Di-o-nitrophenyl disulphide

Aminobenzenesulphonic acid (orthanilic acid, Expt 6.64) is readily prepared by the reduction of 2-nitrobenzenesulphonic acid. The latter may be prepared by the hydrolysis of the corresponding sulphonyl chloride which is obtained from di-o-nitrophenyl disulphide. The preparation of this disulphide involves the use of the reactive aryl halide, 2-chloronitrobenzene (cf. Expts 6.93... 

N-ammonia in methanol. Upon oxidation to the cyclic disulphide Wittinghofer noted the formation of small amounts of di o-nitrophenyl disulphide which may have resulted from -> S-o-nitrophenylsulphenyl group migration during the alkaline removal of the S-ethylcarbamoyl group. 

Mercury di-o-nitrophenyl occurs in pale yellow needles, M.pt. 206 to 207° C., easily soluble in pyridine, hot acetone, and carbon disulphide, sparingly in carbon tetrachloride. Yield 92 per cent. When boiled with concentrated hydrochloric acid nitrobenzene is split off. 

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