We designed and synthesized aromatic polyamides with a diphenylacetylene backbone, α-DPA and β-DPA, bearing (S)-α- and (S)-β-methyl-substituted triethyleneglycol (TEG) side chains, respectively, and examined their conformations in solution. Both polymers exhibit strong, solvent polarity-dependent circular dichroism spectra, which indicated that they take helical conformations in low-polarity solvents. The spectra were mirror images, depending on the chiral position of the side chains. Thus, the polyamide α-DPA bearing (S)-α-methyl-substituted TEG groups takes a left-handed helical conformation, while the polyamide β-DPA with (S)-β-methyl-substituted TEG groups takes a right-handed helical conformation. The difference in the screw sense of α-DPA and β-DPA would be caused by the steric interaction between the main chain and the side chain, as observed in poly(p-benzamide) possessing (S)-β-methyl-substituted TEG side chains (β-PA) because the large cavity of the helical structure of DPA would disturb the solvophobically induced helical folding. Detailed conformational analyses of the oligoamides 6-12 with β-methyl-substituted TEG groups were conducted. Theoretical calculations indicated that the oligoamides with β-methyl-substituted TEG groups exist in a helical conformation with a cavity of 7 Å in diameter. The 1H NMR spectra of the oligomers revealed interactions with small anions such as chloride and acetate anions and with pyridinium cations.

中文翻译：

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带有二苯乙炔骨架的螺旋芳族酰胺折叠剂的开发。

我们设计并合成了带有二苯乙炔主链，α-DPA和β-DPA，分别带有（S）-α-和（S）-β-甲基取代的三乙二醇（TEG）侧链的芳族聚酰胺，并检查了它们的构象。解。两种聚合物均显示出强的，与溶剂极性有关的圆二色性光谱，这表明它们在低极性溶剂中呈螺旋构象。光谱是镜像的，取决于侧链的手性位置。因此，具有（S）-α-甲基取代的TEG基团的聚酰胺α-DPA具有左旋螺旋构象，而具有（S）-β-甲基取代的TEG基团的聚酰胺β-DPA具有右旋螺旋构象。螺旋构象。α-DPA和β-DPA的螺丝感不同是由主链和侧链之间的空间相互作用引起的，如在具有（S）-β-甲基取代的TEG侧链（β-PA）的聚对苯甲酰胺中所观察到的，这是因为DPA螺旋结构的大空腔会干扰溶剂化引起的螺旋折叠。对带有β-甲基取代的TEG基团的寡酰胺6-12进行了详细的构象分析。理论计算表明，具有β-甲基取代的TEG基团的低酰胺以螺旋构象存在，其空腔的直径为7。低聚物的1 H NMR光谱显示与小阴离子（如氯离子和乙酸根阴离子）和吡啶鎓阳离子发生相互作用。对带有β-甲基取代的TEG基团的寡酰胺6-12进行了详细的构象分析。理论计算表明，具有β-甲基取代的TEG基团的低酰胺以螺旋构型存在，其空腔的直径为7。低聚物的1 H NMR光谱显示与小阴离子（如氯离子和乙酸根阴离子）和吡啶鎓阳离子发生相互作用。对具有β-甲基取代的TEG基团的寡酰胺6-12进行了详细的构象分析。理论计算表明，具有β-甲基取代的TEG基团的低酰胺以螺旋构型存在，其空腔的直径为7。低聚物的1 H NMR光谱显示与小阴离子（如氯离子和乙酸根阴离子）和吡啶鎓阳离子发生相互作用。