Synthesis and Conformational Analysis of Alternately <i>N</i>-Alkylated Aromatic Amide Oligomers
作者:Ko Urushibara、Hyuma Masu、Hirotoshi Mori、Isao Azumaya、Tomoya Hirano、Hiroyuki Kagechika、Aya Tanatani
DOI:10.1021/acs.joc.8b02045
日期:2018.12.7
Alternately N-alkylated aromatic amides such as 1–3 bearing various side chains were designed and synthesized as novel helical foldamers. The CD spectra of oligomers with chiral side chains showed a positive Cotton effect, which indicates that these oligomers take helical conformations in solution. The CD intensity gradually increased with increasing chain length, and pentamer 3d showed remarkably
交替Ñ烷基化的芳族酰胺,例如1 - 3轴承的各种侧链被设计并作为新颖的螺旋状foldamers合成。具有手性侧链的低聚物的CD光谱显示出正的Cotton效应,这表明这些低聚物在溶液中呈螺旋构象。CD强度随着链长的增加而逐渐增加,五聚体3d在氯仿中显示出非常强的CD信号。与聚(p - N-烷基苯甲酰胺)s的情况相反,UV光谱的吸收最大值随着链长的增加而逐渐红移。基于1a晶体结构的低聚物结构优化因为单体单元支持具有大空腔的螺旋结构的形成,并且还暗示了在仲酰胺之间形成分子内氢键。计算结果与观察到的光谱特征一致。