Amide from oximes

Amides from oximes. Microwave irradiation of aldoximes with ZnCl2 (solvent free) accomplishes the transformation into primary amides. 

Carboxylic acid amides from oxime sulfonates CONHR... 

Beckmann rearrangement Carboxylic acid amides from oximes... 

The catalysed synthesis of amides from oximes is usually associated with the Beckmann rearrangement, where an R group migrates to give the for-mamide. In an alternative methodology, the catalysed rearrangement of... 

Scheme 17.39 Ruthenium catalysed qmthesis of primary amides from oximes.

As both are commercially available and easy to handle, it is ideal for such a transformation in the liquid phase. It has proved successful in catalysing the formation of amides from oximes in short reaction times, at relatively low temperatures. ... 

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Dehydration (cf., 6, 648). A reagent (1), prepared in situ from (C6H5),PO and Tf20 in the molar ratio 2 1, effects dehydration, usually at 25°, of amides or oximes to nitriles in >90% yield. It also effects condensation of acids and amines to form amides. The reaction of an aryl carboxylic acid with an o-phenylenediamine promoted by 1 provides 2-arylbenzimidazoles in >80% yield (equation I). If the... 

Wordy Over the past few years, we have encountered numerous examples of water as the perfect solvent. We observed this first in osmium-catalyzed dihydroxylation reactions and also in nucleophilic ring-opening reactions of epoxides. We also observed this in cycloaddition reactions and in most oxime ether, hydrazone, and aromatic heterocycle condensation processes.Finally, we observed it in formation reactions of an amide from a primary amine and an acid chloride using aqueous Schotten-Baumann conditions. ... 

Thieno[4,3,2-/g]benz[l]azocine 187 is produced in high yield (79MI397) from oxime 186 by Beckman rearrangement in PPA. Transformations of amide and thioamide groups of azocines 187 and 188, lead to derivatives 189-192, as shown in Scheme 52. 

Synthesis of heterocycles from amino amide oximes has been described. Recently we have reviewed the synthesis of oximes, oxime 0-ethers and esters, and also the synthesis of heterocycles from oximes covering the literature data published in 1990-1999 . 

Novel a,/ -unsaturated amide derivatives at C(4) of chromones 335 were synthe-sized (equation 124). Oximes 332 and 333 rearranged in the presence of PCI5 into the same amides 335 in high yields. Spiroisoxazolines 334, formed from oxime 332 by acid treatment, also produce 335 under Beckmann rearrangement conditions. 

Other Applications. Hydroxylainine-O-sulfonic acid has many applications in the area of organic synthesis. The acid has found application in the preparation of hydrazines from amines, aliphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. 

The fact that under the same conditions acetophenone oxime does not form amides, but remains intact, also provides evidence against the classical Beckmann rearrangement. The conditions found can be employed for preparing amides from nitriles and aldoximes, especially when the latter contain fragments unstable to acids. In the absence of DMSO, benzaldoxime is dehydrated with alkali only at the boiling point (200°C). 

Evidence that the two reactions are intimately related comes from the formation of the same amide from two different starting materials a tertiary alcohol and an oxime, both based on the... 

Oximes of cyclojjentanone and cyclohexanone undergo the Beckmann rearrangement to cyclic amides from which amino acids may be obtained, e.g., S-aminovaleric acid (71-80%) and e-aminocaproic acid (92%). ... 

Aldoximes are rearranged to amides at 100-150° under the catalytic influence of Raney nickel. The yields of amides from the oximes of acetaldehyde, heptaldehyde, benzaldehyde, and furfural are good (75 96%)> although the reactions are carried out on a small scale only. 

Amines, preparation from amides, 16, 4 from isothiocyanates, 18, 5 from ketones, 17, 76 from oximes, 11. S8 f -Aminobenzaldehyde, 13, 28... 

Regeneration of carbonyl compounds from oximes is accomplished by heating with iodine in MeCN, and a mild workup of the products from reduction of amides with bo-rane involves treatment with iodine. ... 

Chlorination. Amides and carbamates undergo iV-chlorination by NaCl-Oxone. Under the same conditions, oximes afford a-chloro nitroalkanes. - When the chlorine source is absent, regeneration of carbonyl compounds from oximes and hydrazones occurs. ... 

Infrared spectroscopy is used as a monitoring method when the resin is functionalized with linkers that have chemical groups that absorb in the IR spectral region, such as carbonyls, esters, amides, or oximes. IR spectroscopy has also been used to monitor quantitative loading of a resin by comparing the difference in absorbance between two peaks, one from the starting material and the other one from the final product [45]. 

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