GB1389915A - Water soluble azo dyestuffs - Google Patents

Abstract

1389915 Azo dyestuffs containing nitro and sulpho groups SANDOZ Ltd 12 May 1972 [17 May 1971] 22267/72 Heading C4P Novel water-soluble azo dyestuffs of the formula wherein R 1 is an optionally substituted aromatic or heterocyclic radical, R 2 is an optionally substituted aromatic or heterocyolic radical or the radical of a coupling component other than included in R 1 , the A ring is optionally further substituted, and the molecule contains one or two SO 3 H groups are prepared (a) by reacting an amine R 1 NH 2 with a compound of the above formula but containing in place of -NHR 1 a group X replaceable by -NHR 1 ; or (b) by coupling the diazo compound from an appropriate 4-NHR 1 -3-nitro-aniline with a coupling component R 2 H. Products wherein R 2 is a phenyl or naphthyl radical containing a phenolic OH group may be etherified or acylated by reaction with a compound R 3 X 1 in which R 3 is aryl, alkylcarbonyl, arylcarbonyl, alkylsulphonyl or arylsulphonyl and X 1 is halogen or R 3 is optionally substituted alkyl and X 1 is halogen or a sulphate radical. In process (a) X may for example be a halogen atom or an arylsulphonyloxy or alkoxy radical. 4-Chloro- 4<SP>1</SP>-methoxy-3-nitro-1,1<SP>1</SP>-azobenzene is prepared by methylation of the corresponding 41-hydroxy compound. 4-Chloro-4<SP>1</SP>-tosyloxy-3-nitro-1,1<SP>1</SP>-azobenzene is prepared by tosylation of the same starting material. The novel dyestuffs are useful for dyeing and printing natural and synthetic polyamide fibres, natural and regenerated cellulose fibres, polypropylene fibres modified by the introduction of basic groups, paper and leather in yellow to yellow-brown shades.