含氮化合物的构型与构象变化对核磁共振图谱的影响

Effects of changes in conformation and configuration of N-containing compounds on NMR spactra

目的 寻找盐酸洛美利嗪等含氮化合物呈现特殊核磁图谱的内在原因。方法 假设这些化合物存在构型和构象的变化导致核磁图谱的复杂化。用核磁方法证实这种假设的可信性。结果与结论 盐酸洛美利嗪、盐酸西替利嗪两化合物的氮原子翻转形成两种椅式构象。在二甲亚砜溶液中其变换速度与核磁时标相近 ,无法测得确切的化学位移。所有谱线呈现不同程度的弥散 ,甚至坍塌、“消失”。加入少量水或升高测试温度降低了溶液的粘度 ,变换速度快于核磁时标 ,此时即可获得正常的图谱。芬氟拉明的氨基被樟脑酰胺化后限制了氮的 3个键的翻转 ,不对称氮的存在可产生另一对非对映异构体。其碳谱显示所有谱线倍增的特殊现象可得到合理的解释。

Aim To find the cause of abnormal NMR spectra of lomerizine dihydrochloride, cetirizine dihydrochloride and flenfluramine camphoramide. Methods Hypothesizing, in given conditions, there are changes of stereoisomeric conformation and configuration in structure of N-containing compounds, it resuts in abnormality of NMR spectra. By using the method of NMR, it is confirmed credibily. Results and Conclusion The moving balance exists between two chair conformations in lomerizine dihydrochloride and cetirizine...