GB803249A - Brown vat dyestuffs - Google Patents

Abstract

The invention comprises dyes of the formula <FORM:0803249/IV (c)/1> where R is nitro, amino, halogen, methyl or ethyl, n is 0 or 1, and m has a value of 0-3, and the alkali metal leuco-disulphuric ester salts thereof. They are made by heating a 2.3-dichloro -1.4-naphthoquinone with a 31-hydroxy-(benzo - 11.21.1.2 - carbazole) unsubstituted in 41-position, in presence of an acid accepter. They dye and print cotton brown shades. In examples: (1) 2.3-dichloro-1.4-naphthoquinone and 31 - hydroxy - (benzo - 11.21 : 1.2 - carbazole) are refluxed in pyridine; (2) 8-nitro-2.3-dichloro - 1.4 - naphthoquinone and 31 - hydroxy - (benzo - 11.21 : 1.2 - carbazole) are refluxed in pyridine, and the nitro body may either be used direct in dyeing or printing, when reduction of nitro to amino takes place in the vat or paste, or is reduced in a separate step with alkaline sulphide or hydrosulphite; (3) 31 - hydroxy - 8 - methyl - (benzo - 11.21.1.2 -carbazole) is heated in pyridine with 2.3-dichloo-1.4 -naphthoquinone or its 8 nitro derivative; (4) 31 - hydroxy - 7 - chloro - (benzo - 11.21.1.2-carbazole) is heated in pyridine with 2.3-dichloro-1.4-naphthoquinone or its 8-nitro derivative; (5) the product of 1 is converted to its leuco-sulphuric ester salt with iron and chlorsulphonic acid in pyridine in presence of cuprous chloride; (6) 2.3-dichloro-1.4-naphthoquinone and 31 - hydroxy - (benzo - 11.21 : 1.2 - carbazole) are heated with alcoholic potash or with a mixture of monochlorbenzene and pyridine.