Mass Spectra of Ketones

Sharkey, A.G.; Shultz, J.L.; Friedel, R. A.

doi:10.1021/ac60114a003

Cited by 124 publications

(32 citation statements)

References 18 publications

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“…A major pair of fragments formed during breakdown of a ketone in the mass spectrometer arises from homolytic fissions on either side of the carbonyl group. The identification of these a-cleavage peaks thus reveals the position of the carbonyl group(s) (2,25,32,43). An examination of the mass spectra of the three ketone peaks indicates that the C27 secondary alcohol in Foma is predominantly heptacosan-9-ol (m/e = 141 plus 281).…”

Section: ! Lipid Class Composition Of Spike Waxesmentioning

confidence: 98%

Composition of epicuticular waxes on barley spikes

Wettstein-Knowles

Netting

1976

Carlsberg Res. Commun.

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Hydrocarbons, alkan-l-ol and alkan-2-ol containing esters, 13-diketones, aldehydes, primary alcohols, hydroxy-13-diketones, free fatty acids and sometimes secondary alcohols are major lipid classes of epicuticular waxes on the spikes of the three wild type barley varieties Bonus, Foma and Carlsberg-ll and many of the 40 eceriferum (cer) mutants examined. Division of the spikes into two parts, the awns and the spike minus awns, before wax isolation reveals that (i) 13-diketones, hydroxy-13-diketones and esterified alkan-2-ols occur only on the spike minus awns, (ii) secondary alcohols are present only on the awns of Foma and its mutants and (iii) the other lipid classes are found on both parts of the spike. The chain length distributions of the lipid classes common to both parts of the spike are in some cases similar and in others different.

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Section: ! Lipid Class Composition Of Spike Waxesmentioning

confidence: 98%

Composition of epicuticular waxes on barley spikes

Wettstein-Knowles

Netting

1976

Carlsberg Res. Commun.

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“…The identification was confirmed with available authentic compounds, wherever possible. Identification of secondary alcohols and long-chain ketones from pollenkitt was based on their characteristic MS [16] [17] [39], and for the alcohols also on the spectra of their TMS derivatives [14]. To obtain TMS derivatives, the extracts of R. bulbosus were combined, evaporated to dryness, redissolved in CH 2 Cl 2 (1 ml), treated with 2,2,2-trifluoro-N-methyl-N-(trimethylsilyl)acetamide (0.25 ml) at 608 for 1 h, and directly analyzed by GC/MS.…”

Section: Experimental Partmentioning

confidence: 99%

“…The presence of these ions, and the absence of ions suggesting other position of the C¼O group, allowed us to assign the structure of the three methyl ketones [16]. Two 6,8-diketones from C. rapunculoides were unequivocally identified based on the presence of diagnostic ion peaks at m/z 43, 85, and 100, together with Thus, the pollenkitt lipids show high species specificity in the two analyzed species, similar to plant epicuticular lipids; thus, they may provide any pollinators with reliable information on pollen identity.…”

mentioning

confidence: 99%

Can Pollen Headspace Volatiles and Pollenkitt Lipids Serve as Reliable Chemical Cues for Bee Pollinators?

Piskorski

Kroder

Dorn

2011

Chemistry & Biodiversity

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Chemical analysis of putative contact chemical cues for pollinators from pollen of two plant species, Ranunculus bulbosus (Ranunculaceae) and Campanula rapunculoides (Campanulaceae), showed high consistency in the qualitative and quantitative composition of pollenkitt surface lipids in all samples analyzed per species. The pollenkitt lipids of R. bulbosus included an aldehyde, fatty acid amides, saturated and unsaturated hydrocarbons, and secondary alcohols; the lipids of C. rapunculoides consisted of an aldehyde, monoketones, and β-diketones. In marked contrast, the pollen headspace volatiles showed a wide qualitative and quantitative variability among all samples per species, whereby the variability was more pronounced in R. bulbosus. Hence, the highly species-specific pollenkitt lipids may provide pollinators with more reliable information on pollen identity.

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“…16 Neither the available ethyl alkyP6 nor phenyl alkyl: ketones show loss of C2H4. Thus, these classes of ketones show no characteristic behavior pointing to a cyclobutanol intermediate.…”

Section: Hzmentioning

confidence: 99%

Reactions of aliphatic aldehydes under electron‐impact

Meyerson¹,

Fenselau

Young

et al. 1970

Org. Mass Spectrom.

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The mass spectra of hexanal, heptanal and nonanal variously labeled with deuterium confirm γ‐hydrogen migration and β cleavage as the mechanism leading to [C2H4O]+˙ and [M  C2H4O]+˙, although the data on the latter are complicated by contributions from other, related paths. In addition, they show that three other major primary decomposition products, [M  C2H4]+˙, [M  H2O]+˙ and [C3H5O]+, all arise in large part by processes involving γ‐hydrogen migration to the oxygen atom. The ethylene lost to yield the first of these products consists of the α and β methylene groups. The loss of ethylene most likely occurs by way of a cyclobutanol intermediate, which, via alternative reaction paths, may well contribute to the yields of the other two products as well. These findings further extend the range of parallelism between photochemical and electron‐impact‐induced reactions.

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Mass Spectra of Ketones

Cited by 124 publications

References 18 publications

Composition of epicuticular waxes on barley spikes

Composition of epicuticular waxes on barley spikes

Can Pollen Headspace Volatiles and Pollenkitt Lipids Serve as Reliable Chemical Cues for Bee Pollinators?

Reactions of aliphatic aldehydes under electron‐impact

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