Prepn: p-Nitrosodimethylaniline hydrochloride, obtained by reacting dimethylaniline and sodium nitrite, is condensed with 2,4-dinitrotoluene in the presence of sodium carbonate. The product, dinitrobenzylidene-p-aminodimethylaniline is split under steam agitation with HCl: Bennett, Bell, Org. Synth. coll. vol. II, 223 (1943).