Department of Chemistry, Faculty of Science, Ochanomizu University, Tokyo, Japan.
Chirality. 2011;23 Suppl 1:E84-90. doi: 10.1002/chir.21010. Epub 2011 Oct 14.
Aromatic N,N'-dimethylated urea exists in (cis, cis) form, both in the crystal and in solution, and this structure can be utilized to construct intramolecular aromatic multilayered oligomers. These structures show helical conformation with all-R or all-S axis chirality, when the benzene rings are connected at the meta positions. To investigate the dynamic conformational behavior of such aromatic multilayered ureas in various solvents, we synthesized tetra(m-phenylurea) 3 bearing two chiral N-2-(methoxyethoxyethoxy)propyl groups and six N-methoxyethoxyethyl groups. The high solubility of compound 3 enabled its analysis in various solvents, including water. The CD spectra of compound 3 showed broad electronic absorption with high temperature-dependency, owing to the induction of handedness, in acetonitrile, chloroform, and methanol. In water, the CD signals of compound 3 indicated the presence of similar helical structure, but temperature-dependency was not observed.
芳香族 N,N'-二甲脲以（顺式，顺式）形式存在于晶体和溶液中，这种结构可用于构建分子内芳香多层寡聚物。当苯环连接在间位时，这些结构表现出全 R 或全 S 轴手性的螺旋构象。为了研究此类芳香多层脲在各种溶剂中的动态构象行为，我们合成了带有两个手性 N-2-（甲氧基乙氧基乙氧基）丙基和六个 N-甲氧基乙氧基乙基的四（间苯脲）3。化合物 3 的高溶解度使其能够在包括水在内的各种溶剂中进行分析。化合物 3 在乙腈、氯仿和甲醇中的 CD 光谱显示出宽的电子吸收，具有高温依赖性，这是由于手性的诱导。在水中，化合物 3 的 CD 信号表明存在类似的螺旋结构，但没有观察到温度依赖性。
