2-substituted benzofuran fragment ion formation in the electron ionization mass spectra of 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepine derivatives. 1. Spirocyclization of the molecular ions in the gas phase.
The formation of 2-substituted benzo[b]furan ions in the electron ionization (EI) mass spectra of a series of 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepines has been studied by means of exact mass measurements and multiple-stage mass spectrometry conditions using an ion trap mass spectrometer. The proposed mechanism of formation of benzo[b]furan ions requires the formation of a spirocyclic cyclohexadienone system, which undergoes elimination of a cyclopentadienone molecule. A parallel with the chemical conversion of arylmethyl-substituted dibenzo(d,f)(1,3)dioxepines into an analogous spirocyclic system was also underlined.
Begala
Michela
M
Dipartimento Farmaco Chimico Tecnologico, Università di Cagliari, Via Ospedale 72, 09124 Cagliari, Italy.
Tocco
Graziella
G
Meli
Gabrielle
G
Podda
Gianni
G
Urru
Silvana A M
SA
D001572:Benzofurans / Q000737:chemistry*; D003510:Cyclohexanes / Q000737:chemistry*; D053138:Cyclohexenes; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D007477:Ions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013141:Spiro Compounds / Q000737:chemistry*
D001572:Benzofurans; D003510:Cyclohexanes; D053138:Cyclohexenes; D007477:Ions; D013141:Spiro Compounds; C507608:cyclohexadienone