- 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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- A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions
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A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions has been developed. In the presence of PhI(OAc)2 as promoter and under ambient conditions, the reactions of styrenes and triiodomethane undergo the transformation smoothly to deliver the corresponding α-iodoketones without additional photocatalyst in good yields under sunlight irradiation. Meanwhile, the reactions of styrenes with tribromomethane and trichloromethane generate the desired α-bromoketones and α-chloroketones in high yields by using Ru(bpy)3Cl2 as a photocatalyst under blue LED (450–455 nm) irradiation.
- Wang, Zhihui,Wang, Lei,Wang, Zhiming,Li, Pinhua,Zhang, Yicheng
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supporting information
p. 429 - 432
(2020/02/29)
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- Facile Synthesis of α-Haloketones by Aerobic Oxidation of Olefins Using KX as Nonhazardous Halogen Source
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An operationally simple and safe synthesis of α-haloketones using KBr and KCl as nonhazardous halogen sources is reported. It involves an iron-catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible-light. This strategy avoids the risks associated with handling halo-contained electrophiles (Cl2, Br2, NCS, NBS). The process is tolerant to several functional groups, and extended to a range of substituted styrenes in up to 89% yield. A radical reaction pathway is proposed based on control experiments and spectroscopy studies.
- Luo, Zhibin,Meng, Yunge,Gong, Xinchi,Wu, Jie,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
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supporting information
p. 173 - 177
(2020/01/02)
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- Cascade Trisulfur Radical Anion (S3?-) Addition/Electron Detosylation Process for the Synthesis of 1,2,3-Thiadiazoles and Isothiazoles
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Trisulfur radical anion (S3?-) mediated reactions with in situ formed azoalkenes and α,β-usaturated N-sulfonylimines for the construction of 1,2,3-thiadiazoles and isothiazoles has been developed. S3?- is in situ generated from potassium sulfide in DMF. These two approaches provide a new, safe, and simple way to construct 4-subsituted 1,2,3-thiadiazoles, 5-subsituted 1,2,3-thiadiazoles, and isothiazole in good yields. The reactions include the formation of the new C-S and N-S bonds via S3?- addition and electron detosylation under mild conditions.
- Liu, Bei-Bei,Bai, Hui-Wen,Liu, Huan,Wang, Shun-Yi,Ji, Shun-Jun
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p. 10281 - 10288
(2018/07/25)
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- Facile and efficient preparation of α-halomethyl ketones from α-diazo ketones catalyzed by iron(III) halides and silica gel
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An efficient and mild method for the synthesis of α-halomethyl ketones from α-diazo ketones was developed using ferric chloride or bromide as the halogen source and silica gel as the hydrogen source, with good to excellent yields.
- Shi, Xinxia,Zhang, Lingqiong,Yang, Pengfei,Sun, Han,Zhang, Yilan,Xie, Chunsong,Ou-yang, Zhen,Wang, Min
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supporting information
p. 1200 - 1203
(2018/03/08)
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- Systematic Synthesis of Diphenyl-Substituted Carotenoids as Molecular Wires
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A general method for the construction of diphenyl-substituted carotenoids has been developed through the stereoselective synthesis of dienyl sulfones with a phenyl substituent. Systematic synthetic pathways to the dienyl sulfones were delineated starting from readily available acetophenones with para-substituent X of various electronic natures, which provided the carotenoids with diverse physicochemical characteristics. The sulfone olefination method together with the Ramberg–B?cklund reaction produced a 9,9′-cis-10,10′-diphenylcarotene and all-trans-9,9′-diphenylcarotenes. Conductance measurements of the all-trans carotenoids by the scanning tunnelling microscopy break-junction method revealed a positional effect of the phenyl groups as well as a polar effect of the phenyl substituent X according to the electronic nature.
- Lim, Boram,Oh, Eun-Taek,Im, JongOne,Lee, Kyu Sang,Jung, Hyunuk,Kim, Minsoo,Kim, Dahye,Oh, Jung Taek,Bae, Sung-Hee,Chung, Wook-Jin,Ahn, Kwang-Hyun,Koo, Sangho
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p. 6390 - 6400
(2017/12/01)
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- High-yielding aqueous synthesis of chloroacetophenones and aroyl chlorohydrins
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The use of large amounts of volatile organic solvents in industrial chemical processes contributes to widespread environmental pollution. To help solve this problem, water and a phase transfer catalyst were used to replace organic solvents in the transformations of bromoacetophenones into chloroacetophenones and aroyl epoxides into aroyl chlorohydrins. The reactions were promoted by sulfonyl chlorides and gave quantitative or close to quantitative yields. Notably, chromatographic purification, which is laborious and consumes large amounts of organic solvents, was not needed. These two processes have opened a green and cost-effective channel to prepare the chemical intermediates chloroacetophenones and aroyl chlorohydrins. The reaction mechanisms are discussed based on control experiments.
- Zhang, Xixi,Liu, Lei,Li, Chunbao
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p. 25339 - 25345
(2016/03/22)
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- Laboratory-Scale Membrane Reactor for the Generation of Anhydrous Diazomethane
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A configurationally simple and robust semibatch apparatus for the in situ on-demand generation of anhydrous solutions of diazomethane (CH2N2) avoiding distillation methods is presented. Diazomethane is produced by base-mediated decomposition of commercially available Diazald within a semipermeable Teflon AF-2400 tubing and subsequently selectively separated from the tubing into a solvent- and substrate-filled flask (tube-in-flask reactor). Reactions with CH2N2 can therefore be performed directly in the flask without dangerous and labor-intensive purification operations or exposure of the operator to CH2N2. The reactor has been employed for the methylation of carboxylic acids, the synthesis of α-chloro ketones and pyrazoles, and palladium-catalyzed cyclopropanation reactions on laboratory scale. The implementation of in-line FTIR technology allowed monitoring of the CH2N2 generation and its consumption. In addition, larger scales (1.8 g diazomethane per hour) could be obtained via parallelization (numbering up) by simply wrapping several membrane tubings into the flask.
- Dallinger, Doris,Pinho, Vagner D.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 5814 - 5823
(2016/07/26)
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- Experimental study on the reaction pathway of α-haloacetophenones with NaOMe: Examination of bifurcation mechanism
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The reaction of PhCOCH2Br and NaOMe in MeOH gave PhCOCH 2OH as the major product and PhCOCH2OMe as the minor product. Substituent effects on the reactivity and product selectivity revealed that an electron-withdrawing substituent on the phenyl ring enhanced the overall reactivity and gave more alcohol than ether. It was indicated that the alcohol was formed via carbonyl addition-epoxidation, whereas the ether was formed by direct substitution. Substituent effects on the reaction rates, as well as the effects of NaOMe concentration on the rate and product ratio for both reactions of PhCOCH2Br and PhCOCH2CI are in line with the mechanism that the alcohol and ether products were formed via two independent and concurrent routes, carbonyl addition and a-carbon attack, respectively, and thus the reaction mechanism could be different from the bifurcation mechanism previously predicted for the reaction of PhCOCH2Br by a simulation study in the gas phase.
- Tagawa, Kohei,Sasagawa, Keita,Wakisaka, Ken,Monjiyama, Shunsuke,Katayama, Mika,Yamataka, Hiroshi
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p. 119 - 126
(2014/02/14)
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- Direct conversion of alcohols to α-chloro aldehydes and α-chloro ketones
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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.
- Jing, Yuanyuan,Daniliuc, Constantin G.,Studer, Armido
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supporting information
p. 4932 - 4935
(2015/04/27)
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- A one-pot method synthesis of α-chloroketone dimethyl acetals
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A new one-pot method has been developed for the direct preparation of α-chloroketone dimethyl acetals from ketones using ammonium chloride as the source of chlorine and potassium monoperoxysulfate as the oxidant in the presence of trimethyl orthoformate in methanol at room temperature. Ketones which have electron-withdrawing groups on the aryl rings gave the corresponding a-chloroketone dimethyl acetals in moderate to good yields.
- Zhou, Zhong-Shi,Li, Li,He, Xue-Han
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p. 633 - 635
(2013/11/06)
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- Target-oriented synthesis: Miscellaneous synthetic routes to access 1,4-enediones through the coupling of 1,3-dicarbonyl compounds with multiform substrates
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Target-oriented synthetic protocol was presented for the synthesis of 1,4-enediones. The approach can efficiently construct 1,4-enediones through different reaction pathways from multiform substrates α-halo aromatic ketones, 2-hydroxy-aromatic ketones and methyl carbinols. In this reaction, CuI was found to be the most efficient catalyst. Multiform substrates were also found to perform well to afford the products in a one-pot fashion.
- Zhu, Yan-Ping,Cai, Qun,Gao, Qing-He,Jia, Feng-Cheng,Liu, Mei-Cai,Gao, Meng,Wu, An-Xin
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p. 6392 - 6398
(2013/07/25)
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- A simple and convenient method for direct α-chlorination of ketones with ammonium chloride and Oxone
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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.
- Zhou, Zhong Shi,Li, Li,He, Xue Han
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p. 1213 - 1216,4
(2020/09/16)
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- Combining designer cells and click chemistry for a one-pot four-step preparation of enantiopure β-hydroxytriazoles
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The multistep catalytic process using designer cells, either added as freshly prepared suspensions or as stable lyophilized powder, and click reaction can be performed in one pot. The sequence of four reactions allows the production of both enantiomers of β-hydroxytriazoles with high enantiomeric excess.
- Szymanski, Wiktor,Postema, Christiaan P.,Tarabiono, Chiara,Berthiol, Florian,Campbell-Verduyn, Lachlan,De Wildeman, Stefaan,De Vries, Johannes G.,Feringa, Ben L.,Janssen, Dick B.
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supporting information; experimental part
p. 2111 - 2115
(2010/11/04)
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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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- Microwave assisted fluorination: an improved method for side chain fluorination of substituted 1-arylethanones
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A two-step, one-pot microwave (MW) assisted fluorination of 1-arylethanones to their corresponding 1-aryl-2-fluoroethanones has been developed. The first step utilises Selectfluor as a fluorinating agent in methanol forming 1-aryl-2-fluoroethanones and their corresponding dimethyl acetals. In the second step, water is added and Selectfluor acts as a Lewis acid in the hydrolytic cleavage of the dimethyl acetals. Compared to the thermal synthesis, the MW assisted method leads to a reduction in reaction time both in the fluorination and for the dimethyl acetal cleavage. Moreover, the one-pot procedure reduces reagent and solvent consumption. The method is best suited for the preparation of 1-aryl-2-fluoroethanones containing substituents that deactivates electrophilic aromatic substitution, however highly electron deficient ketones such as 1-(3,5-dinitrophenyl)ethanone reacts more slowly. Reactions using electron rich aromatic ketones had a low regioselectivity, and also produced fluoroaromatic products.
- Krane Thvedt, Thor H?kon,Fuglseth, Erik,Sundby, Eirik,Hoff, B?rd Helge
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experimental part
p. 9550 - 9556
(2010/02/27)
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- Copper(I)-promoted synthesis of chloromethyl ketones from trichloromethyl carbinols
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(Chemical Equation Presented) Reaction of several trichloromethyl carbinols with 2 equiv of CuCl/bpy in refluxing DCE for 3 h afforded chloromethyl ketones in excellent yield by 1,2-H shift in the copper-chlorocarbenoid intermediate.
- Ram, Ram N.,Manoj
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p. 5633 - 5635
(2008/12/21)
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- Efficient α-chlorination and α-bromination of carbonyl compounds using N-halosuccinimides/UHP in ionic liquid
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A facile and efficient method for the α-halogenation of carbonyl compounds utilizing N-halosuccinimides (NXS) in the presence of urea-hydrogen peroxide (UHP) in [bmim]BF4 has been newly developed. Copyright Taylor & Francis Group, LLC.
- Lee, Jong Chan,Park, Hyun Jung
-
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- α-chlorination of acetophenones using 1,3-dichloro-5,5- dimethylhydantoin
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A novel method for the synthesis of α-chloroacetophenones using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) and p-toluenesulfonic acid in methanol at 30-35°C is described. Substituted acetophenones at the para position or meta position of aromatic ring give α-chloroacetophenones in high yield. However, reaction of o-nitroacetophenone does not take place under the same condition. Copyright Taylor & Francis LLC.
- Xu, Zijin,Zhang, Deyan,Zou, Xinzhuo
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p. 255 - 258
(2007/10/03)
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- Efficient microwave induced direct α-halogenation of carbonyl compounds
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A novel and direct method for the synthesis of α-halocarbonyl compounds using sequential treatment of carbonyl compounds with [hydroxy(tosyloxy)iodo]benzene followed by magnesium halides under solvent-free microwave irradiation conditions is described.
- Lee, Jong Chan,Park, Jin Young,Yoon, So Young,Bae, Yong Hun,Lee, Seung Jun
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p. 191 - 193
(2007/10/03)
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- Synthesis and fungicidal activity of 2-imino-3-(4-arylthiazol-2-yl)- thiazolidin-4-ones and their 5-arylidene derivatives
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Five derivatives of 2-imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and a series of their 5-arylidene derivatives have been synthesized and tested for antifungal activity against seven agricultural fungi. 2-Imino-3-(2,4-dichloro-5- fluorophenylthiazol-2-yl)-4-thiazolidi-none and 2-imino-3-(2,4- dichlorophenylthiazol-2-yl)-4-thiazolidione, both of them new compounds, exhibited higher fungicidal effects than the other compounds prepared.
- Liu, Hui-Ling,Li, Zongcheng,Anthonsen, Thorleif
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p. 1055 - 1061
(2007/10/03)
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- S4N4SbCl5 complex: a useful reagent for conversion of sterically less hindred α-bromo ketones to α-chloro ketones
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The reactions of sterically less hindered α-bromo alkyl and aryl ketones with tetrasulfur tetranitride antimony pentachloride (S4N4SbCl5) complex in toluene at reflux gave the corresponding α-chloro kerones in good to excellent yields.
- Kim, Kil-Joong,Kim, Kyongtae
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p. 4227 - 4230
(2007/10/03)
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- The Acidity of Weak Carbon Acids. Part 6. Acidity of p-Substituted Acetophenones in the Absence and Presence of Cyclodextrins as Determined by Rates of Chlorination by Hypochlorite
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Rate coefficients have been measured for the chlorination of a series of p-substituted acetophenones in water at several temperatures in both the absence and presence of α- and β-cyclodextrins, as well as in aqueous dioxane.The rate determining ionisation of the acetophenones is subject to catalysis by inclusion in the cyclodextrins.The effects of substitution have been assessed by means of the Hammett equation.The catalysis appears to arise from an anionic secondary hydroxy group on the cyclodextrin and a microsolvent effect on the transmission of the polar effects.
- Bowden, Keith,Nair, T. D. Radhakrishnan
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p. 1201 - 1215
(2007/10/02)
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- Carbon-13 NMR Spectra of Some 4-Substituted Phenacyl Chlorides and Iodides
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The 13C NMR signals for some 4-substituted phenacyl chlorides and iodides were assigned.The carbonyl carbons exhibit upfield shifts compared with those of the corresponding 4-substituted acethophenones; in the chlorinated derivatives a downfield shift is observed for the α-methylene carbons, while a reverse effect occurs in the iodinated compounds.The chemical shifts of the aromatic ring carbons are in close agreement with those calculated using substituent chemical shifts.KEY WORDS 13C NMR 4-substituted pheacyl chlorides and iodides
- Olivato, Paulo Roberto,Guerrero, Sandra Alvarez,Rittner, Roberto
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p. 179 - 180
(2007/10/02)
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- INVESTIGATIONS ON REACTIONS OF CHLORINE DIOXIDE AND SODIUM CHLORITE WITH ORGANIC COMPOUNDS. PART XXXV. REACTIONS OF CHLORINE DIOXIDE WITH RING-SUBSTITUTED STYRENES
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Reactions of chlorine dioxide with ring substituted styrenes (1a-n) in carbon tetrachloride at 52-54 deg C were studied.The reaction products were isolated and characterised.It has been found that methyl-, chloro-, nitrostyrenes and 4-methoxystyrene are attacked by chlorine dioxide exclusively on the vinyl group, to yield the corresponding α-chloroacetophenones (2), diastereoisomers of β-chlorostyrene (6,7), oxidation products (8,9) and some polymers.Oxidation of its phenolic hydroxyl groups and vinyl polymerization took place in hydroxystyrenes.
- Kwiecien, Halina,Jalowiczor, Jozef
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p. 811 - 824
(2007/10/02)
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- Kinetics of Oxidation of Ketones by Trichloroisocyanuric Acid in Acid Medium: Anomalous Behaviour of Alkoxyacetophenones
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Kinetics of oxidation of aliphatic, aryl aliphatic and cyclic ketones by trichloroisocyanuric acid has been studied in aqueous acetic acid medium in the presence of HClO4.The reaction is acid-catalysed exhibiting first order dependence each in and and zero order dependence in .This supports the acid catalyzed enolisation of ketone as the rate-determining step and reaction between enol and oxidant as the fast step.Alkoxyacetophenones exhibit an anomalous behaviour in that there is first order dependence on the halogenating agent.This has been attributed to the fact that in the case of alkoxyacetophenones the rates of halogenation may be less than the rates of enolisation.The decrease in dielectric constant of the medium slightly enhances the rate of reaction.The ρ? relationship in the case of acetophenones is linear with ρ as -0.2 indicating the simultaneous operation of equilibrium protonation of ketone and deprotonation of conjugate acid.Arrhenius activation parameters have been computed.A plausible mechanism consistent with the experimental results is postulated.
- Radhakrishnamurti, P. S.,Rath, Nabeen Kumar
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p. 300 - 303
(2007/10/02)
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- Chlorination of Ketones with N-Chlorosaccharin
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The kinetics of chlorination of a few typical aliphatic, alicyclic and arylalkyl ketones with N-chlorosaccharin (NCSA) have been investigated in aqueous acetic acid (50percent v/v).The reaction is first order with respect to both and , but the rate is independent of .In the case of acetone, a primary kinetic isotope effect (kH/kD) of 4.44 has been observed.There is a fractional order dependence on the initially added in the absence of mineral acids.The kinetic data have been rationalised and suitable mechanisms proposed.
- Panchatsharam, V. S.,Sundaram, S.,Venkatasubramanian, N.
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p. 469 - 472
(2007/10/02)
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- Molecular Rearrangements. 13. Kinetics and Mechanism of Rearrangements of Some Ring-Substituted α-Chlorostyrene Oxides and trans-β-Chlorostyrene Oxides.
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The synthesis of certain phenyl-substituted derivatives of the isomeric trans-β-chlorostyrene oxides (6) and α-chlorostyrene oxides (7) are reported.The kinetics of rearrangement of 6 (X = p-CH3, H, p-Br, m-Cl, p-NO2) to phenylchloroacetaldehydes (12) in CCl4 buffered by Na2HPO4 and 7 (X = p-CH3, H, p-NO2) to ω-chloroacetophenones in CCl4 were determined by following the rates of disappearance of the α-chloro epoxide and formation of the α-chloro carbonyl product.These substituent effects at 130 deg C were correlated with ?+ constants, yielding ρ values of-3.5 and -0.57 for the rearrangements of 6 and 7, respectively.In nitrobenzene solvent, the kC6H5NO2/kCCl4 for 6 was 180 and for 7 was 1740, the latter solvent effect attributed to nucleophilic solvent participation.It was concluded that these thermal rearrangements of 6 and 7 occur by disrotatory Cβ-O bond heterolysis to yield the corresponding α-keto carbonium-chloride ion pairs.
- McDonald, Richard N.,Cousins, Raymond C.
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p. 2976 - 2984
(2007/10/02)
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