Patent GB-562762-A (GB)
Title: New azo dyestuffs
IPC: C09B39/00
Filed: 1942-07-13
Abstract: Azo dyes are obtained by coupling a diazotised arylamine with a 2 : 4-diarylpyrrole, which may be substituted in the 3-position. When the diazo component carries a metal-complex-forming group in o-position to the amino group, the products are capable of conversion into metal complex compounds in substance or on the fibre.  The products containing one or more sulphonic acid or other solubilizing groups are suitable for dyeing wool and, in some cases, cotton.  Those free from solubilizing groups are applicable as pigments.  Specified diazo components are 3-chloroaniline, 4- or 5-nitro-2-aminoanisole, 2 : 5 - dichloroaniline, 3 - amino - carbazole, 4 - benzoylamino - 2 : 5 - dimethoxy - aniline, 3 - nitro - 4 - aminotoluene, 5 - nitro - 2 - aminotoluene, 2-nitro-4-chloroaniline, 4-chloro-2-aminotoluene, aniline-2 : 5-disulphonic acid, 4 : 6 - dinitro - 2 - aminophenol, picramic acid, 2 - chloro - 4 - aminophenetole, 4-aminodiphenyl, 4 - chloro - 2 - aminophenol and its 6 - sulphonic acid, anthranilic acid and its 4-sulpho derivative, 4- or 5-nitro-2-aminophenol, 1-aminonaphthalene, 1-aminoanthraquinone, 1 : 2-aminonaphthol-4-sulphonic acid, benzidine and its 3 : 31-dichloro, 3 : 31-dicarboxy, 2 : 21-disulpho and 3 : 31-di-(carboxymethoxy) derivatives, dianisidine, 4 : 41 - diaminodiphenylamine, 4 : 41 - diaminobenzanilide-31-carboxylic acid, 4 : 41-diaminostilbene-2 : 21-disulphonic acid, 3-nitro4 - aminotoluene \sQ cresidine, 4 - aminoazo - benzene -41-sulphonic acid and 3-amino-2 : 4-diphenylpyrrole. Specified coupling components are 2 : 4 - diphenylpyrrole, 2 - phenyl - 4 - (p - methoxyphenyl) -pyrrole, 2-(p-methoxyphenyl)-4 - phenyl - pyrrole, 2 - (m - hydroxyphenyl) - 4 - phenyl - pyrrole, 2 - (o - chlorophenyl) - 4 - phenyl - pyrrole, 2 - (p - acetylaminophenyl) - 4 - phenyl - pyrrole, 2 - (a  - naphthyl) - 4 - phenyl - pyrrole, 2 - phenyl - 4 - (b  - naphthyl) - pyrrole and 2 : 3 : 4 - triphenylpyrrole (cf. Specifications 554,102 and 556,156), the 3-benzoylamino, 3-acetylamino and 3-acetoacetylamino derivatives of 2 : 4-diphenylpyrrole, 3 - benzoylamino - 2 : 4 - di - (p - tolyl) -pyrrole and the mono- and di-sulphonic acids of 2 : 4-diphenylpyrrole (cf. Specification 562,753).  Examples relate to the production of the dyestuffs, (1) aniline-2 : 5-disulphonic acid \sQ 2 : 4-diphenylpyrrole, which dyes wool, from an acid bath, orange-brown; (2) 4-chloro-2-aminotoluene or 3-nitro-4-aminotoluene \sQ 2 : 4-diphenylpyrrole or 3 : 31-dichlorobenzidine \sQ 2 : 4-diphenylpyrrole (2 mols.), which are pigments; (3) 4 : 6-dinitro-2-aminophenol \sQ the monosulphonic acid of 2 : 4-diphenylpyrrole, which is suitable for dyeing wool by the metachrome or the after-chrome process; (4) benzidine or 4 : 41-diaminostilbene-2 : 21-disulphonic acid \sQ the disulphonic acid of 2 : 4-diphenylpyrrole (2 mols.), which are suitable for dyeing cotton; (5) 4-aminoazobenzene-41-sulphonic acid \sQ the disulphonic acid of 2 : 4-diphenylpyrrole, which dyes cotton bluish red; (6) 4 : 41 - diamino - 3 : 31 - di - (carboxymethoxy) - diphenyl \sQ the disulphonic acid of 2 : 4-diphenylpyrrole (2 mols.), which dyes cotton bluish violet, becoming blue on after-coppering; (7) 4 : 41 - diamino - 3 : 31 - dicarboxy - diphenyl \sQ the disulphonic acid of 2 : 4-diphenylpyrrole (2 mols.), which dyes cotton violet, becoming greenish blue on after-coppering; (8) 4 : 41 - diaminobenzanilide - 31 - carboxylic acid \sQ the disulphonic acid of 2 : 4-diphenylpyrrole (2 mols.), which dyes cotton reddish orange, becoming dull violet on after-coppering; (9) 4 : 41-diaminobenzanilide-31-carboxylic acid \sQ salicylic acid (1 mol.) and the disulphonic acid of 2 : 4-diphenylpyrrole (1 mol.), which dyes cotton reddish orange, becoming grey on after-coppering.  4 : 41-Diaminobenzanilide - 31 - carboxylic acid is obtained by reduction of the condensation product from 6-nitro-3-aminobenzoic acid and 4-nitrobenzoyl chloride.  3 - Acylamino - 2 : 4 - di - p - tolyl - pyrroles are obtained by acylation with the appropriate acid halide or anhydride of 3-amino-2 : 4-di-p-tolylpyrrole, obtained by treating with mineral acid the anhydro-bis-phenacylamine resulting from the action of alkali on the salt of 4-methyl-aminoacetophenone resulting from the reduction of the product of reaction of amyl nitrite with 4-methylacetophenone.