Gold‐Catalyzed Halogenation of Aromatics by <i>N</i>‐Halosuccinimides

Mo, Fanyang; Yan, Jerry Mingtao; Qiu, Di; Li, Fēi; Zhang, Yan; Wang, Jianbo

doi:10.1002/anie.200906699

Cited by 236 publications

(108 citation statements)

References 62 publications

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“…can activate aromatic rings through the aryl-Ag intermediates. At the same time, the activation of NBS by acid was studied extensively, and a dual activation of both aromatic rings and NXS by Au was proposed recently [17,28]. A dual activation mechanism was proposed for the bromination of aromatic rings by the Ag/HMB (Scheme 2).…”

Section: Bromination Of P-xylene With Nbs In Dcementioning

confidence: 97%

“…The bromination of p-xylene gave 2,5-dimethylbromobenzene in excellent yield with NBS in DCE solution at 60°C (96%, Table 1, entry 3), and no benzyl bromide byproduct formed. Acetonitrile was a good solvent also for the [17], Au/HMB was tested also for the model reactions, and 2,5-dimethylbromobenzene was obtained in lower yield (Table 1, entry 12). The Ag/ HMB was recovered easily by filtration, and no Ag was detected in the filtrate analyzed by ICP-OES (below the detection limit 7 ppb).…”

Section: Bromination Of P-xylene With Nbs In Dcementioning

confidence: 99%

“…Moreover, harsh experimental conditions were required for the bromination of deactivated aromatics, such as high temperature and high acidic solutions [11,12]. Recently, efficient catalyst systems were reported for the bromination reactions under mild conditions, but high catalyst loading required, and only electron-rich aromatics were applicable [13][14][15][16][17]. Thereafter, the development of green and efficient catalysts for the bromination of aromatics remains important.…”

Section: Introductionmentioning

confidence: 98%

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Silver Catalyzed Bromination of Aromatics with N-bromosuccinimide

et al. 2012

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Section: Bromination Of P-xylene With Nbs In Dcementioning

confidence: 97%

Section: Bromination Of P-xylene With Nbs In Dcementioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Silver Catalyzed Bromination of Aromatics with N-bromosuccinimide

et al. 2012

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“…To overcome these problems we developed a strategy based on the aromatic iodination of blebbistatin followed by a halogen azide exchange step (17)(18)(19)(20)(21)(22). Iodination of blebbistatin was performed using N-iodosuccinimide and was catalyzed by the super acid boron trifluoride dihydrate, which was also the main solvent of the reaction (Fig.…”

Section: Resultsmentioning

confidence: 99%

Azidoblebbistatin, a photoreactive myosin inhibitor

Képiró¹,

Várkuti²,

Bodor³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Photoreactive compounds are important tools in life sciences that allow precisely timed covalent crosslinking of ligands and targets. Using a unique technique we have synthesized azidoblebbistatin, which is a derivative of blebbistatin, the most widely used myosin inhibitor. Without UV irradiation azidoblebbistatin exhibits identical inhibitory properties to those of blebbistatin. Using UV irradiation, azidoblebbistatin can be covalently crosslinked to myosin, which greatly enhances its in vitro and in vivo effectiveness. Photo-crosslinking also eliminates limitations associated with the relatively low myosin affinity and water solubility of blebbistatin. The wavelength used for photo-crosslinking is not toxic for cells and tissues, which confers a great advantage in in vivo tests. Because the crosslink results in an irreversible association of the inhibitor to myosin and the irradiation eliminates the residual activity of unbound inhibitor molecules, azidoblebbistatin has a great potential to become a highly effective tool in both structural studies of actomyosin contractility and the investigation of cellular and physiological functions of myosin II. We used azidoblebbistatin to identify previously unknown low-affinity targets of the inhibitor (EC 50 ≥ 50 μM) in Dictyostelium discoideum, while the strongest interactant was found to be myosin II (EC 50 = 5 μM). Our results demonstrate that azidoblebbistatin, and potentially other azidated drugs, can become highly useful tools for the identification of strong-and weak-binding cellular targets and the determination of the apparent binding affinities in in vivo conditions. interactom profile | azidation | photoactivation V arious biological processes, including muscle contraction, cell migration, differentiation, and cytokinesis require the activity of myosin II, a class of actin-based ATP-driven motor proteins. Cell-permeable small molecules that can perturb myosin functions have greatly aided the dissection and understanding of molecular processes underlying the above phenomena. Myosin II inhibitors described to date include 2,3-butanedione monoxime (BDM) (1, 2), N-benzyl-p-toluenesulphonamide (BTS) (3), and blebbistatin (4-6). As BDM has turned out to have a broad effect on many other proteins (7) and the inhibitory effect of BTS is limited to fast skeletal muscle myosin, until now blebbistatin has been the only potent tool for specific blocking of myosin II-dependent processes in various species and cell types. Recent data have shown that halogenated pseudilins also have nonspecific inhibitory effects on myosin II isoforms (8-10).In vitro, blebbistatin inhibits vertebrate striated muscle and nonmuscle myosin II isoforms as well as Dictyostelium discoideum (Dd) myosin II by about 95%, with an IC 50 of 0.5-5 μM (11). Vertebrate smooth muscle and Acanthamoeba myosin II are incompletely inhibited even at high blebbistatin concentrations. In vivo experiments performed with Dd showed that the effective inhibition of myosin II-dependent processes, including growth in...

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“…The functionalizations including arylation, alkoxylation, acylation, olefination, amidation, nitration and halogenation have been achieved [15] . So far, the halogenation of aromatics catalyzed by Pd [15][16][17][18][19][20][21] , Rh [22,23] , Au [7] and Cu [24][25][26][27][28][29][30][31][32] has been developed. In the past decade, C-H activation/C-X(X=halogen) coupling catalyzed by precious metal has made great progress.…”

mentioning

confidence: 99%

Cu-catalyzed aryl C-H halogenation using N-halosuccinimides via assistance of benzoic acid

Gao

Lin

2015

Chem. Res. Chin. Univ.

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Aryl halides are a kind of extremely valuable compounds used in transition-metal-catalyzed coupling reactions, as well as important structure motifs in many natural products and manufactured drugs [1,2] . The classical approach for preparation of haloarenes is electrophilic aromatic substitution(EAS) using various halogenating reagents or oxidative halogenations with halogenating reagent generated in situ from halides and oxidants, such as peroxide, oxygen and meta-cholorperoxybenzoic acid(mCPBA) [3,4] . However, harsh reaction conditions are required for halogenation of less active aromatics. orthoMetalation followed by halogen quenching is another approach for halogenation of aromatics [5] . However, there are obvious drawbacks for these methods，such as low regioselectivity, harsh conditions and even dangerous procedures. Therefore, the development of an alternative and practical way remains challenge in organic synthesis.As a complementary method for halogenation of deactivated aromatics, in 2004, a means to halogenate aromatics, including deactivated ones was developed by Olah and co-workers [6] , with N-halosuccinimides(NXS)/BF 3 -H 2 O system. And in 2010, Wang and co-workers [7] achieved an efficient Au-catalyzed halogenation of aromatics with electron-donating group(EDG) or electron-withdrawing group(EWG) using NXS. In addition, transtion-metal-catalyzed C-H bond functionalization of aromatic compounds has attracted considerable attention and has gradually become a benign and environmentally friendly tool in organic synthesis [8][9][10][11][12][13][14] . The functionalizations including arylation, alkoxylation, acylation, olefination, amidation, nitration and halogenation have been achieved [15] . So far, the halogenation of aromatics catalyzed by Pd [15][16][17][18][19][20][21] , Rh [22,23] , Au [7] and Cu [24][25][26][27][28][29][30][31][32] has been developed. In the past decade, C-H activation/C-X(X=halogen) coupling catalyzed by precious metal has made great progress. In particular, there have been many reports about Pd-catalyzed halogenation. However, residue of poisonous and harmful heavy metal and high cost have restricted its practical application. C-H functionalization catalyzed by ordinary transition metal is the direction of future development, and has profound significance on the development of organic chemistry theory and application in the chemical industry. Halogenation reactions with inexpensive Cu as metal catalyst have been developed recently. We have previously exploited a highly efficient and practical protocol for the selective preparation of mono-and di-halogenated 2-arylpyridine via conjunctive use of carboxylic acids and solvents [32] . Using stoichiometric amount of CuX(X=Br or Cl) is a disadvantage for the method. In our ongoing investigation of the reaction, we have drawn our attention to counter ions of Cu-catalysts owing to the halide effects of transition metal catalysis. Halide ions of transition-metal complex are not only counter ions, but also ligands with important prope...

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Gold‐Catalyzed Halogenation of Aromatics by N‐Halosuccinimides

Cited by 236 publications

References 62 publications

Silver Catalyzed Bromination of Aromatics with N-bromosuccinimide

Silver Catalyzed Bromination of Aromatics with N-bromosuccinimide

Azidoblebbistatin, a photoreactive myosin inhibitor

Cu-catalyzed aryl C-H halogenation using N-halosuccinimides via assistance of benzoic acid

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