The invention relates to a cosmetic composition, especially a hair composition, and to a method for the cosmetic treatment of keratin materials, especially of the hair, employing compounds of formula:in which Z represents (i) a hydrogen atom, (ii) a linear or branched C1 to C32 (saturated) alkyl radical (iii) a linear or branched C2 to C32 (unsaturated) alkene radical, comprising one or two C═C double bonds (iv) an aryl-substituted alkyl radical said radicals being optionally substituted and/or interrupted.
