Structural and synthetic studies in chemical entomology
Structural and synthetic studies in chemical entomology
The alarm pheromones of the Ponerine ant Odontomachus troglodytes were found to be an homologous series of 2,6-dimethyi-a-n-aiicyiprazinesz the syntheses of these and 2,5-dimethyl-3-n-alkylprazines and 2,3-dimethyl-5-n-alkylpyrazines are described. The natural products were identified by solid sample gas chromatography, of whole ant heads, linked with mass spectrometry. Their structures were confirmed by spectral and chromatographic comparisons with synthetic samples. The major components were found to be 2,6-dimethyl3-n-butylpyrazine and n-pentylpyrazine with ethylpyrazine and n-hexylpyrazine present as minor components. Caste specific behavioural differences were found between males and workers in response to gland equivalent quantites of the synthetic pheromones. The passive males retreated from the alkylprazines, whereas the workers were attracted to and attacked the pheromone source. The multicomponent sex pheromone system of the Pine Beauty Moth, Panolis flammea, was identified. A variety of techniques including aeration,-so-Wd she gas chromatography and combined gas chromatography-mass spectrometry of solvent extracts of female abdomen tips were used in this study. The components were identified as three mono-unsaturated alkenyl acetates; 9-tetradecenyl acetate, 11-hexadecenyl acetate and 11-tetradecenyl acetate present in the female solvent extract in an approximate ratio of 100:20:1. Unambiguous identification of the natural products was obtained by the technique of methoxymercuration-demercuration with subsequent analysis of the methoxylated derivatives by gas chromatography-mass spectrometry. An initial study of the biological activity of synthetic samples of the (Z)isomers of the proposed natural products showed activity in the field. The Oak Leaf Roller Moth, Tortrix viridana, was also studied mainly by the technique of solid sample gas chromatography and the use of abstractor post loops. Sex specific components could not, however, be identified. The synthesis of three alkenyl acetates, (Z)-ll-tridecenyl acetate, (E)11-tridecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate are described. An approach to the synthesis of the sex pheromone mimic of the American cockroach, Periplaneta americana, germacrene-D is presented. The proposed synthesis involves the formation of the ten-membered ring via a Grob type fragmentation. The synthesis of the fragmentation precursor and preliminary investigations of fragmentation reactions are described. The analysis of a sample of germacrene-D from the cortex oil of Dendroporattrifidus with the spectral data is presented.
University of Southampton
1981
Speed, William
(1981)
Structural and synthetic studies in chemical entomology.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The alarm pheromones of the Ponerine ant Odontomachus troglodytes were found to be an homologous series of 2,6-dimethyi-a-n-aiicyiprazinesz the syntheses of these and 2,5-dimethyl-3-n-alkylprazines and 2,3-dimethyl-5-n-alkylpyrazines are described. The natural products were identified by solid sample gas chromatography, of whole ant heads, linked with mass spectrometry. Their structures were confirmed by spectral and chromatographic comparisons with synthetic samples. The major components were found to be 2,6-dimethyl3-n-butylpyrazine and n-pentylpyrazine with ethylpyrazine and n-hexylpyrazine present as minor components. Caste specific behavioural differences were found between males and workers in response to gland equivalent quantites of the synthetic pheromones. The passive males retreated from the alkylprazines, whereas the workers were attracted to and attacked the pheromone source. The multicomponent sex pheromone system of the Pine Beauty Moth, Panolis flammea, was identified. A variety of techniques including aeration,-so-Wd she gas chromatography and combined gas chromatography-mass spectrometry of solvent extracts of female abdomen tips were used in this study. The components were identified as three mono-unsaturated alkenyl acetates; 9-tetradecenyl acetate, 11-hexadecenyl acetate and 11-tetradecenyl acetate present in the female solvent extract in an approximate ratio of 100:20:1. Unambiguous identification of the natural products was obtained by the technique of methoxymercuration-demercuration with subsequent analysis of the methoxylated derivatives by gas chromatography-mass spectrometry. An initial study of the biological activity of synthetic samples of the (Z)isomers of the proposed natural products showed activity in the field. The Oak Leaf Roller Moth, Tortrix viridana, was also studied mainly by the technique of solid sample gas chromatography and the use of abstractor post loops. Sex specific components could not, however, be identified. The synthesis of three alkenyl acetates, (Z)-ll-tridecenyl acetate, (E)11-tridecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate are described. An approach to the synthesis of the sex pheromone mimic of the American cockroach, Periplaneta americana, germacrene-D is presented. The proposed synthesis involves the formation of the ten-membered ring via a Grob type fragmentation. The synthesis of the fragmentation precursor and preliminary investigations of fragmentation reactions are described. The analysis of a sample of germacrene-D from the cortex oil of Dendroporattrifidus with the spectral data is presented.
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Published date: 1981
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Local EPrints ID: 459214
URI: http://eprints.soton.ac.uk/id/eprint/459214
PURE UUID: ddfccb19-45ed-45a2-a56a-9e5b7683d3ba
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Date deposited: 04 Jul 2022 17:06
Last modified: 04 Jul 2022 17:06
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Author:
William Speed
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