Synthesis of reactive dyes for wool employing isocyanate bisulphite adducts

Abstract

Syntheses of azo dyes which incorporate a bisulphite-isocyanate adduct as a ?masked? reactive group are described. Two general methods are used. One is based on couplings with diazotized sodium 4- aminobenzylaminooxomethanesulphonate (2). The other is achieved by coupling aromatic dia- zonium salts with sodium 6-(3?- dimethylaminophenylureido)hexylaminooxomethanesulphonate (4). The synthesis of (4) involves monofunctional addition of an arylamine to hexamethylene diisocyanate.