Ethyl 3-methyl-2-oxopentanoate (CAS 26516-27-8) — Sweet Heart Note Fragrance Ingredient
Ethyl 3-methyl-2-oxopentanoate
CAS 26516-27-8
What Is Ethyl 3-methyl-2-oxopentanoate?
Ethyl 3-methyl-2-oxopentanoate is a synthetic fragrance ingredient used to add fruity, caramel-like nuances to perfumes and flavored products. It’s found in everything from fine fragrances to body care items. This ester compound matters because it provides a cost-effective way to create complex gourmand and fruity accords without using natural extracts, making fragrances more accessible while maintaining quality.
Safety Profile
GENERALLY SAFEWhat Does Ethyl 3-methyl-2-oxopentanoate Smell Like?
Ethyl 3-methyl-2-oxopentanoate opens with a bright, jammy fruitiness reminiscent of overripe strawberries dipped in caramel. The initial burst evolves into a heart of baked apple with a buttery undertone, like a warm fruit tart fresh from the oven. As it dries down, it leaves a subtle maple syrup sweetness balanced by a faint woody nuance. The overall effect is gourmand without being cloying, with moderate projection that lingers pleasantly for hours.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a fruity modifier to enhance the raspberry-litchi accord, providing depth and jammy richness to balance the sharp citrus top notes.
Adds caramelized fruit facets to the gourmand heart, bridging the iris and praline notes with its buttery sweetness.
2D Molecular Structure
SMILES: CCOC(=O)C(=O)C(C)CC
Chemistry, Properties & Perfumer Guide
The Chemistry
Ethyl 3-methyl-2-oxopentanoate is a branched-chain keto ester synthesized through esterification of 3-methyl-2-oxopentanoic acid with ethanol. The molecule features both ketone and ester functional groups, which contribute to its complex odor profile. Industrial production typically involves catalytic hydrogenation or enzymatic processes. The methyl branch at the 3-position creates steric hindrance that affects volatility and odor characteristics compared to straight-chain analogs.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Odor Threshold | 0.05 ppm in air |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Gourmand modifier |
| Body Care | 0.1-0.5% | Up to 1% | Fruity top note |
Classic Accords
Tip: Use with white musks to prevent gourmand notes from becoming too heavy.
Alternatives & Comparisons
For brighter, greener fruity effects with less caramel character. Works better in citrus-heavy compositions.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards.
RIFM Assessment
Under evaluation by RIFM; preliminary data suggests low sensitization potential.
Sustainability
As a synthetic material, production avoids agricultural land use but requires petrochemical feedstocks. Manufacturers are developing greener synthesis routes using bio-based ethanol and catalytic processes to reduce environmental impact. Proper handling of waste solvents is essential in production.
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References
- Arctander, S. (1969). Perfume and Flavor Chemicals. Montclair, NJ.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID40885358
Physical Properties
| Molecular Weight | 158.197 g/mol🔬 EPA CompTox |
| Density | 0.977 g/cm^3📊 OPERA |
| Boiling Point | 195.733 °C📊 OPERA |
| Melting Point | -20.829 °C📊 OPERA |
| Flash Point | 74.861 °C📊 OPERA |
| Refractive Index | 1.42 Dimensionless📊 OPERA |
| Molar Volume | 161.568 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.322 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.322 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.322 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.32 Log10 unitless📊 OPERA |
| Water Solubility | 0.072 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.379 mmHg📊 OPERA |
| Viscosity | 1.252 cP📊 OPERA |
| Surface Tension | 29.542 dyn/cm📊 OPERA |
| Thermal Conductivity | 141.278 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 43.37 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 40.875 cm^3/mol📊 OPERA |
| Polarizability | 16.204 Å^3📊 OPERA |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
