Synthesis of bis-amino acid derivatives by Suzuki cross-coupling, Michael addition and substitution reactions

• Autor(a) principal: Ferreira, Paula M. T.
• Data de Publicação: 2009
• Outros Autores: Monteiro, Luís S., Queiroz, Maria João R. P., Pereira, G.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/72915
• topic: Dehydroamino acids; Bis-amino acids; Bis-Suzuki coupling; Michael addition; Substitution reaction; Science & Technology

Several bis-amino acids were prepared using a bis-Suzuki coupling (compounds 4-8, 10), a sequential Michael addition and bis-Suzuki coupling (compounds 12, 13) and a Michael addition followed by a substitution reaction (compounds 18, 19). Thus, the pure stereoisomer of the methyl esters of N-(tert-butoxycarbonyl)-beta-bromodehydroaminobutyric acid and dehydrophenylalanine and of N-benzyloxycarbonyl-beta-bromodehydroaminobutyric acid were reacted with 1,4-phenylene-bis-boronic acid or 9,9-dioctyl-9H-fluorene-2,7-bis-boronic acid using modified Suzuki coupling conditions. The corresponding bis-dehydroamino acid derivatives were obtained in good to high yields maintaining the stereochemistry of the starting materials. This reaction was also applied successfully to a brominated dehydrodipeptide and 1,4-phenylene-bis-boronic acid showing that it could be used to create cross-links in peptide chains. An N,N-diacyldehydroalanine derivative was used in a sequential Michael addition and bis-Suzuki coupling giving a p-terphenyl bis-amino acid and a fluorenyl bis-amino acid in good yields. Two bis-alpha,beta-diamino acids were obtained by a Michael addition of 1,2,4-triazole to the methyl esters of N-(4-toluenesulfonyl), N-(tert-butoxycarbonyl) dehydroamino acids followed by treatment with ethylenediamine.