Characteristic fragmentation behavior of some novel anti-calmodulin acridone derivatives studied by electrospray ionization tandem mass spectrometry

The mass spectroscopic behaviors of novel 4-fluoro N10-substituted acridones were studied by using positive ion electrospray ionization (ESI) with tandem mass spectrometry. Protonated molecular ions [M + H]+ were observed for all the compounds studied, and in the case of the parent 4-fluro acridone molecular ion [M]+ peak was obtained. The most interesting feature is that all the novel compounds predominantly gave nitrogen containing fragment ions. Tandem mass spectrometry was performed on these quasimolecular ions, and the product ions formed provided useful fragmentation patterns that were characteristic for the compounds. Fragmentation pathways and possible fragment ion structures are discussed. In order to obtain elemental composition, accurate mass measurements were performed.