How is Disodium 8-anilino-5-({4-[(3-sulfonatophenyl)diazenyl]-1-naphthyl}diazenyl)-1-naphthalenesulfonate (CAS: 3351-05-1) typically synthesized?

Disodium 8-anilino-5-({4-[(3-sulfonatophenyl)diazenyl]-1-naphthyl}diazenyl)-1-naphthalenesulfonate is synthesized through a multi-step process involving diazotization, coupling, and sulfonation reactions. Commonly, this involves the diazotization of an aromatic amine, followed by coupling with a naphthoquinone derivative, and finally, sulfonation. The reaction conditions include the use of concentrated acids and appropriate catalysts to achieve high yields and selectivity.