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Chemistry of thienopyridines. XXIII. Mass spectra of some N ‐oxides, sulfoxides, and sulfones
Author(s) -
Klemm L. H.,
Rottschaefer Susan,
Merrill R. E.
Publication year - 1975
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570120631
Subject(s) - chemistry , radical , carbon monoxide , fragmentation (computing) , mass spectrum , oxide , medicinal chemistry , oxygen , photochemistry , inorganic chemistry , organic chemistry , ion , catalysis , computer science , operating system
The mass spectral fragmentation patterns of a series of thienopyridine N ‐oxides, S ‐oxides, and S,S ‐dioxides were elaborated as a means of structural determination. Observation of a significant (M‐16) peak is diagnostic for the presence of either an N ‐oxide or an S ‐oxide function (indistinguishable from one another by this method) but does not occur for an S,S ‐dioxide function. For a substituted thieno[2,3‐ b ]pyridine 7‐oxide, structural rearrangement to a pyridone (followed by emission of carbon monoxide or formyl radical) or side‐chain fission may be competitive with de‐ N ‐oxygenation. For two tricyclic parent S ‐oxides, rearrangement and de‐ S ‐oxygenation are competing initial processes. For parent S,S ‐dioxides structural rearrangement precedes fragmentation, wherein the oxygen is ejected in such forms as sulfur monoxide, carbon monoxide, formyl or cyanate radicals, and ketene.