| abstract |
A telescoping synthesis of 5-amino-4-nitroso-1-alkyl-1H-pyrazole salt derivatives of formula (I), the compound (I) itself, and its use as an intermediate in the fabrication of 1-alkyl-4,5-diaminopyrazole salts of general formula (IX). The compounds of formula (IX) can be used as precursor dyes in oxidative hair dye compositions. n n n n n n n n n n R is a mono- or poly-substituted or unsubstituted, straight or branched, saturated or mono- or poly-unsaturated, alkyl group. HZ and HZ′ are organic or mineral acids. |