BROMINATED AZATHIOXANTHENE COMPOUND AND PRODUCTION THEREOF

PROBLEM TO BE SOLVED: To obtain a brominated azathioxanthene compd. which is useful as a novel red fluorescent colorant having a high luminance and a good fastness by reacting an azathioxanthene compd. with bromine in an inert solvent. SOLUTION: An azathioxanthene compd. represented by formula II is reacted with bromine in an inert solvent in an amt. of 10-50 times that of the compd. to give an azathioxanthene compd. represented by formula I (n is 1-3). In the reaction, 1.0-1.2 mol (based on 1 mol of the compd. represented by formula II) of bromine is used to obtain a compd. represented by formula I wherein n is 1; 2.0-2.4 mol of bromine, to obtain a compd. represented by formula I wherein n is 2; and 3.0-3.6 mol of bromine, to obtain a compd. represented by formula I wherein n is 3. The reaction temp. is 100-200 deg.C. After the reaction, cooled crystals are filtered, washed with methanol and water, and dried to give objective compd. If necessary the product is purified by recrystallization.