2,5-Dialkyltetrahydrofurans, common components of the cuticular lipids of Lepidoptera 

Z. Naturforsch., 1998, 53c, 107-116 (1998) 

S. Schulz, George Beccaloni², Ritsuo Nishida³, Yves Roisin⁴, R. I. Vane-Wright², Jeremy N. McNeil⁵ 

²Department of Entomology, British Museum (Natural History), Cromwell Road, London SW7 5BD, United Kingdom 
³Pesticide Research Institute, Kyoto University, Kyoto, 606-01, Japan 
⁴Faculté des Sciences C. P. 160, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50, B-1050 Bruxelles, Belgium 
⁵Departément de Biologie, Université Laval, Quebec, P. Q., G1K 7P4, Canada 

Keywords: Lipids, Tetrahydrofurans, Cyclic Ethers, Lepidoptera, Cuticula 

In more than 50 lepidopteran species 2,5-dialkyltetrahydrofurans were identified as components of the cuticular lipids. The chain length of these compounds varies between C₂₅ and C₃₇ and both cis- and trans-compounds are present. In addition, previously unknown 2-alkyl-5-(1-hydroxyalkyl)tetrahydrofurans were found in some species. The identification procedure and synthesis of representative compounds are reported and the possible function of these molecules is discussed. 

Origin of the defensive secretion of the leaf beetle Chrysomela lapponica 

Tetrahedron 53, 9203-9212 (1997) 

S. Schulz, 

J. Gross, M. Hilker 
Freie Universität Berlin, Institut für Zoologie, Haderslebener Str. 9, D-12163 Berlin, Germany 

Keywords: Leaf beetles, glycosides, biosynthesis, diols, Betula, Salix, Leaf alcohols 

The larvae of the European leaf beetle Chrysomela lapponica use esters of isobutyric acid and (S)-2-methylbutyric acid as defensive secretion. The acids are formed by the larvae from amino acids, as could be shown by experiments with deuterium labelled compounds. The alcohols taken up from the foodplant are either directly used for ester formation, like (Z)-3-hexenol and 8-hydroxylinalool, or modified as 1-hydroxy-3-hexanone. This ketol is reduced to the corresponding 1,3-hexanediol prior to esterification. The cleavage of the respective glycosides or oxidation of fatty acids during feeding on the leaves leads to these alcohols. The ketols 1-hydroxy-3-hexanone and its isomer 6-hydroxy-3-hexanone have not been reported before from nature. 

The Chemistry of Spider Toxins and Spider Silk 

Angew. Chem. 109, 324-337 (1997) and Angew. Chem. Int. Ed. Engl. 36, 314-326 (1997) 

Stefan Schulz 

Keywords: acyl polyamines, lipids, natural products, pheromones, spider toxins 

A review on the constituents of spider silk and spider toxins. Emphasis is given on low molecular weight components as acylpolyamines occurring in the venom and lipids on the silk. The chemical ecology of spiders is described, especially the use of pheromones and allomones by them. 

Identification and Synthesis of Elymniafuran, a New Monoterpene from the Butterfly Elymnias thryallis

Liebigs Ann. Chem., 1996, 941-946 

Stefan Schulz*, Mirjam Steffensky, 

Yves Roisin 
Faculté des Sciences C. P. 160, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50, B-1050 Bruxelles, Belgium 

Key Words: Elymniafuran, Monoterpene, Grignard reaction, enantioselective, Butterfly, Semiochemicals 

The main constituent of the scent gland secretion of the tropical butterfly Elymnias thryallis (Lepidoptera: Satyridae) could be identified to be (S)-2-methyl-1-(4-methyl-2-furyl)-3-buten-2-ol (elymniafuran). It is accompanied by small amou nts of (E)- and (Z)-4-methyl-(2-methyl-1,3-butadienyl)-furan as well as the spiroacetal 3,9-dimethyl-1,6-dioxaspiro[4.5]dec-3-ene. The structural assignment of these new natural products as well as the synthesis and enantiomeric separation by chiral gas chromatography are described. 

The Pheromone System of the male Danaine Butterfly, Idea leuconoe

Bioorg. Med, Chem. 1996, 4, 341-349 

S. Schulz, 

R. Nishida 
Pesticide Research Institute, Kyoto University, Kyoto, 606-01, Japan 

Keywords: pheromones, Danainae, lipids, Idea, hairpencil 

Male Idea leuconoe butterflies release a complex mixture of volatiles from their pheromone glands (hairpencils) during courtship. The pheromone components geranyl methyl thioether, viridifloric b-lactone, and 6-hydroxy-4-dodecanolide have been synthesized for the first time. Therefore the structural assignment of these new natural products could be proved. Related 7-hydroxy-5-alkanolides are also present in the extract. The volatiles are embedded in a lipidic matrix with more than 150 components. This matrix consists of alkanes, alkenes, 2,5-dialkyltetrahydrofurans, secondary alkanols and alkenols as well as alkanones and alkenones. Several regioisomers of the oxidized hydrocarbons occur. The elucidation of double bond positions has been performed by MS using DMDS adducts. 

New Lipids From Spiders and Insects

GIT 1996, 114-115, and Bioforum, 1996,  Article in german. 

S. Schulz 

The silk of spiders belonging to the genera Linyphiidae and Araneae (Nephila clavipes) contains unusual long chain, methyl branched, methyl ethers with chain length between 25 and 40, accompanied by alkanes, fatty acids and wax type esters. The ethers can be fully characterized by micro derivatization techniques. The derivatized as well as crude extracts are needed for GC-MS analysis to clarify the number and position of the methyl branches. On the cuticle of the butterflies unusual 2,5-dialkyltetrahydrofurans can be found, sometimes in high concentrations. 

Identification of a Sex Pheromone from a Spider

Science 1993, 260, 1635-1637 

S. Schulz, 

S. Toft 
Biologisk Institut, Afdeling for Zoologi, Universitetsparken, Bygning 135, DK-8000 Århus C, Denmark 

The compounds (R)-3-hydroxybutyric acid and its self-condensation product, (R)-3-[(R)-3-hydroxybutyryloxy]-butyric acid, have been identified as the first pheromone from a spider. These sex pheromones elicit web reduction behavior by males of Linyphia triangularis (Clerck) on the webs of unmated adult females. 

Absolute configuration and synthesis of 2-hydroxy-2-(1-hydroxyethyl)-3-methyl-g-butyrolactone, a presumed pheromone of ithomiine butterflies

Liebigs Ann. Chem. 1992, 829-834 

S. Schulz 

Key Words: pheromone / Ithomiinae / Ithomiolide / keto lactone / butterflies 

2-Hydroxy-2-(1-hydroxyethyl)-3-methyl-g-butyrolactone is a constituent of scent glands of male ithomiine butterflies. All diastereomers and the respective (3R)-enantiomers were synthesized starting from rac- or (3S)-3-methyl- g-butyrolactone. Their relative configurations were determined by difference-NOE-NMR spectroscopy or by X-ray diffraction analysis. The absolute configuration of the natural product was determined by chiral gas chromatography of the respective dioxolane derivatives. The natural lactone could be shown to be (2S,3R,1'S)-2-Hydroxy-2-(1-hydroxyethyl)-3-methyl-g-butyrolactone (Ithomiolide A). In addition, the corresponding ketone, (2S,3R)-2-acetyl-2-hydroxy-3-methyl-g-butyrolactone (Ithomiolide B) could be identified as a new natural product from Prittwitzia hymaenea.