Mass spectrometer as a probe in the synthesis of 2-substituted benzimidazoles

The pyrolysis of N,N'-diacyl-1,2-benzenediamines leads to the formation of 2-substituted benzimidazoles. This new synthetic approach towards the synthesis of 2-substituted benzimidazoles is developed based on the electron impact studies of N,N'-diacyl-1,2-benzenediamines under 70 eV conditions, in which important fragment ions corresponding to 2-substituted benzimidazoles are observed. The mechanisms and ion-structures, proposed in the mass spectral study, are supported by high-resolution, B/E and B2/E linked-scan spectra and Collision Activated Decomposition (CAD)-B/E linked-scan spectra. © 1994.