6084-17-9Relevant academic research and scientific papers
CV-driven Optimization: Cobalt-Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR
Tian, Siyu,Lv, Shide,Jia, Xiaofei,Ma, Li,Li, Baoying,Zhang, Guofeng,Gao, Wei,Wei, Yingqin,Chen, Jianbin
supporting information, p. 5626 - 5633 (2019/11/22)
Instead of screening reaction conditions by yield-based chemical trial-and-error, potential-based cyclic voltammetry was alternatively employed for optimization of electrochemical oxychlorination of alkenes. With this unconventional screening method, the catalyst system including catalysts, molar ratio of chloride sources and solvents were identified in a rational, time- and energy-efficient manner. The optimal catalytic system in combination with oxygen reduction reaction enabled broad substrate scopes for the desired transformation by taking advantages of persistent radical effect. UV-vis and CV titration experiments confirmed the in-situ formed catalytic species [CoCl5]. Moreover, cyclic voltammetry was applied to obtain mechanistic insights in our reaction system. (Figure presented.).
The Mn-catalyzed paired electrochemical facile oxychlorination of styrenes: Via the oxygen reduction reaction
Tian, Siyu,Jia, Xiaofei,Wang, Ling,Li, Baoying,Liu, Siyuan,Ma, Li,Gao, Wei,Wei, Yingqin,Chen, Jianbin
supporting information, p. 12104 - 12107 (2019/10/14)
Reported herein is the electrochemical engendering of chlorine radicals by a manganese catalyst with a controllable pattern, and inexpensive MgCl2 as the chlorine source. In combination with the oxygen reduction reaction, chloroacetophenones were synthesized with abundant styrene as the feedstock in good to excellent yields.
Efficient α-chlorination of carbonyl containing compounds under basic conditions using methyl chlorosulfate
Silva, Saúl,Maycock, Christopher D.
supporting information, p. 1233 - 1238 (2018/02/27)
An efficient method for the α-chlorination of ketones under basic conditions is described using methyl chlorosulfate. Its applicability for the chlorination of other functional groups has also been studied and it is equally useful for the synthesis of α-chloroesters and amides. Methyl chlorosulfate is described for the first time as a positive chlorine source. Some aldol reactions which occur during the chlorination of some substrates are also reported.
A Simple and Efficient Method for the Preparation of α-Halogenated Ketones Using Iron(III) Chloride and Iron(III) Bromide as Halogen Sources with Phenyliodonium Diacetate as Oxidant
Tang, Shi-Zhong,Zhao, Wenshuang,Chen, Tao,Liu, Yang,Zhang, Xiao-Ming,Zhang, Fu-Min
supporting information, p. 4177 - 4183 (2017/12/18)
α-Halogenated ketones are both unique structure moieties existing in biologically natural products and valuable synthetic intermediates for the preparation of functional molecules. An efficient and scalable method for the preparation of α-halogenated ketone using iron (III) chloride and iron (III) bromide as halogen sources with phenyliodonium diacetate as oxidant has been developed, featuring mild reaction conditions, environmentally friendly reagents, and wide substrate scope. Notably, the three-step synthesis of drug prasugrel was achieved using this developed method as a key step with 30% yield on gram-scale. Additionally, the reaction mechanism involving chloride cation was proposed based on some preliminary control experiments. (Figure presented.).
α,α-Alkylation-Halogenation and Dihalogenation of Sulfoxonium Ylides. A Direct Preparation of Geminal Difunctionalized Ketones
Gallo, Rafael D. C.,Ahmad, Anees,Metzker, Gustavo,Burtoloso, Antonio C. B.
, p. 16980 - 16984 (2017/11/27)
A one-pot alkylation–halogenation of ketosulfoxonium ylides in the presence of alkyl halides is described. The method furnishes several gem-difunctionalized haloketones (an alkyl and F, Cl, Br, or I) in good yields. Replacing alkyl halides with a mixture of electrophilic halogen species and various halide anions led to gem-dihalogenated ketones containing a combination of the same or two different halogens. Kinetic isotopic effects as well as reaction kinetic experiments give insight to the mechanism of these reactions.
Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis
Hering, Thea,Mühldorf, Bernd,Wolf, Robert,K?nig, Burkhard
supporting information, p. 5342 - 5345 (2016/04/26)
Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal-catalyzed cross-couplings. Nature chlorinates with chloride anions, FAD-dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket. Chlorination of arenes with chloride anions: The photochemical analogue of the enzymatic chlorination of Flavin-adenine dinucleotide (FAD)-dependent halogenases is possible in the presence of riboflavin, air, acetic acid, and blue light (see scheme; RFT=riboflavin tetraacetate).
Preparation methods for ephedrine or pseudoephedrine and for ephedrine or pseudoephedrine intermediate
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Paragraph 0089; 0090; 0092; 0093; 0094; 0095; 0096-0099, (2017/04/14)
The invention discloses a preparation method for an ephedrine or pseudoephedrine intermediate. The preparation method comprises the following steps: with 2-chloropropionyl chloride and benzene as starting materials, carrying out the Friedel-Crafts reaction under the catalysis of Lewis acid so as to produce 2-chloro-1-phenyl-1-acetone; and reacting produced 2-chloro-1-phenyl-1-acetone with methylamine in an aprotic solvent so as to produce 2-methylamino-1-phenyl-1-acetone. The invention also discloses a preparation method for ephedrine or pseudoephedrine. According to the methods, phosphorus trichloride with severe pollution is not used anymore, and dangerous and expensive bromine is not used any longer; the Friedel-Crafts reaction and methylamination are carried out in the same solvent, so cost for public works is saved; and a safe, simple, cheap, green and novel process is provided for synthesis of ephedrine and pseudoephedrine.
Iodine(III)-Mediated Oxidative Hydrolysis of Haloalkenes: Access to α-Halo Ketones by a Release-and-Catch Mechanism
Jobin-Des Lauriers, Antoine,Legault, Claude Y.
supporting information, p. 108 - 111 (2016/01/15)
An unprecedented iodine(III)-mediated oxidative transposition of vinyl halides has been accomplished. The products obtained, α-halo ketones, are useful and polyvalent synthetic precursors. There are only a handful of reported examples of the direct conversion of vinyl halides to their corresponding α-halo carbonyl compounds. Insights into the mechanism and demonstration that this synthetic transformation can be done under enantioselective conditions are reported.
Vanadium-catalyzed chlorination under molecular oxygen
Moriuchi, Toshiyuki,Fukui, Yasuhiro,Kato, Satoshi,Kajikawa, Tomomi,Hirao, Toshikazu
, p. 177 - 180 (2015/03/04)
A catalytic chlorination of ketones was performed by using a vanadium catalyst in the presence of Bu4NI and AlCl3 under atmospheric molecular oxygen. This catalytic chlorination could be applied to the chlorination of alkenes to give the corresponding vic-dichlorides. AlCl3 was found to serve as both a Lewis acid and a chloride source to induce the facile chlorination. A combination of Bu4NI and AlI3 in the presence of a vanadium catalyst under atmospheric molecular oxygen induced the iodination of ketones.
Direct conversion of alcohols to α-chloro aldehydes and α-chloro ketones
Jing, Yuanyuan,Daniliuc, Constantin G.,Studer, Armido
supporting information, p. 4932 - 4935 (2015/04/27)
Direct conversion of primary and secondary alcohols into the corresponding α-chloro aldehydes and α-chloro ketones using trichloroisocyanuric acid, serving both as stoichiometric oxidant and α-halogenating reagent, is reported. For primary alcohols, TEMPO has to be added as an oxidation catalyst, and for the transformation of secondary alcohols (TEMPO-free protocol), MeOH as an additive is essential to promote chlorination of the intermediary ketones.
