C9H8O4
180.16 g/mol
Pharmaceutical IntermediateWarning
Caffeic acid
CAS331-39-5EC206-361-2
Category
Pharmaceutical Intermediate
Compound Class
Organic Acid
Primary Use
Pharmaceutical Intermediate
Caffeic acid is a naturally occurring plant constituent found in fruits, vegetables, and beverages such as coffee. It is used as a pharmaceutical intermediate and research compound, with applications explored in crystal engineering for pharmaceutical and degradable polymeric materials.
Pharmaceutical intermediateResearch compound for crystal engineering
Content scope: Information here supports chemical identification and industrial supply, research, and manufacturing contexts. It is not a therapeutic claim, medical advice, or drug-use instructions.
Restricted or banned substances
Substances on this list are banned or restricted under the named regulation. This page is a compliance reference — verify your obligations under applicable law.
Relevant lists:California Proposition 65
CAS 331-39-5
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Safety Reference
Warning
H315Causes skin irritation
H319Causes serious eye irritation
H335May cause respiratory irritation
H351Suspected of causing cancer
H361Suspected of damaging fertility or the unborn child
Regulatory Compliance1
- California Proposition 65USRegulation
Customs Tariff Classification
The international HS code for Caffeic acid (CAS 331-39-5) is 2918.29.
HS code (international, 6-digit)
2918.29
EU CN code (8-digit)
2918 29 00
Classification per the EU customs inventory ECICS (2026-07 snapshot, HS 2022). National tariff lines and product form can affect the final classification.
Identifiers
IUPAC Name
(E)-3-(3,4-dihydroxyphenyl)prop-2-enoic acid
InChIKey
QAIPRVGONGVQAS-DUXPYHPUSA-N
SMILES
C1=CC(=C(C=C1/C=C/C(=O)O)O)O
Synonyms (44)
- Caffeic acid, United States Pharmacopeia (USP)
- 3,4-Dihydroxy-trans-cinnamate
- 3,4-Dihydroxybenzeneacrylate
- 3,4-Dihydroxycinnamate, XVII
- 3,4-Dihydroxycinnamic acid
- 3,4-dihydroxycinnamate
- CAFFEIC ACID natural
- Caffeate
- Caffeic Acid 1507
- Caffeic acid pure
- Caffeic acid, 1
- Caffeic acid, >=98.0% (HPLC)
- Caffeic acid, trans-
- Cinnamic acid, 3,4-dihydroxy-
- Cinnamic acid,4-dihydroxy-
- caffeic acid
- caffeic acid, (E)-
- cis-Caffeic acid
- e-caffeic acid
- trans-caffeic acid