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https://hdl.handle.net/1822/72937
Título: | Synthesis using Suzuki cross couplings of sulfur analogues of dehydrotryptophan with a definite stereochemistry |
Autor(es): | Silva, Natália O. Abreu, Ana S. Ferreira, Paula M. T. Monteiro, Luís S. Queiroz, Maria João R. P. |
Palavras-chave: | Amino acids Sulfur heterocycles Suzuki coupling Stereoisomerism |
Data: | Ago-2002 |
Editora: | Wiley |
Revista: | European Journal of Organic Chemistry |
Resumo(s): | Sulfur analogues of dehydrotryptophan (5-7) were prepared in moderate to good yields (40-80%) by Suzuki cross coupling [Pd(PPh3)(4), Na2CO3 or NaHCO3, DME/H2O, 90 degreesC] of several benzo[b]thiophene boronic acids with the methyl esters of N-tert-butyloxycarbonyl-beta-bromodehydroalanine [Boc-DeltaAla(beta-Br)-OMe] or N-tert-butyloxycarbonyl-beta-bromodehydroaminobutyric acid [Boc-DeltaAbu(beta-Br)-OMe]. The beta-bromodehydroaminoacid precursors 2 were, in turn, synthesized in high yields from the corresponding N,N-diacyldehydroamino acids 1 by treatment with trifluoroacetic acid (TFA) and N-bromosuccinimide (NBS) in two steps or in a one-pot procedure. Both procedures were stereoselective for the E-isomer of Boc-DeltaAla(beta-Br)-OMe. However, for Boc-DeltaAbu(beta-Br)-OMe, different ratios of E/Z isomers were obtained in each procedure. The stereoselectivity for the Z-isomer was increased greatly with the one-pot procedure. Pure isomers were used in the coupling reactions and the stereochemistry of the starting material was generally maintained. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/72937 |
DOI: | 10.1002/1099-0690(200208)2002:15<2524::AID-EJOC2524>3.0.CO;2-W |
ISSN: | 1434-193X |
e-ISSN: | 1099-0690 |
Versão da editora: | https://chemistry-europe.onlinelibrary.wiley.com/journal/10990690 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | CDQuim - Artigos (Papers) |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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2002-Eur. J. Org. Chem. 2524.pdf | 118,06 kB | Adobe PDF | Ver/Abrir |