Au/Ag-Cocatalyzed Aldoximes to Amides Rearrangement under Solvent- and Acid-Free Conditions

Ramón, Rubén S.; Bosson, Johann; Díez‐González, Silvia; Marion, Nicolas; Nolan, Steven P.

doi:10.1021/jo902461a

Cited by 142 publications

(47 citation statements)

References 60 publications

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“…This is highlighted in the work reported by Mizuno, [6] Nolan [7] and our own group [8,9] (Scheme 1). Mizuno and co-workers reported a reusable supported rhodium hydroxide catalyst to work in this reaction in aqueous conditions, followed later by Nolan and co-workers reporting a gold/silver co-catalyzed reaction proceeding under solvent-free conditions.…”

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confidence: 59%

Mechanistic Studies into Metal‐Catalyzed Aldoxime to Amide Rearrangements

et al. 2011

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The metal-catalyzed rearrangement of aldoximes into primary amides is a completely atom economical synthetic method for the preparation of one of the most important functional groups in chemistry. There have been several reports of various metals successfully catalyzing this reaction, however, there are conflicting views as to the mechanism involved. Herein we report new experimental evidence to support the mechanism and whether this is universal to all catalysts reported or metal specific. We also describe our further studies into the mechanism of the nickel-catalyzed acylation of amines with aldoximes.Keywords: aldoximes; amides; mechanism; rearrangement The efficient synthesis of amide bonds is of great importance in both research and industrial chemistry due to the prevalence of this group in biologically active molecules, agrochemicals and polymer chemistry.[1] The metal-catalyzed rearrangement of aldoximes into primary amides offers a completely atom economical synthesis of this important chemical moiety. This reaction can also be run from the aldehyde oxidation level with the formation of the aldoxime occurring in situ when mixed with hydroxylamine.The first catalytic conditions for this rearrangement were reported by Chang and co-workers in 2003. [2] They found that Wilkinsons complex (at a catalyst loading of 5 mol%) efficiently catalyzed the conversion of a range of aldoximes into their corresponding primary amides at a temperature of 150 8C. Following this initial publication, reports of iridium, [3] ruthenium [4] and palladium [5] catalysts performing the rearrangement appeared in the literature detailing procedures at lower temperatures.Research efforts have more recently been focussed towards finding lower cost metal catalysts and procedures that can be run in the absence of undesirable organic solvents. This is highlighted in the work reported by Mizuno, [6] Nolan [7] and our own group [8,9] (Scheme 1). Mizuno and co-workers reported a reusable supported rhodium hydroxide catalyst to work in this reaction in aqueous conditions, followed later by Nolan and co-workers reporting a gold/silver co-catalyzed reaction proceeding under solvent-free conditions. We have shown that relatively inexpensive copper, zinc and indium salts are as effective as the precious transition metals at catalyzing aldoxime rearrangements. It has been proposed that the mechanism for this metal-catalyzed rearrangement proceeds via a discrete nitrile intermediate which is formed through dehydration of a coordinated oxime species. This is supported by the frequent detection of a small quantity of nitrile by-product on analysis of the crude reaction Scheme 1. Recently reported conditions for aldoxime rearrangements into primary amides.

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confidence: 59%

Mechanistic Studies into Metal‐Catalyzed Aldoxime to Amide Rearrangements

et al. 2011

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“…As it is reported by several authors [6][7][8][9][10][11], benzaldoxime transforms into benzonitrile (nitrile), benzaldehyde (aldehyde) and benzamide, of which benzamide is the main (desired) product. Indeed, the transformation of benzaldoxime into benzamide is a two-step process, wherein, the selective dehydration of benzaldoxime leads to benzonitrile, which on hydrolysis converts into benzamide.…”

Section: Catalytic Activitymentioning

confidence: 76%

“…In a recent report, solvent-free and acid-free Au/Ag co-catalysts are disclosed for the effective conversion of aldoximes to primary amides [9]. However, these Au/Ag co-catalysts are homogeneous in nature.…”

Section: Introductionmentioning

confidence: 99%

Cu/SBA-15 is an Efficient Solvent-Free and Acid-Free Catalyst for the Rearrangement of Benzaldoxime into Benzamide

et al. 2011

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Cu/SBA-15 catalysts with various Cu loadings in the range of 5-20 wt% were prepared by an impregnation method and characterized by N 2 adsorption, X-ray diffraction, temperature programmed reduction and X-Ray photoelectron spectroscopic techniques. Cu/SBA-15 catalysts are found to be highly active and selective for the Beckmann rearrangement of benzaldoxime into benzamide under solvent-free and acid-free conditions.

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“…To 28 a solution of 0.8 mmol of 19a,b in 20 mL of hot ethanol, 15 mg of 10% palladium on activated charcoal as a catalyst was added. The mixture was left under hydrogenation in a Parr apparatus at 40 psi for 24 h to obtain 20a,b after crystallization.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, antiproliferative activity and possible mechanism of action of novel 2-acetamidobenzamides bearing the 2-phenoxy functionality

Raffa¹,

Maggio²,

Plescia³

et al. 2015

Bioorganic & Medicinal Chemistry

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Several new 2-(2-phenoxyacetamido)benzamides 17a–v, 21 and 22 were synthesized by stirring in pyridine the acid chlorides 16a–e and the appropriate5-R-4-R1-2-aminobenzamide 15a–e and initially evaluated in vitro for antiproliferative activity against the K562 (human chronic myelogenous leukemia) cell line. Some of synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell line panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). The most active compounds caused an arrest of K562 cells in the G0–G1 phase of cell cycle and induction of apoptosis, which was mediated by caspase activation.

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Au/Ag-Cocatalyzed Aldoximes to Amides Rearrangement under Solvent- and Acid-Free Conditions

Abstract: The gold/silver-cocatalyzed conversion of aldoximes into primary amides is reported. The reaction, which proceeds under neat and acid-free conditions, allows for the conversion of a range of aldoximes, and is a rare example of cooperative catalysis involving well-defined gold species.

Cited by 142 publications

References 60 publications

Mechanistic Studies into Metal‐Catalyzed Aldoxime to Amide Rearrangements

Mechanistic Studies into Metal‐Catalyzed Aldoxime to Amide Rearrangements

Cu/SBA-15 is an Efficient Solvent-Free and Acid-Free Catalyst for the Rearrangement of Benzaldoxime into Benzamide

Synthesis, antiproliferative activity and possible mechanism of action of novel 2-acetamidobenzamides bearing the 2-phenoxy functionality

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