Conformational properties of ascydiacyclamide analogues with cyclic α-amino acids instead of oxazoline residues
作者:Akiko Asano、Shohei Numata、Takeshi Yamada、Katsuhiko Minoura、Mitsunobu Doi
DOI:10.1016/j.bmc.2017.10.029
日期:2017.12
ASC analogues [cyclo(-Ile-Xxx-d-Val-thiazole-)2] in which Pro or a homologue was substituted for oxazoline: [Pro]ASC (Xxx: proline), [Aze]ASC (Xxx: (S)-Azetidine-2-carboxylic acid), [Pip]ASC (Xxx: (S)-Piperidine-2-carboxylic acid) and [ΔPro]ASC (Xxx: (S)-3-pyrroline-2-carboxylic acid) to explore their potential to serve as substitutes for the oxazoline ring. The conformations of these analogues were
顺式二环酰胺[ASC,环(-Ile-恶唑啉-d - Val-噻唑-)2 ]是从被膜中分离出的环状八肽。我们设计了ASC类似物[cyclo(-Ile-Xxx- d -Val-噻唑-)2 ],其中Pro或同系物取代了恶唑啉:[Pro] ASC(Xxx:脯氨酸),[Aze] ASC(Xxx:(S)-氮杂环丁烷-2-羧酸),[Pip] ASC(Xxx:(S)-哌啶-2-羧酸)和[ΔPro] ASC(Xxx:(S)-3-吡咯啉-2-羧酸)探索它们作为恶唑啉环替代物的潜力。使用X射线衍射检查了这些类似物的构象,11 H NMR和CD光谱。在晶体状态和溶液状态下,[Pro] ASC,[Aze] ASC和[ΔPro] ASC的构型都是具有两个反酰亚胺键并被两个分子内氢键稳定的新型方形结构。[Pip] ASC的晶体结构为顺式和反式折叠构型酰亚胺键。[Pip] ASC溶液中存在三种异构体(cc,ct和tt)。