Mass spectrometry and structures of ions of heterocyclic compounds activated by collision. 2. 2-Methylnitroindolizines

The principal pathways of the fragmentation of 2-methylnitroindolizines were investigated. The fragmentation and structures of the isomeric M-OH]⁺ and M-NO]⁺ ions formed in the fragmentation of these compounds were studied by the method of dissociative activation by collision (DAC). It was established that the stable M-OH]⁺ ions formed in the fragmentation of the 1- and 3-nitro isomers as a result of the ortho effect have different structures and that their DAC spectra can be used to determine the position of the nitro group in the molecule.See 1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1631–1635, December, 1988.