Iliya Ognyanov

Antifeeding activity of rotenone and some derivatives towards selected insect storage pests

Abstract Roteneone and five of its derivatives prepared by appropriate chemical transformations were tested for their feeding deterrrent activity against the adults of Sitophilus granarius and Tribolium confusum , as well as against the larvae of Trilobium confusum and Trogoderma granarium . The strongest deterrent activity against all species was exhibited by rotenone. The total coefficient was 200, which is the maximum value attainable for this kind of test. Rotenone is thus the best antifeedant so far tested in our laboratory. The antifeeding activity of the derivatives of rotenone was considerably lower, but showed a certain selectivity.

Transannular cyclisation of germacrone and isogermacrone via oxymercuration-demercuration

Abstract Germacrone 1 undergoes transannular cyclisation by OM-DM yielding the trans -decalin derivatives 3 , 4 and 5 . Isogermacrone 2 similarly yields 3 , 4 and 5 and, as a minor product, the ketone 8 . The stereochemistry and the mechanism of the intramolecular olefinic cyclisation are discussed.

Sesquiterpene lactones in a population of Balsamita major cultivated in bulgaria

Abstract Seven C-9β-hydroxylated or esterified germacranolides were isolated from the flowers of a Balsamita major population cultivated in Bulgaria: the known 9β-propionyloxy- and 9β-isobutyryloxy-costunolides, 1α,10β-epoxyhaageanolide, 9β-hydroxyartemorin, and the new esters the propionyl-, isobutyryl- and 2-methylbutyryl1α,10β-epoxyhaageanolides. These lactones differ from the presently known eudesmanolides found in a B. major population cultivated in Poland, probably as result of the existence of chemotypes, frequently observed in the tribe Anthemideae.

Chemical Composition of Essential Oil from Mongolian Acorus calamus L. Rhizomes

ABSTRACT The rhizome oil of Acorus calamus L. was analyzed by GC and GC/MS and 30 compounds were identified, the main ones were shyobunones (17.3%) and acorenone (14.4%).

Determination of the stereochemistry of rotenoids by1H-NMR spectroscopy in C6D6

The application of1H-NMR spectroscopy in C6D6 for the determination of configurations at C12a and C6a in rotenoids is discussed.ZusammenfassungEs wird die Anwendung der1H-NMR-Spektroskopie in C6D6 zur Bestimmung der Konfigurationen an C12a und C6a in Rotenoiden diskutiert.