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Annex II Entry 1635 CMR03/08/2020

Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one

Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 1635
CMR

Chemical identity and properties

PubChem 2D chemical structure for CAS 104653-34-1
CAS 104653-34-1PubChem CID 91771

Difethialone

Difethialone is a member of benzenes, a member of naphthalenes and a ring assembly. — ChEBI

IUPAC name
3-[3-[4-(4-bromophenyl)phenyl]-1,2,3,4-tetrahydronaphthalen-1-yl]-2-hydroxythiochromen-4-one
Molecular formula
C31H23BrO2S
Molecular weight
539.5 g/mol
Exact mass
538.06021 Da
XLogP3
8.3
Topological polar surface area
62.6 Ų
Hydrogen-bond donors
1
Hydrogen-bond acceptors
3
Covalent units
1
Defined stereocentres
0

Also known as

DifethiaroBaraki;LM 22193-(3-(4'-Bromo(1,1'-biphenyl)-4-yl)-1,2,3,4-tetrahydro-1-naphthalenyl)-4-hydroxy-2H-1-benzothiapyran-2-one3-[3-(4'-Bromo[1,1'-biphenyl]-4-yl)-1,2,3,4-tetrahydro-1-naphthalenyl]-4-hydroxy-2H-1-benzothiopyran-2-oneDifethialone [ISO]3-(3-(4'-bromo-[1,1'-biphenyl]-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl)-4-hydroxy-2H-thiochromen-2-oneHSDB 7119UNII-KOL4VXI5O0
16 more reported names
C31H23BrO2SDifethialonDifethiarol (JAN)KOL4VXI5O0CHEBI:81893VSVAQRUUFVBBFS-UHFFFAOYSA-NTox21_1139503-[3-[4-(4-bromophenyl)phenyl]tetralin-1-yl]-2-hydroxy-thiochromen-4-oneDifethialone 10 |Ig/mL in Acetonitrile2H-1-Benzothiapyran-2-one, 3-(3-(4'-bromo(1,1'-biphenyl)-4-yl)-1,2,3,4-tetrahydro-1-naphthalenyl)-4-hydroxy-2H-1-Benzothiopyran-2-one, 3-(3-(4'-bromo(1,1'-biphenyl)-4-yl)-1,2,3,4-tetrahydro-1-naphthalenyl)-4-hydroxy-Difethialone 10 microg/mL in AcetonitrileHY-113958CAS-104653-34-1CS-0064779(3-[3-[4-(4-bromophenyl) phenyl]-1,2,3,4-tetrahydronaphthalen-1-yl]-2-hydroxythiochromen-4-one
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Evidence from additional scientific databases

EMBL-EBI ChEBI
Exact identifier matchCHEBI:81893

Difethialone

Formula
C31H23BrO2S
Average mass
539.494 g/mol
Monoisotopic mass
538.06021 Da
Formal charge
0
  • benzenes — is a (CHEBI:22712)
  • naphthalenes — is a (CHEBI:25477)
  • ring assembly — is a (CHEBI:36820)
  • benzenes — is a (CHEBI:22712)
  • naphthalenes — is a (CHEBI:25477)
  • ring assembly — is a (CHEBI:36820)
Cross-references from this source
  • CAS: 104653-34-1 — KEGG COMPOUND
  • MANUAL_X_REF: 233 — PPDB
  • MANUAL_X_REF: C18695 — KEGG COMPOUND

Mapped by: Exact CAS cross-reference in the ChEBI compound record. Retrieved: 2026-08-31. Open source record

NIH PubChem PUG-View
Exact identifier match91771

Attributed physical-property, hazard, environmental and use annotations.

Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record

Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.

Additional source coverage and match status
SourceResultChecked
EMBL-EBI ChEBIExact match2026-08-31
NIH PubChem PUG-ViewExact match2026-08-31

A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one

Chemical / IUPAC name

3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one

Regulatory information

Regulation

(EU) 2019/1966

See every entry this act set

CMR

CategoryCarcinogenicMutagenicReprotoxic
Cat. 1B——✓

Key data

CAS
104653-34-1
EC
600-594-7
Annex
II
Entry number
1635

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

What Annex II means for Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one

Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).
  • This substance has CMR classification. Review the CMR table above and verify current Annex II/III status before use.

Frequently asked questions

Yes. Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 104653-34-1 is the unique numerical identifier assigned to Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one has a CMR (carcinogenic, mutagenic or reprotoxic) classification under EU CLP Regulation. Under Article 15 of EU Cosmetics Regulation 1223/2009, CMR substances of category 1A or 1B are prohibited in cosmetics unless specifically permitted. Category 2 CMR substances may be used only if assessed safe by the SCCS. Always verify current annex status and any applicable derogations before use.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one

This page summarizes one Annex II record for Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one, but confirm any final regulatory decision against the current official annex wording and source files.

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