Helical Structures of Cyclopentene-based α,α-Disubstituted α-Amino Acid Homopeptides
作者:Masakazu Tanaka、Haruka Yakabi、Haruki Nakatani、Atsushi Ueda、Mitsunobu Doi、Makoto Oba
DOI:10.2533/chimia.2018.848
日期:——
The cyclopentene-based α,α-disubstituted α-amino acid Ac5c= and its homopeptides, up to nonapeptides, were synthesized. The side-chain cyclopentene was expected to become symmetric, the Cα-carbon to be puckered, and other Cβ, Cβ', Cγ, Cγ'-carbons to be coplanar. As expected, side-chain cyclopentene conformations became symmetric and Cα-carbons were puckered. Conformational studies using FT-IR absorption
合成了基于环戊烯的α,α-二取代α-氨基酸Ac5c=及其同肽直至九肽。预计侧链环戊烯将变得对称,Cα-碳将皱褶,而其他Cβ、Cβ'、Cγ、Cγ'-碳将共面。正如预期的那样,侧链环戊烯构象变得对称,Cα-碳发生褶皱。使用 FT-IR 吸收、1H NMR 光谱和 X 射线晶体学分析进行的构象研究表明,Ac5c= 同肽没有形成平面构象,而是呈现 310 螺旋结构,类似于基于环戊烷的 α,α-二取代 α-氨基酸同肽。