GB446756A - Manufacture of oxynaphthotriazoles - Google Patents

Abstract

Hydroxynaphthotriazoles which are valuable intermediates for dyestuffs are obtained by oxidizing with a compound of bivalent copper or with another oxidizing agent in presence of a copper compound, an o-aminoazo dyestuff obtained by coupling a diazotized aminonaphtholsulphonic acid, not containing the amino and hydroxy groups in o-position to one another, with a component of the benzene or naphthalene series (other than an aminonaphtholsulphonic acid or a m-aminophenol) which contains in o-position to the coupling position an amino group or a group which, after the coupling, is converted into an amino group. The following examples are specified: (1) The dyestuff, 2 : 5 : 7-aminonaphtholsulphonic acid --> 4-nitro-1 : 3-diaminobenzene, is treated in dilute sodium carbonate solution at 80 DEG C. with copper sulphate solution saturated with ammonia and the resulting triazole is salted out; the 2 : 5 : 7-acid may be replaced by 2 : 8 : 6-aminonaphtholsulphonic acid or 1 : 8 : 3 : 6-aminonaphtholdisulphonic acid; in the latter case the product may be isolated by evaporating the solution; (2) The dyestuff, 2 : 8 : 6-aminonaphtholsulphonic acid --> 1 : 3-diaminobenzene, is treated in boiling sodium carbonate solution with copper sulphate, cuprous oxide is filtered off and the triazole is salted out from the filtrate; (3) The dyestuff, 1 : 8 : 3 : 6 - aminonaphtholdisulphonic acid --> 2-naphthylamine, is treated in sodium carbonate solution at 80 DEG C., with copper sulphate solution saturated with ammonia, the temperature is raised to the boil to remove the ammonia, and the triazole is salted out; the ammoniacal copper solution may be replaced by a solution containing copper sulphate and hydrogen peroxide or cupric chloride and sodium hypochlorite. The products in all the examples couple with diazo compounds.