Mechanistic Insight into the Lability of the Benzyloxycarbonyl (Z) Group in<i>N</i>-Protected Peptides under Mild Basic Conditions
作者:Marta Tena-Solsona、César A. Angulo-Pachón、Beatriu Escuder、Juan F. Miravet
DOI:10.1002/ejoc.201400154
日期:2014.6
protecting group undermildbasicconditions at room temperature is explained by a mechanism based on anchimeric assistance. It is found that the vicinal amide group stabilises the tetrahedral intermediate formed after nucleophilic addition of hydroxide to the carbonyl of the Z group. This effect operates in N-protected tripeptides and tetrapeptides but Z-protected dipeptides are stable under the same conditions
苄氧羰基 (Z) 保护基团在室温温和碱性条件下出乎意料的不稳定可通过基于嵌合辅助的机制来解释。发现邻酰胺基团稳定了在氢氧化物与 Z 基团的羰基亲核加成后形成的四面体中间体。这种效应在 N 保护的三肽和四肽中起作用,但 Z 保护的二肽在相同条件下是稳定的,因为邻位酰胺 NH 通过与末端羧酸根部分的分子内 H 键合而被阻断。
Tetrapeptidic Molecular Hydrogels: Self-assembly and Co-aggregation with Amyloid Fragment Aβ1-40
作者:Marta Tena-Solsona、Juan F. Miravet、Beatriu Escuder
DOI:10.1002/chem.201302651
日期:2014.1.20
A new family of isomeric tetrapeptides containing aromatic and polar amino acid residues that are able to form molecularhydrogels following a smooth change in pH is described. The hydrogels have been studied by spectroscopic and microscopic techniques showing that the peptide primary sequence has an enormous influence on the self‐assembly process. In particular, the formation of extended hydrophobic