17042-21-6Relevant articles and documents
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Naidu,Mahadevappa
, p. 269,271,272,273 (1978)
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An efficient synthesis of (S)-(+)-manicone, an alarm pheromone of Manica ants
De Kimpe, Norbert,Aelterman, Wim
, p. 12815 - 12820 (1996)
Manicone [(4E,6S)-(+)-4,6-dimethyl-4-octen-3-one], an alarm pheromone component of Manica ants, was synthesized by a five-step sequence starting from 2-chloro-3-pentanone. The latter α-chloro ketone was converted into the corresponding N-isopropyl ketimine, which was sequentially alkylated via its 3-chloro-1-azaallylic anion with (S)-(+)-2-methyl-1-bromobutane. 1,2-Dehydrochlorination of the resulting chiral functionalized α-chloro ketimine, followed by acid hydrolysis and final Rh(III)-chloride-mediated isomerization afforded the pheromone (S)-(+)-manicone in enantiopure form.
Rapid degradation of cyclic peroxides by titanium and antimony chlorides
Bali, Mark S.,Armitt, David,Wallace, Lynne,Day, Anthony I.
, p. 6775 - 6783 (2015/04/14)
First responders face extraordinary risks when dealing with organic peroxides such as TATP due to the extreme sensitivity of this class of explosives, and to a lack of a robust chemical means of safe and rapid neutralisation. The Lewis acids TiCl4 and SbCl3 have been found to demonstrate a novel degradation mechanism, with TiCl4 degrading a model cyclic peroxide in minutes when used in a two-fold excess, or ～3 hours at half equivalence. The products cannot re-form peroxide compounds as is the case with acid degradation, suggesting the two mechanisms are fundamentally different. The Lewis acids mediate a rearrangement reaction in the cyclic peroxide backbone leading to relatively innocuous products through deactivation of oxidising O. Sub-stoichiometric TiCl4 reactions highlight a secondary reaction pathway that also leads to some oxidative chlorination products, possibly mediated by an unconfirmed titanium-oxychloride species. SbCl3 was found to exhibit similar reactivity to TiCl4, although at a slower rate. A mechanism is proposed, consistent with the observations for both stoichiometric and sub-stoichiometric quantities of TiCl4.
Products and mechanism of the reaction of chlorine atoms with 3-pentanone in 700-950 Torr of N2/O2 diluent at 297-515 K
Kaiser,Wallington,Hurley
experimental part, p. 343 - 354 (2010/06/15)
The products, kinetics, and mechanism of the reaction Cl + 3-pentanone have been measured by UV irradiation of Cl2/3-pentanone/N2 (O2) mixtures using primarily GC analysis with selected cross checks by FTIR. In the absence of O2, the products are 1- and 2-chloro-3-pentanone with yields of 21 and 78%, respectively. As the temperature is increased, the yield of 1-chloro-3-pentanone increases modestly relative to the 2-chloro-3-pentanone yield. On the basis of this increase, the activation energy for hydrogen abstraction at the 1 position is determined to be 500 (±500) cal mole-1 relative to abstraction at the 2 position. In the presence of 500 ppm of O2 with 900-1000 ppm of Cl2 at 297 K, the yield of 2-chloro- 3-pentanone decreases dramatically from 78 to 2.5%, while the 1-chloro-3-pentanone decreases only modestly from 21 to 17%. The observed oxygenated species are acetaldehyde (59%), 2,3-pentanedione (9%), and propionyl chloride (56%). Increasing the temperature to 420 K (O2 = 500 ppm) suppresses these oxygenated products, and 2-chloro-3-pentanone again becomes the primary product, indicating that the O2 addition reaction to the 2-pentanonyl radical has become reversible. At 500 K and 10 000 ppm O 2, a new product channel opens which forms a small yield (～4%) of ethylvinylketone. Computer modeling of the product yields has been performed to gain an understanding of the overall reaction mechanism in the presence and absence of O2. The reaction of chlorine atoms with 3-pentanone proceeds with a rate constant of 8.1 (±0.8) × 10-11 cm3 molecule-1 s-1 independent of temperature over the range of 297-490 K (Ea = 0 ± 200 cal mole-1). Rate constant ratios of K(C2H 5C(O)CHCH3 + Cl2)/ k(C2H 5C(O)CHCH3 + O2) = 0.0185 ± 0.0037 and k(C2H5C(O)CH2CH + Cl2)/ k(C 2H5CH2C(O)CH2CH2 + O 2) = 2.7 ± 0.4 were determined at 297 K in 800-950 Torr of N2/O2 diluent. In 800-950 Torr of N2/O 2 diluent, the major fate of the alkoxy radical CH 3CH(O)C(O)C2H5 is decomposition to give C 2H5C(O) radicals and CH3CHO. These results show that the chemical mechanisms of the 3-pentanone reactions are very similar to those observed for butanone. In addition, the rate constants of the reactions of chlorine atoms with 1-chloro-3-pentanone [3 (±0.6) x 10-11 over the range of 297-460 K], 2,3-pentanedione [1.4 (±0.3) × 10-11 at 297 K], and ethylvinylketone [1.9 (±0.4) × 10-10 over the range of 297-400 K, decreasing rapidly above 400 K] were measured at ambient pressure.
