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Evaluation of the antioxidant properties of diarylamines in the benzo[b]thiophe...
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Vilas-Boas, Miguel; Estevinho, Leticia M.; Begouin, Agathe; Kirsch, GilbertThe 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 arylaminatio...
Synthesis and antimicrobial activity studies of ortho-chlorodiarylamines and he...
Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.; Gaetanoa, Yannick de; Kirsch, Gilbert; Calhelha, Ricardo C.; Estevinho, Leticia M.ortho-Chlorodiarylamines in the 2,3,7-trimethylbenzo[b]thiophene series were prepared in high yields (70–85%) by C–N palladium-catalyzed cross-coupling using P(t-Bu)3 as ligand and NaOt-Bu as base. A palladium-assisted C–C intramolecular cyclization of the coupling products gave thienocarbazoles and the dechlorinated diarylamines. Studies of antimicrobial activity of the compounds obtained, against representati...
Synthesis of the first thieno-δ-carboline. Fluorescence studies in solution and...
Queiroz, Maria João R.P.; Castanheira, Elisabete M.S.; Pinto, Ana M.R.; Ferreira, Isabel C.F.R.; Begouin, Agathe; Kirsch, GilbertThe 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 st...
Palladium-catalysed amination of electron-deficient or relatively electron-rich...
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 react...
Palladium-catalyzed amination and cyclization to heteroannellated indoles and c...
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, GilbertNew 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 tet...
Synthesis of diarylamines in the benzo[b]thiophene series bearing electron dona...
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, GilbertDiarylamines 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-amino...
Tandem palladium-catalyzed borylation and suzuki coupling (BSC) to thienocarbaz...
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, GilbertSubstituted 2-methyl-2'-nitro diaryl compounds in the benzo[b]thiophene series were prepared by palladium-catalyzed, two-step, one-pot borylation/Suzuki coupling (BSC) reaction in good to high yields. The borylation reaction was performed on methylated 6-bromobenzo[b]thiophenes using pinacolborane and was followed by in situ Suzuki coupling with substituted (CF3, OMe) 2-bromonitrobenzenes. The compounds obtaine...
Palladium-catalyzed amination of electron-rich or poor benzo[b]thienyl bromides
Begouin, Agathe; Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, GilbertRecently we have applied the palladium-catalyzed amination to the synthesis of ortho-bromodiarylamincs in the benzo[blthiophene series . Here we describe the application of this methodology to the amination of electron-rich or poor 3-bromobenzo[b}thiophcnes, using the same conditions for both cases.
Novel synthetic routes to thienocarbazoles via palladium or copper catalyzed am...
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, GilbertPalladium or copper catalyzed aminations or amidations were performed to obtain diarylamines and diarylacetamides precursors of thienocarbazoles. The fact that an ortho-bromodiarylamine did not cyclize to the corresponding thienocarbazole under conditions known for carbazoles from ortho-halodiphenylamines, conducted us to a highly efficient method of palladium-catalyzed intramolecular cyclization with N-deprote...
Synthesis of potential anti-tumoral ring a substituted tieno[3,2-c]carbazoles f...
Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Kirsch, GilbertThienocarbazoles bearing electron donating or withdrawing groups in ring a, were prepared by intramolecular oxidative cyclization of diarylamines using stoichiometric or catalytic Pd(OAc)2 amounts, in fair to moderate yields. ln the latter case Cu(OAch was added to reoxidize Pd(O) forrned. The diarylamine precursors were prepared by palladium-catalysed amination.
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