ELECTRON IONIZATION MASS-SPECTROMETRY OF SPIROEPOXIDES GENERATED FROME-3-ARYLIDENEFLAVANONES

The electron-impact induced decomposition of some spiroepoxides prepar ed from E-3-arylideneflavanones has been examined by means of low- and high-resolution mass spectrometry, mass-analysed ion kinetic energy ( MIKE) spectrometry and collision-induced dissociation (CID) experiment s. The compounds studied were found to undergo a rearrangement reactio n resulting in a very intense odd-electron ion. The MIKE and CID-MIKE spectra of this type of ion generated from the unsubstituted epoxide p roved to be identical to those of the molecular ion of trans-stilbene. The isomerization of epoxides to the corresponding carbonyl compounds prior to fragmentation was not observed.