Four fused nitrogen-containing ring systems were investigated by electrospray ionization-tandem mass spectrometry: Pyridazino-indoles, pyridazino-quinolines, a pyrimido-quinoline derivative and pyrimido-cinnolines. Fragmentation patterns of these compounds are discussed and compared. Several characteristic cross-ring fragments were formed mainly on the pyridazine and pyrimidine rings of the ring systems. The connected Cl, NO2 , Me, Ph and more extended heterocyclic substituents influenced the fragmentation.
Keywords: fragmentation; fused N-heterocycles; pyridazino-indoles; pyridazino-quinolines; pyrimido-cinnolines; pyrimido-quinolines; tandem mass spectrometry.
© 2022 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons Ltd.