Why does CAS 66612-11-1 appear in more than one EU cosmetic annex?

A substance identified by CAS 66612-11-1 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 66612-11-1?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 66612-11-1 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 66612-11-1

Q: How do I use CAS 66612-11-1 for compliance screening?

Cross-reference CAS 66612-11-1 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 66612-11-1 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

Check this CAS number Browse annexes

Chemical identity and properties

PubChem 2D chemical structure for CAS 66612-11-1

CAS 66612-11-1PubChem CID 3017692

N-[6-[(2-Chloro-4-hydroxyphenyl)imino]-4-methoxy-3-oxo-1,4-cyclohexadien-1-YL]acetamide

IUPAC name: N-[2-[(2-chloro-4-oxocyclohexa-2,5-dien-1-ylidene)amino]-5-hydroxy-4-methoxyphenyl]acetamide

Molecular formula: C15H13ClN2O4
Molecular weight: 320.73 g/mol
Exact mass: 320.0563846 Da
XLogP3: 1.5
Topological polar surface area: 88.0 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 5
Covalent units: 1
Defined stereocentres: 0

Also known as

HC Yellow no. 8F1NQ5U8325UNII-F1NQ5U8325N-(6-((2-Chloro-4-hydroxyphenyl)imino)-4-methoxy-3-oxo-1,4-cyclohexadien-1-yl)acetamideN-{2-[(2-CHLORO-4-OXOCYCLOHEXA-2,5-DIEN-1-YLIDENE)AMINO]-5-HYDROXY-4-METHOXYPHENYL}ACETAMIDEEINECS 266-424-5HC Yellow 8Yellow No. 8

8 more reported names

IMEXINE ILDNCKSSGISBCYQW-UHFFFAOYSA-NN-(6-((2-Chloro-4-hydroxyphenyl)imino)-4-methyoxy-3-oxo-1,4-cyclo- hexadien-1-yl)acetamideAcetamide, N-(6-((2-chloro-4-hydroxyphenyl)imino)-4-methyoxy-3-oxo-1,4-cyclo- hexadien-1-yl)-N-(2'-Chloro-4'-hydroxyphenyl)-3-acetylamino-6-methoxy-1,4-benzoq- uinoneimineN-(2'-CHLORO-4'-HYDROXYPHENYL)-3-ACETYLAMINO-6-METHOXY-1,4-BENZOQUINONEIMINEACETAMIDE, N-(6-((2-CHLORO-4-HYDROXYPHENYL)IMINO)-4-METHOXY-3-OXO-1,4-CYCLOHEXADIEN-1-YL)-N-{(6E)-6-[(2-Chloro-4-hydroxyphenyl)imino]-4-methoxy-3-oxocyclohexa-1,4-dien-1-yl}acetamide

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

EPA DTXSID:DTXSID60867237
EPA DTXSID:DTXSID70879806

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 66612-11-1

1 total

Annex

Entry

1304

N-[6-[(2-Chloro-4-hydroxyphenyl)imino]-4-methoxy-3-oxo-1,4-cyclohexadien-1-yl]acetamide (HC Yellow No 8) and its salts, when used as a substance in hair dye pr…

266-424-5

How CAS 66612-11-1 is used on this site

CAS 66612-11-1 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 66612-11-1 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 66612-11-1 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.

Check this CAS number

Tools & next steps

Check your formula

Scan a full INCI list, then use CAS 66612-11-1 to cross-check any supplier documents behind the matched substances.

INCI Checker

Browse annexes

Browse all EU cosmetic regulation annexes by category.

All annexes

Search by name

Search for INCI names, aliases or related identifiers that sit alongside CAS 66612-11-1 in your documentation.