Palladium‐Catalysed Amination of Electron‐Deficient or Relatively Electron‐Rich Benzo[<i>b</i>]thienyl Bromides − Preliminary Studies of Antimicrobial Activity and SARs

Queiroz, Maria João R. P.; Begouin, Agathe; Ferreira, Isabel C.F.R.; Kirsch, Gilbert; Calhelha, Ricardo C.; Barbosa, Sandra; Estevinho, Letí­cia M.

doi:10.1002/ejoc.200400218

Cited by 40 publications

(24 citation statements)

References 22 publications

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“…These coupling conditions are required for the C-N coupling of heteroaromatic amines as already reported by others 12 and verified by us in an earlier work. 13 The methoxylated coupling products 3a and 3c were obtained in good to high yields from bromo compound 1 and methoxylated anilines but when 3-methoxybromobenzene was coupled with amine 2 the yield for 3b was only 40%. Almost the same yield (42%) was observed in the synthesis of 3d from amine 2 and 4-bromobenzonitrile.…”

Section: Synthesismentioning

confidence: 99%

Synthesis and antioxidant activity evaluation of new 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo[b]thiophenes obtained by Buchwald–Hartwig C–N cross-coupling

Queiroz

Ferreira

Calhelha

et al. 2007

Bioorganic & Medicinal Chemistry

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Abstract-New 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo [b]thiophenes were prepared by palladium-catalyzed Buchwald-Hartwig cross-coupling of 7-bromo or 7-amino-2,3-dimethylbenzo[b]thiophenes, previously prepared by us, with substituted (4-methoxy or 3,4-dimethoxy) anilines and 3-aminopyridine or with substituted (3-methoxy or 4-cyano) bromobenzenes and 2-bromopyridine, respectively, using Pd(OAc) 2 , rac-BINAP or Xantphos as ligands, and Cs 2 CO 3 as base. Their antioxidant properties were evaluated by several methods: reducing power, scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, inhibition of erythrocyte hemolysis and inhibition of lipid peroxidation using the b-carotene linoleate system. EC 50 values for all the methods were determined and it was possible to establish some structure-activity relationships (SARs) based on the presence and position of different substituents on the phenyl ring (1 or 2 OMe and C"N), on the presence of a pyridine ring and on the position of its nitrogen atom relative to the N-H bond.

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Section: Synthesismentioning

confidence: 99%

Synthesis and antioxidant activity evaluation of new 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo[b]thiophenes obtained by Buchwald–Hartwig C–N cross-coupling

Queiroz

Ferreira

Calhelha

et al. 2007

Bioorganic & Medicinal Chemistry

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“…32,[68][69][70][71] The strong NaOtBu base, more than the palladium catalyst, limits the tolerance of the process to ancillary functionality. Several approaches have been followed to address functional group compatability.…”

Section: Catalytic Amination Of Functionalized Heteroaryl Chlorides Wmentioning

confidence: 99%

Highly Reactive, General and Long-Lived Catalysts for Palladium-Catalyzed Amination of Heteroaryl and Aryl Chlorides, Bromides, and Iodides: Scope and Structure–Activity Relationships

2008

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We describe a systematic study of the scope and relationship between ligand structure and activity for a highly efficient and selective class of catalysts for the amination of heteroaryl and aryl chlorides, bromides and iodides containing sterically hindered chelating alkylphosphines. In the presence of this catalyst, aryl and heteroaryl chlorides, bromides and iodides react with many primary amines in high yields with part-per-million quantities of palladium precursor and ligand. Many reactions of primary amines with both heteroaryl and aryl chlorides, bromides and iodides occur to completion with 0.0005-0.05 mol % catalysts. A comparison of the reactivity of this catalyst for coupling of primary amines at these loadings is made with catalysts generated from hindered monophosphines and carbenes, and these data illustrate the benefits of chelation. Thus, these complexes constitute a fourth-generation catalyst for the amination of aryl halides, whose activity complements catalysts based on monophosphines and carbenes.

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“…1, 2 We reported some general conditions to obtain diarylamines functionalizing the benzene ring of the benzo [b]thiophene system with arenes bearing electron-donating or -withdrawing groups.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and antimicrobial activity studies of ortho-chlorodiarylamines and heteroaromatic tetracyclic systems in the benzo[b]thiophene series

Queiroz

Ferreira

Gaetano

et al. 2006

Bioorganic & Medicinal Chemistry

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Abstract-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 representative species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus and Bacillus subtilis) and fungi (Candida albicans), were performed. We have also included in the biological assays some pyridine derivatives previously prepared by us, and it was possible to establish some structure-activity relationships (SARs).

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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

Cited by 40 publications

References 22 publications

Synthesis and antioxidant activity evaluation of new 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo[b]thiophenes obtained by Buchwald–Hartwig C–N cross-coupling

Synthesis and antioxidant activity evaluation of new 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo[b]thiophenes obtained by Buchwald–Hartwig C–N cross-coupling

Highly Reactive, General and Long-Lived Catalysts for Palladium-Catalyzed Amination of Heteroaryl and Aryl Chlorides, Bromides, and Iodides: Scope and Structure–Activity Relationships

Synthesis and antimicrobial activity studies of ortho-chlorodiarylamines and heteroaromatic tetracyclic systems in the benzo[b]thiophene series

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