyaryl)butenolides. Therefore, in this work we describe the synthesis of β-(hydroxyaryl)butenolide derivatives from the reaction between tetronic acid and phenol in the presence of BF3.OMe2. Through this reaction, three derivatives were synthesized, with yields varying from 85-95%, containing electron-donating groups in the aromatic ring. The advantages of the methodology described are obtaining the derivatives of interest in a single step and the use of lower cost commercial materials compared to procedures described in the literature that generally use palladium catalysts and phenylboronic acids that are not always commercial. The compounds obtained have rigid structures and long systems of π electrons, which together with the presence of the hydroxyl group on the aromatic ring can contribute to their having interesting optical properties. Therefore, based on these characteristics, absorption and fluorescence studies of the derivatives obtained in different solvents and pH were carried out. The results showed that β-(hydroxyaryl)butenolides 3a-c present emission bands at 385-422 nm and high quantum yields in different solvents. Fluorescence suppression occurs in water, as well as in more concentrated solutions of acetic acid. The luminescent properties of the derivatives, although preliminary, indicate potential use as a chemical sensor for the determination of water in organic solvent.
The β-arylbutenolide unit is present in several natural and synthetic products that have important biological properties such as antitumor, antiviral and antimicrobial. However, despite its biological properties, there are few procedures in the literature where there is one or more hydroxyl groups attached to the aromatic ring, giving rise to β-(hydroxyaryl)butenolides. Therefore, in this work we describe the synthesis of β-(hydroxyaryl)butenolide derivatives from the reaction between tetronic acid and phenol in the presence of BF3.OMe2. Through this reaction, three derivatives were synthesized, with yields varying from 85-95%, containing electron-donating groups in the aromatic ring. The advantages of the methodology described are obtaining the derivatives of interest in a single step and the use of lower cost commercial materials compared to procedures described in the literature that generally use palladium catalysts and phenylboronic acids that are not always commercial. The compounds obtained have rigid structures and long systems of π electrons, which together with the presence of the hydroxyl group on the aromatic ring can contribute to their having interesting optical properties. Therefore, based on these characteristics, absorption and fluorescence studies of the derivatives obtained in different solvents and pH were carried out. The results showed that β-(hydroxyaryl)butenolides 3a-c present emission bands at 385-422 nm and high quantum yields in different solvents. Fluorescence suppression occurs in water, as well as in more concentrated solutions of acetic acid. The luminescent properties of the derivatives, although preliminary, indicate potential use as a chemical sensor for the determination of water in organic solvent.
Descrição
Palavras-chave
Ácido tetrônico, Butenolidas, Fluorescência, Solvatocromismo, Tetronic acid, Butenolides, Fluorescence, Solvatochromism