2277-18-1Relevant academic research and scientific papers
Treasures from the Free Radical Renaissance Period - Miscellaneous hexenyl radical kinetic data
Beckwith, Athelstan L. J.,Schiesser, Carl H.
experimental part, p. 1736 - 1743 (2011/05/03)
Rate constant data and Arrhenius parameters have been determined for a series of substituted hexenyl radicals of differing electronic and steric demand. Electron-withdrawing groups (CF3, CO2Et) directly attached to the radical centre slighly accelerate 5-exo ring-closure (k cis + ktrans ～ 2.1 × 105 s -1 at 25°) relative to donating groups (OMe; 1.6 × 10 5 s-1 at 25°). Sterically demanding groups (tert-Bu), as expected, slow the cyclization process (1 × 105 s -1). These observations are consistent with subtle changes in activation energy for 5-exo ring-closure. Interestingly, the nature of the solvent would appear to have a significant influence on this chemistry with the cis/trans stereoselectivity sometimes improved as the solvent polarity is increased. Except for the system containing the CF3 (electron-withdrawing) group which displays an increase in the cyclization/capture rate constant (kc/kH), a general decrease in the kc/kH ratio as solvent polarity is increased is noted; these changes have been speculated to arise mainly from changes in kH in the various solvents employed.
PROCESS FOR THE DIRECT CONVERSION OF LACTONES INTO UNSATURATED KETONES OR ALDEHYDES
-
Page 10, (2008/06/13)
The present invention refers to a process for the preparation of unsaturated ketones or aldehydes by pyrolysis of a lactone, in the presence of a reducing agent such as molecular hydrogen or a carboxylic acid, and in the presence of a catalyst, optionally
Synergistic sex pheromone components of white-spotted tussock moth, Orgyia thyellina
Gries, Gerhard,Clearwater, John,Gries, Regine,Khaskin, Grigori,King, Skip,Schaefer, Paul
, p. 1091 - 1104 (2007/10/03)
In 1996, the exotic white-spotted tussock moth (WSTM), Orgyia thyellina (Lepidoptera: Lymantriidae), was discovered in Auckland, New Zealand. Because establishment of WSTM would threaten New Zealand's orchard industry and international trade, eradication of WSTM with microbial insecticide was initiated. To monitor and complement eradication of WSTM by capture of male moths in pheromone-baited traps, pheromone components of female WSTM needed to be identified. Coupled gas chromatographic-electroantennographic detection analysis of pheromone gland extract revealed several compounds that elicited responses from male moth antennae. Mass spectra of the two most EAD-active compounds suggested, and comparative GC-MS of authentic standards confirmed, that they were (Z)-6-heneicosen-11-one (Z6-11-one) and (Z)-6-heneicosen-9- one, the latter termed here 'thyellinone.' In field experiments in Japan, Z6- 11-one plus thyellinone at a 100:5 ratio attracted WSTM males, whereas either ketone alone failed to attract a single male moth. Addition of further candidate pheromone components did not enhance attractiveness of the binary blend. Through the 1997-1998 summer, 45,000 commercial trap lures baited with 2000 μg of Z6-11-one and 100 μg of thyellinone were deployed in Auckland towards eradication of the residual WSTM population.
