全合成左旋士的宁六种关键中间体的电喷雾离子阱质谱研究

Study on the Electrospray lonization Ion Trap Mass Spectra of Six Key Intermediates Related to the Total Synthesis of ( - )-Strychnine

采用电喷雾离子阱质谱法(ESI—MS)对不对称全合成左旋士的宁的六种中间体进行了深入探讨,获得了它们的结构碎片信息,通过比较它们的异同对其质谱裂解途径进行解析。结果表明:以正离子检测方式下可以得到较强的准分子离子[M+H]+峰,并检测到各自少量的加合离子。它们的(+)ESI—MSn(n=1～3)质谱主要产生氧醚键C-O和硫醚键S-C断裂的碎片。这些特征为全合成士的宁的关键中间体及其结构类似物的结构推断提供了有力的证据,有助于提高合成工作效率。

To investigate the mass spectrometric characteristics of six key intermediates related to the total synthesis of ( - )-strychnine, their mass spectra were obtained using elec-trospray ionization ion trap mass spectrometer (ESI-MS) in a multi-stage MS full scan mode performed on a Finnigan LCQ. The mass spectra were interpreted mainly by comparing the fragments of six compounds, and their fragmentation patterns were proposed. The results indicated the strong pseudomolecular ions were obtained in the positive mode and a small number of adduct ions were found. The positive ion proposed full scan ESI-MSn(n= 1-3) of each compound gave characteristic fragment ions formed through cleavage of the C-O bond and S-C bond in their structures. These characteristics can be applied further to the structure elucidation of the key intermediates and the analogues related to the total synthe-