Three Hydrogens Rearrangement of 7-Piperazine-8-N-Quinolone

Characteristic fragment ions of 7-piperazine-8-N-quinolones as pipemidic acid, enoxacin, IMB-86001 in mass spectrometry were discussed. The results show that the spectra M-42, M-44, M-68, M-86 and m/z 56 are the common characteristic fragment ions in three compounds. The M-68 fragment ion probably results from a rearrangement of three hydrogens.