On alkaloids. XIII. On the mass spectra of vindorosine

Isolation and13C-NMR Studies on Cathovaline, an Alkaloid from the Leaves ofCatharanthus roseus

“…As the 13C-NMR of cathovaline had not been reported previously, it was dicided to record and study it. The 13C-NMR spectrum (CDCI3) was in agreement with the structure proposed earlier on the basis of its 1H-NMR and spectroscopic comparison with vindoline (7,8) and vindorosine (9,10). The assignment of 13C-resonance signals are shown in Table I.…”

Structure Elucidation and Chemistry of Catharanthus Alkaloids II. Isolation and Partial Structure of Catharine, a Dimeric Indole Alkaloid From C. Zanceus and C. Roseus

“…The m/e 763 peak represents a loss of 59 mass units, or a carbomethoxy group. Previous mass spectral degradations of vindoline (16,17) are also evident here. The m/e 822 to m/e 662 (11) transition (Scheme I), with loss of 160 mass units, indicates ABD cleavage to give the fragment IIa.…”

Structure elucidation of indole–indoline type alkaloids: A retrospective account from the point of view of current NMR and MS technology

“…Fragment B (m/z 355) corresponds to the velbanamine part of the molecule. Fragment m/z 282, which is a characteristic fragment of the vindoline part, was rationalized by the structure E [13,14,16]. A Retro Diels-Alder fragmentation (G) can also be observed for VLB resulting in the fragment at m/z 650 (m/z 651 is more intense in the mass spectrum).…”

“…On the basis of the above fragmentation mechanism fragment L is produced exclusively by loss of a CH 3 COOH from position C (17). In our own work aimed at identifying new VLB-and VCR-related impurities, an in-depth high-resolution tandem MS analysis of VLB and VCR was performed [45], and on the basis of MS n experiments we could prove that parallel to the loss of CH 3 COOH, in a similar ratio the loss of HCOOCH 3 can also occur from C (16). This observation could be utilized when we had to identify a VLB impurity by on-line LC-MS/MS in which the structural alteration affected the C(16)-COOMe moiety [46].…”

“…4), a major alkaloid of C. roseus [13][14][15][16] and a building block of bisindole alkaloids. A comparative mass spectrometric study suggested that vindoline possesses an aspidospermine skeleton.…”