Oxocyclopentene derivative-containing dyes giving a wide variety of brilliant, intense shades on keratin fibers, especially human hair, without the need for an oxidizing component

摘要

Dyes for keratin fibers, especially human hair, contain an oxocyclopentene derivative. Dyes for keratin fibers, especially human hair, contain an oxocyclopentene derivative of formula (I): R<1> and R<2> = H or 1-4C alkyl or optionally form a ring; R<3> and R<4> = H, 1-4C alkyl or aryl or optionally form a ring; and X = CH2-, C=O- or C=S-.