- Method for preparing alpha,alpha-dichloroketone under solvent-free condition
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The invention provides a method for synthesizing an alpha,alpha-dichloroketone compound by taking methyl ketone and sulfonyl chloride as raw materials. The method comprises the following steps: heating a reaction mixture of methyl ketone and sulfonyl chloride to 80 DEG C under a dry air condition, stirring for 4-8 hours, after the reaction is finished, removing sulfonyl chloride from the obtained mixture, and carrying out silica gel column chromatography separation by taking ethyl acetate-hexane as an eluent to obtain the alpha,alpha-dichloroketone compound. The synthesis method provided by the invention has the advantages of extremely high chemical reactivity and selectivity, simple and easily available raw materials, low price, simple operation, no need of any catalyst and solvent, reduction of the synthesis cost and the pollution of organic solvents to the environment, greenness, economy and the like.
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Page/Page column 7-8
(2021/06/21)
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- Solvent-free preparation of α,α-dichloroketones with sulfuryl chloride
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An efficient and facile method is reported for the synthesis of a series of α,α-dichloroketones. The direct dichlorination of methyl ketones and 1,3-dicarbonyls using an excess amount of sulfuryl chloride affords the corresponding gem-dichloro compounds in moderate to excellent yields. Moreover, the protocol features high yields, broad substrate scope, and simple reaction conditions without using any catalysts and solvents.
- Tu, Dewei,Luo, Juan,Jiang, Wengao,Tang, Qiang
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supporting information
(2021/09/15)
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- Novel synthesis method of metribuzin intermediate
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The invention discloses a novel synthesis method of a metribuzin intermediate, wherein the intermediate triazinone of metribuzin is produced by using pinacolone (methyl tert-butyl ketone) as an initial raw material through reaction steps of chlorination, hydrolysis, oxidation, condensation and the like. According to the invention, the reaction conditions are mild, and the total yield reaches 92.4%; hydrogen peroxide is used as an oxidizing agent for replacing sodium hypochlorite, and the oxidation reaction is carried out at a room temperature, so that the operation is convenient, and the byproduct is water so as to avoid the discharge of pollutants such as salt-containing wastewater and the like in the production process; and after the reaction is finished, the intermediate and the catalyst are subjected to chromatographic separation so as to recycle the water phase containing the catalyst.
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Paragraph 0015; 0019; 0023
(2020/01/25)
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- Production process of dichloro pinacolone (by machine translation)
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The production process is characterized in that the specific production process is as follows: S1: 2 - Chloropentane preparation. S2: pinacolone. S3: pinacolone rectification. S4: synthesis of dichloro-pinacolone. S5: treatment of by-products. In addition, by adopting formaldehyde addition in the chlorination reaction, the reaction rate 3 times or more can be inhibited, and reaction and cooling can be completed between a general reaction requirement 70 - 75 hours by adding formaldehyde, and cooling by adopting chilled water, so that the production efficiency is greatly improved 20 - 25 hours. (by machine translation)
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Paragraph 0011
(2020/12/29)
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- H2O2/HCl system: Oxidation-chlorination of secondary alcohols to α,α′-dichloro ketones
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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.
- Nikishin, Gennady I.,Kapustina, Nadezhda I.,Sokova, Lyubov' L.,Bityukov, Oleg V.,Terent'ev, Alexander O.
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supporting information
(2020/07/13)
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- Dichloropinacolin production process
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The invention relates to a dichloropinacolin production process, which is characterized in that the specific production process is as follows: S1: preparation of 2-chloroisopentane; S2: synthesis of pinacone; S3: rectification of the pinacone; S4: synthesis of the dichloropinacolin; S5: treatment of byproducts. Excessive chlorine gas is adopted in a pinacone chlorination reaction, so that the pinacone can completely react; and in addition, formaldehyde is adopted to be added in the chlorination reaction, so that the generation of trichloropinacolin can be inhibited, and the reaction rate can be increased by more than 3 times at the same time; the general reaction takes 70-75 hours, and the reaction can be completed in 20-25 hours by adding formaldehyde.
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Paragraph 0009; 0011
(2019/04/17)
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- A simple, mild, and efficient method for the preparation of α,α-dichloroketones with DCDMH catalyzed by ammonium chloride
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New process that can selectively prepare α,α-dichloro ketones from various ketones with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) using ammonium chloride as a catalyst is reported. The effects of ammonium salts, solvents, DCDMH, and reaction temperature were investigated. Under the optimal condition, most of α,α-dichlorinated products were selectively obtained in 86-98% yield.
- Zheng, Zubiao,Han, Bingbing,Cheng, Peng,Niu, Jiangxiu,Wang, Aidong
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p. 9814 - 9818
(2015/01/09)
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- Identification of organic reaction products in the absence of additivity of chromatographic retention indices. Chloro derivatives of methyl-tert-butyl ketone
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As a result of a joint interpretation of mass spectra and gas chromatographic retention indices more than ten products of free radical chlorination of methyl-tert-butyl ketone are identified. They contain from one to six chlorine atoms in the molecule and were not previously characterized either by mass spectrometric or chromatographic reference data. It is found that retention index increments corresponding to a gradual increase in the number of chlorine atoms in the molecule per unit are non-additive and vary in wide ranges (from 53 i.u. to 219 i.u.), which does not hinder the use of separate elements of additive schemes for the estimation of the indices of products of such non-regioselective reactions.
- Zenkevich,Eliseenkov,Kasatochkin
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p. 505 - 514
(2013/07/26)
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- Simple and efficient methods for selective preparation of α-mono or α,α-dichloro ketones and β-ketoesters by using DCDMH
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New processes that can selectively prepare α-mono or α,α-dichloro ketones and β-ketoesters using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) are reported. Using silica gel as the catalyst and methanol as the solvent and heating for 1 h under reflux, α-monochlorinated products were selectively obtained in 86-98% yield. However using a deep eutectic solvent (choline chloride: p-TsOH = 1:1) as the solvent and stirring for 45 min at room temperature, α,α- dichlorinated products were selectively obtained in 86-95% yield.
- Chen, Zizhan,Zhou, Bin,Cai, Huihua,Zhu, Wei,Zou, Xinzhuo
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experimental part
p. 275 - 278
(2010/04/22)
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- Selective halogenation of ketones
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The present invention provides a process and apparatus for selectively halogenating a ketone of the formula (I) wherein R represents unsubstituted or halogen-substituted C1-C16-alkyl, or aryloxy, R1, R2 and R3 independently represent hydrogen, halogen, C1-C16-alkyl or aryl, the process involving heating the ketone to reflux in a reaction vessel such that the ketone vapor contacts a condensor attached to the reaction vessel and condenses, reacting the condensed ketone with halogen gas, and collecting the selectively halogenated ketone in the reaction vessel.
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- Synthesis, fragmentations and rearrangements of 3-(1-haloalkyl) oxaziridines
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A variety of new 3-(1-haloalkyl)oxaziridines was synthesized by oxidation of α-chloro-, α-bromo-, α,α-dichloro-, α,α-dibromo- and α,α,α-trichloroaldimines with meta-chloroperbenzoic acid. Attempts to induce dehydrohalogenation into the elusive methyleneoxaziridines were unsuccessful. However, presumptive evidence is presented that 2-t-butyl-3-(trichloromethyl)oxaziridine is dehydrochlorinated into a transient methyleneoxaziridine, which underwent valence isomerization into an intermediate iminooxirane, the latter being fragmented into t-butyl isocyanide. Various types of reactions of the title compounds are reported. Among others, 2-alkyl-3-(1-chloro-1-methyl) ethyloxaziridines rearranged with methyllithium into 2-(N-alkyl)aminoisobutyraldehydes.
- De Kimpe, Norbert,De Corte, Bart
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p. 7345 - 7362
(2007/10/02)
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- Halogenation Using Quaternary Ammonium Polyhalides. XXXII. Dichlorination of Aromatic Acetyl Derivatives with Benzyltrimethylammonium Tetrachloroiodate
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The reaction of aromatic acetyl derivatives with 2 molar amounts of benzyltrimethylammonium tetrachloroiodate in acetic acid at 70 deg C for several hours gave dichloroacetyl derivatives in good yields.
- Kakinami, Takaaki,Urabe, Yasuaki,Hermawan, Irwan,Yamanishi, Hiroko,Okamoto, Tsuyoshi,Kajigaeshi, Shoji
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p. 2549 - 2551
(2007/10/02)
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- Process and intermediates for the synthesis of diastereomeric compounds
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A new process for the controlled synthesis of the two diasteromeric forms of triazolyl-O,N-acetals of the formula STR1 in which R represents optionally substituted phenyl, optionally substituted phenoxy, optionally substituted alkoxy, optionally substituted alkoxy, optionally substituted alkylthio, alkylcarbonyl, nitro or halogen and n represents an integer from 0 to 5, with the proviso that R can represent identical or different radicals, if n represents an integer from 2 to 5. New trans-substituted oxiranes and their use as intermediates for the synthesis of compounds of the formula (I).
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- Halogen Epoxides, 7. Rearrangements during the Reaction of Substituted 2-Chloro- and 2,3-Dichlorooxiranes with Silver Tetrafluoroborate
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Reactions of tert-butyl-substituted and of isopropyl-substituted chlorooxiranes with silver tetrafluoroborate have been examined.Dehalogenations in the 2-positions of 2-chloro-2-tert-butyl- (5) and of 2-chloro-2-isopropyl-substituted oxiranes (35) occurred without changes of the carbon skeletons.By contrast, dehalogenations in the 2-positions of 2-chloro-3-tert-butyl- (12) and of 2-chloro-3-isopropyloxiranes (35) afforded partly rearranged products by 1,2-methyl- and/or 1,2-hydride shifts to the corresponding α-ketocarbenium ions.
- Keul, Helmut,Pfeffer, Bernd,Griesbaum, Karl
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p. 2193 - 2204
(2007/10/02)
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