Gas-phase fragmentation of γ-lactone derivatives by electrospray ionization tandem mass spectrometry

• Published in: Journal of mass spectrometry. 2009-12, Vol.44 (12), p.1733-1741
• Main Authors: Crotti, Antonio E.M, Bronze-Uhle, Erika S, Nascimento, Paulo G.B.D, Donate, Paulo M, Galembeck, Sérgio E, Vessecchi, Ricardo, Lopes, Norberto P
• Format: Article
• Language: English
• Subjects: 4-Butyrolactone - chemistry; carbonyl compounds; Chemical Phenomena; Chemistry; collision-induced dissociation; Exact sciences and technology; gas-phase ion chemistry; Mass spectrometry; Organic chemistry; Reactivity and mechanisms; Spectrometry, Mass, Electrospray Ionization - methods; Tandem Mass Spectrometry - methods; theoretical calculations; Thermodynamics; γ-butyrolactone
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/jms.1682

Fragmentation reactions of β-hydroxymethyl-, β-acetoxymethyl- and β-benzyloxymethyl-butenolides and the corresponding γ-butyrolactones were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) using collision-induced dissociation (CID). This study revealed that loss of H₂O [M + H -18]⁺ is the main fragmentation process for β-hydroxymethylbutenolide (1) and β-hydroxymethyl-γ-butyrolactone (2). Loss of ketene ([M + H -42]⁺) is the major fragmentation process for protonated β-acetoxymethyl-γ-butyrolactone (4), but not for β-acetoxymethylbutenolide (3). The benzyl cation (m/z 91) is the major ion in the ESI-MS/MS spectra of β-benzyloxymethylbutenolide (5) and β-benzyloxymethyl-γ-butyrolactone (6). The different side chain at the β-position and the double bond presence afforded some product ions that can be important for the structural identification of each compound. The energetic aspects involved in the protonation and gas-phase fragmentation processes were interpreted on the basis of thermochemical data obtained by computational quantum chemistry. Copyright © 2009 John Wiley & Sons, Ltd.