- C4-arylation and domino C4-arylation/3,2-carbonyl migration of indoles by tuning Pd catalytic modes: Pd(i)-Pd(ii) catalysisvs.Pd(ii) catalysis
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Efficient C4-arylation and domino C4-arylation/3,2-carbonyl migration of indoles have been developed. The former route enables C4-arylation in a highly efficient and mild manner and the latter route provides an alternative straightforward protocol for synthesis of C2/C4 disubstituted indoles. The mechanism studies imply that the different reaction pathways were tuned by the distinct acid additives, which led to either the Pd(i)-Pd(ii) pathway or Pd(ii) catalysis.
- Cheng, Yaohang,Yu, Shijie,He, Yuhang,An, Guanghui,Li, Guangming,Yang, Zhenyu
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Read Online
- Decarboxylation of indole-3-carboxylic acids under metal-free conditions
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Two reaction systems have been developed for the decarboxylation of indole-3-carboxylic acids. The decarboxylation can be achieved smoothly under K2CO3-catalyzed or acetonitrile-promoted basic conditions. It provided an efficient and simple method for the transformation of indole-3-carboxylic acids and the corresponding indoles were isolated with good to excellent yields. From the experimental facts, we put forward the possible reaction mechanism.
- Chen, Xia,Zhou, Xiao-Yu
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supporting information
p. 805 - 812
(2020/02/20)
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- Reductive cyanation of organic chlorides using CO2 and NH3 via Triphos–Ni(I) species
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Cyano-containing compounds constitute important pharmaceuticals, agrochemicals and organic materials. Traditional cyanation methods often rely on the use of toxic metal cyanides which have serious disposal, storage and transportation issues. Therefore, there is an increasing need to develop general and efficient catalytic methods for cyanide-free production of nitriles. Here we report the reductive cyanation of organic chlorides using CO2/NH3 as the electrophilic CN source. The use of tridentate phosphine ligand Triphos allows for the nickel-catalyzed cyanation of a broad array of aryl and aliphatic chlorides to produce the desired nitrile products in good yields, and with excellent functional group tolerance. Cheap and bench-stable urea was also shown as suitable CN source, suggesting promising application potential. Mechanistic studies imply that Triphos-Ni(I) species are responsible for the reductive C-C coupling approach involving isocyanate intermediates. This method expands the application potential of reductive cyanation in the synthesis of functionalized nitrile compounds under cyanide-free conditions, which is valuable for safe synthesis of (isotope-labeled) drugs.
- Dong, Yanan,Li, Yuehui,Yang, Peiju,Zhao, Shizhen
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- A carboxamide is the cyanogen source of aromatic nitrile to the preparation method of the (by machine translation)
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The invention discloses a method for preparing aromatic nitrile, is under the action of the nickel catalyst, in order to carboxamide is the cyanogen source, and with various substituents haloarene coupled reactions, preparing aromatic nitrile. The reaction temperature is 100 - 160 °C, the reaction time is 6 - 24 hours. It overcomes the traditional aromatic nitrile of the synthesis method operation of complex steps, requires the use of a toxic, more expensive, functionalization of the cyanogen source as the reaction raw material and the like. Compared with the traditional method, this method is simple to use cheap, green non-toxic of the formamide is cyano sources; without the need of external dehydrating agent, formamide in the nickel catalyst of the catalytic dehydration at the same time, with a nickel catalyst in coordination with the halogenated aromatic hydrocyanation, more economic, high-efficiency, environmental protection; at the same time the method exhibits good substrate universality, to air, moisture, light are not sensitive, high yield, product separation and purification is simple, with wide application. (by machine translation)
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Paragraph 0015; 0016; 0017; 0018-0024; 0116; 0117-0121
(2019/05/08)
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- Ni-Mediated Generation of "cN" Unit from Formamide and Its Catalysis in the Cyanation Reactions
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The in situ generation of a "cyano" unit from readily available organic precursors is of high interest in synthetic chemistry. Herein, we report the first example of Ni-mediated dehydration of formamide to form "CN" and its subsequent catalytic applications in the hydrocyanation of alkynes and cyanation of aryl halides. Formamide can serve as a convenient source for the nitrile unit, in that it releases water as the only byproduct.
- Yang, Luo,Liu, Yu-Ting,Park, Yoonsu,Park, Sung-Woo,Chang, Sukbok
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p. 3360 - 3365
(2019/03/26)
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- A indole compound and its preparation method and application (by machine translation)
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The invention discloses a indole compound and its preparation method and application. The indole compounds of the structural formula such as formula (I) is shown. The indoles, rice galenical demonstrate the excellent inhibitory activity, the effect of most of the compound is obviously better than the positive control drug validamycin; especially compound I - 43, I - 44, I - 54, I - 73, II - 7 and II - 17, its galenical very good living body protection and treating effect, effect is better than the positive control; more specifically, compound I - 43 of the rice sheath blight bacteriostatic activity than validamycin activity is improved by nearly 300 times. The indole compounds in the prevention and/or treatment of rice sheath blight has great application prospects. In addition the compound of the invention is simple in construction, the preparation method is simple, and is suitable for large-scale industrial production. (I). (by machine translation)
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Paragraph 0131; 0142; 0143
(2018/10/02)
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- Catalytic Cyanation Using CO2 and NH3
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Li and co-workers describe the catalytic cyanation of organic halides with CO2 and NH3. In the presence of Cu2O/DABCO as the catalyst, a variety of aromatic bromides and iodides were transformed to the desired nitrile products with broad functional-group tolerance. Both 13C- and/or 15N-labeled nitriles were obtained conveniently with appropriately isotope-labeled CO2 and NH3. Construction of functionalized chemical compounds from small molecules in a highly selective and efficient manner is crucial for sustainable development. The chemical-based manufacturing sector of the future should aim to produce chemicals from very simple and abundant resources, just as nature uses CO2 and N2 to generate sugars, amino acids, and so forth. In practice, however, the utilization of CO2 for the generation of industrial products, such as drugs and related intermediates, still remains a major challenge. Here, we describe the facile cyanide-free production of high-value nitriles with CO2 and NH3 as the sole sources of carbon and nitrogen, respectively. This practical and catalytic methodology provides a unique strategy for the utilization of small molecules for sustainable and cost-effective applications. Selective cyanation of aryl halides was achieved with CO2 and NH3 as the only sources of carbon and nitrogen, respectively. In the presence of Cu catalysts under low pressure (3 atm), a variety of aromatic iodides and bromides were transformed to the desired nitrile products without the use of toxic metal cyanides. Notably, olefins, esters, amides, alcohols, and amino groups were tolerated. Mechanistic studies suggest that Cu(III)-aryl insertion by isocyanate intermediates is involved. [13C,15N]-labeled nitriles were conveniently accessible from the respective isotope-labeled CO2 and NH3 via this methodology.
- Wang, Hua,Dong, Yanan,Zheng, Chaonan,Sandoval, Christian A.,Wang, Xue,Makha, Mohamed,Li, Yuehui
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supporting information
p. 2883 - 2893
(2019/01/05)
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- Cyaniding method for preparing nitrile compound
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The invention provides a cyaniding method for preparing a nitrile compound. Organic halide or pseudohalide, CO2 and NH3 which are low in price and are easily obtained and a reducing agent react, a selective cyaniding reaction is conducted in the presence of a transition metal catalyst, and the target product namely organic the nitrile compound is obtained. According to the cyaniding method for preparing the nitrile compound, a new reaction route is used, through a CO2 and NH3 reaction of metal catalysis, dehalogenation cyaniding or quasi halide cyaniding of halide or pseudohalide is directly achieved through a one-pot method, the problem is solved that a traditional cyanation reaction needs equivalent toxic cyanide, a new direct and convenient method for preparing isotope-labeled nitrile compounds is provided at the same time, and the method can be applied to medicine, tracing, biology and medicine research and development.
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Paragraph 0152-0154
(2018/05/30)
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- Nickel-Catalyzed Cyanation of Aryl Chlorides and Triflates Using Butyronitrile: Merging Retro-hydrocyanation with Cross-Coupling
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We describe a nickel-catalyzed cyanation reaction of aryl (pseudo)halides that employs butyronitrile as a cyanating reagent instead of highly toxic cyanide salts. A dual catalytic cycle merging retro-hydrocyanation and cross-coupling enables the conversion of a broad array of aryl chlorides and aryl/vinyl triflates into their corresponding nitriles. This new reaction provides a strategically distinct approach to the safe preparation of aryl cyanides, which are essential compounds in agrochemistry and medicinal chemistry.
- Yu, Peng,Morandi, Bill
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supporting information
p. 15693 - 15697
(2017/12/02)
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- Indolyne experimental and computational studies: Synthetic applications and origins of selectivities of nucleophilic additions
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Efficient syntheses of 4,5-, 5,6-, and 6,7-indolyne precursors beginning from commercially available hydroxyindole derivatives are reported. The synthetic routes are versatile and allow access to indolyne precursors that remain unsubstituted on the pyrrole ring. Indolynes can be generated under mild fluoride-mediated conditions, trapped by a variety of nucleophilic reagents, and used to access a number of novel substituted indoles. Nucleophilic addition reactions to indolynes proceed with varying degrees of regioselectivity; distortion energies control regioselectivity and provide a simple model to predict the regioselectivity in the nucleophilic additions to indolynes and other unsymmetrical arynes. This model has led to the design of a substituted 4,5-indolyne that exhibits enhanced nucleophilic regioselectivity.
- Im, G-Yoon J.,Bronner, Sarah M.,Goetz, Adam E.,Paton, Robert S.,Cheong, Paul H.-Y.,Houk,Garg, Neil K.
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supporting information; experimental part
p. 17933 - 17944
(2011/02/26)
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- Process for catalytically preparing aromatic or heteroaromatic nitriles
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The present invention relates to a process for preparing optionally substituted aromatic or heteroaromatic nitriles starting from haloaromatics. These are reacted in a copper-catalysed reaction with potassium hexacyanoferrate(II) or potassium hexacyanoferrate(III) in the presence of heteroaromatic amines.
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Page/Page column 3
(2009/04/24)
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- A bio-inspired copper catalyst system for practical catalytic cyanation of aryl bromides
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A general and environmentally improved protocol for the cyanation of aryl halides with the nontoxic cyanide source potassium hexacyanoferrate(II) {K 4[Fe(CN)6]} using copper catalysis and a ligand system based on 1-alkyl-1H-imidazoles is presented. The advantages of this system are a wide substrate range, high selectivity, easy handling, and inexpensive reagents.
- Schareina, Thomas,Zapf, Alexander,Cotte, Alain,Mueller, Nikolaus,Beller, Matthias
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experimental part
p. 3351 - 3355
(2009/06/06)
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- A state-of-the-art cyanation of aryl bromides: A novel and versatile copper catalyst system inspired by nature
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A general protocol for the cyanation of aryl halides with the nontoxic cyanide source K4[Fe(CN)6] using copper catalysis and a ligand system based on 1-alkylimidazoles is presented. The advantages of this system are the high selectivity, a unique substrate range, easy handling, and inexpensive reagents.
- Schareina, Thomas,Zapf, Alexander,Maegerlein, Wolfgang,Mueller, Nikolaus,Beller, Matthias
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p. 6249 - 6254
(2008/02/13)
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- Mild and general methods for the palladium-catalyzed cyanation of aryl and heteroaryl chlorides
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New methods for the palladium-catalyzed cyanation of aryl and heteroaryl chlorides have been developed, featuring sterically demanding, electron-rich phosphines. Highly challenging electron-rich aryl chlorides, in addition to electron-neutral and electron-deficient substrates, as well as nitrogen- and sulfur-containing heteroaryl chlorides can all undergo efficient cyanation under relatively mild conditions using readily available materials. In terms of substrate scope and temperature, these methods compare very favorably with the state-of-the-art cyanations of aryl chlorides.
- Littke, Adam,Soumeillant, Maxime,Kaltenbach III, Robert F.,Cherney, Robert J.,Tarby, Christine M.,Kiau, Susanne
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p. 1711 - 1714
(2008/02/02)
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- Copper-catalyzed cyanation of heteroaryl bromides: A novel and versatile catalyst system inspired by nature
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An improved copper catalyst system for the cyanation of heteroaryl halides leading to substituted heteroaryl nitriles is described. The catalyst system consists of simple CuI and N-alkylimidazoles, and mimics known Cu-containing metalloproteins. It is stable, commercially available, cheap and easily tunable. By using inexpensive and non-toxic K4[Fe(CN)6] and the novel Cu catalysts we were able to cyanate both activated and non-activated heteroarenes with high yield and selectivity. The generality of the procedure is demonstrated by a variety of different examples, some of which did not react under other known methods. Georg Thieme Verlag Stuttgart.
- Schareina, Thomas,Zapf, Alexander,M?gerlein, Wolfgang,Müller, Nikolaus,Beller, Matthias
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p. 555 - 558
(2007/10/03)
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- N-arylindoles and their use as herbicides
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Substituted N-arylindoles, a process for producing them and their use as herbicides. In particular, substituted N-arylindoles of the formula STR1 are disclosed in which: R is hydrogen; halogen; nitro; cyano; alkyl; alkoxy; alkenyloxy; alkynyloxy; alkoxyal
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- N-arylindoles and their use as herbicides
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Substituted N-arylindoles, a process for producing them and their use as herbicides. In particular, substituted N-arylindoles of the formula STR1 are disclosed in which: R is hydrogen; halogen; nitro; cyano; alkyl; alkoxy; alkenyloxy; alkynyloxy; alkoxyal
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- A CONVENIENT SYNTHETIC APPROACH TO 4-SUBSTITUTED INDOLES
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A simple and practical synthetic method for 4-halogenoindoles, 4-indolecarbaldehyde, 4-cyanoindole, and 4-methoxycarbonylindole is elaborated.
- Yamada, Fumio,Somei, Masanori
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p. 1173 - 1176
(2007/10/02)
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- Some Observations on the Formation of 1-Hydroxyindoles in the Leimgruber-Batcho Indole Synthesis
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The factors influencing the formation of 1-hydroxyindoles in the catalytic hydrogenation of β-dimethylamino-2-nitrostyrenes (Leimgruber-Batcho indole synthesis) have been investigated.Significant amounts of 1-hydroxyindoles were obtained only when the β-dimethylamino-2-nitrostyrene was substituted with an electron-withdrawing group at the 5 or 6 position.The proportion of 1-hydroxyindole formed relative to the normal indole product was found to increase as both the amount of catalyst and hydrogen pressure were decreased.
- Clark, Robin D.,Repke, David B.
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p. 121 - 125
(2007/10/02)
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- A SIMPLE PROCEDURE FOR THE PREPARATION OF INDOLES
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Indoles are easily prepared in 60-70percent yield from the corresponding o-nitrotoluenes by condensation with tripiperidinomethane, followed by reductive cyclization with aqueous titanous chloride.
- Lloyd, David H.,Nichols, David E.
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p. 4561 - 4562
(2007/10/02)
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- Synthesis of 4-(4-Alkyl-2-morpholinyl)indoles
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N-Substituted 4-(2-morpholinyl)indoles were prepared from 1-(t-butoxycarbonyl)-4-acetylindole (7) which was itself prepared from 4-cyanoindole.Bromination of ketone 7, followed by reaction with amines and subsequent sodium borohydride reduction, gave amin
- Clark, Robin D.
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p. 1393 - 1395
(2007/10/02)
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