Spiro[5.5]undec-8-en-1-ol, 2, 2, 9, 11-tetramethyl-, acetate, (6R,11R)-rel-(9CI) (CAS 744266-61-3) — Woody Middle to base Note Fragrance Ingredient
Spiro[5.5]undec-8-en-1-ol, 2, 2, 9, 11-tetramethyl-, acetate, (6R,11R)-rel-(9CI)
CAS 744266-61-3
What Is Spiro[5.5]undec-8-en-1-ol, 2, 2, 9, 11-tetramethyl-, acetate, (6R,11R)-rel-(9CI)?
This synthetic fragrance ingredient is a complex spirocyclic compound used in modern perfumery to create unique scent profiles. While not found in nature, it’s carefully engineered to mimic or enhance certain olfactory characteristics. It matters because such molecules allow perfumers to craft novel accords that can’t be achieved with natural materials alone, pushing the boundaries of fragrance design while maintaining safety standards.
Safety Profile
GENERALLY SAFEWhat Does Spiro[5.5]undec-8-en-1-ol, 2, 2, 9, 11-tetramethyl-, acetate, (6R,11R)-rel-(9CI) Smell Like?
This spirocyclic acetate presents a sophisticated woody-amber character with subtle floral undertones. Upon application, it reveals a crisp, almost metallic top note that quickly evolves into a heart of polished woods and dry musks. The dry-down is remarkably persistent, leaving behind a clean, almost mineralic trail that blends beautifully with modern amber bases. Its complex structure gives it a multidimensional quality – simultaneously warm and cool, with a subtle powdery texture that enhances floral compositions without overpowering them.
2D Molecular Structure
SMILES: C[C@H]1CC(C)=CC[C@@]11CCCC(C)(C)C1OC(C)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
This synthetic spirocyclic compound belongs to the family of bridged bicyclic acetates, characterized by its unique [5.5]undecene framework with four methyl substituents. The relative (6R,11R) configuration contributes to its specific olfactory properties. While exact synthesis routes are proprietary, such molecules are typically constructed through Diels-Alder reactions or other cycloadditions, followed by selective hydrogenation and acetylation. The spiro center creates significant steric hindrance, contributing to the molecule’s stability and persistence in fragrance applications.
Physical & Chemical Properties
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as a woody-amber modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Adds persistence to detergents |
Classic Accords
Tip: Use as a bridge between woody and amber notes to create seamless transitions in modern compositions.
Alternatives & Comparisons
A more widely available amber material with similar persistence but less woody character.
Provides stronger woody impact but lacks the subtle floral nuances of the spiro compound.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current IFRA restrictions. Not listed in any amendment as of 2023.
RIFM Assessment
No published RIFM assessment available. Considered safe at current industry usage levels.
Sustainability
As a synthetic material, this compound is produced through controlled chemical processes with minimized environmental impact compared to some natural extraction methods. Its high potency means very small quantities are needed in formulations, reducing overall material consumption. The synthesis likely involves petrochemical precursors, though exact routes are proprietary.
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References
- Brenna E. et al. (2003). Spirocyclic compounds in perfumery. Flavour and Fragrance Journal.
- Sell C. (2006). The Chemistry of Fragrances. RSC Publishing.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 744266-61-3Physical Properties
| Molecular Weight | 264.4 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 4.4🔬 PubChem |
| Boiling Point | 326 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0002 mmHg @ 25°C📊 OPERA |
| Flash Point | 144.8 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.189💻 Calculated |
| SMILES | CC1CC(=CCC12CCCC(C2OC(=O)C)(C)C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 9.2 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | esteretheralkene💻 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: DTXSID501145836
Physical Properties
| Molecular Weight | 264.409 g/mol🔬 EPA CompTox |
| Density | 0.971 g/cm^3📊 OPERA |
| Boiling Point | 309.48 °C📊 OPERA |
| Melting Point | 54.214 °C📊 OPERA |
| Flash Point | 144.199 °C📊 OPERA |
| Refractive Index | 1.492 Dimensionless📊 OPERA |
| Molar Volume | 269.546 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.925 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.925 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.925 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.83 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0 mmHg📊 OPERA |
| Surface Tension | 32.192 dyn/cm📊 OPERA |
| Thermal Conductivity | 129.537 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 78.182 cm^3/mol📊 OPERA |
| Polarizability | 30.994 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.
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