Aniline derivatives are dye precursors used for what type of hair color?

• A. Nitro compounds
• B. Azo dyes
• C. Aniline derivatives
• D. Leuco dyes

Answer: (C)

Aniline derivatives are used as dye precursors in oxidative hair color because they provide the amino-containing starting materials that are oxidized and then coupled to form the colored dye molecules inside the hair fiber. In these systems, hydrogen peroxide oxidizes the primary intermediates, which can then react with couplers to build up a stable, lasting color. The key idea is that these compounds are not the final color themselves; they are transformed through the oxidation/coupling reactions into the actual dye that stays in the hair. Nitro compounds and leuco dyes aren’t the typical precursors used in standard salon colorings, and while the final colors often fall into the azo dye class, the question is identifying the precursor type, which points to the aniline derivatives themselves.