The fragmentations of substituted cinnamic acids after electron impact

Schaldach, Bernd; Grützmacher, Hans‐Friedrich

doi:10.1002/oms.1210150404

Cited by 34 publications

(18 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data strongly suggested that the ortho -isomer underwent a facile chlorine radical elimination via cyclization similar to that reported by Ronayne et al [10]. In addition, Schaldach and Grützmacher reported that m - and p -chlorocinnamic acids were capable of undergoing the same chlorine elimination process as the ortho analog [8]. …”

Section: Introductionsupporting

confidence: 79%

“…The cis-trans isomerization of double bonds has been shown to be a facile process upon electron ionization [18]. The carbonyl oxygen of the ester is now positioned to assist in the elimination of the halogen from the 2-position of the phenyl ring through the formation of a transitory 2-ethoxy-benzopyrylium intermediate [8]. This mechanism is consistent with the fact that skeletal rearrangements are often assisted by the presence of highly unsaturated groups [18].…”

Section: Resultsmentioning

confidence: 64%

“…Examination revealed that a significant loss of chlorine occurred from the molecular ion ( m/z 384) of ethyl trans -3-(3,7,8-trichlorodibenzo- p -dioxin-2-yl)-propenoate, giving a fragment of m/z 349. A search of the literature showed that this type of fragmentation pattern had been previously reported for α,β-unsaturated esters of propenoic acids and nitriles [7], cinnamic acids [8], and α-phenylcinnamic acids [9]. The fragmentation occurred via a substituted benzopyrylium intermediate, whose relative abundance depended upon the position of halogen substitution on the phenyl ring.…”

Section: Introductionmentioning

confidence: 54%

“…Formation of this ion in EI-MS has been observed for cinnamic acid esters [15], α,β-unsaturated esters of propenoic acids and nitriles [7], cinnamic acids [8], methyl cinnamates [16], α-fluorocinnamates [17] and α-phenylcinnamic acids [9]. In this mechanism, the trans -olefin isomerizes to place the phenyl ring and ester function in a cis configuration [10].…”

Section: Resultsmentioning

confidence: 99%

“…Earlier studies focused solely on substituted esters or nitriles and maintained the olefin linkage [7]. Follow up studies expanded this motif in cinnamic acids, but again maintained the olefin and did not vary the acid or linker/spacer moiety [8, 9]. We subsequently expounded upon this theme and synthesized analogs incorporating a variety of linkers between the phenyl ring and ester, including alkane (with one or two carbon atoms), alkene, substituted alkene, and alkyne moieties.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Substituted 3‐phenylpropenoates and related analogs: electron ionization mass spectral fragmentation and density functional theory calculations

Wheelock¹,

Colvin²,

Sanborn³

et al. 2008

J. Mass Spectrom.

View full text Add to dashboard Cite

Analysis of ethyl 3-(2-chlorophenyl)-propenoate by electron ionization mass spectrometry showed the distinct loss of an ortho chlorine. To characterize the structural requisites for the observed mass fragmentation, a series of 30 halogen-substituted 3-phenylpropenoate-related structures were examined. All ester-containing alkene derivatives exhibited loss of the distinctive chlorine from the 2-position of the phenyl ring. Analogous derivatives with the halogen (chlorine or bromine) in the para position did not evidence selective halogen loss. Results demonstrated that substituted 3-phenylpropenoates and their analogs fragment via the formation of a previously reported benzopyrylium intermediate. To understand the correlation between the intramolecular radical substitution and the abundance and selectivity of the chlorine (or other halogen) displacement, density functional theory calculations were performed to determine the charge on the principal cation involved in the chlorine loss (in the ortho, meta and para positions), the charge for the neutral radical (non-cation), the excess alpha electron density on the relevant atom and the energy to form the cation from the neutral atom (ionization energy). Results showed that the selectivity and extent of halogen displacement correlated highly to the electrophilicity of the radical cation as well as the neutral radical. These data further support the proposed fragmentation mechanism involving intramolecular radical elimination.

show abstract

Section: Introductionsupporting

confidence: 79%

Section: Resultsmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Substituted 3‐phenylpropenoates and related analogs: electron ionization mass spectral fragmentation and density functional theory calculations

Wheelock¹,

Colvin²,

Sanborn³

et al. 2008

J. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

Mass Spectrometry and Gas‐Phase Ion Chemistry of Phenols

Kuck

2009

Patai's Chemistry of Functional Groups

View full text Add to dashboard Cite

Introduction Gaseous Radical Cations Derived from Phenols: Thermochemistry of Some Typical Species and Reactions Unimolecular Fragmentation Reactions of Phenol Radical Cations The Effect of the Hydroxyl Group on the Reversible Intramolecular Hydrogen Transfer in Ionized Phenols Ortho Effects in Substituted Phenols Secondary Fragmentation Reactions of Phenol Radical Cations Miscellaneous Fragmentations of Phenol Radical Cations Chemical Ionization Mass Spectrometry of Phenols Ionized Phenol and Cyclohexa‐1,3‐Dien‐5‐One ( ortho ‐Isophenol) Generated by Fragmentation of Precursor Ions Ion/Molecule Reactions of Phenols in the Gas Phase Gaseous Phenol Anions Miscellaneous Analytical Examples Mass Spectrometry of Calixarenes Phenolic Compounds as Maldi Matrices Acknowledgements

show abstract

Massenspektrometrische Untersuchungen an Derivaten der Phenylessigsäure, 1. Mitt.: Verlust ortho‐ständiger Substituenten aus Phenylacetamid‐Ionen

Lee

Mayer

Wiegrebe

et al. 1988

Archiv der Pharmazie

View full text Add to dashboard Cite

In den EIMS (70 eV) der ortho-substituierten Phenylacetamide 2 und 3 treten für X = Cl, Br, N0 2 starke Signale für den Verlust von X-Radikalen auf, der bei niedrigen Anregungsenergien zur dominierenden bzw. einzigen Reaktion der sehr intensitätsschwachen Molekülionen (< 0.1 %) wird. Die ortho-ständigen Reste H, CH 3 unf F werden nicht, OCH 3 und CN in nur geringem Maße abgespalten. Der Verlust von o-Cl, o-Br und o-N0 2 ist positionsspezifisch, Abspaltung von meta-und para-ständigem Cl ist nicht nachzuweisen. Zusätzliche Methoxy-Substitution (7-9) erleichtert die Abspaltung der ortho-Nitrogruppe. Die MI-und CAD-Spektren der (M-X*) + -Ionen werden untersucht. MS Investigations on Derivatives of Phenylacetic acid, I: Loss of orthoSubstituents from Ionized PhenylacetamidesThe molecular ions of the ortho-substituted phenylacetamides 2 and 3 lose the ortho-substituents Cl, Br, and N0 2 , giving rise to strong (M-X') + -signals in their 70 and 12 eV mass spectra. The ortho substituents H, CH 3 , F as well as meta-and para-Cl, however, are not eliminated, o-OCH 3 and o-CN to a minor extent only. Additional methoxy substitution favours the loss of the o-N0 2 -group. The MI-and CAD-spectra of the (M-X') + -ions from 2d-f and 3c-e are discussed.Im Rahmen unserer Untersuchungen an Indolizidin-Alkaloiden 2) stellte /. Weiss 3) mehrere Derivate (la-c) des N-(3,4-Dimethoxy-6-nitro-phenylacetyl)-pyrrolidins dar. H3COH 3 co-In den MS (Elektronenstoß-Ionisation, EI) dieser Verbindungen dominiert die Abspaltung der N0 2 -Gruppe aus M + ', obwohl in derart komplexen Molekülionen auch andere, energetisch scheinbar günstigere Fragmentierungen zu erwarten wären. So bildet das Ion (M-*N0 2 ) + stets den basepeak (70 eV) und trägt über 50 % zum Totalionenstrom bei; bei niedrigeren Anregungsenergien (nom. 10-12 eV) ist es das einzige Fragmention von Bedeutung (L 4 0 > 90 %). Dieser unerwartete Befund veranlaßte uns, das Verhalten der kernsubstituierten Phenylacetamide 2-9 im Massenspektrometer zu prüfen.

show abstract

The fragmentations of substituted cinnamic acids after electron impact

Cited by 34 publications

References 14 publications

Substituted 3‐phenylpropenoates and related analogs: electron ionization mass spectral fragmentation and density functional theory calculations

Substituted 3‐phenylpropenoates and related analogs: electron ionization mass spectral fragmentation and density functional theory calculations

Mass Spectrometry and Gas‐Phase Ion Chemistry of Phenols

Massenspektrometrische Untersuchungen an Derivaten der Phenylessigsäure, 1. Mitt.: Verlust ortho‐ständiger Substituenten aus Phenylacetamid‐Ionen

Contact Info

Product

Resources

About