Nitration aromatics with dinitrogen tetroxide

It was Schaarschmidt [43] who first investigated the catalytic efl eci of AICI3 and FeCl3 on the nitration of aromatics with dinitrogen tetroxide,... 

Aromatic substrates containing Lewis basic substituents can undergo ort/io-lithiation. Quenching these anions with dinitrogen tetroxide at low temperature is an example of nucleophilic aromatic nitration." Similar examples have been reported with anions generated from Grignard reactions with arylhalides." ... 

Germain, A., Akouz, T. and Figueras, F. Vapour-phase aromatic nitration with dinitrogen tetroxide over solid acids kinetics and mechanism, J. Catal., 1994, 147, 163-170. 

Dinitrogen tetroxide forms a stable complex with boron trifluoride but this is a weak nitrating agent. Aromatic nitrations with other Lewis acids have been reported, including AICI3, FeCls, TiCU, BCI3, PF3, BF3, AsFs and SbFs. i " ... 

Pioneering work performed by Suzuki et al. using dinitrogen tetroxide and ozone,[40] or dinitrogen tetroxide with oxygen and a catalyst[41] for the nitration of aromatics, showed to be an alternative approach towards clean nitration. However, the isomeric composition of the nitration products obtained is similar in most cases to those of classical nitration based on nitric and sulfuric acids. 

Pinck (.3 ) used sulfuric acid to catalyze the nitration of aromatics with N20i. He observed that only half of the dinitrogen tetroxide was used up in the nitrations, the remainder being present as nitrosyUSulfuric acid. Titov (3 ) dissolved N20[ in sulfuric acid and used this solution as nitrating agent. 

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