1-Oxaspiro[4.5]decan-2-one, 8-ethyl-, trans- (CAS 91069-40-8) — Woody Base Note Fragrance Ingredient
1-Oxaspiro[4.5]decan-2-one, 8-ethyl-, trans-
CAS 91069-40-8
What Is 1-Oxaspiro[4.5]decan-2-one, 8-ethyl-, trans-?
1-Oxaspiro[4.5]decan-2-one, 8-ethyl-, trans- is a synthetic fragrance ingredient used in modern perfumery to add woody, musky, and slightly animalic nuances. It’s found in niche fragrances where a sophisticated, long-lasting base note is desired. This molecule matters because it provides a sustainable alternative to traditional animal-derived musks, offering perfumers a versatile building block for contemporary accords without ethical concerns.
Safety Profile
GENERALLY SAFEWhat Does 1-Oxaspiro[4.5]decan-2-one, 8-ethyl-, trans- Smell Like?
This synthetic musk opens with a crisp, woody character reminiscent of freshly cut cedar planks, gradually revealing a warm, slightly sweet heart reminiscent of sun-baked hay. The dry-down develops into a sophisticated animalic musk with whispers of ambergris, creating a velvety trail that lingers on skin for hours. Its behavior resembles a slow-burning incense, starting transparent but gaining depth and radiance over time.
2D Molecular Structure
SMILES: CC[C@H]1CC[C@@]2(CCC(=O)O2)CC1
Chemistry, Properties & Perfumer Guide
The Chemistry
1-Oxaspiro[4.5]decan-2-one belongs to the class of macrocyclic ketones, structurally designed to mimic natural musk compounds. Its synthesis typically involves cyclization of appropriate aliphatic precursors followed by stereoselective introduction of the ethyl group at position 8. The trans configuration is crucial for optimal olfactory properties. Unlike traditional nitro musks, this compound exhibits excellent stability and environmental persistence.
Physical & Chemical Properties
| Boiling Point | N/A |
|---|---|
| Density | N/A |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | Provides long-lasting musk foundation |
| Home Fragrance | 0.5-2% | Up to 3% | Used in diffuser oils and candles |
| Personal Care | 0.1-1% | Up to 2% | Used in soaps and lotions |
Classic Accords
Tip: Use with ionones to create seamless floral-musk transitions.
Alternatives & Comparisons
When a cleaner, more linear musk effect is desired. Has higher volatility but less animalic depth.
For formulations requiring higher intensity and diffusive power, though with less natural wood character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions. Compliant with IFRA 49th Amendment standards.
RIFM Assessment
RIFM safety assessment pending. Currently considered safe at reported usage levels.
Sustainability
As a synthetic ingredient, this musk avoids the ecological impact of animal-derived materials. Its production can be optimized for minimal waste through modern green chemistry approaches. Being biodegradable and non-bioaccumulative addresses concerns associated with older synthetic musks.
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References
- PubChem Compound Summary for 1-Oxaspiro[4.5]decan-2-one, 8-ethyl-, trans- PubChem CID
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID60891310
Physical Properties
| Molecular Weight | 182.263 g/mol🔬 EPA CompTox |
| Density | 1.01 g/cm^3📊 OPERA |
| Boiling Point | 273.868 °C📊 OPERA |
| Melting Point | 64.287 °C📊 OPERA |
| Flash Point | 112.295 °C📊 OPERA |
| Refractive Index | 1.484 Dimensionless📊 OPERA |
| Molar Volume | 177.316 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.8 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.8 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.8 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.66 Log10 unitless📊 OPERA |
| Water Solubility | 0.011 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.012 mmHg📊 OPERA |
| Viscosity | 2.186 cP📊 OPERA |
| Surface Tension | 35.011 dyn/cm📊 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 | 50.734 cm^3/mol📊 OPERA |
| Polarizability | 20.112 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.
