- Conversion of Aliphatic Amides into Amines with benzene. 2. Kinetics and Mechanism
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The reagent benzene (PIFA), used to prepare amines from amides as described in the preceding paper, dissolves in 50:50 (v/v) aqueous acetonitrile to give an acidic solution.This behavior can be explained quantitatively by the dimerization of PIFA in solution under preparatively significant conditions; the dimer, μ-oxo-I,I'-bis(trifluoroacetato-O)-I,I'-diphenyldiiodine(III), 2, can be isolated from the reaction mixture above pH 3.The rate of hexanamide rearrangement by PIFA was studied as a function of PIFA concentration and shown to display asymtotic behavior.The rate is depressed by added trifluoroacetate and accelerated by increasing pH, but not in a simple way.These observations can be accounted for by a mechanism (eq 13-15) in which the dimer 2 complexes with the amide, releasing acid.It is this released acid that accounts for most of the kinetically significant observations.The rearrangement of the amide-dimer complex is the rate-limiting step.Other kinetically indistinguishable mechanism are also possible.The rate of rearrangement promoted by dimer alone is in agreement with that predicted by the proposed mechanism.The imidic acid (enol) form of the amide is considered as a possible kinetically active form of the amide but is rejected on kinetic grounds.
- Boutin, Raymond H.,Loudon, G. Marc
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Read Online
- A New, One-Pot Synthesis of Primary 2-Alkynamides
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Chlorosulphonyl isocyanate (CSI) reacts with 1-trimethylsilyl acetylenes to give primary 2-alkynamides in good yields after hydrolytic work-up.
- Page, Philip C. Bulman,Rosenthal, Stephen,Williams, Richard Vaughan
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Read Online
- 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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- 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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- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
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Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
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supporting information
(2021/11/17)
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- One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
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The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
- Coeck, Robin,De Vos, Dirk E.
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supporting information
p. 5105 - 5114
(2020/08/25)
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- Arene-ruthenium(II)-phosphine complexes: Green catalysts for hydration of nitriles under mild conditions
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Three new arene-ruthenium(II) complexes were prepared by treating [{RuCl(μ-Cl)(η6-arene)}2] (η6-arene = p-cymene) dimer with tri(2-furyl)phosphine (PFu3) and 1,3,5-triaza-7-phosphaadamantane (PTA), respectively to obtain [RuCl2(η6-arene)PFu3] [Ru]-1, [RuCl(η6-arene)(PFu3)(PTA)]BF4 [Ru]-2 and [RuCl(η6-arene)(PFu3)2]BF4 [Ru]-3. All the complexes were structurally identified using analytical and spectroscopic methods including single-crystal X-ray studies. The effectiveness of resulting complexes as potential homogeneous catalysts for selective hydration of different nitriles into corresponding amides in aqueous medium and air atmosphere was explored. There was a remarkable difference in catalytic activity of the catalysts depending on the nature and number of phosphorus-donor ligands and sites available for catalysis. Experimental studies performed using structural analogues of efficient catalyst concluded a structural-activity relationship for the higher catalytic activity of [Ru]-1, being able to convert huge variety of aromatic, heteroaromatic and aliphatic nitriles. The use of eco-friendly water as a solvent, open atmosphere and avoidance of any organic solvent during the catalytic reactions prove the reported process to be truly green and sustainable.
- Vyas, Komal M.,Mandal, Poulami,Singh, Rinky,Mobin, Shaikh M.,Mukhopadhyay, Suman
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- Amine-boranes as Dual-Purpose Reagents for Direct Amidation of Carboxylic Acids
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Amine-boranes serve as dual-purpose reagents for direct amidation, activating aliphatic and aromatic carboxylic acids and, subsequently, delivering amines to provide the corresponding amides in up to 99% yields. Delivery of gaseous or low-boiling amines as their borane complexes provides a major advantage over existing methodologies. Utilizing amine-boranes containing borane incompatible functionalities allows for the preparation of functionalized amides. An intermolecular mechanism proceeding through a triacyloxyborane-amine complex is proposed.
- Choudhary, Shivani,Hamann, Henry J.,Ramachandran, P. Veeraraghavan
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supporting information
(2020/11/13)
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- Direct synthesis of amides from nonactivated carboxylic acids using urea as nitrogen source and Mg(NO3)2or imidazole as catalysts
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A new method for the direct synthesis of primary and secondary amides from carboxylic acids is described using Mg(NO3)2·6H2O or imidazole as a low-cost and readily available catalyst, and urea as a stable, and easy to manipulate nitrogen source. This methodology is particularly useful for the direct synthesis of primary and methyl amides avoiding the use of ammonia and methylamine gas which can be tedious to manipulate. Furthermore, the transformation does not require the employment of coupling or activating agents which are commonly required.
- Blacker, A. John,Chhatwal, A. Rosie,Lomax, Helen V.,Marcé, Patricia,Williams, Jonathan M. J.
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p. 5808 - 5818
(2020/06/21)
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- Selective Transformations of Triglycerides into Fatty Amines, Amides, and Nitriles by using Heterogeneous Catalysis
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The use of triglycerides as an important class of biomass is an effective strategy to realize a more sustainable society. Herein, three heterogeneous catalytic methods are reported for the selective one-pot transformation of triglycerides into value-added chemicals: i) the reductive amination of triglycerides into fatty amines with aqueous NH3 under H2 promoted by ZrO2-supported Pt clusters; ii) the amidation of triglycerides under gaseous NH3 catalyzed by high-silica H-beta (Hβ) zeolite at 180 °C; iii) the Hβ-promoted synthesis of nitriles from triglycerides and gaseous NH3 at 220 °C. These methods are widely applicable to the transformation of various triglycerides (C4–C18 skeletons) into the corresponding amines, amides, and nitriles.
- Jamil, Md. A. R.,Siddiki, S. M. A. Hakim,Touchy, Abeda Sultana,Rashed, Md. Nurnobi,Poly, Sharmin Sultana,Jing, Yuan,Ting, Kah Wei,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-ichi
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p. 3115 - 3125
(2019/04/26)
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- Aerobic Activation of C-H Bond in Amines Over a Nanorod Manganese Oxide Catalyst
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The development of heterogeneous catalysts for the synthesis of pharmaceutically relevant compounds is always important for chemistry research. Here, we report a selective aerobic oxidation of aromatic and aliphatic amines to corresponding amides over a nanorod manganese oxide (NR-MnOx) catalyst. The kinetic studies reveal that the NR-MnOx catalyzed amine-to-amide reaction proceeds the oxidative dehydrogenation of the amines into nitriles, followed by hydrolysis of nitrile into amides. The NR?MnOx exhibits fast kinetics and high selectivities in these steps, as well as hinders the by-product formation. More importantly, the NR-MnOx catalyst is stable and reusable in the continuous recycle tests with water as a sole by-product, exhibiting superior sustainability and significant advancement to outperform the traditional amide production route in acidic or basic media with toxic by-products.
- Wang, Hai,Wang, Liang,Wang, Sai,Dong, Xue,Zhang, Jian,Xiao, Feng-Shou
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p. 401 - 406
(2018/08/11)
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- Highly Selective Ruthenium-Catalyzed Direct Oxygenation of Amines to Amides
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Reports on aerobic oxidation of amines to amides are rare, and those reported suffer from several limitations like poor yield or selectivity and make use of pure oxygen under elevated pressure. Herein, we report a practical and an efficient ruthenium-catalyzed synthetic protocol that enables selective oxidation of a broad range of primary aliphatic, heterocyclic and benzylic amines to their corresponding amides, using readily available reagents and ambient air as the sole oxidant. Secondary amines instead, yield benzamides selectively as the sole product. Mechanistic investigations reveal intermediacy of nitriles, which undergo hydration to afford amide as the final product.
- Ray, Ritwika,Hazari, Arijit Singha,Chandra, Shubhadeep,Maiti, Debabrata,Lahiri, Goutam Kumar
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supporting information
p. 1067 - 1071
(2018/01/03)
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- Method for synthesizing primary amide compound
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The invention provides a method for synthesizing a primary amide compound. A nitrile compound and different N sources as raw materials and oxygen as an oxidizing agent undergo a reaction in the presence of a copper salt as a catalyst under mild conditions to produce the primary amide compound. The method utilizes a cheap and easily available copper salt as a catalyst, a commercial nitrile compound as a substrate and molecular O2 (oxygen) as an oxidant to realize nitrile oxidation and amidation reactions. The reaction conditions are mild, the raw materials are cheap and easily available, the adaptability of the reaction substrate is wide, the selectivity and yield of the product are high, the reaction conditions are mild, environmental friendliness is obtained, and the method has a good industrial application prospect.
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Paragraph 0070; 0071; 0072
(2017/08/28)
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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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- 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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- Phosphinous Acid-Assisted Hydration of Nitriles: Understanding the Controversial Reactivity of Osmium and Ruthenium Catalysts
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The synthesis and catalytic behavior of the osmium(II) complexes [OsCl2(η6-p-cymene)(PR2OH)] [R=Me (2 a), Ph (2 b), OMe (2 c), OPh (2 d)] in nitrile hydration reactions is presented. Among them, the best catalytic results were obtained with the phosphinous acid derivative [OsCl2(η6-p-cymene)(PMe2OH)] (2 a), which selectively provided the desired primary amides in excellent yields and short times at 80 °C, employing directly water as solvent, and without the assistance of any basic additive (TOF values up to 200 h?1). The process was successful with aromatic, heteroaromatic, aliphatic, and α,β-unsaturated organonitriles, and showed a high functional group tolerance. Indeed, complex 2 a represents the most active and versatile osmium-based catalyst for the hydration of nitriles reported so far in the literature. In addition, it exhibits a catalytic performance similar to that of its ruthenium analogue [RuCl2(η6-p-cymene)(PMe2OH)] (4). However, when compared to 4, the osmium complex 2 a turned out to be faster in the hydration of less-reactive aliphatic nitriles, whereas the opposite trend was generally observed with aromatic substrates. DFT calculations suggest that these differences in reactivity are mainly related to the ring strain associated with the key intermediate in the catalytic cycle, that is, a five-membered metallacyclic species generated by intramolecular addition of the hydroxyl group of the phosphinous acid ligand to the metal-coordinated nitrile.
- González-Fernández, Rebeca,Crochet, Pascale,Cadierno, Victorio,Menéndez, M. Isabel,López, Ramón
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p. 15210 - 15221
(2017/10/12)
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- A method of from [...] amide
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The invention discloses a method for synthesizing amides from oxime. The method is characterized by adding oxime, water and a water-soluble iridium complex catalyst to a reaction vessel, cooling a reactant to the room temperature after the reaction mixture reacts at 80-120 DEG C for several hours, removing water through selective evaporation, and obtaining a target product through column separation. Compared with existing methods for synthesizing amides through oxime rearrangement in water through transition metal catalysis, the method has the advantages that the used catalyst is low in load and does not contain phosphine ligands severely polluting the environment, so that the reaction can be carried out in the air, without nitrogen protection; therefore the reaction meets the green chemical requirements and has an extensive development prospect.
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Paragraph 0123-0127
(2017/01/31)
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- A method from the aldehyde amide
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The invention discloses a method for synthesizing amides from aldehyde. The method comprises the following steps: adding aldehyde, hydroxylamine hydrochloride, alkali and water to a reaction vessel to react at room temperature for half an hour; adding a water-soluble iridium complex after aldehyde is completely transformed into oxime, cooling a reactant to the room temperature after the reaction mixture reacts at 80-120 DEG C for several hours, removing water through selective evaporation, and obtaining a target product through column separation. Compared with existing methods for synthesizing amides by generating oxime through one-pot reaction between aldehyde and hydroxylamine in water and then carrying out rearrangement, the method has the advantages that the used catalyst is low in load and does not contain phosphine ligands severely polluting the environment, so that the reaction can be carried out in the air, without nitrogen protection; therefore the reaction meets the green chemical requirements and has an extensive development prospect.
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Paragraph 0055; 0056; 0057; 0058; 0059
(2017/04/08)
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- Ferric perchlorate-mediated one-step reaction of [60]fullerene with primary amides for the synthesis of fullerooxazoles
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The facile one-step reaction of [60]fullerene with primary amides promoted by cheap and easily available ferric perchlorate afforded a series of interesting fullerooxazole derivatives. The reaction was tolerant of a large variety of primary amides containing aryl, alkyl, and cinnamyl groups. A possible reaction mechanism for product formation was proposed.
- Zhang, Xiao-Feng,Li, Fa-Bao,Shi, Ji-Long,Wu, Jun,Liu, Li
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p. 1626 - 1632
(2016/02/19)
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- Method and apparatus for manufacturing carboxylic acid amide compound
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The present invention relates to a process and an apparatus for producing a carboxylic acid amide compound, and more particularly, to a process for producing a carboxylic acid amide compound which alternately performs a reaction process of a first manufacturing process that promotes the reaction between a first carboxylic acid and a first ammonia in the presence of a first catalyst and a reaction process of a second manufacturing process that promotes the reaction between a second carboxylic acid and a first ammonia in the presence of a second catalyst wherein each of them is progressed alternately between each preparation process so that the reaction between the carboxylic acid and the ammonia, which is intermittently carried out by the respective preparation processes, can be continuously performed, and moreover, the time required for the respective preparation processes is shortened, so that the carboxylic acid amide compound can be produced in a large amount in a short time.
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Paragraph 0059-0062; 0076
(2017/06/02)
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- Selective NaOH-catalysed hydration of aromatic nitriles to amides
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The selective synthesis of aromatic and heteroaromatic amides through base-catalysed hydration of nitriles was achieved using inexpensive and commercially available NaOH as the only catalyst. A wide range of nitriles was selectively converted to their corresponding amides. Kinetic studies show that the double hydration of nitriles towards undesirable carboxylic acids is negligible under our reaction conditions.
- Schmid, Thibault E.,Gómez-Herrera, Alberto,Songis, Olivier,Sneddon, Deborah,Révolte, Antoine,Nahra, Fady,Cazin, Catherine S. J.
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p. 2865 - 2868
(2015/05/27)
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- Palladium(II) complexes with a phosphino-oxime ligand: Synthesis, structure and applications to the catalytic rearrangement and dehydration of aldoximes
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The treatment of [PdCl2(COD)] (COD = 1,5-cyclooctadiene) with 1 and 2 equivalents of 2-(diphenylphosphino)benzaldehyde oxime in dichloromethane at room temperature led to the selective formation of [PdCl2{κ2-(P,N)-2-Ph2PC6H4CHNOH}] (1) and [Pd{κ2-(P,N)-2-Ph2PC6H4CHNOH}2][Cl]2 (2), respectively, which represent the first examples of Pd(II) complexes containing a phosphino-oxime ligand. These compounds, whose structures were fully confirmed by X-ray diffraction methods, were active in the catalytic rearrangement of aldoximes. In particular, using 5 mol% complex 1, a large variety of aldoximes could be cleanly converted into the corresponding primary amides at 100 °C, employing water as solvent and without the assistance of any cocatalyst. Palladium nanoparticles are the active species in the rearrangement process. In addition, when the same reactions were performed employing acetonitrile as solvent, selective dehydration of the aldoximes to form the respective nitriles was observed. For comparative purposes, the catalytic behaviour of an oxime-derived palladacyclic complex has also been briefly evaluated.
- Menéndez-Rodríguez, Lucía,Tomás-Mendivil, Eder,Francos, Javier,Nájera, Carmen,Crochet, Pascale,Cadierno, Victorio
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p. 3754 - 3761
(2015/07/01)
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- Rearrangement of aldoximes to amides in water under air atmosphere catalyzed by water-soluble iridium complex [Cp*Ir(H2O) 3][OTf]2
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In the presence of the water-soluble iridium complex [Cp*Ir(H 2O)3][OTf]2, a variety of aldoximes, including aromatic, aliphatic, conjugated unsaturated and non-conjugated unsaturated, were converted into their corresponding amides in water with good to excellent yields. Further, the one-pot synthesis of amides from aldehydes, hydroxylamine hydrochloride and sodium carbonate via a tandem condensation-rearrangement reaction in water was also accomplished. Compared with the reported organometallic catalysts for the rearrangement of aldoximes to amides in water, the present catalyst exhibited some advantages such as being phosphorus ligand-free, having low catalyst loading, and operational convenience under air atmosphere. This journal is the Partner Organisations 2014.
- Sun, Chunlou,Qu, Panpan,Li, Feng
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p. 988 - 996
(2014/04/03)
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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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- Thiazolyl-phosphine hydrochloride salts: Effective auxiliary ligands for ruthenium-catalyzed nitrile hydration reactions and related amide bond forming processes in water
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A series of water-soluble N-protonated thiazolyl-phosphine hydrochloride salts have been synthesized and coordinated to the ruthenium(ii) fragment [RuCl2(η6-p-cymene)]. The resulting complexes were evaluated as potential catalysts for the selective hydration of nitriles to primary amides in environmentally friendly aqueous medium. The best results in terms of activity were achieved when tris(5-(2-aminothiazolyl))phosphine trihydrochloride was used as ligand. Using the Ru(ii) complex 9 derived from this salt (3 mol%), the catalytic reactions proceeded cleanly in pure water at 100 °C without the assistance of any additive, affording the desired amides in high yields (>78%) after short reaction periods (0.5-7 h). The process was operative with both aromatic, heteroaromatic, α,β-unsaturated and aliphatic nitriles, and tolerated several functional groups. The utility of 9 in promoting the formation of primary amides in water by catalytic rearrangement of aldoximes and direct coupling of aldehydes with NH2OH·HCl has also been demonstrated.
- Garcia-Alvarez, Rocio,Zablocka, Maria,Crochet, Pascale,Duhayon, Carine,Majoral, Jean-Pierre,Cadierno, Victorio
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p. 2447 - 2456
(2013/09/12)
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- I2-TEMPO as an efficient oxidizing agent for the one-pot conversion of alcohol to amide using FeCl3 as the catalyst
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A high yield one-pot method for the synthesis of amides from alcohols is described. The aldehyde was generated in situ using iodine-TEMPO as oxidizing agent followed by intermediate oxime formation through reaction with NH 2OH?HCl and finally rearrangement of oxime catalyzed by FeCl3.
- Das, Rima,Chakraborty, Debashis
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experimental part
p. 48 - 53
(2012/08/28)
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- Hydration of nitriles to amides in water by SiO2-supported Ag catalysts promoted by adsorbed oxygen atoms
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A series of silica-supported silver catalysts with similar Ag loading (5 or 7 wt%) but with different preparation methods (calcination in air and reduction by H2 or NaBH4) were prepared, and their structure was characterized by microscopy (STEM), X-ray absorption fine structure (XAFS), and CO-titration of surface oxygen atom. Ag is present as metal nanoparticle with a size range of 17-30 nm. Their surface was partially covered with oxygen atoms, and the surface coverage of the oxygen depends on the preparation condition. For hydration of 2-cyanopyridine as a test reaction, turnover frequency (TOF) per surface Ag species is estimated. TOF does not show a good correlation with Ag particle size, but it linearly increases with the coverage of the surface oxygen atoms on Ag particles. The Ag/SiO2 catalyst prepared by H 2 reduction at 700 °C shows the highest TOF and it acts as effective and recyclable heterogeneous catalyst for selective hydration of various nitriles to the corresponding amides. Kinetic and Raman spectroscopic studies suggest that the surface oxygen atom adjacent to Ag0 sites plays an important role in the dissociation of H2O.
- Shimizu, Ken-Ichi,Imaiida, Naomichi,Sawabe, Kyoichi,Satsuma, Atsushi
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experimental part
p. 114 - 120
(2012/06/04)
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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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- Lead discovery, chemistry optimization, and biological evaluation studies of novel biamide derivatives as CB2 receptor inverse agonists and osteoclast inhibitors
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N,N′-((4-(Dimethylamino)phenyl)methylene)bis(2-phenylacetamide) was discovered by using 3D pharmacophore database searches and was biologically confirmed as a new class of CB2 inverse agonists. Subsequently, 52 derivatives were designed and synthesized through lead chemistry optimization by modifying the rings A-C and the core structure in further SAR studies. Five compounds were developed and also confirmed as CB2 inverse agonists with the highest CB2 binding affinity (CB2Ki of 22-85 nM, EC50 of 4-28 nM) and best selectivity (CB 1/CB2 of 235- to 909-fold). Furthermore, osteoclastogenesis bioassay indicated that PAM compounds showed great inhibition of osteoclast formation. Especially, compound 26 showed 72% inhibition activity even at the low concentration of 0.1 μM. The cytotoxicity assay suggested that the inhibition of PAM compounds on osteoclastogenesis did not result from its cytotoxicity. Therefore, these PAM derivatives could be used as potential leads for the development of a new type of antiosteoporosis agent.
- Yang, Peng,Myint, Kyaw-Zeyar,Tong, Qin,Feng, Rentian,Cao, Haiping,Almehizia, Abdulrahman A.,Alqarni, Mohammed Hamed,Wang, Lirong,Bartlow, Patrick,Gao, Yingdai,Gertsch, Jürg,Teramachi, Jumpei,Kurihara, Noriyoshi,Roodman, Garson David,Cheng, Tao,Xie, Xiang-Qun
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p. 9973 - 9987
(2013/01/16)
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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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- Efficient synthesis of primary amides from carboxylic acids using n,n'-carbonyldiimidazole and ammonium acetate in ionic liquid
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A novel and efficient method for the conversion of carboxylic acids to primary amides using N,N'-carbonyldiimidazole in combination with ammonium acetate/triethyl amine system in [BMIM]BF4 is developed.
- Lee, Kwan Soo,Kim, Kee D.
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experimental part
p. 3497 - 3500
(2011/09/30)
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- Arene-ruthenium(II) complexes containing inexpensive tris(dimethylamino) phosphine: Highly efficient catalysts for the selective hydration of nitriles into amides
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The catalytic hydration of nitriles into amides, in water under neutral conditions, has been studied using a series of arene-ruthenium(II) derivatives containing the commercially available and inexpensive ligand tris(dimethylamino)phosphine. Among them, best results were obtained with the complex [RuCl2(η6-C6Me6) {P(NMe2)3}], which selectively provided the desired amides in excellent yields and short times (TOF values up to 11 400 h-1). The process was operative with both aromatic, heteroaromatic, aliphatic, and α,β-unsaturated organonitriles and showed a high functional group tolerance. The stability of [RuCl2(η6-C 6Me6){P(NMe2)3}] in water was evaluated, observing its progressive decomposition into the less-active dimethylamine-ruthenium(II) complex [RuCl2(η6-C 6Me6)(NHMe2)] by hydrolysis of the coordinated P(NMe2)3 ligand. The X-ray crystal structure determination of the toluene complex [RuCl2(η6-C6H 5Me){P(NMe2)3}] is also included.
- Garcia-Alvarez, Rocio,Diez, Josefina,Crochet, Pascale,Cadierno, Victorio
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experimental part
p. 5442 - 5451
(2011/12/13)
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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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- Probing the enantioselectivity of a diverse group of purified cobalt-centred nitrile hydratases
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In this study a diverse range of purified cobalt containing nitrile hydratases (NHases, EC 4.2.1.84) from Rhodopseudomonas palustris HaA2 (HaA2), Rhodopseudomonas palustris CGA009 (009), Sinorhizobium meliloti 1021 (1021), and Nitriliruptor alkaliphilus (iso2), were screened for the first time for their enantioselectivity towards a broad range of chiral nitriles. Enantiomeric ratios of >100 were found for the NHases from HaA2 and CGA009 on 2-phenylpropionitrile. In contrast, the Fe-containing NHase from the well-characterized Rhodococcus erythropolis AJ270 (AJ270) was practically aselective with a range of different α-phenylacetonitriles. In general, at least one bulky group in close proximity to the α-position of the chiral nitriles seemed to be necessary for enantioselectivity with all NHases tested. Nitrile groups attached to a quaternary carbon atom were only reluctantly accepted and showed no selectivity. Enantiomeric ratios of 80 and >100 for AJ270 and iso2, respectively, were found for the pharmaceutical intermediate naproxennitrile, and 3-(1-cyanoethyl)benzoic acid was hydrated to the corresponding amide by iso2 with an enantiomeric ratio of >100.
- Van Pelt,Zhang,Otten,Holt,Sorokin,Van Rantwijk,Black,Perry,Sheldon
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experimental part
p. 3011 - 3019
(2011/06/17)
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- Metal-free one-pot oxidative conversion of benzylic alcohols and benzylic halides into aromatic amides with molecular iodine in aq ammonia, and hydrogen peroxide
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Various primary alcohols, particularly benzylic alcohols, could be converted into the corresponding aromatic amides in good yields in a one-pot manner by treatment with molecular iodine in aq. NH3, followed by reaction with ～30% aq H2O2. Similarly, various benzylic halides could be also converted into the corresponding aromatic amides in good yields in a one-pot manner by treatment with molecular iodine in aq NH3, followed by reaction with ～30% aq H2O 2. The present reactions involve the metal-free one-pot oxidative conversion of benzylic alcohols and benzylic halides into the corresponding aromatic amides, respectively.
- Ohmura, Ryosuke,Takahata, Misato,Togo, Hideo
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experimental part
p. 4378 - 4381
(2010/09/12)
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- Arene-ruthenium(II) complexes containing amino-phosphine ligands as catalysts for nitrile hydration reactions
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Three different series of novel mononuclear arene-ruthenium(II) complexes containing amino-phosphine ligands, namely, [RuCl2{κ 1(P)-2-Ph2PC6H4CH 2NHR}(η6-arene)], [RuCl2{κ 1(P)-3-Ph2PC6H4CH 2NHR}(η6-arene)], and [RuCl2{κ 1(P)-4-Ph2PC6H4CH 2NHR}(η6-arene)] (arene = C6H6, p-cymene, 1,3,5-C6H3Me3, C6Me 6; R = iPr, tBu; all combinations), have been synthesized and fully characterized. These readily accessible species are efficient catalysts for the selective hydration of organonitriles into amides under challenging reaction conditions, i.e., pure aqueous medium in the absence of any cocatalyst, being much more active than their corresponding nonfunctionalized triphenylphosphine counterparts [RuCl2(PPh 3)(η6-arene)]. The results obtained in this study indicate that the (amino-phosphine)ruthenium(II) complexes operate through a "bifunctional catalysis" mechanism in which the ruthenium center acts as a Lewis acid, activating the nitrile molecule, and the P-donor ligand acts as a Brnsted base, the pendant amino group generating the real nucleophile of the hydration process, i.e., the OH- group.
- Garcia-Alvarez, Rocio,Diez, Josefina,Crochet, Pascale,Cadierno, Victorio
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experimental part
p. 3955 - 3965
(2010/12/25)
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- Palladium-catalyzed one-pot conversion of aldehydes to amides
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The palladium-catalyzed one-pot conversion of aldehydes into primary amides in the presence of hydroxylamine hydrochloride in aqueous dimethyl sulfoxide (DMSO) at moderate temperature is described. The process is selective and free from the addition of an external chelating ligand.
- Ali, Md. Ashif,Punniyamurthy, Tharmalingam
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experimental part
p. 288 - 292
(2010/04/28)
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- Supported silver nanoparticle catalyst for selective hydration of nitriles to amides in water
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Hydroxyapatite-supported silver nanoparticles (AgHAP) acted as a highly efficient reusable heterogeneous catalyst for hydration of diverse nitriles, including heteroaromatic ones, into amides in water.
- Mitsudome, Takato,Mikami, Yusuke,Mori, Haruhiko,Arita, Shusuke,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information; scheme or table
p. 3258 - 3260
(2009/12/01)
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- Discovery and biological evaluation of novel cyanoguanidine P2X7 antagonists with analgesic activity in a rat model of neuropathic pain
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We disclose the design of a novel series of cyanoguanidines that are potent (IC50 ? 10-100 nM) and selective (≥100-fold) P2X7 receptor antagonists against the other P2 receptor subtypes such as the P2Y2, P2X4, and P2X3. We also found that these P2X7 antagonists effectively reduced nociception in a rat model of neuropathic pain (Chung model). Particularly, analogue 53 proved to be effective in the Chung model, with an ED50 of 38 μmol/kg after intraperitoneal administration. In addition compound 53 exhibited antiallodynic effects following oral administration and maintained its efficacy following repeated administration in the Chung model. These results suggest an important role of P2X7 receptors in neuropathic pain and therefore a potential use of P2X7 antagonists as novel therapeutic tools for the treatment of this type of pain.
- Perez-Medrano, Arturo,Donnelly-Roberts, Diana L.,Honore, Prisca,Hsieh, Gin C.,Namovic, Marian T.,Peddi, Sridhar,Shuai, Qi,Wang, Ying,Faltynek, Connie R.,Jarvis, Michael F.,Carroll, William A.
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scheme or table
p. 3366 - 3376
(2010/04/03)
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- Heterogeneously catalyzed efficient oxygenation of primary amines to amides by a supported ruthenium hydroxide catalyst
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(Chemical Equation Presented) Supporting green chemistry: The supported ruthenium hydroxide Ru(OH)x/Al2O3 acts as an efficient heterogeneous catalyst for the oxygenation of primary amines to primary amides (see scheme). Various primary amines (including aromatic, aliphatic, and heterocyclic) are converted in aqueous media, using air as the sole oxidant and producing only water as a by-product.
- Kim, Jung Won,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information; experimental part
p. 9249 - 9251
(2009/05/15)
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- RhI-catalyzed hydration of organonitriles under ambient conditions
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(Chemical Presented) New scoop on scope and selectivity: The hydration of organonitriles catalyzed by a RhI(OMe) species under nearly pH-neutral and ambient conditions (25°C, 1 atm) is chemoselective and high-yielding (93 to 99%), has a broad substrate scope, and may thus be complementary to enzymatic hydration methods for the introduction of a terminal amido group (CONH2) onto a carbon chain.
- Goto, Akihiro,Endo, Kohei,Saito, Susumu
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p. 3607 - 3609
(2008/12/23)
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- Selective ruthenium-catalyzed hydration of nitriles to amides in pure aqueous medium under neutral conditions
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A study was conducted to demonstrate that water-soluble ruthenium(II) complexes can be used as catalysts for the hydration of nitriles in pure aqueous media and under neutral conditions. The hydration of benzonitrile was investigated as a model reaction and the ruthenium precursor was added to a 0.33M aqueous solution of benzonitrile at 100°C, while the reaction was monitored by gas chromatography. All the complexes checked, were found to be active and selective catalysts in the hydration process, providing benzamide as a specific reaction product. The most relevant results were obtained by using ruthenium complexes, bearing a nitrogen-containing ligand, which led to appropriate production of benzamide. The most effective ruthenium complex was found to be an efficient catalyst for the selective hydration of a large number of other nitriles.
- Cadierno, Victorio,Francos, Javier,Gimeno, Jose
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scheme or table
p. 6601 - 6605
(2009/07/10)
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- Selective synthesis of primary amines directly from alcohols and ammonia
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(Chemical Equation Presented) Air stable and waterproof: Selective and efficient synthesis of primary amines directly from alcohols and ammonia is achieved under mild conditions (see scheme). The reaction is homogenously catalyzed by a novel air-stable ruthenium pincer complex and can proceed in toluene or even in the absence of solvent or "on water".
- Gunanathan, Chidambaram,Milstein, David
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supporting information; experimental part
p. 8661 - 8664
(2009/05/15)
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- Efficient tandem process for the catalytic deprotection of N-allyl amides and lactams in aqueous media: A novel application of the bis(allyl)- ruthenium(IV) catalysts [Ru(η3:η2: η3-C12H18)Cl2] and [Ru(η3:η3-C10H16)-(μ-Cl) Cl}2]
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An operationally simple and highly efficient methodology for the removal of the allyl protecting group in amides and lactams has been developed by using the commercially available bis(allyl)-ruthenium(IV) catalysts [Ru(η3:η2:η3-C12H 18)Cl2] (C12H18 = dodeca-2,6,10-triene-1,12-diyl) and [(Ru(η3:η3- C10H16)(μ-Cl)Cl}2] (C10H 16 = 2,7-dimethylocta-2,6-diene-1,8-diyl). The tandem process, which takes place in aqueous media and proceeds in a one-pot manner, involves the initial isomerization of the C=C bond of the allyl unit and subsequent oxidative cleavage of the resulting enamide.
- Cadierno, Victorio,Gimeno, Jose,Nebra, Noel
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p. 6590 - 6594
(2008/03/13)
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- Silica-supported 2,4,6-trichloro-1,3,5-triazine as an efficient reagent for direct conversion of carboxylic acids to amides under solvent-free conditions
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A very simple and efficient solvent-free method for the direct conversion of carboxylic acids to primary, secondary, tertiary alkyl, and aromatic amides in the presence of the corresponding ammonium salts, silica-supported 2,4,6-trichloro-1,3,5-triazine, and triethylamine is described. The reactions proceed rapidly at room temperature, and the products are obtained in moderate to excellent yields. Copyright Taylor & Francis Group, LLC.
- Khalafi-Nezhad, Ali,Zare, Abdolkarim,Parhami, Abolfath,Rad, Mohammad Navid Soltani,Nejabat, Gholam Reza
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p. 657 - 666
(2008/09/21)
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- Enzymatic nitrile hydrolysis catalyzed by nitrilase ZmNIT2 from maize. An unprecedented β-hydroxy functionality enhanced amide formation
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To explore the synthetic potential of nitrilase ZmNIT2 from maize, the substrate specificity of this nitrilase was studied with a diverse collection of nitriles. The nitrilase ZmNIT2 showed high activity for all the tested nitriles except benzonitrile, producing both acids and amides. For the hydrolysis of aliphatic, aromatic nitriles, phenylacetonitrile derivatives and dinitriles, carboxylic acids were the major products. Unexpectedly, amides were found to be the major products in nitrilase ZmNIT2-catalyzed hydrolysis of β-hydroxy nitriles. The hydrogen bonding between the hydroxyl group and nitrogen in the enzyme-substrate complex intermediates that disfavors the loss of ammonia and formation of acyl-enzyme intermediate, which was further hydrolyzed to acid, was proposed to be responsible for the unprecedented β-hydroxy functionality assisted high yield of amide formation.
- Mukherjee, Chandrani,Zhu, Dunming,Biehl, Edward R.,Parmar, Rajiv R.,Hua, Ling
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p. 6150 - 6154
(2007/10/03)
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- Efficient method for the direct preparation of amides from carboxylic acids using tosyl chloride under solvent-free conditions
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A simple, clean and highly efficient solvent-free procedure for the preparation of primary, secondary, tertiary and aromatic amides is described from the direct reaction of carboxylic acids and silica-supported ammonium salts, triethylamine (TEA) and tosyl chloride (TsCl) as condensing agent. The reaction proceeds rapidly in high yields at room temperature.
- Khalafi-Nezhad, Ali,Parhami, Abolfath,Soltani Rad, Mohammad Navid,Zarea, Abdolkarim
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p. 6879 - 6882
(2007/10/03)
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- Efficient hydration of nitriles to amides in water, catalyzed by ruthenium hydroxide supported on alumina
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A broad range of amides is accessible in excellent yield (> 99%) by hydration of the corresponding nitriles in water in the presence of the supported ruthenium catalyst Ru(OH)x/Al2O3 (see scheme). For example, the industrially important conversion of acrylonitrile into acrylamide was achieved in quantitative yield and better than 99% selectivity. The catalyst can be reused without loss of catalytic activity and selectivity.
- Yamaguchi, Kazuya,Matsushita, Mitsunori,Mizuno, Noritaka
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p. 1576 - 1580
(2007/10/03)
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- LTB4 antagonists and radiopharmaceuticals for imaging infection and inflammation
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The present invention provides novel radiopharmaceutials useful for the diagnosis of infection and inflammation, reagents and kits useful for preparing the radiopharmaceuticals, methods of imaging sites of infection and/or inflammation in a patient, and methods of diagnosing diseases associated with infection or inflammation in patients in need of such diagnosis. The radiopharmaceuticals bind in vivo to the leukotriene B4 (LTB4) receptor on the surface of leukocytes which accumulate at the site of infection and inflammation. The reagents provided by this invention are also useful for the treatment of diseases associated with infection and inflammation.
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- Direct preparation of primary amides from carboxylic acids and urea using imidazole under microwave irradiation
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A very simple and efficient solvent-free procedure for the preparation of primary amides is described from carboxylic acids and urea using imidazole under microwave irradiation. Various aliphatic and aromatic primary amides were prepared in good yields by this direct amidation method.
- Khalafi-Nezhad, Ali,Mokhtari, Babak,Rad, Mohammad Navid Soltani
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p. 7325 - 7328
(2007/10/03)
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- Catalysis of a hydroxyapatite-bound Ru complex: Efficient heterogeneous oxidation of primary amines to nitriles in the presence of molecular oxygen
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A hydroxyapatite-bound Ru complex could efficiently catalyze the aerobic oxidation of various primary amines to nitriles which were further hydrated to amides in the presence of water.
- Mori,Yamaguchi,Mizugaki,Ebitani,Kaneda
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p. 461 - 462
(2007/10/03)
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- Oxidative cleavage of the C=N bond during singlet oxygenations of amidoximates
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Amidoximes are inert toward singlet oxygen (1O2), however, the photooxygenation of amidoximate anions proceeds smoothly and in high yield to give mixtures of amides and nitriles. The mechanism of these reactions appears to involve carbonyl oxide intermediates. The oxidative cleavage of amidoximates closely resembles the results obtained from nitric oxide synthase (NOS) oxidations of N-hydroxyarginine.
- ?cal, Nüket,Erden, Ihsan
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p. 4765 - 4767
(2007/10/03)
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