Patent ID: 7524979

Claim:
A process for preparing a colorant of the formula wherein Y is a hydrogen atom or a bromine atom, n is an integer of 0, 1, 2, 3, or 4, R 1 is an alkylene group or an arylalkylene group, R 2 is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, and R 4 is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, which comprises (a) preparing a first reaction mixture by admixing (1) leucoquinizarin and, optionally, quinizarin, (2) an aminobenzene substituted with an alcohol group of the formula —R 1 —OH, (3) boric acid, and (4) an optional solvent, and heating the first reaction mixture to prepare an alcohol-substituted colorant of the formula followed by (b) converting the colorant thus prepared to either (i) an ester-substituted colorant by reaction with an esterification compound which is either (A) an anhydride of the formula or (B) an acid of the formula R 2 COOH in the presence of an optional esterification catalyst, or (ii) a urethane-substituted colorant by reaction with an isocyanate compound of the formula R 4 —N═C═O, and (c) brominating the colorant thus prepared, wherein either conversion to ester or urethane can be performed before bromination or bromination can be performed before conversion to ester or urethane.