Couplers for hair coloring compositions for oxidative dyeing of hair are compounds of the formula (1): where R1 and R2 are each individually selected from a hydrogen atom, a C1 to C3 alkyl group, a C1 to C5 mono or dihydroxyalkyl group; phenyl or benzyl optionally substituted with an alkoxy group, or R1 and R2 together with the nitrogen atom to which they are attached form a piperazine, piperidine, imidazole, or morpholine ring.