The starting material for the synthesis of these compou6ds was alizarin (IV). Reaction of this with toluene-p-sulphonyl chloride gave 2-toluene-p-sulphonylalizarin (V)[3]. Bromination or chlorination of (V) afforded 4-bromo-(VI) and 4-chloro-2-O-toluene-p-sulphonylalizarin (VII), which were hydrolyzed to 4-bromoalizarin (VIII) and 4-chloroalizarin (IX)[4].
