Otto Vostrowsky

Sidewall Functionalization of Carbon Nanotubes

The addition of nitrenes, nucleophilic carbenes, and radicals affords soluble, individual single-walled nanotubes (shown here is a carbene-functionalized adduct) by covalent sidewall functionalization. The characterization, a fundamental problem in nanotube chemistry, is simple to carry out.

A new pheromone of the silkworm moth Bombyx mori

The female silkmoth Bombyx mori L. emits a second pheromone component bombykal (E-10, Z-12-hexade-cadien-1-al) in addition to the well-known sexual attractant bombykol (E-10, Z-12-hexadecadien-1-ol). Bombykal stimulates its own specialized and highly sensitive olfactory cells of the male moth. Surprisingly, the aldehyde inhibits the release of the males wing-fluttering response to bombykol.

C60 Hexakisadducts with an Octahedral Addition Pattern − A New Structure Motif in Organic Chemistry

Hexakisadducts, with Th-symmetrical addition patterns, of C60 buckminsterfullerene can be obtained by means of cycloadditions, solid state reactions and nucleophilic cyclopropanations, including a variety of template and tether techniques. C60 — or a precursor adduct — serves as a core building block for elaboration into a pseudo-octahedral architecture; an aesthetically pleasing structure motif unique in organic chemistry. The fullerene core can be systematically embellished with one or more different types of addends, giving rise to the formation of uniform or mixed hexakisadducts, respectively. The regioselective exohedral chemistry of C60 may serve to provide soluble fullerene derivatives, lipofullerenes, dendrimers, charge-transfer systems, globular amphiphiles and compounds with interesting chemical, physical, biological and material properties.

Technique for injecting intact glands for analysis of sex pheromones of Lepidoptera by capillary gas chromatography : Reinvestigation of pheromone complex ofMamestra brassicae.

The structure elucidation of sex pheromones of Lepidoptera by a solid-sample injection technique in conjunction with capillary gas chromatography is described. The applicability of this method in GC and GC-MS modes was demonstrated by reanalyzing the sex attractants of females ofOstrinia nubilalis andBombyx mori. The pheromone complex ofMamestra brassicae was reinvestigated and (Z)-9-hexadecenyl acetate and (Z)-11-hexadecenol were found in addition to already known pheromone components of this species. By using the solid-sample injection, the exact site of pheromone release could be determined inM. brassicae.

Chemical composition and function of metapleural gland secretion of the ant,Crematogaster deformis smith (hymenoptera: Myrmicinae)

The secretion of the hypertrophied metapleural gland of the antCrematogaster deformis contains a mixture of phenols, consisting mainly of 3-propylphenol, 3-pentylphenol, 3,4-dihydro-8-hydroxy-3-methylisocoumarin (mellein), 5-propylresorcinol, and 5-pentylresorcinol. The secretion is released, as a repellent, when the highly vulnerable petiolar-postpetiolar region of the abdomen is attacked by enemy ants. In addition, small amounts of the secretion are released regularly to serve as an antiseptic, which is considered the original function of the gland. The secretion also has some insecticidal properties.

Pheromone-XLII. 1,3,6,9-nonadecatetraen, das sexualpheromon des frostspanners operophtera brumata (geometridae).

Abstract By means of GC and GCMS analysis and electrophysiological investigations ( z 3, z 6, z 9)-1,3,6,9-nonadecatetrane was identified as sex pheromone of the winter moth O . brumata , and prepared by stereoselective synthesis methods.

Dendrimers with Carbon Rich-Cores

Carbon rich compounds such as C60 buckminsterfullerene, conjugated oligoynes, and single-walled carbon nanotubes offer advantages as core templates for the design of dendrimers with a predefined shape because of their rigid structures. I h-symmetrical C60 permits the stereochemically-controlled attachment of anchor groups for the addition of dendrons and allows the realization of the formation of perfect spherical dendrimers and of variable addition patterns. The dendronization of fullerenes improves their solubility and provides the carbon sphere with additional chemical and physical properties. Medium-chain oligoynes are used as one-dimensional core tectons, decorated with dendritically branched end-caps. Single-walled carbon nanotubes represent tubular templates for cylindrical dendrimeric nanostructures.

Synthesis of a Biotinated Lipofullerene as a New Type of Transmembrane Anchor

As a prototype for a new class of lipid membrane components, the lipophilic fullerene derivative (so-called lipofullerene) 1 was synthesized and characterized. This mixed [1:5]-hexakisadduct consists of ten long alkyl chains within five didodecyl malonate addends and a linker malonate carrying a (+)-biotin unit as part of an amphiphilic spacer. The malonates are attached to the fullerene core in an octahedral addition pattern, which was achieved by two successive cyclopropanation sequences with the functional precursor malonate 8 and dodecyl malonate 10. The final step of the synthesis of 1 was the attachment of activated biotin 5 with the deprotected precursor 11. Binding experiments followed by reflectometric interference spectroscopy [RIfS] proved the capability of 1 to bind specifically the protein streptavidin (SA) through the biotin unit. The amphiphilic behavior of 1 was demonstrated by Langmuir Blodgett (LB) film investigations.

Nanospheres from Polymerized Lipofullerenes

Remarkably mechanically stable spherical nanostructures are formed by UV-initiated polymerization from polymerizable lipofullerene 1 in multilamellar lipid vesicles. The polymer beads can be filled or hollow. R=COO(CH2)9C≡C−C≡C(CH2)4CH3.

Host Attractants for Red Weevil, Rhynchophorus ferrugineus: Identification, Electrophysiological Activity, and Laboratory Bioassay

A steam distillate from the freshly cut young bark of coconut palm Cocos nucifera was analyzed by gas chromatography, combined gas chromatography–electroantennographic detection (GC-EAD) and GC-MS to detect host attractants for the curculionid weevil Rhynchophorus ferrugineus, one of the major coconut pests in Sri Lanka. A twin FID peak consisting of a minor and a major component was shown to possess electrophysiological (EAG) activity. The minor peak was identified as γ-nonanoic lactone 1, while the major peak was identified as 4-hydroxy-3-methoxystyrene 2. In an EAG assay the synthetic racemic nonanoic lactone 1 did not elicit a considerable response in the antenna of R. ferrugineus, whereas the laboratory synthesized 2 showed activity. In a laboratory bioassay using a Y-type olfactometer, synthetic 1 and 2 elicited moderate attractant properties to R. ferrugineus, whereas a 1:1 mixture of the compounds showed increased attraction over that of the individual compounds.