title: Fragmentation studies of synthetic 2-acylamino-1,4-naphthoquinones by electrospray ionization mass spectrometry.
abstract: We report here the fragmentation mechanism for five 2-acylamino-1,4-naphthoquinone derivatives using electrospray ionization tandem mass spectrometry (ESI-MS/MS). Analyses were performed on a low-resolution, triple-quadrupole mass spectrometer. Fragmentation pathways for protonated molecular derivatives 2-acylamino-1,4-naphthoquinone [M+H]+ are proposed on the basis of theoretical calculations. There is evidence that the nitrogen atom is the protonation site, based on the nucleophilic atomic indices.
authors.affiliation: Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Brasil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Vessecchi
authors.forename: Paulo G B D
authors.initials: PG
authors.lastname: Nascimento
authors.forename: José N C
authors.initials: JN
authors.lastname: Lopes
authors.forename: Norberto P
authors.initials: NP
authors.lastname: Lopes
mesh_terms: D007202:Indicators and Reagents; D009285:Naphthoquinones / Q000138:chemical synthesis / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D007202:Indicators and Reagents; D009285:Naphthoquinones; D011522:Protons; D009584:Nitrogen