Electrospray‐Ionization Mass Spectrometry. Part 2. Neighboring‐Group Participation in the Mass‐Spectral Decomposition of 4‐Hydroxycinnamoyl‐spermidines

Abstract

The three mono substituted N-[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines1-3 have been studied by positive-ion electrospray-ionization tandem mass spectrometry (ESI-MS/MS). Because of the neighboring-group participation, the MS/MS of [l + H]+ and [2 + HIf are essentially similar, while compound 3 can be easily distinguished from 1 and 2 because of the characteristic ions at m / z 218. However, with the source collisioninduced dissociation (source-CID) MS/MS technique, the compounds 1 and 2 can be unambiguously distinguished by the signal of the pyrrolidinium ion (m/z 72) from their daughter ion ( m / z 275). The source-CID MS/MS of the labeled compound N-(4 -aminobutyl)-N-(3-aminopropyl)-N-[3-(4-hydroxyphenyi)prop-2-en['SN]amide] (["N(4)]-2) provide more information on the decomposition mechanisms and proved the occurrence of a partial transamidation reaction 2 -1 during the measurement Introduction. -The remarkable increase in information on the biochemical properties of polyamines and the awareness that inhibition of the enzymes involved in their biochemical pathways leads to valuable pharmacological agents, making these compounds important tools for the organic chemists [2]. Although the sporadic identification of the derivatives formed from the reaction of amines and 3-(4-hydroxyphenyl)prop-2-enoic acid ( = 4-hydroxycinnamic acid) in various plants has been reported for many years, it is only recently that the widespread nature and potential significance of these amides has been recognized [3] [4]. Since polyamine derivatives often appear as inseparable mixtures of minute amounts, electrospray-ionization mass spectrometry (ESI-MS) is generally used to investigate this class of compounds, especially due to the possibility of the on-line coupling with a HPLC system [5-71. To fully benefit from the potential of tandem mass spectrometry, it is important to comprehend the fragmentation mechanism of compounds under investigation, when this technique is used. Furthermore, informations on the decomposition reactions can be achieved by the application of the source-CID MS/MS technique [8] [9]. Herein, a MS/MS of the compound is produced in the ion source, and the thus generated ions can be further investigated by usual MS/MS analysis. Recently, the synthesis of all seven (E)-N-[3-(4-hydroxyphenyl)prop-2-enoyI]spermidines has been accomplished [lo]. The aim of this investigation is the mass-spectral identification of these compounds (for the mass-spectral behavior of the corresponding N,N-bis-(4-hydroxycinnamoyl)spermidines, see [ 1 11).

Spermidine and Flavonoid Conjugates from Peanut (Arachis hypogaea) Flowers

“…Evaluation of the EIMS fragmentation pattern for 6 was considered in an effort to locate the acetyl unit, although literature reports indicate that transamidation may lead to ambiguous conclusions. For example, Bokern , Bigler , and Hu noted the occurrence of a transamidation (the Zip reaction) of the [M + H] + ions for dicoumaroylspermidine under MS conditions. Even so, the EIMS fragmentation pattern enabled a proposal for the location.…”

On-Line Coupling of High-Performance Liquid Chromatography to Atmospheric Pressure Chemical Ionization Mass Spectrometry (HPLC/APCI-MS and MS/MS). The Pollen Analysis ofHippeastrum x hortorum (Amaryllidaceae)

“…They could not be differentiated by MS/MS techniques, since their fragmetation patterns are nearly the same. This has been explained by the occurrence of transamidation (the Zip reaction), which takes place under mass-spectrometric conditions [16] [17]. This reaction can be used to explain the fragment ions from the CID-MS in Fig.…”

Polyamine-Vectored Iron Chelators: The Role of Charge

“…Treatment of 25 with ethanolic HCl, generated in situ from acetyl chloride, 83 16), the result of successive de-3-aminopropylations of 10, was synthesized as in Scheme 5. Diphenol 24 was selectively alkylated with the O-tosylate of N-(tert-butoxycarbonyl)-4-amino-1-butanol (33), 85 generating alkyl aryl ether 34 in 55% yield. Hydrolysis of ester 34 under alkaline conditions gave BOC acid 35 (63%).…”