GB441548A - The manufacture of unsymmetrical vat dyestuffs of the thioindigo series - Google Patents

Abstract

Unsymmetrical thioindigo dyestuffs are obtained by condensing 4-alkyl-5-halogen-7-alkoxy-3-hydroxythionaphthenes or 2 - derivatives thereof with 3-hydroxythionaphthenes or isatins of the benzene series or 2-derivatives thereof, the two components being at different stages of oxidation. The dyestuff may be subjected to halogenation. In examples: (1) 4-methyl-5-chlor-7-methoxy-3-hydroxythionaphthene is condensed with 4-methyl-5 : 7-dichlor - 2 : 3 - diketodihydrothionaphthene - 2 - (p-dimethylamino) anil; the dyestuff, which dyes cotton violet shades may also be obtained from 4-methyl-5 : 7-dichlor-3-hydroxythionaphthene and a 2-derivative of 4-methyl-5-chlor-7-methoxy-2 : 3-diketodihydrothionaphthene; (2) 5 - bromisatinchloride is condensed with 4-methyl - 5 - chlor - 7 - methoxy (or ethoxy)-3-hydroxythionaphthene. 4-Methyl-5-chlor-7-methoxy-3-hydroxythionaphthene or a 2-derivative thereof may be condensed with 5-chlor-7-methyl-, 4-methyl-6-chlor- or 4 : 7-dimethyl - 5 - chlor - 3 - hydroxythionaphthene, 5 - bromisatin - a - chloride, 5 : 7 - dibrom (or dichlor) isatin-a -chloride or 4-methyl-5-chlor-7-methoxyisatin - a - chloride. The Provisional Specification comprises the use as components of 7 - alkoxy - 3 - hydroxythionaphthenes containing halogen or alkyl or both in the 4- or 4- and 5-positions. Specifications 24569/10 and 281,290, [both in Class 2 (iii)], are referred to.