2,4,8,10-四氧杂螺[5.5]十一烷的结构研究

Investigation on the Structure of 2,4,8,10-Tetraoxaspiro[5.5]undecanes

分别以烷基酮、芳基酮和季戊四醇为原料,环己烷或甲苯为溶剂,对甲苯磺酸为催化剂,合成了一系列具有不同相似度取代基的2,4,8,10-四氧杂螺[5.5]十一烷化合物。以螺环亚甲基氢为探针,通过改变螺环端基取代基的相似度,考察~1H NMR谱图中的峰形变化,揭示取代基与构象之间的构效关系。结果表明,两个氧杂六元环均为椅式构象,随着取代基相似度逐渐增加,椅式构象翻转速度加快,~1H NMR谱中螺环亚甲基氢的峰数目逐渐减少且化学位移分布区间逐渐减小,直至取代基团完全相同时呈现为一个单峰。

A series of 2,4,8,10-tetraoxaspiro[5.5]undecanes with different similarity of substituents were synthesized by reactions of pentaerythritol with aliphatic or aromatic ketones in cyclohexane or toluene using p-toluenesulfonic acid as the catalyst.Using the protons on spirocyclic methylenes as a probe,the structure-activity relationship between substituent and conformation was revealed by investigating the changes of peak shape in 1 H NMR spectra when the similarity of spirocyclic substituents were changed.The results illustrated that both of the two oxa-six-membered rings adopt chair conformations.With the increasing of similarities of substituents,the speeds of conformational reversal were increased,which conducted that the peak numbers of protons on spirocyclic methylenes were decreased and the distribution interval of chemical shift were shortened to a single peak until the substituents were the same in 1 H NMR spectra.