Mass-spectrometric study of nitro derivatives of 2(4)-azafluorenes and 2(4)-azafluorenones

The dissociative ionization of 13 nitro derivatives of 2(4)-azafluorenes and 2(4)-azafluorenones was investigated. The introduction of an electron-acceptor nitro group into the molecule markedly reduces the stability of the molecular ions and suppresses the fragmentation pathways that are characteristic for azafluorenes. Nitro-nitrite rearrangement proceeds more readily in nitro-substituted 4-azafluorenes than in nitro-substituted 2-azafluorenes. A characteristic feature of the fragmentation of azafluorenes that do not contain nitro and methyl groups in a vicinal orientation is elimination of a OH particle by the molecular ions. It was established by deuterium labeling that in this case the formation of an [M — OH]⁺ ion is due to the presence of a methylene group attached to the C₉ atom in the molecule.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 941–947, July, 1981.