- Sex pheromone components of the apple leafminer, Lyonetia prunifoliella
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Three methylated hydrocarbons, 10,14-dimethyloctadec-1-ene (10Me14Me-1-ene-18Hy = 5Me9Me-17-ene-18Hy), 5,9-dimethyloctadecane (5Me9Me-18Hy), and 5,9-dimethylheptadecane (5Me9Me-17Hy), are synergistic sex pheromone components of the leafminer Lyonetia prunifoliella. Compounds extracted from female pheromone glands were identified by coupled gas chrormatographic-electroantennographic detection (GC-EAD), and one compound, 10Me14Me-1-ene-18Hy, also by coupled GC-mass spectrometry. In field trapping experiments, 10Me14Me-1-ene-18Hy, 5Me9Me18Hy, and 5Me9Me-17Hy singly were unattractive to males but in ternary combination attracted numerous male moths. Attractiveness of the three-component blend significantly exceeded that of two-component blends. No attraction of males to pheromone lures without 10Me14Me-1-ene-18Hy indicates that this compound is essential for pheromone communication of L. prunifoliella. Common C-5 and C-9 methyl branches in lyonetiid pheromone hydrocarbons suggest a common biosynthetic pathway; the presence of 5Me9Me-17Hy and 5Me9Me-18Hy in pheromone blends of L. prunifoliella and Leucoptera malifoliella provides evidence for phylogeny of lyonetiid chemical communication. Determination of the stereoisomeric composition is required to completely describe the pheromone blend of L. prunifoliella and to support the hypothesis of phylogenetically related sex pheromones.
- Gries, Regine,Gries, Gerhard,King, G. G. Skip,Maier, Chris T.
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- Do enzymes recognise remotely located stereocentres? Highly enantioselective Candida rugosa lipase-catalysed esterification of the 2- to 8-methyldecanoic acids
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Several racemic methyl decanoic acids have been synthesised and successfully resolved in esterification with 1-hexadecanol at aw=0.8 in cyclohexane using immobilised Candida rugosa lipase (CRL) as the catalyst. The enantiomeric ratios (E=2.8-68) obtained were surprisingly high even when the methyl group was as remotely located as in 8-methyldecanoic acid (E=25). Interestingly, the lipase shows enantiopreference for the S-enantiomer when the methyl group is located on even numbered carbons i.e. for the 2-,4-,6- and 8-methyldecanoic acids and to the R-enantiomer when the methyl group is located on uneven numbered carbons i.e. for the 3-,5- and 7-methyldecanoic acids.
- Hedenstroem, Erik,Nguyen, Ba-Vu,Silks III, Louis A.
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p. 835 - 844
(2007/10/03)
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- Exo- and endohormones. XVII: Synthesis of racemic 5,9-dimethyl-heptadecane, the sex pheromone for the leafminer moth Leucoptera scitella
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The paper describes two practical syntheses of 5,9-dimethyl-heptadecane, the sex pheromone of the leafminer moth Leucoptera scitella (Lepidoptera, Lyonetidae). The first route (Scheme 1) involves as key reaction the coupling of 2-methyl-hexyl magnesium bromide with 3-methyl-undecanal. The second route (Scheme 3) is based on the Schlosser-Fouquet coupling reaction of 2-decyl-magnesium bromide with 4-methyl-octyl bromide.
- Ciocan-Tarta, Ilie,Oprean, Ioan,Ghizdavu, Iustin,Pojar-Fenesan, Maria
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p. 215 - 219
(2007/10/03)
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