Mass Spectra of Some Di- and Triazaindenes

The mass spectra of imidazo[l,2-a]pyridine (I), imidazo[ 1,5-a]pyridine (11), imidazo[l12-a]pyrimidine (111), and various methyl derivatives are reported and analyzed. The parent compounds lose HCN and CzHzN. In the methyl derivatives, analogous fragmentations occur. In addition, the loss of a hydrogen atom from the methyl group results in possible ring-expanded products which subsequently lose HCN as well as C4H4. The major fragmentations of the parent ion radicals are in agreement with the ion-radical bond orders