title: Gas-phase fragmentation of gamma-lactone derivatives by electrospray ionization tandem mass spectrometry.
abstract: Fragmentation reactions of beta-hydroxymethyl-, beta-acetoxymethyl- and beta-benzyloxymethyl-butenolides and the corresponding gamma-butyrolactones were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) using collision-induced dissociation (CID). This study revealed that loss of H(2)O [M+H-8](+) is the main fragmentation process for beta-hydroxymethylbutenolide (1) and beta-hydroxymethyl-gamma-butyrolactone (2). Loss of ketene ([M+H-42](+)) is the major fragmentation process for protonated beta-acetoxymethyl-gamma-butyrolactone (4), but not for beta-acetoxymethylbutenolide (3). The benzyl cation (m/z 91) is the major ion in the ESI-MS/MS spectra of beta-benzyloxymethylbutenolide (5) and beta-benzyloxymethyl-gamma-butyrolactone (6). The different side chain at the beta-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.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto-USP, Ribeirão Preto, SP, Brazil.
authors.forename: Antonio E M
authors.initials: AE
authors.lastname: Crotti
authors.forename: Erika S
authors.initials: ES
authors.lastname: Bronze-Uhle
authors.forename: Paulo G B D
authors.initials: PG
authors.lastname: Nascimento
authors.forename: Paulo M
authors.initials: PM
authors.lastname: Donate
authors.forename: Sérgio E
authors.initials: SE
authors.lastname: Galembeck
authors.forename: Ricardo
authors.initials: R
authors.lastname: Vessecchi
authors.forename: Norberto P
authors.initials: NP
authors.lastname: Lopes
mesh_terms: D015107:4-Butyrolactone / Q000737:chemistry*; D055598:Chemical Phenomena; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013816:Thermodynamics
chemical_list: D015107:4-Butyrolactone