GB410857A - Manufacture of hydroxynaphthotriazoles - 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 diazo compound in an acid medium with an aminonaphtholsulphonic acid. The following examples are specified. (1) The dyestuff aniline --> (acid) 2 : 5 : 7-aminonaphtholsulphonic acid is boiled in sodium carbonate solution with an addition of copper sulphate, the cuprous oxide formed is removed by filtration and the triazole is salted out; the product couples with diazo compounds; the aniline may be replaced by aniline-2-sulphonic acid. (2) The dyestuff 4-nitraniline --> (acid) 1 : 8 : 3 : 6-aminonaphtholdisulphonic acid is treated in sodium carbonate solution at 20 DEG C. with a copper sulphate solution and the triazole which separates is filtered off and purified by solution in aqueous sodium carbonate and filtration; the product couples with diazo compounds; alternatively the oxidation may be effected in ammoniacal solution, or the acid mixture obtained in the manufacture of the initial dyestuff may be boiled with copper chloride solution; the 4-nitraniline may be replaced by 3-nitraniline or 4-chloraniline. (3) The dyestuff 4-nitraniline --> (acid) 2 : 5 : 7-or 2 : 8 : 6-aminonaphtholsulphonic acid is boiled in sodium carbonate solution with an addition of copper sulphate and hydrogen peroxide and after dilution and a further addition of sodium carbonate the cuprous oxide is removed by filtration and the triazole is salted out; the product couples with diazo compounds. (4) The dyestuff 4-nitraniline --> (acid) 2 : 5 : 7-aminonaphtholsulphonic acid is boiled in sodium carbonate solution with an addition of copper sulphate and sodium hypochlorite, and the triazole is isolated as in (3) or used directly for coupling with diazo compounds. (5)--(9) The dyestuffs 4 : 6-dinitro-2-aminophenol --> (acid) 2 : 5 : 7-aminonaphtholsulphonic acid, 4-amino-4<1>-nitrodiphenylamine-2<1>-sulphonic acid --> (acid) 2 : 5 : 7-aminonaphtholsulphonic acid, 1-amino-4-nitronaphthalene-6-sulphonic acid --> (acid) 2 : 5 : 7-aminonaphtholsulphonic acid, 4-nitraniline --> (acid) 1 : 8 : 4-aminonaphtholsulphonic acid and 4-aminoazobenzene-4<1>-sulphonic acid --> (acid) 2 : 5 : 7-aminonaphtholsulphonic acid respectively are boiled in sodium carbonate solution with an addition of copper sulphate, the cuprous oxide is separated by filtration and the triazoles are salted out; the product in each case couples with diazo compounds. Specification 410,765 is referred to.