Das unterschiedliche massenspektrometrische Fragmentierungsverhalten von Lysinmethylester und dessen N,N′-Diacetylderivat. 27. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen |
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Authors: | Felix Roessler Manfred Hesse |
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Abstract: | The Different Behaviour of Lysine Methyl Ester and its N,N′-Diacetyl Derivative under Electron Impact The base peak in the spectrum of lysine methyl ester is due to the fragment ion C5H10N (m/e 84), for which the cyclic structure g (Scheme 1) is deduced. During its formation from the [M-COOCH3]-ion an equilibration of both nitrogen atoms takes place (ion c , Scheme 1). The cyclic nature of ion m/e 84 is in agreement with the intensity of the corresponding ions in the spectra of homologues of lysine methyl ester (Fig. 1). Although in comparison with lysine methyl ester ( 1 ) N,N′-diacetyl-lysine methyl ester ( 7 ) shows the same general fragmentation pathway with formation of the ions [M-COOCH3] and [M-COOCH3-H2NCOCH3] (m/e 126), the exact fragmentation mechanism proves to the different. Two mechanisms are discussed for the formation of the ion m/e 126 from 7 (Schemes 2 and 3). The results are based on the spectra of labelled derivatives. |
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