GB514531A - Manufacture of triarylmethane dyestuffs - Google Patents

Abstract

514,531. Dyes ; intermediates. GROVES, W. W. (I.G. Farbenindustrie Akt.-Ges.). May 9, 1938, No. 13796. [Class 2 (iii)] Triarylmethane dyestuffs, which dye wool from an acid bath greenish shades, are prepared by condensing a 4<1> - halogenbenzophenone-3- hydroxy - 4 - carboxylic acid with an alpha-arylindol, sulphonating the condensation product simultaneously with the condensation or in a separate operation and then exchanging the halogen atom for the residue of a primary or secondary aromatic amine. Alternatively, the sulphonation may be performed after the exchange of the halogen atom for the amine residue. In examples: (1) 4<1>-chlor-3-hydroxybenzophenone-4-carboxylic acid is condensed with 1-methyl-2-phenylindol, sulphonated and reacted with p-phenetidine or N-methyl-pphenetidine; (2) 4<1>-chlor-3-hydroxybenzophenone-4-carboxylic acid is condensed with 1-isobutyl-2-p-chlorphenyl-4 : 6-dimethylindol, sulphonated and reacted with N-methyl-panisidine. The 4<1>-chlorbenzophenone compounds may be replaced by the corresponding 4<1>-brom compounds. The dyestuffs may be converted into complex metal compounds. 4<1>-chlorbenzophenone-3-hydroxy-4-carboxylic acid may be prepared by condensing 3-nitro-4- toluic acid chloride with chlorbenzene to give 4<1>-chlor-3-nitro-4-methylbenzophenone, the nitro group of which is then reduced and acetylated. The methyl group is oxidized with potassium permanganate, the acetyl group removed by saponification and the amino group replaced by a hydroxy group. The 4<1>-brombenzophenone may .be prepared in a similar manner.