17042-21-6Relevant academic research and scientific papers
H2O2/HCl system: Oxidation-chlorination of secondary alcohols to α,α′-dichloro ketones
Nikishin, Gennady I.,Kapustina, Nadezhda I.,Sokova, Lyubov' L.,Bityukov, Oleg V.,Terent'ev, Alexander O.
, (2020)
The one-pot oxidation-chlorination of secondary alcohols to give α,α′-dichloro ketones in 62–80percent yields is reported. The convenient and readily available H2O2/HCl system acts on secondary alcohols (C5-C17) with the formation of α,α′-dichloro ketones. The reaction proceeds with high selectivity under the reported conditions; during this process peroxide formation and the Baeyer-Villiger oxidation reactions are not observed.
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.
Synthesis and reactivity of α-sulfenyl-β-chloroenones, including oxidation and Stille cross-coupling to form chalcone derivatives
Kearney, Aoife M.,Murphy, Linda,Murphy, Chloe C.,Eccles, Kevin S.,Lawrence, Simon E.,Collins, Stuart G.,Maguire, Anita R.
supporting information, (2021/05/04)
The synthesis of a range of novel α-sulfenyl-β-chloroenones from the corresponding α-sulfenylketones, via a NCS mediated chlorination cascade, is described. The scope of the reaction has been investigated and compounds bearing alkyl- and arylthio substituents have been synthesised. In most instances, the Z α-sulfenyl-β-chloroenones were formed as the major products, while variation of the substituent at the β-carbon position led to an alteration in stereoselectivity. Stille cross-coupling with the Z α-sulfenyl-β-chloroenones led to selective formation of Z sulfenyl chalcones, while the E α-sulfenyl-β-chloroenones did not react under the same conditions. Oxidation of the Z α-sulfenyl-β-chloroenones was followed by isomerisation, leading to the E α-sulfinyl-β-chloroenones. Stille cross-coupling with the E α-sulfinyl-β-chloroenones produced the E sulfinyl chalcones. Either the E or Z sulfinyl chalcones can be obtained by altering the sequence of oxidation and Stille cross-coupling.
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.
A simple and convenient method for direct α-chlorination of ketones with ammonium chloride and Oxone
Zhou, Zhong Shi,Li, Li,He, Xue Han
, p. 1213 - 1216,4 (2020/09/16)
When ketones were treated with ammonium chloride and Oxone in MeOH at room temperature, a direct α-chlorination of ketones was occurred and a series of the corresponding α-chloroketones were obtained in moderate to good yields after 24 h. In this reaction, ammonium chloride was used as the source of chlorine and Oxone was used as an oxidant. This method was simple, convenient and providing a novel procedure for preparation of α-chloroketones.
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.
Synthesis of α-diazoketone by the action of diazoalkanes on propionic anhydride
Gupta, Shalini,Agarwal,Garg, Poonam
body text, p. 2939 - 2942 (2010/11/05)
Propionic anhydride reacts with diazo-n-alkanes in dry ether at 0°C gave 1-diazo-1-n-alkyl butanones.
Highly enantioselective direct organocatalytic α-chlorination of ketones
Marigo, Mauro,Bachmann, Stephan,Halland, Nis,Braunton, Alan,Jorgensen, Karl Anker
, p. 5507 - 5510 (2007/10/03)
A C2-symmetric diamine serves as the organocatalyst in an asymmetric α-chlorination reaction of simple ketones (e.g., cyclohexanone, diethyl ketone). Optically active α-chloroketones are formed with excellent enantioselectivities using N-chlorosuccinimide (NCS) as the chlorine source (see scheme). These products have broad synthetic utility, in particular for pharmaceutical applications.
Total Synthesis of Ionomycin Using Ring-Opening Strategies
Lautens, Mark,Colucci, John T.,Hiebert, Sheldon,Smith, Nicholas D.,Bouchain, Giliane
, p. 1879 - 1882 (2007/10/03)
(Matrix Presented) The total synthesis of the polyether antibiotic ionomycin, a calcium ionophore, is described. The synthesis demonstrates the utility of ring-opening methodologies as applied to the synthesis of polypropionate and deoxypolypropionate subunits, which are found in two of the four fragments in the synthesis.
