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Ring opening of the molecular ion of 5(4 H )‐oxazolone
Author(s) -
Császár Attila G.,
Somogyi Árpád,
Pócsfalvi Gabriella,
Traldi Pietro
Publication year - 1992
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.1210271204
Subject(s) - oxazolone , endothermic process , mndo , ring (chemistry) , chemistry , ion , ab initio , computational chemistry , exothermic reaction , crystallography , molecule , organic chemistry , adsorption
Quantum chemical calculations were carried out at several theoretical levels (semi‐empirical, MNDO; ab initio , 3–21G SCF, 6–311G** SCF and DZP CISD) to investigate the ring‐opening process of and the loss of CO from the molecular ion of 5(4 H )‐oxazolone. The ring‐opening process is predicted to be slightly endothermic and the loss of CO from the open‐ring molecular ion to be slightly exothermic. Detailed population analysis calculations suggest the weakening of the lactonic CO bond in the closed‐ring molecular ion and weak carbon—carbon and nitrogen—(formy)—carbon bonds in the open form. Both the open‐ring molecular ion and the [M–CO] +· ion are suggested to be of distonic type.