Why does CAS 1320-07-6 appear in more than one EU cosmetic annex?

A substance identified by CAS 1320-07-6 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts — for example, restricted under Annex III with specific conditions, while also appearing in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

How do I check if my formula contains a substance with CAS 1320-07-6?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 1320-07-6 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 1320-07-6

Q: How do I use CAS 1320-07-6 for compliance screening?

Cross-reference CAS 1320-07-6 against your raw material specification sheets and CoA documents. When it appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met. All annex entries sharing this CAS number are listed on this page.

CAS 1320-07-6 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 1320-07-6

CAS 1320-07-6PubChem CID 23675104

D&C Brown No. 1

IUPAC name: sodium 4-[(2Z)-2-[(5E)-5-[(2,4-dimethylphenyl)hydrazinylidene]-4,6-dioxocyclohex-2-en-1-ylidene]hydrazinyl]benzenesulfonate

Molecular formula: C20H17N4NaO5S
Molecular weight: 448.4 g/mol
Exact mass: 448.08173511 Da
Topological polar surface area: 149.0 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 9
Covalent units: 2
Defined stereocentres: 0

Also known as

Acid orange 24D & C Brown no. 1AO24 dyeEINECS 215-296-9CI 201708796B4I6HEC.I. ACID ORANGE 24, MONOSODIUM SALTBenzenesulfonic acid, 4-((3-((dimethylphenyl)azo)-2,4-dihydroxyphenyl)azo)-, monosodium salt

16 more reported names

BROWN 1Sodium 4-((3-((dimethylphenyl)azo)-2,4-dihydroxyphenyl)azo)benzenesulphonateSodium 4-[[3-[(dimethylphenyl)azo]-2,4-dihydroxyphenyl]azo]benzenesulphonateBenzenesulfonic acid, 4-[[3-[(dimethylphenyl)azo]-2,4-dihydroxyphenyl]azo]-, monosodium saltBenzenesulfonic acid, 4-(2-(3-(2-(dimethylphenyl)diazenyl)-2,4-dihydroxyphenyl)diazenyl)-, sodium salt (1:1)Benzenesulfonic acid, 4-((3-((2,4-dimethylphenyl)azo)-2,4-dihydroxyphenyl)azo)-, monosodium saltBenzenesulfonic acid, 4-[2-[3-[2-(dimethylphenyl)diazenyl]-2,4-dihydroxyphenyl]diazenyl]-, sodium salt (1:1)LEATHER BROWN 2GRefChem:581454C.I. Acid Orange 24FABRACID BROWN S-BMULTICUER BROWN MNOBROWN 1 [INCI]KATSU201KATSU201 [INCI]JAPAN BROWN NO. 201

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External database identifiers

ChEMBL:CHEMBL2105313

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

Records for CAS 1320-07-6

1 total

Annex

Entry

1232

Acid Orange 24 (CI 20170), when used as a substance in hair dye products

215-296-9

How CAS 1320-07-6 is used on this site

CAS 1320-07-6 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 1320-07-6 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 1320-07-6 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.

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