Primary intermediates for hair coloring compositions for oxidative dyeing of hair are compounds of the formula (1): wherein R1 and R2 are each independently selected from hydrogen atoms, a C1 to C5 alkyl or hydroxyalkyl group, or R1 and R2 together with the nitrogen atom to which they are attached form a 5 or 6 member cyclic ring optionally containing one or more additional atoms selected from O, N or S atoms, and n is equal to 1 or 2, with the proviso that when n is equal to 2 only one of R1 and R2 may be hydrogen.