Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Jimenez-Aleman, G. H.; Schöner, T.; Montero-Alejo, A. L.; Brandt, W.; Boland, W.;Improved synthesis of the chrysomelid pheromone (6R,7S)-(+)-himachala-9,11-diene via spontaneous bromination and didehydrobromination of 2,6,6,9-tetramethyl-bicyclo[5.4.0]undec-8-eneARKIVOC2012371-378(2012)DOI: 10.3998/ark.5550190.0013.326
A convenient synthesis of (6R,7S)-(+)-himachala-9,11-diene, the pheromone of the chrysomelid beetle Phyllotreta striolata is described. The diene is obtained in a single operation by a spontaneous “bromination/dehydrobromination” of 2,6,6,9-tetramethylbicyclo[5.4.0]undec-8-ene. The halogenation/dehalogenation sequence proceeds spontaneously in CCl4, and is less uniform in CH2Cl2 and CHCl3. 1H NMR experiments carried out in presence of the radical scavenger di-tert-butyl-4-methylphenol suggest an ionic mechanism for this reaction. Theoretical calculations demonstrate that the spontaneous reaction profits from the strongly exergonic addition of Br2 to the double bond and an almost neutral energy difference between the starting olefin and the diene pheromone.