An efficient one-pot synthesis of polyphenolic amino acids and evaluation of their radical-scavenging activity

• Autor(a) principal: Monteiro, Luís S.
• Data de Publicação: 2019
• Outros Autores: Paiva-Martins, Fátima, Oliveira, Sandra, Machado, Inês, Costa, Marlene
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/72832
• topic: Polyphenolic amino acids; Hydroxyphenylglycines; Cell-penetrating peptides; Ugi reaction; diHydroxyphenylglycyl peptides; Radical-scavenging activity; Oxidation potential; Ciências Naturais::Ciências Químicas; Science & Technology

A simple and efficient procedure for the synthesis of N-acyl 4-hydroxy, 4-hydroxy-3-methoxy and 3,4-dihydroxy phenylglycine amides by a strategy based on the multicomponent Ugi reaction is proposed. Hydroxybenzaldehyde derivatives were reacted with 4-methoxybenzylamine, cyclohexyl isocyanide and benzoic acid or 2-naphthylacetic acid to give Ugi adducts that were treated with trifluoroacetic acid yielding N-acyl hydroxyphenylglycine amides in good yields. The same procedure using as acid component protocatechuic acid or hydrocaffeic acid gave N-catechoyl 3,4-dihydroxyphenylglycine amides. The use of N-benzyloxycarbonylglycine as acid component allowed the preparation of a 3,4-dihydroxyphenylglycyl dipeptide derivative. Radical-scavenging activity studies of the polyphenolic amino acid derivatives showed a sharp increase in activity with the increase in number of hydroxyl or catechol groups present. Cyclic voltammetry experiments established a correlation between oxidation peak potentials and the radical-scavenging activity.