Isonitroso hydrogen

The same kind of isomerization can also be enforced in the parent compound, namely nitrosohydrogen HNO (150).198 Matrix irradiation of 150 leads to isonitroso hydrogen NOH (151). Calculations of the potential-energy surface of the system HNO/HON show a singlet ground state for HNO 150, which is also the global minimum.199 200 However, for HON 151 a triplet ground state is predicted. Indeed, the experimental IR spectrum of 151 fits much better the calculated spectrum of the triplet. Thus, the isomerization 150 151 involves... 

Aliphatic nitro compounds with the nitro group on a tertiary carbon were reduced to amines with aluminum amalgam [146 or iron [559]. 2-Nitro-2-methylpropane afforded ferf-butylamine in 65-75% yield [146. Even some secondary nitroalkanes were hydrogenated to amines. fra s-l,4-Dinitrocy-clohexane was converted to frans-l,4-diaminocyclohexane with retention of configuration. This may be considered as an evidence that the intermediate nitroso compound is reduced directly and not after tautomerization to the isonitroso compound [560] (see Scheme 54). 

Phenylpropanolamine Phenylpropanolamine, D,L-erythro-1 -phenyl-2-methylamino-propanol-1 (11.3.7), is synthesized from propiophenone by nitrosation into an isonitroso derivative (11.3.6). Reduction of this by hydrogen in hydrochloric acid while simultaneously using two catalysts, palladium on carbon and platinum on carbon, gives norephedrine (11.3.7) [56-59]. 

The nitrosation of aliphatic carbon atoms, particularly of carbon atoms activated by adjacent carbonyl, carboxyl, nitrile, or nitro groups, has been reviewed in great detail [2]. Judging from this review, with few exceptions, nitrosation of active methylene compounds leads to the formation of oximes (unfortunately termed isonitroso compounds in the older literature). The few exceptional cases cited in which true nitroso compounds (or their dimers) were formed involved tertiary carbon atoms in which no hydrogen atoms were available to permit tautomerism to the oxime or involved a reaction which was carried out under neither acidic nor basic conditions. 

Aliphatic nitro compounds are reduced to various products, in all the published examples, only C-F bonds at a-positions are reduced, while the nitro group can be reduced in two steps. Catalytic hydrogenation of primary nitro compounds over palladium transforms them to the corresponding isonitroso compounds, i. e. oximes, while secondary nitro groups are converted into amines (Table 4). The reduction with Raney nickel alloy converts all types of nitro compounds into the corresponding amines, e. g. formation of 14.136... 

The reduction of isonitroso ketones with hydrogen and platinum in the presence of hydrochloric acid gives amino ketones or amino alcohols, e.g., l-phenyl-2-amino-l-propanol (98%) and a-aminopropiophenone (88%). ... 

The reaction of 2, 5 -dimethoxypropiophenone with nitrous acid gives the corresponding 2-isonitroso derivative, which on catalytic hydrogenation, yirst reduces the keto function, and secondly converts the nitroso group into an amino function. The methoxamine base when dissolved in an appropriate solvent and subjected to a stream of hydrogen chloride gas yields the official compound. 

Platinum oxide hydrogen chloride a-Amino- from a-isonitroso-ketones s. 17,29... 

A mixture of 10-isonitroso-cis-l,2,3,4,4a,10a-hexahydro-9-phenanthrone, PtOg, some 38%-HCl, and methanol hydrogenated 20 min. at room temp, and atmospheric pressure 10-amino-cis-l,2,3,4,4a,10a-hexahydro-9(10H)-phenanthrone hydrochloride. Y 78%. J. G. Murphy, J. Org. Chem. 26, 3104 (1961). 

A-Methyl-2-(a-isonitroso-a-cyano) methylbenzimidazole, see H-00244 Methylisoselenourea hydrogen sulfate, in... 

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