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Conventional nitrations use electrophilic reagents as the attacking species, and therefore electron-deficient substrates, such as certain nitrogen heterocycles and polynitroaromatics, react very slowly, giving low yields and extensive by-product formation. Because such substrates generally react readily with nucleophiles in high yield, reactions of heterocycles and polynitroaromatics with certain specific nucleophiles were therefore investigated with a view to generating intermediates containing 'masked' nitro groups, which could then be converted to nitrated products by simple oxidation procedures. The method was applied to the nitration of several electron-deficient carbocyclic (i.e. benzenoid) or heterocyclic aromatic compounds, notably pyridines and diazines (pyrimidines and pyrazines). The methodology comprised:i) reacting a haloaromatic with a diarylsulphilimine or its Nalkali metal salt, thereby generating an N-(hetero)aryl-S,S-diarylsulphilimine derivative, and ii) oxidising this intermediate under relatively mild conditions using a peroxycarboxylic acid such as m-chloroperbenzoic acid. Moderate to good yields of the corresponding nitro products, including some previously unreported compounds, were obtained. In certain cases the first step could be accomplished without the necessity of a halo precursor, i.e. by vicarious nucleophilic substitution. An attempted extension of the methodology to the aliphatic series, where phosphinimines were also employed as nucleophiles, was, however, largely unsuccessful.

Novel syntheses of polynitroaromatic compounds by reversed-dipole (‘Umpolung’) nitrations1