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Structural assignment of isomeric 2‐(2‐quinolinyl)‐1 H ‐indene‐1,3(2 H )‐dione mono‐ and disulfonic acids by liquid chromatography electrospray and atmospheric pressure chemical ionization tandem mass spectrometry
Author(s) -
Weisz Adrian,
Andrzejewski Denis,
Fales Henry M.,
Mandelbaum Asher
Publication year - 2001
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.205
Subject(s) - chemistry , tandem mass spectrometry , mass spectrometry , fragmentation (computing) , moiety , electrospray ionization , chemical ionization , indene , dissociation (chemistry) , atmospheric pressure chemical ionization , medicinal chemistry , collision induced dissociation , ion , analytical chemistry (journal) , ionization , stereochemistry , chromatography , organic chemistry , computer science , operating system
Positionally isomeric 2‐(2‐quinolinyl)‐1 H ‐indene‐1,3(2 H )‐dione mono‐ and disulfonic acids give rise to similar electrospray ionization (ESI) and atmosphere pressure chemical ionization (APCI) mass spectra, which show very abundant MH + ions and negligible fragmentation. The MH + ions of these isomeric acids exhibit notably different behavior under collision‐induced dissociation (CID) conditions. The acids with a sulfonic group at position 8′ in the quinoline moiety, adjacent to the N‐atom, exhibit highly abundant [MH − H 2 SO 3 ] + ions ( m / z 272 for the mono‐ and m / z 352 for the disulfonic acids), which are of lower abundance in the CID spectra of isomers with the SO 3 H group at other positions, remote from the nitrogen atom. The latter isomers undergo efficient eliminations of SO 3 and HSO 3 . The isomeric diacids with one SO 3 H group at position 4 of the indene‐1,3(2 H )‐dione moiety, adjacent to one of the carbonyl groups, undergo highly efficient elimination of H 2 O. Mechanistic pathways, involving interactions between adjacent groups, are proposed for the above regiospecific fragmentations. Pronounced different behavior has been also observed in negative ion tandem mass spectrometric measurements of the sulfonic acids. The distinctive behavior of the isomeric acids was strongly pronounced when the measurements were performed with an ion trap mass spectrometer (LCQ), and much less so with a triple‐stage quadrupole instrument (TSQ). Published in 2001 by John Wiley & Sons, Ltd.