A novel intramolecular hydrogen bonding between a side-chain pyridine ring and an amide hydrogen of the peptide backbone in tripeptides containing the new amino acid, α,α-di(2-pyridyl)glycine
摘要:
通过改进的 Ugi 反应合成了四种含有新型氨基酸α,α-二(2-吡啶基)甘氨酸(2Dpy)的三肽(Z-AA1-2Dpy-AA3-OMe;AA1, AA3 = Gly, Aib)。核磁共振分析清楚地表明,除 AA1、AA3 = Aib 的肽外,含 2Dpy 的三肽采用了一种独特的构象,在 2Dpy-NH 与一个吡啶氮之间以及 AA3-NH 与另一个吡啶氮之间有两个分子内氢键。这种构象迄今尚未见报道。另一方面,肽 Z-Aib-2Dpy-Aib-OMe 很可能采用δ-匝结构,该结构通过 2Dpy-NH 与一个吡啶氮之间以及 AA3-NH 与 Z 基团的 CO 之间的两个分子内氢键来稳定。
Tripeptides containing a novel alpha,alpha-disubstituted glycine with two pyridine rings, alpha,alpha-di(2-pyridyl)glycine (2Dpy), were synthesized by the solid-phase Ugi reaction using di(2-pyridyl)methanimine attached directly to a Rink amide resin. Thereby, yields of the tripeptides, Z-AA(1)-2Dpy-AA(3)-OMe (AA(1) and AA(3) = Gly or Aib), were markedly improved, compared with yields by the solution method. (C) 2004 Elsevier Ltd. All rights reserved.