Patent GB-578268-A (GB)
Title: Process for the manufacture of new amides and of azo dyestuffs obtainable therefrom
IPC: C07D277/82
Filed: 1942-02-06
Abstract: Amides, suitable for use as coupling components in the manufacture of azo dyestuffs in substance or on a substratum such as a textile material, e.g. of cotton, regenerated cellulose, silk, wool or ramie, are obtained by condensation of a 2-aminoarylenethiazole with a 2 : 3-hydroxynaphthoic acid capable of coupling with a diazo compound in o-position to the hydroxy group, the acid being used, if desired, in the form of a halide thereof, or the acid itself being heated with the 2-aminoarylenethiazole and a dehydrating agent, e.g. phosphorus trichloride or oxychloride, in the presence of a diluent which may also act as an acid binding agent.  Specified 2-aminoarylenethiazoles are 2-aminobenzthiazole and its 6-chloro-, 6-methyl-, 6-methoxy-, 6-ethoxy-, 6-phenyl-, 4 - methyl- and 6 - chloro - 4 - methyl - derivatives, 2 - amino - 6 : 7 - benzobenzthiazole and its 21-methoxy derivative and 2 : 21-diamino-diarylenethiazoles such as those obtainable by condensation of an appropriate diamine, e.g. benzidine, tolidine, or 4 : 41-diaminodiphenyl ether, (1 mol.) with thiocyanic acid (2 mols.).  Specified 2 : 3-hydroxynaphthoic acids are 2 : 3-hydroxynaphthoic acid itself and its 6-bromo- and 6-anilino derivatives.  A list is given of suitable diazo, diazoazo and tetrazo components for use in the ice-colour process for the production of azo dyestuffs on the fibre, or, in the form of N-nitrosamines or water-soluble salts of diazoamino compounds, in printing processes. Particularly suitable components are those containing more than one phenyl nucleus, especially phenyl or benzyl ethers of o-aminophenols, e.g. 2-amino-21-, 31- or 41-methyl-4-chlorodiphenyl ether and 2-amino-21 : 41 4-trichlorodiphenyl ether.  Examples (1) to (4) relate to the condensation of (1) 2 : 3-hydroxynaphthoic acid with 6-ethoxy-2-aminobenzthiazole in chlorobenzene in presence of phosphorus trichloride; (2) 2 : 3-hydroxynaphthoic acid chloride with 6-methoxy-2-aminobenzthiazole in chlorobenzene; (3) 2 : 3-hydroxynaphthoic acid with 6-methoxy-2-aminothiazole in dimethylaniline in presence of phosphorus trichloride; (4) 2 : 3-hydroxynaphthoic acid (2 mols.) with the di-(aminothiazolo)-diphenyl ether from 4 : 41-diaminodiphenyl ether and thiocyanic acid (2 mols.), in chlorobenzene in presence of phosphorus trichloride; the 4 : 41-diaminodiphenyl ether may be replaced by benzidine or tolidine.  Example (5) relates to the production in substance of the dyestuff, 21 : 4-dichloro-2-amino-diphenyl ether --> 6-ethoxy-2-(21 : 31-hydroxynaphthoyl)-amino-benzthiazole.  Example (6) relates to the production on cotton yarn of the dye-stuff, 4 : 41-dichloro-2-aminodiphenyl ether --> 6-ethoxy-2-(21 : 31-hydroxynaphthoyl)-amino-benzthiazole.  A table is also given showing the shades obtainable on cotton by producing thereon the azo dyes from various combinations of components. Specification 295,295, [Class 2 (iii)], is referred to.  2-Amino-21-, 31- and 41-methyl-4-chloro- and 2-amino-21 : 41 : 4-trichloro-diphenyl ethers are obtainable by reducing the nitro group in the ethers produced by reacting 1 : 4-dichloro-2-nitrobenzene with o-, m- or p-cresol or 2 : 4-dichlorophenol.  The Specification as open to inspection under Sect. 91 comprises also the production of amides of 2-aminoarylenethiazoles (of which 2-amino-21-methoxy-6 : 7-benzobenzthiazole is an additional example) with any aromatic hydroxy-carboxylic acids (including heterocyclic hydroxy-carboxylic acids in which the hydroxy group is aromatically bound) capable of coupling with diazo-compounds in o-position to the hydroxy group, e.g. p-cresotinic acid, 5- or 4-chloro-4- or 5-methyl-1-hydroxybenzene-2-carboxylic acid, 4 : 5-dimethyl - 1 - hydroxy - benzene - 2 - carboxylic acid, 2 - hydroxyanthracene-3-carboxylic acid, 2- or 3-hydroxydiphenylene-oxide-3- or 2-carboxylic acid, 2-hydroxycarbazole-3-carboxylic acid or its 9-methyl derivative, 5- or 7-hydroxy-a -naphthocarbazole-6-carboxylic acid or 31-methyl-7-hydroxy-a -naphthocarbazole-6-carboxylic acid. Additional examples describe the condensation of 2-amino - 6 - ethoxybenzthiazole with 1 - methyl-4-hydroxybenzene-5-carboxylic acid, salicylic acid, xylenolcarboxylic acid, 4-benzylphenol-o-carboxylic acid and 3-hydroxydiphenylene-oxide-2-carboxylic acid, and two further dyestuffs are described in the table.  This subject-matter does not appear in the Specification as accepted.