Nitrosyl chloride, formation

A photochemical partial synthesis of aldosterone (19) made the hormone available on an industrial scale for the first time (114). Corticosterone acetate (51 acetate) is treated with nitrosyl chloride in pyridine at 20°C to yield the 11-nitrite (115). Irradiation of (115) leads to rearrangement with formation of the C g-oxime (116). Removal of the oxime residue with nitrous acid furnishes aldosterone (19) in excellent yield. 

No accurate rate measurements have yet been carried out, but qualitative experiments showed that the exchange was acid-catalysed so that it is likely that the protonated form of the nitrosamine (LIII) acts itself as a nitrosating agent. This would account for all the earlier cross-nitrosations that have been observed without necessitating the prior formation of nitrous acid, nitrosyl chloride or any other carrier of NO+. 

For nitrosyl chloride (Entry 8) and nitrosyl formate (Entry 9), the electrophile is the nitrosonium ion NO+. The initially formed nitroso compounds can dimerize or isomerize to the more stable oximes. 

Ketimines were successfully nitrosated by treatment with nitrosyl chloride in cold carbon tetrachloride resulting in the formation of N-nitrosoimines (Scheme 3.25) [201],... 

J Honzl, J Rudinger. Amino acids and peptides. XXXIII. Nitrosyl chloride and butyl nitrite as reagents in peptide synthesis by the azide method suppression of amide formation. Coll Czech Chem Commun 26, 2333, 1961. 

Secondary amines are converted into the corresponding A-nitrosoamines in high yield (-90%) by sodium nitrite and ALchloro- or A-bromosuccinimide under liquiddiquid two-phase conditions in the presence of lipophilic quaternary ammonium salts [41]. There is evidence that nitrosyl chloride is initially formed, which reacts with the nitrite ion to generate N204. Hydrophilic ammonium salts do not promote the formation of N204 and the final products are the A-haloamines. 

Schroeder, W. H., and P. Urone, Formation of Nitrosyl Chloride from Salt Particles in Air, Enriron. Sci. Technol., 8, 756-758 (1974). 

The conditions under which HC1 formed in acidified sodium chloride droplets would be expected to enter the gas phase have been treated by Clegg and Brimble-combe (1990). Cadle and co-workers (Robbins et al., 1959 Cadle and Robbins, 1960) observed that NaCl aerosols in the presence of 0.1-100 ppm NOz at relative humidities of 50-100% lost chloride ion from the particles. They ascribed this to the formation of nitric acid from NOz, followed by reaction (1). Schroeder and Urone (1974) subsequently suggested that NOz could react directly with NaCl to produce gaseous nitrosyl chloride, C1NO, which they observed using infrared spectroscopy stoichiometrically, this is represented as... 

Aziridines can undergo loss of a nitrogen atom in a number of ways and this process is frequently stereospecific in terms of the alkene formed. For example, the reaction of aziridines, e.g. (268), with nitrosating agents such as nitrosyl chloride or methyl nitrite results in the formation of alkenes wit.h greater than 99% stereoselective deamination (64JOC1316). Such transformations proceed via N- nitrosoaziridine intermediates which are isolable at temperatures below -20 °C, but which decompose to the observed products at higher temperatures. 

Nitrosyl chloride is a sufficiently powerful reagent to permit the formation of jV-nitroso derivatives of amides from secondary carbinamines. In this regard the reagent differs markedly from those used in the first three methods mentioned above. The use of the reagent is quite general and has even been... 

Davy prepd in 1831 a similar solvent by mixing HC1 with HNOj It is now usually prepd by mixing 1 vol of coned HNOswith 3-4 vols of coned HC1, The liq is at first colorless, but it gradually becomes orange-yel die to the formation of nitrosyl chloride and free chlorine HNOs+3HCl-----, aj+ZHjO+NOCKnittosylchloride)... 

Formation.—When sulphur dioxide is passed into ice-cold fuming nitric acid, crystals of nitrosulphonic. acid separate.1 The acid is also obtained when sulphuric acid is treated with excess of nitrogen peroxide.2 It is also formed by the interaction of sulphur dioxide and nitrogen peroxide both in the absence or presence of water,8 and by the addition in equimolecular proportion of liquid nitrogen tetroxide to chloro-sulphonic acid in the absence of moisture.4 Sulphuric acid acts on either nitrous anhydride or nitrosyl chloride with formation of nitrosulphonic acid, according to the equations ... 

Constitution.—The formation pf nitrosyl chloride or bromide by the action of the acid on sodium chloride or bromide is evidence in favour of the nitrosylsulphuric acid structure, ON.O.SOa.OH. The... 

It may also be obtained by the action of nitrosyl chloride on sulphuric anhydride. It is a -white, leafy, crystalline mass, somewhat resembling stearic acid in appearance. It is decomposed by moist air with formation of sulphuric, hydrochloric and nitric acids.1... 

Two other termolecular reactions, namely, the formation of nitrosyl chloride and nitrosyl bromide, have in fact small positive coefficients, but very little above unity. 

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