Haloamides, and

Tetramethylguanidinium azide, an azide salt that is readily soluble in halogenated solvents, is a useful source of azide ions in the preparation of azides from reactive halides such as a-haloketones, a-haloamides, and glycosyl halides.74... 

Saturated /V-haloamides and /V-nitrosamides, upon UV photolysis, undergo remote functionalizations 8 to nitrogen on the alkyl or, less effec-... 

A-Haloamides and imides are a most versatile group of halogenating reagents. They are normally prepared in an aqueous solution by reaction of the parent amide/imide with the corresponding hypohalite. An improved method for the synthesis of A-bromo amides/imides has recently been published, in which the parent compounds are oxy-brominated in aqueous solution by a mixture of HBr/NaBr03 or NaBr/NaBr03/H2S04 (equation 95)700. 

Reduction of substituted 2-haloamides 6 appears to occur through an intermediate aziridinone 7 (equation 4). 2-Haloamide anions are formed by electro reduction of the corresponding NH-protic 2-haloamides and self-protonated. Such anions are labile species whose decay, in the case of 2-bromoamide anions, competes with their electroreduction in... 

Oxidations.1 The reagent compares favorably with N-haloamides and chromic acid for oxidation of secondary alcohols. Cyclohexanol is oxidized to cyclohexanone in 90-95% yield at room temperature. Less easily oxidized alcohols may require higher temperatures to initiate the free-radical reaction. The oxidation may become too vigorous if cooling is insufficient or if run on a large scale. 

Oximes play an important role as protecting groups due to their hydrolytic stability. Their frequent use has provided incratives far the develqnnent of newo deoximation reagents such as pyridinium chlorochromate, Raney nickel, triethylammonium chlorochromate, pyridinium chlorochromate-H202, nitrogen tetroxide, trimethylsilyl chlorochromate, H2O2 over titanium silicalite-1, Dowex-SO, dimethyl dioxirane, zirconium sulfophenyl phosphonate, AT-haloamides, and bismuth dil( ide (22). 

Benzylic and allylic chlorides and bromides, acid chlorides and bromides, and a-haloketones, a-haloesters, a-haloamides, and a-halonitriles also give a positive test at room temperature. 

Carbonylation Reactions. A three-component palladium-catalyzed amidocarbonylation reaction provides IV-acylamino acids from aromatic and aliphatic aldehydes or acetals with amides under elevated CO pressure (60 bar) in the presence of PdBr2, PPhs, LiBr, an acid additive (typically H2SO4), and iV-methyl-2-pyrrolidone. Mechanistically, the palladium-catalyzed amidocarbonylation reaction is proposed to proceed through the in situ formation of an a-haloamide and Pd(0) species, which can undergo oxidative addition, followed by CO insertion, and lastly hydrolysis of the acyl palladium complex to afford the product and regenerate the catalyst (eq 45). 

The general theory behind the process is that the hypohalite will convert the amide to a haloamide. This then spontaneously changes to the isocyanate when heated and decomposes to the amine from the water present. In effect, all that happens is that a Carbonyl (CO) group is stripped off the starting amide to yield the corresponding amine. Yields pre- purification are around 80%, post-purification average around 65%. Certain uses of the result-... 

This last solution should be prepared slowly as it is quite exothermic. Set all three aside in a freezer. Now prepare the mixing apparatus which will be a stainless steel "mixing bowl" suspended In the ice/salt bath made earlier. We use a stainless steel bowl here so that heat transfer will be maximal, while preventing any corrosive interaction. A glass bowl will not be sufficient for larger scale preparations as it will not conduct heat fast enough to prevent the reactants from going over IOC (at which point the Haloamide will decompose and you ll have to start over). Take the Sodium Hydroxide solution out of the freezer once it is cool, but not cold. 

Preparation from Nitrene Intermediates. A convenient, small-scale method for the conversion of carboxyhc acid derivatives into isocyanates involves electron sextet rearrangements, such as the ones described by Hofmann and Curtius (12). For example, treatment of ben2amide [55-21-0] with halogens leads to an A/-haloamide (2) which, in the presence of base, forms a nitrene intermediate (3). The nitrene intermediate undergoes rapid rearrangement to yield an isocyanate. Ureas can also be formed in the process if water is present (18,19). 

A iD-Corticoids have been important intermediates since it was shown ° that substitution at C-9 enhances anti-inflammatory activity. These olefins are usually obtained from 11a- or 11)5-alcohols, and consequently several refined methods have been devised for effecting this dehydration. It is desirable that such methods be compatible with the presence of A" -3-ketone and 17-hydroxy functions. The first direct procedure for which high yields were claimed was described in a patent issued to Upjohn. According to this method, the alcohol (11a or )5) is treated first with A-bromoacetamide in pyridine, then with sulfur dioxide. Recently it has been claimed " that the A-haloamide/sulfur dioxide method gives results superior to other methods, although the methanesulfonyl chloride/sulfur dioxide procedure (see below) apparently was not compared (see also ref. 94). 

Enol ethers are readily attacked in buffered medium by electrophilic reagents such as halogens, A -haloamides, perchloryl fluoride and organic peracids to give a-substituted ketones. Similarly, electrophilic attack on... 

In this paper Speziale and Smith 109) described experiments which led them to modify the mechanism proposed earlier 108) for the reaction of trivalent phosphorus compounds with haloamides. The first step is considered to be attack of the trivalent phosphorus compound on a chlorine atom of the halo amide (132) to produce a resonance-stabilized enolate ion (133). This is reasonable since under conditions where the trichloroamide... 

In an alternate approach to the preparation of compounds containing the additional ring, haloamide, 41 (obtained from the aminobenzophenone and bromoacetylbromide) is alkylated with etha-nolamine to afford 42. Treatment of the amino alcohol in acetic acid affords the carbonyl addition product, 43, at the same time... 

In the second, >100 DBFs were identified in indoor chlorinated and brominated pools, including many nitrogenous DBFs (haloamides, halonitriles, haloanilines, haloamines, haloanisoles, and halonitro-compounds), likely due to the nitrogen-containing precursors from swimmers (urine, sweat, etc.) [143]. Trichloramine and THMs were also measured in the pool air [143]. Nitrosamines have been measured in chlorinated pools and hot tubs, up to a maximum of429 ng/L... 

This chapter will address the synthesis, theoretical and physical properties and reactivity of a number of different classes of anomeric hydroxamic esters. Principal categories include A-aUtoxy-A-haloamides (XNO systems), A-acyloxy-A-alkoxyamides and A,A-dialkoxyamides (ONO systems), A-alkoxy-Al-aminoamides (ONN systems) and N-... 

Anchimeric assistance by the aUcoxyl oxygen lone pair promotes heterolytic S v 1 and reactions at nitrogen as well as homolysis of the N—Cl bond. A-Haloamides are also amidyl radical sources" but their heterolytic reactivity is known to involve positive, rather than negative, halogen ... 

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