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Palladium-catalyzed amination and cyclization to heteroannellated indoles and carbazoles IPB - Escola Superior Agrária
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, Gilbert.
New ortho-bromodiarylamines in the benzo[b]thiophene series were prepared by palladium-catalyzed amination, either in the benzene or in the thiophene ring. These were submitted to palladium-catalyzed cyclization, under different required conditions, to give several differently substituted thieno[3,2-c] or [2,3-b]carbazoles and indolo[3,2-b]benzo[b]thiophenes. This constitutes a novel synthetic route to both tetracyclic systems
Tipo: Article Palavras-chave: Palladium; Amination; Ortho-bromodiarylamines; Cyclization.
Ano: 2003 URL: http://hdl.handle.net/10198/817
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Synthesis of diarylamines in the benzo[b]thiophene series bearing electron donating or withdrawing groups by Buchwald–Hartwig C–N coupling IPB - Escola Superior Agrária
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, Gilbert.
Diarylamines in the benzo[b]thiophene series bearing electron donating or withdrawing groups, were prepared by Buchwald– Hartwig C–N coupling in moderate to high yields. The conditions used were Pd(OAc)2 (3 mol%), BINAP as ligand (4 mol%) and Cs2CO3 as base (1.4 equiv.), in toluene at 1008C, being 6-bromo or amino benzo[b]thiophenes coupled, respectively, with substituted anilines or phenylbromides. The 6-aminobenzo[b]thiophene derivatives were also prepared by palladium catalyzed C–N coupling of the corresponding 6-bromo compounds with benzophenone imine, followed by acidic hydrolysis of the imino derivatives. When 4-nitrobromobenzene and 4-bromobenzonitrile were used as coupling components, triarylamines were also isolated in small amounts. The presence...
Tipo: Article Palavras-chave: Buchwald–Hartwig coupling; Palladium; Amination; Diarylamines; Benzo[b]thiophenes.
Ano: 2003 URL: http://hdl.handle.net/10198/818
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Palladium-catalysed amination of electron-deficient or relatively electron-rich benzo[b]thienyl bromides: preliminary studies of antimicrobial activity and SARs IPB - Escola Superior Agrária
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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