The oxidation of a mixture of N-tert-butyl- p-toluidine/aniline/ o-toluidine (1: 1.5: 1.5) with K2Cr2O7 in H+/H2O followed by de- tert-butylation with acid gives mauveine A and mauveine B. These compounds dye silk the same shade of red mauve as that of silk dyed by authentic mauveine.