Sirius red 4B (acid form)
sirius red 4b (acid form)
A naphthalenesulfonic acid that is 7-amino-4-hydroxy-3-({4-[(4-sulfophenyl)diazenyl]phenyl}diazenyl)naphthalene-2-sulfonic acid in which one of the amino hydrogens is replaced by a benzoyl group. The disodium salt is the histological dye 'Sirius red 4B'.