- Mechanochemical synthesis of half-sandwich iridium/rhodium complexes with 8-hydroxyquinoline derivatives ligands
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Mechanochemistry provides a rapid, efficient route to half-sandwich iridium and rhodium complexes from [MCp*(μ-Cl)Cl]2 (M = Ir, Rh) and 8-hydroxyquinoline-2-carbaldehyde without the need for Schlenk manipulation, inert gas protection, or dry solvents. Furthermore, post-synthetic modification of the half-sandwich metal complexes has been carried out via a mechanochemical Wittig reaction between half-sandwich metal complex and phosphorus ylide. All complexes were fully characterized by 1H and 13C NMR spectra, infrared spectroscopy, mass spectrometry, and single-crystal X-ray diffraction method. The half-sandwich rhodium complexes exhibited high catalytic activity towards the amide synthesis between aldehyde and hydroxylamine hydrochloride (NH2OH·HCl) with a broad functional group tolerance.
- Jia, Wei-Guo,Li, Xiao-Dong,Zhi, Xue-Ting,Zhong, Rui
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- Hydration of Aliphatic Nitriles Catalyzed by an Osmium Polyhydride: Evidence for an Alternative Mechanism
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The hexahydride OsH6(PiPr3)2 competently catalyzes the hydration of aliphatic nitriles to amides. The main metal species under the catalytic conditions are the trihydride osmium(IV) amidate derivatives OsH3{κ2-N,O-[HNC(O)R]}(PiPr3)2, which have been isolated and fully characterized for R = iPr and tBu. The rate of hydration is proportional to the concentrations of the catalyst precursor, nitrile, and water. When these experimental findings and density functional theory calculations are combined, the mechanism of catalysis has been established. Complexes OsH3{κ2-N,O-[HNC(O)R]}(PiPr3)2 dissociate the carbonyl group of the chelate to afford κ1-N-amidate derivatives, which coordinate the nitrile. The subsequent attack of an external water molecule to both the C(sp) atom of the nitrile and the N atom of the amidate affords the amide and regenerates the κ1-N-amidate catalysts. The attack is concerted and takes place through a cyclic six-membered transition state, which involves Cnitrile···O-H···Namidate interactions. Before the attack, the free carbonyl group of the κ1-N-amidate ligand fixes the water molecule in the vicinity of the C(sp) atom of the nitrile.
- Babón, Juan C.,Esteruelas, Miguel A.,López, Ana M.,O?ate, Enrique
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p. 7284 - 7296
(2021/05/29)
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- Manganese-Pincer-Catalyzed Nitrile Hydration, α-Deuteration, and α-Deuterated Amide Formation via Metal Ligand Cooperation
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A simple and efficient system for the hydration and α-deuteration of nitriles to form amides, α-deuterated nitriles, and α-deuterated amides catalyzed by a single pincer complex of the earth-abundant manganese capable of metal-ligand cooperation is reported. The reaction is selective and tolerates a wide range of functional groups, giving the corresponding amides in moderate to good yields. Changing the solvent from tert-butanol to toluene and using D2O results in formation of α-deuterated nitriles in high selectivity. Moreover, α-deuterated amides can be obtained in one step directly from nitriles and D2O in THF. Preliminary mechanistic studies suggest the transformations contributing toward activation of the nitriles via a metal-ligand cooperative pathway, generating the manganese ketimido and enamido pincer complexes as the key intermediates for further transformations.
- Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Milstein, David,Zhou, Quan-Quan,Zou, You-Quan
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p. 10239 - 10245
(2021/08/24)
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- Amide bond formation in aqueous solution: Direct coupling of metal carboxylate salts with ammonium salts at room temperature
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Herein, we report a green, expeditious, and practically simple protocol for direct coupling of carboxylate salts and ammonium salts under ACN/H2O conditions at room temperature without the addition of tertiary amine bases. The water-soluble coupling reagent EDC·HCl is a key component in the reaction. The reaction runs smoothly with unsubstituted/substituted ammonium salts and provides a clean product without column chromatography. Our reaction tolerates both carboxylate (which are unstable in other forms) and amine salts (which are unstable/volatile when present in free form). We believe that the reported method could be used as an alternative and suitable method at the laboratory and industrial scales. This journal is
- Nielsen, John,Tung, Truong Thanh
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supporting information
p. 10073 - 10080
(2021/12/10)
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- Efficient heterogeneous hydroaminocarbonylation of olefins with ammonium chloride as amino source
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An efficient protocol for heterogeneous hydroaminocarbonylation of olefins with ammonium chloride without addition of acid additive has been developed for the first time. We successfully synthesized the Pd@POPs-PPh3 catalyst through a solvothermal synthetic method. Under this heterogeneous catalytic system, C2-C6 olefins displayed good yields and TON, and a yield of 66% of propionamide and TON = 1400 were obtained under mild reaction conditions (403 K, Pethylene = 0.5 MPa, PCO = 2.5 MPa), which is a little higher than those in the homogeneous system. This catalytic system has the advantage of easy separation of product and catalyst, as well as good stability. Uniform dispersion of Pd active sites, strong coordination bond between P and Pd, high surface area, large pore volume and hierarchical porosity of Pd@POPs-PPh3 were confirmed by a series of characterizations, which is believed to be the keys for the good activity and stability of hydroaminocarbonylation reaction.
- Sun, Zhao,Yan, Li,Ji, Guangjun,Wang, Guoqing,Ma, Lei,Jiang, Miao,Li, Cunyao,Ding, Yunjie
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- Half-Sandwich Iridium Complexes Based on β-Ketoamino Ligands: Preparation, Structure, and Catalytic Activity in Amide Synthesis
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A series of β-ketoamino-based N,O-chelate half-sandwich iridium complexes with the general formula [Cp*IrClL] have been prepared in good yields. These air-insensitive iridium complexes showed desirable catalytic activity in an amide preparation under mild conditions. A number of amides with diverse substituted groups were furnished in a one-pot reaction with good-to-excellent yields through an amidation reaction of NH2OH·HCl with aldehydes in the presence of these iridium(III) precursors. The excellent catalytic activity, mild reaction conditions, and broad substrate scope gave this type of iridium catalyst potential for use in industry. All of the obtained iridium complexes were well characterized by different spectroscopy techniques. The exact molecular structure of complex 3 has been confirmed by single-crystal X-ray analysis.
- Wang, Yang,Guo, Wen,Guan, Ai-Lin,Liu, Shuang,Yao, Zi-Jian
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p. 11514 - 11520
(2021/07/31)
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- Sustainable hydrogenation of aliphatic acyclic primary amides to primary amines with recyclable heterogeneous ruthenium-tungsten catalysts
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The hydrogenation of amides is a straightforward method to produce (possibly bio-based) amines. However current amide hydrogenation catalysts have only been validated in a rather limited range of toxic solvents and the hydrogenation of aliphatic (acyclic) primary amides has rarely been investigated. Here, we report the use of a new and relatively cheap ruthenium-tungsten bimetallic catalyst in the green and benign solvent cyclopentyl methyl ether (CPME). Besides the effect of the Lewis acid promotor, NH3 partial pressure is identified as the key parameter leading to high primary amine yields. In our model reaction with hexanamide, yields of up to 83% hexylamine could be achieved. Beside the NH3 partial pressure, we investigated the effect of the catalyst support, PGM-Lewis acid ratio, H2 pressure, temperature, solvent tolerance and product stability. Finally, the catalyst was characterized and proven to be very stable and highly suitable for the hydrogenation of a broad range of amides.
- Coeck, Robin,Berden, Sarah,De Vos, Dirk E.
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supporting information
p. 5326 - 5335
(2019/10/11)
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- Appraisal of Ruthenium(II)complexes of (4-phenoxyphenylazo)ligands for the synthesis of primary amides by dint of hydroxylamine hydrochloride and aldehydes
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A new family of O, N donor-functionalized (4-phenoxyphenylazo)-2-naphthol/4-substituted phenol-based ligands (HL1-HL4)has been synthesized. The prepared ligands were successfully utilized for the access of a series of ruthenium(II)carbonyl complexes of the type [Ru(L)Cl(CO)(EPh3)3](E = phosphine/arsine), (L = 1-(4-phenoxyphenylazo)-2-naphthol (HL1), 2-(4-phenoxyphenylazo)-4-chlorophenol (HL2), 2-(4-phenoxyphenylazo)-4-methylphenol (HL3)and 2-(4-phenoxyphenylazo)-4-methoxyphenol (HL4)). All of the ruthenium(II)carbonyl complexes and ligands have been fully characterized by FT-IR, UV–visible, 1H NMR, 31P NMR, mass spectrometry and CHN analysis. The ligands have been analyzed by 13C NMR. The UV–visible spectroscopic study reveals that both the ligands and Ru(II)complexes exhibit excellent charge transfer transitions. This is the basic criteria for the oxidative amidation reaction, which is an influential strategy for the transformation of oxygenated organic compounds to the profitable amides. However, this catalytic process makes more impact on the application of new divalent ruthenium(II)azo compounds as catalyst in a single-pot conversion of aldehydes to amides in the presence of NaHCO3.
- Vinoth, Govindasamy,Indira, Sekar,Bharathi, Madheswaran,Sounthararajan, Muniyan,Sakthi, Dharmalingam,Bharathi, Kuppannan Shanmuga
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- Water-soluble superbulky (η6- p -cymene) ruthenium(ii) amine: An active catalyst in the oxidative homocoupling of arylboronic acids and the hydration of organonitriles
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A phosphine free water-soluble superbulky amine-ruthenium-arene complex (2) encompassing 2,6-bis(diphenylmethyl)-4-methylaniline was synthesised in good yield. 2 was characterized by FT-IR, 1H NMR, and 13C NMR spectroscopies, TGA and elemental analyses. The structure of 2 was confirmed by a single-crystal X-ray diffraction study. The ruthenium centre in 2 adopts the pseudo-octahedral geometry due to the η6-p-cymene ring and bulky aniline ligand along with two chloro groups. Besides, complex 2 was efficaciously employed as a catalyst in the hydration of organonitriles to amides. This reaction proceeds efficiently for a wide range of substrates in an environmentally benign medium and is an economically reasonable synthetic route to amides in good yields. In addition, 2 acts as an excellent catalyst in the oxidative homocoupling of arylboronic acids in water. A range of arylboronic acids undergo a homocoupling reaction in the presence of catalyst 2 to yield symmetrical biaryls in reasonable to good yields.
- Nirmala, Muthukumaran,Adinarayana, Mannem,Ramesh, Karupnaswamy,Maruthupandi, Mannarsamy,Vaddamanu, Moulali,Raju, Gembali,Prabusankar, Ganesan
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supporting information
p. 15221 - 15230
(2018/09/29)
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- Palladium-catalyzed regiodivergent hydroaminocarbonylation of alkenes to primary amides with ammonium chloride
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Palladium-catalyzed hydroaminocarbonylation of alkenes for the synthesis of primary amides has long been an elusive aim. Here, we report an efficient catalytic system which enables inexpensive NH4Cl to be utilized as a practical alternative to gaseous ammonia for the palladium-catalyzed alkene-hydroaminocarbonylation reaction. Through appropriate choice of the palladium precursors and ligands, either branched or linear primary amides can be obtained in good yields with good to excellent regioselectivities. Primary mechanistic studies were conducted and disclosed that electrophilic acylpalladium species were capable of capturing the NH2-moiety from ammonium salts to form amides in the presence of CO with NMP as a base.
- Gao, Bao,Zhang, Guoying,Zhou, Xibing,Huang, Hanmin
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p. 380 - 386
(2018/01/12)
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- Controlled photocatalytic hydrolysis of nitriles to amides by mesoporous MnO2 nanoparticles fabricated by mixed surfactant mediated approach
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The solid-phase MnO2 nanoparticles fabricated by surfactant template method were exploited as the photocatalyst for the effective one-step synthesis of amides. Cationic or anionic surfactants and their combinations were used as porous templates to obtain the mesoporous MnO2 nanoparticles with variable pore volume (0.23–1.95?cm3/g). The morphological and structural observation of the material confirms the uniform facet structure (37.68?nm) of MnO2 nanoparticles. The surface elemental state was confirmed by XPS analysis confirming Mn 2p3/2 (642.5?eV) and Mn2p1/2 (654.7?eV) spin states, that are common for the tetravalent Mn ions. Presence of surfactant as stabilizer was also witnessed with a strong peak of C 1s (283–286?eV). The textural parameters obtained from XRD and Raman analysis depicted the β-phase and rutile type framework of MnO2. The selective conversion of nitriles to amides was studied without any acid by products under visible light irradiation in the basic/neutral medium. Amides were obtained from various substrates (nitriles) with excellent yields (70–90%).
- Mehta, Akansha,Basu, Soumen
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- A selective hydration of nitriles catalysed by a Pd(OAc)2-based system in water
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In situ formation of a [Pd(OAc)2bipy] (bipy = 2,2′-bipyridyl) complex in water selectively catalyses the hydration of a wide range of organonitriles at 70 °C. Catalyst loadings of 5 mol% afford primary amide products in excellent yields in the absence of hydration-promoting additives such as oximes and hydroxylamines.
- Sanz Sharley, Daniel D.,Williams, Jonathan M.J.
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supporting information
p. 4090 - 4093
(2017/09/27)
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- Mixed-valence μ3-oxo-centered triruthenium cluster [Ru3(II,III,III)(μ3-O)(μ-CH3CO2)6(H2O)3]·2H2O: Synthesis, structural characterization, valence-state delocalization and catalytic behavior
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The oxo-centered, trinuclear, mixed valence [Ru3(II,III,III)O(CH3CO2)6(H2O)3]·2H2O (2) acetate complex has been prepared with high yield through reduction of [Ru3(III,III,III)O(CH3CO2)6(CH3OH)3]·CH3CO2precursor compound in presence of muccic acid under hydrothermal conditions. The crystalline trinuclear oxo-cluster has been obtained as crystalline powder and characterized by single-crystal and powder X-ray diffraction, elemental analysis, SEM, TGA, IR spectroscopy. Complex 2 composes of μ3-oxocentered trinuclear ruthenium array and exhibits the oxidation state delocalization between three Ru atoms at 293 K. Accurate single-crystal analysis along with valence bond calculations reveal trapped-valence state delocalization at room temperature, whereas three-site relaxation occurs at 100 K leading to Ru(II) and Ru2(III) formal states. Moreover, the mixed valence of RuIIRu2IIIunit in compound 2 has been confirmed by XANES spectroscopy. The catalytic behavior of oxo-centered triruthenium complex 2 has been examined in hydration of nitriles and isomerization of allylic alcohols reactions both realized in aqueous media.
- Dikhtiarenko, Alla,Khainakov, Sergei,García, José R.,Gimeno, José
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p. 107 - 116
(2016/11/19)
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- Method for preparing amide by metallic sodium catalyzed ester ammonolysis reaction
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The invention discloses a method for preparing amide by metallic sodium catalyzed ester ammonolysis reaction. The method is characterized in that ester and liquid ammonia are taken as raw materials, and metallic sodium is taken as a catalyst to perform reaction at a temperature of 90-140 DEG C in a high-pressure kettle; a molar ratio of the ester to ammonium is 1: (1.2 to 5.0); molar weight of the metallic sodium is 4-10% that of the ester; when reaction pressure is not lowered any longer, reaction is stopped to recycle the ammonium which is not reacted; and an obtained reaction product is post-treated to obtain a product. The method can be used for efficiently preparing the amide; and moreover, the raw materials are cheap and are low in toxicity, reaction activity is relatively high, dose of the catalyst is small, reaction speed is high, a reaction conversion rate is high, and the product is easily separated.
- -
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Paragraph 0066
(2017/08/30)
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- Mechanistic Investigations of Reactions of the Frustrated Lewis Pairs (Triarylphosphines/B(C6F5)3) with Michael Acceptors
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Frustrated Lewis pair (FLP)-catalyzed reduction of Michael acceptors is a challenging reaction that proceeds with specific FLP structures. Kinetics and equilibrium of the reactions of two phosphines (Ar3P), namely tri(1-naphthyl)phosphine and tri(o-tolyl)phosphine, are reported with reference electrophiles. The reason for the failure of the FLPs (Ar3P/B(C6F5)3) to reduce activated alkenes under H2 pressure is shown to be a hydrophosphination process that inhibits the reduction reaction. Kinetic and thermodynamic factors controlling both pathways are discussed in light of Mayr's free linear energy relationships.
- Dupré, Jonathan,Gaumont, Annie-Claude,Lakhdar, Sami
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supporting information
p. 694 - 697
(2017/02/10)
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- Palladium/Phosphorus-Doped Porous Organic Polymer as Recyclable Chemoselective and Efficient Hydrogenation Catalyst under Ambient Conditions
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A new type of phosphorus-doped porous organic polymer (POP) has been readily synthesized through a Heck reaction, which could be used not only as a support but also a ligand for palladium nanoparticles. The dual-functional material supported palladium nanocatalyst was used for the efficient and chemoselective hydrogenation of varieties of nitroarenes and α,β-unsaturated compounds, as well as for the synthesis of indoles from 2-nitrophenylacetonitrile under 1 atm hydrogen in green solvents at room temperature. No obvious aggregation and loss of catalytic activity of the new nanocatalyst were observed after 10 runs in the reaction. (Figure presented.).
- Ding, Zong-Cang,Li, Cun-Yao,Chen, Jun-Jia,Zeng, Jia-Hao,Tang, Hai-Tao,Ding, Yun-Jie,Zhan, Zhuang-Ping
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p. 2280 - 2287
(2017/07/07)
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- A mild hydration of nitriles catalysed by copper(ii) acetate
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A simple, mild and general procedure for the hydration of nitriles to amides using copper as catalyst and promoted by N,N-diethylhydroxylamine is described. The reaction can be conducted in water at low temperature in short reaction times. This new procedure allows amides to be obtained from a wide range of substrates in excellent yields.
- Marcé, Patricia,Lynch, James,Blacker, A. John,Williams, Jonathan M. J.
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supporting information
p. 1436 - 1438
(2016/01/25)
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- Supported Gold Nanoparticles-Catalyzed Microwave-Assisted Hydration of Nitriles to Amides under Base-Free Conditions
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Polystyrene-supported gold (Au@PS) nanoparticles were synthesized by the reduction deposition approach and well characterized by UV-visible, XRD, TEM, SAED, EDX, and XPS studies. The Au@PS was applied as catalyst for the hydration of nitriles to amides in water under microwave irradiation. Several functionalized aromatic, heterocyclic and aliphatic nitriles were found to be active for synthesis of the corresponding amides where no activation of water by base, ligand and support is needed. Easy recovery, negligible leaching and recyclability for up to eight runs are added advantages of the catalyst under water-mediated reaction conditions. (Figure presented.).
- Kumar, Sandeep,Sharma, Saurabh,Das, Pralay
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supporting information
p. 2889 - 2894
(2016/09/16)
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- MANUFACTURING METHOD OF AMIDE COMPOUND, ALLOY PARTICLE AND CATALYST CONTAINING THE SAME
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PROBLEM TO BE SOLVED: To provide an alloy particle for a catalyst capable of manufacturing an amide compound with high efficiency and capable of manufacturing the amide compound at low cost easily on an industrial scale. SOLUTION: There is provided an alloy particle for catalyst used in manufacturing an amide compound having a B2 type or L12 type crystal structure constituted by Cu and Pd or a L10 type crystal structure constituted by Cu and Au and having average particle diameter of the alloy particle of 1 to 200 nm. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2016,JPO&INPIT
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Paragraph 0147
(2017/03/23)
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- Ruthenium(II) complexes incorporating salicylaldiminato-functionalized N-heterocyclic carbene ligands as efficient and versatile catalysts for hydration of organonitriles
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We describe a new synthetic procedure for synthesis of ruthenium(II) complexes containing salicylaldiminato functionalized mixed N-heterocyclic carbene (NHC) ligand and phosphine co-ligand. The complexes (3a-3d) have been obtained in good to excellent yields by transmetalation from the corresponding Ag-NHC complexes (2a-2d) as carbene transfer reagents. All the [Ru-NHC] complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. The ligands 1a-1d show their versatility by switching to be O,N,C-chelating in these ruthenium(II) complexes. The resulting complexes have been evaluated as potential catalysts for the selective hydration of nitriles to primary amides, and related amide bond forming reactions, in environmentally friendly medium. The reaction tolerated ether, hydroxyl, nitro, bromo, formyl, pyridyl, benzyl and alkyl functional groups. The catalyst was stable for weeks and could be recovered and reused more than six times without significant loss of activity.
- Nirmala, Muthukumaran,Saranya, Gandhi,Viswanathamurthi, Periasamy
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p. 134 - 144
(2016/01/09)
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- Transfer Hydrogenation of Nitriles, Olefins, and N-Heterocycles Catalyzed by an N-Heterocyclic Carbene-Supported Half-Sandwich Complex of Ruthenium
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In the presence of KOBut, N-heterocyclic carbene-supported half-sandwich complex [Cp(IPr)Ru(pyr)2][PF6] (3) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) catalyzes transfer hydrogenation (TH) of nitriles, activated N-heterocycles, olefins, and conjugated olefins in isopropanol at the catalyst loading of 0.5%. The TH of nitriles leads to imines, produced as a result of coupling of the initially formed amines with acetone (produced from isopropanol), and showed good chemoselectivity. Reduction of N-heterocycles occurs for activated polycyclic substrates (e.g., quinoline) and takes place exclusively in the heterocycle. The TH also works well for linear and cyclic olefins but fails for trisubstituted substrates. However, the C = C bond of α,β-unsaturated esters, amides, and acids is easily reduced even for trisubstituted species, such as isovaleriates. Mechanistic studies suggest that the active species in these catalytic reactions is the trihydride Cp(IPr)RuH3 (5), which can catalyze these reactions in the absence of any base. Kinetic studies are consistent with a classical inner sphere hydride-based mechanism of TH.
- Mai, Van Hung,Nikonov, Georgii I.
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p. 943 - 949
(2016/05/09)
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- Conversion of nitroalkanes into carboxylic acids via iodide catalysis in water
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We report a new method for the conversion of nitroalkanes into carboxylic acids that achieves this transformation under very mild conditions. Catalytic amounts of iodide in combination with a simple zinc catalyst are needed to give good conversions into the corresponding carboxylic acids.
- Marcé, Patricia,Lynch, James,Blacker, A. John,Williams, Jonathan M. J.
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supporting information
p. 1013 - 1016
(2016/01/16)
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- Selective Hydration of Nitriles to Amides Over Titania Supported Palladium Exchanged Vanadium Incorporated Molybdophosphoric Acid Catalysts
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Abstract: Titania supported palladium exchanged vanadium incorporated molybdophosphoric acid (PdMPAV1) catalysts were prepared and characterized by FT-IR, X-ray diffraction and Laser Raman spectroscopy. The characterization results confirmed the presence of vanadium and palladium into the primary and secondary structure of Keggin ion of heteropoly molybdate respectively. The PdMPAV1 was dispersed on support with intact Keggin ion structure. These catalysts were studied for selective hydration of nitriles to amides. The PdMPAV1was highly active compared to the molybdophosphoric acid containing either vanadium or palladium. The catalyst with 20?% PdMPAV1 dispersed on TiO2 showed highest activity compare to other catalysts. A variety of nitriles were tested over this catalyst and found that the catalyst was active to yield corresponding amides. Different reaction parameters were studied and optimum conditions were established. The PdMPAV1/TiO2 catalyst exhibited consistent activity during reuse. Graphical Abstract: [Figure not available: see fulltext.]
- Srinivasa Rao,Srivani,Dhana Lakshmi,Lingaiah
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p. 2025 - 2031
(2016/10/18)
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- Selective aerobic hydrolysis of nitriles to amides using cobalt(II)/zinc
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A novel protocol has been developed for the aerobic hydrolysis of nitriles to amides using cobalt(II)/zinc without using any strong acids and bases under solvent-free conditions. The reaction showed good performance for benzonitriles with sensitive groups such as ester and carboxylic acid.
- Keshipour, Sajjad,Shaabani, Ahmad
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p. 5071 - 5078
(2015/07/08)
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- Direct oxidative esterification of alcohols and hydration of nitriles catalyzed by a reusable silver nanoparticle grafted onto mesoporous polymelamine formaldehyde (AgNPs@mPMF)
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A nitrogen-rich mesoporous organic polymer was synthesized as a novel support. A silver nanoparticle was synthesized and grafted onto it. The prepared catalyst (AgNPs@mPMF) was characterized by powder X-ray diffraction (XRD), scanning electron microscopy(SEM) and energy dispersive X-ray spectrometry (EDS), thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS), N2 adsorption, Raman spectroscopy and EPR study. The catalytic activity was evaluated for the oxidative esterification reaction of alcohols and hydration of nitriles. The oxidative esterification reaction was carried out for various activated alcohols giving excellent yields of the corresponding ester products. The catalyst was also efficient in the hydration of nitriles. Both reactions were optimized by varying the bases, temperatures and solvents. The catalyst can be facilely recovered and reused six times without a significant decrease in its activity and selectivity.
- Ghosh, Kajari,Iqubal, Md. Asif,Molla, Rostam Ali,Mishra, Ashutosh,Kamaluddin,Islam, Sk Manirul
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p. 1606 - 1622
(2015/04/27)
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- Hydration of nitriles to amides by a chitin-supported ruthenium catalyst
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Chitin-supported ruthenium (Ru/chitin) promotes the hydration of nitriles to carboxamides under aqueous conditions. The nitrile hydration can be performed on a gram-scale and is compatible with the presence of various functional groups including olefins, aldehydes, carboxylic esters and nitro and benzyloxycarbonyl groups. The Ru/chitin catalyst is easily prepared from commercially available chitin, ruthenium(III) chloride and sodium borohydride. Analysis of Ru/chitin by high-resolution transmission electron microscopy indicates the presence of ruthenium nanoparticles on the chitin support.
- Matsuoka, Aki,Isogawa, Takahiro,Morioka, Yuna,Knappett, Benjamin R.,Wheatley, Andrew E. H.,Saito, Susumu,Naka, Hiroshi
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p. 12152 - 12160
(2015/02/19)
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- Ruthenium(II) carbonyl complexes containing pyridoxal thiosemicarbazone and trans-bis(triphenylphosphine/arsine): Synthesis, structure and their recyclable catalysis of nitriles to amides and synthesis of imidazolines
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Pyridoxal N(4)-substituted thisemicarbazone hydrochloride ligands (L1-3) were synthesized and reacted with the ruthenium(II) starting complexes [RuHCl(CO)(EPh3)3] (EP or As). The resulting complexes [Ru(CO)(L1-3)(EPh3)2] (1-6) were characterized by elemental analyses and spectroscopic techniques. The molecular structure of complex 5 was identified by means of single crystal X-ray diffraction analysis. The catalytic activity of the new complexes was evaluated for the selective hydration of nitriles to primary amides and also the condensation of nitriles with ethylenediamine under solvent free conditions. The processes were operative with aromatic, heteroaromatic and aliphatic nitriles, and tolerated several substitutional groups. The studies on the effect of substitution over thiosemicarbazone, reaction time, temperature, solvent and catalyst loading were carried out in order to find the best catalyst in this series of complexes and favourable reaction conditions. A probable mechanism for both the catalytic reactions of nitrile has also been proposed. The catalyst was recovered and recycled in the hydration of nitriles for five times without any significant loss of its activity.
- Manikandan, Rajendran,Anitha, Panneerselvam,Prakash, Govindan,Vijayan, Paranthaman,Viswanathamurthi, Periasamy,Butcher, Ray Jay,Malecki, Jan Grzegorz
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p. 312 - 324
(2015/01/30)
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- Rhodium-Mediated Oxygenation of Nitriles with Dioxygen: Isolation of Rhodium Derivatives of Peroxyimidic Acids
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Dioxygen is used as the oxygenation agent in the rhodium-mediated conversion of nitriles into amides. The characterization of intermediate species and model compounds as well as isotope-labeling studies provided an insight into the reaction mechanism. The conversions of rhodium hydroperoxido or methylperoxido complexes with nitriles into metallacyclic rhodium- κ2-(N,O)-peroxyimidate compounds represent essential key steps. The former are accessible from a rhodium(III) peroxido complex and the latter represent rhodium derivatives of Payne's reagent (peroxyimidic acids).
- Bittner, Annemarie,Braun, Thomas,Herrmann, Roy,Mebs, Stefan
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supporting information
p. 12299 - 12302
(2015/08/25)
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- Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes
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An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.
- Qureshi, Ziyauddin S.,Sarawade, Pradip B.,Albert, Matthias,D'Elia, Valerio,Hedhili, Mohamed N.,K?hler, Klaus,Basset, Jean-Marie
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p. 635 - 642
(2015/03/05)
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- Highly efficient and chemoselective hydrogenation of α,β-unsaturated carbonyls over Pd/N-doped hierarchically porous carbon
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Palladium nanoparticles supported on N-doped hierarchically porous carbon, Pd/CNx, has been developed as a highly efficient, reusable and environmentally benign heterogeneous catalyst for the selective hydrogenation of various α,β-unsaturated carbonyls to their corresponding saturated carbonyls under mild conditions (303 K, 1 bar H2). Complete conversion of a series of α,β-unsaturated carbonyls was achieved with excellent selectivity (>99%) within 4 h. Moreover, the catalyst can be easily recovered by centrifugation and withstands recycling up to 8 times without apparent loss of activity and selectivity. The considerable catalytic performance is attributed to the hierarchically porous network and incorporation of nitrogen atoms. This catalytic system opens up an efficient, selective, recyclable and sustainable method for selective hydrogenation.
- Wei, Zhongzhe,Gong, Yutong,Xiong, Tianyi,Zhang, Pengfei,Li, Haoran,Wang, Yong
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p. 397 - 404
(2015/02/02)
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- Mild and selective heterogeneous catalytic hydration of nitriles to amides by flowing through manganese dioxide
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A sustainable flow chemistry process for the hydration of nitriles, whereby an aqueous solution of the nitrile is passed through a column containing commercially available amorphous manganese dioxide, has been developed. The product is obtained simply by concentration of the output stream without any other workup steps. The protocol described is rapid, robust, reliable, and scalable, and it has been applied to a broad range of substrates, showing a high level of chemical tolerance.
- Battilocchio, Claudio,Hawkins, Joel M.,Ley, Steven V.
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supporting information
p. 1060 - 1063
(2016/10/17)
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- Ag-grafted covalent imine network material for one-pot three-component coupling and hydration of nitriles to amides in aqueous medium
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A nitrogen rich porous covalent imine network material (CIN-1) has been successfully employed for grafting silver nanoparticles (Ag NPs). The Ag NPs grafted CIN-1, Ag-CIN-1 has been characterized by elemental analysis, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and EPR spectroscopic studies. Ag-CIN-1 acts as a truly heterogeneous catalyst in the hydration of nitriles to amides and the A3 coupling reactions between the alkyne, amine and aldehyde to produce propargylamines by using water as a green solvent. This journal is
- Salam, Noor,Kundu, Sudipta K.,Molla, Rostam Ali,Mondal, Paramita,Bhaumik, Asim,Islam, Sk. Manirul
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p. 47593 - 47604
(2015/02/19)
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- One-pot synthesis of 2-alkyl-4(5)-aryl-1H-imidazoles from 1-aryl-2-bromoethanones, ammonium carbonate and aliphatic carboxylic acids
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A simple and efficient protocol for the preparation of 2-alkyl-4(5)-aryl- 1H-imidazoles starting from α-bromo aryl methyl ketones and aliphatic carboxylic acids in the presence of ammonium carbonate has been developed.
- Liu, Cong,Nie, Yijiao,Yao, Guowei,Dai, Rongji,Deng, Yulin
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p. 208 - 210
(2014/05/06)
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- High-temperature synthesis of amides from alcohols or aldehydes by using flow chemistry
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An efficient conversion of aliphatic and aromatic alcohols or aldehydes into the corresponding primary amides was successfully achieved by using flow chemistry. Excellent yields were obtained in very short reaction times, and thus this method offers an efficient alternative to traditional methods for amide formation.
- Ambreen, Nida,Wirth, Thomas
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p. 7590 - 7593
(2015/04/22)
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- Organic synthesis via magnetic attraction: Benign and sustainable protocols using magnetic nanoferrites
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Magnetic nano-catalysts have been prepared using simple modification of iron ferrites. The nm size range of these particles facilitates the catalysis process, as an increased surface area is available for the reaction; the easy separation of the catalysts by an external magnet and their recovery and reuse are additional beneficial attributes. Glutathione bearing nano-ferrites have been used as organocatalysts for the Paal-Knorr reaction and homocoupling of boronic acids. Nanoferrites, post-synthetically modified by ligands, were used to immobilize nanometals (Cu, Pd, Ru, etc.) which enabled the development of efficient, sustainable and green procedures for azide-alkynes-cycloaddition (AAC) reactions, C-S coupling, O-allylation of phenol, Heck-type reactions and hydration of nitriles.
- Nasir Baig,Varma, Rajender S.
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p. 398 - 417
(2013/03/14)
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- Solid-supported ruthenium(0): An efficient heterogeneous catalyst for hydration of nitriles to amides under microwave irradiation
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Solid-supported ruthenium(0) was synthesized by the reduction deposition method and used as a heterogeneous catalyst for the hydration of nitriles to amides under microwave irradiation. A wide range of aromatic, α,β-unsaturated and aliphatic nitriles were efficiently converted to their corresponding primary amides under milder conditions. The catalyst was found to be very stable under moisture and microwave irradiation, easily separable from the reaction mixture, to cause negligible metal contamination of the product and was recyclable up to ten times without significant loss of catalytic activity.
- Kumar, Sandeep,Das, Pralay
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supporting information
p. 2987 - 2990
(2013/10/01)
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- Transition metal-free 1,3-dimethylimidazolium hydrogen carbonate catalyzed hydration of organonitriles to amides
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An efficient hydration of organonitriles to the corresponding amides was accomplished using 1,3-dimethylimidazolium hydrogen carbonate as an organocatalyst. The developed catalytic method was also applicable for the synthesis of metal phthalocyanines.
- Verma, Praveen Kumar,Sharma, Upendra,Bala, Manju,Kumar, Neeraj,Singh, Bikram
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p. 895 - 899
(2013/04/23)
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- Catalytic nitrile hydration with [Ru(η6- p -cymene)Cl 2(PR2R′)] complexes: Secondary coordination sphere effects with phosphine oxide and phosphinite ligands
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The rates of nitrile hydration reactions were investigated using [Ru(η6-p-cymene)Cl2(PR2R′)] complexes as homogeneous catalysts, where PR2R′ = PMe 2(CH2P(O)Me2), PMe2(CH 2CH2P(O)Me2), PPh2(CH 2P(O)Ph2), PPh2(CH2CH 2P(O)Ph2), PMe2OH, P(OEt)2OH. These catalysts were studied because the rate of the nitrile-to-amide hydration reaction was hypothesized to be affected by the position of the hydrogen bond accepting group in the secondary coordination sphere of the catalyst. Experiments showed that the rate of nitrile hydration was fastest when using [Ru(η6-p-cymene)Cl2PMe2OH]: i.e., the catalyst with the hydrogen bond accepting group capable of forming the most stable ring in the transition state of the rate-limiting step. This catalyst is also active at pH 3.5 and at low temperatures - conditions where α-hydroxynitriles (cyanohydrins) produce less cyanide, a known poison for organometallic nitrile hydration catalysts. The [Ru(η6-p-cymene) Cl2PMe2OH] catalyst completely converts the cyanohydrins glycolonitrile and lactonitrile to their corresponding α-hydroxyamides faster than previously investigated catalysts. [Ru(η6-p-cymene) Cl2PMe2OH] is not, however, a good catalyst for acetone cyanohydrin hydration, because it is susceptible to cyanide poisoning. Protecting the -OH group of acetone cyanohydrin was shown to be an effective way to prevent cyanide poisoning, resulting in quantitative hydration of acetone cyanohydrin acetate.
- Knapp, Spring Melody M.,Sherbow, Tobias J.,Yelle, Robert B.,Juliette, J. Jerrick,Tyler, David R.
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p. 3744 - 3752
(2013/07/26)
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- A general and practical oxidation of alcohols to primary amides under metal-free conditions
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A general procedure for oxidation of both benzyl alcohols and alkyl alcohols to primary amides under catalyst free conditions has been developed. 34 examples of primary amides were produced from their corresponding alcohols in moderate to excellent yields. This is a practical procedure for primary amides synthesis; water and tert-butanol are the only by-products. A commercial drug, Piracetam, was prepared in one step with 73% yield as well.
- Wu, Xiao-Feng,Sharif, Muhammad,Feng, Jian-Bo,Neumann, Helfried,Pews-Davtyan, Anahit,Langer, Peter,Beller, Matthias
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p. 1956 - 1961
(2013/09/24)
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- Conversion of aldoximes into nitriles and amides under mild conditions
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A series of Pd(en)X2 salts were used as catalysts for the conversion of aldoximes into nitriles and amides. Highlights of this protocol include the use of inexpensive polar solvents, including water, and moderate reaction temperatures. A high degree of selectivity in the reaction outcome was observed when using aliphatic vs. aromatic/conjugated aldoximes. The Royal Society of Chemistry 2013.
- Tambara, Koujiro,Pantos, G. Dan
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supporting information
p. 2466 - 2472
(2013/06/05)
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- LRRK2 INHIBITORS
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Provided herein are compounds that inhibit or partially inhibit the activity of leucine rich repeat kinases. Also provided herein are methods of treatment of CNS disorders comprising administration of inhibitors of leucine rich repeat kinases.
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Page/Page column 123-124
(2013/02/28)
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- Bifunctional water activation for catalytic hydration of organonitriles
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Treatment of [Rh(COD)(μ-Cl)]2 with excess tBuOK and subsequent addition of 2 equiv of PIN?HBr in THF afforded [Rh(COD)(κC2-PIN)Br] (1) (PIN = 1-isopropyl-3-(5,7-dimethyl-1, 8-naphthyrid-2-yl)imidazol-2-ylidene, COD = 1,5-cyclooctadiene). The X-ray structure of 1 confirms ligand coordination to "Rh(COD)Br" through the carbene carbon featuring an unbound naphthyridine. Compound 1 is shown to be an excellent catalyst for the hydration of a wide variety of organonitriles at ambient temperature, providing the corresponding organoamides. In general, smaller substrates gave higher yields compared with sterically bulky nitriles. A turnover frequency of 20 000 h-1 was achieved for the acrylonitrile. A similar Rh(I) catalyst without the naphthyridine appendage turned out to be inactive. DFT studies are undertaken to gain insight on the hydration mechanism. A 1:1 catalyst-water adduct was identified, which indicates that the naphthyridine group steers the catalytically relevant water molecule to the active metal site via double hydrogen-bonding interactions, providing significant entropic advantage to the hydration process. The calculated transition state (TS) reveals multicomponent cooperativity involving proton movement from the water to the naphthyridine nitrogen and a complementary interaction between the hydroxide and the nitrile carbon. Bifunctional water activation and cooperative proton migration are recognized as the key steps in the catalytic cycle.
- Daw, Prosenjit,Sinha, Arup,Rahaman, S. M. Wahidur,Dinda, Shrabani,Bera, Jitendra K.
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experimental part
p. 3790 - 3797
(2012/06/18)
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- Ruthenium-catalyzed rearrangement of aldoximes to primary amides in water
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The rearrangement of aldoximes to primary amides has been studied using the readily available arene-ruthenium(II) complex [RuCl2(η 6-C6Me6){P(NMe2)3}] (5 mol %) as catalyst. Reactions proceeded cleanly in pure water at 100 °C without the assistance of any cocatalyst, affording the desired amides in high yields (70-90%) after short reaction times (1-7 h). The process was operative with both aromatic, heteroaromatic, α,β-unsaturated, and aliphatic aldoximes and tolerated several functional groups. Reaction profiles and experiments using 18O-labeled water indicate that two different mechanisms are implicated in these transformations. In both of them, nitrile intermediates are initially formed by dehydration of the aldoximes. These intermediates are then hydrated to the corresponding amides by the action of a second molecule of aldoxime or water. A kinetic analysis of the rearrangement of benzaldoxime to benzamide is also discussed.
- Garcia-Alvarez, Rocio,Diaz-Alvarez, Alba E.,Borge, Javier,Crochet, Pascale,Cadierno, Victorio
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p. 6482 - 6490
(2012/10/30)
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- A heterogeneous catalytic method for the conversion of nitriles into amides using molecular sieves modified with copper(II)
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A heterogenous catalytic method is developed for the hydration of nitriles into amides with acetaldoxime. Copper(II) supported on 4 molecular sieves is an efficient catalyst for this reaction.
- Kiss, árpád,Hell, Zoltán
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experimental part
p. 6021 - 6023
(2011/11/28)
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- Natural kaolin supported sulfuric acid as an efficient catalyst for selective hydrolysis of nitriles to amides
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The natural kaolin supported sulfuric acid as an efficient catalyst for selective hydrolysis of nitriles to amides was investigated. The nitrile (4 mmol) was dissolved in water (10 mL) in the presence of kaolin and refluxed for 24 h. The crude product was extracted with ethyl acetate in 55-80% yields after completion of the reaction (monitored by TLC). Careful neutralization of all reaction mixtures were carried out to pH = 7 for exact monitoring of reaction for possible formation of carboxylic acid. The products were characterized by IR and 1H NMR spectroscopy and also their melting points are compared with authentic samples. The disappearance of one strong and sharp absorption band (CN stretching band), and the appearance of two NH2 stretching bands in 3370 and 3320 cm-1 and carboxamide stretching in 1650 cm-1 in the IR spectra, were evidence for the formation of primary amides.
- Gordi, Zinat,Eshghi, Hossein
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experimental part
p. 715 - 718
(2011/10/08)
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- An efficient and heterogeneous recyclable palladium catalyst for chemoselective conjugate reduction of α,β-unsaturated carbonyls in aqueous medium
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An highly efficient PS-Pd-NHC catalytic system has been developed for chemoselective conjugate reduction of α,β-unsaturated carbonyl compounds providing good to excellent conversion with remarkable chemoselectivity (up to 100%). The developed protocol is more advantageous due to use of HCOONa as hydrogen source, environmentally benign water as solvent and effective catalyst recyclability.
- Bagal, Dattatraya B.,Qureshi, Ziyauddin S.,Dhake, Kishor P.,Khan, Shoeb R.,Bhanage, Bhalchandra M.
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supporting information; experimental part
p. 1490 - 1494
(2011/08/03)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Studies of the rates of thermal decomposition of glycine, alanine, and serine
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Rates of thermal decomposition of glycine, alanine, and serine are described by the equation of first order reaction in the temperature range 200-300°C. Apparent rate constants and apparent activation energies of decomposition of α-amino acids were evaluated. It was found that the main gaseos reaction product is carbon dioxide.
- Yablokov,Smel'tsova,Zelyaev,Mitrofanova
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body text
p. 1704 - 1706
(2011/05/14)
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- N1,N3-Diacyl-3,4-dihydropyrimidin-2(1H)-ones: neutral acyl group transfer reagents
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Readily available N1,N3-diacyl-3,4-dihydropyrimidin-2(1H)-ones efficiently acylate ammonia, primary and secondary amines to furnish primary, secondary and tertiary amides in good to excellent yields. The wide applicability of the procedure is demonstrated
- Singh, Kamaljit,Singh, Kawaljit
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experimental part
p. 10395 - 10399
(2010/02/28)
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