Premium
Electron impact induced fragmentation of dihydro‐1,4‐dithiines. 2,3‐Substituted 5,6‐dihydro‐l,4‐dithiines
Author(s) -
Nevalainen Vesa,
Vainiotalo Pirjo
Publication year - 1987
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210220903
Subject(s) - fragmentation (computing) , chemistry , ion , electron ionization , sulfur , ring (chemistry) , electron , medicinal chemistry , stereochemistry , crystallography , photochemistry , organic chemistry , ionization , physics , quantum mechanics , computer science , operating system
In the electron impact induced fragmentation of 2,3‐disubstituted 5,6‐dihydro‐1,4‐dithiines, the most important cleavage of the heterocyclic ring occurs via the retro‐Diels‐Alder type of reaction. The further fragmentation of the resulting radical cation gives rise to substitutes thiocarbonyl cations. This fragmentation favours formations of ions in which the electron‐deficient carbon‐sulphur triple bond is stabilized by an electron‐releasing group. The ring fragmentation was observed to be dependent on the nature of the 3‐ and 2‐substituents of the ring when a series of 3‐ and 2‐substituted 5,6‐dihydro‐l,4‐dithiines was investigated. The fragmentation of dihydro‐l,4‐dithiines partly resembles the fragmentation of the corresponding dihydro‐l,4‐oxathiines. The presence of the two sulphur atoms in dihydro‐l,4‐dithiines give rise to more stable molecular ions than observed in the case of the dihydro‐1,4‐oxathiine analogues. Fragmentations of dihydro‐l,4‐dithiines can also involve extrusions of alkylradicals or HS‐radical from the heterocyclic rings of molecular ions.