790204-13-6Relevant articles and documents
Fragmentation pathways of eight nitrogen-containing bisphosphonates (BPs) investigated by ESI-MSn in negative ion mode
Qu, Zhibo,Chen, Xiaolan,Qu, Chen,Qu, Lingbo,Yuan, Jinwei,Wei, Donghui,Li, Huina,Huang, Xiaoying,Jiang, Yuqin,Zhao, Yufen
experimental part, p. 85 - 93 (2011/11/04)
Fragmentation pathways of eight nitrogen-containing bisphosphonates (BPs), including Pamidronate, Alendronate, and five corresponding acylated derivatives, and Risedronate, were investigated by electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry in negative ion mode. Characteristic fragment ions involved were formed by successive loss of water molecules, including α, β-unsaturated product ions formed by dehydration of the α-hydroxyl group and β-hydrogen, cyclic ions with P-O-P four-membered rings formed by dehydration of the two -OH groups attached to two phosphorus atoms, and cyclic phosphoramide ions with five- or six-membered rings formed by loss of water via an intramolecular nucleophilic substitution reaction, in which -NH2 (or -NH-) group on γ or δ carbon acted as the nucleophile to attack phosphorus atom of PO group at the initial stage. Another notable characteristic product ion [HP2O5]- at m/z 143, shown by all eight ESI-MS2 spectra, is a diagnostic ion of bisphosphonate group, formed from the four-membered ring ion containing P-O-P. Some additional fragmentation ions were produced from chloroacetyl Alendronate, chloroacetyl Pamidronate, and Risedronate containing triple bond ions, formed by loss of water from the corresponding enol anions. The hydrogen/deuterium (H/D) exchange experiment, theoretical calculations, and the high-resolution mass spectrometry were appropriately employed to rationalize the proposed fragmentation pathways.
