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Please login or sign up for a free trial to access the full content. Method 45: Substitution of Hydrogen Using Dinitrogen Pentoxide and Sulfur Dioxide

DOI: 10.1055/sos-SD-031-01277

Aitken, K. M.; Aitken, R. A.Science of Synthesis, (2007311245.

Benzene and monosubstituted derivatives are nitrated with a dinitrogen pentoxidesulfur dioxide adduct,[‌250‌] but this reagent has become most important in the nitration of pyridines to give 109 (Scheme 79). Although the original method required liquid sulfur dioxide, a more convenient alternative has appeared, involving initial treatment with dinitrogen pentoxide followed by reaction of the resulting N-nitropyridinium salt with sodium hydrogen sulfite in aqueous methanol.[‌251‌] Various substituents are tolerated in the pyridine ring. The method, including the reaction mechanism, has been reviewed by its developer.[‌252‌]

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