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CAS 1 record

CAS 104-98-3

CAS 104-98-3 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 104-98-3
CAS 104-98-3PubChem CID 736715

Urocanic Acid

Urocanic acid is an alpha,beta-unsaturated monocarboxylic acid that is prop-2-enoic acid substituted by a 1H-imidazol-4-yl group at position 3. It is a metabolite of hidtidine. It has a role as a chromophore and a human metabolite. It is a member of imidazoles and an alpha,beta-unsaturated monocarboxylic acid. It is a conjugate acid of a urocanate. — ChEBI

IUPAC name
(E)-3-(1H-imidazol-5-yl)prop-2-enoic acid
Molecular formula
C6H6N2O2
Molecular weight
138.12 g/mol
Exact mass
138.042927438 Da
XLogP3
0.0
Topological polar surface area
66.0 Ų
Hydrogen-bond donors
2
Hydrogen-bond acceptors
3
Covalent units
1
Defined stereocentres
0

Also known as

Urocaninic acid(2E)-3-(1H-imidazol-4-yl)prop-2-enoic acid3-(1H-Imidazol-4-yl)-2-propenoic acid2-Propenoic acid, 3-(1H-imidazol-4-yl)-G8D26XJJ3BNSC-663572-Propenoic acid, 3-(1H-imidazol-4-yl)-, (E)-CHEBI:27248
16 more reported names
Acid, UrocanicGlyoxalinylacrylic AcidAcid, GlyoxalinylacrylicRefChem:901492203-258-43-(1H-imidazol-5-yl)prop-2-enoic acidtrans-Urocanic acid4-imidazoleacrylic acid3465-72-3urocanateimidazoleacrylic acid(E)-3-(1H-imidazol-5-yl)acrylic acid5-Imidazoleacrylic acid(2E)-3-(1H-IMIDAZOL-4-YL)ACRYLIC ACID(E)-3-(4-Imidazolyl)acrylic acid3-Imidazol-4-ylacrylic acid
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Evidence from additional scientific databases

NIH PubChem PUG-View
Exact identifier match736715

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

  • Cosmetic Ingredient Review Conclusion: The safety of this ingredient has not been documented and substantiated. The CIR Expert Panel cannot conclude whether Urocanic Acid is safe for use in cosmetic products until such time as the appropriate safety data have been obtained and evaluated. Source: Cosmetic Ingredient Review (CIR)
  • Cosmetic Ingredient Review Finding(s): Ingredients for which the data are insufficient and their use in cosmetics is not supported Source: Cosmetic Ingredient Review (CIR)

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 ChEBINeeds review2026-08-31
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.

Records for CAS 104-98-3

1 total
No records found for this CAS number.

How CAS 104-98-3 is used on this site

CAS 104-98-3 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 104-98-3 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.