Publicação
Synthesis of β-benzo[b]thienyldehydrophenylalanine derivatives by one-pot palladium-catalyzed borylation and suzuki coupling (BSC) and metal-assisted intramolecular cyclization: studies of fluorescence and antimicrobial activity
| Resumo: | Palladium-catalyzed borylation and Suzuki coupling (BSC) in a one-pot procedure was successfully applied to the synthesis of several β-substituted dehydrophenylalanines in the benzo[b]thiophene series, with the stereochemistry of the starting materials being maintained. Bromobenzo[b]thiophenes bearing an ortho EDG (OMe or Me) were used as the components to be borylated with pinacolborane, whilst pure stereoisomers of β-bromodehydrophenylalanines were used as the other Suzuki coupling components. Treatment of the obtained methyl ester of (Z)-N-(tert-butoxycarbonyl)-β- (2,3,5-trimethylbenzo[b]thien-6-yl)dehydrophenylalanine with Pd(OAc)2 and Cu(OAc)2 in DMF at 160 °C gave two in dole derivatives (1:3), the major product resulting from isomerization and cyclization and the minor product resulting from direct cyclization (thienoindole). Carrying out the reaction at 100 °C gave the same products in similar amounts. Use of the methyl ester of (Z)-N-(tert-butoxycarbonyl)-β- (2,3,7-trimethylbenzo[b]thien-6-yl)dehydrophenylalanine as starting material gave only one product, resulting from isomerization and cyclization at 100 °C. Two of the cyclized compounds were subjected to fluorescence studies; the thienoindole could be useful as a fluorescent probe. Preliminary studies of antimicrobial activity were performed on the precursors and on the cyclized products. |
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| Autores principais: | Abreu, Ana S. |
| Outros Autores: | Ferreira, Paula M.T.; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.; Calhelha, Ricardo C.; Estevinho, Leticia M. |
| Assunto: | Dehydrophenylalanines Benzothiophenes Borylation Suzuki coupling Cyclization Indoles Fluorescence Antimicrobial activity |
| Ano: | 2005 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Palladium-catalyzed borylation and Suzuki coupling (BSC) in a one-pot procedure was successfully applied to the synthesis of several β-substituted dehydrophenylalanines in the benzo[b]thiophene series, with the stereochemistry of the starting materials being maintained. Bromobenzo[b]thiophenes bearing an ortho EDG (OMe or Me) were used as the components to be borylated with pinacolborane, whilst pure stereoisomers of β-bromodehydrophenylalanines were used as the other Suzuki coupling components. Treatment of the obtained methyl ester of (Z)-N-(tert-butoxycarbonyl)-β- (2,3,5-trimethylbenzo[b]thien-6-yl)dehydrophenylalanine with Pd(OAc)2 and Cu(OAc)2 in DMF at 160 °C gave two in dole derivatives (1:3), the major product resulting from isomerization and cyclization and the minor product resulting from direct cyclization (thienoindole). Carrying out the reaction at 100 °C gave the same products in similar amounts. Use of the methyl ester of (Z)-N-(tert-butoxycarbonyl)-β- (2,3,7-trimethylbenzo[b]thien-6-yl)dehydrophenylalanine as starting material gave only one product, resulting from isomerization and cyclization at 100 °C. Two of the cyclized compounds were subjected to fluorescence studies; the thienoindole could be useful as a fluorescent probe. Preliminary studies of antimicrobial activity were performed on the precursors and on the cyclized products. |
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