o‐Nitrobenzylidene compounds. I—Competitive ortho interactions in the mass spectra of n‐o‐nitrobenzylidene‐o‐substituted anilines

Abstract

The intense [M -17]+ ion, which is a characteristic feature of the mass spectra of N-a-nitrobenzylideneaniline and its simple derivatives, may be substantially reduced in intensity when the aniline-derived ring is also ortho substituted: the intensity is lowest when this ortho substituent has a nucleophilic character and can itself interact with the CH=N group. The ortho substituents examined are Br, CH,, OH, NHa, SH, SC6H4CH3@), C0,CH3 and COICIH5.