GB708663A - Manufacture of new trisazo dyestuffs - Google Patents

Abstract

The invention comprises trisazo dyestuffs of the formula <FORM:0708663/IV(c)/1> where R1 and R2 are residues of middle component of the benzene series and R3 is the residue of a benzene-o-hydroxycarboxylic acid; the attachments shown to the ring I are m- or p-. These are made by coupling diazotized 2-naphthylamine-4:8-disulphonic acid with HR1 NH2, re-diazotizing, coupling with HR2 NH2, condensing the product with m- or p-nitrobenzoyl chloride, reducing the nitro group to amino, diazotizing and coupling with salicylic acid or a substitution derivative thereof. The last coupling may be effected in the presence of pyridine. Preferably no carboxylic acid group is present other than that in R3. The products are suitable for dyeing and printing wool, silk, leather, cotton, linen and regenerated cellulose. They can be metallized (especially coppered) in the dyebath or on the fibre, e.g. by the process of Specifications 455,274 or 619,969. In examples, (1) the dyestuff 2 - naphthylamine - 4 : 8 - disulphonic acid --> m - toluidine --> m-toluidine (p-nitrobenzoylated and reduced) is diazotized and coupled with salicylic acid; (2) as in (1) using cresidine as first coupling component; (3) cotton is dyed with the product of (2) and coppered. Other suitable components are listed.