1-Amino-4-bromo-2-methylanthracene-9,10-dione and 3-Amino-N-methylbenzenesulfonanilide?condensation, then use quantity of low sulphur trioxide fuming sulfuric acid stlfonation, again into sodium salt.
Properties and Applications
blue purple. Soluble in alcohol. The strong sulfuric acid to red light purple, dilute after dark purple precipitation.