Synthesis and conformational analysis of hybrid α/β-dipeptides incorporating S-glycosyl-β2,2-amino acids
- García-González, I. 1
- Mata, L. 1
- Corzana, F. 1
- Jiménez-Osés, G. 2
- Avenoza, A. 1
- Busto, J.H. 1
- Peregrina, J.M. 1
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1
Universidad de La Rioja
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2
University of California Los Angeles
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ISSN: 0947-6539
Año de publicación: 2015
Volumen: 21
Número: 3
Páginas: 1156-1168
Tipo: Artículo
beta Ver similares en nube de resultadosOtras publicaciones en: Chemistry - A European Journal
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Resumen
We synthesized and carried out the conformational analysis of several hybrid dipeptides consisting of an α-amino acid attached to a quaternary glyco-β-amino acid. In particular, we combined a S-glycosylated β2,2-amino acid and two different types of α-amino acid, namely, aliphatic (alanine) and aromatic (phenylalanine and tryptophan) in the sequence of hybrid α/β-dipeptides. The key step in the synthesis involved the ring-opening reaction of a chiral cyclic sulfamidate, inserted in the peptidic sequence, with a sulfur-containing nucleophile by using 1-thio-β-D-glucopyranose derivatives. This reaction of glycosylation occurred with inversion of configuration at the quaternary center. The conformational behavior in aqueous solution of the peptide backbone and the glycosidic linkage for all synthesized hybrid glycopeptides was analyzed by using a protocol that combined NMR experiments and molecular dynamics with time-averaged restraints (MD-tar). Interestingly, the presence of the sulfur heteroatom at the quaternary center of the β-amino acid induced θ torsional angles close to 180° (anti). Notably, this value changed to 60° (gauche) when the peptidic sequence displayed aromatic α-amino acids due to the presence of CH-π interactions between the phenyl or indole ring and the methyl groups of the β-amino acid unit.