Alkylation of benzthiazole-azo-phenylamine dyestuffs

Process for the preparation of an alkylated dyestuff, wherein a benzthiazole dyestuff of the formula ##STR8## wherein R.sub.1 and R.sub.2 independently of one another denote hydrogen, alkyl, alkenyl, cycloalkyl, aryl or aralkyl, or, when joined together are pyrrolidinyl, piperidinyl, or morpholinyl;

• R.sub.1, in addition, when joined to the ortho-position of ring B, forms dihydroindolyl, tetrahydroquinolinyl, or hexahydrocarbazolyl;
• rings A and B are unsubstituted or substituted with fluoro, chloro, bromo, nitro, cyano, formyl, ureido, aminocarbonyl, aminosulphonyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkylcarbonyl, C.sub.1 -C.sub.4 -alkylcarbonyloxy, C.sub.1 -C.sub.4 -alkoxycarbonyloxy, C.sub.1 -C.sub.4 -alkylcarbonylamino, C.sub.1 -C.sub.4 -alkylaminocarbonyloxy, C.sub.1 -C.sub.4 -alkylsulphonylamino, C.sub.1 -C.sub.4 -alkylureido, C.sub.1 -C.sub.4 -alkoxycarbonylamino, C.sub.1 -C.sub.4 -alkylaminocarbonyl, C.sub.1 -C.sub.4 -dialkylaminocarbonyl, N-C.sub.1 -C.sub.4 -alkyl-N-phenylaminocarbonyl, C.sub.1 -C.sub.4 -alkylaminosulphonyl, C.sub.1 -C.sub.4 -dialkylaminosulphonyl, C.sub.1 -C.sub.4 -alkylsulphonyl, C.sub.1 -C.sub.4 -alkoxysulphonyl-C.sub.1 -C.sub.4 -alkylamino, C.sub.1 -C.sub.4 -alkylsulphonyl-C.sub.1 -C.sub.4 -alkylamino, phenoxy, naphthoxy, phenoxy-C.sub.1 -C.sub.4 -alkoxy, naphthoxy-C.sub.1 -C.sub.4 -alkoxy, phenylthio, naphthylthio, phenylcarbonyl, naphthylcarbonyl, phenoxycarbonyloxy, naphthoxy-carbonyloxy, phenylcarbonyloxy, naphthylcarbonyloxy, phenylcarbonylamino, naphthylcarbonylamino, phenylaminocarbonyloxy, naphthylaminocarbonyloxy, phenylsulphenylamino, naphthylsulphonylamino, phenylsulphonyl-C.sub.1 -C.sub.4 -alkylamino, naphthylsulphonyl-C.sub.1 -C.sub.4 -alkylamino, phenylureido, naphthylureido, phenoxycarbonylamino, naphthoxycarbonylamino, phenylsulphonyl, naphthylsulphonyl, phenoxycarbonyl, naphthoxycarbonyl, phenoxysulphonyl, naphthoxysulphonyl, benzoxy, phenylethyloxy, benzylthio, phenylethylthio, benzylcarbonyl, phenylethylcarbonyl, benzylsulphonyl, phenylethylsulphonyl, benzoxycarbonyl, phenylethyloxycarbonyl, cyclopentyl, cyclohexyl, cyclopentyl-C.sub.1 -C.sub.4 -alkoxy, cyclohexyl-C.sub.1 -C.sub.4 -alkoxy, a fused benzene ring, or a fused tetrahydrobenzene ring;
• the process wherein said dyestuff is alkylated with an ester of the formula
• R.sub.3 --SO.sub.3 R
• wherein
• R is alkyl and
• R.sub.3 is aryl or alkoxy;
• in an organic solvent immiscible with water, the alkylation being brought to completion at 30.degree. C. to 80.degree. C. after addition of 5-100% by volume of the reaction volume of water and 0.05-0.5 mol, relative to the amount of dyestuff, of the alkylester employed for alkylation.