title: Mass spectrometry of nitrosamines: rearrangement of nitrosobenzylmethylamine molecular ions with loss of OH-radicals investigated by deuterated derivatives.
abstract: Nitrosamines (R1R2NO) containing a certain R groups yield mass spectra with M+-OH fragments which can be accounted for by intramolecular hydrogen shift with subsequent cleavage of OH-radicals. As can be shown with mass spectra of specifically deuterated derivatives of nitrosobenzylmethylamine - nitrosobenzyltrideuteriomethylamine, alpha,alpha-nitrosodideuteriobenzylmethylamine and o,o',p-nitrosotrideuteri0-benzylmethylamine - hydrogen transfer within the molecular ion of nitrosobenzylmethylamine occurs selectively onto the  oxygen of the nitroso group from the benzylethylene group, probably via a five-membered cyclic transition state. Cleavage of OH radicals leads to formation of M+-17 ions, the stability of which can be explained by mesomerically stabilized cyclic diazirinium ions.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003903:Deuterium; D004128:Dimethylnitrosamine / Q000031:analogs & derivatives*; D005609:Free Radicals; D013058:Mass Spectrometry; D009602:Nitrosamines / Q000031:analogs & derivatives*; D013329:Structure-Activity Relationship
chemical_list: D005609:Free Radicals; D009602:Nitrosamines; D003903:Deuterium; D004128:Dimethylnitrosamine