Novel tandem hydrogen migrations across five chemical bonds for 1,4-dihydropyridine using electrospray ionization FT-ICR mass spectrometry

The electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS) was applied to investigate the characteristic fragmentation patterns of 1, 4-dihydropyridines using collision-induced dissociation (CID) method in positive ion mode. The intra-molecular tandem hydrogen atom migrations were observed with gas phase Na+/H+ exchange by crossing five chemical bonds for 1,4-dihydropyridines. The possible rearrangement mechanisms were proposed for the first time, and the key structure of product ions were confirmed by high resolution tandem mass spectrometry and in solution hydrogen/deuterium labeling. The novel tandem hydrogen migration could be considered as a general fragmentation pattern for 1,4-dihydropyridine drugs because of their intrinsic chemical structures. (C) 2016 Elsevier B.V. All rights reserved.