has role azobenzenes benzamides naphthols naphthalenesulfonic acid bis(azo) compound fluorochrome poison histological dye environmental contaminant Sirius red 4B (acid form) Sirius red 4B free acid chebi_ontology 7-benzamido-4-hydroxy-3-({4-[(4-sulfophenyl)diazenyl]phenyl}diazenyl)naphthalene-2-sulfonic acid Direct Red 81 free acid C29H21N5O8S2 IGXZMQCLUNTWCC-HSBKYFPUSA-N InChI=1S/C29H21N5O8S2/c35-28-25-15-12-23(30-29(36)18-4-2-1-3-5-18)16-19(25)17-26(44(40,41)42)27(28)34-33-21-8-6-20(7-9-21)31-32-22-10-13-24(14-11-22)43(37,38)39/h1-17,35H,(H,30,36)(H,37,38,39)(H,40,41,42)/b32-31+,34-33+ 631.08316 CHEBI:88192 CAS:25188-42-5 631.639 Solaminrot 4B free acid Solaminrot 4B (acid form) Direct Red 81 (acid form) 0 C12=CC=C(C=C1C=C(C(=C2O)/N=N/C=3C=CC(=CC3)/N=N/C=4C=CC(=CC4)S(O)(=O)=O)S(O)(=O)=O)NC(C=5C=CC=CC5)=O 7-(Benzoylamino)-4-hydroxy-3-((4-((4-sulfophenyl)azo)phenyl)azo)-2-naphthalenesulfonic acid 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'. Sirius red 4B(2-)