PROCESS FOR THE PREPARATION OF ALPHA-BENZAMIDO-ALPHA'-HALOGEN-1,1'-DIANTHRIMIDES, ALPHA-BENZAMIDO-5' OR 8'-HALOGEN-1,1'-DIANTHRIMIDES AND THEIR APPLICATION AS INTERMEDIATES FOR VAT DYES

摘要

Prepn. of (alpha)-benzamido (alpha)'-halogeno dianthrimides -1,1' of formula (I) is claimed. (where R is opt. substd. benzamido gp. at position 4, 5 or 8 position, X is halogen at 4', 5' or 8' position) and comprises reacting an amino-benzamido anthraquinone of formula (II) with a dihalogeno anthraquinone of formula (III). Reaction is at 130-220 deg.C in presence of a Cu catalyst, and an acid scavenger, the mole ratio of (III) to (II) being above 1, pref. at least 1.35. Also claimed are cpds.(I) where R is as above and X is halogen at position 5' or 8'. Pref. R and X are at positions 4 and 5' or 5 and 5' resp. (I) are used for prodn. of vat dyes of the (alpha),(alpha)'- dibenzamido diphthaloyl carbazole type.