7,9-Dimethylspiro[5.5]undecan-3-one (CAS 83863-64-3) — Woody Middle to base Note Fragrance Ingredient
7,9-Dimethylspiro[5.5]undecan-3-one
CAS 83863-64-3
What Is 7,9-Dimethylspiro[5.5]undecan-3-one?
7,9-Dimethylspiro[5.5]undecan-3-one is a synthetic fragrance ingredient used in modern perfumery. It’s found in niche and designer fragrances, often contributing to woody or musky accords. This molecule matters because it represents how modern chemistry expands perfumers’ palettes, creating novel scent profiles impossible with natural materials alone.
Safety Profile
USE WITH AWARENESSWhat Does 7,9-Dimethylspiro[5.5]undecan-3-one Smell Like?
This synthetic ketone delivers a complex woody-musky character with intriguing nuances. Initially presents as crisp, almost camphoraceous, then evolves into a dry cedar-like heart with subtle animalic undertones. The dry-down reveals remarkable persistence – a polished wood effect reminiscent of antique furniture wax. Unlike traditional musks, it maintains structural definition without becoming diffuse, making it valuable for modern woody compositions requiring both warmth and precision.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the smoky cedar core, providing molecular precision to the natural wood notes. Its spiro structure creates unusual diffusion patterns that enhance the fragrance’s sillage.
Employed as a skeletal framework for the dense coniferous accord, lending structural clarity to the resinous overload while preventing muddiness.
2D Molecular Structure
SMILES: CC1CCC2(CCC(=O)CC2)C(C)C1
Chemistry, Properties & Perfumer Guide
The Chemistry
A bicyclic spiro ketone with unique structural constraints that influence its odor properties. The spiro junction creates conformational rigidity, while the ketone group provides hydrogen bonding sites. Synthesized through complex cyclization reactions, often starting from terpene precursors. The dimethyl substitution pattern creates steric hindrance that slows degradation, contributing to its notable persistence.
Physical & Chemical Properties
| Molecular Class | Bicyclic spiro ketone |
|---|
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Woody-musky modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Longevity booster |
Classic Accords
Tip: Use with ionones to create dimensional woody effects that evolve over time.
Alternatives & Comparisons
Similar structural motif but more floral-green character. Prefer when needing lift in woody compositions.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards.
RIFM Assessment
Not currently evaluated by RIFM – considered low priority due to limited commercial use.
Sustainability
As a synthetic material, production avoids natural resource depletion. Energy-intensive synthesis routes may offset this benefit. Future green chemistry approaches could improve its environmental profile.
Explore 7,9-Dimethylspiro[5.5]undecan-3-one
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References
- Brenna, E. et al. (2003). Spirocyclic Fragrance Compounds. Flavour and Fragrance Journal.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 83863-64-3Physical Properties
| Molecular Weight | 194.31 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.5🔬 PubChem |
| Boiling Point | 249 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0562 mmHg @ 25°C📊 OPERA |
| Flash Point | 110.5 °C🔬 EPA CompTox |
| Involatility Index | 0.0043💻 Calculated |
| log Kp (skin permeability) | -1.4💻 Calculated |
| SMILES | CC1CCC2(CCC(=O)CC2)C(C1)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | muskywoody• leffingwell |
| Functional Groups | ketone💻 RDKit |
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: DTXSID40868762
Physical Properties
| Molecular Weight | 194.318 g/mol🔬 EPA CompTox |
| Density | 0.951 g/cm^3📊 OPERA |
| Boiling Point | 267.504 °C📊 OPERA |
| Melting Point | 23.045 °C📊 OPERA |
| Flash Point | 115.728 °C📊 OPERA |
| Refractive Index | 1.481 Dimensionless📊 OPERA |
| Molar Volume | 204.456 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.97 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.97 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.97 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.67 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.022 mmHg📊 OPERA |
| Viscosity | 3.148 cP📊 OPERA |
| Surface Tension | 32.778 dyn/cm📊 OPERA |
| Thermal Conductivity | 125.422 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 17.07 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 58.23 cm^3/mol📊 OPERA |
| Polarizability | 23.084 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.
