Mass spectrometric study on 2‐amino‐as‐triazino[6,5‐c]quinoline and some of its derivatives

Electron impact induced fragmentations of 2-amino-as-triazino[6,5-c]quinoline and its 2-methylamino, 2-dimethylamino and 2-benzylamino analogues have been investigated. The main primary decomposition route of both the singly and the doubly charged molecular ions is the N2 loss. For the singly charged ions the critical energy of this reaction is 110±10 kJ mol−1 and the kinetic energy release is 61±4 kJ mol−1. For the doubly charged ions these values are 90±10 kJ mol−1 and 5±2 kJ mol−1, respectively, indicating a significantly different reaction profile. The further fragmentation of [MN2]+˙ ions consists of radical eliminations from the 2-amino group with cleavages of the α- and β-bonds. Here a significant substituent effect is eliminations found suggesting an intramolecular cyclization reaction with a substituent migration. D and 15N labelling experiments have shown a minor extent of randomization of the labelled atoms and the occurrence of other hidden skeletal rearrangements during the fragmentation.