Oxidative Coupling of CH-acid Compounds with p-Phenylenediamines. IV. Mass Spectrometric Investigations of 4-Substituted 1-Hydroxy-2-naphthoic-acid Derivatives.
Mass spectrometric fragmentations of 4-substituted 1-hydroxy-N-3′, 5′-(dimethoxy-carbonyl)phenyl-2-naphthalene carboxamides and derivatives of 1-hydroxy-2-naphthoic acid and 4-bromo-1-hydroxy-2-naphthoic acid have been determined. All compounds undergo a characteristic fragmentation. The most important primary process is amide cleavage and hydrogen rearrangement. The relation of the primary fragments which compete for the charge depends on the substituents of the active methylene group and of the amide. The mass spectra permit determination of structure, purity and stability of the substituted colour couplers.