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Mass Spectrometric Studies of the Gas Phase Retro- Michael Type Fragmentation Reactions of 2-Hydroxybenzyl- N -Pyrimidinylamine Derivatives
- Source :
-
Journal of the American Society for Mass Spectrometry . Sep2005, Vol. 16 Issue 9, p1561-1573. 13p. - Publication Year :
- 2005
-
Abstract
- The gas-phase fragmentation reactions of 2-hydroxybenzyl-N-pyrimidinylamine derivatives (Compounds 1 to 6 ), the O-N-type acid-catalyzed Smiles rearrangement products of 2-pyrimidinyloxy-N-arylbenzylamine derivatives, have been examined via positive ion matrix-assisted laser desorption/ionization (MALDI) infrared multiphoton dissociation (IRMPD) mass spectrometry in FT-ICR MS and via negative ion electrospray ionization (ESI) in-source collision-induced dissociation (CID) mass spectrometry, respectively. The major fragmentation pathway of protonated 1 to 6 gives the F ions under IRMPD; theoretical results show that the retro-Michael reaction channel is more favorable in both thermodynamics and kinetics. This explanation is supported by H/D exchange experiments and the MS/MS experiment of acetylated 1 . Deprotonated 1 to 6 give rise to the solitary E ions (aromatic nitrogen anions) in the negative ion in-source CID; theoretical calculations show that a retro-Michael mechanism is more reasonable than a gas-phase intramolecular nucleophilic displacement (S N 2) mechanism to explain this reaction process. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 10440305
- Volume :
- 16
- Issue :
- 9
- Database :
- Academic Search Index
- Journal :
- Journal of the American Society for Mass Spectrometry
- Publication Type :
- Academic Journal
- Accession number :
- 18234511
- Full Text :
- https://doi.org/10.1016/j.jasms.2005.05.006