Dinitro compounds, aromatic, partial reduction

Some aromatic dinitro compounds, e.g. w-dinitrobenzene, may be characterised by partial reduction to the nitroamine. Experimental details using sodium polysulphide as the reducing agent are to be found in Expt 6.51. 

Selective hydrogenation of one or two nitro groups in an aromatic dinitro compound is the basis for the synthesis of otherwise unattainable molecules. Carefully chosen catalysts, under totally different reaction conditions, have been met with success. Partial reduction of 2,6-dinitroanilines to nitrophenylenediamines occurs in 60-90% yield over 10% palladium-on-carbon at RT [equation (a)], although most heterogeneous catalysts do not afford such selectivity. 

Some aromatic dinitro-compounds may be characterized by partial reduction to the corresponding nitro-amines. 

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