Amides production from oximes

The first starting material for building benzodiazepines was prepared inadvertently in a synthesis aimed at the benzodiazoxepine (6-1). The oxime acetamide (6-2) from 2-aminobenzophenone was thus treated with hydrogen chloride in the expectation that the new heterocycle would form by the elimination of water between the oxime and the enol form of the amide. The product mrned out in fact to be the quinazoline A-oxide (6-3), the product from the addition of the nucleophilic oxime nitrogen to the amide carbonyl group. 

Using this pulse sequence to estimate the nature of derivatization of Suwannee River fulvic acid with N-enriched hydroxylamine to leam more about the carbonyl functionality of fulvic acid, Thom et al.(76) obtained signals for the primary products as oximes. Additional signals of secondary products arising from Beckmann rearrangements of the initial oxime derivatives were identified as nitriles, secondary amides and lactams. The bands assigned to hydroxamic acid result from a reaction of esters with NH2OH and are evidence for the presence of esters in the fulvic acid. 

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. ... 

Dehydration reactions using the tertiary phosphine-carbon tetrachloride adduct have appeared quite regularly in the literature again this year. Among those reported have been the dehydrations of oximes to nitriles, carboxylic acids to anhydrides, and the amides (37) to the cumulenes (38). Further reaction of the dehydration product from treatment of the... 

In the present case, only one amide is formed, because benzophenone is a symmetrical ketone. Because the oximes are prepared from ketones, the reaction was often used, before the advent of modern spectroscopic techniques, to determine the structure of the starting ketone. This structure determination was accomplished by the subsequent identification of the acid and amine obtained upon hydrolysis of the amide product of the rearrangement. 

A special experiment shows [343] that N-benzylbenzamide is not a product of oxime rearrangement (upon heating oxime under the same conditions without acetylene, it is nearly completely recovered). Obviously, the key role in the formation of amide from benzyl phenyl ketone belongs to acetylene. 

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. 

A variant on this structure, dioxyline, has much the same activity as the natural product but shows a better therapeutic ratio. Reduction of the oxime (113) from 3,4-dimethoxyphenyl-acetone (112) affords the veratrylamine homolog bearing a methyl group on the amine carbon atom (114). Acylation of this with 4-ethoxy-3-methoxyphenyl acetyl chloride gives the corresponding amide (115). Cyclization by means of phosphorus oxychloride followed by dehydrogenation over palladium yields dioxyline (116). ... 

Piperidine derivatives 161 and 164 could be cyclized to hexahydropyridooxadiazines 162, 165 via a dehydrogenation process by six oxidation equivalents of Hg(n)-EDTA. However, in both reactions, side products were also formed. From 161, piperidone derivative 163 was obtained, whereas starting from the amide 164, pyridopyrimidine 166 was isolated via cyclization by the amide nitrogen instead of oxime oxygen (Scheme 21) <1999ZNB632>. 

The common name caprolactam comes from the original name for the Ce carboxylic acid, caproic acid. Caprolactam is the cyclic amide (lactam) of 6-aminocaproic acid. Its manufacture is from cyclohexanone, made usually from cyclohexane (58%), but also available from phenol (42%). Some of the cyclohexanol in cyclohexanone/cyclohexanol mixtures can be converted to cyclohexanone by a ZnO catalyst at 400°C. Then the cyclohexanone is converted into the oxime with hydroxylamine. The oxime undergoes a very famous acid-catalyzed reaction called the Beckmann rearrangement to give caprolactam. Sulfuric acid at 100-120°C is common but phosphoric acid is also used, since after treatment with ammonia the by-product becomes... 

The unsubstituted 1,2,4-oxadiazole has been prepared from formamidoxime and the mixed anhydride of acetic and formic acid, or formamide <67BSB92>. 5-Unsubstituted 1,2,4-oxadiazoles are formed by heating the condensation products of amide oximes with formic acid <63CI(M)1238>. Alternatively, amidoximes are treated with triethyl orthoformate in the presence or absence of... 

A -(2-Fluoro-2,2-dinitroethyl)hydroxylamine (1) is oxidized by 3-chloroperoxybenzoic acid or bromine to afford oxime 2.218 This compound is unstable and over the course of several weeks at ambient temperature it rearranges quantitatively to amide 3.218 Further oxidation of the oxime 2 with nitric acid or aqueous chromic acid gives a product mixture, from which bis(fluorodinitromethyl)furoxane 4 is isolated.218... 

The key structure of antimicrobial marine natural product, araplysillin-I (28), which was isolated from Psammaplysilla arabica, was synthesized by spiro-annulation of o-phenolic oxime-amide (147) with PIDA [104] (Scheme 18). 

Low-valent metal salts have been used to bring about reductive cleavage of oximes. Corey and Rich-man used chromium(II) acetate to convert O-acetyl ketoximes into imines, which were hydrolyzed to ketones. " Aqueous titanium(III) chloride and vanadium(II) salts also reduce oximes again, the imines are usually hydrolyzed in situ, but some hindered imines, such as compound (37), are isolable." A method of preventing hydrolysis is to carry out the reduction in anhydrous conditions in the presence of an acylating agent. The products of such reactions, when applied to oximes of enolizable ketones, are en-amides. For example, these ketoximes are converted into A/-formylenamines when heated in acetonitrile with anhydrous titanium(III) acetate and acetic formic anhydride cyclohexanone oxime gives the en-amide (38 97% Scheme 22)." This type of reduction has been used by Barton and coworkers to prepare enamides from steroidal oximes. They reported that the reaction could be performed by acetic... 

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