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CAS 1 record

CAS 4664-16-8

CAS 4664-16-8 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 4664-16-8
CAS 4664-16-8PubChem CID 78395

2,6-Dihydroxy-4-methylpyridine

IUPAC name
6-hydroxy-4-methyl-1H-pyridin-2-one
Molecular formula
C6H7NO2
Molecular weight
125.13 g/mol
Exact mass
125.047678466 Da
XLogP3
0.0
Topological polar surface area
49.3 Ų
Hydrogen-bond donors
2
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

6-hydroxy-4-methylpyridin-2(1h)-one6-Hydroxy-4-methyl-2-pyridone2,6-Dihydroxy-4-picolineUNII-0G0NNM04DT0G0NNM04DTEINECS 225-108-7HYDROXYMETHYLPYRIDONE4-PICOLINE-2,6-DIOL
9 more reported names
2-HYDROXY-4-METHYL-6-PYRIDINONERefChem:832484-methylpyridine-2,6-diol6-HYDROXY-4-METHYL-1,2-DIHYDROPYRIDIN-2-ONE2(1H)-PYRIDINONE, 6-HYDROXY-4-METHYL-4-methyl-2,6-dihydroxypyridineJJHVYGVVMBYCMQ-UHFFFAOYSA-NCS-W013519AS-63143
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.

Records for CAS 4664-16-8

1 total

How CAS 4664-16-8 is used on this site

CAS 4664-16-8 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 4664-16-8 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 4664-16-8 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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