PROCESS FOR THE PRODUCTION OF CATIONIC HYDRAZONE DYES

Dyestuffs of the general formula (I) wherein R1 denotes alkyl, alkenyl, aralkyl or cycloalkyl, R2 denotes hydrogen, alkyl, alkenyl, aryl, aralkyl or cycloalkyl, or alkylene bonded to the ring a, R3 denotes hydrogen or one or more non-ionic substituents customary in dyestuff chemistry and X- denotes an anion, wherein an aromatic or cycloaliphatic ring can be fused to the ring a, and wherein the radicals mentioned can carry non-ionic substituents customary in dyestuff chemistry, are obtained, if 4-methylpyridine is treated with a quaternizing agent of the formula R1-X (II) wherein X denotes a group which can be split off in the form of the anion X-, within a temperature range from -20 DEG C. up to the boiling point of the system, the resulting reaction product is reacted with a base and a nitrite of the formula R-O-N=O (III) wherein R denotes an organic radical, within a temperature range from -20 DEG C. to +60 DEG C., and the product is then reacted, at a pH value below 7, with a hydrazine of the formula (IV) or with a hydrazosulphonate of the formula wherein M+ represents a monovalent metal cation or an organically substituted ammonium cation or one equivalent of a divalent cation, within a temperature range from -20 DEG C. up to the boiling point of the system, and the product is reacted, if appropriate, if R2 is initially hydrogen and is intended to be different from hydrogen in the final product, with a compound of the formula R2-X (VI) wherein R2 denotes alkyl, alkenyl or aralkyl.