aniline (cold) and mordant Gallocyanine?[by excessive amounts of ?N,N-dimethyl-4-nitrosobenzenamine and Gallic acid Methanol in the reaction (in ethanol in reaction incomplete) and be] hydrochloride (or corresponding diethyl compound) reaction, in 100 ℃ to remove carboxyl, then sulfonation and translated into sodium salt.
Chromazurin 42 is synthesized anal ogously but in the cold. Under these conditions the aniline group bonds to the position neigh boring the carboxyl group, which is removed by subsequently heating to 100 ℃.