Substituent effects in the fragmentation of acetanilides

Abstract

The mass spectra of a series of meta- and para-substituted acetanilides have been examined. Substituent effects have been used to provide information about the mechanism of the competing fragmentations and of the structures of the ions involved. The correlation of substituent effects with ionization potential and appearance potential measurements and with Δ(A.P. – I.P.) values suggests that the fragmentation of meta-substituted acetanilides proceeds through an excited state.