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| Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Vilas-Boas, Miguel; Estevinho, Leticia M.; Begouin, Agathe; Kirsch, Gilbert. |
| The antioxidant properties of substituted diarylamines in the benzo[b]thiophene series were evaluated by their reducing power and free radical scavenging activity. The results were compared with those of standards: acid ascorbic for the first method and BHA and BHT for the second. For both methods it was possible to establish some structure–activity relationships (SARs) based on the position of the arylamination on the benzo[b]thiophene moiety, the presence of different substituents on the phenyl ring (F, 1 or 2 OMe) and on the thiophene ring (H, CO2Et, CO2H). |
| Tipo: Article |
Palavras-chave: Diarylamines; Benzothiophenes; Antioxidant activity; Structure–activity relationships. |
| Ano: 2006 |
URL: http://hdl.handle.net/10198/825 |
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| Queiroz, Maria João R.P.; Begouin, Agathe; Ferreira, Isabel C.F.R.; Kirsch, Gilbert; Calhelha, Ricardo C.; Barbosa, Sandra; Estevinho, Leticia M.. |
| Several diarylamines in the benzo[b]thiophene series were prepared in good to high yields by palladium-catalysed amination of ethyl 3-bromobenzo[b]thiophene-2-carboxylate with anilines and 5-aminoindole in the presence of Pd(OAc)2, BINAP and Cs2CO3 in toluene. The presence of the ester group at the 2-position of the benzo[b]thiophene moiety increases the yields and lowers the heating times relative to the reactions performed with 3-bromobenzo[b]thiophene. When aminopyridines were used instead of anilines, the ligand and the solvent need to be changed to XANTHPHOS and dioxane in the amination reaction. With 2-aminopyridine a onepot C−N coupling and intramolecular cyclization involving the nitrogen atom of the pyridine ring occurred, with loss of ethanol,... |
| Tipo: Article |
Palavras-chave: Amination; Antimicrobial activity; Benzothiophenes; Diarylamines; Fluorescence; Palladium. |
| Ano: 2004 |
URL: http://hdl.handle.net/10198/820 |
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| Queiroz, Maria João R.P.; Castanheira, Elisabete M.S.; Pinto, Ana M.R.; Ferreira, Isabel C.F.R.; Begouin, Agathe; Kirsch, Gilbert. |
| The first thieno-δ-carboline (6,8,9-trimethyl-5H-pyrido[3,2-b]thieno[3,2-f]indole) was prepared in good yield (70%) by intramolecular palladium-assisted cyclization of an ortho-chlorodiarylamine. The latter was in turn selectively synthesized in high yield (90%) by C–N palladiumcatalyzed cross-coupling of 3-bromo-2-chloropyridine with, the also prepared, 6-amino-2,3,7-trimethylbenzo[b]thiophene. Fluorescence studies in solution show that thieno-δ-carboline has a solvatochromic behaviour. Despite the low fluorescence quantum yields in solution, studies of its incorporation in lipid vesicles of DPPC, DOPE and DODAB indicate that thienocarboline is located mainly inside the lipid bilayer, exhibiting different behaviours in gel or liquid-crystalline phases.... |
| Tipo: Article |
Palavras-chave: Palladium-assisted reactions; Thieno-δ-carboline; Fluorescence; Solvatochromic probes; Lipid vesicles. |
| Ano: 2006 |
URL: http://hdl.handle.net/10198/828 |
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