Mass spectral studies of naphthoflavones

Guidugli, Federico; Kavka, J.; Garibay, M. E.; Santillán, Rosa; Joseph‐Nathan, Pedro

doi:10.1002/oms.1210220802

Cited by 6 publications

(8 citation statements)

References 16 publications

(4 reference statements)

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“…In compounds 4, 5 and 7, the search for parent ions by using a linked scan at constant B 2 /E showed metastable transitions for the sequence a → [a À CO] → [a À CO À CO] corresponding to peaks at m/z 200 → 172 → 144, in agreement with the sequences 120 → 92 → 64 and 170 → 142 → 114 observed in flavones 1 and naphthoflavones, 3 respectively. Furthermore, low-energy collision experiments using the GCQ Plus instrument suggest that these sequences would be simple competitive eliminations of methyl vs. CO is the one case, and of methyl vs. two CO molecules in the other case, as summarized in Table 2.…”

supporting

confidence: 73%

“…at m/z 302 → 301 → 273 → 245, as 3 The contribution of the pentacyclic species to m/z 301 (Scheme 5) seems to be small since its abundance in the spectrum of 7 is almost the same as that in 4 (Table 1). In any event, it is interesting to note that, for the unsubstituted b-naphthoflavone (11), the abundance of the [M À H] fragment 3 is nearly treble that of a-naphthoflavone (10).…”

mentioning

confidence: 90%

“…As observed in flavones, 1 monomethoxyflavones 1,2 and naphthoflavones, 3 methoxynaphthoflavones show the [M] Á ion as the base peak, thus facilitating the study of RDA reactions and other fragmentations by MS/MS methods.…”

mentioning

confidence: 99%

“…3,[17][18][19][20] Alternatively, when the B-ring bears two or three methoxyl groups located at C-3' and C-4' or at C-3', C-4' and C-5' (compounds 1, 2, 3 and 6), the ion abundance corresponding to the A-fragment drops to figures lower than 25 %, while the B-fragment is now significant, having an intensity comparable to that of the A-fragment. These data indicate that the methoxyl groups on the B-ring allow a better delocalization of the positive charge, thus facilitating its stabilization.…”

mentioning

confidence: 99%

“…Once these methoxynaphthoflavones had been shown to exhibit the classical cleavages of flavones, 1 monomethoxyflavones 1 and naphthoflavones, 3 we focused our attention on the [M À H] species which, in flavones as well as in naphthoflavones, has been shown to correspond to a subsstituted b-tropolone.…”

mentioning

confidence: 99%

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Mass spectral studies of methoxynaphthoflavones

Ardanaz

Guidugli

Catalán

et al. 1999

Rapid Commun. Mass Spectrom.

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The electron impact induced fragmentations of seven methoxynaphthoflavones have been studied with the aid of low- and high-resolution measurements, metastable decompositions and isotope labelling using carbon-13 atoms. The retro Diels-Alder cleavage of the methoxynaphthoflavones is strongly influenced by the substituent position providing in most cases intact A- and B-ring fragments. The intensity ratio of these ring fragments appears to be very sensitive to the charge distribution within the parent ion. Copyright -Copyright 1999 John Wiley & Sons, Ltd.

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supporting

confidence: 73%

mentioning

confidence: 90%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Mass spectral studies of methoxynaphthoflavones

Ardanaz

Guidugli

Catalán

et al. 1999

Rapid Commun. Mass Spectrom.

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Origin of the [M − H]⁺ ion in flavanone

Guidugli

Kakva

Santillán

et al. 1992

Org. Mass Spectrom.

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A comparison of the combination of fast‐atom bombardment with tandem mass spectrometry and of gas chromatography with mass spectrometry in the analysis of a mixture of kaempferol, kaempferide, luteolin and oleouropein

Baracco

Bertin

Gnocco

et al. 1995

Rapid Comm Mass Spectrometry

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Two different approaches, i.e. fast-atom bombardment tandem mass spectrometry and gas chromatography combined with mass spectrometry (GUMS) have been employed for the characterization of a mixture of biologically relevant polyphenols (kaempferide, kaempferol, luteolin and oleouropein). The best results have been achieved by the first approach which allows an easy structural identification of the different compounds, also in the presence of isomers. G U M S of the trimethylsilyl derivatives leads to a complex chromatogram due to the presence of derivatives exhibiting a different level of silylation; the only species related to oleouropein are due to pyrolysis products (silylated fragments of sugars) and there is no evidence for the related silylated aglycone.Polyphenol compounds are widely distributed in the plant kingdom'.' and can be divided into different classes such as phenolic acids and derivatives, coumarins, flavonols, anthocyans, tannins and so on. In particular, flavonoids show a wide range of biochemical and pharmacological effects3 and consequently the structural characterization of these compounds represents a topic of wide interest.For such reasons, many papers have appeared on the mass spectrometric behaviour of these compounds, as well as on the results achievable with different mass spectrometric approaches.A series of papers, due to Guidugli et al. ,4-7 describe in great detail the behaviour of flavones, naphthoflavones and flavanones. In the first of them, the electronimpact (EI) induced fragmentation pattern of flavone has been fully elucidated by means of accurate mass measurements, metastable ion studies and deuterium labelling experiments; a particular emphasis was devoted to the mechanism of the [M-HI+ ion formation in substituted flavones. In a further paper,5 the structure of the [M-HI' ion of dibenzo-b-tropolone was proved by means of extensive deuterium labelling and comparison of linked-scan spectra. In the case of naphthoflavones,' the CO loss and the retruDiels-Alder processes were found to be characteristic.While EI is highly effective for the structural characterization of flavone and its derivatives with non-highly polar substituents, it shows severe limitations in the case of flavonols and related plant phenolics, as well as for 0-and C-glycosides because of their low volatility and poor thermal stability. For such reasons their derivatization becomes essential before examination, and methylationx-15 and trimethylsilylation'6,'7 pro-* Author for correspondence.cedures have been proposed; using such approaches the analysis of flavonoid-containing complex mixtures by gas chromatography/mass spectrometry (GUMS) became possible."For the analysis of underivatized compounds, field desorption was first proposed," but with the introduction of the fast-atom bombardment (FAB)" technique, mass spectra of underivatized compounds were more easily obtained. The first paper on FAB of a series of underivatized flavonol aglycones and glycosides is due to de Koster et ~1 .~' These authors focused ...

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Mass spectral studies of naphthoflavones

Cited by 6 publications

References 16 publications

Mass spectral studies of methoxynaphthoflavones

Mass spectral studies of methoxynaphthoflavones

Origin of the [M − H]⁺ ion in flavanone

A comparison of the combination of fast‐atom bombardment with tandem mass spectrometry and of gas chromatography with mass spectrometry in the analysis of a mixture of kaempferol, kaempferide, luteolin and oleouropein

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Mass spectral studies of naphthoflavones

Cited by 6 publications

References 16 publications

Mass spectral studies of methoxynaphthoflavones

Mass spectral studies of methoxynaphthoflavones

Origin of the [M − H]+ ion in flavanone

A comparison of the combination of fast‐atom bombardment with tandem mass spectrometry and of gas chromatography with mass spectrometry in the analysis of a mixture of kaempferol, kaempferide, luteolin and oleouropein

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Origin of the [M − H]⁺ ion in flavanone