Nitrosyl chloride, effect

Equations 1-10 illustrate some mild methods that can be used to cleave amides. Equations 1 and 2 indicate the conditions that were used by Woodward and Eschenmoser, respectively, in their synthesis of vitamin B12. Butyl nitrite, nitrosyl chloride, and nitrosonium tetrafluoroborate (NO BF4 ) have also been used to cleave amides. Since only tertiary amides are cleaved by potassium -butoxide (eq. 3), this method can be used to effect selective cleavage of tertiary amides in the presence of primary or secondary amides.(Esters, however, are cleaved by similar conditions.) Photolytic cleavage of nitro amides (eq. 4) is discussed in a review. 

Walden concluded that potassium hydrate and phosphorus penta-chloride acted optically normally, i.e. without alteration of the configuration, but that silver oxide, and therefore also nitrous acid and nitrosyl chloride, acted optically abnormally, but as to which of these reactions was really the normal one he was not able to decide. The conclusion was remarkable, since the action of silver oxide takes place in aqueous. solutions at a low temperature and the effect of potash in producing racemisation is well known. Still more curious is the supposition that nitrous acid and nitrosyl chloride act optically abnormally. 

Nitrosyl bromide also added to imines but the yields of a-acetates after the addition of silver acetate were not better than these obtained by the addition of nitrosyl chloride. Because of their high reactivity, it was not possible to isolate a-bromodialkylnitrosamines in either case. Presumably, steric effects may also operate. 

Although it is evident that the reaction is almost entirely homogeneous, Stoddart403,404 presented evidence that the rate of reaction is influenced by the history of the reaction vessel it diminishes from experiment to experiment when starting with a new vessel it also diminishes with time during the course of a single experiment. However, the termolecular rate constant does not depend on the surface-to-volume ratio. He concluded that these effects are due to activated adsorption or chemisorption of nitrosyl chloride on the adsorbed moisture of the... 

Deoximation.1 This reaction can be effected with this combination of reagents and a phase-transfer catalyst at room temperature in yields generally >90%. The actual reagent is believed to be nitrosyl chloride, NOC1. 

Johnston and Leighton studied the effect of adding N2O5 to a mixture of ozone and nitrosyl chloride in the gas phase. The stoichiometry of the reaction is, in fact,... 

Electron-deficient alkenes (e.g., NCHC=C(COOMe)2) can be aziridinated with 0-(aryl-sulfonyl)hydroxylamines <9lCOS(7)469>. The reaction is believed to involve a Michael addition followed by cyclization with expulsion of a sulfonate anion. Less electrophilic alkenes react in lower yield but with high stereoselectivity (Equation (2)). The chiral catalyst prepared from an optically active bisoxazoline and Cu(I)triflate is effective in promoting the enantioselective aziridination of alkenes <93JA5328>. The addition of nitrosyl chloride to alkenes, which are especially susceptible to... 

Solvent effects Birch reduction. 1,2-Dimethoxyethane (Glyme) and Dimethyl ether (see Naphthalene-Sodium), Dimethylformamide. Dimethyl sulfone. Dimethyl sulfoxide. Diphenyl sulfoxide. Ethylene glycol. N-EthylmorphoUne. Hexamethylphosphoric triamide. Methylal. Methylene chloride. Methyl ethyl ketone. N-Methyl-2-pyrrolidone. Nitrometbane. Nitrosyl chloride. Phenetole. Tetrahydrofurane. Tetramethylene sulfone. Tetramethylene sulfoxide. Triethanolamine. Triethyl phosphate. Trifluoroacetic acid,... 

Mononitrosation of cyclohexanone can be effected by reaction with slightly more than 1 eq. of nitrosyl chloride in liquid sulfur dioxide in the presence of an alcohol and 1 eq. of hydrochloric acid at about -10 (equation 1). The product... 

The kinetics of addition of nitrosyl chloride to a number of olefins have been examined. In chloroform, methyl and phenyl substituents enhance the rate while electron-withdrawing groups (e.g. chlorine) retard it. Such be-haviour would be consistent with electrophilic attack by the dipole NO-CP. The effect of changes in the solvent was not simple, although more polar solvents (nitrobenzene, chloroform) speeded the reaction (compared with toluene or carbon tetrachloride). Methanol appeared to be a remarkably poor reaction medium, perhaps due to interaction with the reactant the low reactivity of nitrosyl chloride in diethyl ether was attributed to strong bonding between the solvent and the incipient NO cation. 

Aqua regia is the most known and used mixture, and is a good oxidant due to the formation of nitrosyl chloride (NOCl). Upon heating, dissociation of NOCl into CI2 occurs, which continues attacking the samples and produces an effective digestion in closed containers. This effect is the cause of the oxidation of many materials, which occurs more effectively than with HNO3 or HCl alone (8 ml to 316 W 180°C and 7 atm in 16 min). 

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