3-Methylcyclopentane-1,2-dione (CAS 765-70-8) — Sweet Middle Note Fragrance Ingredient
3-Methylcyclopentane-1,2-dione
CAS 765-70-8
What Is 3-Methylcyclopentane-1,2-dione?
3-Methylcyclopentane-1,2-dione is a synthetic ingredient used in fragrances to add caramel-like, sweet nuances. It’s found in gourmand and oriental perfumes. This compound enhances depth and richness in fragrance compositions, making it valuable for creating warm, inviting scents.
Safety Profile
GENERALLY SAFEWhat Does 3-Methylcyclopentane-1,2-dione Smell Like?
3-Methylcyclopentane-1,2-dione delivers a warm, caramelized sugar aroma with hints of toasted nuts and a subtle buttery undertone. It evolves from a sharp, sugary top note to a deep, molasses-like heart, finally settling into a soft, vanilla-like base. Its behavior in dry-down is persistent but not overwhelming, making it ideal for gourmand accords.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to enhance the gourmand profile, adding a caramelized sweetness that complements the patchouli and chocolate notes.
Contributes to the sugary, praline-like heart that defines this popular fragrance.
2D Molecular Structure
SMILES: CC1CCC(=O)C1=O
Chemistry, Properties & Perfumer Guide
The Chemistry
3-Methylcyclopentane-1,2-dione is a cyclic diketone with a five-membered ring structure. It is synthesized through oxidation reactions of methylcyclopentane derivatives. Its molecular structure allows for strong interaction with olfactory receptors, contributing to its potent sweet aroma.
Physical & Chemical Properties
| Boiling Point | N/A |
|---|---|
| Density | N/A |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Adds sweet, caramel nuances |
| Home Fragrance | 0.5-2% | Up to 3% | Enhances warm, inviting scents |
Classic Accords
Tip: Use sparingly to avoid overpowering sweetness.
Alternatives & Comparisons
Offers a similar caramel note but with less depth and more focus on pure sweetness.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under current IFRA standards.
EU Allergen Declaration
Not listed as an EU allergen.
RIFM Assessment
No significant safety concerns identified by RIFM.
Sustainability
Synthetic production ensures consistent quality and reduces environmental impact compared to natural extraction methods. Supply chain is stable with minimal ecological footprint.
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References
- PubChem Compound Summary for 3-Methylcyclopentane-1,2-dione PubChem
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 765-70-8Physical Properties
| Molecular Weight | 112.13 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.2🔬 PubChem |
| Boiling Point | 184 °C🔬 EPA CompTox |
| Vapor Pressure | 0.4898 mmHg @ 25°C📊 OPERA |
| Flash Point | 59.3 °C🔬 EPA CompTox |
| Involatility Index | 0.0499💻 Calculated |
| log Kp (skin permeability) | -3.242💻 Calculated |
| SMILES | CC1CCC(=O)C1=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | caramel• leffingwell |
| Functional Groups | ketone💻 RDKit |
| Methylcyclopentenolone has a sweet flavor somewhat similar to licorice. This compound is also reported to have a nutty odor, and a maple-licorice aroma in dilute solution.📖 Fenaroli | |
Regulatory Status
| IOFI Classification | Nature Identical📖 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: DTXSID3047716
Physical Properties
| Molecular Weight | 112.128 g/mol🔬 EPA CompTox |
| Density | 1.08 g/cm^3📊 OPERA |
| Boiling Point | 176.958 °C📊 OPERA |
| Melting Point | 106.417 °C🔬 EPA CTX |
| Flash Point | 59.999 °C📊 OPERA |
| Refractive Index | 1.463 Dimensionless📊 OPERA |
| Molar Volume | 101.703 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.037 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 0.037 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 0.037 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.95 Log10 unitless📊 OPERA |
| Water Solubility | 0.56 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.976 mmHg📊 OPERA |
| Viscosity | 1.43 cP📊 OPERA |
| Surface Tension | 34.962 dyn/cm📊 OPERA |
| Thermal Conductivity | 151.644 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 34.14 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 28.028 cm^3/mol📊 OPERA |
| Polarizability | 11.111 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.
