- 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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- Electrochemical Oxidative Functionalization of Arylalkynes: Access to α,α-Dibromo Aryl Ketones
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A general and effective protocol to synthesize α,α-dibromo aryl ketones has been developed via an electrochemical oxidative method. The reaction proceeds smoothly at room temperature in an undivided cell without the addition of external oxidants. In the reaction process, LiBr acts as both bromine source and supporting electrolyte. This electrooxidation strategy has good substrate applicability and functional group compatibility. Moreover, the reaction could be scaled up efficiently in a continuous flow cell. The target product could undergo further functionalization for the synthesis of some useful heterocyclic compounds. (Figure presented.).
- Wang, Dan,Wan, Zhaohua,Zhang, Heng,Lei, Aiwen
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supporting information
p. 1022 - 1027
(2020/12/31)
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- Selective Debromination of α,α,α-Tribromomethylketones with HBr–H2O Reductive Catalytic System
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A debromination of α,α,α-tribromomethylketones is developed for chemoselective synthesis of α-mono- and α,α-dibromomethylketones with high selectivity under H2O–HBr reductive conditions. This method offers an efficient and direct way to synthesize α-mono or α,α-dibromomethylketone compounds in high to excellent yields through the process of HBr self-circulation in water.
- Cheng, Zhao,Guo, Hongmei,Huang, Guozheng,Rexit, Abulikemu Abudu,Wang, Hui,Zheng, Meng-Xia
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p. 6455 - 6458
(2020/10/21)
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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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- α,α-Dibromoketone precursors in the synthesis of some new thiazole derivatives: Thiazol-2-yl hydrazonobutanoates, thiazol-2-yl pyrazole-4-carboxylates and acids
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In the present study, α,α-dibromoacetophenones are used as efficient precursors for the facile synthesis of several new hydrazonothiazoles, ethyl 3-((4-arylthiazol-2-yl)hydrazono)butanoates, which undergo Vilsmeier-Haack cyclization to obtain thiazolylpyrazole esters, ethyl 3-methyl-1-(4-arylthiazol-2-yl)-1H-pyrazole-4-carbxylates, basic hydrolysis of which gives the corresponding acids, 3-methyl-1-(4-arylthiazol-2-yl)-1H-pyrazole-4-carbxylic acids. All these compounds are tested for antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis; Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa and antifungal activity against Saccharomyces cerevisiae and Candida albicans.
- Joshi, Radhika,Kiran, Vijay,Pundeer, Rashmi
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supporting information
(2020/03/04)
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- Carbonyl dibromo compound, as well as preparation method and application thereof
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The invention belongs to the technical field of synthetic chemistry, and discloses a carbonyl dibromo compound, as well as a preparation method and an application thereof. The carbonyl dibromo compound has a chemical structural general formula as shown in the specification, wherein R is aryl, substituted aryl, heteroaryl, substituted heteroaryl, paraffin, substituted alkyl or silicyl, wherein thesubstituent group of the substituted aryl, substituted heteroaryl and substituted alkyl is more than one of halogen, alkyl, halogenated alkyl, alkoxy, nitryl, hydroxy, cyan, ester, carbonyl or amide;the heteroaryl is an aromatic ring containing nitrogen, oxygen or sulfur or derivatives thereof. According to the carbonyl dibromo compound, an alkyne compound and sodium bromide are used as raw materials, a high-iodine reagent is used as a catalyst and oxidant, the carbonyl dibromo compound is generated from the alkyne compound. The method has the advantages of mild reaction condition, no heatingrequirement, simple operation steps, high selectivity and high yield, and is safe, reliable and environment-friendly.
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-
Paragraph 0038-0040
(2019/03/08)
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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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- Highly efficient recyclable sol gel polymer catalyzed one pot difunctionalization of alkynes
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Amino-bridged gel polymer P1 was discovered to catalyze alkyne halo-functionalization in excellent yields, regioselectivity, functional group compatibility, and recyclability. We have observed that both aromatic and aliphatic alkynes can be converted to α,α-dihalogenated ketones in the presence of polymer P1 under metal-free conditions at room temperature within a short reaction time.
- Domena, Justin,Chong, Carlos,Johnson, Qiaxian R.,Chauhan, Bhanu P. S.,Xing, Yalan
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supporting information
(2018/08/17)
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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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- Directing group assisted copper-mediated aroylation of phenols using 2-bromoacetophenones
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A new directing group assisted method for the synthesis of aryl esters is described. In this Cu(ii)-mediated reaction, 2-formylphenols and 2-acetylphenols are easily converted into aryl esters via treatment with a new aroylating agent 2-bromoacetophenone.
- Baruah, Swagata,Borthakur, Somadrita,Gogoi, Sanjib
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supporting information
p. 9133 - 9135
(2017/08/17)
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- One-pot syntheses of α,α-dibromoacetophenones from aromatic alkenes with 1,3-dibromo-5,5-dimethylhydantoin
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A novel method for the preparation of α,α-dibromoacetophenones from aromatic alkenes was reported. This procedure was mediated by 1,3-dibromo-5,5-dimethylhydantoin, which served as bifunctional reagent, proceeding oxidation and bromination in one-pot.
- Wu, Ping,Xu, Senhan,Xu, Hao,Hu, Haiyan,Zhang, Wei
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supporting information
p. 618 - 621
(2017/01/25)
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- Water-controlled selective preparation of α-mono or α,α′-dihalo ketones: Via catalytic cascade reaction of unactivated alkynes with 1,3-dihalo-5,5-dimethylhydantoin
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The control of a reaction that can produce multiple products from the same starting material is a highly attractive and challenging concept in organic synthesis. An efficient protocol for the selective synthesis of α-mono or α,α′-dihalo ketones via a water-controlled three-component thiourea-catalyzed cascade reaction of unactivated alkynes, 1,3-dihalo-5,5-dimethylhydantoin and water has been developed. α-Monohaloketones were obtained in aqueous acetone at 45 °C; conversely, α,α′-dihalo ketones were formed with pure water as the sole solvent at room temperature.
- Wu, Chao,Xin, Xiu,Fu, Zhi-Min,Xie, Long-Yong,Liu, Kai-Jian,Wang, Zheng,Li, Wenyi,Yuan, Zhi-Hui,He, Wei-Min
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p. 1983 - 1989
(2017/06/09)
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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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- CoFe2O4–SiO2–SO3H nanocomposite as a magnetically recoverable catalyst for oxidative bromination of alkynes
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A hybrid catalyst has been prepared by incorporating sulfonic acid onto cobalt ferrite magnetic nanoparticles. The catalyst was successfully applied for rapid (20 min) synthesis of α,α-dibromoketones directly from alkynes and NBS. The reaction works well in the presence of 10 wt% of the catalyst at room temperature to produce the desired products in high yield. The catalyst could be recovered using an external magnet and reused without appreciable change in activity.
- Dutta, Mintu Maan,Rajbongshi, Kamal Krishna,Phukan, Prodeep
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p. 2330 - 2341
(2017/11/15)
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- TsNBr2mediated oxidative functionalization of alkynes
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A new approach has been developed for oxidative transformation of alkynes by controlled manipulation of TsNBr2mediated process. Alkynes could be readily converted to ketones and α-bromoketones via an oxybromination–debromination sequence. When alkynes are treated successively with TsNBr2, KI and Na2SO3in a mixture of acetone and water at room temperature, corresponding ketones were obtained. On the other hand, treatment of alkynes with TsNBr2and Na2SO3in a mixture of ethyl acetate, acetone and water at room temperature could produce corresponding α-bromoketones. 1-Bromoalkynes could also be synthesized from corresponding alkynes within a very short time using TsNBr2at room temperature. In all cases, excellent yields of corresponding products are obtained.
- Rajbongshi, Kamal Krishna,Hazarika, Debojit,Phukan, Prodeep
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p. 4151 - 4158
(2016/07/06)
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- α,α-dibromoketones as useful precursors in organic synthesis: A simple and efficient synthesis of 2,4-diaryl- 1,2,3-triazoles via oxidative cyclization of bisphenylhydrazones
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α,α-Dibromoacetophenones (1a-1f) on reaction with phenylhydrazine afford corresponding arylglyoxal bisphenylhydrazones (2a-2f). The oxidation of bishydrazones 2a-2f by using copper(II) chloride in acetic acid leads to intramolecular cyclization with the formation of 2,4-diaryl-1,2,3-triazoles (3a-3f). The method for the conversion 1 → 3 has been simplified by developing one-pot procedure without isolation of intermediates 2.
- Arora, Loveena,Sharma, Nisha,Kapoor, Jitander K.
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p. 291 - 296
(2019/01/18)
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- Continuous flow chemistry: A discovery tool for new chemical reactivity patterns
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Continuous flow chemistry as a process intensification tool is well known. However, its ability to enable chemists to perform reactions which are not possible in batch is less well studied or understood. Here we present an example, where a new reactivity pattern and extended reaction scope has been achieved by transferring a reaction from batch mode to flow. This new reactivity can be explained by suppressing back mixing and precise control of temperature in a flow reactor set up. This journal is the Partner Organisations 2014.
- Hartwig, Jan,Metternich, Jan B.,Nikbin, Nikzad,Kirschning, Andreas,Ley, Steven V.
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supporting information
p. 3611 - 3615
(2014/06/09)
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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 tandem one-pot aqueous phase synthesis of thiazoles/selenazoles
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The first ever tandem one-pot synthetic protocol for the synthesis of thiazoles/selenazoles from alkynes via the formation of 2,2-dibromo-1- phenylethanone is reported. The reaction is catalyzed by β-cyclodextrin in aqueous medium and resulted in good yields.
- Madhav,Narayana Murthy,Anil Kumar,Ramesh,Nageswar
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experimental part
p. 3835 - 3838
(2012/08/14)
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- A facile one-pot synthesis of α-halo,α-allylic aldehydes from α,α-dihalo ketones utilizing allylic zinc bromide
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An efficient synthesis of various α-halo,α-allylic aldehydes from α,α-dihalo ketones using both cyclic (3-bromocyclohex-1-ene zinc bromide and (Z)-3-bromocyclobut-1-ene zinc bromide) and acyclic (allylzinc bromide and cinnamylzinc bromide) type of allylic organozinc bromide with DMF as base is described. A possible reaction mechanism is also proposed. Copyright
- Wang, Xiaolei,Zhang, Songlin
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experimental part
p. 96 - 102
(2012/03/10)
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- A facile synthesis of two series of multifunctional carbon compounds from α,α-dihalo ketones using allylsamarium bromide
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The use of allylsamarium bromide to effect two different reactions on the common starting material, a,a-dihalo ketones, is presented. With DMF, α-halo-α-allyl aldehydes were obtained, while α-hydroxy- α-allyl aldehyde acetals were obtained in the presence of NaOMe/MeOH. Georg Thieme Verlag Stuttgart.
- Liu, Xiaodan,Zhang, Songlin,Di, Jucai
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experimental part
p. 2749 - 2755
(2010/01/21)
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- A facile one-pot synthesis of a?-halo-a?-allyl-aldehydes from a?,a?-Dihaloketoncs Using Allylsamarium Bromide and DMF
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A convenient, one-pot synthesis of a range of a?-halo-a?-allyl aldehydes is described. The protocol involves the reaction of allylsamarium bromide with various a?,a?-dihalo ketones. A possible mechanism of the transformation is proposed.
- Di, Jucai,Zhang, Songlin
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experimental part
p. 1491 - 1494
(2009/04/07)
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- TMS·OTf-Catalyzed α-bromination of carbonyl compounds by N-bromosuccinimide
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Various carbonyl compounds undergo α-bromination reaction under a mild and practical condition utilizing N-bromosuccinimide (NBS), catalyzed by trimethylsilyl trifluoromethanesulfonate (TMS·OTf). This method is also effective for the side-chain bromination of heteroaromatic carbonyl compounds without the ring brominations.
- Guha, Samar Kumar,Wu, Bo,Kim, Beom Soo,Baik, Woonphil,Koo, Sangho
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p. 291 - 293
(2007/10/03)
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- Microwave-induced selective synthesis of α-bromo and α,α-dibromoalkanones using dioxane-dibromide and silica gel under solvent-free conditions
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Selective synthesis of α-bromo and α,α-dibromoalkanones using dioxane-dibromide and silica gel in solvent-free conditions under microwave irradiation has been reported. The amount of dioxane-dibromide, silica gel and time of irradiation are keys for the selective synthesis of α-bromo and α,α-dibromoalkanones.
- Paul, Satya,Gupta, Varinder,Gupta, Rajive,Loupy, André
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p. 439 - 442
(2007/10/03)
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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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