- Dehydrogenation of Primary Alkyl Azides to Nitriles Catalyzed by Pincer Iridium/Ruthenium Complexes
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Pincer metal complexes exhibit superior catalytic activity in the dehydrogenation of plain alkanes, but find limited application in the dehydrogenation of functionalized organic molecules. Starting from easily accessible primary alkyl azides, here we report an efficient dehydrogenation of azides to nitriles using pincer iridium or ruthenium complexes as the catalysts. This method offers a route to cyanide-free preparation of nitriles without carbon chain elongation and without the use of strong oxidants. Both benzyl and linear aliphatic azides can be dehydrogenated with tert-butylethylene as the hydrogen acceptor to afford nitriles in moderate to high yields. Various functional groups can be tolerated, and the H?C?C?H bond dehydrogenation does not occur for linear alkyl azide substrates. Furthermore, the pincer Ir catalytic system was found to catalyze the direct azide dehydrogenation without the use of a sacrificial hydrogen acceptor.
- Gan, Lan,Jia, Xiangqing,Fang, Huaquan,Liu, Guixia,Huang, Zheng
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p. 3661 - 3665
(2020/06/02)
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- A Transition-Metal-Free One-Pot Cascade Process for Transformation of Primary Alcohols (RCH2OH) to Nitriles (RCN) Mediated by SO2F2
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A new transition-metal-free one-pot cascade process for the direct conversion of alcohols to nitriles was developed without introducing an “additional carbon atom”. This protocol allows transformations of readily available, inexpensive, and abundant alcohols to highly valuable nitriles.
- Jiang, Ying,Sun, Bing,Fang, Wan-Yin,Qin, Hua-Li
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p. 3190 - 3194
(2019/05/21)
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- Pd(II)-immobilized on a nanoporous triazine-based covalent imine framework for facile cyanation of haloarenes with K4Fe(CN)6
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A porous covalent organic framework incorporated with both imine and triazine functionalities (TPA-TCIF) was synthesized by Schiff-base condensation of 2,4,6-tris(4-aminophenyl)triazine and tris(4-formylphenyl)amine under the solvothermal condition of a 1-butanol:1,2-dichlorobenzene mixture. The resulting TPA-TCIF was a highly ordered crystalline network with surface area of 2938 m2 g?1, which was among the highest reported imine-based porous covalent organic frameworks. TPA-TCIF was also stable in water and other organic solvents. Pd(II) was immobilized into TPA-TCIF network and the resultant Pd/TPA-TCIF was tested as a catalyst for the additive-free cyanation of haloarenes with non-toxic K4[Fe(CN)6]. The catalyst showed excellent catalytic activity, and both electron-donating / -withdrawing groups attached to the para- and meta-positions of bromoarenes produced the respective nitriles with good to excellent yields. The catalyst could be reused up to five times without noticeable loss of activity or catalyst poisoning by cyanide ions during the reaction.
- Puthiaraj, Pillaiyar,Yu, Kwangsun,Shim, Sang Eun,Ahn, Wha-Seung
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- Dual Ligand-Enabled Nondirected C-H Cyanation of Arenes
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Aromatic nitriles are key structural units in organic chemistry and, therefore, highly attractive targets for C-H activation. Herein, the development of an arene-limited, nondirected C-H cyanation based on the use of two cooperatively acting commercially available ligands is reported. The reaction enables the cyanation of arenes by C-H activation in the absence of directing groups and is therefore complementary to established approaches.
- Chen, Hao,Mondal, Arup,Wedi, Philipp,Van Gemmeren, Manuel
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p. 1979 - 1984
(2019/02/19)
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- Nickel-catalyzed cyanation of aryl halides and triflates using acetonitrile: Via C-CN bond cleavage assisted by 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine
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We developed a non-toxic cyanation reaction of various aryl halides and triflates in acetonitrile using a catalyst system of [Ni(MeCN)6](BF4)2, 1,10-phenanthroline, and 1,4-bis(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (Si-Me4-DHP). Si-Me4-DHP was found to function as a reductant for generating nickel(0) species and a silylation reagent to achieve the catalytic cyanation via C-CN bond cleavage.
- Ueda, Yohei,Tsujimoto, Nagataka,Yurino, Taiga,Tsurugi, Hayato,Mashima, Kazushi
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p. 994 - 999
(2019/02/03)
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- Ligand-Promoted Non-Directed C?H Cyanation of Arenes
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This article reports the first example of a 2-pyridone accelerated non-directed C?H cyanation with an arene as the limiting reagent. This protocol is compatible with a broad scope of arenes, including advanced intermediates, drug molecules, and natural products. A kinetic isotope experiment (kH/kD=4.40) indicates that the C?H bond cleavage is the rate-limiting step. Also, the reaction is readily scalable, further showcasing the synthetic utility of this method.
- Liu, Luo-Yan,Yeung, Kap-Sun,Yu, Jin-Quan
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supporting information
p. 2199 - 2202
(2019/01/24)
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- Electrochemical C-H cyanation of electron-rich (Hetero)arenes
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A straightforward method for the electrochemical C-H cyanation of arenes and heteroarenes that proceeds at room temperature in MeOH, with NaCN as the reagent in a simple, open, undivided electrochemical cell is reported. The platinum electrodes are passivated by ad-sorbed cyanide, which allows conversion of an exceptionally broad range of electron-rich substrates all the way down to dialkyl arenes. The cyanide electrolyte can be replenished with HCN, opening opportunities for salt-free industrial C-H cyanation.
- Hayrapetyan, Davit,Rit, Raja K.,Kratz, Markus,Tschulik, Kristina,Goo?en, Lukas J.
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supporting information
p. 11288 - 11291
(2018/10/20)
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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.
- -
-
Paragraph 0134-0136
(2018/05/30)
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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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- 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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- A room temperature cyanation of (hetero)aromatic chlorides by an air stable nickel(II) XantPhos precatalyst and Zn(CN)2
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A methodology for the synthesis of (hetero)aromatic nitriles from aryl chlorides at room temperature has been developed. This methodology uses an air and moisture stable nickel(ii) XantPhos precatalyst and Zn(CN)2 as the cyanide (CN-) source.
- Beattie, D. Dawson,Schareina, Thomas,Beller, Matthias
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supporting information
p. 4291 - 4294
(2017/07/10)
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- Acetonitrile as a cyanating reagent: Cu-catalyzed cyanation of arenes
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A novel approach to the Cu-catalyzed cyanation of simple arenes using acetonitrile as an attractive cyano source has been documented. The C-H functionalization of arenes without directing groups involves a sequential iodination/cyanation to give the desired aromatic nitriles in good yields. A highly efficient Cu/TEMPO system for acetonitrile C-CN bond cleavage has been discovered. TEMPO is used as a cheap oxidant and enables the reaction to be catalytic in copper. Moreover, TEMPOCH2CN 6 has been identified as the active cyanating agent and shows high reactivity for forming the -CN moiety.
- Zhu, Yamin,Zhao, Mengdi,Lu, Wenkui,Li, Linyi,Shen, Zengming
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supporting information
p. 2602 - 2605
(2015/06/16)
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- Facile one-pot transformation of arenes into aromatic nitriles under metal-cyanide-free conditions
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Electron-rich arenes bearing methyl or methoxy groups on the aromatic ring were treated with dichloromethyl methyl ether and ZnBr2, and then with molecular iodine and aq. ammonia to give the corresponding aromatic nitriles in good yields. Using this method, febuxostat was efficiently prepared from 4-bromophenol in four steps. The method can be used for the preparation of aromatic nitriles from arenes in one pot under metal-cyanide-free conditions. Various electron-rich arenes could be effectively converted into the corresponding aromatic nitriles in good yields, by treatment with ZnBr2 and dichloromethyl methyl ether, followed by reaction with molecular iodine and aq. ammonia.
- Tamura, Toshiyuki,Moriyama, Katsuhiko,Togo, Hideo
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p. 2023 - 2029
(2015/03/18)
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- Iron(II)-catalyzed direct cyanation of arenes with aryl(cyano)iodonium triflates
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A direct oxidative cyanation of arenes under FeII catalysis with 3,5-di(trifluoromethyl)phenyl(cyano)iodonium triflate (DFCT) as the cyanating agent has been developed. The reaction is applicable to wide range of aromatic substrates, including polycyclic structures and heteroaromatic compounds. Copyright
- Shu, Zhibin,Ji, Wenzhi,Wang, Xi,Zhou, Yujing,Zhang, Yan,Wang, Jianbo
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supporting information
p. 2186 - 2189
(2014/03/21)
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- Practical one-pot conversion of aryl bromides and β-bromostyrenes into aromatic nitriles and cinnamonitriles
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Various aryl bromides were efficiently converted into the corresponding aromatic nitriles in good yields by the treatment with Mg turnings and subsequently DMF, followed by treatment with molecular iodine and aq NH 3. The same treatment of aryl bromides, which are weakly reactive to Mg turnings, with iPrMgCl·LiCl and subsequently DMF, followed by the treatment with molecular iodine and aq NH3 also afforded the corresponding aromatic nitriles in good yields. On the other hand, when N-formylpiperidine was used instead of DMF, p-substituted β-bromostyrenes were converted into the corresponding p-substituted cinnamonitriles, i.e., α,β-unsaturated nitriles, in good to moderate yields by the same procedure. The reactions were carried out by means of a simple experimental procedure and did not require any toxic metal cyanides or expensive rare metals. Therefore, the present reactions are practical and environmentally benign one-pot methods for the preparation of aromatic nitriles, cinnamonitriles, and aliphatic nitriles from aryl bromides, β-bromostyrenes, and alkyl bromides, respectively, through the formation of Grignard reagents and their DMF or N-formylpiperidine adducts.
- Ishii, Genki,Harigae, Ryo,Moriyama, Katsuhiko,Togo, Hideo
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p. 1462 - 1469
(2013/02/25)
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- Transformation of aromatic bromides into aromatic nitriles via formations of grignard reagents and their DMF adducts
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Various aromatic bromides were efficiently transformed into the corresponding aromatic nitriles in good yields via the formations of Grignard reagents and subsequently N,N-dimethyl formamide (DMF) adducts, followed by treatment with molecular iodine (I2) in aq NH3 at room temperature. The present reaction is an easy and practical method for the preparation of aromatic nitriles from aromatic bromides with less toxic reagents, such as Mg, DMF, I2, and aq NH3.
- Ishii, Genki,Moriyama, Katsuhiko,Togo, Hideo
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experimental part
p. 2404 - 2406
(2011/05/16)
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- One-pot conversion of aromatic bromides and aromatics into aromatic nitriles via aryllithiums and their DMF adduct
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Various aromatic bromides and iodides were smoothly converted into the corresponding aromatic nitriles in good to moderate yields by the treatment with n-butyllithium and subsequently DMF, followed by treatment with molecular iodine in aq NH3. The same treatment of typical aromatics and heteroaromatics with n-butyllithium and subsequently DMF, followed by treatment with molecular iodine in aq NH3 also provided the corresponding aromatic nitriles in good yields. Moreover, the same treatment of aromatic bromides and aromatics with half amount of DIH (1,3-diiodo-5,5- dimethylhydantoin) instead of molecular iodine worked effectively to give the corresponding aromatic nitriles, respectively, in good yields. These reactions are novel and environmentally benign one-pot methods for the preparation of aromatic nitriles from aromatic bromides and aromatics, respectively, through the formation of aryllithiums and their DMF adducts.
- Ushijima, Sousuke,Moriyama, Katsuhiko,Togo, Hideo
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experimental part
p. 958 - 964
(2011/03/19)
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- A mild and efficient palladium-catalyzed cyanation of aryl mesylates in water or tBuOH/water
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Cool and compatible: Aryl mesylates and tosylates underwent palladium-catalyzed cyanation under mild, aqueous conditions at 65-80°C (see scheme). In many cases, water could be used as the reaction medium without a cosolvent, and a variety of substituents R, such as keto, aldehyde, ester, free amine, and nitrile groups, remained intact during the transformation. Cy=cyclohexyl, Ms=methanesulfonyl, Ts=p-toluenesulfonyl.
- Yeung, Pui Yee,So, Chau Ming,Lau, Chak Po,Kwong, Fuk Yee
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supporting information; experimental part
p. 8918 - 8922
(2011/02/24)
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- One-pot conversion of aromatic bromides and aromatics into aromatic nitriles
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Various aromatic bromides and iodides were smoothly converted into the corresponding aromatic nitriles in good to moderate yields by the treatment with butyllithium and subsequently DMF, followed by treatment with molecular iodine in aqueous ammonia. The
- Ushijima, Sousuke,Togo, Hideo
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experimental part
p. 1562 - 1566
(2010/09/05)
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- Oxidation of Aromatic Compounds. V. Oxidation of Substituted Benzonitriles and 2,4,6-Triaryl-1,3,5-Triazines in System HSO3F-PbO2
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Low-temperature oxidation of substituted benzonitriles by the system HSO3F-PbO2 proceeds with intermediate formation of cation-radicals and leads to substitution of hydrogen atoms of the methyl group or benzene ring. This reaction provides a route for preparation of chloromethylsubstituted benzonitriles, diarylmethanes, diaryls, arylfluorosulfonates and substituted benzamides with cyano groups. In the case of methyl derivatives of 2,4,6-triphenyl-1,3,5-triazine substitution of the first and then the second hydrogen atom of the same methyl group transforms it into hydroxy or chloromethyl group, or into the aldehyde function.
- Rudenko,Salfetnikova,Vasil'ev
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p. 1447 - 1470
(2007/10/03)
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- Initial steps in the reductive condensation of trichloromethylarenes with hydroxylamine and hydrazines in pyridine
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Data concerning the initial steps in the reductive condensation of trichloromethylarenes with hydroxylamine or hydrazines in pyridine have been obtained.High yields of the products of the reductive condensation obtained even at equimolar ratios of trichloromethylarene with hydroxylamine or hydrazine as well as the formation of unusual products, i.e., 4-pyridylhydrazones of substituted benzaldehydes, have been interpreted as the results of the participation of pyridine in the reaction as a reductive agent. - Key words: trichloromethylarenes, reductive condensation with hydroxylamine or hydrazines, role of pyridine; 4-pyridylhydrazones of substituted benhaldehydes.
- Belen'kii, L. I.,Poddubnyi, I. S.,Krayushkin, M. M.
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p. 1844 - 1848
(2007/10/02)
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- Methyl Group Effect on the Proton Affinity of Methylated Acetophenones Studied by Two Mass Spectrometric Techniques
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The proton affinities (PA) of all isomeric dimethylacetophenones were determined using the "kinetic method" with a tandem mass spectrometer and by measurements of the proton transfer equilibrium in the gas phase by Fourier transform ion cyclotron resonance mass spectrometry.For both methods acetophenone and p-methylacetophenone, with well known PA values, were used as reference bases.Both methods yielded identical PA values for all dimethylacetophenones.The PA of the dimethylacetophenones were in a narrow range between 872 and 880 kJ mol-1 except for 2,6-dimethylacetophenone, for which a PA of 856 kJ mol-1 was found.The results are discussed in terms of possible mesomeric structures stabilizing the positive charge with regard to the substitution pattern in the phenyl ring.Obviously, the significant smaller PA of 2,6-dimethylacetophenone compared with the other isomers is due to the distortion of the conjugation of the C-O double bond with the aromatic ? system.
- Kukol, A.,Strehle, F.,Thielking, G.,Gruetzmacher, H.-Fr.
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p. 1107 - 1110
(2007/10/02)
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- Reductive condensation of trichloromethylarenes with hydroxylamine and hydrazines in pyridine
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The interaction of trichloromethylarenes with hydroxylamine in pyridine involves the reductive oximation of aryltrichloromethanes. Further transformations of the oximes in the reaction course can result in the formation of nitriles or 3,5-diaryl-1,2,4-oxadiazoles as final products. The conversion depth depends on reaction conditions and structures of trichloromethyl-arenes. When hydrazines used instead of hydroxylamine, respectivebenzaldehyde hydrazones or azines are obtained.
- Belen'kii,Brokhovetskii,Krayushkin
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p. 447 - 456
(2007/10/02)
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- Mechanism and models for homogeneous copper mediated ligand exchange reactions of the type: CuNu + ArX (*) ArNu + CuX
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The title reactions are an important class of copper mediated nucleophilic aromatic substitution processes, which constitute a useful tool in the molecular design and synthesis of small molecules.We report the results of extensive investigation of these processes, primarily focussing on cyanodeiodination (ArI + CuCN CuI + ArCN).Among the interesting features of these processes are: (a) an unusual rate equation involving autocatalysis by CuI product; (b) retardation by both excess nucleophile (as KCN) and excess leaving group (as KI), which complete with ArX to complex with CuNu; (c) only cuprous nucleophiles are active (ligand exchanged products from cupric salts arise from prior redox equilibria which form CuNu); (d) the halogen effect is large (kI ca 40 - 100 kBr ca 300 - 5000 kCl) but the Hammett q value is zero; (e) ortho-alkyl groups do not hinder the reaction ( and actually cause mild acceleration by relief of steric strain).Finally, the introduction of an ortho-COO- group accelerates the reaction by a factor of 104 - 105 , but the general features of the accelerated reactions are also the same, again indicating a common mechanism, with entropic acceleration by ortho-carboxylate.Both kinetic and thermodynamic factors were considered in detail, the latter apparently for the first time.Applications to practical syntheses are considered, and novel mechanistic models for these interesting processes are discussed.
- Couture, Christiane,Paine, Anthony James
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p. 111 - 120
(2007/10/02)
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- Synthesis, Thermal and Photochemical Reactions of New Mesoionic 1,3,2-Oxathiazolones
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The synthesis and spectroscopic data of the new mesoionic 1,3,2-oxathiazolones 3b, c, e are described.As cyclic thiocarbonyl imine, 3e reacts with dimethyl acetylenedicarboxylate at 80 deg C with evolution of carbon dioxide to produce the 5-arylisothiazole derivative 6e (80percent).On the other hand, the visible light-induced fragmentation of 3e leads to a nitrile sulfide intermediate of type 10 which suffers unimolecular decay with formation of sulfur and the arylnitrile 11e or which can be partially trapped with dimethyl acethylenedicarboxylate to form the iosmeric 3-arylisothiazole derivative 13e (29-21percent).The analogous photochemical decay of 3c in the presence of dimethyl acetylenedicarboxylate proceeds with formation of the isothiazole derivative 13c besides sulfur and the nitrile 11c, whereas the nitrile sulfide 10b - photochemically generated from 3b - does not more react with formation of an isothiazole derivative.
- Gotthardt, Hans,Reiter, Friedemann,Kromer, Claudia
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p. 1025 - 1034
(2007/10/02)
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