Rearrangement of triazenes

If formed, the triazene can often be converted into the amino azo compound by even gentle warming with dilute acid this conversion is smoother if the triazene is warmed with the amine used for coupling and a small amount of its hydrochloride.368 The acid-catalysed rearrangement of triazenes involves intermediate reformation of the diazonium salt and the amine.369,370 So, if rearrangement of a triazene is carried out in the presence of a different, more readily coupling amine, the diazonium component reacts preferentially with the latter e.g., A,ALdimethyl-/ -(phenylazo)aniline is obtained from diazoaminobenzene and N,N-di-methylaniline.368... 

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