Minor Alkaloids in Commercial Samples of Colchicine

Mass spectrometric study of colchicine and its synthetic derivatives 10-alkylthiocolchicines

“…10,13 As shown in Scheme 1, the molecular ions of compounds 1-5 studied can lose CO and NH 2 COCH 3 molecules to form odd-electron ions b, g and h. Ion h, which is very abundant for all compounds, undergoes further fragmentation by a few pathways. Although it is difficult to propose a detailed mechanism for the loss of • CH 3 from the ion h, it seems to be reasonable that the dominant structure of [h -…”

“…10,13 According to the linked-scan at constant B 2 /E spectra, the fragment ion p may be obtained from the precursor ion c by the elimination of the NH 2 COCH 3 molecule. This investigation was also undertaken to find out whether it is possible to differentiate between the isomeric 10-n-propylthiocolchicine (3) and 10-thio-isopropylcolchicine (4) on the basis of the relative abundance of the selected fragment ions ( Figure 2, Table 2).…”

“…9 Some of these derivatives have been characterized by means of mass spectra methods, but the mass spectrometry of 10-alkylthiocolchcines has not been published so far, while the EI and ESI mass spectra of colchicine itself are known and described in chemical literature. 10,11 The MS methods have been used to establish fragmentation patterns of some colchicine analogues and for detection and identification of components in Colchicum species, whereas mass spectrometry with liquid chromatography, LC/ESI-MS/MS or LC-APCI-MS, have found application in detection of colchicine in sheep serum and milk and in human blood plasma. 10,[12][13][14][15][16][17][18] In the present work five 10-alkylthiocolchicine derivatives ( Figure 1) were investigated for the principal fragmentation pathways of the molecular ions using EI and protonated molecules using MALDI mass spectrometry.…”