2-Methyl-3-(1-oxopropoxy)-4H-pyran-4-one (CAS 68555-63-5) — Sweet Middle Note Fragrance Ingredient
2-Methyl-3-(1-oxopropoxy)-4H-pyran-4-one
CAS 68555-63-5
What Is 2-Methyl-3-(1-oxopropoxy)-4H-pyran-4-one?
2-Methyl-3-(1-oxopropoxy)-4H-pyran-4-one is a synthetic aroma chemical used to create warm, caramel-like notes in fragrances. You’ll encounter it in gourmand perfumes and some flavored products. This ingredient matters because it adds depth and richness to sweet compositions, helping create the illusion of edible notes without actual food ingredients.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methyl-3-(1-oxopropoxy)-4H-pyran-4-one Smell Like?
This pyranone derivative delivers a complex olfactory profile that evolves from initial buttery caramel to deeper maple syrup nuances. The top note presents as slightly burnt sugar with a lactonic creaminess, transitioning to a heart of toasted marshmallow and brown butter. In drydown, it leaves a persistent vanillic warmth with hints of malted milk powder. The character is distinctly gourmand but avoids cloying sweetness through its subtle woody undertones.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a caramelic modifier in the legendary gourmand base, contributing to the fragrance’s edible-patchouli illusion.
Enhances the coffee-vanilla accord with its toasted sugar character, adding dimensionality to the sweet base.
2D Molecular Structure
SMILES: CCC(=O)OC1=C(C)OC=CC1=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methyl-3-(1-oxopropoxy)-4H-pyran-4-one belongs to the pyranone class of heterocyclic compounds. While not found in nature, it shares structural similarities with naturally occurring maltol derivatives. Industrial synthesis typically involves condensation reactions of diketones with esterified hydroxy compounds. The molecule’s ketone and ester functionalities contribute to its thermal stability and moderate volatility.
Physical & Chemical Properties
| Appearance | Pale yellow liquid |
|---|---|
| Boiling Point | Estimated 250-280°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Gourmand accords |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Food-flavored products |
Classic Accords
Tip: Use with vanillin derivatives to boost caramel effects without increasing sweetness perception.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current IFRA restrictions. Listed on IFRA Transparency List.
GHS Classification
RIFM Assessment
Not currently evaluated by RIFM. Considered safe at reported usage levels.
Sustainability
As a synthetic material, production avoids agricultural impacts but requires petrochemical feedstocks. Manufacturers are increasingly adopting green chemistry principles in synthesis. Biodegradability studies indicate moderate environmental persistence.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 68555-63-5Physical Properties
| Molecular Weight | 182.17 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.9🔬 PubChem |
| Boiling Point | 153 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -3.172💻 Calculated |
| SMILES | CCC(=O)OC1=C(OC=CC1=O)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | caramelfruitystrawberry• leffingwell |
| Functional Groups | esteretheraromatic💻 RDKit |
| Maltol propionate has a strawberry-like odor and taste.📖 Fenaroli | |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID90887463
Physical Properties
| Molecular Weight | 182.175 g/mol🔬 EPA CompTox |
| Density | 1.177 g/cm^3📊 OPERA |
| Boiling Point | 279.714 °C📊 OPERA |
| Melting Point | 100.888 °C📊 OPERA |
| Flash Point | 131.12 °C📊 OPERA |
| Refractive Index | 1.5 Dimensionless📊 OPERA |
| Molar Volume | 152.019 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.265 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.265 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.265 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.72 Log10 unitless📊 OPERA |
| Water Solubility | 0.025 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.004 mmHg📊 OPERA |
| Surface Tension | 37.318 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 56.51 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 4 count💻 Computed |
| Rotatable Bonds | 2 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 44.748 cm^3/mol📊 OPERA |
| Polarizability | 17.74 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.
