Indole alkaloids mass spectroscopy

Results and data gathered on mass spectroscopy of various indole alkaloids have been summarized by Hesse (320). The derivation of the characteristic fragments of indolo[2,3-a]quinolizidines has been interpreted by Gribble and Nelson (321), who investigated C-3, C-5, C-6, C-20, and C-21 deuterated derivatives of octahydroindolo[2,3-a]quinolizine (1). Kametani et al. have observed and proved, with labeled compounds, a methyl transfer from the ester function of reserpine derivatives to the basic nitrogen atom during mass-spectroscopic measurement (322). 

The latest structure for VLR (leurosine, vinleurosine) (55) was obtained primarily by analytical methods like i.r., n.m.r., and mass spectroscopy. No structure has yet been proposed for VRD (leurosidine, vinrosidine), leurosivine, or rovidine. An additional number of dimeric indole bases (24 out of the total of 72 alkaloids isolated) have been obtained from Catharanthus, but they seem to be devoid of anti-tumour activity. 

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