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Unimolecular and collision‐induced dissociation reactions of peracetylated methyl glucopyranoside
Author(s) -
Guevremont Roger,
Pathak Ved P.,
Wright Jeffrey L. C.
Publication year - 1990
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.1210250204
Subject(s) - chemistry , ketene , fragmentation (computing) , dissociation (chemistry) , collision induced dissociation , substituent , methyl acetate , medicinal chemistry , methyl radical , anomer , stereochemistry , photochemistry , mass spectrometry , organic chemistry , tandem mass spectrometry , radical , acetic acid , chromatography , computer science , operating system
The mechanism of the collision‐induced fragmentation of peracetylated methyl‐α‐D‐glucopyranoside was investigated using deuterium‐labelled acetates and sequential mass spectrometry. Loss of the substituent at C(1), the anomeric carbon, yields an ion of m/z 331, [C 14 H 19 O 9 ] + . This ion further dissociates via two pathways, the first including m/z 271, [C 12 H 15 O 7 ] + , 169, [C 8 H 9 O 4 ] + and 109, [C 6 H 5 O 2 ] + , and the second including m/z 211, [C 10 H 11 O 5 ] + , 169, [C 8 H 9 O 4 ] + and 127 [C 6 H 7 O 3 ] + . The first path proceeds via loss of acetate at C(3), followed by a single‐step concerted loss of acetates from C(2) and C(4), and ending with loss of acetate from C(6). The second path proceeds predominantly via loss of acetates from C(3) and C(4), elimination of ketene from the C(2)‐acetate and finally loss of ketene from the acetate at C(6). This path is also characterized by an ill‐defined series of parallel decomposition reactions involving acetates from other sites on the molecule. At low collision energy, and in the absence of collision gas (unimolecular reaction conditions), the former pathway predominates; m/z 331 dissociates via loss of acetate at C(3), followed by a single‐step concerted loss of acetates from C(2) and C(4).