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NITRATION AGENTS AND METHODS MORE RARELY USED^97

Nitrosate (II) Nitro-nitrate (IIa)

Nitro-nitrite (IIb) Dinitro compound (III) Dinitrite (IV)

Riebsomer [72] gave an extensive list of the reactions of NO 2 addition to un-

saturated compounds.

Guthrie [73] obtained the first nitrosate in 1860 by treating amylene with nitro-

gen dioxide. Wallach [74] found it to be a well defined compound, while this is

not the case with the amylene and N 2 O 3 compound.

Although no amine was produced by the reduction of amylene nitrosate, and

only ammonia was formed, Wallach inferred from the results of the experiments

described below that the compound had the structure V.

By heating amylene nitrosate (V) with aniline in an alcoholic solution, amylene-

nitrosoanilide (VI) was formed, which under the influence of nitrous acid gave

the N-nitroso compound (VII):

V VI VII

m. p. 140-141°C

The reaction was later widely used by Wallach for the identification of terpenes,

which formed well defined, crystalline nitrosates and nitrosites and also by

Jagelki [75] and Lipp [3].

Extensive research work on the action of N 2 O 3 , N 2 O 4 and N 2 O 5 on olefins was

carried out by Demyanov [76, 77, 78]. He found that both glycol esters and nitro

compounds were obtained in these reactions. According to Wieland [13,55], the

reaction of N 2 O 4 with stilbene results in the formation of dinitrostilbene (VIII):

VIII

The addition of N 2 O 4 to compounds with conjugated double bonds takes place

in a way similar to the addition of halogens to these compounds. For example
1,4-diphenylbutadiene is converted to 1,4-diphenyl-1,4-dinitrobutylene-2 (IX) :