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Antioxidant properties of diarylamines derivatives of benzo[b]thiophenes and amino acids IPB - Escola Superior Agrária
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Barros, Lillian; Abreu, Ana S.; Ferreira, Paula M.T..
Free radical formation is associated with the normal natural metabolism of aerobic cells. The oxygen consumption inherent to cell growth leads to the generation of a series of oxygen free radicals. The interaction of these species with lipid molecules produces new radicals that may interact with biological systems in a cytotoxic manner. Free radicals and their uncontrolled production are responsible for several pathological processes, such as certain tumours (prostate and colon cancers) the reducing properties of diarylamines make them very important as antioxidants, especially as radical scavengers.
Tipo: ConferenceObject
Ano: 2007 URL: http://hdl.handle.net/10198/3720
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Synthesis of pure stereoisomers of benzo[b]thienyl dehydrophenylalanines by Suzuki cross-coupling. Preliminary studies of antimicrobial activity IPB - Escola Superior Agrária
Abreu, Ana S.; Ferreira, Paula M.T.; Monteiro, Luís S.; Ferreira, Isabel C.F.R.; Calhelha, Ricardo C.; Estevinho, Leticia M..
Several benzo[b]thienyldehydrophenylalanines were synthesized from pure stereoisomers of the methyl ester of N-(tertbutoxycarbonyl)- b-bromodehydrophenylalanine as an extension of our previously reported method for the synthesis of dehydrotryptophan analogues to dehydrophenylalanine derivatives. The latter were obtained in high yields by N-deprotection and bromination of N,N-bis-(tertbutoxycarbonyl)-( Z)-dehydrophenylalanine using TFA and NBS. This was carried out in two steps or in a one pot procedure resulting in different E/Z ratios. These compounds were coupled under Suzuki cross-coupling conditions [Pd(PPh3)4, Na2CO3, DME/H2O] with several boronic benzo[b]thienyl acids in good to high yields maintaining the stereochemistry of the starting materials....
Tipo: Article Palavras-chave: Amino acids; Dehydrophenylalanines; Benzo[b]thiophenes; Suzuki coupling; Palladium; Antimicrobial.
Ano: 2004 URL: http://hdl.handle.net/10198/822
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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 IPB - Escola Superior Agrária
Abreu, Ana S.; Ferreira, Paula M.T.; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.; Calhelha, Ricardo C.; Estevinho, Leticia M..
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...
Tipo: Article Palavras-chave: Dehydrophenylalanines; Benzothiophenes; Borylation; Suzuki coupling; Cyclization; Indoles; Fluorescence; Antimicrobial activity.
Ano: 2005 URL: http://hdl.handle.net/10198/823
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