奥美拉唑核磁共振结构解析中化学交换对信号的影响

EFFECT OF CHEMICAL EXCHANGE ON NMR SIGNALS FOR STRUCTURE ANALYSIS OF OMEPRAZOLE

利用HSQC技术对2种溶剂体系下奥美拉唑(Omeprazole)分子中特定碳原子的横向弛豫时间T2进行了测定.测定结果显示2种不同溶剂体系下的T2值差别很大,证明了在DMSO-d6溶剂体系中该化合物存在一个分子内的化学交换过程.实验通过改变溶剂体系的手段抑制了化学交换现象,获得了理想的核磁谱图,并顺利地完成了奥美拉唑分子的结构确定,还对这一化学交换过程导致NMR信号异常的原因进行了探讨.

With HSQC technique, the transverse relaxation time T2 was determined for certain carbon nuclear on the molecule of Omeprazole in two solvent systems. The results showed that the values of T2 were different in the two systems. Therefore, it could be confirmed that there was an intra-molecular chemical exchange as Omeprazole was dissolved in DMSO-d6. In this work, the chemical exchange was suppressed when a different solvent system was used. Thus, a set of ideal NMR spectrum were obtained and the molecular structure of Omeprazole was determined properly. The effect of the chemical exchange on NMR signals is discussed as well.