- Nickel(II)- And Silver(I)-Catalyzed C-H Bond Halogenation of Anilides and Carbamates
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ortho -C-H bond halogenation of anilides and N -aryl carbamates using easily available N -halosuccinimides (NXS) as the active halogenation reagent in the presence of nickel or silver catalyst has been developed. This method provides a new approach to 2-haloanilides and carbamates, which may serve as starting materials for the synthesis of pharmaceutically and biologically active compounds.
- Kianmehr, Ebrahim,Afaridoun, Hadi
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p. 1513 - 1523
(2020/12/14)
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- A Visible Light-Mediated Regioselective Halogenation of Anilides and Quinolines by Using a Heterogeneous Cu-MnO Catalyst
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A simple and practical heterogeneous Cu-MnO catalyzed regioselective halogenation of anilides and quinolines under irradiation with household 40 W incandescent lamp was developed. This method uses a recyclable Cu-MnO catalyst, acetonitrile as an industrially friendly solvent, and economic N-halo succinimides as a halogenating source. The reaction is scalable and well tolerated with a broad range of functional groups.
- Singh, Harshvardhan,Sen, Chiranjit,Sahoo, Tapan,Ghosh, Subhash Chandra
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p. 4748 - 4753
(2018/09/06)
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- Cobalt(II)-catalyzed regioselective C-H halogenation of anilides
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A cobalt-catalyzed regioselective C-H halogenation methodology is reported herein. The highlight of this work is the highly selective C-H functionalization of anilides, which results in high-yielding, versatile, and practical halogenated products. Thereby, brominations, chlorinations and iodinations of many electron-rich and electron-deficient anilides were achieved in a highly selective fashion. Mechanistic studies with respect to the pathway of the reaction are also described.
- Li, Ze-lin,Sun, Kang-kang,Cai, Chun
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supporting information
p. 5433 - 5440
(2018/08/12)
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- A para-C–H Functionalization of Aniline Derivatives via In situ Generated Bulky Hypervalent Iodinium Reagents
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A practical para-C-H functionalization of aniline derivatives has been developed using an in situ generated bulky hypervalent iodinium reagent. Para-iodo, bromo, chloro, nitro, trifluormethyl aniline derivatives can be obtained efficiently, in many cases in 10 min in a transition metal-free manner. Medicinal chemicals or intermediates can be purified without column chromatography or recrystallization, which significantly reduces the waste and simplifies the work-up process.
- Tian, Chao,Yao, Xu,Ji, Weizhe,Wang, Qian,An, Guanghui,Li, Guangming
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supporting information
p. 5972 - 5979
(2018/11/23)
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- Monoprotected l-Amino Acid (l-MPAA), Accelerated Bromination, Chlorination, and Iodination of C(sp2)?H Bonds by Iridium(III) Catalysis
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Halogenated arenes are important structural motifs commonly found in biologically active molecules and used for a variety of transformations in organic synthesis. Herein, we report the mono-protected l-amino acid (l-MPAA) accelerated iridium(III)-catalyzed halogenation of (hetero)anilides at room temperature. This reaction constitutes the first example of an iridium(III)/l-MPAA-catalyzed general halogenation of (hetero)arenes through C(sp2)?H activation. Furthermore, we demonstrate the potential utility of our method through its use in the synthesis of a quinolone derivative.
- Kathiravan, Subban,Nicholls, Ian A.
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supporting information
p. 7031 - 7036
(2017/05/29)
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- Synthesis of 2-methylbenzoxazoles directly from: N -phenylacetamides catalyzed by palladium acetate
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A method to synthesize 2-methylbenzoxazoles directly from N-phenylacetamides catalyzed by Pd(OAc)2 in the presence of K2S2O8 and TfOH has been developed. The desired products were obtained in moderate to excellent yields. This approach provides a facile procedure to prepare benzoxazoles with available substrates. It is found that TfOH is the key factor for this cyclization reaction. A plausible mechanism of the reaction is proposed according to the control reactions and the literature.
- Wang, Biying,Jiang, Chengfei,Qian, Jiasheng,Zhang, Shuwei,Jia, Xiaodong,Yuan, Yu
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p. 101 - 107
(2017/12/27)
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- Regioselective and efficient bromination of anilides on water using HBr and Selectfluor
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A metal-, additive-, and Br2-free highly regioselective bromination of anilides using HBr and Selectfluor is presented. This reaction proceeded under mild conditions with high efficiency and good functional group tolerance, and water served as the solvent. In general, with substrates bearing no para-substituent, para-mono-bromination occurred exclusively, while ortho-mono-brominated anilides were the only products when para-positions were blocked. The incorporation of a stronger orienting group might result in a reversed regioselectivity, and the reaction was sensitive to steric hindrance.
- Liang, Deqiang,Li, Xiangguang,Wang, Chaowu,Dong, Qishan,Wang, Baoling,Wang, Hai
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supporting information
p. 5390 - 5394
(2016/11/11)
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- Bromination of arenes using I2O5-KBr in water
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An efficient and environmentally benign bromination of various aromatic compounds using aN aqueous I2O5-KBr system at room temperature has been developed in this work. A series of aromatic compounds such as acetophenones, benzaldehydes, benzoic acids, anilines, amides, and aminopyridine have been successfully brominated in excellent regioselectivities and good yields under the typical reaction conditions. The features of KBr as brominating reagent, water as solvent, and mild conditions make this system an attractive synthetic procedure. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Hou, Jieping,Li, Zejiang,Jia, Xiao-Dong,Liu, Zhong-Quan
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supporting information
p. 181 - 187
(2013/12/04)
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- Air oxidation of N-cyclopropylanilines
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Air oxidation of N-cyclopropylanilines was shown to occur under either ambient conditions or accelerated conditions (warming or shining light) in an open container. A subsequent fragmentation resulted in formation of the corresponding acetamide. While potential mechanisms have been previously proposed, simple aerobic oxidation to β-hydroxy-propionamides in the absence of a radical promoter has not been previously reported. Copyright Taylor & Francis Group, LLC.
- Blackburn, Anthony,Bowles, Daniel M.,Curran, Timothy T.,Kim, Hui
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p. 1855 - 1863
(2012/04/10)
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- Mild C - H halogenation of anilides and the isolation of an unusual palladium(I)-palladium(II) species
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Reducing the load: A facile palladium-catalyzed ortho-selective bromination and chlorination of anilides occurs under aerobic conditions at room temperature when N-halosuccinimides (NXS) are used in the presence of p-toluenesulfonic acid (PTSA). The orthopalladated PTSA complex is not only catalytically competent but also undergoes a reductive process to yield an unusual PdI-PdII tetramer (see structure; Pdgreen, Ored, Syellow, Cgray). Copyright
- Bedford, Robin B.,Haddow, Mairi F.,Mitchell, Charlotte J.,Webster, Ruth L.
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supporting information; experimental part
p. 5524 - 5527
(2011/07/31)
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- Solvent-free aromatic C-H functionalisation/halogenation reactions
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The solvent-free, palladium-catalysed reaction of anilides with CuCl 2 in the presence or absence of copper acetate yields ortho-chlorinated anilides in good to excellent yields, even on a large scale (100 mmol). By contrast, the equivalent reactions with copper bromide, either solvent free or in 1,2-dichloroethane, in the presence or absence of palladium, under air or inert conditions, gave the products of simple electrophilic bromination. Mechanistic studies highlighted the involvement of palladacyclic intermediates, one of which was characterised crystallographically, which undergo subsequent reaction with copper(ii) chloride to yield the chlorinated anilide products.
- Bedford, Robin B.,Engelhart, Jens U.,Haddow, Mairi F.,Mitchell, Charlotte J.,Webster, Ruth L.
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experimental part
p. 10464 - 10472
(2011/01/05)
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- Chemoselective bromination in a two-step substitution under the influence of tetrachlorosilane and N-bromosuccinimide
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The synthesis of gem dibromide carbonyl compounds via a cheep and readily available combined reagent from tetrachlorosilane and N-bromosuccinimide (TCS-NBS). Copyright Taylor & Francis Group, LLC.
- Elmorsy, Saad,Badawy, Doria,Khatab, Tamer
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p. 2005 - 2012
(2007/10/03)
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- Effect of cyclodextrins on electrophilic aromatic bromination in aqueous solution
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Cyclodextrins act as molecular reactors to change the ratios of the products of reactions of anisole, acetanilide, 3-methylanisole, and 3-methylacetanilide with pyridinium dichlorobromate. With anisole and acetanilide, bromination at the para position is favoured over ortho substitution, and the effect is greatest with α-cyclodextrin. In the reactions of the methylanisole and methylacetanilide, the cyclodextrins afford higher yields of monobrominated products and less of the di- and tribromides, and β-cyclodextrin has the greatest effect. These outcomes can be attributed to inclusion of the substrates within the cyclodextrins restricting access of the reagent adjacent to the methoxy and acetamido groups. The yields of 4-bromoanisole, 4-bromoacetanilide, 4-bromo-3-methylanisole, and 4-bromo-3-methylacetanilide are thus increased from 73 to 94, 55 to 98, 37 to 86, and 39 to 72%, respectively. Perhaps more significantly, the quantities of the corresponding by-products are substantially reduced, from 27 to 6, 45 to 2, 63 to 14, and 61 to 28%. Since the reactions occur readily in water at ambient temperature, the cyclodextrins make them very efficient.
- Dumanski, Paul G.,Easton, Christopher J.,Lincoln, Stephen F.,Simpson, Jamie S.
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p. 1107 - 1111
(2007/10/03)
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- Oxidation of benzyl alcohols with Oxone and sodium bromide
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Reaction of benzyl alcohols with Oxone and sodium bromide in aqueous acetonitrile gave the corresponding benzaldehydes in excellent yields. However, electron-rich benzyl alcohols afforded ring bromination products via bromodecarbonylation of the resulting benzaldehydes.
- Koo, Bon-Suk,Lee, Chang Keun,Lee, Kee-Jung
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p. 2115 - 2123
(2007/10/03)
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- Bromodecarbonylation and bromodecarboxylation of electron-rich benzaldehydes and benzoic acids with oxone and sodium bromide
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Benzaldehydes and benzoic acids bearing ortho- and paraelectron donating substituents having unshared electron-pair have undergone bromodecarbonylation or bromodecarboxylation on treatment with sodium bromide in the presence of Oxone in aqueous methanol.
- Koo, Bon-Suk,Kim, Eun-Hoo,Lee, Kee-Jung
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p. 2275 - 2286
(2007/10/03)
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- Heterocyclic Systems Containing Bridgehead Nitrogen Atom: Part LXII - Synthesis of Thiazolobenzimidazol-3(2H)-ones
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2,4-Dibromo-6-nitroaniline (Ia), on reduction with Raney nickel and hydrazine hydrate followed by treatment of the resulting diamine with carbon disulfide in situ gives 4,6-dibromo-2-mercaptobenzimidazole (IIa).Compound (IIa) on reaction with chloroacetic
- Sharma, B. R.,Pujari, H. K.
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p. 121 - 127
(2007/10/02)
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- Kinetics of Bromination of Acetanilide and Some Substituted Acetanilides by N-Bromoacetamide
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Bromination of acetanilide and p-methyl-, p-chloro-, p-bromo- and p-nitro-acetanilides by N-bromoacetamide (NBA) in aqueous perchloric acid medium is first order in and fractional order in .The reaction is acid-catalysed with first order dependence in .The effects of varying ionic strength and dielectric constant of the solvent mixture are marginal.Added Cl(-) and Br(-) ions have a pronounced catalytic effect.A mechanism involving the formation of a N-halo intermediate followed by Orton rearrangement has been postulated.
- Murti, P. S. Radhakrishna,Sasmal, B. M.,Patnaik, D. P.
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p. 948 - 949
(2007/10/02)
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