Dinitrogen pentoxide aromatic compounds

Nitrations in acetic anhydride, or in solutions containing benzoyl nitrate ( 5.2) or dinitrogen pentoxide ( 4.2.3) have long been associated with the formation from some aromatics of higher proportions of o-nitro-compounds than are formed under other conditions. 

Expt. 27. A solution of dinitrogen pentoxide (0-005 tnol) in acetonitrile (0-4 ml) was added slowly to the aromatic compound (o-oi mol) in acetonitrile (i ml). 

In earlier chapters we have been concerned with the identification of the effective electrophile in nitrations carried out under various conditions. We have seen that very commonly the nitronium ion is the electrophile, though dinitrogen pentoxide seems capable of assuming this role. We now consider how the electrophile, specifically the nitronium ion, reacts with the aromatic compound to cause nitration. 

Dinitrogen pentoxide (prepared by the oxidation of N204 with 03) in nitric acid is a potent nitration system. It can be used for nitrating aromatic compounds at lower temperatures than conventional system. It is also convenient for preparing explosives that are unstable in nitrating media containing sulfuric acid (Eq. 2.7).20... 

Dinitrogen pentoxide has also been used to synthesize aryldinitromethanes from arylal-doximes in yields between 20 % and 60 Aromatic ring nitration can also occur during these reactions.Dinitrogen pentoxide in chloroform converts a-chlorooximes to the corresponding Q -chloro-Q, Q -dinitro compounds. 

---