2-Nitroaniline → 4,4'-Bis-(o-nitroanilino) biphenyl

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Reaction Steps

4,4'-Dibromobiphenyl (156 g., 0.5 mole) was condensed with o-nitroaniline (138 g., 1.0 mole) using cuprous iodide catalyst and anhydrous sodium carbonate as an acid acceptor in refluxing nitrobenzene (500 ml) during 16 hours. The resulting 4,4'-bis-(o-nitroanilino) biphenyl, obtained in 85% yield, was reduced with sodium sulfide in ethylene glycol at 150° to 200° C. The yield of 4,4'-bis(o-aminoanilino)biphenyl was 132 g. (72% yield, mp 211°-222° C.). The melting behavior of the compound is unusual. Differential Scanning Calorimetry (DSC) analysis provides two endotherms; one at 211° C. and one at 222° C. Depending on the thermal history of the amine, either melting point (or combination) is observed. The amine assay by acetylation was 16.2, theory 16.93. The elemental analysis provided the following:

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