GB451937A - Manufacture of acid triphenylmethane dyestuffs - Google Patents

Abstract

Triarylmethane dyes.--Acid dyes of the triphenylmethane series are obtained by condensing an indole substituted in 1- and 2-positions and substituted in 3-position by a p-chloro- or p-alkoxy-benzoyl radicle with a secondary or tertiary aromatic amine, including such amines of the heterocyclic series, thereafter causing the p-chlorine atom or the p-alkoxy group to react with a primary p-alkoxy-substituted aromatic amine and sulphonating the product. Alternatively, the sulphonation may precede the reaction with the primary amine. The following examples are specified: (1) 1-Methyl-2-phenyl-3-p-chlorobenzoyl-indole (1 mol.) is melted at 100--105 DEG C. with ethylbenzyl-m-toluidine (1 mol.), in presence of phosphorus oxychloride, and the condensation product is sulphonated and melted with p-phenetidine at 120--125 DEG C.; the product dyes wool and silk clear reddish blue shades, very fast to light; (2) The ethylbenzyl-m-toluidine in (1) is replaced by ethylbenzylaniline to obtain somewhat redder dyeings; (3) 1-Methyl-2-phenyl-3-p-methoxybenzoyl-indole (1 mol.) is condensed with benzyl-o-toluidine (1 mol.) in presence of phosphorus oxychloride and the product is melted with p-phenetidine and thereafter sulphonated; the product dyes wool and silk clear violet shades, very fast to light; (4) 1 : 2-Dimethyl-3-p-chlorobenzoyl-indole (1 mol.) is condensed with dimethylaniline (1 mol.) and the product is melted with p-phenetidine and thereafter sulphonated; the product dyes wool and silk clear very reddish blue shades, very fast to light; (5) The dimethylaniline in (4) is replaced by benzyl-o-toluidine and the p-phenetidine by p-anisidine to obtain clear violet dyeings; (6) 1-Methyl-2-phenyl-3-p-chlorobenzoylindole (1 mol.) is boiled in benzene under reflux with N-ethylcarbazole (1 mol.) in presence of phosphorus oxychloride and the product is melted with p-phenetidine and thereafter sulphonated; the product dyes wool and silk reddish blue shades very fast to light; (7) The N-ethylcarbazole in (6) is replaced by 1-methyl-2-phenylindole to obtain a similar blue dyestuff. Indoles, substituted in 1- and 2-positions and substituted in 3-position by a p-chloro- or p-alkoxyl-benzoyl radicle, are obtained by reacting the corresponding 1- and 2-substituted indoles with an arylide of a p-chloro- or p-alkoxybenzoic acid in presence of phosphorus oxychloride and treating the reacting mixture with a dilute acid.