N,n-bis(2-hydroxyethyl)-2-nitro-p-phenyldiamines (inci)

N,N-bis(2-hydroxyethyl)-2-nitro-p-phenyldiamine sulfate is a substance used as a permanent hair dye in cosmetic formulations. They cause a permanent coloration of the hair matrix (hair keratin). N,N-bis(2-hydroxyethyl)-2-nitro-p-phenyldiamine sulfate belongs to the colorless oxidation bases in the process of permanent hair dyeing of hair keratin. These are easily oxidizable, initially colorless dye bases. Principle: The dye bases migrate into the hair shaft swollen by the alkaline medium. There they are oxidized to complex dyes, whereby they chemically bind with the hair keratin. Only through the oxidation of the (colourless) dye bases by the hydrogen peroxide the actual dye is formed.

https://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_019.pdf