Oxidation of hydroxymethylpyrazines and hydroxylated phenyl compounds in a gas chromatography inlet

Bohman, Björn; Flematti, Gavin R.

doi:10.1039/c4ay02958e

Cited by 3 publications

(2 citation statements)

References 41 publications

(45 reference statements)

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“…We believe that hydroxymethylpyrazines are more abundant in natural systems than is currently known and suggest that the lack of knowledge about their fragmentation patterns results in them passing unidentified in many systems. With the prevalence of pyrazines as flavouring agents in foods, as bacterial volatiles and with their growing recognition as insect semiochemicals, the results from our investigation of the EIMS fragmentations of hydroxymethyl‐substituted pyrazines presented here, together with previous reported GC behaviour, should aid other scientists in efforts to identify this important class of natural products using GC–MS techniques.…”

Section: Resultsmentioning

confidence: 99%

Identification of hydroxymethylpyrazines using mass spectrometry

2015

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Pyrazines are well-known natural products that are present in bacterial odours and food flavouring agents and are used as insect pheromones. Recently, a number of hydroxymethylpyrazines have been identified as thynnine wasp pheromones and orchid semiochemicals that are essential for pollination in sexually deceptive plants. These compounds are present in low amounts in complex blends, making GC-MS (including high-resolution techniques) the method of choice for their structure elucidation. We report the EI mass spectra for 14 representative compounds and have found that based on characteristic fragmentations, it is possible to distinguish between different positional isomers of hydroxymethylpyrazines. The presence or absence of either [M - 17] , [M - 18] or [M - 19] fragment species provides characteristic information to allow the distinction between the different isomers. Considering the importance of pyrazines as a group of bioactive natural products, and the recent findings of biological activity for hydroxymethylpyrazines, our results presented here will aid the identification of these compounds in other biological systems. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Identification of hydroxymethylpyrazines using mass spectrometry

2015

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“…Compound 4 was identified by co-injection as 4-(2-hydroxyethyl)-2-methoxyphenol (homovanillyl alcohol). Compound 7 was identified as 3,5,6-trimethylpyrazine-2-carbaldehyde, which may in fact be an artefact from the analysis, formed in the GC-inlet by oxidation [49] and was therefore not included in any analyses. Compound 6 was tentatively identified as a C21-alkene (double bond position not confirmed).…”

Section: Compounds That Differ Between Ecotypesmentioning

confidence: 99%

Three Chemically Distinct Floral Ecotypes in Drakaea livida, an Orchid Pollinated by Sexual Deception of Thynnine Wasps

Weinstein

Bohman

Flematti

et al. 2022

Plants

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Sexually deceptive orchids are unusual among plants in that closely related species typically attract different pollinator species using contrasting blends of floral volatiles. Therefore, intraspecific variation in pollinator attraction may also be underpinned by differences in floral volatiles. Here, we tested for the presence of floral ecotypes in the sexually deceptive orchid Drakaea livida and investigated if the geographic range of floral ecotypes corresponded to variation in pollinator availability. Pollinator choice trials revealed the presence of three floral ecotypes within D. livida that each attracts a different species of thynnine wasp as a pollinator. Surveys of pollinator distribution revealed that the distribution of one of the ecotypes was strongly correlated with that of its pollinator, while another pollinator species was present throughout the range of all three ecotypes, demonstrating that pollinator availability does not always correlate with ecotype distribution. Floral ecotypes differed in chemical volatile composition, with a high degree of separation evident in principal coordinate analysis. Some compounds that differed between ecotypes, including pyrazines and (methylthio)phenols, are known to be electrophysiologically active in thynnine wasp antennae. Based on differences in pollinator response and floral volatile profile, the ecotypes represent distinct entities and should be treated as such in conservation management.

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