- Oxidative Coupling between Methylarenes and Ammonia: A Direct Approach to Aromatic Primary Amides
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A direct oxidative amidation between methylarenes and aqueous ammonia using a tert-butyl hydroperoxide and tetrabutylammonium iodide (TBHP/TBAI) oxidation system with co-catalysis of iron(III) chloride has been developed. Both coupling partners were used in their native form to render prior functionalization unnecessary and afford a facile approach to aromatic primary amides.
- Zhao, Zhenguang,Wang, Tao,Yuan, Lin,Hu, Xu,Xiong, Fei,Zhao, Junfeng
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- Coupling of CH 3 OH and CO 2 with 2-cyanopyridine for enhanced yields of dimethyl carbonate over ZnO – CeO 2 catalyst
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Abstract: The present work is aimed to produce dimethyl carbonate by coupling of CH 3OH and CO 2 with 2-cyanopyridine over ZnO–CeO 2 catalysts prepared by co-precipitation method. These catalysts were characterized by XRD, TEM, UV-Vis DRS, BET surface area, CO 2 and NH 3-TPD techniques and applied for the titled reaction. Among the investigated catalysts 10ZnO–90CeO 2 catalyst with CeO 2 crystallite size 8.0?nm exhibited 96% conversion of methanol with 99% selectivity to dimethyl carbonate. The superior catalytic activity is a unified effect of crystalline size of CeO 2 and presence of an optimum number of acidic and basic sites. This protocol offers enhanced conversion of methanol with the simultaneous conversion of 2-cyanopyridine into 2-picolinamide by removing water molecules formed in the reaction. Graphic Abstract: Incorporation of ZnO with CeO 2 enhanced the number of active sites, i.e., acidic and basic sites due to synergetic effect between ZnO and CeO 2. The role of 2-cyano pyridine is to act as a dehydrating agent for the removal of H 2O. [Figure not available: see fulltext.]
- Challa, Prathap,Venkata Rao,Nagaiah,Nagu,David Raju,Rama Rao
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- Copper-Mediated Reactions of Nitriles with Nitromethanes: Aza-Henry Reactions and Nitrile Hydrations
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In this study, the first aza-Henry reaction of nitriles with nitromethane in a CuI/Cs2CO3/DBU system is described. The process was conveniently and directly used for the synthesis of β-aminonitroalkenes 2a-x and tolerated aryl-, alkyl-, hetaryl-, alkenyl-, and alkynylnitriles. The resulting aminonitroalkenes 2 could be successfully transformed to the corresponding 2-nitroacetophenones, 2-amino-1-halonitroalkenes, 2-alkylaminonitroalkenes, or 3-nitropyridines. In the presence of H2O, the aza-Henry reaction turned the reaction path to the nitrile hydration to exclusively yield the amides 3a-s.
- Kuwabara, Jun,Sawada, Yoshiharu,Yoshimatsu, Mitsuhiro
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- Aqueous-Phase Nitrile Hydration Catalyzed by an In Situ Generated Air-Stable Ruthenium Catalyst
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RuCl2(PTA)4 (PTA=1,3,5-triaza-7-phosphaadamantane) is an active, recyclable, air-stable, aqueous-phase nitrile hydration catalyst. The development of an in situ generated aqueous-phase nitrile hydration catalyst (RuCl3?3 H2O+6 equivalents PTA) is reported. The activity of the in situ catalyst is comparable to RuCl2(PTA)4. The effects of [PTA] on the activity of the reaction were investigated: the catalytic activity, in general, increases as the pH goes up, which shows a positive correlation with [PTA]. The pH effects were further explored for both the in situ and RuCl2(PTA)4 catalyzed reaction in phosphate buffer solutions with particular attention given to pH 6.8 buffer. Increased catalytic activity was observed at pH 6.8 versus water for both systems with turnover frequency (TOF) up to 135 h?1 observed for RuCl2(PTA)4 and 64 h?1 for the in situ catalyst. Catalyst loading down to 0.001 mol % was examined with turnover numbers as high as 22 000 reported. Similar to the preformed catalyst, RuCl2(PTA)4, the in situ catalyst could be recycled more than five times without significant loss of activity from either water or pH 6.8 buffer.
- Ounkham, Whalmany L.,Weeden, Jason A.,Frost, Brian J.
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- Substrate access tunnel engineering for improving the catalytic activity of a thermophilic nitrile hydratase toward pyridine and pyrazine nitriles
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Nitrile hydratase (NHase) is able to bio-transform nitriles into amides. As nitrile hydration being an exothermic reaction, a NHase with high activity and stability is needed for amide production. However, the widespread use of NHase for amide bio-production is limited by an activity-stability trade-off. In this study, through the combination of substrate access tunnel calculation, residue conservative analysis and site-saturation mutagenesis, a residue located at the substrate access tunnel entrance of the thermophilic NHase from extremophile Caldalkalibacillus thermarum TA2. A1, βLeu48, was semi-rationally identified as a potential gating residue that directs the enzymatic activity toward various pyridine and pyrazine nitriles. The specific activity of the corresponding mutant βL48H towards 3-cyanopyridine, 2-cyanopyridine and cyanopyrazine were 2.4-fold, 2.8-fold and 3.1-fold higher than that of its parent enzyme, showing a great potential in the industrial production of high-value pyridine and pyrazine carboxamides. Further structural analysis demonstrated that the βHis48 could form a long-lasting hydrogen bond with αGlu166, which contributes to the expansion of the entrance of substrate access tunnel and accelerate substrate migration.
- Cheng, Zhongyi,Jiang, Shijin,Zhou, Zhemin
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- Aminocarbonylation of Aryl Halides to Produce Primary Amides by Using NH4HCO3 Dually as Ammonia Surrogate and Base
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An efficient and clean protocol was developed for rapid production of primary aromatic amides by aminocarbonylation with NH4HCO3. Without addition of auxiliary base, the use of solid and cheap NH4HCO3 dually as ammonia surrogate and base not only promoted aminocarbonylation over subsequent dehydration and hydrolysis of amides owing to its weak basicity, and it also made the reaction manipulation clean and simplified without the presence of stinky NH3 or organic amines. The Xantphos ligand with relatively intensive π-acceptor character (1J31P–77Se=758 Hz) and wide natural bite angle (βn=111°) was found to be indispensable for the high efficiency of this reaction.
- Wang, Dong-Liang,Liu, Huan,Yang, Da,Wang, Peng,Lu, Yong,Liu, Ye
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- Direct synthesis of dimethyl carbonate from CO2 and methanol over CeO2 catalysts of different morphologies
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The direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol is an attractive approach towards conversion of the greenhouse gas - CO2 into value-added chemicals and fuels. Ceria (CeO2) catalyzes this reaction. But the conversion efficiency of CeO2 is enhanced when the byproduct water in the reaction medium is separated by employing trapping agents like 2-cyanopyridine (2-CP). In this work, the influence of morphology of CeO2 on the direct synthesis of DMC in presence of 2-CP is reported. CeO2 catalysts of cube, rod, spindle and irregular morphology (Ce - C, Ce - R, Ce - S and Ce - N, respectively) were prepared, characterized and studied as catalysts in the said reaction conducted in a batch mode. Among all, Ce - S shows superior catalytic performance with nearly 100 mol% of DMC selectivity. Catalytic activity correlates with the concentration of acid and base sites of medium strength as well as defect sites. Ce - S has an optimum number of these active sites and thereby shows superior catalytic performance. [Figure not available: see fulltext.]
- Unnikrishnan,Darbha, Srinivas
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- Efficient and substrate-specific hydration of nitriles to amides in water by using a CeO2 catalyst
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CeO2 acted as a reusable and effective catalyst for the hydration of various nitriles to amides in water under neutral conditions at low temperature (30-100 °C). CeO2 showed notable substrate specificity for nitriles that have a heteroatom adjacent to the α-carbon atom of the CN group (see scheme).
- Tamura, Masazumi,Wakasugi, Hiroko,Shimizu, Ken-Ichi,Satsuma, Atsushi
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- Ruthenium(III) 2-(aminofluoreneazo)phenolate complexes: Synthesis, characterization, catalytic activity in amidation reaction and Fluorescence quenching studies
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A series of ruthenium(III)2-(aminofluoreneazo)phenolate complexes with general formula [RuCl(PPh3)2(L1-5)] (1–5) (L = 2-(aminofluoreneazo)phenolate ligands) have been synthesized. The characterization of the synthesized complexes was accomplished by elemental analysis, spectroscopic (FT-IR, UV–Vis, Fluorescence and EPR) and ESI-MStechniques. The catalytic performance of one of the synthesized complexes 3 for the amidation of aldehyde in the presence of NaHCO3/NH2OH·HCl has been evaluated. The fluorescence emission of complexes [RuCl(PPh3)2(L2)] (2) and [RuCl(PPh3)2(L3) (3)] are effectively quenched by 1,4-benzoquinone and 1,4-naphthoquinone in acetonitrile medium.
- Thirumal, Muniyappan,Venkatachalam, Galmari,Venkattappan, Anbazhagan
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- Metal-free one-pot domino reaction: Chemoselective synthesis of polyarylated oxazoles
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A convenient method has been established for the chemoselective synthesis of polyarylated oxazoles from aromatic aldehydes and 2-cyano heteroarenes. The protocol presents a novel one-pot methodology for the synthesis of oxazole derivatives without any metal catalysts or extra oxidants. Photophysical test showed that the polyarylated oxazoles may serve as potential fluorescent materials with blue light-emitting properties.
- Meng, Hua,Zi, You,Xu, Xiao-Ping,Ji, Shun-Jun
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- Enhancements of dimethyl carbonate synthesis from methanol and carbon dioxide: The in situ hydrolysis of 2-cyanopyridine and crystal face effect of ceria
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This paper describes the effect of the in situ hydrolysis of 2-cyanopyridine and its derivatives on the synthesis of dimethyl carbonate (DMC) from CO2 and methanol over CeO2. 2-Cyanopyridine, with the highest electronic charge number of the carbon in the cyanogroup, is the most effective agent to accelerate the desired reaction by a decrease of water. CeO2 (1 1 0) planes are active for the hydrolysis of 2-cyanopyridine, further enhancing the DMC formation by in situ removal of water effectively. The DMC yield is improved drastically up to 378.5 mmol g cat-1 from 12.8 mmol g cat-1 with the in situ hydrolysis of 2-cyanopyridine over rod-CeO2 (1 1 0) catalyst.
- Wang, Sheng-Ping,Zhou, Jing-Jie,Zhao, Shu-Yang,Zhao, Yu-Jun,Ma, Xin-Bin
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- Synthesis of novel racemic 3,4-dihydroferroceno[c]pyridines via the Ritter reaction
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A new approach for the synthesis of functionalized racemic 3,4-dihydroferroceno[c]pyridines via the Ritter reaction of 2-methyl-1-ferrocenylpropan-1-ol with nitriles in the presence of methansulfonic acid was developed. The scope and limitations of the reaction were evaluated. Selected racemic 3,4-dihydroferroceno[c]pyridines were successfully separated by preparative HPLC on a Chiralcel OD-H column. The absolute configuration of the enantiomers was determined by X-ray crystal structure analysis.
- Rozhkova, Yuliya S.,Plekhanova, Irina V.,Gorbunov, Alexey A.,Stryapunina, Olga G.,Chulakov, Evgeny N.,Krasnov, Victor P.,Ezhikova, Marina A.,Kodess, Mikhail I.,Slepukhin, Pavel A.,Shklyaev, Yurii V.
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- Half-sandwich ruthenium(II) complexes containing biphenylamine based Schiff base ligands: Synthesis, structure and catalytic activity in amidation of various aldehydes
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New half-sandwich ruthenium (II) complexes [η6?p-cymene)Ru (L1-3)Cl] (1–3) containing biphenylamine based Schiff base ligands (HL1-3) have been synthesized and characterized by analytical and spectroscopic methods. Additionally, the solid state structure of 2 has been determined by single crystal X-ray diffraction study. The complex 2 serves as a catalyst for the amidation of various aldehydes to amides in good yield.
- Nagalakshmi, Veerasamy,Nandhini, Raja,Brindha, Veerappan,Krishnamoorthy, Bellie Sundaram,Balasubramani, Kasthuri
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- Efficient hydration of nitriles promoted by simple amorphous manganese oxide using reduced amounts of water
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Hydration of various kinds of nitriles could efficiently be promoted by amorphous MnO2 using reduced amounts of water (2 equiv or less), giving the corresponding primary amides in moderate to high yields. The observed catalysis was truly heterogeneous, and the retrieved MnO2 could be reused without an appreciable loss of its high catalytic performance.
- Yamaguchi, Kazuya,Wang, Ye,Kobayashi, Hiroaki,Mizuno, Noritaka
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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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- Amidation of aldehydes using mono-cationic half-sandwich rhodium(III) complexes with functionalized phenylhydrazone ligands
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A series of mono-cationic half-sandwich rhodium(III) complexes have been synthesized in methanol using phenylhydrazone-derived ligands (L1–L6) and the starting precursor [(η5-C5Me5)2Rh2(μ-Cl)2Cl2] in a 2:1 molar ratio. The N,N′-phenylhydrazone complexes have been isolated as tetraphenylborate salts. All complexes were characterized by elemental analysis, FT-IR, UV–visible, NMR spectroscopy and mass spectrometry. The molecular structure of complex [(η5-C5Me5)Rh(L1)Cl](BPh4) (1) was confirmed by single-crystal X-ray structure analysis. Complex [(η5-C5Me5)Rh(L3)Cl](BPh4) (3) was used as an efficient catalyst for the amide formation reaction, with up to 99% conversion after 2 h in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate.
- Devika, Neelakandan,Ananthalakshmi, Subbiah,Raja, Nandhagopal,Gupta, Gajendra,Therrien, Bruno
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- Proton and carbon-13 NMR studies of conformational preferences in N-(2-pyridinyl)-2-pyridinecarboxamides
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The 1H and 13C NMR spectra, molecular conformation and intermolecular association of N-(2-pyridinyl)-2-pyridinecarboxamides and 2-pyridinecarboxamide are discussed. The 1H NMR spectra have been analyzed with the aid of COSY spectra and the 13C spectra with the aid of HETCOR, proton coupled spectra and 13C-1H coupling constants. In concentrated CDCl3 solution, N-(2-pyridinyl)-2-pyridinecarboxamides dimerise by intermolecular association
- Singha, Netai C.,Sathyanarayana
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- Direct Oxidative Amination of the Methyl C-H Bond in N-Heterocycles over Metal-Free Mesoporous Carbon
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Direct oxidative amination of the sp3C-H bond is an attractive synthesis route to obtain amides. Conventional catalytic systems for this transformation are based on transition metals and complicated synthesis processes. Herein, direct and efficient oxidative amination of the methyl C-H bond in a wide range of N-heterocycles to access the corresponding amides over metal-free porous carbon is successfully developed. To understand the fundamental structure-activity relationships of carbon catalysts, the surface functional groups and the graphitization degree of porous carbon have been purposefully tailored through doping with nitrogen or phosphorus. The results of characterization, kinetic studies, liquid-phase adsorption experiments, and theoretical calculations indicate that the high activity of the carbon catalyst is attributed to the synergistic effect of surface acidic functional groups (hydroxyl/carboxylic acid/phosphate) and more graphene edge structures exposed on the surface of carbon materials with a high graphitization degree, in which the role of acidic functional groups is to adsorb the substrate molecule and the role of the graphene edge structure is to activate O2
- Long, Xiangdong,Wang, Jia,Gao, Guang,Nie, Chao,Sun, Peng,Xi, Yongjie,Li, Fuwei
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p. 10902 - 10912
(2021/09/08)
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- Ru(ii)- And Ru(iv)-dmso complexes catalyze efficient and selective aqueous-phase nitrile hydration reactions under mild conditions
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New water-soluble ruthenium(ii)- and ruthenium(iv)-dmso complexes [RuCl2(dmso)2(NH3)(CH3CN)] (1), [RuCl2(dmso)3(CH3CN)] (2), and [RuCl2(dmso)3(NH3)]·PF6·Cl (3) have been synthesized and characterized using elemental analyses, IR, 1H and 31P NMR, and electronic absorption spectroscopy. The molecular structures of complexes 1-3 were determined crystallographically. The reactivity of complexes 1-3 has been tested for aqueous-phase nitrile hydration at 60 °C in air, and good efficiency and selectivity are shown for the corresponding amide derivatives. Best performance is achieved with complex 3. Amide conversions of 56-99% were obtained with a variety of aromatic, alkyl, and vinyl nitriles. The reaction tolerated hydroxyl, nitro, bromo, formyl, pyridyl, benzyl, alkyl, and olefinic functional groups. Amides were isolated by simple decantation from the aqueous-phase catalyst. A catalyst loading down to 0.0001 mol% was examined and turnover numbers as high as 990?000 were observed. The catalyst was stable for weeks in solution and could be reused more than seven times without significant loss in catalytic activity. The gram-scale reaction was also performed to produce the desired product in high yields. This journal is
- Dubey, Santosh Kumar,Kaur, Gurmeet,Rath, Nigam P.,Trivedi, Manoj
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p. 17339 - 17346
(2021/10/08)
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- Synthesis of New Ruthenium-CAP Complexes and Use as Catalysts for Benzonitrile Hydration to Benzamide
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The new bimetallic [Ru2(μ-Cl)3(CAP)6]Cl (1) and monometallic cis,cis,trans-[RuCl2(dmso-S)2(CAP)2] (2) complexes, bearing the water soluble cage-like phosphine CAP (1,4,7-triaza-9-phosphatricyclo[5.3.2.1]tridecane), were synthesized and characterized in solution by NMR spectroscopy and ESI-MS spectrometry. The complexes, endowed with high solubility and stability in water, were applied as catalysts for the proof-of-concept hydration of benzonitrile to benzamide in neat water at 100 °C, achieving high conversions with only 1 mol % of catalyst, both in single runs and in catalyst recycling experiments.
- Guerriero, Antonella,Peruzzini, Maurizio,Gonsalvi, Luca
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p. 4669 - 4675
(2021/11/16)
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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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- Aerobic oxidation of primary amines to amides catalyzed by an annulated mesoionic carbene (MIC) stabilized Ru complex
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Catalytic aerobic oxidation of primary amines to the amides, using the precatalyst [Ru(COD)(L1)Br2] (1) bearing an annulated π-conjugated imidazo[1,2-a][1,8]naphthyridine-based mesoionic carbene ligand L1, is disclosed. This catalytic protocol is distinguished by its high activity and selectivity, wide substrate scope and modest reaction conditions. A variety of primary amines, RCH2NH2 (R = aliphatic, aromatic and heteroaromatic), are converted to the corresponding amides using ambient air as an oxidant in the presence of a sub-stoichiometric amount of KOtBu in tBuOH. A set of control experiments, Hammett relationships, kinetic studies and DFT calculations are undertaken to divulge mechanistic details of the amine oxidation using 1. The catalytic reaction involves abstraction of two amine protons and two benzylic hydrogen atoms of the metal-bound primary amine by the oxo and hydroxo ligands, respectively. A β-hydride transfer step for the benzylic C-H bond cleavage is not supported by Hammett studies. The nitrile generated by the catalytic oxidation undergoes hydration to afford the amide as the final product. This journal is
- Yadav, Suman,Reshi, Noor U Din,Pal, Saikat,Bera, Jitendra K.
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p. 7018 - 7028
(2021/11/17)
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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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- Method for synthesizing amide compound by catalyzing heterocyclic compound through non-metal porous carbon
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The invention discloses a method for synthesizing an amide compound by catalyzing a heterocyclic compound through non-metal porous carbon. The preparation method comprises the following steps of: taking a methyl-containing heterocyclic compound as a raw material, adopting a small molecular nitrogen-containing compound as a nitrogen source, and taking non-metal porous carbon as a catalyst, carryingout reaction for 0.5-48h in an oxidizing atmosphere under a pressure of 0.1-10MPa and a temperature of 50-200DEG C to obtain the amide compound. The method starts from an sp3 C-H bond, adopts oxygenor air serves as an oxidizing agent, takes the nitrogen-containing organic small molecule as a nitrogen source, and employs porous carbon as the catalyst to synthesize the amide compound by one step,and the whole catalytic reaction process has the advantages of high efficiency, short route, low cost, easily available raw materials, etc. In addition, the porous carbon catalyst can be recycled, andmeets the technical requirements of China for establishing a green ecological society.
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Paragraph 0020; 0028-0029
(2020/06/20)
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- Ru-based complexes as heterogeneous potential catalysts for the amidation of aldehydes and nitriles in neat water
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Five novel heterogeneous mononuclear complex-anchored Ru(III) have been efficiently sono-synthesized and characterized by utilizing several analytical techniques. The assembled complexes could be utilized as effective, robust and recyclable (up to eight consecutive runs) catalysts for one-pot transformation of a vast array of nitriles and aldehydes to primary amides in H2O under aerobic conditions. Moreover, some unreported di- and tetra-amide derivatives were obtained also under the optimal conditions. The results of ICP/OES analysis demonstrated that there is no detected leaching of the recycled catalyst, which suggests the real heterogeneity of the present protocol. The present Ru-complexes exhibited superiority compared to other reported catalysts for amide preparation in terms of low catalyst load, short reaction time, low operating temperature, no hazardous additives required, and high values of TON (990) and TOF (1980 h11).
- Arafa, Wael Abdelgayed Ahmed
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p. 1056 - 1064
(2020/11/09)
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- Synthesis, characterization and crystal structure of 2-pyridinecarboxamide
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2-Pyridinecarboxamide was synthesized from 2-picoline through two-steps reaction. Initially, 2-picoline was converted into 2-cyanopyridine by ammoxidation in a stainless-steel fixed-bed reactor at 370 oC with V2O5 loaded on TiO2 as catalyst. The 2-cyanopyridine was transformed into 2-pyridinecarboxamide through oxidation hydrolysis in basic solution using MnO2 as oxidant at 70 oC. The final product was characterized by FT-IR, NMR and UV-visible analysis, and 2-pyridinecarboxamide in the final product was determined using HPLC. The crystal structure of 2-pyridinecarboxamide was investigated using X-ray diffraction and SHELX 2018/3 (sh) software and the result indicated that 2-pyridinecarboxamide crystallized in the monoclinic system, space group P21/n with a = 5.207(2), b = 7.097(3), c = 16.243(6) ?, V = 595.7 (4) ?3; Z = 4.
- Sun, Kai-Jin,Cai, Zhao-Sheng
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p. 195 - 198
(2019/12/02)
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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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- Method for preparing aryl primary amide by adopting metal-catalyzed one-pot method
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The invention discloses a method for synthesizing aryl primary amide by adopting a metal-catalyzed one-pot method. The method comprises the steps of: taking aryl bromidess as raw materials, allowing the aryl bromidess to react with a cyanide source under the action of a palladium catalyst, substituting bromine on an aromatic ring with cyano to obtain cyano aromatic hydrocarbon, directly adding anaqueous solution of alkali into the reaction solution without aftertreatment, and carrying out hydrolysis reaction to obtain aryl primary amide. Compared with the prior art, the method for preparing aryl primary amide from the aryl bromides has the advantages of the short synthesis route, fewer reaction steps, simple operation, mild conditions, the high conversion rate, low toxicity and industrialproduction potential.
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Paragraph 0026-0028
(2020/04/06)
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- Method for preparing amide compounds by using supported metal oxide catalytic material
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The invention relates to a catalyst for preparing amide compounds, and aims to provide a method for preparing amide compounds by using a supported metal oxide catalytic material. The method comprisesthe following steps: uniformly mixing a solvent, water, an organic nitrile compound and the catalytic material; performing a reaction at 50-180 DEG C for 0.5-48 h; and hydrating and converting the organic nitrile compound into the corresponding amide compounds through the catalytic hydration effect of the catalyst in the reaction process. Adsorption and activation of the catalytic material to water molecules can be effectively regulated by regulating metal components loaded on the catalytic material and a catalytic material carrier, so that important amide compounds in chemical and agricultural processes are efficiently prepared. The provided method for preparing the amide compounds is effect, and has the advantages of high atom utilization rate in the reaction process, low reaction temperature, no additional reaction assistant in the synthesis process, no generation of toxic or harmful byproducts after the reaction, and green and environment-friendly synthesis process.
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Paragraph 0142; 0143
(2020/06/05)
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- Method for preparing amide compounds by catalyzing organic nitrile hydration with oxide material
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The invention relates to a catalyst for preparing amide compounds, and aims to provide a method for preparing amide compounds by catalyzing organic nitrile hydration with an oxide material. The methodcomprises the following steps: adding a solvent, an organic nitrile substrate, water and a catalyst into a sealable reaction container, and uniformly mixing; performing a reaction at 50-180 DEG C for0.5-24 h; and catalyzing hydration in the reaction process to make the nitrile compounds finally hydrated and converted into corresponding amide compounds. The catalyst is cheap and easy to obtain, and no precious metal is used, so that the preparation cost of the catalyst is low, and large-scale production of the catalyst is facilitated. In the reaction process, the atom utilization rate is high, the reaction temperature is low, no additional reaction assistant is needed in the synthesis process, no toxic or harmful byproduct is generated after the reaction, and the whole synthesis process is green and environmentally friendly.
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Paragraph 0134-0135
(2020/06/05)
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- Half-Sandwich Iridium Complexes for the One-Pot Synthesis of Amides: Preparation, Structure, and Diverse Catalytic Activity
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Several types of air-stable N,O-coordinate half-sandwich iridium complexes containing Schiff base ligands with the general formula [Cp*IrClL] were synthesized in good yields. These stable iridium complexes displayed a good catalytic efficiency in amide synthesis. A variety of amides with different substituents were obtained in a one-pot procedure with excellent yields and high selectivities through the amidation of aldehydes with NH2OHHCl and nitrile hydration under the catalysis of complexes 1-4. The excellent and diverse catalytic activity, mild conditions, broad substance scope, and environmentally friendly solvent make this system potentially applicable in industrial production. Half-sandwich iridium complexes 1-4 were characterized by NMR, elemental analysis, and IR techniques. Molecular structures of complexes 2 and 3 were confirmed by single-crystal X-ray analysis.
- Fan, Xiao-Nan,Deng, Wei,Liu, Zhen-Jiang,Yao, Zi-Jian
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p. 16582 - 16590
(2020/11/13)
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- A State-of-the-Art Heterogeneous Catalyst for Efficient and General Nitrile Hydrogenation
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Cobalt-doped hybrid materials consisting of metal oxides and carbon derived from chitin were prepared, characterized and tested for industrially relevant nitrile hydrogenations. The optimal catalyst supported onto MgO showed, after pyrolysis at 700 °C, magnesium oxide nanocubes decorated with carbon-enveloped Co nanoparticles. This special structure allows for the selective hydrogenation of diverse and demanding nitriles to the corresponding primary amines under mild conditions (e.g. 70 °C, 20 bar H2). The advantage of this novel catalytic material is showcased for industrially important substrates, including adipodinitrile, picolinonitrile, and fatty acid nitriles. Notably, the developed system outperformed all other tested commercial catalysts, for example, Raney Nickel and even noble-metal-based systems in these transformations.
- Formenti, Dario,Mocci, Rita,Atia, Hanan,Dastgir, Sarim,Anwar, Muhammad,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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supporting information
p. 15589 - 15595
(2020/10/02)
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- Transamidation for the Synthesis of Primary Amides at Room Temperature
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Various primary amides have been synthesized using the transamidation of various tertiary amides under metal-free and mild reaction conditions. When (NH4)2CO3 reacts with a tertiary amide bearing an N-electron-withdrawing substituent, such as sulfonyl and diacyl, in DMSO at 25 °C, the desired primary amide product is formed in good yield with good funcctional group tolerance. In addition, N-tosylated lactam derivatives afforded their corresponding N-tosylamido alkyl amide products via a ring opening reaction.
- Chen, Jiajia,Lee, Sunwoo,Xia, Yuanzhi
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supporting information
(2020/05/05)
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- Aerobic oxidation of primary benzylic amines to amides and nitriles catalyzed by ruthenium carbonyl clusters carrying N,O-bidentate ligands
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Four trinuclear ruthenium carbonyl clusters, (6-BrPyCHRO)2Ru3(CO)8 (R = 4-OCH3C6H4, 1a; R = 4-BrC6H4, 1b) and (2-OC6H4-HCN-C6H4R)2Ru3(CO)8 (R = 4-OCH3, 2a; R = 4-Br, 2b), were synthesized from the reactions of Ru3(CO)12 with the corresponding N,O-bidentate ligands (two pyridyl alcohols and two Schiff bases) respectively in a ratio of 1:2. Three new complexes 1b, 2a and 2b have been fully characterized by elemental analysis, FT-IR, NMR and X-ray crystallography. The catalytic activity of these ruthenium complexes for the aerobic oxidation of primary benzylic amines to amides and nitriles in the presence of t-BuOK was investigated, of which the Schiff base complex 2a was found to exhibit the highest activity.
- Dong, Qing,Han, Zhangang,Hao, Zhiqiang,Li, Ying,Lin, Jin,Lu, Guo-Liang,Meng, Lizhen,Yan, Xinlong
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p. 3480 - 3487
(2020/04/02)
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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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- Preparation method of aromatic amide compound
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The present invention provides a preparation method of an aromatic amide compound. In an organic solvent, under the effect of a catalyst, an aromatic acid compound and an amine source are subjected toa dehydration reaction to obtain the aromatic amide compound, wherein the aromatic acid compound is an aromatic acid, a substituted aromatic acid, a heterocyclic aromatic acid or a substituted heterocyclic aromatic acid; and the substituent group of amide is any substituent group of H, a C1-C8 straight-chain alkyl or branched-chain alkyl group, a benzene ring or an aromatic ring. The aromatic amide compound is an important chemical intermediate, and the synthesis method is mild in reaction condition and high in yield.
- -
-
Paragraph 0046-0047
(2020/07/15)
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- Metal-free nitrogen -doped carbon nanosheets: A catalyst for the direct synthesis of imines under mild conditions
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Herein, a highly stable, porous, multifunctional and metal-free catalyst was developed, which exhibited significant catalytic performance in the oxidation of amines and transfer hydrogenation of nitriles under mild conditions; this could be attributed to the presence of numerous active sites and their outstanding BET surface area. The obtained results showed that most of the yields of imines exceeded 90%, and the cycling performance of the catalyst could be at least seven runs without any decay in the reaction activity, which could be comparable to those of metal catalysts. Subsequently, a kinetic study has demonstrated that the apparent activation energy for the direct synthesis of imines from amines is 67.39 kJ mol-1, which has been performed to testify that the catalytic performances are rational. Via catalyst characterizations and experimental data, graphitic-N has been proven to be the active site of the catalyst. Hence, this study is beneficial to comprehend the mechanism of action of a metal-free N-doped carbon catalyst in the formation of imines.
- Wang, Kaizhi,Jiang, Pengbo,Yang, Ming,Ma, Ping,Qin, Jiaheng,Huang, Xiaokang,Ma, Lei,Li, Rong
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p. 2448 - 2461
(2019/05/17)
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- Hydration of nitriles using a metal-ligand cooperative ruthenium pincer catalyst
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Nitrile hydration provides access to amides that are important structural elements in organic chemistry. Here we report catalytic nitrile hydration using ruthenium catalysts based on a pincer scaffold with a dearomatized pyridine backbone. These complexes catalyze the nucleophilic addition of H2O to a wide variety of aliphatic and (hetero)aromatic nitriles in tBuOH as solvent. Reactions occur under mild conditions (room temperature) in the absence of additives. A mechanism for nitrile hydration is proposed that is initiated by metal-ligand cooperative binding of the nitrile.
- Guo, Beibei,Otten, Edwin,De Vries, Johannes G.
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p. 10647 - 10652
(2019/12/02)
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- Activation of nitriles by silver(I) N-heterocyclic carbenes: An efficient on-water synthesis of primary amides
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A first example of silver(I) N-heterocyclic carbene (Ag(I)-NHC) catalyzed on-water synthesis of primary amides by hydration of nitriles under mild reaction conditions is described. This organometallic catalytic system has excellent tolerance for various homo-aromatic, hetero-aromatic and aliphatic nitriles to afford primary amides in good yields in neat water.
- Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Kankala, Shravankumar,Vadde, Ravindhar,Vasam, Chandra Sekhar
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supporting information
p. 2637 - 2641
(2019/03/21)
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- Trash to treasure: Eco-friendly and practical synthesis of amides by nitriles hydrolysis in WepPA
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The hydration of nitriles to amides in a water extract of pomelo peel ash (WEPPA) was realized with moderate to excellent yields without using external transition metals, bases or organic solvents. This reaction features a broad substrate scope, wide functional group tolerance, prominent chemoselectivity, and good reusability. Notably, a magnification experiment in this bio-based solvent at 100 mmol further demonstrated its practicability.
- Sun, Yajun,Jin, Weiwei,Liu, Chenjiang
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supporting information
(2019/11/11)
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- A method for utilizing 2 - OP rectification residue preparing 2 - aminopyridine method (by machine translation)
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The invention belongs to the field of organic chemistry, and in particular relates to a method for utilizing 2 - OP rectification residue preparing 2 - aminopyridine method, is a chemical by-product recycle of efficient utilization of the new method. Comprises the following steps: by phosphorylation zeolite and/or phosphorylated the silica gel for the 2 - OP rectification residue catalytic cracking of the role of the high-boiling, boiling residues depolymerized and into relatively low boiling point of pyridine - 2 - carboxamide, and the use of boiling point difference, by reduced pressure distillation method to make the pyridine - 2 - carboxamide with 2 - OP rectification residue the preliminary separation of high-boiling by the pyridine - 2 - carboxamide crude; under the protection of nitrogen, through the Huffman degradation by the reaction of 2 - aminopyridine crude product; the resulting 2 - aminopyridine crude product through the recrystallized or purified by distillation under reduced pressure. The invention through the "one-pot" will be its prepared pyridine - 2 - carboxamide crude product is converted into the 2 - aminopyridine method, in order to promote 2 - OP (i.e. 2 - cyano pyridine) of clean production and production process of the green, and to promote the efficient utilization of resources. (by machine translation)
- -
-
Paragraph 0018; 0021
(2019/11/14)
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- A metal-free approach to access ketones, amides, and nitriles employing TBAI/TBHP oxidative system in water
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Hydrocarbons, benzylamines, and heteroaromatic-bearing amines have been efficiently employed as substrates in allylic and benzylic oxidations via C(sp3)–H bond activation by TBAI/TBHP in water. This operationally simple method allows access to ketones, nitriles, and amides in moderate to high yields and a regio- and chemoselective late-stage functionalization.
- Gomes, Suzane Quintana,Salles, Airton G.
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supporting information
p. 3389 - 3399
(2019/11/05)
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- Ionic liquid catalysed aerobic oxidative amidation and thioamidation of benzylic amines under neat conditions
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Tetrabutylammonium hydroxide (TBAOH) was discovered as a highly efficient and green catalyst for aerobic oxidation of the α-methylene carbon of primary amines as well as benzylic groups into the corresponding amides and ketones under neat conditions. We described herein, ionic liquid TBAOH catalysed aerobic oxidation of benzyl amines to benzamides and with elemental sulfur; the corresponding benzylbenzothioamides were obtained under metal-free, oxidant-free and base-free conditions. Applicability at the gram scale for the synthesis of the desired amides/ketones is also demonstrated with the present protocol.
- Joshi, Abhisek,Kumar, Rahul,Semwal, Rashmi,Rawat, Deepa,Adimurthy, Subbarayappa
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supporting information
p. 962 - 967
(2019/03/11)
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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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- Half-sandwich ruthenium(II)complexes containing O, N bidentate azo ligands: Synthesis, structure and their catalytic activity towards one-pot conversion of aldehydes to primary amides and transfer hydrogenation of ketones
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The ruthenium(II)complexes of the general formula [Ru(η6?p?cymene)(Cl)(L1?5)](L = O, N-donors of biphenylazo derivatives), formed by reacting 2?(biphenylazo)phenol (HL1 ? HL4)and 1?(biphenylazo)naphthol ligands (HL5)with [{η6?p?cymene)RuCl}2(μ?Cl)2]have been synthesized. The compositions of the complexes have been established by IR, UV–Vis, 1H NMR spectral methods and X-ray crystallography. The synthesized complex could act as an efficient, reusable homogeneous catalyst for transformation of aldehydes to the corresponding primary amides in the presence of NH2OH·HCl, thus resulting an expansion of Beckmann rearrangement. The effect of solvent, base, temperature, time, catalyst loading and recyclability was also investigated. They also effectively catalyze the transfer hydrogenation reaction of various ketones with 2-propanol.
- Nandhini, Raja,Venkatachalam, Galmari
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- Ti-superoxide catalyzed oxidative amidation of aldehydes with saccharin as nitrogen source: Synthesis of primary amides
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A new heterogeneous catalytic system (Ti-superoxide/saccharin/TBHP) has been developed that efficiently catalyzes oxidative amidation of aldehydes to produce various primary amides. The protocol employs saccharin as amine source and was found to tolerate a wide range of substrates with different functional groups. Moderate to excellent yields, catalyst reusability and operational simplicity are the main highlights. A possible mechanism and the role of the catalyst in oxidative amidation have also been discussed.
- Kamble, Rohit B.,Mane, Kishor D.,Rupanawar, Bapurao D.,Korekar, Pranjal,Sudalai,Suryavanshi, Gurunath
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p. 724 - 728
(2020/01/23)
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- Nitrile Hydration Reaction Using Copper Iodide/Cesium Carbonate/DBU in Nitromethane-Water
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The catalytic nitrile hydration (amide formation) in a copper iodide/cesium carbonate/1,8-diazabicyclo[5.4.0]undec-7-ene/nitromethane-water system is described. The protocol is robust and reliable; it can be applied to a broad range of substrates with high chemoselectivity.
- Kuwabara, Jun,Sawada, Yoshiharu,Yoshimatsu, Mitsuhiro
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supporting information
p. 2061 - 2065
(2018/09/14)
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- Mn(i) organometallics containing the iPr2P(CH2)2PiPr2 ligand for the catalytic hydration of aromatic nitriles
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The first example of a homogeneous hydration of aromatic nitriles catalyzed by manganese molecular compounds is reported. The Mn(i) organometallics fac-[(CO)3Mn(dippe)(Z)]1-nX1-n (n = 0, 1; Z = Br, OTf, PhCN; X = OTf) were synthesized and characterized, and their reactivity was studied. The species fac-[(CO)3Mn(dippe)(OTf)] (2) was used as a catalyst precursor for the selective hydration of benchmark benzonitrile (2 mol% 2, THF/H2O 1:2 v/v, 18 h, 100 °C) to produce benzamide in 90% isolated yield. A series of (hetero)aromatic nitriles were hydrated to synthesize the corresponding amides in very good to excellent yields (88-94%). Isotopic labeling studies accounted for a proton transfer as the rate-determining step.
- Gardu?o, Jorge A.,Arévalo, Alma,Flores-Alamo, Marcos,García, Juventino J.
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p. 2606 - 2616
(2018/05/30)
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- A continuous-flow synthesis of primary amides from hydrolysis of nitriles using hydrogen peroxide as oxidant
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A continuous-flow synthesis of primary amides from hydrolysis of nitriles using hydrogen peroxide as oxidant has been developed. Using this procedure, a variety of nitriles could be smoothly transformed into the desired primary amides in good to excellent yields. The mild reaction conditions and the flowing reaction system greatly improved the safety and make the reaction easy to scale up.
- Zhan, Wei,Ji, Ling,Ge, Ze-mei,Wang, Xin,Li, Run-tao
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p. 1527 - 1532
(2018/02/21)
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- Direct Catalytic Synthesis of N-Arylcarbamates from CO2, Anilines and Alcohols
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The direct catalytic synthesis of carbamates from CO2, amines and methanol was achieved by controlling both the reaction equilibrium and the reactivity of the three components. The combination of CeO2 and 2-cyanopyridine was an effective catalyst, providing various carbamates including N-arylcarbamates in high selectivities.
- Tamura, Masazumi,Miura, Ayaka,Honda, Masayoshi,Gu, Yu,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 4835 - 4839
(2018/10/15)
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- METHOD FOR PRODUCING CARBAMATE
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PROBLEM TO BE SOLVED: To provide a method for producing carbamate in which a high yield can be obtained and the amount of by-products produced can be reduced. SOLUTION: In the method, carbamate is synthesized using at least one member selected from the group consisting of amine and derivative thereof, alcohol having 3 or more carbon atoms and carbon dioxide as a raw material, cerium oxide as a catalyst, and 2-cyanopyridine as a dehydrating agent. By using an alcohol having 3 or more carbon atoms, a high yield can be obtained and the amount of by-products produced can be reduced. In addition, the pressure of carbon dioxide can be lowered and the production can be of ease. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2018,JPO&INPIT
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Paragraph 0041; 0043
(2018/10/16)
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- Vinylogous Blaise Reaction: Conceptually New Synthesis of Pyridin-2-ones
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A conceptually new synthesis of pyridine rings by a [C 4 + CN] assembly has been developed by applying a vinylogous version of the classic Blaise reaction. The zinc-mediated reaction of (het)aryl or alkyl nitriles with ethyl-4-bromocrotonate pr
- Rao, H. Surya Prakash,Muthanna, Nandurka,Padder, Ashiq Hussain
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supporting information
p. 1649 - 1653
(2018/06/26)
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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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- Metal-Free Thermal Activation of Molecular Oxygen Enabled Direct α-CH2-Oxygenation of Free Amines
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Direct oxidation of α-CH2 group of free amines is hard to achieve due to the higher reactivity of amine moiety. Therefore, oxidation of amines involves the use of sophisticated metallic reagents/catalyst in the presence or absence of hazardous oxidants under sensitive reaction conditions. A novel method for direct C-H oxygenation of aliphatic amines through a metal-free activation of molecular oxygen has been developed. Both activated and unactivated free amines were oxygenated efficiently to provide a wide variety of amides (primary, secondary) and lactams under operationally simple conditions without the aid of metallic reagents and toxic oxidants. The method has been applied to the synthesis of highly functionalized amide-containing medicinal drugs, such as O-Me-alibendol and -buclosamide.
- Ghosh, Santanu,Jana, Chandan K.
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p. 260 - 266
(2018/02/19)
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- The use of a manganese oxide of the amine of preparation of amides oxidation method (by machine translation)
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The invention relates to the synthesis of amide compound catalyst, and aims at providing a oxidation using manganese oxide of the amine of preparation of amides method. Including: the pressure in the container adding organic solvent, organic amine substrate and catalyst and uniformly mixed, and then filled with oxygen, the reaction process through the catalyst in the catalytic oxidation, organic amine substrate of alpha nanotube growing C=O double bond is formed, thereby obtaining the amide group and finally generates the amide compound. The invention relates to catalyst of the cheap and easy to obtain, in the catalyst of gas relates to oxide, unused to any noble metal, so that the preparation cost of the catalyst is relatively low, conducive to the realization of large-scale production of the catalyst. The method the reaction temperature is low, and in the course of synthesizing reaction assistant without additional added, after reaction without harmful toxic by-product to produce, in the whole synthesis process is environment-friendly. (by machine translation)
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Paragraph 0091; 0092
(2018/10/19)
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- Metal-Free Nitrogen- and Boron-Codoped Mesoporous Carbons for Primary Amides Synthesis from Primary Alcohols via Direct Oxidative Dehydrogenation
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Metal-free catalysts show environmental friendliness and cost-effectiveness, as well as less susceptibility to poisoning over metal and metal oxide catalysts. In this respect, we present the synthesis and characterization of metal-free mesoporous nitrogen- and boron-codoped nanocarbon (meso-N,B/C), which exhibits good catalytic performance with conversion of 89% and selectivity of 83% toward amide synthesis from primary alcohols using NH4OAc as an ammonia resource under an oxygen atmosphere. The facile codoping synthetic strategy was executed by pyrolysis of nitrogen-enriched ligand 4,5-diazafluorene-9-one azine (DAA) and H3BO3 as a nitrogen and boron content modulator, respectively. Significantly, control experiments revealed that the reaction proceeded through direct oxidative dehydrogenation of hemiaminal after aldehyde-ammonia condensation, which was remarkably different from that in the previous literature. Density functional theory (DFT) calculations further demonstrate that the selective preference for benzamide largely benefits from the strong adsorption and enhanced activity of oxygen molecules via the interaction with a B atom doped in the catalyst. The active sites in the meso-N,B/C catalyst are proposed to be B atom bonded with N within the graphitic carbon sheets. This founding opens up avenues for the development of modified carbon materials on metal-free catalysis.
- Shang, Sensen,Chen, Pei-Pei,Wang, Lianyue,Lv, Ying,Li, Wei-Xue,Gao, Shuang
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p. 9936 - 9944
(2018/10/15)
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- Stable and reusable nanoscale Fe2O3-catalyzed aerobic oxidation process for the selective synthesis of nitriles and primary amides
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The sustainable introduction of nitrogen moieties in the form of nitrile or amide groups in functionalized molecules is of fundamental interest because nitrogen-containing motifs are found in a large number of life science molecules, natural products and materials. Hence, the synthesis and functionalization of nitriles and amides from easily available starting materials using cost-effective catalysts and green reagents is highly desired. In this regard, herein we report the nanoscale iron oxide-catalyzed environmentally benign synthesis of nitriles and primary amides from aldehydes and aqueous ammonia in the presence of 1 bar O2 or air. Under mild reaction conditions, this iron-catalyzed aerobic oxidation process proceeds to synthesise functionalized and structurally diverse aromatic, aliphatic and heterocyclic nitriles. Additionally, applying this iron-based protocol, primary amides have also been prepared in a water medium.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Sharif, Muhammad,Kalevaru, Narayana V.,Jagadeesh, Rajenahally V.
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supporting information
p. 266 - 273
(2018/01/12)
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- Hemilability-Driven Water Activation: A NiII Catalyst for Base-Free Hydration of Nitriles to Amides
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The NiII complex 1 containing pyridyl- and hydroxy-functionalized N-heterocyclic carbenes (NHCs) is synthesized and its catalytic utility for the selective nitrile hydration to the corresponding amide under base-free conditions is evaluated. The title compound exploits a hemilabile pyridyl unit to interact with a catalytically relevant water molecule through hydrogen-bonding and promotes a nucleophilic water attack to the nitrile. A wide variety of nitriles is hydrated to the corresponding amides including the pharmaceutical drugs rufinamide, Rifater, and piracetam. Synthetically challenging α-hydroxyamides are accessed from cyanohydrins under neutral conditions. Related catalysts that lack the pyridyl unit (i.e., compounds 2 and 4) are not active whereas those containing both the pyridyl and the hydroxy or only the pyridyl pendant (i.e., compounds 1 and 3) show substantial activity. The linkage isomer 1′ where the hydroxy group is bound to the metal instead of the pyridyl group was isolated under different crystallization conditions insinuating a ligand hemilabile behavior. Additional pKa measurements reveal an accessible pyridyl unit under the catalytic conditions. Kinetic studies support a ligand-promoted nucleophilic water addition to a metal-bound nitrile group. This work reports a Ni-based catalyst that exhibits functional hemilability for hydration chemistry.
- Singh, Kuldeep,Sarbajna, Abir,Dutta, Indranil,Pandey, Pragati,Bera, Jitendra K.
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p. 7761 - 7771
(2017/06/06)
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