Beckmann Rearrangement Of Oxime Research Articles

Recyclable Polymer-Supported Terpyridine–Palladium Complex for the Tandem Aminocarbonylation of Aryl Iodides to Primary Amides in Water Using NaN3 as Ammonia Equivalent

Primary aromatic amides are valuable compounds, which are generally prepared via Beckmann rearrangement of oximes and the hydration of nitriles in organic solvents. We investigated the environmentally friendly catalytic aminocarbonylation in water. Thus, a novel heterogeneous transition-metal catalyst, a polymer-supported terpyridine–palladium(II) complex, was prepared and found to promote azidocarbonylation of aryl iodides with NaN3 and to reduce the generated benzoyl azides in water under CO gas to yield primary aryl amides with high to excellent yield in a one-pot reaction. The catalyst was recovered and reused several times with no loss of catalytic activity.

Low Environmental Load Process for the Beckmann Rearrangement of Cycloalkanone Oximes by Brønsted Acid Catalyst with Cobalt Salts

Beckmann rearrangements of oximes to lactams often require harsh conditions and/or the use of large amounts of acid catalyst. To reduce the amount of Bronsted acid required, and to avoid the formation of a large amount of undesirable byproducts under mild reaction conditions, a low environmental load process was developed. Beckmann rearrangements of cyclohexanone oxime and cyclooctanone oxime were achieved using a combination of a Bronsted acid and cobalt tetra-fluoroborate hexahydrate. Various Bronsted acid catalysts (10 - 20 mol%) were used to obtain the corresponding lactams in high yields at 80℃.

Facile Synthesis of Thioamides via P2S5‐Mediated Beckmann Rearrangement of Oximes

AbstractA facile and efficient approach to the synthesis of secondary thioamides from ketoximes via Beckmann rearrangement has been established, using phosphorus pentasulfide as a dehydrating and thiating agent. It is also efficient for the preparation of primary thiobenzamide from benzaldoxime. This approach features simple‐operation, easy‐control and good to excellent yields.

Acid hydrolysis of amides obtained by Beckmann rearrangement of methyl ketones oximes of unsaturated γ-lactone, aromatic, and alicyclic series

Beckmann rearrangement was performed of oximes of substituted 3-acetyl-4-methyl-5,5-dimethyl(pentamethylene)-2-oxo-2,5-dihydrofuranes in the presence of boron trifluoride etherate. Aiming at establishing the spatial arrangement of the oximes the hydrolysis was carried out of acid amides obtained by Beckmann rearrangement of oximes of methyl ketones belonging to unsaturated γ-lactone series and also to aromatic and alicyclic series. The hydrolysis with 20% sulfuric acid led to the formation of the corresponding acid and amine, and the hydrolysis with acetic and hydrochloric acids resulted in retrobeckmann rearrangement giving the initial oximes.

ChemInform Abstract: Beckmann Rearrangement of Oximes Catalyzed with Tetrabutylammonium Perrhenate and Trifluoromethanesulfonic Acid.

The Beckmann rearrangement of oximes is catalyzed by a combined use of tetrabutylammonium perrhenate (Bu4NReO4) and trifluoromethanesulfonic acid in nitromethane under azeotropic conditions, giving amides in high yield. By employing this catalytic system, amides can be prepared directly from ketones and hydroxylamine hydrochloride.

One‐Pot Synthesis of Lactams from Cycloalkanes and tert‐Butyl Nitrite by Using N‐Hydroxyphthalimide as Key Catalyst

Lactams were successfully synthesized in the one-pot reaction of cycloalkanes and tBuONO in the presence of N-hydroxyphthalimide as a key catalyst. Cyclododecane and cyclohexane were treated with tBuONO followed by triethylamine and then cyanuric chloride in a one-pot manner to give laurolactam and epsilon-caprolactam, respectively, in good yields. The Beckmann rearrangement of oximes by cyanuric chloride was found to be accelerated by the use of 1,1,1,3,3,3-hexafluoro-2-propanol as solvent. The method provides the first successful environmentally benign direct synthetic route to lactams from cycloalkanes without the formation of any salt.

Facile One-pot Syntheses of Amidines and Enamines from Oximes via Beckmann Rearrangement Using Trifluoromethansulfonic Anhydride

Abstract Facile one-pot syntheses of amidines and enamines were achieved by trapping carbocation intermediates that were formed by Beckmann rearrangement of oximes with amines and carbon nucleophiles, respectively, under mild conditions.

Structure of the Product of the Beckmann Rearrangement, 2-Methyl-4,5,6,7-Tetrahydrobenzothiazol-7-one Oxime

Buu-Hoi et al. [2] described the Beckmann rearrangement of oxime III, occurring on heating in polyphosphoric acid (PPA), and identified the product as 2-methyl-4,5-dihydro-8H-thiazolo[5,4-b]azepin-7(6H)one IV. We performed the Beckmann rearrangement of oxime III under the same conditions but obtained a product whose physicochemical properties fully coincide with those of compound II obtained by the Schmidt reaction. Thus, the Beckmann rearrangement of oxime III yields thiazoloazepine II and not IV. The H NMR spectra were taken on a Bruker WM250 spectrometer (250 MHz, internal reference TMS). The mass spectra were taken with an MKh-1321 mass spectrometer using the direct inlet system (ionizing electron energy 70 eV).

Rhodium-catalyzed Beckmann rearrangement.

[figure: see text] Beckmann rearrangement of oxime is catalyzed by [RhCl(cod)]2, trifluoromethanesulfonic acid, and tris(p-tolyl)phosphine in refluxing dichloroethane, giving the corresponding amide in good yield. Product/acid ratios of 10:20 can be attained in the reaction of benzophenone oximes.

Indium-Mediated Facile Dehydration and Beckmann Rearrangement of Oximes

Abstract Indium chloride has been developed as an efficient reagent for the conversion of aldoximes to nitriles and the Beckmann rearrangement of ketoximes to anilides.

Microwave Induced Bismuth Trichloride Catalysed Beckmann Rearrangement of Oximes

A new and efficient method for the rearrangement of oximes 1 has been achieved by a simple reaction of a ketoximes with bismuth trichloride under microwave irradiation in the solid state.

Active sites for the liquid-phase beckmann rearrangement of cyclohexanone, acetophenone and cyclododecanone oximes, catalyzed by beta zeolites

The Beckmann rearrangement of oximes with different molecular sizes, i.e. cyclohexanone, cyclododecanone, and acetophenone oximes, has been studied in liquid phase at 130°C over a series of four Beta zeolites differing in the presence or absence of framework Al and internal silanol groups. When the zeolite does not contain framework Al and internal silanols, no appreciable conversion was observed. The catalyst having internal silanol groups but no framework Al exhibits oxime conversion, but the selectivity to the corresponding amide is low in some cases. In the Beta zeolite without silanol groups but containing framework Al, conversion and selectivity were found to be very high. This superior performance of Bronsted acid sites, compared to silanol groups, shows that the results reported for the vapor phase reaction cannot be extrapolated when the reaction is performed in liquid phase. Finally, as could be anticipated according to the dimensions of the micropores, it is shown that H-Beta zeolites exhibit a much better catalytic performance than H-ZSM-5 zeolite for larger sized oximes.

A Facile Beckmann Rearrangement of Oximes with AlCl3 in the Solid State

A facile and efficient synthetic procedure, for Beckmann rearrangement of oximes with AlCl3 in the absence of solvent is developed. We have been able to convert cyclohexanone oxime to ϵ-caprolactam in a quantitative yield.

Beckmann Rearrangement of Oximes Derived from Ring and Side Chain Substituted 3-Phosphonomethylcyclohexenones†

Beckmann rearrangement of the oximes of 3-phosphonoalkylcyclohexenones affords lactams resulting from the regioselective migration of the 6-CH2 ring carbon atom.

Possible reaction mechanisms of hydrogen cyanide formation from oxime blocked isocyanates and related organic compounds during total cyanide analysis

Frequent reports by paint manufactures of hydrogen cyanide detection in waste contaminated with oxime blocked isocyanates lead to an investigation of possible hydrogen cyanide generating reaction pathways. GC‐MS is empolyed to analyze traces of byproducts of the total cyanide analysis. A Beckmann Rearrangement of oxime blocked isocyanates has been detected. The formation of α‐ketocyanides and their hydrolysis to free hydrogen cyanide is reported as the key compound that leads to hydrogen cyanide generation. Hydrogen cyanide yields from the reaction of NOx or hydroxylamine with ketones, alcohols, amines, peptides, EDTA, ascorbic acid and cyanides. The presence of an organic phase improves hydrogen cyanide yields. A sample pretreatment for oxime blocked isocyanate samples is described.

A Facile dehydration and beckmann rearrangement of oximes with aluminium iodide

Aluminium iodide has been developed as an efficient reagent for the conversion of aldoxims to nitriles and the Beckmann rearrangement of ketoximes to anilides.

Synthesis of 3β-Acetoxy-7a-aza-B-homo-22a-spirost-5(6)-en-7-one

Chromic acid oxidation of diosgenin acetate yielded 7-ketodiosgeninacetate. Oximation of the ketone followed by Beckmann rearrangement of oxime afforded the title compound.

Indoles. V. Syntheses and reactions of cycloalkanon[c,d]indole derivatives.

A convenient synthetic method for cycloalkanon [c, d] indoles (1 and 8) and some of their reactions were examined. The Friedel-Crafts reaction of 1-acetylindol-3-ylpropionic acids (4b and 4c) gave cyclopent [b] indoles (5b and 5c). This result indicates the general tendency of cyclization of 1-acetylindol-3-ylalkanoic acid, different from only one example reported previously by Szmuszkovicz, who prepared benz [c, d] indole derivative (3) from 1-acetylindol-3-ylsuccinic anhydride (2). The Friedel-Crafts reaction of 2-ethoxycarbonylindol-3-ylalkanoic acids (7b, 7c, and 7b), which were obtained in a good yield from easily available starting materials, gave cycloalkanon [c, d] indoles (8a, 8c, and 8e) in 24, 66, and 73% yield, respectively. Saponification and decarboxylation of 8a and 8e gave Uhle's ketone (1a) and a new ketone (1b), respectively. The Beckmann rearrangement of oximes (9a and 9b) with polyphosphoric acid gave lactams (10a and 10b) resulting from aryl migration. This is different from Bowman's example, in which lactams (11a and 11b) resulting from alkyl migration are obtained by the Beckmann rearrangement of oximes (9c and 9b) with thionyl chloride. Saponification and decarboxylation of 10a and 10b gave azepino [c, d] indolone (10c) and azocino-[c, d] indolone (10d) in 50 and 55% yield, respectively. 5-(3-Ethoxycarbonyl-5-oxo-2-pyrrolin-1-yl)-6 (1H)-oxo-3, 4, 5, 6-tetrahydrocyclohept-[c, d] indole (15b) was obtained from 1b by Stoll's method and its structure was elucidated from its nuclear magnetic resonance and mass spectra.

Alkylation, acylation, and Beckmann rearrangement of oximes in the presence of an oxidation–reduction system

The system triphenylphosphine–diethyl azodiformate (TPP–DAF) can interact with oximes in the presence of either carboxylic acids or alcohols. Reactions of benzophenone oxime with a variety of aromatic carboxylic acids lead to O-acyl derivatives which undergo spontaneous Beckmann rearrangement. This modification of the Beckmann rearrangement takes place under very mild (0 °C), aprotic (tetrahydrofuran), and weakly acidic conditions, affording NN-diacyl aromatic amines as final products. The reaction of benzophenone oxime with alcohols in the presence of TPP–DAF gives O-alkyl ethers of the oxime. A mechanism is proposed.

Functionally substituted organotin compounds : V. Beckmann rearrangement of oximes containing organotin substituents

The structures of the oximes formed from (4-oxopentyl)triphenyltin and (4-oxopentyl)diphenyltin chloride have been determined using IR, PMR and Mössbauer spectroscopy. Beckmann rearrangement of (4-oximinopentyl)diphenyltin chloride with phosphorus pentachloride gave the amide resulting from exchange of syn groups. Treatment of the second oxime with phosphorus pentachloride caused other reactions but the O-tosyl derivative was rearranged under mild conditions to give a mixture of amides.