How is Disodium 7-(benzoylamino)-4-hydroxy-3-({4-[(4-sulfonatophenyl)diazenyl]phenyl}diazenyl)-2-naphthalenesulfonate (CAS: 2610-11-9) typically synthesized?

Disodium 7-(benzoylamino)-4-hydroxy-3-({4-[(4-sulfonatophenyl)diazenyl]phenyl}diazenyl)-2-naphthalenesulfonate (CAS: 2610-11-9) is synthesized through a multi-step process involving diazotization, coupling, and sulfonation reactions. Commonly, the diazonium salt is generated from a phenolic compound, which is then coupled with a naphthalene derivative. Sulfonation is typically carried out using sulfur trioxide or fuming sulfuric acid, under careful temperature and pH control to achieve high yield and selectivity.