1-Oxaspiro[4.5]decan-2-one, 8-methyl- (CAS 94201-19-1) — Woody Middle to base Note Fragrance Ingredient
1-Oxaspiro[4.5]decan-2-one, 8-methyl-
CAS 94201-19-1
What Is 1-Oxaspiro[4.5]decan-2-one, 8-methyl-?
1-Oxaspiro[4.5]decan-2-one, 8-methyl- is a synthetic fragrance ingredient used in modern perfumery. It’s found in niche and designer fragrances, often as part of woody or musky accords. This molecule contributes unique olfactory properties that enhance complexity and longevity in perfumes. Its spirocyclic structure makes it particularly valuable for creating novel scent profiles that stand out in contemporary fragrance compositions.
Safety Profile
GENERALLY SAFEWhat Does 1-Oxaspiro[4.5]decan-2-one, 8-methyl- Smell Like?
This synthetic molecule presents a fascinating olfactory profile that evolves from initial crispness to deep warmth. The opening suggests polished wood surfaces with a faint metallic edge – imagine freshly cut oak with a whisper of clean laboratory glass. As it develops, the spirocyclic structure reveals its complexity: a subtle interplay between dry woody notes and a creamy lactonic undertone. The dry-down leaves a lingering impression of well-worn leather bound books in a sunlit library, with just a hint of musky powderiness that prevents it from becoming overly austere.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a primary note to showcase its unique woody-lactonic character, creating a minimalist yet complex fragrance that evolves intriguingly on skin over hours.
Employed as a modern woody backbone that provides both structure and subtle creaminess to balance the sharper cedar and vetiver notes.
Blended with ambroxan to create an avant-garde woody-musky accord that feels simultaneously synthetic and utterly compelling.
Used as a supporting note to add depth and modernity to the green floral composition, acting as an olfactory bridge between natural and synthetic elements.
2D Molecular Structure
SMILES: CC1CCC2(CCC(=O)O2)CC1
Chemistry, Properties & Perfumer Guide
The Chemistry
1-Oxaspiro[4.5]decan-2-one, 8-methyl- belongs to the class of spirocyclic lactones, characterized by their unique bridged ring structure. The spiro center creates molecular rigidity that contributes to its distinctive odor profile and stability in formulations. While not found in nature, its synthesis typically involves intramolecular cyclization strategies starting from appropriate cyclic ketone precursors. The 8-methyl substitution introduces subtle steric effects that modify both the volatility and odor characteristics compared to the unsubstituted parent compound.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Molecular Weight | Estimated ~168 g/mol |
| Odor Threshold | Reported extremely low (ppb range) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 8% | Modern woody modifier |
| Functional Fragrance | 0.1-1% | Up to 3% | Longevity enhancer |
| Home Care | 0.01-0.5% | Up to 1% | Subtle woody note |
Classic Accords
Tip: Use in trace amounts to add modernity to woody bases without overwhelming the composition.
Alternatives & Comparisons
Offers similar spirocyclic structure with more pronounced green and floral aspects when a less woody profile is desired.
Provides stronger woody impact but lacks the lactonic creaminess, useful for more assertive woody statements.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards. No specific usage limits established.
RIFM Assessment
No RIFM assessment published as of 2023. Considered safe at current usage levels based on structural analogs.
Sustainability
As a synthetic material, its production avoids natural resource depletion but requires petrochemical feedstocks. Modern synthesis routes aim for atom economy and reduced waste. The material’s potency means very small quantities are needed in formulations, reducing overall environmental burden compared to less powerful alternatives.
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References
- Bauer, K. et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.
- 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 94201-19-1Physical Properties
| Molecular Weight | 168.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.1🔬 PubChem |
| Boiling Point | 240 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0275 mmHg @ 25°C📊 OPERA |
| Flash Point | 105.6 °C🔬 EPA CompTox |
| Involatility Index | 0.0023💻 Calculated |
| log Kp (skin permeability) | -2.235💻 Calculated |
| SMILES | CC1CCC2(CC1)CCC(=O)O2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | balsamicwoody• leffingwell |
| Functional Groups | esterether💻 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: DTXSID70888736
Physical Properties
| Molecular Weight | 168.236 g/mol🔬 EPA CompTox |
| Density | 1.039 g/cm^3📊 OPERA |
| Boiling Point | 256.376 °C📊 OPERA |
| Melting Point | 61.819 °C📊 OPERA |
| Flash Point | 109.528 °C📊 OPERA |
| Refractive Index | 1.485 Dimensionless📊 OPERA |
| Molar Volume | 160.88 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.375 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.375 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.375 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.79 Log10 unitless📊 OPERA |
| Water Solubility | 0.022 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.014 mmHg📊 OPERA |
| Viscosity | 2.924 cP📊 OPERA |
| Surface Tension | 34.978 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 | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 46.103 cm^3/mol📊 OPERA |
| Polarizability | 18.277 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.
