CAS 25188-42-5 — 0 EU Cosmetic Records

Chemical identity and properties

PubChem 2D chemical structure for CAS 25188-42-5

CAS 25188-42-5PubChem CID 17463

Direct Red 81 free acid

Sirius red 4B (acid form) is 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'. It has a role as a fluorochrome, a poison, a histological dye and an environmental contaminant. It is a member of azobenzenes, a member of benzamides, a member of naphthols, a naphthalenesulfonic acid and a bis(azo) compound. It is a conjugate acid of a Sirius red 4B(2-). — ChEBI

IUPAC name: 7-benzamido-4-hydroxy-3-[[4-[(4-sulfophenyl)diazenyl]phenyl]diazenyl]naphthalene-2-sulfonic acid

Molecular formula: C29H21N5O8S2
Molecular weight: 631.6 g/mol
Exact mass: 631.08315499 Da
XLogP3: 4.7
Topological polar surface area: 224.0 Å²
Hydrogen-bond donors: 4
Hydrogen-bond acceptors: 12
Covalent units: 1
Defined stereocentres: 0

Also known as

7-(Benzoylamino)-4-hydroxy-3-((4-((4-sulfophenyl)azo)phenyl)azo)-2-naphthalenesulfonic acidRLM8W5IPXBEINECS 246-727-9DIRECT PAPER RED 4BL2-Naphthalenesulfonic acid, 7-(benzoylamino)-4-hydroxy-3-((4-((4-sulfophenyl)azo)phenyl)azo)-7-Benzamido-4-hydroxy-3-((4-((4-sulphophenyl)azo)phenyl)azo)naphthalene-2-sulphonic acid7-benzamido-4-hydroxy-3-[[4-[(4-sulphophenyl)azo]phenyl]azo]naphthalene-2-sulphonic acid2-NAPHTHALENESULFONIC ACID, 7-(BENZOYLAMINO)-4-HYDROXY-3-(2-(4-(2-(4-SULFOPHENYL)DIAZENYL)PHENYL)DIAZENYL)-

15 more reported names

2-Naphthalenesulfonic acid, 7-(benzoylamino)-4-hydroxy-3-[[4-[(4-sulfophenyl)azo]phenyl]azo]-7-(Benzoylamino)-4-hydroxy-3-[[4-[(4-sulfophenyl)azo]phenyl]azo]-2-naphthalenesulfonic acidRefChem:5891417-benzamido-4-hydroxy-3-({4-[(4-sulfophenyl)diazenyl]phenyl}diazenyl)naphthalene-2-sulfonic acidUNII-RLM8W5IPXBSolaminrot 4B free acidSirius red 4B free acidSolaminrot 4B (acid form)Sirius red 4B (acid form)(3Z)-7-benzamido-4-oxo-3-[[4-[(4-sulfophenyl)diazenyl]phenyl]hydrazinylidene]naphthalene-2-sulfonic acidDirect Red 81 (acid form)CHEBI:88192IGXZMQCLUNTWCC-UHFFFAOYSA-NOCHRJJHVPRUZAC-AAKDRMKISA-N7-benzamido-4-hydroxy-3-[(E)-[4-[(E)-(4-sulfophenyl)azo]phenyl]azo]naphthalene-2-sulfonic acid

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External database identifiers

ChEBI:CHEBI:88192
ChEMBL:CHEMBL3306477
EPA DTXSID:DTXSID6041553
PubMed:4365198

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

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