Patent GB-411479-A (GB)
Title: The manufacture of new thiazole compounds
IPC: C07D277/66
Filed: 1932-12-05
Abstract: Hydrozy-benzo- or -naphtho-thiazoles, substituted in the 2-position with an alkyl or aryl group, are converted into o-hydroxycarboxylic acids by heating them, as alkali salts and (or) in the presence of alkali carbonate, with carbon dioxide under pressure.  The hydroxythiazoles used as starting materials are obtained from the corresponding alkoxythiazoles, which are themselves obtained by oxidizing thioacyl derivatives of alkoxy-anilines or -naphthylamines; such thioacylarylamines are obtainable, as described in German Specification 385,376, by treating the corresponding acylarylamines with phosphorus pentasulphide in xylene solution in the presence of alkali sulphide or ammonium sulphide.  The arylthiazole-o-hydroxycarboxylic acids obtained as described above may be converted by standard processes into their arylamides, e.g. into their anilides, toluidides, anisidides, or a  or b -naphthalides, and the arylamides may be coupled, in substance or on the fibre, with diazo compounds free from groups inducing solubility in water, water-insoluble dyes of various colours being produced.  In the examples, (1) 2-phenyl - 6 - hydroxybenzothiazole - 5 - carboxylic acid is prepared by heating the potassium salt of 2 - phenyl - 6 - hydroxybenzothiazole to 220 DEG  C, with carbon dioxide under pressure in the presence of potassium carbonate; (2) 7-methoxy-2-thioacetylaminonaphthalene is oxidized with potassium ferricyanide to yield a methoxy-2-methylnaphthothiazole, which is converted into a hydroxy-2-methylnaphthothiazole by treatment in toluene solution with aluminium chloride; the potassium salt of the hydroxy-2-methylnaphthothiazole is heated in the presence of potassium carbonate to 220 DEG  C. with carbon dioxide under pressure to yield a 2-methylnaphthothiazole-o-hydroxycarboxylic acid; (3) the methoxy - 2 - methylnaphthothiazole obtainable, as described in example 2, from 6 - methoxy - 2 - thioacetylamino-naphthalene is converted into the corresponding hydroxy-2-methylnaphthothiazole by treatment with mixed hydrobromic and acetic acids, and the product is converted into a carboxylic acid as described in examples 1 and 2; (4) the product of example 1 is converted into its anilide by treatment with aniline in toluene solution in the presence of phosphorus p  trichloride; (5) and (6) the products of examples 2 and 3 are similarly converted into their o-toluidides; (7) cotton is impregnated with the product of example 5, and then treated with a solution of diazotized 2 : 5 - diethoxy - 4 - benzoylaminoaniline (greenish-blue) or (example 8) 2 : 5 - dichloro - 4 - benzoylaminoaniline (bluish-red) or (example 9) 2-methoxy-5 - methyl - 4 - benzoylaminoaniline (bluish-violet); (10) cotton is impregnated with the product of example 6 and then treated with a solution of the diazotized aminoazo compound prepared by coupling diazotized 1-amino-2-methyl - 4 - nitro - 5 - methoxybenzene with 4 - aminodiphenylamine and reducing the nitro group (greenish-black); diazo compounds prepared from the following amines may also be used in examples 7-10 ;--2 : 5 - dimethoxy-4 - benzoylaminoaniline (greenish-blue); 5-chloro - 2 - aminotoluene (bluish-red); o-chloraniline (red); m-chloraniline (red); o-nitraniline (bluish-red); m - nitraniline (red); 2 : 5 - dichloraniline (bluish-red); o-toluidine (bluish-red); p-nitraniline (dull red or bordeaux); 2 - amino - 4 - chlorotoluene (bluish-red); 2 - methoxy - 4 - nitraniline (corinth); 4<1>-methoxy - 4 - aminodiphenylamine (bluish-grey or greenish-blue); 4 - amino - 2 : 5 - dimethoxyazobenzene (bluish-black); 4-phenyl amino - 2 - chloro - 5 - methoxyaniline (bluish-corinth); 2 - amino - 6 - chlorotoluene (red); 2 - nitro - 4 - methylaniline (bluish red); 2 - nitro - 4 - methoxyaniline (bluish-bordeaux); 4 - amino - 2:2<1>-dimethylazobenzene (corinth); (11) the b -naphthalide of the product of example 2 is coupled in pyridine with diazotized a -naphthylamine to form a bluish-violet dye; (12) cotton is impregnated with a 2 - phenylnaphthothiazole - o - hydroxycarboxylic acid o-toluidide, prepared from 7-methoxy - 2 - thiobenzoyaminonaphthalene by the reactions described in examples 2 and 5; the cotton is then treated with a solution of diazotized m-chloraniline, yielding a reddish-orange dyeing; each example includes formul  of the products.