Mass spectrometry of N‐substituted amino acids and their derivatives: Correlation of the abundances of the M^+. and selected fragment ions of metamers

Abstract

The mass spectral fragmentations of nineteen new metameric N-(E)-stilbenyloxyalkylcarboayl-[or (E)4'chlorostilbenyloxyalkylcarbonyl)~ -substituted amino acids and their metameric methyl esters and hydrazides were investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transition measurements. The correlation between the intensities of M+' and the selected fragment ions of these compounds is discussed. The data obtained create the basis for distinguishing metamers.

Electron ionization induced mass spectral study of new metameric N‐(E)‐stilbenyloxyalkylpiperidines, N‐(E)‐stilbenyloxyalkyl‐4‐methylpiperidines and N‐(E)‐stilbenyloxyalkylmorpholines

“…On the basis of low-resolution EI mass spectra, as well as collision-induced dissociation (CID) B/E linked-scan spectra and exact mass determinations (Tables 1-3 It should be pointed out that only the fragmentation of the molecular ions a of 1-21 has been confirmed by B/E linked-scan spectra, and the MS/MS transitions observed in these experiments are labeled with asterisks in Schemes 1 and 2. It is possible that the stilbenyloxyalkyl substitutents of the molecular ions of 1-21 have a tricyclic dihydrophenantrenoxyalkyl structure, as postulated by us previously when studying the fragmentation of the molecular ions of the 2-and 4-(E)-stilbenyloxyalkylthiouracils, 11 N-(E)-stilbenyloxyalkylcarbonyl-substituted amino acids and their metameric methyl esters and hydrazides, 13 as well as N-(E)-stilbenyloxyalkylcarbonyl-substituted hydrazones of arylaldehydes. 14 As can be seen from Scheme 1 and also from Tables 1 and 2, the principal fragmentations of the molecular ions of N-(E)-stilbenyloxyalkylpiperidines (1-7) and 4-methylpiperidines (8)(9)(10)(11)(12)(13)(14) are similar.…”

“…It is possible that the stilbenyloxyalkyl substitutents of the molecular ions of 1-21 have a tricyclic dihydrophenantrenoxyalkyl structure, as postulated by us previously when studying the fragmentation of the molecular ions of the 2-and 4-(E)-stilbenyloxyalkylthiouracils, 11 N-(E)-stilbenyloxyalkylcarbonyl-substituted amino acids and their metameric methyl esters and hydrazides, 13 as well as N-(E)-stilbenyloxyalkylcarbonyl-substituted hydrazones of arylaldehydes. 14 As can be seen from Scheme 1 and also from Tables 1 and 2, the principal fragmentations of the molecular ions of N-(E)-stilbenyloxyalkylpiperidines (1-7) and 4-methylpiperidines (8)(9)(10)(11)(12)(13)(14) are similar. The common features of the fragmentation of the molecular ions of 1-14 are simple cleavages of Csp 3 -O bonds in the alkoxy chain accompanied by migration, or retention of charge, i.e.…”

“…However, the EI fragmentation of their N-(E)-stilbenyloxyalkyl-substituted derivatives has not been reported. The purpose of this investigation was to elucidate the EI fragmentations of 21 new N-(E)-4 0 -stilbenyl-4-oxyalkylsubstituted derivatives of piperidine (1-7), 4-methylpiperidine (8)(9)(10)(11)(12)(13)(14) and morpholine (15)(16)(17)(18)(19)(20)(21), with two to five carbons in a straight alkyl chain ( Fig. 1).…”

“…1). This investigation was also undertaken to establish whether it is possible to differentiate the metameric N-(E)-stilbenyloxyalkyl-substituted piperidines (2,3,4,6,7) and N-methylpiperidines (8,9,10,12,13) on the basis of their EI mass spectra. Compounds 1-21 ( Fig.…”

Electron ionization mass spectrometry in the analysis of substituted stilbenethiols

“…8 The fragmentation of stilbene and its derivatives upon electron ionization has been the subject of several studies. [9][10][11][12][13] However, the fragmentation of stilbenethiols and their derivatives has not been reported to the best of our knowledge.…”