- Evidence against an Alternative Mechanism for a Self-Replicating System
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A recent paper by Menger et al. described experimental and computational work related to our self-replicating system and concluded that amide catalysis - either external or internal - is the cause of observed rate enhancements.Herein we show that the proporsal of Menger et al. is inconsistent with published data, that their conclusions overreach the data afforded by their experiments, and that the step which they modeled is likely irrelevant to the autocatalytic nature of the system.We present new results and a refined mechanism in which the transition state is stabilized not by amides but by template-based recognition, the hallmark of self-replicating systems.
- Wintner, Edward A.,Tsao, Belinda,Rebek, Julius
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- Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
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A cheap, facile and metal-free photochemical protocol for the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a drug against depression and social anxiety. Extended and detailed mechanistic studies have been conducted, in order to determine a plausible mechanism for the reaction.
- Nikitas, Nikolaos F.,Apostolopoulou, Mary K.,Skolia, Elpida,Tsoukaki, Anna,Kokotos, Christoforos G.
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p. 7915 - 7922
(2021/05/03)
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- Efficient cleavage of tertiary amide bonds: Via radical-polar crossover using a copper(ii) bromide/Selectfluor hybrid system
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A novel approach for the efficient cleavage of the amide bonds in tertiary amides is reported. Based on the selective radical abstraction of a benzylic hydrogen atom by a CuBr2/Selectfluor hybrid system followed by a selective cleavage of an N-C bond, an acyl fluoride intermediate is formed. This intermediate may then be derivatized in a one-pot fashion. The reaction proceeds under mild conditions and exhibits a broad substrate scope with respect to the tertiary amide moiety as well as to nitrogen, oxygen, and carbon nucleophiles for the subsequent derivatization. Mechanistic studies suggest that the present reaction proceeds via a radical-polar crossover process that involves benzylic carbon radicals generated by the selective radical abstraction of a benzylic hydrogen atom by the CuBr2/Selectfluor hybrid system. Furthermore, a synthetic application of this method for the selective cleavage of peptides is described. This journal is
- Maruoka, Keiji,Matsumoto, Akira,Wang, Zhe
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p. 12323 - 12328
(2020/12/08)
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- Nickel-catalyzed reductive amidation of aryl-triazine ethers
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The reaction of activated phenolic compounds, 2,4,6-triaryloxy-1,3,5-triazine (aryl-triazine ethers), with various isocyanates or carbodiimides in the presence of a nickel pre-catalyst resulted in the synthesis of aryl amides in good to excellent yields.
- Heravi, Majid M.,Panahi, Farhad,Iranpoor, Nasser
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supporting information
p. 1992 - 1995
(2020/02/22)
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- The synthesis and structure of pyridine-oxadiazole iridium complexes and catalytic applications: Non-coordinating-anion-tuned selective C–N bond formation
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Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography. The designed iridium complexes revealed surprisingly high catalytic activity in C–N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions. In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols, N,N'-(phenylmethylene)dibenzamide products were unexpectedly isolated under non-coordinating anion conditions, whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions. The mechanism explorations excluded the possibility of “silver effect” (silver-assisted or bimetallic catalysis) and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions. This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C–N bond formation
- Yao, Wei,Zhang, Yilin,Zhu, Haiyan,Ge, Chenyang,Wang, Dawei
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p. 701 - 705
(2019/09/30)
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- Homoleptic Bis(trimethylsilyl)amides of Yttrium Complexes Catalyzed Hydroboration Reduction of Amides to Amines
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Homoleptic lanthanide complex Y[N(TMS)2]3 is an efficient homogeneous catalyst for the hydroboration reduction of secondary amides and tertiary amides to corresponding amines. A series of amides containing different functional groups such as cyano, nitro, and vinyl groups were found to be well-tolerated. This transformation has also been nicely applied to the synthesis of indoles and piribedil. Detailed isotopic labeling experiments, control experiments, and kinetic studies provided cumulative evidence to elucidate the reaction mechanism.
- Ye, Pengqing,Shao, Yinlin,Ye, Xuanzeng,Zhang, Fangjun,Li, Renhao,Sun, Jiani,Xu, Beihang,Chen, Jiuxi
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supporting information
p. 1306 - 1310
(2020/02/22)
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- Nickel-catalyzed aminocarbonylation of aryl halides with carbamoylsilanes: efficient synthesis of secondary (primary) aromatic amides
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A nickel-catalyzed aminocarbonylation of aryl halides using carbamoylsilane as an amide source leading to corresponding secondary or primary aromatic amides has been developed, in which the methoxymethyl and benzyl were used as amino protecting group. The protocol tolerates a broad range of aryl halides bearing different functional groups to afford good yields of aryl amides under mild reaction conditions. The types and the relative positions of substituents on the aryl ring make a notable impact on the coupling efficiency. The plausible mechanism of nickel-catalyzed aminocarbonylation has been suggested.
- Chen, Jianxin,Chen, Wenwen,Wen, Xueping
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- Hydrogen Bond Directed ortho-Selective C?H Borylation of Secondary Aromatic Amides
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Reported is an iridium catalyst for ortho-selective C?H borylation of challenging secondary aromatic amide substrates, and the regioselectivity is controlled by hydrogen-bond interactions. The BAIPy-Ir catalyst forms three hydrogen bonds with the substrate during the crucial activation step, and allows ortho-C?H borylation with high selectivity. The catalyst displays unprecedented ortho selectivities for a wide variety of substrates that differ in electronic and steric properties, and the catalyst tolerates various functional groups. The regioselective C?H borylation catalyst is readily accessible and converts substrates on gram scale with high selectivity and conversion.
- Bai, Shao-Tao,Bheeter, Charles B.,Reek, Joost N. H.
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supporting information
p. 13039 - 13043
(2019/07/31)
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- A solid-supported arylboronic acid catalyst for direct amidation
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An efficient heterogeneous amidation catalyst has been prepared by co-polymerisation of styrene, DVB with 4-styreneboronic acid, which shows wide substrate applicability and higher reactivity than the equivalent homogeneous phenylboronic acid, suggesting potential cooperative catalytic effects. The catalyst can be easily recovered and reused; suitable for use in packed bed flow reactors.
- Du, Yihao,Barber, Thomas,Lim, Sol Ee,Rzepa, Henry S.,Baxendale, Ian R.,Whiting, Andrew
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supporting information
p. 2916 - 2919
(2019/03/27)
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- Ferric(III) Chloride Catalyzed Halogenation Reaction of Alcohols and Carboxylic Acids Using α,α-Dichlorodiphenylmethane
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A new method for chlorination of alcohols and carboxylic acids, using α,α-dichlorodiphenylmethane as the chlorinating agent and FeCl3 as the catalyst, was developed. The method enables conversions of various alcohols and carboxylic acids to their corresponding alkyl and acyl chlorides in high yields under mild conditions. Particulary interesting is the observation that the respective alkyl bromides and iodides can be generated from alcohols when either LiBr or LiI are present in the reaction mixtures.
- Lee, Chang-Hee,Lee, Soo-Min,Min, Byul-Hana,Kim, Dong-Su,Jun, Chul-Ho
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p. 2468 - 2471
(2018/04/25)
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- Diboron-Catalyzed Dehydrative Amidation of Aromatic Carboxylic Acids with Amines
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Tetrakis(dimethylamido)diboron and tetrahydroxydiboron are herein reported as new catalysts for the synthesis of aryl amides by catalytic condensation of aromatic carboxylic acids with amines. The developed protocol is both simple and highly efficient over a broad range of substrates. This method thus represents an attractive approach for the use of diboron catalysts in the synthesis of amides without having to resort to stoichiometric or additional dehydrating agents.
- Sawant, Dinesh N.,Bagal, Dattatraya B.,Ogawa, Saeko,Selvam, Kaliyamoorthy,Saito, Susumu
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supporting information
p. 4397 - 4400
(2018/08/09)
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- N-Heterocyclic Carbene-Mediated Microfluidic Oxidative Electrosynthesis of Amides from Aldehydes
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A flow process for N-Heterocyclic Carbene (NHC)-mediated anodic oxidative amidation of aldehydes is described, employing an undivided microfluidic electrolysis cell to oxidize Breslow intermediates. After electrochemical oxidation, the reaction of the intermediate N-acylated thiazolium cation with primary amines is completed by passage through a heating cell to achieve high conversion in a single pass. The flow mixing regimen circumvented the issue of competing imine formation between the aldehyde and amine substrates, which otherwise prevented formation of the desired product. High yields (71-99%), productivities (up to 2.6 g h-1), and current efficiencies (65-91%) were realized for 19 amides.
- Green, Robert A.,Pletcher, Derek,Leach, Stuart G.,Brown, Richard C. D.
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supporting information
p. 1198 - 1201
(2016/03/15)
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- Computationally motivated synthesis and enzyme kinetic evaluation of N-(β-d-glucopyranosyl)-1,2,4-triazolecarboxamides as glycogen phosphorylase inhibitors
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Following our recent study of N-(β-d-glucopyranosyl)oxadiazolecarboxamides (Polyk et al., Biorg. Med. Chem. 2013, 21, 5738) revealed as moderate inhibitors of glycogen phosphorylase (GP), in silico docking calculations using Glide have been performed on N-(β-d-glucopyranosyl)-1,2,4-triazolecarboxamides with different aryl substituents predicting more favorable binding at GP. The ligands were subsequently synthesized in moderate yields using N-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-tetrazole-5-carboxamide as starting material. Kinetics experiments against rabbit muscle glycogen phosphorylase b (RMGPb) revealed the ligands to be low μM GP inhibitors; the phenyl analogue (Ki = 1 μM) is one of the most potent N-(β-d-glucopyranosyl)-heteroaryl-carboxamide-type inhibitors of the GP catalytic site discovered to date. Based on QM and QM/MM calculations, the potency of the ligands is predicted to arise from favorable intra- and intermolecular hydrogen bonds formed by the most stable solution phase tautomeric (t2) state of the 1,2,4-triazole in a conformationally dynamic system. ADMET property predictions revealed the compounds to have promising pharmacokinetic properties without any toxicity. This study highlights the benefits of a computationally led approach to GP inhibitor design. This journal is
- Begum, Jaida,Varga, Gergely,Docsa, Tibor,Gergely, Pl,Hayes, Joseph M.,Juhsz, Lszl,Somsk, Lszl
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- Ruthenium-catalysed oxidation of alcohols to amides using a hydrogen acceptor
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A wider investigation into the synthesis of secondary amides from primary alcohols using a hydrogen acceptor using commercially available [Ru(p-cymene)Cl2]2 with bis(diphenylphosphino)butane (dppb) as the catalyst. The report looks at over 50 examples with varying functionality and steric bulk, whilst also covering the first reported results using microwave heating to effect the transformation.
- Watson, Andrew J.A.,Wakeham, Russell J.,Maxwell, Aoife C.,Williams, Jonathan M.J.
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supporting information
p. 3683 - 3690
(2014/05/20)
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- Iron pentacarbonyl in alkoxy- and aminocarbonylation of aromatic halides
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We have identified reaction conditions for a Heck-type carbonylation based on [Fe(CO)5]. Preliminary optimization of alkoxycarbonylation on 2-bromonaphthalene defined functioning composition of the reaction mixture which was then applied on a small set of (hetero)aromatic halides. Respective aminocarbonylation of these halides with different amines, including aniline and benzotriazole, was accomplished with reasonable results.
- Babjak, Matej,Caletková, O?ga,?uri?ová, Diana,Gracza, Tibor
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supporting information
p. 2579 - 2584
(2015/01/09)
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
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p. 9349 - 9352
(2014/08/05)
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- Ni-catalyzed direct reductive amidation via C-O bond cleavage
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A novel Ni-catalyzed reductive amidation of C(sp2)-O and C(sp3)-O electrophiles with isocyanates is described. This umpolung reaction allows for an unconventional preparation of benzamides using simple starting materials and easy-to-handle Ni catalysts.
- Correa, Arkaitz,Martin, Ruben
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supporting information
p. 7253 - 7256
(2014/06/09)
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- New synthesis of 3-(β-D-glucopyranosyl)-5-substituted-1,2,4-triazoles, nanomolar inhibitors of glycogen phosphorylase
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O-Perbenzoylated 5-(β-D-glucopyranosyl)tetrazole was reacted with N-benzyl carboximidoyl chlorides to give the corresponding 4-benzyl-3-(β-D- glucopyranosyl)-5-substituted-1,2,4-triazoles. Removal of the O-benzoyl and N-benzyl protecting groups by base catalysed transesterification and catalytic hydrogenation, respectively, furnished a series of 3-(β-D-glucopyranosyl)- 5-substituted-1,2,4-triazoles with aliphatic, mono- and bicyclic aromatic, and heterocyclic substituents in the 5-position. Enzyme kinetic studies revealed these compounds to inhibit rabbit muscle glycogen phosphorylase b: best inhibitors were the 5-(4-aminophenyl)- (Ki 0.67 μM) and the 5-(2-naphthyl)-substituted (Ki 0.41 μM) derivatives. This study uncovered the C-glucopyranosyl-1,2,4-triazoles as a novel skeleton for nanomolar inhibition of glycogen phosphorylase.
- Kun, Sándor,Bokor, éva,Varga, Gergely,Szocs, Béla,Páhi, András,Czifrák, Katalin,Tóth, Marietta,Juhász, László,Docsa, Tibor,Gergely, Pál,Somsák, László
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p. 567 - 579
(2014/04/03)
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- Palladium-catalyzed fluorocarbonylation using N-formylsaccharin as CO source: General access to carboxylic acid derivatives
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N-Formylsaccharin, an easily accessible crystalline compound, has been employed as an efficient CO source in Pd-catalyzed fluorocarbonylation of aryl halides to afford the corresponding acyl fluorides in high yields. The reactions use a near-stoichiometric amount of the CO source (1.2 equiv) and tolerate diverse functional groups. The acyl fluorides obtained could be readily transformed into various carboxylic acid derivatives such as carboxylic acid, esters, thioesters, and amides in a one-pot procedure.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
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supporting information
p. 5370 - 5373
(2013/11/06)
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- Facile preparation of amides from carboxylic acids and amines with ion-supported Ph3P
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Ion-supported Ph3P, 4-(diphenylphosphino)benzyltrimethylammonium bromide (IS-Ph3P), could be used for the facile amidation of a wide range of carboxylic acids with amines in the presence of bromotrichloromethane to provide the corresponding amides in good yields. In the present reaction, the desired amides were obtained in good yields with high purity by simple extraction of the reaction mixture with diethyl ether or chloroform and subsequent removal of the solvent from the extract. Moreover, ion-supported Ph3PO (IS-Ph3PO), which was a co-product derived from IS-Ph3P in the present reductive condensation, was recovered in high yield and could be reduced to IS-Ph3P for reuse in the same amidation of carboxylic acid.
- Kawagoe, Yuhsuke,Moriyama, Katsuhiko,Togo, Hideo
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p. 3971 - 3977
(2013/06/27)
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- Synthesis and research of benzylamides of some isocyclic and heterocyclic acids as potential anticonvulsants
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A series of benzylamides of isocyclic and heterocyclic acids was synthesized and tested in Anticonvulsant Screening Project (ASP) of Antiepileptic Drug Development Program (ADDP) of NIH. Near all synthesized derivatives of heterocyclic acids showed activity. All obtained derivatives of mono- and bicyclic isocyclic acids were inactive. The power of action of heterocyclic acids derivatives seems does not depend upon kind of heteroatom (N, O or S). One of the compounds (2-furoic acid benzylamide (4)) appeared most promising. It showed in minimal clonic seizure (6Hz) test (ASP) in rats after i. p. administration: MES ED50 = 36.5 mg/kg, TOX TD50 = 269.75 mg/kg, and PI = 7.39.
- Strupinska, Marzanna,Rostafinska-Suchar, Grazyna,Pirianowicz-Chaber, Elzbieta,Stables, James P.,Jiang, Jeff,Paruszewski, Ryszard
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p. 681 - 686
(2013/10/01)
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- Additional insights into luminescence process of polycyclic aromatic hydrocarbons with carbonyl groups: Photophysical properties of secondary N -alkyl and tertiary N, N -dialkyl carboxamides of naphthalene, anthracene, and pyrene
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Here we report the substitution effects of N-alkyl and N,N-dialkyl carboxamide groups on the fluorescence properties of polycyclic aromatic hydrocarbon chromophores, so as to control their fluorescence properties. The fluorescence properties of compounds obtained using solvents with different polarities showed very little change, indicating that the modified compounds do not form charge transfer states. TD-DFT calculations and measurements performed at low temperature (78 K) and in viscous solvents revealed that the N-alkyl and N,N-dialkyl carboxamide groups tend to reduce the contributions from intersystem crossing and increase those from internal conversion. Considering that the fluorescence mechanism of low-fluorescence carbonyl compounds such as aldehyde and ketone is dominated by intersystem crossing and that of high-luminescence carbonyl compounds such as carboxylic acid and ester is dominated by a radiative process, it can be said that the photophysical process of N-alkyl and N,N-dialkyl carboxamides is novel. In addition, the calculation results for excited states indicated that such contributions can be controlled by selecting the appropriate polycyclic aromatic hydrocarbon or amide structure, in addition to solvent viscosity and temperature.
- Niko, Yosuke,Hiroshige, Yuki,Kawauchi, Susumu,Konishi, Gen-Ichi
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experimental part
p. 3986 - 3996
(2012/06/29)
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- Mild conversion of esters lacking acidic α-hydrogens into amides via samarium(III) tris[hexamethyldisilazide] and amines
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Samarium(III) tris[hexamethyldisilazide] (Sm[(Me3Si) 2N]3 = Sm[HMDS]3) promotes the direct conversion of an ester admixed with an amine into the corresponding carboxamide under exceptionally mild conditions (≤0°) and in high yields. Only a slight excess of amine and the lanthanide complex are required to effect complete conversion of the ester into the amide. Esters with acidic α-hydrogens undergo a competing Claisen-like condensation along with the desired conversion into amides. Georg Thieme Verlag Stuttgart New York.
- Campbell, James B.,Sparks, Richard B.,Dedinas, Robert F.
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scheme or table
p. 357 - 360
(2011/03/22)
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- Mo(CO)6-mediated carbamoylation of aryl halides
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A simple method for the synthesis of amides has been developed by molybdenum-mediated carbamoylation of aryl halides. Whereas the conventional palladium-catalyzed three-component coupling reaction requires a large excess of gaseous carbon monoxide, the incorporation of carbon monoxide in this Mo-mediated carbamoylation reaction is so efficient that it requires only a slight excess amount of carbon monoxide in the form of its molybdenum complex, Mo(CO)6. The reaction is applicable for the synthesis of a wide variety of not only secondary and tertiary amides but also primary amides by using aqueous ammonia.
- Ren, Wei,Yamane, Motoki
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experimental part
p. 8410 - 8415
(2011/02/23)
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- Catalytic acylation of amines with aldehydes or aldoximes
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The simple nickel salt NiCl2?6H2O catalyzes the coupling of aldoximes with amines to give secondary or tertiary amide products. The aldoxime can be prepared in situ from the corresponding aldehyde. The use of 18O-labeled oximes has allowed insight into the mechanism of this reaction.
- Allen, C. Liana,Davulcu, Simge,Williams, Jonathan M. J.
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supporting information; experimental part
p. 5096 - 5099
(2011/02/21)
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- Molybdenum-mediated carbonylation of aryl halides with nucleophiles using microwave irradiation
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Figure Presented. A new, efficient, and practical molybdenum-mediated carbonylation of aryl and heteroaryl halides with a variety of nucleophiles is described using microwave irradiation. A range of reactions illustrating the wide scope of this chemistry were carried out and proceeded in good to excellent yields.
- Roberts, Bryan,Liptrot, David,Alcaraz, Lilian,Luker, Tim,Stocks, Michael J.
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supporting information; experimental part
p. 4280 - 4283
(2010/11/04)
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- Carbamoylation of aryl halides by molybdenum or tungsten carbonyl amine complexes
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When aryl halide is treated with molybdenum carbonyl amine complex in the presence of base, carbamoylation proceeds to give amide in good yield. The proposed mechanism involves oxidative addition of aryl halide to molybdenum(0) complex, migratory insertio
- Ren, Wei,Yamane, Motoki
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supporting information; experimental part
p. 3017 - 3020
(2010/07/05)
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- Aryl pyrrolidinones via radical 1,4-aryl migration and 5-endo-trig cyclisation of N-(2-bromoallyl)arylcarboxamides
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Radical reaction of a series of N-(2-bromoallyl)arylcarboxamides led to the production of 4-arylpyrrolidin-2-ones and directly reduced materials in comparable yields. A cascade process, involving sequential 5-exo-trig spirocyclisation, β-scission, and 5-endo-trig cyclisation of the resulting acyl radical, is proposed to explain the pyrrolidinone products.
- Palframan, Matthew J.,Tchabanenko, Kirill,Robertson, Jeremy
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p. 8423 - 8425
(2007/10/03)
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- Reactivity of diacyloxyiodobenzenes toward trivalent phosphorus nucleophiles
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The reaction of diacyloxyiodobenzenes and tetravalent phosphorus nucleophiles was investigated. It was established that both H-phosphonates and secondary phosphine oxides react with diacetoxyiodobenzene in alcohols in the presence of sodium alcoholates yi
- Makowiec, Slawomir,Rachon, Janusz
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p. 352 - 359
(2007/10/03)
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- Enhancing Reductive Cleavage of Aromatic Carboxamides
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(matrix presented) A set of aromatic and especially heteroaromatic N-benzyl carboxamides, derived from naphthalene, pyridine, pyrazine, and quinoline, and the corresponding tert-butyl acylcarbamates have been synthesized and studied by cyclic voltammetry with respect to facilitated reduction. The latter undergo regiospecific cleavage of their C(O)-N bonds under very mild reductive conditions with formation of Boc-protected (benzyl)-amine in most cases in nearly quantitative yields. Examples of preparative cleavage by controlled potential electrolysis, activated aluminum, and NaBH4 are given.
- Ragnarsson, Ulf,Grehn, Leif,Maia, Hernani L. S.,Monteiro, Luis S.
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p. 2021 - 2022
(2007/10/03)
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