Beckmann rearrangement of ketoximes

Sulfamic acid (+H3NS03 ) has been proved to be an efficient and green catalyst for liquid Beckmann rearrangement of ketoxime in anhydrous acetonitrile. Due to its intrinsic zwitterionic property, the use of a base for the neutralization is avoided and wastes can be reduced. 

The Beckmann rearrangement of ketoximes with triphenylphosphine and iV-chloro-succinimide occurs at room temperature almost instantaneously and their corresponding secondary amides are obtained in high yields (equation 83). The triphenylphosphine 271 is activated by the iV-chlorosuccinimide 270 affording the salt 272, which is attacked by the iV-hydroxy group of the oxime 217 forming the intermediate 273. 

Indium trifluoromethanesulfonate was found to be an effective high-yielding catalyst for the facile dehydration of aldoximes to nitriles and Beckmann rearrangement of ketoximes to anilides. ... 

Beckmann rearrangement of ketoximes is achieved efficiently with anhydrous FeCls in the absence of solvent. The rearrangement was selective, producing only one amide isomer in usually good yield. 

Gui et reported the Beckmann rearrangement of ketoximes using a sulfonyl chloride-containing imidazolium-based TSIL to furnish s-caprolactam, which was immiscible in the IL, resulting in easy separation. Similar ILs were... 

It should be noted that amines may be formed by hydrolysis of amides arising from the intramolecular Beckmann rearrangement of ketoximes (p. 1047) this rearrangement is a further example of the migration of a nucleophilic carbon species from a carbon to an electron-deficient nitrogen. 

Such condensation reactions are also promoted by certain trTvalent phosphorus compounds, e.g. triphenyl phosphite (2) or diphenyl ethylphosphonite (3), or to a lesser extent by pFosphonate esters, e.g. diphenyl n-butylphosphonate (3). "Bates reagent," p-oxobi s[tri s(cTi methyl ami no)phosphoni urn] bi s-tetra-f1uoroborate (2) may also be used to activate the carboxyl function towards amide bond formation during peptide synthesis (4) and to bring about the Beckmann rearrangement of ketoximes (F). 

Intramolecular rearrangements provide dramatic evidence to the inadequacy of the theories of directed valence bonds. The Beckmann rearrangement of ketoximes into acid amides, represented by the scheme ... 

Not much attention has been directed to isomerisation and rearrangement reactions in ionic liquids. Beckmann rearrangements of ketoximes have been performed in neat ionic liquids catalysed by phosphorus(V) chlorides and oxides1 301 and Fries rearrangements of phenylbenzoates have been carried out in chloroaluminate ionic liquids with moderate to good selectivity.1 311... 

The Beckmann rearrangement of ketoximes to the corresponding amides (31), the Fischer indole cyclization, isomerization of epoxides to the corresponding aldehydes, ketones, or alcohols, hydration and ammo-nolysis of epoxides, oxygen-sulfur interchange, formation of diaryl-ureas and -thioureas from condensation of aniline and carbonyl sulfide, and olefin carbonylation occur over zeolite catalysts (62). The oxo reaction over rhodium and cobalt containing zeolites recently has been claimed (22). 

Khodaei, M. M., Meybodi, F. A., Rezai, N., Saiehi, P. Soivent free Beckmann rearrangement of ketoximes by anhydrous ferric chloride. Synth. Commun. 2001,31,2047-2050. 

His, S., Meyer, C., Cossy, J., Emeric, G., Greiner, A. Solid phase synthesis of amides by the Beckmann rearrangement of ketoxime carbonates. Tetrahedron Lett. 2003, 44, 8581-8584. 

Lee, J. K., Kim, D.-C., Song, C. E., Lee, S.-g. Thermal behaviors of ionic liquids under microwave irradiation and their application on microwave-assisted catalytic Beckmann rearrangement of ketoximes. Synth. Commun. 2003, 33, 2301-2307. 

Rearrangements. Horning and Stromberg found PPA an excellent solvent-reagent for effecting Beckmann rearrangement of ketoximes°° and aldoximes.° For example, benzophenone oxime (2 g.) when stirred manually with PPA (60 g.) at 130° dissolved in about 10 min., and after dilution of the clear solution with water... 

The bis-phosphonium salt (158) promotes the Lessen rearrangement of phenyl-hydroxamic acids and also brings about the Beckmann rearrangement of ketoximes under mild conditions. The salt (159), (formed from the reaction of 2-hydroxyethyl-triphenylphosphonium chloride with phosgene) has been employed as an amino-... 

Prolonged heating of Bi(OAc)3 wifh amines, N-substituted formamides, and alcohols affords moderate yields of amides, N-acetylformamides, and esters [203]. BiCU mediates the Beckmann rearrangement of ketoximes under microwave irradiation [204[, and Bi(NOj)3- il I,/) mediates fhe guanidylation of N-benzoylfhiour-eas (Scheme 14.100) [205]. 

The Beckmann rearrangement of ketoximes into acid amides, represented by the scheme ... 

Beckmann rearrangement. The antimony(V) salt 1 is an effective catalyst for Beckmann rearrangement of ketoxime trimcthylsilyl ethers to amides or lactams. ... 

Rearrangements. Cyclic ketones utM sdroxyalkyl azides." Regioselectivity is d Beckmann rearrangement of ketoxime o emperature. 

Rearrangements. Cyclic ketones undergo ring expansion on reaction with hydroxyalkyl azides." Regioselectivity is dependent on steric and electronic factors. Beckmann rearrangement of ketoxime carbonates has been observed at room temperature. 

Beckmann rearrangement of ketoximes to synthesize aldehydes. Thus, 4-chlorobenzophenone oxime (LXI) was treated with phosphorus pentachloride and the obtained imidoyl chloride (LXII) was reduced to the corresponding azomethine (LXIII), which on hydrolysis afforded 4-chlorobenz-aldehyde (LXIV) in high yield. 

A complex of pivaloyl chloride and dimethylformamide has been reported to effect Beckmann rearrangement of ketoximes to amides or lactams (Scheme 88). ... 

Peng J, Deng Y (2001) Catalytic Beckmann rearrangement of ketoximes in ionic Liquids. Tetrahedron Lett 42 403 05... 

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