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Annex II Entry 1331 07/05/2013

3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products

3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products 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: 1331

Chemical identity and properties

PubChem 2D chemical structure for CAS 27757-79-5
CAS 27757-79-5PubChem CID 80753

3-Hydroxy-4-(phenylazo)-2-naphthoic acid

IUPAC name
3-hydroxy-4-phenyldiazenylnaphthalene-2-carboxylic acid
Molecular formula
C17H12N2O3
Molecular weight
292.29 g/mol
Exact mass
292.08479225 Da
XLogP3
4.7
Topological polar surface area
82.3 Ų
Hydrogen-bond donors
2
Hydrogen-bond acceptors
5
Covalent units
1
Defined stereocentres
0

Also known as

2-Naphthalenecarboxylic acid, 3-hydroxy-4-(phenylazo)-EINECS 248-638-0NSC 11713DYMRMULFWJUGDJ-UHFFFAOYSA-N2-Naphthalenecarboxylicacid, 3-hydroxy-4-(2-phenyldiazenyl)-NSC-117133-Hydroxy-4-phenylazo-2-naphthoic acid4-phenylazo-3-hydroxy-2-naphthoic acid
3 more reported names
NCI60_000394DS-0011603-Hydroxy-4-(phenyldiazenyl)naphthalene-2-carboxylic acid
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

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

PubChem 2D chemical structure for CAS 6371-76-2
CAS 6371-76-2PubChem CID 135565537

D & C Red no. 31

IUPAC name
calcium bis(3-carboxy-1-phenyldiazenylnaphthalen-2-olate)
Molecular formula
C34H22CaN4O6
Molecular weight
622.6 g/mol
Exact mass
622.1165253 Da
Topological polar surface area
170.0 Ų
Hydrogen-bond donors
2
Hydrogen-bond acceptors
10
Covalent units
3
Defined stereocentres
0

Also known as

D&C Red No. 31Brilliant Lake MBrilliant lakered RTopaz Toner R 5Brilliant Scarlet GJapan Red 219Brilliant Red Toner RA11067 Red
16 more reported names
D and C Red No. 31Red No. 219CI 15800Red 219Symuler Brilliant Scarlet GDainichi Brilliant Scarlet GDainichi Brilliant Scarlet RGCCRIS 4906C.I. 15800 Ca SaltEINECS 228-899-7O63T5PV73PCI 15800:1 (Ca salt)R 2192-Naphthalenecarboxylic acid, 3-hydroxy-4-(phenylazo)-, calcium salt (2:1)AKA219RED 31
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

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

3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products

Regulatory information

Regulation

(EC) 2013/344

See every entry this act set

Identified ingredients

Key data

CAS
27757-79-5 -- 6371-76-2
EC
248-638-0 -- 228-899-7
Annex
II
Entry number
1331

Inventory links for 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products

Inventory Restriction reference
Ref 32719

CI 15800

CAS: 6371-76-2
EC: 228-899-7

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

Annex IV 26
Shared CAS number

CI 15800

CAS: 6371-76-2
EC: 228-899-7

What Annex II means for 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products

3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products 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.

This record is linked to 1 CosIng inventory ingredient for name and identifier cross-reference. 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).

Frequently asked questions

Yes. 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products 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 27757-79-5 -- 6371-76-2 is the unique numerical identifier assigned to 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products 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.

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 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products

This page summarizes one Annex II record for 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products 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 3-Hydroxy-4-(phenylazo)-2-naphthoic acid and its calcium salt (Pigment Red 64:1; CI 15800) when used as a substance in hair dye products, but confirm any final regulatory decision against the current official annex wording and source files.

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