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

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-