Organic reactions on alumina

Scots pine has been shown to produce a volatile bouquet that attracts egg parasitoids in response to oviposition of the herbivorous sawfly Diprion pini. Previous analyses of headspace volatiles of oviposition-induced pine twigs revealed only quantitative changes; in particular, the sesquiterpene (E)-b-farnesene was emitted in significantly higher quantities by oviposition-induced pine. Here we investigated whether (E)-b-farnesene attracted the egg parasitoid Chrysonotomyia ruforum. We tested the behavioural response of C. ruforum females to different concentrations of (E)-b-farnesene. Egg parasitoids did not respond to this sesquiterpene at either concentration tested. However, they did respond significantly to (E)-b-farnesene when this compound was offered in combination with the volatile blend emitted from pine twigs without eggs. This response was dependent on the applied concentration of (E)-b-farnesene. Further bioassays with other components [(E)-b-caryophyllene, d-cadinene] of the odour blend of pine were conducted in combination with the volatile blend from egg-free pine as background odour. None of the compounds tested against the background of odour from an egg-free pine twig were attractive to the egg parasitoid. These results suggest that the egg parasitoids responded specifically to (E)-b-farnesene, but only when this compound was experienced in the right context, i.e. when contrasted with a background odour of non-oviposition-induced pine volatiles.

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The significance of background odour for an egg parasitoid to detect plants with host eggs.

Citronellal as key compound in organic synthesis

For a reaction to proceed it is necessary that the reacting species: molecules, ions, etc., can enter intimate contact. It is, therefore, a natural tendency to carry out chemical reactions in homog...

Phase Transfer Catalysis

In a four-armed airflow olfactometerTrichogramma evanescens Westwood females were attracted by a volatile substance(s) released by virgin females of the great cabbage white butterfly,Pieris brassicae L. Males or recently mated females did not cause attraction. Furthermore,T. evanescens was also attracted by volatiles released by calling virgin cabbage moths,Mamestra brassicae L. However, the parasites did not respond to (Z)-11-hex-adecenylacetate (the main component of the sex pheromone ofM. brassicae), a crude hexane extract of the sex pheromone gland, or to males or recently mated females.

Kairomones for the egg parasiteTrichogramma evanescens Westwood

Synthesis and rearrangement of 13-thiaprostanoids

Baker's yeast mediated synthesis of (5SR, 9S)-5,9-dimethyl-heptadecane and (5SR, 9S)-5,9-dimethyl pentadecane; the main sex-pheromone components of Leucoptera scitella and Perileucoptera coffeella enriched in 9S-isomers

L. Novak

Papers

Synthesis and rearrangement of 13-thiaprostanoids

Baker's yeast mediated synthesis of (5SR, 9S)-5,9-dimethyl-heptadecane and (5SR, 9S)-5,9-dimethyl pentadecane; the main sex-pheromone components of Leucoptera scitella and Perileucoptera coffeella enriched in 9S-isomers

Sex pheromone of the cabbage armyworm, mamestra brassicae: isolation, identification and stereocontrolled synthesis

Novel molecular rearrangements of 4 hydroxy 2 cyclopentenones

Rearrangement of Allyl Aryl Ethers I. Reaction of hydroquinone with conjugated Dien-ols and Trien-ol