GB851571A - New pigments of the thiachromone series - Google Patents

Abstract

2 : 5-Diarylmercapto-terephthalic acids are made by hydrolysis of the corresponding methyl or ethyl esters prepared by condensing 2 : 5-dibromo- or -chloro-terephthalic dimethyl or diethyl esters with the appropriate arylthiols. Arylthiols used are thiophenol, 4-methyl-, 4-methoxy-, 3 : 5-dimethyl-, 4-methoxy-3-chloro-, 2-methoxy-5-chloro-, 2-, 3- and 4-chloro-, 2 : 4-, 2 : 5-, 3 : 4- and 3 : 5-dichloro-, 2-methyl-3-chloro-, 2-methyl-4-chloro-, 3 : 5-dimethyl-4-chloro-, 3-methylsulphonyl-, 4-dimethylamino-, and 3- and 4-acetylamino-thiophenols, 2-thionaphthol, 6-acetylamino-2-thionaphthol, and 4-and 5-acetylamino-1-thionaphthols. S-Acetylp-dimethylaminothiophenol is made by reducing p-p-bis(dimethylaminophenol) disulphide with zinc in acetic acid and acetic anhydride.ALSO:The invention comprises thiachromone pigments of the formula: <FORM:0851571/IV (c)/1> where X and Y each represent the atoms necessary to compete a benzene ring or a system of fused 6-, or 6- and 5- membered rings, such as naphthalene, pyrene and carbazole, and wherein the rings or ring systems represented by X and Y may carry non-ionic substituents, such as halogen, nitro, aryl, carbalkoxy, acylamido, alkyl and aryl-ureido and -thioureido, arylidineamino, alkanesulphonyl, hydroxy, alkoxy, aryloxy, amino and aryl- and alkylsubstituted amino, and substituted or unsubstituted alkyl, carbamyl and sulphamyl groups. The pigments are made by treating a dicarboxylic acid of the formula: <FORM:0851571/IV (c)/2> with a dehydrating or condensing agent, or when X and Y carry ureido, thioureido, benzylidineamino or acylamido groups the corresponding pigment wherein X and Y carry amino groups may be treated with an isocyanate, isothiocyanate, aldehyde or the functional derivative of an organic acid. The pigments are used in printing inks, paints, lacquers and stoving enamels and for colouring rubber, cellulose acetate, polyvinyl chloride, polyethylene, polystyrene, polyesters and polyamides giving bright yellow to purple shades.