GB787311A - Vat dyestuffs of the anthraquinone series and process for their manufacture - Google Patents

Abstract

The invention comprises vat dyes containing the grouping of the formula <FORM:0787311/IV (b)/1> in which R represents a substituent (e.g. hydrogen, alkyl, phenyl, halogen, substituted amino), and the anthrapyridine nucleus may contain further substituents. The two nitrogens of the imidazole ring may be bound to an anthraquinone nucleus. They are made by treating with an alkaline agent capable of bringing about ring closure a compound containing the grouping <FORM:0787311/IV (b)/2> or substitution products thereof, which compounds may be themselves prepared by acylation and ring-closure from a 1-(o-aminoaryl-amino)-anthraquinone, e.g. using acetic anhydride, or propionyl, butyryl, chloracetyl, or phenylacetyl chloride as acylating agent, and sulphuric acid to close the ring, simultaneously of subsequently. The products dye or print cotton, linen, or regenerated cellulose, and may be used as their leuco-sulphuric ester salts. In examples: (1) 2-amino-3,11-dianthrimide (or 41- or 51-methoxy, -benzoylamino, or -nitro-substitution products thereof) is acylated with acetic or propionic anhydride in sulphuric acid to give 5,6-phthaloyl-2-methyl or ethyl-3-(11)-anthraquinonyl-benzimidazoles) followed by ring-closure with caustic soda in ethyl alcohol; (2) 2 - amino - 3,11 - dianthrimide is acylated with phenylacetyl chloride in nitrobenzene to give 3 - phenylacetylamino - 2,11 - dianthrimide which is ring-closed with sulphuric acid to give 5,6 - phthaloyl - 2 - benzyl - 3 - (11) - anthra - quinonyl - benzimidazole which is ring-closed further with caustic soda in ethyl alcohol; (3) 1 - amino - 2 : 11 - dianthrimide is reacted with acetic anhydride and sulphuric acid and product is further reacted with caustic soda in ethyl alcohol. A dyeing example using cotton is given.