A-chloramine

Thionyl chloride/pyridine treatment of oximes (557) is believed not to proceed via an intermediate like (558) in the generation of 1,2-benzisoxazoles, but by a chloramine intermediate (Scheme 170). A similar reaction of an A-phenylhydroxamic acid generated a benzisoxazolinone via a proposed chloramine intermediate (Scheme 170) (77AJC1847). 

The carbonyl group of the pyrrolizinone lc has been reduced with NaBH4 to give alcohol 171 <2004JME1448>. Condensation of lc with hydroxylamine in pyridine gave the oxime 172 in 95% yield. The latter was substituted by a chloramine chain to form the corresponding oxime ether 173 (Scheme 22) <2004JME1448>. 

Iodobeads (Thermo Fisher) is an immobilized preparation of a chloramine-T analog, consisting of nonporous, polystyrene beads of diameter 1/8" that have been derivatized to contain N-chlorobenzenesulfonamide groups (as the sodium salt) (refer to US patents 4,448,764 and 4,436,718). During the manufacturing process, the hydrophobic nature of the polystyrene is changed to a rather hydrophilic surface due to the chlorosulfonamide modifications. The surface... 

The results of kinetic studies on the reaction between iodide and A-chloro compounds support a mechanism in which the rate-determining transfer of C1+ from the A-chloramine to iodide gives an ICl intermediate which rapidly reacts with excess iodide to give triiodide ions. ... 

Alkenes can be aziridinated using a variety of nitrogen sources. Among the recently reported systems are Chloramine T (iV-chloro-A -sodio-p-toluenesulfonamide) with pyridinium hydrobromide perbromide catalyst (c.g., 119 120) <99OL705>, the A -chloramine salt of t-... 

Thus hydrocliloric acid reacts in the presence of nitric acid to yield chlorine acetate (a)—a compound with cationic chlorine. The latter in turn forms a chloramine (b) which is nitrated to a nitramine (c). 

IfXis nitrogen then a direct method of animation results. The required reagent is a chloramine or the rather safer O-hydroxylaminesulfonic acid the leaving group is chloride or sulfonate. The overall... 

The exceptions are chloramines of valine, leucine, and isoleucine, which form semistable chloramines that remain in the reaction medium for several hours (Z4). The mechanism of aldehyde formation from the intermediary amino acid a-chloramines produced either by HOC1 treatment or by the MP0-H202-C1- system was recently verified with use of NMR spectra. The study made possible the identification of short-lived products of the reaction, and confirmed the role of the unstable monochloramine of the a-amino group as the intermediate (H12). 

An early version was the Hofmann-Loffler-Freytag reaction (Scheme 1). Irradiation of a chloramine in acid leads to formation of the aminium radical, which can abstract a hydrogen to generate a caibon radical. Then the resulting carbon radical abstracts chlorine from another protonated chloramine, producing a chlorinated carbon and regenerating the chain-carrying radical. On treatment with base, the product... 

CHLORAMINE SKY BLUE A CHLORAMINE SKY BLUE 4B CHROME LEATHER PURE BLUE C.L 24400... 

Establishing a chloramine residual involves a period of mixing the chlorine and ammonia with the water, followed by a short holding time to allow the reactions to take place. Usually, chloramine-forming reactions are at least 99% complete within a few minutes. 

A few intramolecular addition reactions involving a chloramine and a ketenimine have also been reported, but the yields were low. 

This cross-link can, however, be severed by acid hydrolysis with the formation of an imino group capable of yielding a chloramine. 

Carr, A.C., Hawkins, C.L., Thomas, S.R., Stocker, R., and Frei, B. (2001). Relative reactivities of A-chloramines and hypochlorous acid with human plasma constituents. Free Radic Biol Med 30,526-36. 

The two most commonly deployed UK antigas ointments during World War II (A/G No. 5 and No. 6) contained a chloramine termed antiverm (AV 2,4-dichlorophenyl benzoyl chloroimide) to chemically neutralise vesicant agents. Both were efficacious decontaminants and prophylactics against vesicants, although A/G No. 6 was the preferred formulation for tropical conditions. 

There are comparatively very few kinetic studies of beta-eliminations giving imines or nitriles. Nitriles can be prepared by the acid-catalysed dehydration of amides or aldoximes or by the base-catalysed elimination from aldochlor-imines or esters of aldoximes. Imines often result in the attempted preparation of A-chloramines, dehalogenation occurring in the weakly alkaline hypochlorite solution which is used as the chlorinating reagent. 

Replacement of the boron atom for a nitrogen atom is possible with a suitable aminating agent. Treatment of a trialkylborane with a chloramine, prepared in situ by oxidation of ammonia or an amine with sodium hypochlorite, provides a method to form a carbon-nitrogen bond (5.26). The transformation of an alkene to an amine by overall addition of ammonia is much less straightforward than hydration and this methodology, although used less frequently than oxidation with peroxide, provides a solution to this problem. 

---