Mass Spectrometry of Imidazole-4(5)-carboxaldehyde and Some 1-Methyl and Nitro Derivatives

Article abstract of DOI:10.1002/oms.1210210810

The mass spectra of imidazole-4(5)-carboxaldehyde, its two 1-methyl derivatives, 4(5)-nitroimidazole, 5(4)-nitroimidazole-4(5)-carboxaldehyde and 1-methyl-5-nitroimidazole-4-carboxaldehyde are presented and discussed in comparison with those of other imidazole-carboxaldehydes and nitroimidazoles earlier reported.The imidazole-carboxaldehydes and their 1-methyl derivatives exhibit the characteristic fragmentation of aromatic aldehydes, and differences between the isomers can be observed.The nitroimidazoles show the fragmentation typical of aromatic nitrocompounds.In the o-nitroimidazole-carboxaldehydes, the typical losses of aldehydes do not occur, but primary ortho effects between the formyl and nitro groups give rise to important fragmentation routes.In their 1-methyl derivatives, the presence of the methyl group adjacent to the nitro group originates additional double and secondary ortho effects.For some of these transformations, fragmentation mechanisms are proposed.