GB225544A - Manufacture of new indigoid dyestuffs of the anthraquinone series and intermediate products - Google Patents

Abstract

Anthraquinone-2-glycine-3-carboxylic acid is obtained by condensing 2-chloranthraquinone-3-carboxylic acid with glycine; in an example the condensation is effected in presence of magnesia and copper powder. Anthraquinone-2 : 3-indoxyl; anthraquinone-2 : 3-indigo; indigoid and thioindigoid dyes.-The above anthraquinone-2-glycine-3-carboxylic acid, by treatment with a condensing agent such as acetic anhydride and sodium acetate, yields anthraquinone-2 : 3-indoxyl (or the di-acetyl derivative thereof); the indoxyl derivative is converted into dyestuffs by treating with concentrated sulphuric acid, or by treatment with alkali in presence of air, or by condensation with a cyclic o-diketone or a chloride or anil thereof, for example an isatin or thioisatin, or acenaphthenequinone; the dyestuffs, which may also be subsequently halogenated, dye cotton from the hydrosulphite vat in fast red-blue to blue-black and green tints. According to examples (1) anthraquinone - 2 - glycine-3-carboxylic-acid is heated with sodium acetate and acetic anhydride and the diacetyl-indoxyl obtained converted to the anthraquinone-2 : 3-indigo by hydrolysis and oxidation with air, or by heating with sulphuric acid; the product dyes cotton in blue green tints; (2) the diacetylindoxyl is condensed with isatin or acenaphthenequinone, the products dyeing cotton in blue-green and red-blue tints respectively; the isatin may be replaced by a homologue or analogue thereof, such as a thioisatin of the benzene or naphthalene series or a chloride or anil thereof; (3) the dyestuff from the anthraquinone-indoxyl and isatin is brominated in nitrobenzene.