Flavor ingredient regulatory record

3-Methyl-4-phenyl-3-buten-2-one

3-Methyl-4-phenyl-3-buten-2-one is a ketone in the fruity family, FEMA GRAS under FEMA number 2734 (CAS 1901-26-4). Its odor is sweet, fruity, floral, caramel, buttery.

FEMA
2734
CAS
1901-26-4
JECFA
821
EU FL
07.027
Formula
C11H12O
EC
217-599-1

GRAS status: FEMA GRAS, publication 3. Recorded by FDA in the Substances Added to Food inventory under CAS 1901-26-4.

Structure

2D structure of 3-Methyl-4-phenyl-3-buten-2-one
Structure of 3-Methyl-4-phenyl-3-buten-2-one, C11H12O. Drawn from the canonical SMILES.

Identity

IUPAC name (E)-3-methyl-4-phenylbut-3-en-2-one
CAS number 1901-26-4
FEMA number 2734
Molecular formula C11H12O
Molecular weight 160.22 g/mol
SMILES CC(=O)/C(C)=C/c1ccccc1
InChIKey BQJFBHBDOAIIGS-CMDGGOBGSA-N
PubChem CID 5370646
EC number 217-599-1
Chemical class Ketone
Boiling point 127 °C
Flash point 47 °C

Also known as: 3-Buten-2-one, 3-methyl-4-phenyl-, 3-Methyl-4-phenylbut-3-en-2-one, Methyl α-methylstyryl ketone, 4-Phenyl-3-methyl-3-buten-2-one, NSC 46888, 3-methyl-4-phenylbut-3-en-2-one, 3-buten-2-one, 3-methyl-4-phenyl-, benzylidene methyl ethyl ketone, methylbenzylideneacetone, 4-phenyl-3-methyl-3-buten-2-one, 3-benzylidene-2-butenone, 1-methyl-1-benzylidene-acetone.

Can 3-Methyl-4-phenyl-3-buten-2-one be labeled natural?

Since 3-Methyl-4-phenyl-3-buten-2-one is found in nature, US labeling follows how it was obtained: natural flavor from a natural source and a natural process, artificial when 3-Methyl-4-phenyl-3-buten-2-one is synthesized. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic 3-Methyl-4-phenyl-3-buten-2-one identical-to-natural.

United States
Natural or artificial, by process
European Union and UK
Natural only from natural material
Mercosur and Mexico
Natural or identical-to-natural

How each market defines the classes: natural vs artificial flavor under 21 CFR 101.22.

Regulatory status, with citations

United States

3-Methyl-4-phenyl-3-buten-2-one is FEMA GRAS under FEMA number 2734. It is cited in the Code of Federal Regulations at 21 CFR 172.515.

21 CFR 172.515

European Union and United Kingdom

Listed on the Union List of flavouring substances as FL 07.027, Annex I Part A under Regulation (EC) 1334/2008, evaluation status approved (EFSA). The UK retains the same list.

JECFA (WHO / FAO)

JECFA number 821, evaluated at the 57th meeting in 2001. No safety concern at current levels of intake when used as a flavouring agent.

JECFA monograph

Other US flags

Not on the California Proposition 65 list.

TSCA Inventory status

A flavor ingredient is also an industrial chemical. 3-Methyl-4-phenyl-3-buten-2-one appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 1901-26-4, where EPA names it 3-Buten-2-one, 3-methyl-4-phenyl-.

Inactive in US commerce

EPA designates this substance inactive, so a Notice of Activity Form B is required before anyone manufactures or processes it again. Being FEMA GRAS does not change that. What active and inactive mean.

EPA publishes no regulatory flags on this listing. What the flags mean.

From the EPA non-confidential TSCA Inventory, July 2026 release. EPA also maintains a confidential portion it does not publish. Search the Inventory by CAS number.

Odor and taste

Odor: Sweet, fruity, floral, caramel, buttery.

Where it is used

3-Methyl-4-phenyl-3-buten-2-one is used in beverage, confection, flavoring and baked goods, typically as a fruity note.

Structurally similar flavor ingredients

Flavor ingredients with a GRAS determination closest to 3-Methyl-4-phenyl-3-buten-2-one by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.

MaterialFEMASimilarityOccurrence
4-Phenyl-3-buten-2-one288192%In nature
p-Methylcinnamaldehyde364082%In nature
p-Methoxy-alpha-methyl-cinnamaldehyde318276%In nature
Methyl cinnamate269874%In nature
4-(p-Tolyl)-2-butanone307472%In nature

More ketones in this index

5-Methyl-5-hexen-2-one · 2-Hepten-4-one · 2-Heptanone · d,l-Isomenthone · (E,Z)-4-Octen-3-one · Isophorone

3-Methyl-4-phenyl-3-buten-2-one FAQ

Does 3-Methyl-4-phenyl-3-buten-2-one have FEMA GRAS status?

3-Methyl-4-phenyl-3-buten-2-one holds FEMA GRAS status under FEMA number 2734. It is also codified at 21 CFR 172.515.

How do I cite 3-Methyl-4-phenyl-3-buten-2-one by FEMA or CAS number?

Cite 3-Methyl-4-phenyl-3-buten-2-one as FEMA 2734 or CAS 1901-26-4; both point to the same entry. FEMA files it in the fruity flavor category.

Can 3-Methyl-4-phenyl-3-buten-2-one be labeled a natural flavor?

3-Methyl-4-phenyl-3-buten-2-one occurs in nature, so the label depends on the route: 3-Methyl-4-phenyl-3-buten-2-one won from a natural source by a physical, enzymatic or microbiological process is natural flavor in the United States, and synthesized 3-Methyl-4-phenyl-3-buten-2-one is artificial. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.

Can 3-Methyl-4-phenyl-3-buten-2-one be used in the EU and UK?

3-Methyl-4-phenyl-3-buten-2-one is on the EU Union List of flavouring substances as FL 07.027 (Annex I Part A) under Regulation 1334/2008.

Has JECFA evaluated 3-Methyl-4-phenyl-3-buten-2-one?

Yes. JECFA number 821, evaluated at the 57th meeting in 2001. Conclusion: No safety concern at current levels of intake when used as a flavouring agent.

What does 3-Methyl-4-phenyl-3-buten-2-one smell and taste like, and where is it used?

The odor of 3-Methyl-4-phenyl-3-buten-2-one is sweet, fruity, floral, caramel, buttery. Typical uses are beverage, confection, flavoring and baked goods.

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Sources and attribution. The identity and regulatory facts on this page are taken from the FDA Substances Added to Food inventory, a US government record, which lists this substance as 3-METHYL-4-PHENYL-3-BUTENE-2-ONE under CAS 1901-26-4 and carries its FEMA number, its JECFA flavor number and its 21 CFR citations. The inventory is searchable at FDA. FDA records its technical effect as flavoring agent or adjuvant.

A FEMA GRAS conclusion is reached by the Expert Panel of the Flavor and Extract Manufacturers Association of the United States, and the FEMA number names that conclusion. FEMA publishes its own entry for this substance in the FEMA Flavor Library, which is the authoritative record of what the Panel decided and is worth reading alongside this page.

Ambrose Compliance is not affiliated with, endorsed by, or sponsored by FEMA. FEMA and FEMA GRAS are used here as identifiers for a published regulatory determination, not as marks of any relationship between FEMA and Ambrose.

About this page. Facts come from the FDA Substances Added to Food inventory, the Code of Federal Regulations, the EPA TSCA Inventory, the EU Union List, JECFA and the Ambrose database, with FEMA's published determination cited where it applies; parts of the text are written by Ambrose AI, which can make mistakes. Check the cited source before relying on anything here. This is not regulatory or legal advice.