Mass Spectral Fragmentation Patterns of N,N′-Alkylidene and N,N′-Arylidene Bisamides

Abstract

The electron impact mass spectra of several gem-bisamides are studied. The dominant peaks in the spectra of alkylidene and arylidene bisalkylamides are formed by the cleavage of the C—N bond of the amido group with charge retention on the nitrogen atom. This fragmentation, followed by the loss of a neutral molecule, leads to characteristic immonium ions as the base peaks. In contrast, alkylidene and arylidene bisarylamides undergo cleavage of the C—N bond with charge retention on the carbon atom, leading to the benzoyl ion C6H5CO+ as the dominant peak. © 1997 John Wiley & Sons, Ltd.