- Design and synthesis of a magnetic hierarchical porous organic polymer: A new platform in heterogeneous phase-transfer catalysis
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Recyclable phase transfer catalysts containing magnetic nanoparticles (MNPs) have been known as a major trend towards sustainable catalysts. In this study, a novel class of magnetic porous polymer on the basis of calix[4]resorcinarene was synthesized starting from silica-coated Fe3O4 core-shell nanoparticles. This compound was found as an efficient phase transfer catalyst to the conversion of benzyl halides into benzyl azides and cyanides in good yields. The catalyst could be used at least for five consecutive cycles without appreciable loss in the catalytic activity.
- Mouradzadegun, Arash,Ganjali, Mohammad Reza,Mostafavi, Mahsa Alsadat
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- Crown ether functionalized magnetic hydroxyapatite as eco-friendly microvessel inorganic-organic hybrid nanocatalyst in nucleophilic substitution reactions: an approach to benzyl thiocyanate, cyanide, azide and acetate derivatives
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In this paper, high catalytic activity of 4′,4″-diformyl dibenzo-18-crown-6 anchored onto the functionalized magnetite hydroxyapatite (γ-Fe2O3@HAp–Crown) as a new, versatile and magnetically recoverable catalyst, was prepared. It evaluated as phase-transfer catalyst and molecular host system for nucleophilic substitution reactions of benzyl halides with thiocyanate, cyanide, azide and acetate anions in water. No evidence for the formation of by-products was observed and the products obtained in pure form without further purification. The nanocomposite was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. The synthesized nanocomposite was characterized by several techniques such as FT-IR, TGA-DTG, EDX, XRD, BET, FE-SEM, TEM and VSM.
- Azaroon, Maedeh,Kiasat, Ali Reza
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- Copper-Catalyzed Cyanation of N-Tosylhydrazones with Thiocyanate Salt as the "cN" Source
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A novel protocol for the synthesis of α-aryl nitriles has been successfully achieved via a copper-catalyzed cyanation of N-tosylhydrazones employing thiocyanate as the source of cyanide. The features of this method include a convenient operation, readily available substrates, low-toxicity thiocyanate salts, and a broad substrate scope.
- Huang, Yubing,Yu, Yue,Zhu, Zhongzhi,Zhu, Chuanle,Cen, Jinghe,Li, Xianwei,Wu, Wanqing,Jiang, Huanfeng
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p. 7621 - 7627
(2017/07/26)
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- One-Pot Preparation of C1-Homologated Aliphatic Nitriles from Aldehydes through a Wittig Reaction under Metal-Cyanide-Free Conditions
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A one-pot protocol to obtain C1-homologated aliphatic nitriles was achieved by treating aromatic and aliphatic aldehydes with the (methoxymethyl)triphenylphosphonium ylide followed by hydrolysis of the resulting methyl vinyl ethers with pTsOH (Ts = para-toluenesulfonyl) and treatment with molecular iodine and aqueous ammonia under metal cyanide free conditions. Neopentyl-type nitriles, which could not be obtained by conventional methods that involved conversion of the neopentyl alcohol into a tosylate and treatment with metal cyanide, were successfully obtained by using the present method.
- Ezawa, Masatoshi,Togo, Hideo
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p. 2379 - 2384
(2017/05/01)
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- A heterogeneous palladium catalyst hybridised with a titanium dioxide photocatalyst for direct C-C bond formation between an aromatic ring and acetonitrile
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A palladium catalyst hybridised with a titanium dioxide photocatalyst can promote cyanomethylation of an aromatic ring by using acetonitrile, where the photocatalyst activates acetonitrile to form a cyanomethyl radical before the C-C bond formation using the palladium catalyst.
- Yoshida, Hisao,Fujimura, Yuki,Yuzawa, Hayato,Kumagai, Jun,Yoshida, Tomoko
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supporting information
p. 3793 - 3795
(2013/05/22)
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- Magnetic nanoparticles grafted with β-cyclodextrin-polyurethane polymer as a novel nanomagnetic polymer brush catalyst for nucleophilic substitution reactions of benzyl halides in water
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The polymer coated magnetic nanoparticles has gained significant attention for potential applications in biomedicine, separations, and magnetic storage. In this study, β-cyclodextrin-polyurethane polymer coated Fe 3O4 magnetic nanoparticle as a novel class of hybrid organic/inorganic molecular catalyst was successfully prepared and evaluated as solid-liquid phase-transfer catalyst and molecular host system for nucleophilic substitution reactions. The nanocomposite has demonstrated the ability to catalytic the nucleophilic substitution reaction of benzyl halides with thiocyanate, azide, cyanide and acetate anions in water. No evidence for the formation of by-products for example isothiocyanate or alcohol was observed and the products obtained in pure form without further purification. The nanomagnetic polymer brush catalyst was easily removed from solution via application of a magnetic field, allowing straightforward recovery and reuse. Results obtained from scanning electron microscopy (SEM) and vibrating sample magnetometery (VSM) show that the synthesized magnetic nanocomposite are superparamagnetic with a mean diameter of 59 nm. The grafting of β-cyclodextrin-polyurethane polymer to Fe3O4 magnetic nanoparticle is confirmed by Fourier transform infrared spectroscopy (FT-IR).
- Kiasat, Ali Reza,Nazari, Simin
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- Application of β-cyclodextrin-polyurethane as a stationary microvessel and solid-liquid phase-transfer catalyst: Preparation of benzyl cyanides and azides in water
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Application of water tolerant heterogeneous catalyst, β-cyclodextrin- polyurethane (β-CDPU) polymer, as an efficient microvessel and polymeric host system for nucleophilic substitution reaction of benzyl halides with cyanide and azide anions in water has been described. The reactions gave only pure products, which did not require any further purification. The most important features of this method are high yields, clean reactions and that the catalyst can be recovered and recycled.
- Kiasat, Ali Reza,Nazari, Simin
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p. 102 - 105
(2013/01/15)
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- Copper-catalyzed cyanation of benzyl chlorides with non-toxic K 4[Fe(CN)6]
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Copper-based catalysts were firstly introduced into the cyanation of benzyl chlorides with non-toxic K4[Fe(CN)6]. The presented method avoids the use of extremely poisonous alkali cyanides and precious palladium catalysts. No other reagent apart from CuI, K4[Fe(CN) 6] and toluene was used in the cyanation, showing that the presented protocol is simple and practical. A series of benzyl chlorides were smoothly cyanated in up to 85% yield under the optimal conditions.
- Ren, Yunlai,Dong, Chuanhua,Zhao, Shuang,Sun, Yanpei,Wang, Jianji,Ma, Junying,Hou, Chaodong
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supporting information; experimental part
p. 2825 - 2827
(2012/07/17)
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- Pd-catalyzed cyanation of benzyl chlorides with nontoxic K 4[Fe(CN)6]
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Non-toxic K4[Fe(CN)6] was demonstrated to be effective as a green cyanating agent for the cyanation of alkyl halides using PPh3/Pd(OAc)2 as a catalyst system. The presented method allowed a series of benzyl chlorides to be smoothly cyanated in up to 88% yield. In order to avoid or suppress the deactivation of the catalyst, the reaction was required to be performed in a stringent inert ambiance.
- Ren, Yunlai,Yan, Mengjie,Zhao, Shuang,Sun, Yanpei,Wang, Jianji,Yin, Weiping,Liu, Zhifei
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scheme or table
p. 5107 - 5109
(2011/10/05)
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- Carboanion Reactivity: Kinetics of the Reactions of Benzyl Cyanide Anions with Aromatic Nitro-compounds
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Rate and equilibrium measurements are reported for the reactions in methanol of carbanions derived from 12 ring-substituted benzyl cyanides with 1,3,5-trinitrobenzene to give ?-adducts.Some data for reaction of the carbanions with 4-nitrobenzofuroxan were also measured.With increasing carbanion reactivity, rate constants approach a limit of just below 109 dm3 mol-1 s-1.Intrinsic reactivities of carbanions in ?-adduct forming reactions and in proton transfer reactions are compared.
- Atherton, John H.,Crampton, Michael R.,Duffield, Gaynor L.,Stevens, J. Andrew
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p. 443 - 448
(2007/10/02)
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- The Acidity of Weak Carbon Acids. Part 3. The Kinetic Acidities of Substituted Benzyl Cyanides using Secondary Aliphatic Amines and Guanidines as Bases
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The rate coefficients for the base-catalysed detritiation of a series of m-substituted benzyl cyanides in DMSO and methanol have been measured at 25.0 deg C.In DMSO the bases are a series of secondary aliphatic amines and guanidines and in methanolic methoxide.For benzyl cyanide and piperidine in DMSO, the rate coefficients for detritiation at 55.0 deg C and dedeuteration at 25.0 deg C were also measured.The kinetic isotope effect and activation parameters indicate the rate determining step to be the ionisation process.Broensted coefficients, α and δ, have been calculated from both the known pKa values of the substrates and measured pKa values of the bases in DMSO.Both indicate a transition state composed of an "advanced" carbanionic structure.There is no reactivity-selectivity relationship apparent.The results are discussed in relation to Marcus and related theories.
- Bowden, Keith,Madvi, Nighat S.,Ranson, Richard J.
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p. 2474 - 2496
(2007/10/02)
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- SYNTHESIS OF INDENES FROM PHENYLPROPANONES USING ALUMINA CATALYST
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1,3-Diphenylpropan-2-one undergoes dehydration over alumina at around 400 deg C to form 1,3-diphenylallene which cyclizes to 2-phenylindene.Since the parent ketone can be obtained under the reaction conditions from phenylacetic acid, the present reaction forms a one step syntheses of 2-phenylindene from phenylacetic acid. 3- and 4-methylphenylacetic acids also give the corresponding indenes. 1,3-Diphenylpropan-1-ones also give phenylindenes, presumably by a direct cyclodehydration reaction.
- Jayamani, M.,Pant, Nalin,Ananthan, S.,Narayanan, K.,Pillai, C. N.
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p. 4325 - 4332
(2007/10/02)
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- Photochemical Aromatic Cyanomethylation: Aromatic Substitution by Way of Radical Cations
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Photolysis at 254 nm of chloroacetonitrile in the presence of aromatic hydrocarbons led to ring cyanomethylation.In addition radical coupling products were found, especially with toluene where 3-phenylpropionitrile, succinonitrile, and bibenzyl accompanied the tolylacetonitriles.These same byproducts were obtained from toluene and chloroacetonitrile upon thermolysis with peroxide initiators, but no nuclear cyanomethylation was observed.The mechanism for aromatic cyanomethylation involves initial excitation of the aromatic hydrocarbons, followed by an electron transfer (probably by way of an exiplex) to chloroacetonitrile, which was found to quench aromatic fluorescence at high rates.Direct spectral evidence for the resulting radical cation with p-dimethoxybenzen was obtained by using flash laser spectroscopy.Loss of a chloride ion from the resulting radical anion produces a cyanomethyl radical in close proximity to an aromatic radical cation.Coupling leads to the aromatic substitution products whereas radicals escaping from the cage account for the observed byproducts.
- Kurz, M. E.,Lapin, S. C.,Miriam, K.,Hagen, T. J.,Qian, X. Q.
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p. 2728 - 2733
(2007/10/02)
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- PALLADIUM CATALYZED REACTION OF ARYL BROMIDES WITH CYANOMETHYLTRIBUTYLTIN. AROMATIC CYANOMETHYLATION
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Palladium catalyzed reaction of aryl bromides with cyanomethyltributyltin gave arylacetonitriles in moderate yields.Aryl bromides having strong electron-withdrawing groups (such as acyl, cyano, nitro, etc.) cannot be applied to the reaction.
- Kosugi, Masanori,Ishiguro, Masahiro,Negishi, Yoshikazu,Sano, Hiroshi,Migita, Toshihiko
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p. 1511 - 1512
(2007/10/02)
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- Photochemical Aromatic Cyanomethylation
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Cyanomethylation is accomplished by the photolysis of chloroacetonitrile in the presence of aromatics by way of electron transfer followed by radical coupling.
- Lapin, Stephen,Kurz, Michael E.
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p. 817 - 818
(2007/10/02)
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