Flavor ingredient regulatory record
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone is a ketone in the fruity family, FEMA GRAS under FEMA number 3659 (CAS 23726-94-5). Its odor is sweet, fruity, floral, green, tropical.
- FEMA
- 3659
- CAS
- 23726-94-5
- JECFA
- 385
- Formula
- C13H20O
- EC
- 245-845-8
GRAS status: FEMA GRAS, publication 13. Recorded by FDA in the Substances Added to Food inventory under CAS 43052-87-5.
Structure
Identity
Also known as: 2-Buten-1-one, 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, (2Z)-, 2-Buten-1-one, 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, (Z)-, (2Z)-1-(2,6,6-Trimethyl-2-cyclohexen-1-yl)-2-buten-1-one, cis-α-Damascone, (Z)-α-Damascone, (Z)-1-(2,6,6-Trimethylcyclohex-2-en-1-yl)but-2-en-1-one, (z)-1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-2-buten-1-one, 2-buten-1-one, 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, (z)-, (2z)-1-(2,6,6-trimethylcyclohex-2-en-1-yl)but-2-en-1-one, 2-buten-1-one, 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, (2z)-, a-damascone, alpha damascone.
Can cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone be labeled natural?
The process decides for cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone. It occurs in nature, so a natural-source, natural-process material is natural flavor in the US and synthetic cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone is artificial. The EU and UK follow the same logic without a middle class; Mercosur and Mexico label synthetic cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone 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
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone is FEMA GRAS under FEMA number 3659. It is cited in the Code of Federal Regulations at 21 CFR 172.515.
European Union and United Kingdom
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone was on the Union List of flavouring substances as FL 07.225 when Regulation (EU) 872/2012 adopted the list, and the entry has since been withdrawn. It does not appear in the current consolidated text of Regulation (EC) 1334/2008. Check the amending regulations for the conditions that applied to existing stock, and treat EU or UK use as closed unless another route covers it.
JECFA (WHO / FAO)
JECFA number 385, evaluated at the 51st meeting in 1998. no safety concern at current levels of intake.
Other US flags
Not on the California Proposition 65 list.
TSCA Inventory status
A flavor ingredient is also an industrial chemical. cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone appears on the EPA Toxic Substances Control Act Chemical Substance Inventory under CAS 23726-94-5, where EPA names it 2-Buten-1-one, 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, (2Z)-.
Active in US commerce
EPA designates this substance active, so no Notice of Activity Form B is required before manufacturing. 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, green, tropical.
Where it is used
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone is used in beverage, confection, fruit flavors, bakery and desserts, typically as a fruity note.
Structurally similar flavor ingredients
Flavor ingredients with a GRAS determination closest to cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone by structure. Whether one can replace it is a sensory and regulatory call; the reformulation tool works that through.
| Material | FEMA | Similarity | Occurrence |
|---|---|---|---|
| trans-alpha-Damascone | 4088 | 100% | In nature |
| delta-Damascone | 3622 | 98% | In nature |
| beta-Damascone | 3243 | 98% | In nature |
| Damascenone | 3420 | 96% | In nature |
| alpha-Ionone | 2594 | 81% | In nature |
More ketones in this index
2-Acetyl-4-isopropylpyridine · 6-Methyl-3,5-heptadien-2-one · 3-Nonen-2-one · Cycloionone · Isophorone · Pseudoionone
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone FAQ
Is cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone on the FEMA GRAS list?
It is. FEMA number 3659 covers cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone. The Code of Federal Regulations lists it at 21 CFR 172.515.
What is the FEMA number for cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone?
The FEMA number for cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone is 3659 and its CAS registry number is 23726-94-5. Its flavor category is fruity.
What is cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone used for?
cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone is described as sweet, fruity, floral, green, tropical. It shows up in beverage, confection, fruit flavors, bakery and desserts.
What did JECFA conclude about cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone?
JECFA evaluated cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone at the 51st meeting in 1998 under JECFA number 385. The panel concluded: no safety concern at current levels of intake.
Is cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone approved in the EU?
No EU FL number is on file for cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone. It has a JECFA evaluation (JECFA 385), which the EU list draws on, but the Union List entry itself should be confirmed before EU use.
Is cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone natural or artificial?
Nature makes cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone, which is why the US label turns on process. A natural route gives natural flavor; synthesis gives artificial cis-1-(2,6,6-Trimethyl-2-cyclohexenyl)-2-butenone, same molecule. The EU and UK grant the natural claim only to that natural route; Mercosur and Mexico call synthetic material identical-to-natural.
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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 ALPHA-DAMASCONE under CAS 43052-87-5 and carries its FEMA number, its JECFA flavor number. 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.