Nucleophilic Aromatic Substitution of Hydrogen NASH

Fullerene is nitrated with N204 to give hexanitro[60]fiillerene C60(NO2)4, which undergoes SNAr reaction with various nucleophiles.32 

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Nucleophilic displacements on unsubstituted aromatics usually do not occur since H is not a good leaving group. However, an example of nucleophilic aromatic substitution of hydrogen (NASH) has been reported on reacting aniline and azobenzene in the presence of base under aerobic conditions to generate 4-(phenylazo)diphenylamine, 9 (equation 13)115. 

Flexsys found a solution to this problem in a class of reactions known as nucleophilic aromatic substitution of hydrogen (NASH). Through a series of experiments designed to probe the mechanism of NASH reactions, Flexsys achieved a breakthrough in understanding... 

The formation of substituted anilides from the reaction of amides with nitrobenzene is the first example of the direct formation of aromatic amide bonds via nucleophilic aromatic substitution for hydrogen. This reaction proceeds in high yield and regioselectivity, and does not require the use of halogenated materials or auxiliary leaving groups. Furthermore, these studies have demonstrated that the use of O2 as the terminal oxidant in NASH reactions can result in a highly selective and environmentally favorable route for the production of PNA and PPD. 

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