178. Electrospray-ionization mass spectrometry part III: Acid-catalyzed isomerization of N,N′-bis[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines by the Zip reaction

Article abstract of DOI:10.1002/hlca.19960790810

The electrospray tandem mass spectra (ESI-MS/MS) of the three N,N′-bis[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines 1-3 displayed the same fragment-ion signals. These isomers could not be differentiated by ESI-MS/MS, since their fragmentation patterns are similar. (E,E)-N-(3-[ ¹⁵N]Aminopropyl)-3,3′-bis(4-hydroxyphenyl)-N,N′-(butane- 1,4-diyl)bis[prop-2-enamide] ([¹⁵N(1)]-1) was synthesized in order to get further information about the fragmentation mechanisms. The comparison of the ESI-MS/MS of 1 and [¹⁵N(1)]-1 revealed a transamidation, the Zip reaction, under mass-spectral conditions of the [1 + H]⁺ ions. Because of this reaction, the three isomers 1-3 could not be distinguished.