Studies in organic mass spectrometry—VI. The fragmentation of enol derivatives of acyclic β‐diketones

Vandewalle, M.; Schamp, N.; Francque, M.

doi:10.1002/oms.1210020903

Cited by 9 publications

(2 citation statements)

References 8 publications

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“…Experimental Section 2-Methyl-5,7-di-tert-butylbenzoxazole (6). A solution of 0.445 g (5.00 mmol) of alanine and 2.95 g (5.00 mmol) of tetraethylammonium hydroxide, 25% aqueous solution, was concentrated at reduced pressure until about 180 mg of water remained.…”

Section: Resultsmentioning

confidence: 99%

A new reaction of amino acids: conversion to benzoxazoles

Zwan¹,

Hartner²,

Reamer³

et al. 1978

J. Org. Chem.

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Section: Resultsmentioning

confidence: 99%

A new reaction of amino acids: conversion to benzoxazoles

Zwan¹,

Hartner²,

Reamer³

et al. 1978

J. Org. Chem.

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“…Moreover, enaminones and their derivatives have shown good biological activities, including anticonvulsant, antimalarial, anti‐inflammatory, antifungal as well as antibacterial activity 31–34. Mass spectrometry has been used for the identification and the structural characterization of enaminones since 1960s by electron ionization (EI), electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) 35–38. However, the previous studies mainly focused on the determination of enaminones by liquid chromatography/mass spectrometry (LC/MS) and the fragmentation pattern of enaminones in EI‐MS.…”

Section: Introductionmentioning

confidence: 99%

An experimental and computational investigation on the fragmentation behavior of enaminones in electrospray ionization mass spectrometry

Guo

Wan

et al. 2010

J. Mass Spectrom.

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The dissociation pathways of protonated enaminones with different substituents were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in positive ion mode. In mass spectrometry of the enaminones, ArCOCHCHN(CH(3) )(2) , the proton transfers from the thermodynamically favored site at the carbonyl oxygen to the dissociative protonation site at ipso-position of the phenyl ring or the double bond carbon atom adjacent to the carbonyl leading to the loss of a benzene or elimination of C(4) H(9) N, respectively. And the hydrogendeuterium (H/D) exchange between the added proton and the proton of the phenyl ring via a 1,4-H shift followed by hydrogen ring-walk was witnessed by the D-labeling experiments. The elemental compositions of all the ions were confirmed by ultrahigh resolution Fourier transform ion cyclotron resonance tandem mass spectrometry (FTICR-MS/MS). The enaminones studied here were para-monosubstituted on the phenyl ring and the electron-donating groups were in favor of losing the benzene, whereas the electron-attracting groups strongly favored the competing proton transfer reaction leading to the loss of C(4) H(9) N to form a benzoyl cation, Ar-CO(+) . The abundance ratios of the two competitive product ions were relatively well-correlated with the σ(p) (+) substituent constants. The mechanisms of these reactions were further investigated by density functional theory (DFT) calculations.

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The mass spectra of hydroxyl compounds

Cooks

1971

The Hydroxyl Group (1971)

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Studies in organic mass spectrometry—VI. The fragmentation of enol derivatives of acyclic β‐diketones

Cited by 9 publications

References 8 publications

A new reaction of amino acids: conversion to benzoxazoles

A new reaction of amino acids: conversion to benzoxazoles

An experimental and computational investigation on the fragmentation behavior of enaminones in electrospray ionization mass spectrometry

The mass spectra of hydroxyl compounds

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