Primary intermediates for hair coloring compositions for oxidative dyeing of hair are compounds of the formula (1): ##STR00001## wherein R.sub.1 and R.sub.2 are each independently selected from hydrogen atoms, a C.sub.1 to C.sub.5 alkyl or hydroxyalkyl group, or R.sub.1 and R.sub.2 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 R.sub.1 and R.sub.2 may be hydrogen.