- Access to α,α-dihaloacetophenones through anodic C[dbnd]C bond cleavage in enaminones
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We have developed a method to synthesize α,α-dihaloketones under electrochemical conditions. In this reaction, the Cl- or Br- is oxidized to Cl2 or Br2 at the anode, which undergoes two-step addition reactions with the N,N-dimethyl enaminone, and finally breaks C[dbnd]C of the N,N-dimethyl enaminone to generate α,α-dihaloketones. The electrosynthesis reaction can be conveniently carried out in an undivided electrolytic cell at room temperature. In addition, various functional groups are compatible with this green protocol which can be applied simultaneously to the gram scale without significantly lower yield.
- Zhang, Zhenlei,Yang, Jiusi,Wu, Kairui,Yu, Renjie,Bu, Jiping,Huang, Zijun,Li, Shaoke,Ma, Xiantao
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supporting information
(2021/12/20)
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- Switchable Synthesis of α,α-Dihalomethyl and α,α,α-Trihalomethyl Ketones by Metal-Free Decomposition of Enaminone C=C Double Bond
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The novel free radical-based cleavage of the enaminone C=C double bond is realized by using N-halosuccinimides (NXS) in the presence of benzoyl peroxide (BPO) with mild heating, enabling the tunable synthesis of α,α-dihalomethyl ketones and α,α,α-trihalomethyl ketones under different reaction conditions. The formation of these divergent products involving featured C=C double bond cleavage requires no any metal reagent, and represents one more practical example on the synthesis of poly halogenated methyl ketones via the functionalization of carbon?carbon bond. (Figure presented.).
- Liu, Yunyun,Xiong, Jin,Wei, Li,Wan, Jie-Ping
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supporting information
p. 877 - 883
(2020/01/24)
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- Electrochemical synthesis of α,α-dihaloacetophenones from terminal alkyne derivatives
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By virtue of electrochemistry, a series of α,α-dihaloacetophenones were easily obtained with good to excellent yields. This electrochemical procedure was taken in a divided cell with constant current in aqueous media. The reaction can be carried out smoothly at room temperature under metal and oxidant free condition, which provides an eco-friendly synthesis for the α,α-dihaloacetophenone derivatives.
- Li, Zhibin,Sun, Qi,Qian, Peng,Hu, Kangfei,Zha, Zhenggen,Wang, Zhiyong
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supporting information
p. 1855 - 1858
(2020/03/10)
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- Electrochemical Oxidative Oxydihalogenation of Alkynes for the Synthesis of α,α-Dihaloketones
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An electrochemical oxydihalogenation of alkynes has been developed for the first time. Using this sustainable protocol, a variety of α,α-dihaloketones can be prepared with readily available CHCl3, CH2Cl2, ClCH2CH2Cl, and CH2Br2 as the halogen source under electrochemical conditions at room temperature.
- Meng, Xiangtai,Zhang, Yu,Luo, Jinyue,Wang, Fei,Cao, Xiaoji,Huang, Shenlin
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supporting information
p. 1169 - 1174
(2020/02/04)
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- Visible-light-promoted oxidative halogenation of alkynes
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In nature, halogenation promotes the biological activity of secondary metabolites, especially geminal dihalogenation. Related natural molecules have been studied for decades. In recent years, their diversified vital activities have been explored for treating various diseases, which call for efficient and divergent synthetic strategies to facilitate drug discovery. Here we report a catalyst-free oxidative halogenation achieved under ambient conditions (halide ion, air, water, visible light, room temperature, and normal pressure). Constitutionally, electron transfer between the oxygen and halide ion is shuttled via simple conjugated molecules, in which phenylacetylene works as both reactant and catalyst. Synthetically, it provides a highly compatible late-stage transformation strategy to build up dihaloacetophenones (DHAPs).
- Li, Yiming,Mou, Tao,Lu, Lingling,Jiang, Xuefeng
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supporting information
p. 14299 - 14302
(2019/12/02)
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- Micelle-Enabled Photoassisted Selective Oxyhalogenation of Alkynes in Water under Mild Conditions
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Using micelles of FI-750-M, visible light, photocatalysts, and inexpensive halogenating reagents, such as N-bromosuccinimide and N-chlorosuccinimde, selective oxyhalogenations of alkynes were achieved in water under very mild conditions. No halogenation at the aromatic rings was detected, and control experiments revealed the radical pathway. The easily conducted protocol exhibited high reproducibility, was readily adjusted to gram scale, and allowed for recycling of reaction medium and catalyst.
- Finck, Lucie,Brals, Jeremy,Pavuluri, Bhavana,Gallou, Fabrice,Handa, Sachin
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p. 7366 - 7372
(2018/07/29)
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- Ultrasound-assisted tandem reaction of alkynes and trihaloisocyanuric acids by thiourea as catalyst in water
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With water as the sole solvent, a green and efficient method has been developed for the synthesis of various α,α-dihaloketones via ultrasound assisted p-tolylthiourea catalyzed tandem reaction of alkynes with trihaloisocyanuric acids. This synthetic route
- Zhang, Xingyu,Wu, Yundong,Zhang, Ya,Liu, Huilan,Xie, Ziyu,Fu, Shengmin,Liu, Fang
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p. 4513 - 4518
(2017/07/10)
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- 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
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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.).
- Tang, Shi-Zhong,Zhao, Wenshuang,Chen, Tao,Liu, Yang,Zhang, Xiao-Ming,Zhang, Fu-Min
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supporting information
p. 4177 - 4183
(2017/12/18)
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- N-Chloro-N-methoxybenzenesulfonamide: A Chlorinating Reagent
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A structurally simple and reactive chlorinating reagent, N-chloro-N-methoxybenzenesulfonamide, was conveniently and economically prepared in high yield. 1,3-Diketones, β-keto esters, benzoyl trifluoroacetones, phenols, anisoles, heteroarenes, and aromatic amines were successfully chlorinated, and the products were obtained in good to high yields.
- Pu, Xiaoqiu,Li, Qingwei,Lu, Zehai,Yang, Xianjin
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supporting information
p. 5937 - 5940
(2016/12/26)
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- K 2S 2O 8-mediated difunctionalization of C≡C bonds in water: A simple and efficient approach to α, α -dihaloacetophenones from phenylacetylenes and NaX
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A novel K2S2O8-mediated oxy-1,1-dihalogenation of alkynes with NaX in the presence of water has been developed, affording α,α-dihaloacetophenones in moderate to good yields. The advantages of this reaction are mild reaction conditions, operational simplicity, and use of pure water as reaction medium. A plausible reaction mechanism is proposed on the basis of mechanistic studies.
- Wang, Jing-Yu,Jiang, Qing,Guo, Can-Cheng
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supporting information
p. 3130 - 3138
(2015/10/12)
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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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- 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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- Cu(OTf)2-catalyzed α-halogenation of ketones with 1,3-dichloro-5,5'-dimethylhydantoin and N-bromosuccinimide
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Copper(II) triflate catalyses efficiently the α-halogentaion of aryl or alkyl ketones with l.3-diehloro-5.5'-dimethylhydantoin and N-bromosuccinimde to give the corresponding α,α-dichloroketones and α-bromoketones in high yield with excellent product selectivity.
- Jagdale, Arun R.,Chouthaiwale, Pandurang V.,Sudalai, Arumugam
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experimental part
p. 1424 - 1430
(2010/02/28)
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- A convenient and efficient synthesis of 1-aryl-2,2-dichloroethanones
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1-Arylethanones are readily chlorinated with an aqueous HCl-H 2O2 system using ethanol as a cosolvent. The reaction prceeds rapidly and results in selective conversion of 1-arylethanones into 1-aryl-2,2-dichloroethanones in yields of 48-89%, depending on the nature of the substituent in the aryl group.
- Terent'ev, Alexander O.,Khodykin, Sergey V.,Troitskii, Nikolay A.,Ogibin, Yuri N.,Nikishin, Gennady I.
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p. 2845 - 2848
(2007/10/03)
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- Phenyl-propargylether derivatives
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The invention relates to phenyl-propargylether derivatives of the general formula I including the optical isomers thereof and mixtures of such isomers, wherein R1is hydrogen, alkyl, cycloalkyl or optionally substituted aryl, R2and R3are each independently hydrogen or alkyl, R4is alkyl, alkenyl or alkynyl, R5, R6, R7, and R8are each independently hydrogen or alkyl, R9is hydrogen, optionally substituted alkyl, optionally substituted alkenyl or optionally substituted alkynyl, R10is optionally substituted aryl or optionally substituted heteroaryl, and Z is halogen, optionally substituted aryloxy, optionally substituted alkoxy, optionally substituted alkenyloxy, optionally substituted alkynyloxy, optionally substituted arylthio, optionally substituted alkylthio, optionally substituted alkenylthio; optionally substituted alkynylthio, optionally substituted alkylsulfinyl, optionally substituted alkenylsulfinyl, optionally substituted alkynylsulfinyl, optionally substituted alkylsulfonyl, optionally substituted alkenylsulfonyl or optionally substituted alkynylsulfonyl. These compounds possess useful plant protecting properties and may advantageously be employed in agricultural practice for controlling or preventing the infestation of plants by phytopathogenic microorganisms, especially fungi.
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Page column 25
(2010/02/05)
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- Reactions of 1-aryl-2,2-dihalogenoethanone oximes with tetrasulfur tetranitride (S4N4): A general method for the synthesis of 3-aryl-4-halogeno-1,2,5-thiadiazoles
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1-Aryl-2,2-dichloro-7, 1-aryl-2,2-dibromo-8, 1-aryl-2-bromo-2-fluoro-9 and 1-aryl-2-chloro-2-fluoroethanone oximes 10 have been prepared by allowing the corresponding ketones to react with hydroxylamine hydrochloride in EtOH at room temperature. Stereoche
- Yoon, Sung Cheol,Cho, Jaeeock,Kim, Kyongtae
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p. 109 - 116
(2007/10/03)
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- A Convenient Halogenation Procedure for the Preparation of α-Halocarbonyl Compounds
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Except for substituted acetophenones (p-Y-C6H4COCH3, Y=H, Br, CH3O), simple ketones, α-ketoesters and 1,3-diketones reacted smoothly with a preformed homogeneous mixture of hydrochloric acid and potassium permanganate in acetonitrile to give moderate to good yields of the corresponding α-chlorocarbonyl compounds.Mixtures of α-chloro- and α,α-dichlorocarbonyl compounds were obtained for substituted acetophenones.Brominations proceeded similarly with higher yields when the hydrochloric acid was replaced with hydrobromic acid. - Key words: α-chlorocarbonyl compounds; α-bromocarbonyl compounds; potassium permanganate; chlorination; bromination.
- Cheng, Sheng-Fan,Lin, Ching-Shan,Liu, Lilian Kao
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p. 309 - 312
(2007/10/03)
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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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- REACTION DE L'ACIDE PERCHLORIQUE SUR LES PHENYLACETYLENES SUBSTITUES. MISE EN EVIDENCE D'UN MECANISME IONIQUE ET RADICALAIRE
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We have studied the reaction of perchloric acid in acetic acid medium on some substituted phenylacetylenes.The ionic and radicalar mechanism is in agreement with the formation of and alkenyl perchlorate which is decomposed according to an homolytic process.
- Montheard, Jean-Pierre,Camps, Marcel,Benzaid, Ahmed,Pascal, Jean-Louis
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p. 3483 - 3486
(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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